ct ROSE b ” ed Desee fe BEE i pray ia big f a 8 Bok ¥ is Satta) aN igteattyy, aris oaerarS gts te eiawes ye ey Mn 20 Mayees Nira bg ghee Palen Boe Fad 5 2 Fitte Beets ata axny§ 134, Sash Saisty se ih yas den tt ahs baat ea seta es Ne a Sabet eres Manatees fron AO ated Ne oa siet ae OE ere ee ie we pater de uten. frat ope th, ATH wz Wg eeene ves es tet ee Pry | VELIGER | A Quarterly published by | CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. | Berkeley, California /R. Stohler (1901-2000), Founding Editor Volume 45 January 2, 2002 to October 1, 2002 TABLE OF CONTENTS Number 1 (January 2, 2002) Northeastern Pacific sacoglossan opisthobranchs: natural history review, bibliography, and prospectus (Cxanpusivs ID), WRONMIVIOG socccsccvocdnvc0s0tc0n00n 1 Trogloconcha, a new genus of larocheine Scissurellidae (Gastro- poda: Verigastropoda) from tropical Indo-Pacific submarine caves TOMOKI KASE AND YASUNORI KANO ............---.- 25 Reproductive cycle of the bivalves Ensis macha (Molina, 1782) (Solenidae), Tagelus dombeii (Lamarck, 1818) (Solecurti- dae), and Mulinia edulis (King, 1831) (Mactridae) in south- ern Chile Maria H. AVELLANAL, EDUARDO JARAMILLO, ELENA CLASING, PEDRO QUIJON, AND HERALDO CONTRERAS .. 33 Sclerochronology and growth of the bivalve mollusks Chione (Chionista) fluctifraga and C. (Chionista) cortezi in the northern Gulf of California, Mexico BERND R. SCHONE, DAviD H. GOODWIN, KARL W. FLessaA, DAvip L. DETTMAN, AND PETER D. ROOPNARINE sic siysasi) eis cain os eee eee ee ee 45 The influence of hunger and olfactory cues on the feeding be- havior of the waved whelk, Buccinum undatum on the blue mussel, Mytilus edulis JOHN’ €. THOMPSON). 22s Sac oo ae ee SS) Larval development, precompetent period, and a natural spawn- ing event of the pectinacean bivalve Spondylus tenebrosus (Reeve, 1856) P.,ED' PARNELL 2 .h25 ance aes on ee 58 Mass exhumation and deposition of Mulinia lateralis (Bivalvia: Mactridae) on an intertidal beach, St. Catherines Island, Georgia, USA CAROL M. CLEVELAND, ROBERT S. PREZANT, HAROLD B. ROLLINS, RONALD TOLL, AND JENNIFER WYLIE .... 65 The natural diet of the Argentinean endemic snail Chilina par- chappi (Basommatophora: Chilinidae) and two other coex- isting pulmonate gastropods A. L. ESTEBENET, N. J. CAZZANIGA, AND N. V. PIZANI .. 71 Designation of a lectotype for Succinea grosvenorii Lea (Mol- lusca: Gastropoda: Pulmonata) ARTIE: LE. METCALE 45.26 63 ene 3 Oe 79 Number 2 (April 1, 2002) The genus Nodilittorina von Martens, 1897 (Gastropoda: Litto- rinidae) in the eastern Pacific Ocean, with a discussion of biogeographic provinces of the rocky-shore fauna DA VADIG.. REID! iis ctchc. uy ernie ee) Coes leu ee ee eee 85 A useful marker for the study of neural development in cephalopods SHUICHI SHIGENO AND MASAMICHI YAMAMOTO .......- 171 Crepidula dilatata Lamarck, 1822, truly living in the southwest- ern Atlantic PABLO E. PENCHASZADEH, GUIDO PASTORINO, AND IMUASXIIMIE TAINO @IEEDON | a cliente ee 172 Number 3 (July 2, 2002) New information on late Cretaceous, Paleocene, and Eocene ner- itid gastropods from the North American Pacific slope RICHARD L. SQUIRES AND LOUELLA R. SAUL ........ Wy Review of the genus Actinocyclus Ehrenberg, 1831 (Opistho- branchia: Doridoidea) ANGEL VALDES wou. teh eos eis Eee ee aa area 193 Owengriffithsius, anew genus of cyclophorid land snails endemic to northern Madagascar GNIS CE, IBVISAION socascccoco0sbccc0vucc 203 Geographic variation of shell geometry in the abyssal snail Xy- loskenea naticiformis (Jeffreys, 1883) MICHAEL A. REX, ANNELL BOND, RON J. ETTER, ANDREA GRREXVAND) CAROU sia STUART Earnie iene neice 218 Intermating interval and number of sperm delivered in the si- multaneously hermaphroditic land snail Arianta arbustorum (Pulmonata: Helicidae) CLAUDIA HANGGI, ROLF LOCHER, AND BRUNO BAUR... 224 On the adaptive function of the love dart of Helix aspersa IMUCEUNTL, AN, IUONNDOUVA. caonoscoaceos00gco000cs 231 Identical carbonic anhydrase contributes to nacreous or prismatic layer formation in Pinctada fucata (Mollusca: Bivalvia) T. Miyasuita, R. TAKAGI, H. MIyAMoTO, AND A. MATSUSHIRO: «ties ie cole aoe a ie oe ee 250 Thin layer chromatographic analysis of lutein and B-carotene in Biomphalaria glabrata maintained on a high fat diet YONGHYUN KIM, BERNARD FRIED, AND JOSEPH SHERMA 256 Kalidos griffithshauchleri, sp. nov., Madagascar’s largest heli- carionid snail (Pulmonata) KENNETH GSE MBERTONT oleic Eien enn eae 259 Fungi and other items consumed by the blue-gray taildropper slug (Prophysaon coeruleum) and the papillose taildropper slug (Prophysaon dubium) REx McGraw, NANCY DUNCAN, AND EFREN CAZARES 261 The taxonomic status of the freshwater snail Antillobia margalefi Altaba, 1993, from Hispaniola (Hydrobiidae: Cochliopinae) IEIge}D) (Gh, MIEOWIION coccoscaneccccvac0000b0 50% 264 Predation of water bug Sphaerodema rusticum on the freshwater snails Lymnaea (Radix) luteola and Physa acuta GVADIDYAVAND) Sa Kn VA UIE nr eee eae nenene eee 267 Two genera of North American freshwater snails: Marstonia Baker, 1926, resurrected to generic status, and Floridobia, new genus (Prosobranchia: Hydrobiidae: Nymphophilinae) FRED G. THOMPSON AND ROBERT HERSHLER ........ 269 Number 4 (October 1, 2002) Movement and wave dislodgment of mussels on a wave-exposed rocky shore HEATHER L. HUNT AND ROBERT E. SCHEIBLING ...... 273 Ankoravaratra, a new genus of land snails endemic to northern Madagascar (Cyclophoroidea: Maizaniidae?) IMENNEDHICeEMBERTON 6 ssa. fe oe 2 see ee os 278 Dichotomous life history patterns for the nudibranch Dendron- otus frondosus (Ascanius, 1774) in the Gulf of Maine CEIAD G.. SGSON socecbessoenane ao eaoean bao e 290 A new species of Granigyra Dall, 1889 (Gastropoda: Skeneidae) from Brazil and a review of known western Atlantic species PAULINO JOSE SOARES DE SOUZA, JR. AND ALEXANDRE IDYUNS JIMTERNTUN, Gyalalo snita aenvan ciel ania ern Beaomn sea | ance 299 A new species of Afttiliosa (Muricidae: Neogastropoda) from the upper Eocene/lower Oligocene Suwannee Limestone of Florida GREGORY S. HERBERT AND ROGER W. PORTELL ...... 303 Latitudinal gradients in body size and maturation of Berryteuthis anonychus (Cephalopoda: Gonatidae) in the northeast Pacific JOHN R. BOWER, JAMES M. MurpHy, AND YASUKO SATO 309 Ultrastructure of muscle-shell attachment in Nautilus pompilius Linnaeus (Mollusa: Cephalopoda) SHINJI IsAs, TOMOKI KASE, KAZUSHIGE TANABE, AND GIVI) AUKGEININYIN" 655 5 65,010 ole Bie eS O ee oo Cie 316 Range extensions of sacoglossan and nudibranch mollusks (Gas- tropoda: Opisthobranchia) to Alaska JEFFREY H. R. GODDARD AND NorRA R. FOSTER ...... 331 Mollusca of Assateague Island, Maryland and Virginia: additions to the fauna, range extensions, and gigantism ROBERT S. PREZANT, CLEMENT L. Counts, II, AND ERIC UC GISUN DUNN Ii cs plderinclicn ey chances ReueH Que aS On eR an ee 337 The century’s finest ID AWIDE ReSIZINDBER Gitar essa saieae er ss cael eehisl ays 356 Anatomical description of Pisidium johnsoni E. A. Smith, 1882 (Bivalvia: Sphaeriidae) from Madagascar A. V. KORNIUSHIN AND J. GERBER .............-.-. 358 AUTHOR INDEX ADIT YAS (Gis oe he oe res doe era eee ae eS (AVELIGANATES IMIG VETS ing or eae Sate iciet eos eee ieee ee amen Baur, B. Bower, J. R. CAZARES, E. EAZZANIGASINE Die tec ea etree Seite a tnd Ea ten een er er CHAPMAN UR Be oars ae eae Ete veo een aac ee CASING 3B 258 ate TO ey een on eee CLEDON, M. GEEVELAND:; (Co Mir. 2 Sete Gio ea peek Uk nee Ne pane ng erate CONTRERAS, H. COUNTSE Cee yee eesiciee et tn OUR SEN EnCana gE eo eae are DE Souza, P. J. S., JR. DETIMANS TON TE. 2a sete te ete eee LT oan DuNCAN, N. EMBERTONS 2 = Gi ser feene ees ne eee 203, 259, EESTEBENET SAS Dees ene ceh ali cet eee eee en eee el Erter, R. J. GES SAU RIWit ican wie oi emcee mae a Po ena lc ey ASL ea ee FOSTER NG IR tage ae chee DT Re Ser as re See FRIED, B. GERBER, J. GopparbD, J. H.R. ....... Se ree nga prieas yescbe ape Nie GOODWINS DAH Are scdee re rue ee en ee arenes TVA NGG Co eos ser aoe oer eee a ar one HERBERT, G. S. HERSHLER, R. Hunt, H. L. Isam, S. JARAMIELO SE 255 cge) 5 cao pr ne aT ee eee ne IKORNIUSHINS Ace Vila ae eo Gece a ere LANDOLFA, M. A. LINDBERG, D. R. TEOCHERS Rie Wicd secace hoe aR es RSE ERS Me ao ee ee See MIATSUSHIRO Ang fa) ilnuse perenne pepe neee eA akon cee eS Page numbers for book reviews are indicated by parentheses. 267 33 224 218 309 261 a 337 33 172 65 MCGRAW, Ris osc a0 so ete lo eral ole Al a ee METCALF; (Aly. sci ics es tee in ee MiVAMOTO. He ei 3 acs ctis aeons Gis seine ee MIYASHITA, T. Murpny, J. M. PARNELL?) Pi Bs i ea avin 3 2 ee Eee PASTORINO;: Gis qc leet ee Doe ee PENCHASZADEH, P. E. PIMENTA;A...D 4 sna oe eo PIZANI3 Ni. We bo oe ae eee PORTELL,, Ri W:.. ). oa Eee eee PREZANT, R. S. QUITON). Be ise in Se eee Raut, S. K. RED; DiGi jis ah a DA ee Rex, A. C. REX, MLAS ao So es eee SCHEIBLING, R. E. SCHONE, Bs Re hiss 0 Se eee oe SHERMA, J. SHIGENO,.'S.. se dwacs oh a ee SISSON, C. G. SQUIRES; ReVs. ose sis. we ee eee STUART, C. T. TAKAGI, R. TANABE!) Ki. 22 8 coe feed eee ee THOMPSON; FIGs 3 ears on ee eee 264, THOMPSON, J. C. TOLL; Re soc bis aoe til onto TROWBRIDGE, C. D. UWEHIVAMA,. Ks. eos 3.8,.408 2 ee ee VALDES, Aine soos, ek ld Se Cee WYLIE, J. MAMAMOTO;, Mi... gc. aie oc) chee eee C= HO | Ve Tiss ee" aE LIGCER A Quarterly published by CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. Berkeley, California R. Stohler (1901-2000), Founding Editor ISSN 0042-3211 Volume 45 January 2, 2002 Number 1 CONTENTS Northeastern Pacific sacoglossan opisthobranchs: natural history review, bibliography, and prospectus ONAN IETUAGID) FER © WB RUC Bo rrats ctseveliaye (ith reps tale ui adente cate) etree ges eS) -4a/4 Gi legalions ekesile es 1 Trogloconcha, a new genus of larocheine Scissurellidae (Gastropoda: Vetigastropoda) from tropical Indo-Pacific submarine caves TOMOR IKAGE ANID YAGSUINONOINANG) 556500 5cbapoob sn eou sounds uaouhusseeoaoe D5 Reproductive cycle of the bivalves Enszs macha (Molina, 1782) (Solenidae), Tagelus dombeti (Lamarck, 1818) (Solecurtidae), and Mulinia edulis (King, 1831) (Mactridae) in southern Chile Maria H. AVELLANAL, EDUARDO JARAMILLO, ELENA CLASING, PEDRO QUIJON, AND FA ERATHD Of CONMRERAS HY meseuiraituad atta aveetie lente as, cre Sith am Usca kee ele le aia. So latar glace Sees Seias 33 Sclerochronology and growth of the bivalve mollusks Chione (Chionista) fluctifraga and C. (Chionista) cortezi in the northern Gulf of California, Mexico BERND R. SCHONE, Davip H. GOODWIN, KARL W. FLEssA, DAvib L. DETTMAN, AND JPYSITIEIR 1D), ROKOPANTATRIOND S/O. agasnA tty eaves ena Re Hed Ge lees PUP a co ean a 45 The influence of hunger and olfactory cues on the feeding behavior of the waved whelk, Buccinum undatum on the blue mussel, Mytilus edulis I OLINE SANGO MPSONM arrricee ne lomn on tes Nolny Us ence Oeil Sea teate ts mua a Ieee cues Gy ay dice ee ws 55 Larval development, precompetent period, and a natural spawning event of the pectinacean bivalve Spondylus tenebrosus (Reeve, 1856) JP TES). JRANRGNTRIEIL) is co ahem Seid och ee ere Al ttle aN eI ae Mp em a en SR Pa ae en 58 CONTENTS — Continued The Veliger (ISSN 0042-3211) is published quarterly in January, April, July, and October by the California Malacozoological Society, Inc., % Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105. Periodicals postage paid at Berkeley, CA and additional mailing offices. POSTMASTER: Send address changes to The Veliger, Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105. THE VELIGER Scope of the journal The Veliger is an international, peer-reviewed scientific quarterly published by the Cali- fornia Malacozoological Society, a non-profit educational organization. The Veliger is open to original papers pertaining to any problem connected with mollusks. 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Send manuscripts, proofs, books for review, and correspondence regarding editorial matters to: Dr. Barry Roth, Editor, 745 Cole Street; San’ Francisco,,CA 94175) "USA. © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). THE VELIGER © CMS, Inc., 2002 The Veliger 45(1):1—24 (January 2, 2002) Northeastern Pacific Sacoglossan Opisthobranchs: Natural History Review, Bibliography, and Prospectus CYNTHIA D. TROWBRIDGE Department of Zoology, Hatfield Marine Science Center, Oregon State University, Newport, Oregon 97365, USA; trowbric @ucs.orst.edu Abstract. The species richness and geographic ranges of the sacoglossan (synonym: ascoglossan) opisthobranch fauna have been well characterized for northeastern Pacific shores, particularly in the Californian province, but the natural history and ecology of these gastropods have been comparatively less well studied. Over half of the described sacoglossan genera and approximately two-thirds of the families are represented on northeastern Pacific shores. At least 25 species of sacoglossans occur: eighteen species are known stenophagous herbivores, and one feeds on opisthobranch eggs. Eight species occur on cold-temperate northeastern Pacific shores, 19 species inhabit the Gulf of California and warm-temperate to tropical Pacific shores, and four species occur in the Aleutian, Oregonian, Californian, and Panamic provinces. Five of the species have been studied appreciably more than the others: Elysia hedgpethi (Marcus, 1961), Alderia modesta (Lovén, 1844), Placida dendritica (Alder & Hancock, 1843), Aplysiopsis enteromorphae (Cockerell & Eliot, 1905), and Stiliger fuscovittatus Lance, 1962. The paucity of study on other species is not necessarily due to low abundance. This natural history review of the regional sacoglossan fauna synthesizes the scattered literature about the stenophagous gastropods and highlights the major gaps that malacologists should seek to fill in the study of this highly specialized order. Future research should focus more on the autecology, population ecology, and community ecology of sacoglossans. Recent advances in isotope analysis, fluorometry, larval culturing, and molecular techniques provide challenging oppor- tunities to enhance our understanding of sacoglossan biology. INTRODUCTION Sacoglossan (synonym: ascoglossan) opisthobranchs are small sea slugs that are suctorial feeders on marine algae, seagrass, diatoms, and opisthobranch eggs (Williams & Walker, 1999). Our knowledge of the northeastern Pacific sacoglossan fauna is quite recent, with a rapid prolifera- tion in species recognized since 1960 (Figure 1). Many of the northeastern Pacific species that are broadly dis- tributed were first described in other parts of the world (Figure 1) and then subsequently recorded as present on northeastern Pacific shores. The rate of species discovery is still high (e.g., Farmer, 1996; Lance, 1998; J. Goddard, personal communication, 2000; Valdés & Camacho- Garcia, 2000). Whether such finds are due to (1) locating easily overlooked species (i.e., problem of omission), (2) previous lack of study (Lee & Foster, 1985), or (3) es- tablishment of introduced species is not entirely clear. Most of the recent discoveries have been in the Panamic province. Beeman & Williams (1980:309) astutely noted: “‘Stud- ies of California opisthobranchs to date have been mainly taxonomic and distributional in nature.”’ In addition, not only is classification within the order Sacoglossa highly unstable (Roller, 1970a; Marcus, 1982; Gascoigne, 1985; Jensen, 1996; Burn, 1998; Williams & Walker, 1999; Mikkelsen, 1998) but also the proper name of the order and several species are controversial (Keen, 1973; Jensen, 1991; K. B. Clark, personal communication, 1986; Mar- shall & Willan, 1999). There remains a continued division in usage of the terms Ascoglossa vs. Sacoglossa; the con- troversy has been exacerbated by numerous prominent authors switching terms between papers and, in at least one case, within papers. After extensive discussions with taxonomists, I now change from my past use of Asco- glossa to Sacoglossa. Despite the taxonomic and nomen- clatural issues, however, in the last two decades, our knowledge of northeastern Pacific species has substan- tially matured with studies on the ecology, ecophysiology, and reproductive biology of sacoglossan slugs. The order has recently been reviewed from a number of different perspectives: feeding ecology (Williams & Walker, 1999), kleptoplasty (Clark et al., 1990; Clark, 1992; Williams & Walker, 1999), population ecology (Clark & DeFreese, 1987), and taxonomy (Jensen 1996, 1997; Mikkelsen, 1998). For many geographic regions, there are admirable syntheses of the sacoglossan fauna, their biology and ecology. The present paper (1) synthe- sizes the existing, broadly scattered details, (2) highlights an unpublished M.A. thesis (Case, 1972) on Stiliger fus- covittatus cited only once (by Behrens, 1980) in the past three decades, and (3) evaluates our present understand- ing of the northeastern Pacific sacoglossan assemblage. Because of these objectives, some of the topics in this Page 2 25 --@- In World —4— NE Pacific 20 15 10 Cumulative Number of Northeastern Pacific Species 0 1825 1850 1875 1900 1925 1950 1975 2000 Date of First Record Figure 1. Temporal pattern of species discovery and/or descrip- tion for northeastern Pacific sacoglossans. Open circles represent first records, for other parts of the world, of species now known from northeastern Pacific shores; closed triangles represent first records of northeastern Pacific species on these shores. Data based on Cockerell & Eliot, 1905; Agersborg, 1923; MacFarland, 1924, 1966; O’ Donoghue, 1924; Pilsbry & Olsson, 1943; Sowell, 1949; Hand, 1955; Marcus, 1961; Keen & Smith, 1961; Lance, 1962; Marcus & Marcus, 1967, 1970a, b; Keen, 1971; Sphon, 1971; Sphon & Mulliner, 1972; Ferreira & Bertsch, 1975; Oakes, 1979; Behrens, 1991a; Valdés & Camacho-Garcia, 2000; J. God- dard, personal communication, 2000. review (e.g., phenology) are necessarily based on person- al communications, observations, or unpublished data by professional colleagues; quantitative descriptions and ex- perimental underpinnings will be (or should be) published in due course. Finally, this review does not attempt to clarify the taxonomic identities of the undescribed species or to resolve issues of problematic species. The primary objective is to provide a cohesive understanding of past work and to provide a focused prospectus for future sa- coglossan research. TAXONOMIC RICHNESS The number of species, termed “‘species richness,”’ varies depending on the author and the specific range consid- ered. McDonald (1975) listed seven species for the cen- tral California coast, Ricketts et al. (1985:562) mentioned “seven or eight species on our coast’’ and provided some early references for the Pacific coast, and Beeman & Wil- liams (1980) provided excellent descriptions of two spe- cies and briefly mentioned four other species on Califor- nian shores. Farmer (1980) provided comprehensive sum- maries of nine species for the northeastern Pacific, incor- porating the Gulf of California species, and Keen (1971) summarized the species on tropical eastern Pacific shores. Behrens (1991a, b) illustrated and briefly described 12 species and mentioned one other. If these records are The Veliger, Vol. 45, No. 1 merged, there are at least 25 species (20 described, five undescribed) on northeastern Pacific shores between Alaska and Baja California, including the Gulf of Cali- fornia (Table 1). With increased study of low latitude northeastern Pacific shores (Mexico to northern Ecuador), more species will undoubtedly be discovered. In terms of higher-level taxonomic diversity, Jensen (1996) listed nine families, 23 genera, and approximately 200 species worldwide in the order Sacoglossa. Based on Jensen’s (1996) classification system, there are an esti- mated 66.7% of the families represented, 60.9% of the genera, and 12.5% of the species in the northeastern Pa- cific region. Depending on the specific boundaries rec- ognized between biogeographical provinces (Vermeij, 1978; Hartman & Zahary, 1983), the species richness varies (Table 1). There are substantially more sacoglos- sans known from the Panamic Province (Gulf of Califor- nia and northeastern Pacific, from Bahia Magdalena south) than from the northern provinces. GEOGRAPHIC RANGES Our knowledge of the geographic ranges of these species (Tables 2, 3) is incomplete, owing to gaps in sampling and, in some cases, a lack of sampling outside known ranges. Bertsch (1973:51) noted: “‘The ranges probably reflect the concentration of study in a few areas as much as the actual ranges of the species.”’ The vast majority of reports on northeastern Pacific sacoglossans are listed as “range extensions,” implicitly indicating increases in Known ranges. Such records should not be considered “range extensions”’ in the strictest sense because there is no evidence that species are modifying their ranges but rather our knowledge of the ranges is changing (Clark, 1997); malacological terminology is presently inconsis- tent with other fields (e.g., population ecology and inva- sion biology) and thus subject to confusion. All of the species found on cold-temperate and boreal shores (Oregonian and Aleutian Provinces) are also found in the Californian Province; four of these species also occur in the Gulf of California (Panamic Province) (Table 1). With the possible exception of the seemingly uncom- mon Aplysiopsis oliviae, Placida sp. 1, and Olea hansi- neensis, most of the other Pacific coast species are widely distributed in the northeastern Pacific. The southern ex- tent of the ranges of species found in the Gulf of Cali- fornia is generally not well known; this undoubtedly re- flects the paucity of opisthobranch studies on low-lati- tude, northeastern Pacific shores. Three species have curious and perhaps questionable ranges: Ercolania fuscata, E. boodleae, and Stiliger fus- covittatus. (1) Ercolania fuscata occurs on northwestern Atlantic shores (Clark, 1975), the tip of South America, possibly southeastern Australia (Thompson, 1973; but see Jensen & Clark, 1983), and the Gulf of California; as Ferreira & Bertsch (1975) emphasized, this distribution C. D. Trowbridge, 2002 Page 3 Table | Sacoglossan opisthobranchs on northeastern Pacific shores. Classification based on Jensen (1996). Cylindrobulla cali- fornica Hamatani, 1971, is not included because Jensen (1996) excluded the family Cylindrobullidae from the order Sacoglossa (but see Mikkelsen, 1998). Provinces based on Vermeij (1978) and Hartman & Zahary (1983). Species SUBORDER OXYNOACEA (SHELLED SLUGS) FAMILY OXYNOIDAE (REDUCED SHELL SLUGS) Oxynoe panamensis Pilsbry & Olsson, 1943 Lobiger souverbii Fischer, 1856 FAMILY JULIIDAE (BIVALVED SLUGS) Berthelinia chloris (Dall, 1918) Julia thecaphora (Carpenter, 1857)! SUBORDER PLAKOBRANCHACEA SUPERFAMILY PLAKOBRANCHIOIDEA (PARAPODIA-BEARING SLUGS) FAMILY PLAKOBRANCHIDAE Elysia hedgpethi Marcus, 1961 Elysia sp. 1 of Behrens (1991) Elysia diomedea (Bergh, 1894)? Elysia oerstedii Morch, 1859 Elysia vreelandae Marcus & Marcus, 1970 SUPERFAMILY LIMAPONTIOIDEA (CERATA-BEARING SLUGS) FAMILY POLYBRANCHIIDAE Polybranchia viridis (Deshayes, 1857)° Cyerce orteai Valdés & Camacho-Garcia, 2000 FAMILY HERMAEIIDAE Aplysiopsis enteromorphae (Cockerell & Eliot, 1905)* Aplysiopsis oliviae (MacFarland, 1966) undescribed species> Hermaea vancouverensis O’ Donoghue, 1924 Hermaea hillae Marcus & Marcus, 1967 FAMILY LIMAPONTIIDAE Alderia modesta (Lovén, 1844) Ercolania boodleae (Baba, 1938) Ercolania fuscata (Gould, 1870) Olea hansineensis Agersborg, 1923 Placida dendritica (Alder & Hancock, 1843) Placida sp. | of Behrens (1991) Stiliger fuscovittatus Lance, 1962 Stiliger sp.° Stiliger sp.’ Total Number of Species Aleutian Oregonian Californian Panamic Province Province Province Province x xX x x x Xx? x x x Xx? XxX? x x x x x x x x x x? x x x x XxX x x x x x xX x x x x x x x x x X x x x x xX x 6-8 8 12-13 18-19 '(Synonym: J. equatorialis Pilsbry & Olsson, 1944) based on Williams & Gosliner (1973). ? Name change by Gosliner (1995). 3 Synonym: Phyllobranchillus viridis (Deshayes, 1857). 4 Not enteromorphea as listed in MacFarland, 1966 (see Marcus & Marcus, 1967; Behrens, 1991a). > Found by M. Chamberlain in southern California (D. Behrens, personal communication, 2000). ° Found by Lance & Farmer in the Gulf of California on Codium magnum (Farmer, 1996; Lance, 1998; D. Behrens, personal communication, 2000). 7 Found by Jeff Goddard in the Gulf of California on C. fragile (J. Goddard, personal communication, 2000). ? Reflects the uncertainty in dividing lines between biogeographic provinces (see Hartman & Zahary, 1983). is rather unusual. It may indicate the species’ introduction along historical trade routes (Ferreira & Bertsch, 1975) or cryptic species (Burn, 1998; Ellis, 1999; Burn, person- al communication to Ellis, 2000). (2) Ercolania boodleae is common on Japanese shores (Baba, 1938; Usuki, 1977; Trowbridge, personal observations) but was only recently reported in the Gulf of California (Farmer, 1980; Behrens, 1991a). This pattern is symptomatic of a recent species The Veliger, Vol. 45, No. 1 Table 2 Distribution of common sacoglossans on northeastern Pacific shores Species Locations Elysia hedgpethi Alderia modesta Aplysiopsis enteromor- phae Hermaea vancouver- ensis Alaska: no records British Columbia: Gibraltar Is., Diana Is., Bordelais Islets, Brady’s Beach, Grapper Inlet near Bamfield, Vancouver Is.; Brentwood Bay, Vancouver Is. Washington: San Juan Is. Oregon: Boiler Bay & Seal Rock, Lincoln Co.; Coos Bay, Coos Co. California: Tomales Bay Oyster Company mudflats & Richardson Bay, Marin Co.; near Redwood Creek & Port of Redwood City, SF Bay; Pebble Beach, Moss Beach, Park’s Point, Pescadero Point, Point Pinos, Monterey Co.; Elkhorn Slough; Shell Beach & Morro Bay, San Luis Obispo Co.; Point Sal, Coal Oil Point, Santa Barbara Yacht Harbor, Carpinteria, Santa Barbara Co.; Flat Rock, Palos Verdes, Los Angeles Co.; La Jolla; Newport Bay, Orange Co. Baja California: Bahia San Quintin, Bahia Tortugas, Bahia de los Angeles, Puertecitos Sonora: Bahia de San Carlos Alaska: Cordova, Prince William Sound* British Columbia: Neroutsos Inlet near Port Alice, Ladysmith, Pachena Estuary, Louie Bay, Esperanza Inlet, Vancouver Is. Washington: Garrison Bay & False Bay, San Juan Island Oregon: Coos Bay and Charleston, Coos Co.; Yaquina Bay, Lincoln Co. California: Freshwater Slough, Park Street Slough, & Park Street marsh in Arcata Bay, Humboldt Co.; Bodega Bay, Schooner Bay, Drake’s Estero, Marin Co.; Bay Farm Is., Alameda Co.; San Fran- cisco Bay; Elkhorn Slough, Monterey Bay; Newport Bay, Orange Co.; San Elijo estuary, Kendall-Frost Marine Reserve and North- ern Wildlife Preserve, San Diego River Flood Control Channel, & Mission Bay, San Diego Co. Baja California: San Quintin Bay Other: North Atlantic shores Alaska: Cutter Rock, Ketchikan British Columbia: Crescent Beach; Gambier Is.; Grappler Inlet, Bamfield, & Esperanza Inlet, Vancouver Is. Washington: Argyll Lagoon, Garrison Bay, Wescott Bay, & Mitch- ell Bay, San Juan Is.; Kayostla Beach Oregon: Boiler Bay & Seal Rock, Lincoln Co.; Neptune Beach & Strawberry Hill, Lance Co.; South Cove, Good Witch Cove, & South Slough, Coos Co. California: Omenoku Pt. & Punta Gorda, Humboldt Co.; Bolinas, Tomales Bay, Bodega Bay; Drake’s Estero, Marin Co.; Duxbury Reef, Marin Co.; Scott Creek, Santa Cruz Co.; Elkhorn Slough, Monterey Bay; Cayucos, Hazard Canyon, & Shell Beach, San Luis Obispo Co.; Leo Cabrillo Beach State Park, Los Angeles Co.; Point Sal, Santa Barbara Co.; San Diego; La Jolla Bay, New- port Bay, Orange Co.; Dead Man’s Bay, San Pedro Baja California: Bahia de los Angeles, Bahia San Quintin Sonora: Bahia de San Carlos Alaska: Humboldt Harbor, Shumagin Islands; Spruce Cape, Kodiak Is.; Cutter Rock & Blank Is., Ketchikan British Columbia: Port Hardy & Newcastle Is., Vancouver Is.; Satu- rina Is. & Flat Top Is. Washington: Kayostla Beach Oregon: Boiler Bay & Seal Rock, Lincoln Co.; North Cove, Coos Co. California: Bodega Harbor & Coleman State Beach, Sonoma Co.; Duxbury Reef, Marin Co. Baja California: No records References Lance (1961, 1966), Marcus (1961), Steinberg (1963), MacFarland (1966), Farmer (1967), Sphon & Lance (1968), Greene (1970a, b, c), Roller (1970b), Goddard (1973, 1984), Green & Mus- catine (1972), Gosliner & Williams (1973), Williams & Gosliner (1973), Behrens & Tuel (1977), Millen (1980), T. Gosliner in Behrens (1991a), Lance (1998), C. Trowbridge (unpublished data) Hand (1955), Hand & Steinberg (1955), Steinberg (1963), Gosliner & Williams (1973), Williams & Gosliner (1973), Belcik (1975), Thompson (1976), McLean (1978), S. V. Millen (1980, personal com- munication, 2000), J. God- dard (1984, personal commu- nication, 2000), Jaeckle (1984), Trowbridge (1993c), Lance (1996), Krug (1998b), Krug & Manzi (1999), W. Farmer (personal communica- tion, 1999) Cockerell & Eliot (1905), Gon- or (1961), Lance (1961, 1998), Marcus (1961), Stein- berg (1963), MacFarland (1966), Sphon & Lance (1968), Roller & Long ’ (1969), Gosliner & Williams (1970, 1973), Greene (1970a), Williams & Gosliner (1973), Belcik (1975), S. V. Millen (1980, 1989, personal communication, 2000), J. Goddard (1984, 1987, person- al communication, 2000), Jaeckle (1984), Behrens (1991a) Trowbridge (1993a, d, personal observations), God- dard et al. (1997), Lance (1998) O’ Donoghue (1924), Sowell (1949)**, Steinberg (1963), Williams & Gosliner (1973), S. V. Millen (1980, 1983, personal communication, 2000), Goddard (1984), Fos- ter (1987), T. Gosliner in Behrens (1991a), Goddard et al. (1997), Trowbridge (per- sonal observations) C. D. Trowbridge, 2002 Species Placida dendritica Stiliger fuscovittatus Olea hansineensis Table 2 Continued Locations Alaska: Bertha Bay, Chichagof Is. B.C.: Triangle Is., Diana Is., Grappler Inlet, Brady’s Beach, Port Renfrew, Bamfield, Vancouver Is.; Mills Bay near Victoria Washington: Kayostla Beach; Cattle Point, San Juan Island Oregon: Boiler Bay, Yaquina Head & Seal Rock, Lincoln Co.; Strawberry Hill, Lane Co.; South Cove, Good Witch Cove, & Squaw Is., Coos Co.; S.H. Boardman State Park, Curry Co. California: Palmer’s Pt. & Trinidad Bay, Humboldt Co.; Bodega Head, Sonoma Co.; Duxbury Reef, Marin Co.; Richardson Bay, Marin Co.; Fort Barry Docks, SF Bay; Punta Gorda, Humboldt Co.; Carmel Bay, Park’s Pt., Pescadero Point, Point Pinos, & Cy- press Point, Monterey Co.; Shell Beach & Morro Bay, Pismo Beach, San Luis Obispo Co.; Flat Rock, Palos Verdes, Los Ange- les Co.; Newport Beach and Newport Bay, Orange Co. Baja California: Isla San Benito; Bahia San Quintin, Bahia de los Angeles Sonora: Bahia de San Carlos Other: Japan, north Atlantic, Australasia, South Africa*** Alaska: Cutter Rock, Ketchikan B.C.: Flat Top Islands (Saturina & Bath); Porlier Pass near Galiano Is.; Stubbs Is. near Telegraph Cove, & Sooke Harbour, Vancouver Is. Washington: San Juan Island Oregon: Seal Rock, Lincoln Co.; Isthmus Slough, Coos Bay, Coos Co. California: Arcata Bay & Humboldt Bay, Humboldt Co.; SF Yacht Harbor, Fort Barry, Sausalito, Marin Co.; Morro Bay Docks & Shell Beach, San Luis Obispo Co.; San Diego & Mission Bays Baja California: Bahia de los Angeles Other: Sebastian Inlet Jetty & Indian River Lagoon at Titusville, Florida Alaska: Cordova, Prince William Sound* British Columbia: Tuwanek Pt., Sechelt Inlet; Sooke Harbour & To- fino, Vancouver Is. Washington: Jaekle’s Lagoon & Garrison Bay, San Juan Is. & Brown Is. & Parks Bay, Shaw Is. Oregon: No reports California: San Clemente Is. * New records in preparation: J. Goddard (personal communication, 2000). ** Sowell’s (1949) record of Hermaea vancouverensis probably refers to Placida dendritica; this inference is based on the superficial similarity of the two species, the fact that P. dendritica was not recognized on northeastern Pacific shores until the 1960’s (MacFarland, 1966; Long, 1969), the author’s familiarity with the site in Oregon, and perhaps most importantly because the algal host was specified to be the green alga Bryopsis corticulans, not the colonial diatom Isthmia nervosa. I do not agree with Belcik’s (1975) interpretation that the record was Aplysiopsis enteromorphae (as A. smithi) because of difference in size, color, tidal level, and algal food. Page 5 References Sowell (1949)**, MacFarland (1966), Long (1969), Gosli- ner & Williams (1970), Greene (1970a), Marcus & Marcus (1970a), Roller (1970b), Greene & Muscatine (1972), Goddard (1973, 1984, 1987, 1990), McLean (1976), Williams & Gosliner (1973), Lambert (1976), Thompson (1976), S. V. Millen (1980, personal communication, 2000), Jaeckle (1984), Gosli- ner (1987), Behrens (199 1a, 1998), Trowbridge (199 1a, b, 1995, 1998a, b, 1999, unpub- lished data), Ichikawa (1993) Goddard et al. (1997), Lance (1998), O’Clair & O’ Clair (1998) Lance (1962, 1966), Steinberg (1963), Roller & Long (1969), Gosliner & Williams (1970), Case (1972), Williams & Gosliner (1973), S. V. Mil- len (1980, 1989, personal communication, 2000), Jensen & Clark (1983), Jaeckle (1984), Clark & DeFreese (1987), Trowbridge (1994, un- published data), Clark (1995), J. Goddard (personal commu- nication, 2000) Agersborg (1923), Gonor (1961), Steinberg (1963), Hurst (1967), Crane (1971), Robilliard (1971), Millen (1980), R. McPeak & D. Mulliner in Behrens (1991a), J. Goddard (personal commu- nication, 2000) *** May be sibling species (C. Trowbridge, work in progress). introduction, although additional evidence (e.g., confirm- ing the species identity) is needed to support this hypoth- esis. (3) The appearance of the northeastern Pacific Sti- liger fuscovittatus in Indian River Lagoon, Florida (Jen- sen & Clark, 1983; Clark, 1995) seems also to be due to an anthropogenic introduction, particularly as this species feeds on filamentous red algae (Polysiphonia) commonly growing on ship hulls, floating docks, floats, and other “artificial’’ surfaces. Chapman & Carlton (1991) suggested a number of cri- teria to evaluate whether a species was native or intro- duced. All three of the above cases may represent cases of introductions, although, based on their criteria, addi- tional information is needed. When Marcus (1961) first Page 6 The Veliger, Vol. 45, No. 1 Table 3 Distribution of the less common species of northeastern Pacific sacoglossans Species Locations References Oxynoe panamensis Lobiger souverbii Berthelinia chloris Julia thecaphora Elysia vreelandae Elysia oerstedii Elysia sp. 1 Elysia diomedea Polybranchia viridis Cyerce orteai Aplysiopsis oliviae Placida sp. | Hermaea hillae Stiliger sp. Ercolania boodleae Baja California: Espiritu Santo Is., Candelero Bay; near La Paz Other: Bocas Is., Province of Bocas del Toro, Panama Baja California: Espiritu Santo Is., Candelero Bay; Playa Maria & Isla San Jose, Baja del Sur Nayarit, Mexico: Santa Cruz Galapagos: Flamingo Cove, Floreana Island, Galapagos Islands Other: Indian, Pacific, and Atlantic Oceans Baja California: Bahia Ballenas & La Paz; Punta Abreojos; La Paz; Puerto Ballandra Bay; Magdalena Bay; Espiritu Santo Is., Cande- lero Bay, Gulf of California Galapagos: Flamingo Cove, Floreana Island, Galapagos Islands Baja California: La Paz Mexico: Socorro Is. Other: Panama, Colombia, Ecuador, Peru Sonora: San Agustin = El Sahuaral Costa Rica: Puntarenas Baja California: Magdalena Bay Baja California: West of Isla Cerralvo; Islas San Francisco, Espiritu Santo, & Cerralvo; Bahia Las Cruces; Bahia Carisalito; Bahia de Concepcion; Bahia de los Angeles; San Marcus Is., Gulf of Calif.; Puerto Lobos; San José Is. Sonora: Puerto Penasco El Salvador: Pacific coast Other: To Panama Panama: Venado Isl., off Ft. Kobbe; Deale Beach (Ft. Kobbe Beach), Canal Zone Baja California: Punta Norte, Isla Cerralvo; Rancho Notri Puerto Escondido, Bahia de Palmas, Punta Colorada, Pulmo Reef, Cabo Pulmo Nayarit: Punta Mita Other: Duncan Is. & Flamingo Cove, Floreana Is., Galapagos; Less- er Antilles; Florida; Panama Costa Rica: Playa Cabuya, Cabuya, Cobano, Puntarenas; Estacion San Miguel, Reserva Natural Absoluta de Cabo Blanco, Cabuya, Cobano, Puntarenas; Playa Ocal del Pefion, Santa Teresa, Cébano, Puntarenas British Columbia: Saltspring Is. & Brentwood Bay, Vancouver Is. California: Duxbury Reef, Marin Co.; Cabrillo Pt. & Pt. Pinos, Monterey Bay; Santa Barbara Channel, Santa Barbara Co. California: San Diego Bay Sonora: Puerto Penasco Baja California: Bahia San Quintin California: Mission Bay Sonora: Puerto Penasco Other: Japan Pilsbry & Olsson (1943), Smith (1961), Doty & Aguilar-San- tos (1970), Lewin (1970), Keen (1971), Williams & Gosliner (1973) Marcus & Marcus (1967, 1970a), Keen (1971), Sphon (1971), Sphon & Mulliner (1972), Baba (1974), Larson & Bertsch (1974), Jensen (1983), Jensen & Clark (1983), Clark & DeFreese (1987), Gosliner (1987), Ichikawa (1993), Gosli- ner et al., (1996) Keen & Smith (1961), Smith (1961), Kay (1964), Keen (1971), Sphon & Mulliner (1972), Williams & Gosliner (1973), Behrens (1991a) Pilsbry & Olsson (1944), Keen (1971), Williams & Gosliner (1973) Marcus & Marcus (1970a, b) Keen (1971) T. Gosliner in Behrens (1991a) Bergh (1894), MacFarland (1924), Marcus & Marcus (1967), Dushane & Sphon (1968), Trench et al. (1969), Bertsch (1971, 1973), Keen (1971), Bertsch & Smith (1973), Williams & Gosliner (1973), Ireland & Faulkner (1981), Debelius (1996), Bertsch et al. (1998) Marcus & Marcus (1967, 1970a), Sphon & Mulliner (1972), Bertsch & Smith (1973), Ferreira & Bertsch (1975), Clark (1995), Debel- ius (1996) Valdés & Camacho-Garctia (2000) MacFarland (1966), Lee & Bro- phy (1969), Gosliner & Wil- liams (1970), Williams & Gosliner (1973), Millen (1980) J. Hamann in Behrens (1991a) Marcus & Marcus (1967) Farmer (1996), Lance (1998), D. Behrens (personal commu- nication, 2000) Baba (1938, 1949), Baba & Ha- matani (1952, 1970), Usuki (1977), W. Farmer (1980, per- sonal communication, 1999), J. Hamann in Behrens (1991a) C. D. Trowbridge, 2002 Page 7 Table 3 Continued Species Locations References Ercolania fuscata Sonora: near Puerto Penasco Other: Florida, northwestern Atlantic Clark (1975, 1995), Ferreira & Bertsch (1975), Jensen & Clark (1983), Clark & DeFreese (1987), Jensen (1988), references therein described Elysia hedgpethi, he considered whether it might have been introduced, given its occurrence on a mudflat in close proximity to mariculture facilities (Pa- cific oysters) in Tomales Bay, California; after comparing the species to congeners around the world, he concluded that it was a separate species. Soon after its initial de- scription in 1961, E. hedgpethi was reported to be wide- spread (to the north and south); thus, this species exem- plifies an overlooked native that differs from geographi- cally distant endemic species (e.g., from the Japanese E. Japonica, the European E. viridis, etc.). PREY SPECIES AnD FEEDING Diets Sacoglossans are traditionally considered to be ste- nophagous consumers with comparatively specialized host-plant associations (see Williams & Walker, 1999). For 76% of the northeastern Pacific species, the feeding habits have been generally well characterized, at least to the generic level (Table 4). Difficulty or unresolved tax- onomy within some algal groups (e.g., Vaucheria, Cla- dophora, Chaetomorpha) as well as malacologists’ in- experience with distinguishing algal species (e.g., Codium and Polysiphonia) have hindered progress in this area. For Hermaea hillae, Elysia sp. 1, E. oerstedii, and Cyerce orteai, prey species have not been described. Radulae of many species have been illustrated (O’Donoghue, 1924; Hand & Steinberg, 1955; Gonor, 1961; Lance, 1962; Marcus & Marcus, 1970b; Ferreira & Bertsch, 1975; Gascoigne, 1975; Farmer, 1980; Bleakney, 1989, 1990; Behrens, 1991b; Valdés & Camacho-Garcia, 2000). Jensen (1980, 1993, 1996, 1997) hypothesized that tooth shape is directly related to food type. Jensen’s re- sults may assist in determining the diets of the poorly studied species; such extrapolation would be a useful tool for future study of uncommon sacoglossans. Furthermore, Bleakney (1989, 1990) and Jensen (1996, 1997) have re- ported intraspecific variation in radular tooth morphology in two species on different diets; it would be intriguing to know whether this phenomenon also occurs in Aply- siopsis enteromorphae, Elysia hedgpethi, and other north- eastern Pacific species that feed on two or more genera of algae. The feeding ecology of northeastern Pacific sacoglos- sans has been investigated experimentally for only a few species: Placida dendritica (Trowbridge, 1991a, b, 1992a, b, 1993b, 1997, 1998a, b), Elysia hedgpethi (Trowbridge, unpublished data), Aplysiopsis enteromorphae (Gonor, 1961; Trowbridge, 1993a), Stiliger fuscovittatus (Case, 1972), Ercolania fuscata (on Atlantic shores; Clark, 1975; Jensen, 1983), and Ercolania boodleae (on Japa- nese shores; Usuki, 1977). As Williams & Walker (1999) have emphasized, there is considerable room for improve- ment in the experimental and statistical rigor of feeding experiments. For example, for feeding preference exper- iments, some of the needed changes include (1) adequate replication and (2) independence of replicates (individual animals in separate containers making separate and in- dividual choices). For experiments in which groups of animals are maintained on different diets (e.g., Chia & Skeel, 1973), the container or dish is the replicate, not the animals within the dish. For experiments in which groups of animals are placed in a single arena with a pairwise choice of algal species (e.g., Jensen, 1983), the individual slugs are not independent and thus cannot con- stitute replicates. If experiments involve measuring prey mass loss due to slug herbivory, negative controls should be included in order to measure the endogenous mass loss in the absence of herbivory. Peterson & Renaud (1989) describe the statistical methodology required to test for significant preferences between pairwise choices; multi- ple-choice experiments are fraught with statistical peril despite their clear biological significance. Even with the best-studied associations, slug discrim- ination among, preference of, and performance on con- generic algal species have not been resolved. For exam- ple, Placida dendritica exhibits distinct feeding prefer- ences among three algal hosts on Oregon shores (Bryop- sis corticulans, Codium fragile, and C. setchellii) (Trowbridge, 1991a); on northeastern Pacific shores, there are at least six potential host species, yet there is no in- formation on whether P. dendritica consumes C. ritteri in Alaska, C. cuneatum, C. hubbsii, or C. johnstonei in southern California, or C. magnum and allies in the Gulf of California. Similarly, many authors report that Sziliger fuscovittatus consumes Polysiphonia pacifica, Polysi- phonia sp., and Callithamnion sp. (Lance, 1962; Stein- Page 8 Table 4 The Veliger, Vol. 45, No. 1 Adult diets described for northeastern Pacific sacoglossan opisthobranchs. In many cases, it is unclear if authors are reporting their own observations of diets or merely reiterating previous reports. Species Diets Description of prey References Oxynoe panamensis Lobiger souverbii Berthelinia chloris Elysia hedgpethi Elysia diomedea Elysia vreelandae Polybranchia viridis Aplysiopsis enteromorphae Aplysiopsis oliviae Hermaea vancouverensis Alderia modesta Olea hansineensis Placida dendritica Placida sp. | Stiliger fuscovittatus Stiliger sp. Stiliger sp. Ercolania boodleae Ercolania fuscata Caulerpa sertularioides, Halimeda (Caulerpa racemosa, C. brachypus, C. paspaloides, C. serrulata)* Caulerpa racemosa, C. sertularioides Codium fragile, C. setchellii, Bryopsis corticulans Padina and perhaps Spyridia Codium Caulerpa racemosa Cladophora columbiana, C. trichoto- ma, Chaetomorpha linum, C. aerea, Urospora, Rhizoclonium Griffithsia pacifica, Polysiphonia hen- dryi Isthmia nervosa Vaucheria spp. Precuthona, Haminoea, Melanochla- mys, Gastropteron, Archidoris, Her- missenda, Dendronotus Codium fragile, C. setchellii, Bryopsis corticulans, (Derbesia, Codium spp., Caulerpa lentillifera, or Hali- meda cuneata)* Cladophora** Polysiphonia pacifica, Polysiphonia brodiaei, P. paniculata, and Calli- thamnion sp.*** Codium magnum Codium fragile Chaetomorpha, Cladophora (Ulva, Enteromorpha, Boodlea)* Cladophora, Chaetomoprha, (Clado- phoropsis, Bryopsis)* coenocytic green algae coenocytic green algae coenocytic green algae coenocytic green algae brown algae coenocytic green algae coenocytic green algae filamentous green algae red algae diatom xanthophyte opisthobranch eggs coenocytic green algae filamentous green algae red algae coenocytic green algae coenocytic green algae filamentous green algae filamentous green algae Doty & Aguilar-Santos (1970), Lewin (1970), Keen (1971) Sphon & Mulliner (1972), Baba (1974), Clark & Busacca (1978), Jensen (1983), Clark & DeFreese (1987), Gosliner (1987), Ichikawa (1993) Kay (1964), Sphon & Mulliner (1972), Marcus & Marcus (1970a) MacFarland (1966), Millen (1980), C. Trowbridge (un- published data) Bertsch & Smith (1973) Marcus & Marcus (1970b) Bertsch & Smith (1973) Gonor (1961), Greene (1968, 1970a), Millen (1980), God- dard (1984, 1987), Trowbridge (1993a), Lance (1998) Millen (1980) Williams & Gosliner (1973), Foster (1987) Hand (1955), Hand & Steinberg (1955), Millen (1980) Hurst (1967), Crane (1971), Robilliard (1971), Millen (1980) MacFarland (1966), Long (1969), Greene (1970c), Roll- er (1970b), Williams & Gosli- ner (1973), Lambert (1976), McLean (1976), Millen (1980), Gosliner (1987), Bleakney (1989, 1990), Beh- rens (1991a), Trowbridge (1991a, b, 1992a, b), Ichika- wa (1993) Oakes (1979) Lance (1962), Steinberg (1963), Beeman & Williams (1970), Case (1972), Clark & Busac- ca (1978) Farmer (1996), Lance (1998) J. Goddard (personal communi- cation, 2000) Baba (1938, 1949), Baba & Ha- mantani (1952, 1970), Usuki (1977), photograph in Beh- rens (1991a) Clark (1975), Jensen (1983), Clark & DeFreese (1987) * Algae in brackets are on Japanese shores (Baba, 1938, 1949, 1974; Ichikawa, 1993), northwestern Atlantic shores (e.g., Clark, 1975; Jensen, 1983; Jensen & Clark, 1983; Clark & Busacca, 1978), or South African shores (Gosliner, 1987). “ Collected on alga; not sure what it feeds on (D. Behrens, personal communication, 2000) but see Oakes (1979). photographed on M. coulteri in the original species description (Lance, 1962) and in Behrens (1991a). C. D. Trowbridge, 2002 berg, 1963; Beeman & Williams, 1980). Case (1972), however, reported that S. fuscovittatus ate three species in San Francisco Bay: P. pacifica, P. brodiaei, and P. paniculata. Given that there about 17 species of Polysi- phonia reported for California, many of which have rec- ognized varieties, it would be intriguing to know how many algal species actually can be used as host species for S. fuscovittatus. Clark (1994, 1995) hypothesized that sacoglossans are particularly vulnerable to environmental or anthropogenic changes, owing to their apparent depen- dence on specific host plants. Little is known, however, to what extent other algal species can serve as alternate hosts. A related issue is whether sacoglossans are stenopha- gous at the local scale but more polyphagous at the re- gional scale (see discussion by Fox & Morrow, 1981). This could occur if diet specificity is affected by devel- opmental processes (e.g., induction of specific digestive enzymes or tooth morphology by initial diet). Recent work on a European sacoglossan (Trowbridge & Todd, 1998, 2001) indicates that the algal substratum used to induce larval metamorphosis does affect subsequent feed- ing preferences of post-metamorphic juveniles. The role of genetic variation in feeding preferences has not yet been examined but may contribute to regional variability in diet; extensive work on suctorial insects, the terrestrial analog of sacoglossans, has demonstrated the importance of genetic mechanisms (see, for example, Trowbridge, 1991a; Trowbridge & Todd, 2001). Particularly surprising is the paucity of information about how native sacoglossans have responded to intro- duced potential hosts. For example, although the invasive pest alga C. fragile ssp. tomentosoides has occurred in San Francisco Bay, California since 1973 (Silva, 1979), and the alga is a potential host for Placida dendritica and Elysia hedgpethi, there have been no published studies on temporal changes in host-plant use with the appearance of a new host plant on Pacific shores. The issue has been investigated on northwestern Atlantic shores (Clark & Franz, 1969; Clark, 1975; Bleakney, 1996), northeastern Atlantic shores (Trowbridge & Todd, 1998, 2001), and Australasian shores (Trowbridge, 1995, 1999). Analogous work is being done on Australian and Mediterranean shores with sacoglossans attacking introduced species of Caulerpa. With the appearance of Caulerpa taxifolia (“killer algae’) in San Diego, California, such issues be- come more pressing. Finally, a few cases of slug-algal associations have been reported which may not be related to feeding. For example, Elysia hedgpethi is often found either crawling on or depositing its egg masses on the green alga Ulva or red foliose algae (e.g., Steinberg, 1963; MacFarland, 1966; Behrens & Tuel, 1977). Aplysiopsis enteromorphae in high tidepools selects Mastocarpus papillatus (= Gi- gartina papillata) for this purpose (C. Trowbridge, per- sonal observation), and conspecifics on mudflats often oc- Page 9 cur on the green alga Enteromorpha (which the slugs do not eat, despite the slug’s species name; Gonor, 1961). Although the significance of the following has not been generally investigated, Case (1972) reported that eggs of Stiliger fuscovittatus develop faster when deposited on algal hosts than on glass or loose in seawater. I have also observed slugs clustering on or under non-food macroal- gae, presumably to ameliorate desiccation stress during daytime low tides. Finally, experimental work on a Eu- ropean sacoglossan has demonstrated that larvae will set- tle and metamorphose on non-host species (Trowbridge & Todd, 2001), and Krug (2001) has documented an anal- ogous situation with larval Alderia modesta in California. While we must be careful in inferring trophic associations from the presence of a slug on a particular alga (as em- phasized by Jensen), field observations of slugs on algae are important and may reflect either trophic associations or previously overlooked, non-trophic aspects of slug bi- ology. Foraging and Feeding Behavior Comparisons of the sacoglossan literature to that of generalist gastropods and other herbivorous invertebrates (e.g., Hawkins & Hartnoll, 1983) reveal major gaps of study in the sacoglossan field; Williams & Walker (1999) noted gaps as well. At least six key issues have not been explored for northeastern Pacific sacoglossans: (1) Frequency of feeding. (2) Presence of temporal feeding patterns. (3) Extent of long and short-range chemoreception of prey species. (4) Importance of algal physiological condition. (5) Ecological effects of slug grazing. (6) Energetics of slugs. With respect to the first topic, observational data are mea- ger, and quantitative data are lacking (Williams & Walker, 1999). The northeastern Pacific Olea hansineensis re- portedly feeds periodically a few times per day (Crane, 1971), whereas Elysia hedgpethi feeds continuously (Greene, 1970c). Graves et al. (1979) reported that the digestive lumina of Alderia modesta contain chloroplasts, suggesting that the species feeds “‘regularly,’’ whereas the kleptoplastic Elysia chlorotica feeds only periodically. The frequency of feeding is difficult to observe directly, given the small size of sacoglossans and the ventral lo- cation of the mouth. Regarding temporal patterns, two-day feeding experi- ments with Placida dendritica, Elysia hedgpethi, and Aplysiopsis enteromorphae indicate no clear distinctive tidal or diurnal periodicity (see Trowbridge, 1991a, b, 1993a, b). Weaver & Clark (1981) reported that Atlantic species with functional chloroplasts oriented toward light, whereas aposymbiotic species avoided light. If this pat- tern were general, then most northeastern Pacific species Page 10 The Veliger, Vol. 45, No. 1 Table 5 Type of chloroplast retention of northeastern Pacific sacoglossans. Species with melanic pigmentation generally lack functional kleptoplasty (Clark et al., 1990). Melanic Species pigment Type of kleptoplasty References Oxynoe panamensis — short-term non-functional retention Muscatine & Greene (1973), Clark et al. (1990) Lobiger souverbii — short-term non-functional retention Clark et al. (1990) Berthelinia chloris — short-term non-functional retention Muscatine & Greene (1973), Clark et al. (1990) Julia thecaphora — short-term non-functional retention Clark et al. (1990) Elysia hedgpethi — short-term (< 12 h) functional re- Greene (1970a, b, c), Greene & Musca- tention tine (1972) Elysia diomedea — functional retention Trench et al. (1969) Polybranchia viridis — short-term non-functional retention Clark, personal observations in Clark et al. (1990) Aplysiopsis enteromorphae ot short-term non-functional retention Clark et al. (1990); but see Greene (1970a) Alderia modesta — short-term (< 12 hr) functional re- Graves et al. (1979), Clark et al. (1990) tention Placida dendritica — intermediate non-functional reten- McLean (1976), Greene & Muscatine tion (1972), Clark et al. (1990) Ercolania fuscata el no retention Clark et al. (1990) (Table 5) should avoid light or perhaps be nocturnal be- cause of the general lack of functional kleptoplasty. Rig- orous experiments and field observations are needed to address this temporal-pattern hypothesis. Although nu- merous studies assert sacoglossan crypsis and suscepti- bility to predators, there is a noteworthy absence of quan- titative data documenting temporal patterns of activity patterns for northeastern Pacific slugs. Similarly, for most intertidal species, it is not known whether slugs feed dur- ing emergence and/or submergence. Elysia diomedea moves around actively during the day at rates up to 9.5 cm minute"! and feeds underwater (Marcus & Marcus, 1967; Bertsch & Smith, 1973). Alderia modesta moves around on Vaucheria mats in the daytime (Trowbridge, 1994), although night observations have never been made. Slugs burrow into the algal mats with increased emergence time, particularly on warm or bright days (Trowbridge, 1994), and thus appear to be active primar- ily during submergence. The role of chemoreception in host-plant location for post-metamorphic slugs and for competent veliger larvae has not been explored for northeastern Pacific species (but see Krug & Zimmer, 2000). Jensen (1982, 1988) in- vestigated the mode of chemoreception for tropical spe- cies in Florida, but research on Pacific shores is needed. Limited observations suggest that Olea hansineensis moves “‘randomly”’ across mudflats, locating opistho- branch eggs by chance or perhaps by extremely short- ranged perception (Crane, 1971). In contrast, the extreme- ly rapid recruitment of Placida dendritica to algal trans- plants on Oregon shores (Trowbridge, 1992a, b, 1998b) suggests that larvae have extremely acute long-distance host detection. Den Hartog (1959) reported that Alderia modesta reacted to chemical stimuli from algal food; in contrast, Aplysiopsis enteromorphae and Ercolania bood- leae do not react when presented with cell sap of their algal food (Gonor, 1961; Usuki, 1977), indicative of little, if any, chemoreception. Ercolania fuscata exhibited a positive response to algal homogenates (Jensen, 1988), although the nature of the compounds was not identified nor was the effective distance defined over which the cues operated. Until we know the nature of the cues inducing larval metamorphosis of sacoglossans and the degree of speci- ficity of such cues (see Krug, 2001; Krug & Manzi, 1999; Krug & Zimmer, 2000a, b), we will not be able to un- derstand fully the extent of the stenophagy of the slugs. For example, it has traditionally been assumed that larval metamorphosis of sacoglossans (and for most opistho- branchs) occurs only in response to prey species of the adults. In laboratory experiments with the Atlantic Elysia viridis, however, competent larvae metamorphosed on a variety of macroalgae species, including host and non- host algae (Trowbridge & Todd, 1998, 2001). Further- more, for northeastern Pacific Alderia modesta, some lar- vae in every lecithotrophic clutch metamorphose imme- diately with no inductive cue, whereas the remaining lar- vae delay metamorphosis indefinitely until either encountering Vaucheria, or dying (Krug, 2001, personal communication, 2000). In terrestrial herbivore-plant interactions, the nitrogen status, stress level, and physiological condition of the C. D. Trowbridge, 2002 plants strongly affect herbivory of stenophagous and po- lyphagous herbivores (reviewed by Trowbridge, 1998b); in marine associations, however, comparable information is generally lacking for intraspecific variation in herbiv- ory. The two notable exceptions are experimental studies with Placida dendritica. First, Trowbridge (1998b) re- ported that desiccation-stressed algal hosts were attacked more frequently by P. dendritica than were unstressed thalli on Oregon (and New Zealand) shores. The basis was not improved food quality or attractiveness to adult slugs; the apparent mechanism was that exudates from stressed algal hosts induced higher rates of settlement and metamorphosis to competent larvae than did exudates from unstressed hosts (Trowbridge, 1998b). Second, Trowbridge (1991a) found that adult slugs exhibited no preferences between mechanically damaged and undam- aged algal tissue but did grow faster on algae damaged by grazing conspecifics. Williams & Walker (1999) reviewed the ecological ef- fect of slug herbivory on algal populations. Presumably, species that do not retain functional chloroplasts cause more grazing damage than species that supplement their nutrition with endosymbiosis or kleptoplasty. To what ex- tent do northeastern Pacific sacoglossans have functional chloroplast retention or kleptoplasty? Most northeastern Pacific species retain chloroplasts for varying lengths of time, but only three species have functional retention (A/- deria modesta, Elysia hedgpethi, and Elysia diomedea) and it is short-term for the first two (Table 5). The phe- nomenon of kleptoplasty has been well reviewed (Clark et al., 1990; Clark, 1992; Williams & Walker, 1999). Yet, details for the majority of Pacific species are lacking or are extrapolated from other geographic regions. Based on the information available, most northeastern Pacific spe- cies are strictly heterotrophic, and thus their herbivory may be more important in damaging their host plants than species with multiple modes of nutrition. Aspects of feeding behavior that have been well stud- ied in one species, Placida dendritica, are the patterns and ecological consequences of gregarious feeding (Long, 1969; Clark, 1975; Trowbridge, 1991b). On the algal host Codium setchellii, 97.4% of the slugs are group members on Oregon shores; on C. fragile, 60.3% of slugs are group members; on Bryopsis, slugs do not generally aggregate (Trowbridge, 1991b). Gregarious feeding and intraspecific feeding facilitation documented for P. den- dritica are unusual in sacoglossans and even in marine herbivores (Trowbridge, 1991b). Sacoglossan herbivory may substantially reduce algal host populations when slug densities and/or per capita feeding rates are high. For northeastern Pacific species, graz- ing by Placida dendritica and Stiliger fuscovittatus may be ecologically important to Codium and Polysiphonia popu- lations, respectively (Case, 1972; Trowbridge, 1992a, 1993b, 1998b). Case (1972:59) remarked that a “‘large population of S. fuscovittatus apparently can reduce the volume of Page 11 Polysiphonia to such a degree that food becomes a lim- iting factor.” The role of epiphytes in determining patterns of saco- glossan attack of host plants has not been well explored. Wahl & Hay (1995) reported that epiphytes could either enhance herbivore attack (“‘shared doom’’) or decrease it (“‘associational resistance”’). For Placida dendritica, algal hosts of Codium fragile with the epiphyte Ceramium co- dicola (specific to Codium) were more attractive than hosts free of epiphytes (Trowbridge, 1993b). This may be due to several different processes: (1) epiphytes provide slugs a refuge from predators, (2) epiphytes ameliorate physical conditions (e.g., desiccation stress during emer- gence and wave force during submergence), (3) slugs at- tack hosts whose defenses are compromised by epiphytes, and (4) red algal epiphytes may induce larval settlement and metamorphosis (Trowbridge, 1993b). Of the north- eastern Pacific sacoglossan species, only two are known to consume epiphytes, namely Hermaea vancouverensis that feeds selectively on the epiphytic diatom J/sthmia nervosa that coats intertidal macrophytes in summer and fall, and Stiliger fuscovittatus that eats epiphytic (and non-epiphytic) species of Polysiphonia. Given the impor- tant ecological roles epiphytes may have in mediating slug—host associations, the ecological function should be explored more fully for different sacoglossans. In terms of sacoglossan energetics, there has been little comprehensive work for any northeastern Pacific species, although there are data for different aspects for different species. The general equation for the energy budget of an organism is: Consumption = Production + Fecundity + Respiration + Excretion + Secretion. There have been several studies that have provided esti- mates of feeding rates for Olea, Alderia, Placida, and Aplysiopsis (Crane, 1971; Trowbridge, 1991a, b, 1992a, 1993a, b). There have been a few calculations from per capita feeding rates to population estimates of slug her- bivory (Trowbridge, 1992a, 1993a, b). Activity levels and respiration have not been explored for northeastern Pa- cific species (but see work by Clark, 1975 on Atlantic Placida dendritica and Ercolania fuscata); fecundity val- ues (section below) are scarce. Thus, there is insufficient information even for the most abundant sacoglossans to determine energetics. Because sacoglossans are suctorial stenophagous feeders, extrapolations from generalist con- sumers would provide unrealistic estimates. REPRODUCTION, DEVELOPMENT AND GROWTH Reproduction Mating and spawning have been documented for several northeastern Pacific species (Gonor, 1961; Seelemann, 1967; Page 12 Baba & Hamatani, 1970; Crane, 1971; Case, 1972; Ferreira & Bertsch, 1975; Millen, 1980; Trowbridge, 1992b, 1993d). The minimum size of mating individuals is suprisingly small. For example, Olea hansineensis forms courtship groups when 2 mm long, and reproduction commences at 4 mm (Crane, 1971; Chia & Skeel, 1973). In Stiliger fus- covittatus, the minimum size of egg mass production is 3 mm (Case, 1972). Mating generally involves paired copulatory behavior typical of most opisthobranchs. Al- deria modesta, however, inseminates conspecifics hypo- dermically (Hand & Steinberg, 1955), as do Ercolania boodleae (Baba & Hamatani, 1970) and E. fuscata (Gas- coigne, 1978). Fertile eggs are produced at least 10 days after copulation for Stiliger fuscovittatus (Case, 1972), although the generality for other species is not known. Like other opisthobranchs, sacoglossans store sperm ob- tained from mating partners; the longevity of these allo- sperm is not known. Opisthobranch allosperm and ova are mixed during egg mass deposition (reviewed by Had- field & Switzer-Dunlap, 1984) but specific information for sacoglossans is lacking. Chia & Skeel (1973) and Seelemann (1967) have re- ported high fecundity values for Olea hansineensis and Alderia modesta, respectively. For example, A. modesta produces about 1000 eggs per day on European shores. On Californian shores, young adults of A. modesta lay approx. one egg mass per day over a 2 to 3 week period in the laboratory; furthermore, there was no difference in the frequency of clutch production for planktotrophic vs. lecithotrophic clutches (P. Krug, personal communication 2000). Case (1972) reported much lower values for Sti- liger fuscovittatus: about 212—232 eggs per day. Egg mas- ses have been described for several species (Gonor, 1961; Lance, 1962; Hurst, 1967; Greene, 1968; Chia, 1971; Case, 1972). Deposition of the masses (oviposition) is usually on the host plants or other macroalgae in the habitat (e.g., Gonor, 1961: Lance, 1962; Greene, 1968; Case, 1972). In con- trast to juveniles and adults, the egg masses, embryos, and larvae do not contain chloroplasts (Greene, 1968; Trench et al., 1969; Case, 1972; Trowbridge, personal ob- servations); thus, retained chloroplasts are newly acquired by each generation. Over 80% of egg masses laid by Sti- liger fuscovittatus were produced between 11 pm and 8 am (Case, 1972). The generality of nocturnal deposition is not known. With the exception of lecithotrophic Alderia modesta (Krug, 1998b), all species have small ova with mean di- ameters between 55 and 95 wm (Table 6). In most cases there is one ovum per capsule; the four exceptions are Lobiger souverbii, Elysia diomedea, E. hedgpethi, and Stiliger fuscovittatus (Table 6). Case (1972) reported that none of the embryos with two ova per capsule developed for S. fuscovittatus. Three other embryonic details are particularly noteworthy. (1) Embryonic development was 10% faster when egg masses were attached to algal hosts The Veliger, Vol. 45, No. 1 than when attached to glass or floating freely in seawater (Case, 1972). (2) Embryonic synchrony occurs within in- dividual egg masses of S. fuscovittatus (Case, 1972). (3) Hatching rates vary between 95% and 99% for S. fus- covittatus (Case, 1972). The generality of these patterns merits further investigation for other northeastern Pacific sacoglossans. Of the northeastern Pacific species for which data are available, all but one have planktotrophic larvae (Table 6); Alderia modesta is poecilogonous and produces both planktotrophic and lecithotrophic larvae (Krug, 1998a, b, 2001; Krug & Zimmer, 2000a). Veligers and shells have been described by Hurst (1967), Greene (1968), Case (1972), Goddard (1984), and Krug (1998a, b). The larval types of the majority of warm-temperate to tropical spe- cies have not yet been described. Overall, information on development is available for only half of the known northeastern Pacific species (Table 6). Larval Development and Metamorphosis Strathmann (1987) reviewed larval attributes of north- eastern Pacific sacoglossans. None of the species has been raised through its life cycle with the exception of Alderia modesta from southern California (Krug, 1998a, 2001; Krug & Manzi, 1999; Krug & Zimmer, 2000a, b) and from Europe (Seelemann, 1967) and Aplysiopsis entero- morphae (P. Krug, personal communication, 2000). In fact, only a few sacoglossan species with planktotrophic larvae have been successfully raised through their lengthy larval growth period to larval competency, settlement, and metamorphosis (e.g., Krug & Zimmer, 2000); nu- merous other attempts have failed (e.g., Case, 1972; Trowbridge, unpublished data). This area of research re- quires more attention, particularly in terms of the rates of larval growth and the nature and specificity of cues in- ducing larval settlement and metamorphosis. Larvae of A. modesta responded to water-soluble algal cues as well as surface-associated compounds (Krug & Manzi, 1999; Krug & Zimmer, 2000a; Krug, 2001). The little quanti- tative experimental data on sacoglossans (Trowbridge & Todd, 2001) indicate that the paradigm of metamorphosis only in response to adult prey is a significantly over-sim- plistic view based in large part on insufficient controls to test alternative hypotheses (see Havenhand, 1991; Trow- bridge & Todd, 2001). The spatial and temporal patterns of sacoglossan re- cruitment have not been extensively examined, particu- larly at the regional scale. On a local scale (e.g., at a given site), Placida dendritica recruited more abundantly to algal hosts transplanted to (1) wave-sheltered coves than on closely adjacent points (Trowbridge, 1992a), (2) desiccation-prone microhabitats than to low-stress ones (Trowbridge, 1998b), and (3) horizontal substratum than to closely adjacent vertical substratum (Trowbridge, un- published data). Peak recruitment rates are 200—400 slugs C. D. Trowbridge, 2002 Developmental features of northeastern Pacific sacoglossans Page 13 Table 6 Ovum Ova Shell length diameter per at hatching Veliger Species (wm) capsule (wm) type References Lobiger souverbii (54.6—66.5)* Up to 5 no data type I Clark & Goetzfried (1978), Clark & Jensen (1981) Elysia hedgpethi 70 1-2 99, 109 type I Greene (1968), Strathmann 105 + 20.6 (1987), J. Goddard (person- al communication, 2000) Elysia diomedea no data 6-14 no data no data Bertsch & Smith (1973) Aplysiopsis enteromorphae 66-70 1 107-113 type I Gonor (1961), Greene (1968), OS s2"iley/ Goddard (1984), Strath- mann (1987) Aplysiopsis oliviae no data 1 no data no data Millen (1980) Hermaea vancouverensis no data 1 no data type I Trowbridge (unpublished data) Alderia modesta 68-80 1 90-124 type I Hand & Steinberg (1955), (70—82)* Hurst (1967), Thompson (1976), Clark & Goetzfried (1978), Strathmann (1987), Krug (1998b) 105 1 186 (190)* type I Seelemann (1967), Krug (1998b) Ercolania boodleae ? 1 ? qy Baba & Hamatani (1952) Olea hansineensis 81—120 (capsule) 1 110.7 type I Agersborg (1923), Hurst (1967), Strathmann (1987) Placida dendritica no data 1 82-112 type I Greene (1968), Kress (1971), (47-77+)* (113-127)* Clark (1975), Thompson (G24. = Dall) Of = 15:0 (1976), Strathmann (1987) Stiliger fuscovittatus 70-95 G2) 110-150 type I Lance (1962), Case (1972), (66.5)* Clark & Goetzfried (1978), Strathmann (1987) Ercolania fuscata (60, 66.5) no data no data type I Clark (1975), Clark & Goetz- (64.5 + 2.0)* fried (1978), Clark & Jen- sen (1981) (_ )* Indicates from regions other than NE Pacific shores. algal thallus"! month"! (Trowbridge, 1992a). Given that most northeastern Pacific species appear to have plank- totrophic larvae (Table 6), information about the role of nutrient concentrations, phytoplankton concentrations, and upwelling patterns that affect larval survival, growth, and settlement clearly merits attention (e.g., Trowbridge, 1992b). Many sites appear to have high densities of sa- coglossan larvae, not because the benthic algal hosts are more attractive or abundant (Trowbridge, unpublished data) but because of the influence of oceanographic con- ditions on these factors. For example, Seal Rock and Strawberry Hill, Oregon, consistently have high densities of many species of sacoglossans (as well as other opis- thobranchs) every spring and summer (in contrast to what was initially reported by Sphon, 1972); these two sites are recruitment “‘hot-spots’”’ for many types of larvae in- cluding barnacles, mussels, and sacoglossans (Menge, 1992; Menge et al. 1997; Trowbridge, 1992b; B. Menge, personal communication 1996). Such meso-scale ocean- ographic conditions may account for some of the apparent patchiness of sacoglossan populations. Post-Metamorphic Growth Another enigmatic period in sacoglossan life cycles is the post-metamorphic juvenile stage, particularly the be- havior, feeding habitats, and growth rates of juveniles. For Alderia modesta on European shores, juveniles (0.8 mm long) feed, rapidly develop cerata, and produce eggs when 10 days old at a length of 3 mm (Seelemann, 1967). On the shores of southern New England, the life span of A. modesta was estimated as 2—6 months (Clark, 1975): information for northeastern Pacific populations is not available. Information on growth of Olea hansineensis also indicates a rapid life cycle, with 5 days to reach 1 mm and 2-3 weeks to reach sexual maturity (Crane, 1971; Chia & Skeel, 1973). Clark (1975) and Jensen (1983) recorded the growth of Atlantic populations of Er- colania fuscata on multiple algal diets (Cladophora, Page 14 Chaetomorpha, Cladophoropsis). Furthermore, Clark (1975) conducted reciprocal feeding experiments to de- termine the importance of algal source of slugs vs. in- trinsic food quality; he also documented that slugs were, on average, larger on Chaetomorpha on the shore but more abundant on Cladophora. Jensen (1983) also re- corded the growth of Lobiger souverbii on Caulerpa ra- cemosa (on Atlantic shores). Fretter (1941) described the gut of sacoglossans and suggested that species could ingest large quantities in short periods, given the structure of the gut. If high in- gestion corresponds to rapid growth, then sacoglossans have the potential for extremely rapid growth. Based on short-term growth rates of Placida dendritica, slugs in- crease in mass at about 25% body mass per day in the laboratory on Codium spp. and at 30-40% on Bryopsis corticulans (Trowbridge, 1991a). Growth rates in the field were calculated by outplanting algal hosts (with no slugs) and measuring the body size of recruits after different intervals of time (Trowbridge, 1992a). Based on these data, Trowbridge (1991a) estimated the longevity of P. dendritica to be 1—2 months. Case (1972) observed that post-settlement juveniles of Sriliger fuscovittatus pre- ferred new growth (i.e., terminal young branches) of Po- lysiphonia brodiaei to older, highly corticated algae, and he also suggested that juveniles could starve in the pres- ence of host plants, presumably if young branches were not available. S. fuscovittatus reached sexual maturity in less than 2 months after metamorphosis; slugs reproduced for several months, then died (Case, 1972). POPULATION DYNAMICS anp STRUCTURE Seasonality Phenological information for northeastern Pacific sa- coglossans is rather meager. For all the northeastern Pa- cific species, the inferred seasonalities (Figure 2) are based on published collection records, my own collection records (C. Trowbridge, unpublished data), or personal communications (J. Goddard, 2000; S. V. Millen, 2000). More sampling and observations are needed before reli- able phenological data are available for the less well-stud- ied 19-20 sacoglossan species. Collection records for species in the Gulf of California and southward may in- dicate that sacoglossans are present much of the year; quantitative abundance data would assist in the interpre- tation of presence/absence data. The most comprehensive and quantitative data are on Placida dendritica on Oregon shores (Trowbridge, 1992b) where the species occurred on intertidal algal hosts from April to September with occasional slugs be- ing found in March and October (Figure 2). Aplysiopsis enteromorphae also appears to be primarily a spring and summer species on Oregon shores (Goddard, 1984:146, J. Goddard, personal communication, 2000; Trowbridge, 1993a, d). Monthly observations over the course of | year The Veliger, Vol. 45, No. 1 (September 1975 to September 1976) at Scott Creek, San- ta Cruz County, California showed that A. enteromorphae was present year around in high intertidal, outer coast pools; the species peaked in abundance in September and October and declined sharply in November (J. Goddard, unpublished observations). Egg masses were produced year around but were most abundant in September and October (J. Goddard, unpublished observations). The spring and summer seasonality inferred for Elysia hedg- pethi (Figure 2) is based on my observations for Seal Rock and Boiler Bay, Lincoln County, Oregon (C. Trow- bridge, unpublished data). Elysia hedgpethi and its eggs were found on Codium fragile in La Jolla, California in January and February 2000 (J. Goddard, unpublished ob- servations). Finally, Stiliger fuscovittatus in San Francis- co Bay, California was most abundant in fall and early winter (Case, 1972); whether the species exhibits a sim- ilar phenology on open-coast shores is not yet known. Several authors (Miller, 1962: Clark, 1975) have cate- gorized opisthobranchs based on whether they are (1) an- nual to subannual with multiple generations per year or (2) perennial. Based on seasonality data (Figure 3), this dichotomy is difficult to apply to northeastern Pacific spe- cies. Placida dendritica, Alderia modesta, and Stiliger fuscovittatus could be assigned to the first category as they have continual recruitment, rapid growth, and early reproductive maturity (Case, 1972; Trowbridge, 1992a, b, 1993c, d). Aplysiopsis enteromorphae is clearly suban- nual in Oregon with a single generation per year (Trow- bridge, 1993a, d). For other species, there is not sufficient information to categorize them. Some authors have sug- gested that spring to summer seasonal patterns reflect slugs tracking seasonally available algal species. Yet, for P. dendritica, Elysia hedgpethi, A. enteromorphae, A. mo- desta, and S. fuscovittatus, the algal hosts are present all year, and thus, the seasonal disappearance is due to con- straints other than food limitations. For Hermaea vancou- verensis, the diatom /sthmia nervosa is seasonally abun- dant with peak densities from July to September on Oregon open-coast shores (Trowbridge, personal obser- vations) and perhaps earlier in California; spatio-temporal variation in diatom abundance throughout the slug’s range merits examination. Phenological information for three of the northeastern Pacific species, also found on Atlantic shores, is summarized by Clark (1975) and Bleakney (1996); comparable data for Pacific shores are lacking. Sacoglossan Abundance For most northeastern Pacific sacoglossan species, pop- ulation density information is qualitative: abundant, com- mon, frequent, rare, etc. (e.g., Lance, 1961; Steinberg, 1963; Sphon & Lance, 1968; Roller & Long, 1969; Roll- er, 1970b; Williams & Gosliner, 1971; Gosliner & Wil- liams, 1973). Quantitative data are slowly being collect- ed. For pool-dwelling species such as Aplysiopsis enter- C. D. Trowbridge, 2002 Page 15 Species Placida Jan Feb Mar Apr M Nov Dec dendritica Elysia hedgpethi LL _ _ _sSsS_sedld ty Aplysiopsis enteromorphae J Alderia modesta Stiliger fuscovittatus Olea hansineensis Hermaea vancouverensis Aplysiopsis Oliviae G Lanetetsiimea |G ee ae Figure 2. Seasonality of northeastern Pacific sacoglossan species in three major regions: N (north) indicates Alaska to Oregon, S (south) indicates California, and G (gulf) indicates the Pacific coast of Baja California, the Gulf of California, and southward to the equator. Shaded cells represent slug presence and ? represents presumed occurrence but no published reports, personal observations, or personal communications. Data from Bergh, 1894; Cockerell & Eliot, 1905; MacFarland, 1924, 1966; Sowell, 1949; Hand & Steinberg, 1955; Gonor, 1961; Keen & Smith, 1961; Lance, 1961, 1962, 1966, 1996; Marcus, 1961; Smith, 1961; Hurst, 1967; Farmer, 1967; Marcus & Marcus, 1967; Dushane & Sphon, 1968; Lewin, 1970; Sphon & Mulliner, 1972; Bertsch, 1971, 1973; Robilliard, 1971; Sphon, 1971; Bertsch & Smith, 1973; Chia & Skeel, 1973; Gosliner & Williams, 1973; Williams & Gosliner, 1973; Larson & Bertsch, 1974; Ferreira & Bertsch, 1975; Lambert, 1976; Behrens & Tuel, 1977; McLean, 1978; Millen, 1980, 1989; Goddard, 1984, 1987, personal communication, 2000; Jaeckle, 1984; Foster, 1987; Trowbridge, 1993a, d, 1994, unpublished data; Goddard et al., 1997; Bertsch et al., 1998; Lance, 1998. ka N G S G N G S G N S G S S S | omorphae, Trowbridge (1993a) reported values of up to 1993c, d). Lewin (1970) reported that Oxynoe panamensis 50% of pools at individual sites on Oregon shores. For was abundant at about one slug per m*. For sacoglossan mat-dwelling species such as Alderia modesta, population species inhabiting separate, upright branching algal hosts, estimates range from tens to thousands per m* (Trowbridge, estimates of abundance range up to 70% of hosts for Pla- Page 16 Number of Species Ed 0 10 20 30 40 50 60 70 Max. Body Length (mm) Figure 3. Maximum size—frequency distribution of northeastern Pacific sacoglossans. Abbreviations for the larger species are as follows: Ae = Aplysiopsis enteromorphae, Py = Polybranchia viridis, Eh = Elysia hedgpethi, Ed = Elysia diomedea. Data based on Agersborg, 1923; MacFarland, 1966; Marcus & Mar- cus, 1967, 1970b; Baba & Hamatani, 1970: Keen, 1971; Chia & Skeel, 1973; Beeman & Williams, 1980; Goddard, 1984; Beh- rens, 1991a; Trowbridge, 1993a, c; Bertsch et al., 1998; Valdés & Camacho-Garcia, 2000. cida dendritica (Trowbridge, 1993b). Case (1972) report- ed abundance values of Stiliger fuscovittatus in a range of ways: total number of animals found, number of slugs per ml of algal host, and number of slugs per m* of sub- strata. Other authors such as Clark & DeFreese (1987) have reported abundance values as number of slugs per gram dry mass of algae. Dry mass values, however, are not logistically possible for all sites (e.g., marine re- serves) or for all algal hosts (e.g., Vaucheria spp., which forms mats binding algae and sediments together, the di- atom Isthmia nervosa, which forms colonies attached to intertidal macrophytes, or Codium setchellii, which is rel- atively scarce (Trowbridge, 1996)). For none of the north- eastern Pacific species is there sufficient population data to test whether the positive association between latitude and peak slug density (reported by Clark & DeFreese, 1987 for Atlantic species) also occurs in our region. Giv- en that past collection locations are known for most spe- cies (Tables 2, 3), such regional abundance information should be feasible to document. Population Structure Detailed investigations of population structure have been reported for four species: Stiliger fuscovittatus (Case, 1972), Alderia modesta (Trowbridge, 1993d), The Veliger, Vol. 45, No. 1 Aplysiopsis enteromorphae (Trowbridge, 1993a, d), and Placida dendritica (Trowbridge, 1992b). Detailed length- frequency data (e.g., 871 individuals of Stiliger fuscovit- tatus: Case, 1972) can provide valuable insight into the timing of juvenile recruitment, the rate of juvenile and adult growth, and the timing of adult mortality. When supplemented with environmental data (see Trowbridge, 1992b), population structure data can be a powerful tool for investigating sacoglossan ecology. Because many eco- logical processes (e.g., fecundity, predation, etc.) are size- dependent, maximum body size of a given species (Figure 3) is valuable and should be included in future collec- tions. ABIOTIC FACTORS The importance of physical or abiotic factors in structur- ing sacoglossan populations has been generally assumed but rarely demonstrated. Notable exceptions include de- scriptive and experimental work by Case (1972) and Trowbridge (1992a, b). The salinity tolerance of Stiliger fuscovittatus and Alderia modesta presumably affects the spatio-temporal patterns of slug populations within estu- aries. Case (1972) reported that 50% of S. fuscovittatus individuals tested died within 18 hr when held in 10 ppt water and 50% died within 72 hr at 13 ppt; slugs survived well at salinities of 21 and 33 ppt. Given that salinities in San Francisco Bay dropped to 4 ppt for over 24 hr, Case’s suggestion that low salinity caused the dramatic observed decline in slug population density seems well supported. Comparable details have been described for the marsh slug A. modesta on European shores (Seele- mann, 1968). There was geographic variation in salinity tolerance by A. modesta; both high and low salinities dis- rupted embryonic development and egg production (See- lemann, 1968). Presumably, these autecological responses will dictate species’ distributions within bays. Behrens (1980), summarizing the literature for San Francisco Bay, reported that four species occurred in the bay: A. modesta, S. fuscovittatus, Elysia hedgpethi, and Placida dendritica. The salinity tolerance of the latter two species is not known, nor is it known for Aplysiopsis enteromorphae in high in- tertidal pools or on estuarine mudflats (Trowbridge, 1993a, d). The role of fluctuations in air and seawater temperature also merits consideration. Case (1972) reported that adult Stiliger fuscovittatus was eurythermal. Both low temper- ature (4°C) and high (19—23°C) had little effect on adult slugs, despite the narrow temperature range slugs en- countered in the bay (11-16°C) (Case, 1972). Further- more, Trowbridge (1992b) noted that the maximum size of Placida dendritica increased significantly with in- creased seawater temperature. With the availability of temperature chart recorders that could be attached to rocky surfaces on the shores, our understanding of the C. D. Trowbridge, 2002 contribution of atypically hot or cold days to population fluctuations of slugs should improve. Finally, the influence of wave exposure on sacoglossan population structure and dynamics has long been sur- mised. The little information available is mostly indirect. Case (1972) monitored the population abundance of Sti- liger fuscovittatus along a sea wall with a strong wave exposure gradient; slugs were most abundant at site 2 (site 1 was most sheltered, site 8 was most exposed). He surmised that S. fuscovittatus could not persist on the open coast but suggested this hypothesis should be tested experimentally. Other authors, including myself, have subsequently found the species on the open coast, al- though albeit in comparatively wave-protected habitats (e.g., Seal Rock, Oregon where a series of rocks breaks the wave force considerably). Current techniques now available to measure wave force and water flow in a quantitative fashion could be usefully applied to opistho- branch studies. BIOTIC INTERACTIONS Predation Opisthobranchs have a repertoire of defenses against potential predators (e.g., reviews by Thompson, 1976; Di Marzo et al., 1993; Cimino & Ghiselin, 1998; Cimino et al., 1999). For northeastern Pacific sacoglossan species, the support for chemical and/or behavioral defenses is relatively meager (Table 7). Trowbridge (1994) tested the pH of four species of sacoglossans; while they all reduced their surface pH when physically disturbed, only one was acidic (Aplysiopsis enteromorphae). Three of the four species were readily consumed by a suite of ecologically relevant predators in spite of any purported defenses such as cerata waving and/or autotomy. However, one of these, Stiliger fuscovittatus, was not consumed by the carnivo- rous Roboastra tigris (Lance, 1997). Aplysiopsis entero- morphae was also not consumed by a variety of preda- tors, but the basis of the slugs’ unpalatability has not been explored (Trowbridge, 1994) In a 12-day field experiment conducted in Oregon, Al- deria modesta abundance was significantly reduced on exposed algal mats and in cage controls compared to in full predator-exclusion cages (Trowbridge, 1994). These results indicate that intense predation did significantly re- duce slug populations; moreover, observational evidence from Vader (1981) and experimental evidence from Trowbridge (1993c, 1994) indicates that bird, fish, and crab predation can be important in reducing slug densi- ties. Bleakney (1996) suggested that the “‘potent, sickly- sweet perfume exuded” by A. modesta may be an effec- tive defense against spiders, beetles, and bugs; this in- triguing hypothesis merits experimental testing. Predator exclusion experiments need to be conducted for other sa- coglossan species, particularly for the warm-temperate to Page 17 tropical species that may experience more intense pre- dation than their high-latitude counterparts. The tropical to subtropical sacoglossan Elysia diome- dea contains secondary metabolites named tridachione (after the slug’s previous genus name Tridachiella) and 9, 10-deoxytridachione; it is unclear whether these com- pounds are derived directly from dietary sources, from retained functional chloroplasts, or synthesized de novo (Ireland et al. 1978; Ireland & Faulkner 1981). Vardaro et al. (1992) reported that Placida dendritica on Medi- terranean shores produced polypropionate compounds de novo and that they were not localized in specific tissues. Furthermore, Di Marzo et al. (1993) reported that the Mediterranean P. dendritica was unpalatable to fishes; in contrast, Trowbridge (1994) reported that fishes readily consumed specimens on Oregon shores. The source of this variation is intriguing; whether it is due to cryptic species (morphologically similar species that are often confused as a single species), geographic variation in ca- pacity to synthesize compounds de novo, or to other fac- tors is not known. The source of the secondary metabo- lites, however, is seemingly not the algal diet (Cimino et al., 1999). Information on the predation of sacoglossan larvae and egg masses is meager. Caprellid amphipods may prey upon swimming veliger larvae or setting juveniles (Kae- stner, 1967, cited by Case, 1972). There are some details of egg predation by the sacoglossan Olea hansineensis. Crane (1971:58) wrote that ‘“‘adults were observed to re- coil violently from their own egg mass.... Apparently, contact is necessary for recognition of their egg masses.” This aversion response is not only to their egg masses but also to those of conspecifics (S. V. Millen, personal communication, 2000). In all of the cases above, the slugs are consumed di- rectly by predators. Predation, however, can have indirect effects on slugs (Case, 1972) when consumers (e.g., birds) consume the substrata (e.g., mussels) upon which the slugs’ algal food grows. Indirect effects of predators or generalist herbivores would be most important in cases in which the slugs’ algal hosts are epibionts, growing on top of a shellfish or an alga. The importance of this mech- anism in regulating slug populations has not yet been ex- plored. Competition In terrestrial systems, there is extensive theoretical and empirical information on the role of interspecific and in- traspecific competition among stenophagous herbivores such as phytophagous insects. In marine systems, the top- ic has barely been addressed. In many cases, sacoglossans occur on host plants not used by other grazers (Trow- bridge, 1992a). In other cases, such as Aplysiopsis enter- omorphae, the slugs coexist with prosobranch gastropods and small crustaceans (e.g., amphipods, isopods) (Trow- The Veliger, Vol. 45, No. 1 Page 18 (L661) 20UR'T “(h661) 2SPHIQmosy, (6661) ‘Te 19 OUTUTD (F661) PSPLIQMOIL “(EC66T) “Te 19 OZIVI Id ‘(ZH66[1) [eB 19 OTepIeA (OL6]) luReUeH 2 eqrg (9661) Souyeotg “(r661) ISPLIQMOIL (CCH) Slaquingg 2 puey (F661) SSPLIQmoll (1861) Jouxpne,; 7 puryol] “(EZ61) ‘Te 9 purely (L661) 299Ur'T ‘(P661) ISPLIQMoIy, (9661) ‘[v 19 Adu -I]SOD “(L86[) 1OUT[SOD ‘“(P96]) AVY (OL61) Ul -MIT ‘(OL6]) SOIURS-IR[INSY 2 AOG sisi] vAIspoqoy Kq powinsuod jou {sqeio wz soysy oO} a[quie[ed soysy 0} [qe -yeyedun sjeunrue uvoueajyipayy !sqvio a soysy 0} g[quivyed speurtue UosIIO jeep ou sqeio 2 soysy Oo} o]qQeieyed uMOUy JOU ddINOS fsqvid pur soysy oO} 9/qQeIV]eduN {viep ou S1AB1] DAI -spoqoy JO ‘sqeid ‘soysy Aq pouinsuod jou Ys 0} [RYO] UOTIIN9S 91XO} Ysy O} [RYIO] UONDINAS SIxO} SIOUDIOJOY Ayyiquieed [e-anou 0} OIseq WO poqinsip uayM Yd Apog donpa !eIVIID Poys 2 DALAM (y-oueprorid *3'3) oaou ap sayeuoidoidAjod oztsayjuds s]BPWIUe UvoURLIO}Ipsyy ‘[eynou 0} SIseq WO paqimsip uayM Yd Apog donpa. :vIV1Id pays 2 DAPM ping arym-Ay]Iu opnxo [[Ouls JOOMS ATYOIS “eI] -noed ‘orseq [[Hs Inq Hd Apog sonpal ¢ = Hd 0} [eynou wow Yd Apog dsonpar !eIVIID Pays 2 DAvM (aNpOqriewt Arepuosas) duo -1yoeplyAxoap-Q] ‘6 2 QUOTYyOepLy pep ou AUIO}0} -nB dqo] ‘souRISqns dIYM IsIeYSsSIP AulojO Ne Ie} ‘UOT -91998 SIXO} ‘(UIDLIOd| Nes 2 ULdID] -ned) uoNeNsonbas aypoqriou [e3aye sasudjap [enUua}0g SMDIPAOISN AIST] S DILApuap VP1IVD] dq ava]poog VIUDJOIAT DISapoul DIsAPLY apydiowosajua sisdoiskjdy Vapawolp VISA] A 1yjadspay VISA] y NG4IANOS 1I81GOT sisuaupupvd IOUKXE, saroads uvsso[sooesg s1oyepoid 07 Aypiqeivyed .syeurrue oy) puv suvsso[soors oylovg Ula\svayIoU JO suONEIdepe dAIsUuajap [eNUD0g L Ge C. D. Trowbridge, 2002 Page 19 bridge, 1993a). On northeastern Pacific shores, Placida dendritica and Elysia hedgpethi coexist on the same host species and even occasionally on the same thalli (D. Beh- rens, personal communication, 2000; C. Trowbridge, per- sonal observations); whether the two species facilitate one another, inhibit one another, or have no effect de- serves future consideration. Finally, for the two species that often occur at very high densities, P. dendritica and Alderia modesta, intra- specific interactions merit investigation. Trowbridge (1991b) demonstrated that small individuals of P. den- dritica inhibit the feeding and growth of large conspecif- ics (i.e., intraspecific competition); in contrast, large slugs facilitate the feeding and growth of small and large con- specifics (facilitation). For A. modesta, population density and body size are inversely related on a regional scale (Trowbridge, 1993c, d). Whether this pattern reflected in- traspecific competition or other mechanisms (e.g., high recruitment coupled with high mortality) has not been investigated. SPECIES IDENTITY AnD VARIATION The majority of sacoglossans are described based on mor- phology, especially radular tooth shape and size and var- ious attributes of the reproductive system. In few cases has the biological species concept been tested by con- trolled matings of seemingly conspecific animals. Thus, it is frequently difficult to determine whether observed variation is best considered inter-specific or intra-specific. Molecular techniques offer independent methods to test the validity of morphospecies. To date, extremely few molecular studies of this sort have been conducted on sacoglossans (or other opisthobranchs). Theisen & Jensen (1991) investigated genetic variation of European species (including the species Alderia modesta) with allozymes. Krug (1998a, b) and Trowbridge (unpublished data) in- vestigated variation in the mtDNA gene cytochrome ox- idase subunit I (COI) of A. modesta, Placida dendritica, and Ercolania boodleae. Thollesson (1999) and Trow- bridge (work in progress) have sequenced portions of the mtDNA gene 16S rRNA in P. dendritica. I predict that molecular techniques will result in the splitting of cos- mopolitan species (e.g., Placida dendritica) into sibling species, analogous to work on other taxa (e.g., Knowlton, 1993; Geller et al., 1997). P. dendritica has been a con- troversial species for decades (Thompson, 1973, 1976, 1988; Gosliner, 1987; Bleakney, 1989, 1990; Trowbridge, 1997; Burn, 1998; references therein) due to morpholog- ical, physiological, and ecological variation. Molecular details may soon resolve whether P. dendritica is the ap- propriate name for the northeastern Pacific species: the species was described from specimens collected from Torbay, England. Molecular techniques may resolve many of the prob- lematic taxonomic issues as well as assist with the as- signment of new undescribed species to correct genera. The placement of many species in the families Hermaei- dae and Limapontiidae (sensu Jensen, 1996) has been very problematic, rendering the sacoglossan literature dif- ficult to follow. For example, the species Aplysiopsis en- teromorphae has been placed in three different genera since 1905; many other species have been transferred be- tween genera (in different families) as our understanding has improved. Molecular research may assist in resolving future taxonomic difficulties (e.g., with the undescribed species shown in Table 1). Finally, molecular information could contribute substantially to the questions of larval dispersal, gene flow host specificity, and other ecological or evolutionary issues. PROSPECTUS The field of sacoglossan biology is wide open with ex- tensive areas of unexplored issues. Some of the priority areas for future research on northeastern Pacific sacog- lossans are: 1. Investigate the northeastern Pacific sacoglossan fauna from the Gulf of California south to the equator. The investigation of this tropical to subtropical region will undoubtedly raise our estimate of sacoglossan species richness. . Document the population structure and dynamics of species, including the seasonality of slug and spawn occurrence, adult immigration, and frequency of adults over-wintering. If sacoglossans are indeed particularly susceptible to environmental degradation, habitat loss, and anthropogenic change (Clark, 1994), basic popu- lation information about these species is essential to provide a baseline from which to evaluate future change. 3. Document the host-plant associations in more compre- hensive detail, both spatially and temporally. Even specialized associations change on ecological and evo- lutionary time scales. Thus, understanding the condi- tions under which trophic flexibility does occur is bi- ologically significant. 4. Study the feeding and foraging behavior, particularly the existence of any temporal patterns (tidal or diurnal/ nocturnal). Ecological theories about feeding specific- ity are frequently based on assumptions of vulnerabil- ity of slugs to potential predators; basic information about when and where sacoglossans feed is crucial to evaluating their risk to visual predators. 5. Investigate the relative importance of kleptoplastic vs. heterotrophic sources of nutrition. The new technique of PAM fluorometry provides us with the means of rapidly and non-invasively screening slugs for photo- synthetic activity (S. Williams, 2000: personal com- munication, 2000). 6. Quantify patterns of larval growth, metamorphosis, post-larval growth, and fecundity. ii) Page 20 7. Document the effect of physical variables such as sa- linity, temperature, irradiance, turbidity, etc., as well as UV light, pesticides, and other types of coastal pol- lution on slug population dynamics (see Clark, 1975, 1994, 1995). 8. Investigate the patterns of genetic variation within and among species; such molecular techniques will aid the correct placement of the taxonomically challenging, undescribed sacoglossans on northeastern Pacific shores as well as contribute to the understanding of sacoglossan population structure and dispersal. Acknowledgments. This review was supported by the kindness of colleagues and friends. In particular, I thank H. Bertsch, D. Behrens, J. Goddard, B. Rudman, and R. Willan for valuable conversations and letters; D. Behrens, J. Goddard, S. Millen, P. Krug, S. Williams, and B. Roth for their generous and construc- tive comments on a draft of this paper as well as permission to cite unpublished observations; and L. Weber, S. Gilmont, and J. 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Associational resistance and shared doom: effects of epibiosis on herbivory. Oecologia 102:329—340. WEAVER, S. & K. B. CLARK. 1981. Light intensity and color preferences of five ascoglossan (=sacoglossan) molluscs (Gastropoda: Opisthobranchia): a comparison of chloroplast- symbiotic and aposymbiotic species. Marine Behaviour and Physiology 7:297—306. WILLIAMS, G. C. & T. M. GOSLINER. 1971. Notes on the ecology and distribution of opisthobranchiate mollusks of the San Carlos Bay region, Gulf of California. The Echo 3:33. WILLIAMS, G. C. & T. M. GoSLINER. 1973. Range extensions for four sacoglossan opisthobranchs from the coasts of Califor- nia and the Gulf of California (Mollusca: Gastropoda). The Veliger 16:112-116. WILLIAMS, S. I. 2000. “*Plant-Animals”’: a study of sacoglossan sea slugs. PhD Thesis, University of Western Australia, Perth. WILLIAMS, S. I. & D. I. WALKER. 1999. Mesoherbivore-macroal- gal interactions: Feeding ecology of sacoglossan sea slugs (Mollusca, Opisthobranchia) and their effects on their food algae. Oceanography and Marine Biology Annual Review 37:87-128. The Veliger 45(1):25—32 (January 2, 2002) THE VELIGER © CMS, Inc., 2002 Trogloconcha, A New Genus of Larocheine Scissurellidae (Gastropoda: Vetigastropoda) from Tropical Indo-Pacific Submarine Caves TOMOKI KASE Department of Geology, The National Science Museum, Tokyo, 3-23-1 Hyakunincho, Shinjuku-ku, Tokyo, 169-0073, Japan; kase@kahaku.go.jp AND YASUNORI KANO* Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan; kano@kahaku.go.jp Abstract. A new genus Trogloconcha is proposed for Trogloconcha ohashii, sp. nov. within the Larocheinae Mar- shall, 1993, a unique subfamily that lacks an anal slit or foramen among the Scissurellidae (Vetigastropoda). The new species inhabits gloomy to totally dark, shallow-water submarine caves and deep caverns and is distributed widely in the tropical to subtropical eastern Indian and western Pacific oceans. T: ohashii, sp. nov. has papillate cephalic tentacles unlike species of Larochea (the condition is unknown for Larocheopsis), has a small operculum, and does not show sexual dimorphism in shell features unlike species of Larochea and Larocheopsis. One modern species Trogloconcha tesselata, sp. nov. from Okinawa, Japan, and one late Oligocene species Larocheopsis marshalli Lozouet, 1998, from France, both represented by shell alone, are assigned to the new genus. INTRODUCTION Mollusks from submarine caves primarily accessible through SCUBA diving have been investigated in recent years. Submarine cave mollusks have been most exten- sively sampled in the Indo-Pacific Oceans (Kase & Hay- ami, 1992; Hayami & Kase, 1992, 1993, 1996; Kase, 1998a, b, c, 1999; Kase & Kano, 1999; Kano & Kase, 2000) and in the Mediterranean Sea (Di Geronimo et al., 1993, 1997; La Perna, 1998). The investigation of cave mollusks has produced interesting questions, both taxo- nomically and biogeographically. New mollusks of little known and unknown taxa, and many living features of interesting species previously known only as empty shells have been discovered (Kase & Hayami, 1992; Kase, 1998a, b, c, 1999; Kase & Kano, 1999; Kano & Kase, 2000). In this paper, a new genus and two new species of the scissurellid subfamily Larocheinae are described. A total of over 1500 specimens of the new species Trogloconcha ohashii, mostly represented by empty shells, were col- lected from a number of submarine caves, caverns, and crevices in the tropical western Pacific and eastern Indian oceans. The habitats are from 4 m to 51 m in depth, gloomy to totally dark inside, mostly filled with calcare- * Address for correspondence: Department of Geology, The National Science Museum, Tokyo, 3-23-1 Hyakunincho, Shin- juku-ku, Tokyo, 169-0073, Japan ous muddy sand, and may have been formed mostly dur- ing the low sea levels during the late Quaternary. Trog- loconcha tesselata, on the other hand, is known only from empty shells at a single locality. MATERIALS anp METHODS Shell-bearing bottom sediments were collected by hand and/or hand-made sampler and sieved with 0.5 mm mesh. The shells were picked under a binocular microscope. In spite of an abundant occurrence of empty shells, live specimens are rare and are represented only by 13 spec- imens of 7: ohashii. They have been found only in sub- marine caves, and have not been found in nearby shallow- water bottoms outside of the caves, nor have they been recorded from deep waters. It seems, however, that the species is not restricted to cave habitats, but is living in coral rubble deeply embedded in inaccessible sublittoral situations. Live animals were collected by brushing the under-surface of coral rubble on the bottom sediments. In “Cross Hole” of Irabu islet of the Miyako Islands, live specimens were collected, together with a number of live bivalves and gastropods that are associated with patchy colonies of a tube-forming annelid. The bivalves are Cosa waikikia (Dall, Bartsch & Rehder, 1938), Chlamydella in- cubata Hayami & Kase, 1993, Chlamydella tenuissima Hayami & Kase, 1993, etc., which attach to the annelid tubes with byssus. The associated gastropods are scissu- rellids such as Scissurella staminea A. Adams, 1862, and Page 26 undetermined species of Scissurella, Sinezona, and ris- soids. Live animals were relaxed in 7.5% magnesium chlo- ride, fixed in 10% formalin for 24 hours, and preserved in 75% ethanol. For SEM observation of soft parts, ani- mals were gradually dehydrated, transferred to t-butyl al- cohol, and dried with a freeze-drier JEOL JFD-300. Rad- ulae were removed from the buccal mass, soaked in so- dium hypochlorite for several minutes, then washed, mounted, and dried. SYSTEMATICS Superorder VETIGASTROPODA Salvini-Plawen, 1980 Family SCISSURELLIDAE Gray, 1847 Subfamily LAROCHEINAE Finlay, 1927 Genus Trogloconcha Kase & Kano, gen. nov. Type species: Trogloconcha ohashii Kase & Kano, sp. nov. Diagnosis: Shell minute, thin, fragile, umbilicate, later- ally expanded turbiniform, without anal slit or foramen; aperture large, inner lip simple, without internal inner septum; protoconch almost smooth; teleoconch whorls rounded, with reticulate sculpture. Radula rhipidoglossate with formula © + 5 + 1 + 5 + ©; central tooth broadest, lateral 1 broad, laterals 2—4 with slender shafts bowed outwardly near base, lateral 5 with quadrangular broad base, tapered to tip. Operculum rudimentary, with diam- eter of “4 of shell aperture. Animal with papillate cephalic and non-papillate epipodial tentacles, without brood pouch. Gonochoristic, no size differences between sexes. Etymology: The genus name is from the combination of Latin, Troglo (cave) and concha (shell), referring to the habitat of the type species. Discussion: Finlay (1927) established the family Laroch- eidae to accommodate the single species Larochea mir- anda Finlay, 1927, from off northern New Zealand, and tentatively placed the family close to the caenogastropod family Merriidae (= Vanikoridae). Marshall (1993) ex- amined the shells and radulae of Larochea and his new genus Larocheopsis, and correctly placed the taxon as a subfamily of the Scissurellidae. He defined the subfamily as having these characters: (1) a minute, thin, haliotiform- turbiniform teleoconch with fine reticulate (Larochea) or almost smooth (Larocheopsis) sculpture, without anal slit or foramen; (2) a smooth (Larocheopsis) or finely gran- ulate (Larochea) protoconch; (3) a radula with the for- mula~ +5 + 1+ 5 + ~; (4) animal with right ctenidium absent, left ctenidium monopectinate (Larochea); and (5) cephalic and epipodial tentacles non-papillate (Larochea). The new genus Trogloconcha is erected for T. ohashii, nov. as the type species. One modern species T. tes- The Veliger, Vol. 45, No. 1 Table 1 Gonad analysis of Trogloconcha ohashii sp. nov. Shell size is measured maximum shell diameter when shell ap- erture is placed on flat surface. Shell size (mm) Gonad Locality 1.30 testis Miyako island, Japan 1.20 ovary Miyako island, Japan 1.00+ ovary Miyako island, Japan 1.00 ovary Miyako island, Japan 0.75 ovary Saipan selata, sp. nov. from Okinawa, Japan, and one Oligocene species Trogloconcha marshalli (new combination, = Larocheopsis marshalli Lozouet, 1998) from France, both represented by shell alone, are allocated to the new genus on the basis of the overall shell similarity to 7. ohashii. The shell, radular, and ctenidial characters indicate that the new genus is a member of the Larocheinae (Figures 1—3). However, there are some differences that warrant separating 7: ohashii from the other larocheinine species at the generic level. The new genus has a smooth proto- conch like Larocheopsis (Figure 2), but differs from the latter in having reticulate teleoconch ornamentation (Fig- ure 1). In radular morphology, T: ohashii has a fifth lat- eral tooth which is more slender than that of Larochea, and has a first lateral tooth more slender than that of Larocheopsis (Figure 3D). Moreover, T: ohashii has a rudimentary operculum and micropapillae on cephalic tentacles (Figure 3A—C), whereas the operculum is absent in Larochea and Larocheopsis, and the tentacles are not papillate in Larochea (the condition ts unknown for Lar- ocheopsis) (B. Marshall, 1993, personal communication). Reproductive traits further distinguish the new genus. In Larochea, young are brooded in the right subpallial cavity, and the shells exhibit sexual dimorphism: the fe- male has a large internal inner lip septum, whereas there is a small internal inner lip septum in the male. In Lar- ocheopsis, an internal inner lip septum is absent, and the male seems to be smaller than the female and firmly at- taches to the body whorl outside of the parietal area (Mar- shall, 1993). T: ohashii, on the other hand, has neither the internal inner lip septum nor the brooded young in the subpallial cavity, and it lacks the dwarf males on the body whorl of the large female shells. A serial thin sec- tion analysis of the gonads reveals either testis or ovary in fully grown specimens of T. ohashii. Thus, the species is, like Larochea secunda Powell, 1937, and Larochea scitula Marshall, 1993, evidently gonochoristic and has males and females of similar shell size (Table 1). Trogloconcha ohashii Kase & Kano, sp. nov. (Figures 1A—C, 2A, B, 3) Larochea miranda Finlay, Bandel, 1998:66, pl. 33, figs. 3, 4; non Finlay, 1927. T. Kase & Y. Kano, 2002 Page 27 Figure 1. A-C. Trogloconcha ohashii Kase & Kano, gen. et sp. nov. Frontal, apical, and basal views of holotype (NSMT Mo72828), 1.13 mm wide, 0.81 mm high, from “Cross Hole,” Irabu islet, Miyako Islands, Okinawa, Japan. D-E Trogloconcha tesselata Kase & Kano, gen. et sp. nov. Frontal, apical, and basal views of holotype (NSMT Mo72830), 1.1 mm wide, 1.02 mm high, from north of Kohama Island, Yaeyama Group, Okinawa. The Veliger, Vol. 45, No. 1 Figure 2. Protoconchs of Trogloconcha in apical views. A, B. Trogloconcha ohashii Kase & Kano, gen. et sp. nov., holotype, NSMT Mo72828. C, D. Trogloconcha tesselata Kase & Kano, gen. et sp. nov., holotype, MSMT Mo72830. Scale bars = 100 wm for A and C, and 50 pm for B and D. Type specimens: Holotype NSMT Mo72828, 0.81 mm high, 1.13 mm wide; paratypes NSMT Mo72829; para- types MNHM. Type locality: ““Black Hole’ diving site, northwest of Shimoji Island, Miyako Group, Okinawa (24°49.1'N, 125°08.3'E); depth 35 m, totally dark inside; calcareous muddy sand. Distribution: This species is widely distributed in the shallow waters of the tropical and subtropical areas be- tween Cocos Keeling (Indian Ocean) in the west and French Polynesia (western Pacific Ocean) in the east. Other material examined: COCOS KEELING—1 emp- ty shell from sta. CK1, cavern, west of West Island, 12°10.8'S, 96°48.8'E, depth 48.6 m, gloomy. CHRIST- MAS ISLAND (INDIAN OCEAN)—3 empty shells from sta. XM4, ““Thunder Dome” diving site, long cave seem- ingly connected to land cave(s), north of Christmas Is- land, depth 9 m, totally dark. BALI, INDONESIA—20 empty shells, Menjangan Island National Park, south side at ‘“‘Underwater Cave’’ dive site, shallow crevice, depth 25-30 m. BORNEO, MALAYSIA—116 empty shells from sta. CT, “‘Turtle Cavern” diving site, long cave, Si- padan island, Sulu Sea, 118°36.5'E, 05°04.8'N, depth 15 m, totally dark. PHILIPPINES—100+ empty shells from sta. AN4, cavern in front of Vistamar Resort, Anilao, Ba- tangas, 13°45.1’N, 120°55.0’E, depth 40 m, gloomy; 38 empty shells from sta. AN3, ‘““Mapatin Cave” diving site, cave, southwest of Maricaban Island, Batangas, 13°40.2'N, 120°49.0’E, depth 46 m, totally dark; 39 emp- ty shells from ‘‘Marigondon Cave” diving site, huge cave, south of Mactan Island, 10°15.8’N, 123°59.2'E, T. Kase & Y. Kano, 2002 Page 29 4 * ( \ 1 Figure 3. External anatomy and radula of Trogloconcha ohashii Kase & Kano, gen. et sp. nov. A, B. Drawings of a female animal from Saipan, removed from shell. Scale bar = 100 pm. A. Ventral view. B. Dorsal view. Abbreviations: apg, opening of anterior pedal gland; ct, cephalic tentacle; e, closed eye; ept, epipodial tentacle; f, foot; i, intestine; Ict, single left ctenidium; Ism, left shell muscle; m, mouth; mm, mantle margin; op, operculum; ov, ovary; 1, rectum; rsm, right shell muscle; sn, snout; sop, right subocular peduncle; st, stomach. C. SEM shot of extracted animal from Miyako Islands, Okinawa. Note papillate cephalic tentacles and a subocular peduncle. Scale bar = 100 wm. D, E. Radula of a specimen from Miyako Islands, Okinawa. D. Enlargement of central (c), lateral (1—5), inner marginal (m) teeth, scale bar = 5 pm. E. Whole teeth of transverse rows, scale bar = 10 wm. Page 30 depth 27 m, totally dark; 86 empty shells from two cav- erns. Balicasag Island of Bohol, 09°32.7'N, 123°40.7'E, depth 17 m, gloomy. OKINAWA ISLANDS, OKINAWA, JAPAN—112 empty shells from ‘“Shodokutsu”’ (= small cave) diving site, cave, east of Ie islet, 26°42.9'N, 127°50.1'E, depth 20 m, totally dark; 4 empty shells from ‘“‘Daidokutsu”’ (=large cave) diving site, huge cave, east of Te islet, 26°42.9'N, 127°50.1’E, depth 20 m, totally dark. MIYAKO ISLANDS, OKINAWA, JAPAN—43 empty and 3 live shells from ‘‘Cross Hole” diving site, cave, Irabu islet, 24°51.6’N, 125°09.5’E, depth 15 m, gloomy; 3 empty shells from “‘Lunch Hole,” cave in tidal flat, Irabu Islet, 24°51.6'N, 125°10.0’E, depth 4 m, totally dark; 1 empty shell from “‘L-arch” diving site, L-shaped cave, Irabu islet, 24°51.7’N, 125°09.7’E, depth 25 m, to- tally dark; 6 empty shells from “‘Devil’s Palace” diving site, long cave, Shimoji islet, depth approx. 25 m, gloomy; 107 empty shells from ‘‘Witch’s House” diving site, cave, Shimoji islet, 24°49.3'N, 125°08.3’E, depth 35 m, totally dark; 3 empty shells from ‘“‘Toriike”’ diving site, approx. 30 m long tunnel, Irabu islet, 24°49.1'N, 125°08.3'E, depth 12 to 40 m, gloomy. YAEYAMA IS- LANDS, OKINAWA, JAPAN—23 empty shells, north of Kohama Island, 24°21.5'N, 123°58.9'E, depth 15 to 20 m, crevices; 2 empty shells from ‘“‘Sabachi Cave” diving site, Yonaguni Island, totally dark. DAITO ISLANDS (BORODINO ISLANDS), OKINAWA, JAPAN—2 emp- ty shells from *“‘Gon-gon-ana Cave” diving site, cavern, Minami-Daito Island, 25°50.68'N, 131°01.85’E, depth 23 m, gloomy. OGASAWARA ISLANDS (BONIN_IS- LANDS), JAPAN—1 empty shell from cavern, Otouto- jima, gloomy; 2 empty shells from ‘Giant Cave” diving site, cave, Tatejima, totally dark. TINIAN—200+ empty shells from sta. TN1, huge cave close to “‘Tinian Grotto” diving site, 15°01.1'N, 145°35.0’E, depth 50 to 51 m, gloomy. SAIPAN—26 empty shells from “Grotto” div- ing site, cave, Saipan, 15°15.3’N, 145°49.6’E, depth 20 m, totally dark. GUAM—1 empty shell from cavern, Apra Point, 13°27'N, 144°37’E, depth less than 10 m, gloomy. PALAU—100+ empty shells from **Virgin Hole 1,” cave branched from main tunnel in reef lagoon, 07°07.2'N, 134°14.1'E, depth 17 m, totally dark; 5 empty shells from ‘“‘Siaes Tunnel” diving site, huge tunnel, 07°18.7'N, 134°13.6'E, depth 24 to 44 m, gloomy; 55 empty shells from “‘Blue Hole” diving site, huge cave, 07°08.3'N, 134°13.3'E, depth 36 m to 38 m, totally dark. POHNPEI—1 empty shell from sta. POI, “‘Tawag Point” diving site, cavern, 06°53.0'N, 158°06.0’E, depth 26 m; gloomy. NAURU—7 empty shells from sta. NR1, cavern, AW Aiwo, 0°32.5'S, 166°54.5’E, depth 15 to 25.5 m, gloomy. NEW CALEDONIA—3 empty shells from sta. Pins 2, cavern, east of Nuu Powa, Ils des Pins, 22°31.6’S, 169°25.9'E, depth 17 m to 20.9 m, gloomy. VANUA- TU—6 empty shells from ‘*Taj Mahal” diving site, cave, west of Efate Island, 17°38.4’S, 168°08.7'E, depth 15 m to 18 m, gloomy to totally dark. FIJI—1 empty shell from The Veliger, Vol. 45, No. 1 a cavern, north of Ono Island, Great Astrolabe Reef, 18°51.8’S, 178°27.0'W, depth 7 m, gloomy inside. TON- GA—15 empty shells from sta. VV3-13, “Swallows Cave’ diving site, cave, southwest of Falevai Island, Vava’u Group, 18°40.9'S, 174°02.9'W, depth 17 to 18 m, gloomy; 3 empty shells from sta. HA-4, cavern, west of Haano Island, Ha’apai Group, 19°43.1'S, 174°17.4’W, depth 5 m, gloomy. TAHITI—72 empty shells from sta. TH1, TH1-4, “Cave Arue”’ diving site, cave, west of Ta- hiti, 17°30.9'S, 149°32.1'W, depth 22 m to 30 m, gloomy. Description: Shell minute in size, up to 1.34 mm in width, depressed-turbiniform, umbilicate, thin, fragile, opaque white in shell color, with height about %4 of width. Periostracum very thin, colorless. Protoconch smooth, 142 to 176 pm in diameter, tip narrowly rounded, and separated from teleoconch by slightly flared rim. Teleo- conch just two volutions in largest specimen, rapidly ex- panded, evenly rounded and separated by impressed su- ture; end of mature body whorl descending obliquely and steeply. Sculpture of first half whorl fine, sharp, regularly spaced collabral axial riblets, thereafter finely reticulating collabral riblets and fine spiral cords; intersection of both forming tiny tubercles. Umbilicus wide and deep, rim rounded, and sculptured only by axials inside. Aperture large, subovate, steeply prosocline, and not holostomous. Outer lip thin and sharp, parietal area narrow, and inner lip simply concave, thin, and sharp. Operculum rudimentary, multispiral, thin, corneous, with diameter of % of shell aperture (Figure 3B). Radula rhipidoglossate, consisting of approx. 85 trans- verse rows, with formula © + 5 + 1 + 5 + &. Central tooth broadest, enlarging toward base, cutting edge broad and straight, with nine cusps, median cusp largest. Lat- erals of one to four similarly shaped teeth, tightly inter- locked outwardly near base; lateral 1 broader than laterals 2 to 4, cutting area with six cusps, second to innermost cusp longest; lateral 2 with four cusps, also second to innermost cusp longest; laterals 3 and 4 with five cusps, with longest cusp at center; shaft of lateral 5 becomes broader toward base with two angulations projected in- wardly at middle and base, cusp six, fourth to innermost cusp longest, two outer teeth minute. Marginal field of more than 40 teeth in each side of row; teeth very slender, cutting edge subtriangular; innermost tooth with six long cusps. Animal with long cephalic tentacles, closed eyes with short stalks, right subocular peduncle, long epipodial ten- tacles, right and left shell muscles and left ctenidium. Cephalic tentacles and peduncle bear micropapillae. Epi- podial tentacles three on each side, all similar in length. Right shell muscle far larger than left. Left ctenidium monopectinate, with up to 11 leaflets; right ctenidium ab- sent. Rectum terminating as anus near right shell muscle. Sexes separate; no size difference between male and fe- male; brood pouch absent. T. Kase & Y. Kano, 2002 Measurements: Range of diameter of 30 specimens from the Philippines, Okinawa, and Palau, 0.87-1.34 mm (mean 1.06, SD 0.11); range of height (30 specimens), 0.64—-0.94 mm (mean 0.79, SD 0.08); range of height/ diameter ratio (30 specimens), 0.60—0.87 (mean 0.75, SD 0.06); range of protoconch diameter of 33 specimens from Philippines, Okinawa and Palau, 142 wm—176 wm (mean 157, SD 0.8). Remarks: In teleoconch shape and surface sculpture this species resembles the species of the genus Larochea. In addition to the lack of internal inner lip septum, 7. ohash- ui differs from Larochea miranda Finlay, 1927, Larochea secunda Powell, 1937, and Larochea scitula Marshall, 1993, in having a wide umbilicus and a small smooth protoconch (Figures 1A—C, 2A, B). T. ohashii is easily distinguished from Larocheopsis amplexa Marshall, 1993, primarily by the reticulate surface sculpture and presence of a wide umbilicus. The new species is distin- guished from T. marshalli primarily in having a broadly open umbilicus and coarser ornamentation. Both species have a similar meshlike ornamentation over the shell sur- face, but the intersections of the axial and spiral cords are spiny in 7: ohashii, whereas they are not in T. mar- shalli. Etymology: The species is named after Mr. Shu-ichi Ohashi, a professional SCUBA diver from Naha, Okina- wa, Japan, who helped the authors in collecting the ma- terial. Trogloconcha tesselata Kase & Kano, sp. nov. (Figures 1D—F 2C, D) Type specimens: Holotype, NSMT Mo72830, 1.02 mm high, 1.11 mm wide; 7 paratypes, NSMT Mo72831. Type locality: North of Kohama Island, Yaeyama Group, Okinawa (24°21.5'N, 123°58.9'E); depth 15 to 20 m; crevices; coral sand. Distribution: Okinawa, Japan; only known from the type locality. Description: Shell minute in size, naticiform, 1.11 mm in width in largest specimen, anomphalous, thin, fragile, opaque white in shell color, with width slightly greater than height. Spire elevated very slightly from body whorl. Periostracum unknown. Protoconch almost planispiral, smooth except for indistinct granules, about 0.16 mm in diameter, 1.25 in volution, tip narrowly rounded, and sep- arated from teleoconch by slightly flared rim. Teleoconch just two volutions in largest specimen, rapidly expanded, evenly rounded, and separated by weakly impressed su- ture; end of mature body whorl descending obliquely and steeply. Sculpture of first half of teleoconch whorl pro- socline, roundly curved, regularly spaced, sharp, 25 col- labral axial riblets; after % volution teleoconch whorl Page 31 starting to bear spiral cords finer than axial riblets, first on middle of upper surface and adding successively on both sides of first one, finely granulated at intersections of axial ribles. Body whorl round-sided, sculptured with dense and very fine, prosocline axial and spiral cords. Aperture large, subcircular, moderately prosocline and in- terrupted at base of previous whorl. Outer lip thin and sharp, parietal area weakly convex, and inner lip slightly reflected at abaxial end. Soft part unknown. Measurements: Range of shell diameter of eight speci- mens, including holotype, 0.75—1.14 mm (mean 0.91, SD 0.11); height, 0.69-1.02 mm (mean 0.83, SD 0.10); height/diameter ratio, 0.90—0.96 (mean 0.91, SD 0.02). Remarks: This species is represented only by eight emp- ty shells and is known only from the type locality, where it is associated with T: ohashii. It has a smooth proto- conch, and sculpture pattern in the early teleoconch whorl and apertural features almost identical to T. ohashii. T. tesselata has a similar shell form and protoconch mor- phology to those of Larocheopsis amplexa, but the mesh- like sculpture pattern over the teleoconch surface of the new species differs from the shallow pits in the early whorls and spiral threads in the later whorls of the latter species. The allocation of this species to Trogloconcha gen. nov. is based on the greater similarity of the shell to T. ohashii rather than to L. amplexa. Trogloconcha tesselata most closely resembles Trog- loconcha marshalli from the upper Oligocene of France in its overall shell characters, strongly suggesting con- geners for both species. The new species is only separable from T. marashalli in the absence of an umbilicus. It is also distinguishable from T. ohashii in its higher propor- tion of shell form, less steeply inclined outer lip, much finer meshlike ornamentation, and lack of open umbilicus. Etymology: From the Latin, tesselatus (adv.), meaning tesselated with reference to the finely reticulate ornamen- tation of the whorls. Acknowledgments. Many people helped us in collecting the ma- terials: I. Hayami (Kanagawa University), S. Ohashi, S. Kinjo, H. Kinjo, M. Uchima, K. Ogura, M. Taniguchi (Okinawa), J. Cabrera (National Museum, Manila), R. Gibson (Vanuatu), G. Paulay, L. Kirkendale, C. Meyer (University of Florida), Y. Ya- mazaki (Palau), B. Richer de Forges and the captain and crew of R/V Dawa, ORSTOM (New Caledonia), M. Cathrein (Christ- mas Island), D. Gerhard (Cocos Keeling), A. Jimwereiy (Nauru), T. Furuta (Pohnpei), and M. Yasui (Yap). We thank T. Isamu (Division of Marine Resources, Palau), J. Starmer (Coral Reef Research Foundation, Palau), S. Slack-Smith (Western Australian Museum), and D. Slip (Parks Australia, Christmas Island) for their assistance in obtaining research permits. We also thank C. Mayer for his editorial assistance and valuable suggestions. T.K. received financial support from grants from the Ministry of Ed- ucation, Science and Culture, Japan (nos. 06454003, 08041162, 11691196 and 11833018), the Fujiwara Natural History Foun- dation, and the Research Institute of Marine Invertebrates. Page 32 LITERATURE CITED BANDEL, K. 1998. Scissurellidae als Model fiir die Variations- breite einer natiirlichen Einheit der Schlitzbandschnecken (Mollusca, Archaeogastropoda). Mitteilungen aus dem Geo- logisch-Palaontologischen Institut der Universitat Hamburg 81:1-120. Di Geronimo, I., R. LA PERNA, A. Rosso & R. SANFILIPPO. 1993. Popolamento e tanatocenosi bentonica della Grotta dell’ Accademia (Ustica, Mar Tirreno Meridionale). I] Na- turalista Siciliano, 4 seiries 17:45—63. Dt GERONIMO, I., L. ALLEGRI, S. IMpROTA, R. LA PERNA, A. Rosso & R. SANFILIPPO. 1997. Spatial and temporal aspects of ben- thic thanatocoenses in a Mediterranean infralittoral cave. Rivista italiana di paleontologia e stratigrafia 103:15—28. FINLAY, H. J. 1927. Additions to the Recent molluscan fauna of New Zealand. No. 2. Transactions and Proceedings of the New Zealand Institute 57:485—487. Hayaml, I. & T. KAsE. 1992. A new cryptic species of Pycno- donte from Ryukyu Islands: a living fossil oyster. Transac- tions and Proceedings of the Palaeontological Society of Ja- pan, new series 165:1070—1089. HayamI, I. & T. KAse. 1993. Submarine cave Bivalvia from the Ryukyu Islands: systematics and evolutionary significance. The University Museum, The University of Tokyo, Bulletin 35:1-133. Hayaml, I. & T. KASE. 1996. Characteristics of submarine cave bivalves in the northwestern Pacific. American Malacologi- cal Bulletin 12:59-65. KANo, Y. & T. KASE. 2000. Taxonomic revision of Pisulina (Gas- tropoda: Neritopsina) from submarine caves in the tropical Indo-Pacific. Paleontological Research 4:107—129. KAsE, T. 1998a. The family Pickworthiidae (Gastropoda: Caen- The Veliger, Vol. 45, No. 1 ogastropoda) from tropical Pacific submarine caves: four new species of Sansonia. Venus, Japanese Journal of Mal- acology 57:161—-172. Kase, T. 1998b. The family Pickworthiidae (Gastropoda: Caen- ogastropoda) from tropical Pacific submarine caves: Seven new species of Microliotia. Venus, Japanese Journal of Mal- acology 57:173—190. Kase, T. 1998c. The family Pickworthiidae (Gastropoda: Caen- ogastropoda) from tropical Pacific submarine caves: five new species of Reynellona. Venus, Japanese Journal of Mal- acology 57:245—257. Kase, T. 1999. The family Pickworthiidae (Gastropoda: Caeno- gastropoda) from tropical Pacific submarine caves: Ampul- losansonia n. gen. and Tinianella n. gen. Venus, Japanese Journal of Malacology 58:91—100. Kase, T. & I. HAyAmI. 1992. Unique submarine cave mollusc fauna: composition, origin and adaptation. Journal of Mol- luscan Studies 58:446—449. Kase, T. & Y. KANo. 1999. Bizzare gastropod Pluviostilla pa- lauensis gen. et sp. nov. from a submarine cave in Palau (Micronesia), possibly with neritopsine affinity. Venus, Jap- anese Journal of Malacology 58:1-8. LA PERNA, R. 1998. A new Mediterranean Skeneoides (Gastro- poda, Skeneidae) from a shallow-water cave. Journal of Conchology 36:21—27. Lozougt, P. 1998. Mouvelles espéces de gastéropodes (Mollusca: Gastropoda) de l’Oligocene et du Miocéne intrérieur de l’ Aquitaine (sud-ouest de la France). Cossmanniana 5:61— 102. MarSHALL, B. A. 1993. The systematic position of Larochea Finlay, 1927, and introduction of a new genus and two new species (Gastropoda: Scissurellidae). Journal of Molluscan Studies 59:285—294. RHE BLIGER © CMS, Inc., 2002 The Veliger 45(1):33—44 (January 2, 2002) Reproductive Cycle of the Bivalves Ensis macha (Molina, 1782) (Solenidae), Tagelus dombeii (Lamarck, 1818) (Solecurtidae), and Mulinia edulis (King, 1831) (Mactridae) in Southern Chile MARIA H. AVELLANAL', EDUARDO JARAMILLO!, ELENA CLASING?, PEDRO QUIJON! anp HERALDO CONTRERAS! ' Instituto de Zoologia > Instituto de Biologia Marina, Universidad Austral de Chile, Valdivia, Chile Abstract. The reproductive cycles of the bivalves Ensis macha (Molina, 1782), Tagelus dombeii (Lamarck, 1818), and Mulinia edulis (King, 1831) were studied at six sites in southern Chile (38—43°S) from November 1996 to December 1997. Samples of E. macha came from three subtidal shallow depths; those of 7. dombeii from two subtidal depths and one intertidal site; and samples of M. edulis originated in one subtidal shallow depth and one intertidal site. Thirty specimens were collected monthly for standard histological analyses. Water samples were also collected to determine salinity, temperature, and chlorophyll a content. In general, the reproductive cycles of the three species were characterized by long spawning periods, beginning during late spring-summer. In some cases, that period extended during autumn- winter until the following spring. The gonads of most of the populations showed quite short recovery periods, with the exception of populations located farther south, which needed more time to begin a new cycle. Comparison of subtidal versus intertidal populations showed that the gonad stages developed more slowly for the latter populations. The earlier results show that variability exists in the timing of gametogenic cycles of E. macha, T. dombeii, and M. edulis along the coast of southern Chile. No significant relationship was found between seasonal variability of reproductive stages and seasonal variability of water characteristics. Among these characteristics, water temperature and chlorophyll a content were the most important. Potential fecundity varied geographically in E. macha and T. dombeii, whereas, in general, no variability was observed in mean sizes of oocytes of the three species. These results must be taken into account when management plans are designed; thus, the timing of the gametogenic cycles of bivalves of economic importance must be studied along their full geographic ranges. INTRODUCTION Knowledge of the reproductive cycles of marine inver- tebrates of economic importance is basic to culture activ- ities and management of natural stocks. In that way, it is possible to regulate fishery activities and set up closing seasons to preserve the species, via the protection of re- productive individuals (e.g., Defeo 1987, 1989, 1993). The reproductive cycles of different bivalve species are unique for each population, varying according to geo- graphic location (Sastry, 1979). The high seasonality of the environment in medium to high latitude locations re- sults in annual cycles, with gametogenesis during winter, and spawning during the spring-summer season. In con- trast, the reproductive cycle in low latitude locations is has been particularly studied in species of economic 1m- portance (Tarifeno, 1980; Manzi et al., 1985; Heffernan et al., 1989a, b; Laasuy & Simons, 1989; Kanti et al., 1993; Urban & Campos, 1994; Villalejo-Fuerte et al., 1996a; Gallardo & Weber, 1996). Apart from the variability in reproductive cycles relat- ed to geographic variation, it has been shown that zona- tion across shore also influences some of the character- istics of the reproductive cycles such as the production of somatic and sexual tissue and differences in fecundity and size of oocytes (McLachlan, 1974; Griffiths, 1981; Harvey & Vincent, 1989, 1991; Richardson, 1993; Walk- er & Heffernan, 1994; Brousseau, 1995). For example, Borrero (1987) found three important differences between characterized by long or continuous spawning periods (Heffernan & Walker, 1989; Heffernan et al., 1989a, b). Environmental factors such as water temperature and sa- linity, photoperiod, and food resource availability have been mentioned as concrete causes for that latitudinal var- iability (Giese & Pierse, 1977; Mackie, 1984). The lati- tudinal variability in the reproductive cycle of bivalves subtidal and intertidal populations of the mytilid Geuken- sia demissa (Dillwyn) in South Carolina, USA: time of the onset of gametogenesis, time of occurrence of spawn- ing, and length of time remaining in a mature reproduc- tive condition before spawning. That was probably due to changing conditions in submergence throughout the tidal cycle, which result in changing environmental tem- Page 34 30°S 40°S 50° S The Veliger, Vol. 45, No. 1 76° W 74° W 72° W 70° W Figure 1. Location of sampling sites at the coast of south central Chile. peratures and time for feeding, conditions that may influ- ence the reproductive output of invertebrates (Barber & Blake, 1981; Bayne & Newell, 1983). The coast of southern Chile (38—43°S) is characterized by small bays and numerous microtidal estuaries. Some of the most common bivalves are Ensis macha (Molina, 1782) (Solenidae); Tagelus dombeii (Lamarck, 1818) (So- lecurtidae); and Mulinia edulis (King, 1831) (Mactridae). Ensis macha, Tagelus dombeii, and Mulinia edulis occur along a wide latitudinal range of the Chilean coast, the first species from Caldera (approx. 27°S) to Magallanes (55°S), and the latter two species throughout all the Chi- lean coast (Osorio et al., 1979). They are among the most common bivalves subjected to commercial fisheries along the coast of southern Chile (approx. 38—43°S). Approxi- mate commercial sizes are 100-180 mm for E. macha, 70—90 mm for T. dombeii, and 50-70 mm for M. edulis. Landing fisheries along the Chilean coast started in 1988 for E. macha, 1965 for T. dombeii, and 1994 for M. ed- ulis. In recent years, landing figures for E. macha, T. dom- beii, and M. edulis in southern Chile (about 38—43°S, Ar- auco to Quellon, Figure 1) represented an average of 99.7, 99.5, and 80.7% of the total national landing figures (data from 1988-1997 for E. macha and T. dombeii, and from 1994 to 1997 for M. edulis). During the period 1988-1997, the highest landing figures from E. macha and 7. dombeii were 8595 (1991) and 7260 annual tons (1988), respectively. From 1994-1997, the maximum landing for M. edulis reached 2553 annual tons (1994). The vast majority (approx. 90%) of landings are used in the canning industry (Sernapesca, 1998). Despite the economic importance of these three spe- cies, there are few studies which deal with the effect of geographic variability on their reproductive biology. San- tos-Salas et al. (1998) and Aracena et al. (1998) described growth and feeding of juveniles and the reproductive cy- cle of E. macha in shallow waters of Golfo de Arauco (approx. 38°S). For M. edulis there is only one study on the external morphology of larvae (Fuentes, 1988), and another study on production of spats (Paredes & Hernan- dez, 1986). For 7. dombeii there are several studies on its reproductive cycle at several localities on the Chilean coast, showing variations in its reproductive cycle (Lasen, 1979; Fierro, 1981; Arratia, 1998). Because of the variability of coastal waters along the Chilean coast (Brattstrom & Johanssen, 1983; Strub et al., 1998; Viviani, 1979), it is reasonable to expect some var- iability in reproductive cycles along the latitudinal ranges of these species. The purpose of the present study was to analyze the reproductive biology of E. macha, T. dombeii, and M. edulis, (Figure 2) at different areas of a coastal M. H. Avellanal et al., 2002 Page 35 range spanning approximately 600 km of the southern Chilean coast. Because E. macha lives primarily under water, we obtained only subtidal samples for this species. For T. dombeii and M. edulis, however, we obtained in- tertidal and subtidal samples. Thus, for 7. dombeii and M. edulis we were able to analyze populations living at different latitudes and depths. MATERIALS ann METHODS Study Area Samples were collected from six sites on the coast of southern Chile (Figure 1). Subtidal samples of E. macha were collected from Tubul, Golfo de Arauco (37°14'S, 73°29'W), Bahia de Corral (Corral hereafter) (39°50’S, 73°28'W), and Bahia de Ancud (Ancud_ hereafter) (41°50’S, 73°47'W). Subtidal samples of 7. dombeii came from Tubul and Corral; intertidal samples of this species were collected from Coihuin, Golfo del Reloncavir (41°28'S, 72°41'W). Subtidal samples of M. edulis were collected at Maullin (41°39'S, 73°37'W); intertidal sam- ples of this species came from Yaldad (43°07'S, 73°44'W) (Figure 1). Sampling and Treatment of Samples Samples were collected from November 1996 to De- cember 1997. Subtidal samples were collected by semi- autonomous diving from shallow water beds (7-14 m depth). Intertidal samples were collected during spring low tides. Due to rough sea conditions, no samples were collected during April in Corral and during May at Tubul and Corral. For histological analysis of the gonads, samples of 30 specimens were collected from each one of the study sites. The bivalves were kept at low temperature (3°C) to be processed within 24 hours after collection. After dis- section, the gonads were fixed in aqueous Bouin’s fixa- tive. After embedding in paraffin, 7 tm serial sections were cut and stained with hematoxylin and eosin (Ban- croft & Stevens, 1977). Ten sections of the gonad of each specimen were examined under the light microscope to determine the gonadal organization and the seasonal ga- metogenic cycle. The following categories of gonad de- velopment were used in this study (cf. Peredo et al., 1987; Brousseau, 1995). Early Active. Phase of gamete proliferation and devel- opment. Gonadal follicles are small and have thick walls; the interstitial tissue is abundant and disseminated among the gonadal follicles. In males, spermatogonia are close to the follicular walls, while few spermatids and sper- matocytes are located near the center of the follicles. In females, oogonia can be seen embedded in the follicular walls; pre-vitelogenic oocytes and vitelogenic oocytes with cytoplasm extend into the lumen of the follicles. Late Active. This is the phase of gamete maturation. In both sexes a reduction of gonias and an increase in the mature gametes (oocytes and spermatozoa) can be seen. In males the sperm form radially oriented columns with their tails toward the center of the follicles. In the female gonad, vitellogenic oocytes are more numerous, and some mature oocytes are free in the lumen of the follicles. Ripe. Gonadal follicles are expanded in these stage with their walls being very thin and with a lower number of early stage cells. In males, mature sperm form dense masses and cells. In females, the follicles are crowded together and filled with mature oocytes. Partially Spawned. In both sexes the follicles still con- tain gametes, but these are less numerous than in the ripe stage. It is still possible to see gametes in early stage (spermatids and vitellogenic oocytes attached to the wall). Spent. In both sexes, most of the follicles are devoid of gametes with some residual mature spermatozoa or oocytes. Recovery. Most of the follicles are devoid of gametes, although some follicles have a few residual gametes. The interstitial tissue has increased and surrounded the folli- cles. The stereometric technique of Weibel (1969) was used for fecundity determination, i.e., the volume of different cellular components was determinated from the gonad analyses, through the relationship between the surface of that component and the total surface (Neuer, 1966). The diameter of 100 oocytes (from different females) was measured, using an eyepiece graticule calibrated with a stage micrometer. Measurements were made along the longest and the shortest axis of the oocytes. From these data, mean oocyte size and standard deviation were ob- tained. Maturity of the oocytes was determined according to Peredo et al. (1987) and Masello (1987), i.e., free oo- cyte in the light of the follicle with cytoplasm of the lumpy aspect and acidophile; large rounded nucleus; clearer color than cytoplasm with a very clear nuclear membrane and granulated chromatin; large nucleoli in the interior to which small ones can be added. Water samples from the subtidal sampling sites (Tubul, Corral, Maullin, and Ancud) were collected from about 50 cm above the bottom to determine temperature, salin- ity, and chlorophyll a content. At Coihuin and Yaldad (intertidal sites) water samples were collected during ris- ing tides (about 50 cm depth). Temperatures were mea- sured in situ with a mercury thermometer (+0.1°C). Sa- linity was measured with a portable salinometer Hydro- bios. The chlorophyll a content was measured after the filtration of 2 liters of water in Milipore filters with 0.45 zm of opening. The filters were kept at low temperatures (—7°C) and in darkness. After a short period (5—7 days), they were kept in 90% acetone for 24 hours to extract pigments, and centrifuged at 3500 rpm for 15 min. The absorbance of the supernatant was measured at 750 and 665 nm (Strickland & Parsons, 1972). One-way analysis of variance (Sokal & Rohlf, 1995) Page 36 Ens/s tnacha The Veliger, Vol. 45, No. 1 Tagelus dombe/i Figure 2. External and internal views of shells of Ensis macha, Tagelus dombeii, and Mulinia edulis. was used to compare the mean potential fecundity among bivalves of the same species collected at different sites. If the analysis of variance indicated significant differenc- es among means (P < 0.05), these were compared using the a posteriori Tukey’s multiple comparison test (Day & Quinn, 1989). Due to the fact that mean oocyte diameter did not have a normal distribution, a non-parametric anal- ysis (Kruskall-Wallis ANOVA) was used. Simple regres- sion analysis (Sokal & Rohlf, 1995) was carried out to evaluate relationships between percentages of mature (ripe stage) and spawned (partially spawned and spent stage) and variability of water temperature and chloro- phyll a water content. RESULTS Water Characteristics Figure 3 shows the temporal variability in temperature, salinity, and chlorophyll a content of water at each study site. Water temperature showed small variability at Tubul: from 12°C in March to 14.5°C in April and July. More seasonal variability was found farther south; from a min- imum of 11, 10, 10, 12 and 10°C during winter time to a maximum of 13.6, 16, 18.5, 16, and 15°C during late spring-summer at the waters of Corral, Maullin, Coihuin, Ancud, and Yaldad, respectively (Figure 3). Water salin- ity varied little at the shallow waters of the bays of Tubul, 20 40 16 % zoe) \ 12 ane a 20 8 10 20 40 16 EX) LOO . 12d Ty Oak 20 Be 8 10 S 20 - 40 ee 16 ‘ E 30 C2 \ a 20 =) — 5 8 Se iO = 20 = 40 = 16 = 30 o 12 ” 20 = 10 aga 20 40 36 a La SO Ta eee ee 24 12 20 12 8 10 O NDJFMAMJ JASOND Page 37 36 maa Aa Ne 36 24 12 Corral Oo —@ Ps. * * fv 24 : ’ rs Coihuin (e) be * Maullin chlorophyll a(ugl ) is) o Ancud 20 40 36 16 30 24 12 20 12 Yaldad 8 10 0 ND JFMAMJJASOND ND JFMAMJJASOND gel 97 96 97 96| 97 months Figure 3. Temporal variability of temperature, salinity, and chlorophyll a content in the waters of the sampling sites. * = no data Corral, and Ancud (from about 28-34 ppm). More vari- ability was found at the shallow waters of Maullin (10— 33 ppm), and at the intertidal sites of Coihuin and Yaldad (15-34 ppm). In general, the highest content of chloro- phyll a at all study sites was found during summer (De- cember—February) and spring months (September—No- vember), whereas the lowest occurred during late fall and winter. During late summer of 1997 (March), the intertid- al waters of Yaldad registered the highest chlorophyll a value found in this study (31.2 wg/l) (Figure 3). Morphology of Gonads Microscopic analyses revealed that E. macha, T. dom- beii, and M. edulis are dioecius species without external sexual dimorphism. While no color differences exist in the gonads of E. macha and T. dombeii, the gonads of M. edulis vary in color, being dark royal purple in fe- males, and orange in males. The gonad structure is similar in the three species; it is embedded in the visceral mass together with the hepatopancreas and gut. It does not have any kind of enveloping sheet; in some regions it is dis- sected by muscular strings originating in the body wall. Gametogenic Cycles Ensis macha. Figure 4 shows the frequency of the dif- ferent gonad stages of E. macha at the shallow waters of Tubul, Corral, and Ancud. At the beginning of the study (November—December 1996), the three populations were in late active and ripe stages. During January, 23% and 13% of the individuals collected at Corral and Ancud had partially spawned. Twenty-seven percent of the animals collected during February in Tubul had reached this stage. During late summer (March), 100%, 93%, and 50% of the populations of Tubul, Corral, and Ancud, respectively, were partially spawned. One hundred percent of the ani- mals of Tubul and Ancud were in this stage during April. During the winter and spring months, the three popula- tions showed significant differences in their gametogenic cycles. During June and July, about 55% of the specimens of E. macha in Tubul had their gonads in early and late active stages. From June to August, percentages of ripe individuals varied (approx. 20-50%). During August, partially spawned individuals were collected again (approx. 40%); this last stage persisted during the rest of the spring (September—December). During June—August, WUMMMMMUM“, MME ZX@: EEA Tubul WUMUMMMMMMXMEqM VV WUCMMHH@@@@_"|M||#]Z!/||M|//#X]X.]! MMtttttt#a WML ZZ SS = b> no oO 2 o WM Corral WMMMHMHHHMMMVV0 1100 WUE LL WU LEELA ULM frequency in percentage LXZ/ZZ ELLY, NDJFMAMJJASOND lf, y WWMM, WWMM“ Ancud WUMMMMH#X@_|MJ!VZ@ZT| M#Y]_W M/J]EMMbtb Ltt % WUMMMMHH@THTTTT/HH MMM Mtb ‘ZY WHMMHHXH_ H/!VHTFHVT@YMM0@0010 4 late active partially spawned [J early active MB ripe [_]spent Figure 4. Seasonal variability in the frequencies (percentages) of the different stages of the gametogenic cycle of the gonad of Ensis macha at the shallow subtidal of Tubul, Corral, and Ancud. * = no data the population of Corral was represented by ripe and spawned animals in similar proportions. From September to November, 100% of the animals were in partially spawned stage. The specimens collected during May in Ancud were ripe and partially spawned; during June—July, 100% of them were in this last stage. From August to November, individuals were either recovering (late active The Veliger, Vol. 45, No. 1 stage) or mature (ripe stage). During December, 100% of the animals collected in Ancud were mature. Tagelus dombeii. Figure 5 shows the sequence of the reproductive cycle of T. dombeii at the shallow waters of Tubul and Corral and at the intertidal of Coihuin. During the first 2 months of the study (November and December 1996), the three populations were in different reproduc- tive stages. Whereas the animals of Tubul were in late active or ripe stage, those of Corral and Coihuin were ripe or spawned (primarily at Corral, 97% during Decem- ber). During January, the individuals of Tubul had yet not spawned, whereas most of the individuals from Corral and Coihuin were spawning, with some specimens also in the ripe stage (5% and 20%, respectively). The begin- ning of a new cycle (individuals in early active stage) was observed in June for the individuals of Tubul and Coihuin, and in July for the specimens of Corral. During late winter (August-September), the population of Tubul was spawning, even when ripe animals were also col- lected. At the same time, the populations of Corral and Coihuin were still in early and late active stages. During the spring (October-December), most of the specimens collected at Tubul were spawning. All the individuals col- lected at Corral were in late active stage during October, and ripe during November. In Coihuin, most of the in- dividuals (approx. 95%) were ripe in October; and in No- vember, half of the population was partially spawned. Mulinia edulis. The reproductive cycle of M. edulis at the shallow waters of Maullin and at the intertidal of Yal- dad is shown in Figure 6. During November 1996, dif- ferent reproductive stages were found (early active, late active, and ripe stage) at both sites. During summer (De- cember—March), both populations were in ripe and par- tially spawned stages, with the highest percentage of spawned individuals found at the end of the summer (approx. 50% in Maullin and 77% in Yaldad). Both pop- ulations were in similar stages during April to June. Spec- imens collected at Maullin during July were in recovery, ripe, and spawn stages, quite a similar situation (but with- out recovery stages) to that observed for the intertidal population of Coihuin. During August, both populations were in similar stages of the gametogenic cycle. From September to November, the specimens of Maullin were spawning, while those of Yaldad had begun a new cycle (early and late active stages), an assertion supported by the dominance of ripe stages during November. Gametogenic Cycles and Water Characteristics Table | shows the results of regression analyses carried out between the seasonal variability in the percentages of mature (ripe stages) and spawned individuals (partially spent and spawned) and the temporal variability of water characteristics. The temporal variability in the percentage of mature females of E. macha at Tubul was positively correlated with that of chlorophyll a content. The tem- M. H. Avellanal et al., 2002 Tagelus dombei/ 100 EneeE i on NN NUNN ae VA NNN AR TR \N NANNA VA NNN oe VN NNNNN \\ NNN a NA Wh vy WwW VA VNR NN NNNAN Py VN Wh NN NN \N NNNN 0 NN NAAR D @ ep) 100 un = ie NN ® NA | = NVWN 3 NNN es NNNAN NN NN Cc = VIV\\ orra z NN N\A NVNN rs) NVNN 2 TWh NNN NAN 2 MA ye TWN NA VN NN n N \ NNN Ww \N Coihuin N N 1 KS MMMMMM#@Z_T_@(M@@@_t NDJFMAMJJASOND 96 | 97 FJearly active late active BBripe KY partially spawned CL) spent recovery Figure 5. Seasonal variability in the frequencies (percentages) of the different stages of the gametogenic cycle of the gonad of Tagelus dombeii at the shallow subtidal of Tubul and Corral and the intertidal site of Coihuin. * = no data poral variability in the percentages of spawned specimens (either the whole population or males and females by themselves) was also correlated with the chlorophyll a content, but inversely. Only the females of E. macha showed a significant relationship to the water character- istics at Corral; mature females were more abundant when chlorophyll a was higher, whereas spawned females peaked when chlorophyll a was lower. The results found from E. macha at Ancud showed that mature individuals were more abundant when temperatures were higher, Page 39 Mulinia edulis NEN YN NN NBN \ TR NN VN N 5 1 i tT Maullin wi DBNBS N BRN CNN \ WANN N NANAK ig > ” (o) frequency in percentage Yaldad WMV WUMMMM@@Z]Z=]_ |blttota WUMMMMZZZ]Z: TJ IIZ=™”: WUMMMHH@=@"/"'||//|']U00tt WUMMMM@Z]Z?Z?7™#|'||’'!'6#bttt LMMA____| M J 97 f=] early active late active Wi ripe partially spawned () spent & recovery Figure 6. Seasonal variability in the frequencies (percentages) of the different stages of the gametogenic cycle of the gonad of Mulina edulis at the shallow subtidal of Maullin and the intertidal site of Yaldad. * = no data whereas spawned females peaked when temperatures were lower. At the intertidal site of Coihuin, a significant correlation was found between the temporal variability of the reproductive stages of 7. dombeii and physical fac- tors; thus, percentages of total individual spent, mature females and spawned individuals were more abundant when water temperatures were higher. Similarly, percent- age of mature females of M. edulis at the intertidal site of Yaldad peaked when water temperatures were higher (Table 1). Diameter of Oocytes and Potential Fecundity The mean diameter of oocytes was 50-51 wm for E. macha, 38-39 ym for T. dombeii, and 41—42 wm for M. edulis, without significant differences between sites (P > 0.05, Table 2). Mean potential fecundities were higher for E. macha, particularly in Tubul and Corral where those fecundities (approx. 18—19 X 10° oocytes per individual) were significantly higher (p < 0.05) than that estimated for the population sampled at Ancud (Table 2). The high- Page 40 The Veliger, Vol. 45, No. 1 Table 1 Results of the regression analyses carried out between the percentages of mature and spawned animals and the temporal variability of water temperature and chlorophyll a content at the study sites. Results are only given for those analyses which rendered significant correlations. Species Study site Ensis macha Tubul Corral Ancud Tagelus dombeii Coihuin Mulinia edulis Yaldad % mature females = % spawned males and females % spawned females % spawned males % mature females % spawned females % mature males and females % mature females % spawned females % population spent % mature females % spawned females % spawned males Regression equation ie p —5.74 + 6.55 chlor a 0.88 0.00 = 83.28 — 5.65 chlor a —0.58 0.04 = 86.59 — 6.06 chlor a —0.59 0.04 = 724.96 — 49.79 chlor a —0.81 0.00 = 10.79 + 14.44 chlor a 0.69 0.02 = 89.27 — 16.04 chlor a —0.71 0.01 = OWA a le eo ila G 0.61 0.03 = —220.67 + 18.88°C 0.59 0.03 = 313.46 — 19.91°C —0.58 0.04 = —55.45 + 6.67°C 0.62 0.02 = —66.78 + 7.20°C 0.68 0.01 = —62.53 + 6.66°C 0.68 0.01 = —74.78 + 8.2°C 0.67 0.01 = —103.68 + 10.12°C 0.57 0.04 % mature females est mean potential fecundity for 7. dambeii was estimated for the subtidal population sampled at Tubul. That fecun- dity (approx. 11 x 10° oocytes per individual) was sig- nificantly higher than that estimated for the subtidal pop- ulation of Corral (8 < 10° oocytes per individual) and the intertidal samples of Coihuin (approx. 6 X 10° oocytes per individual), the last ones without significant differ- ences between them (Table 2). The estimated mean po- tential fecundities estimated for the subtidal and intertidal populations of M. edulis (Maullin versus Yaldad) ranged from approx. 10-14 x 10° oocytes per individual without significant differences between them (Table 2). DISCUSSION The results of this study show that in the study area E. macha, T. dombeii, and M. edulis have an annual cycle of reproduction with periods of extensive spawns begin- ning during late spring-summer (November 1996 to Feb- ruary 1997). That period extends until autumn, and in some cases continues without stopping until next spring as was observed clearly in the intertidal population of M. edulis in Yaldad. In general, the recovery periods of the gonads are quite short and extend for more than 2 months just in the populations of 7. dombeii in Corral and Coi- huin, being the population studied of this species at the last place with the clearest annual cycle (i.e., all the gonad stages well represented). The reproductive cycle of E. macha in Tubul and Cor- ral was rather similar, with a quick recovery of the gonad during winter, after which spawning extended until the end of the study. The population of Ancud showed a more marked annual cycle with a new maturation period during the spring continuing toward the summer; spawning be- gan during early summer (January 1997). The reproductive cycle of 7. dombeii of Tubul differed from that of Corral and Coihuin. The individuals collect- ed from the first site began a new cycle during winter (June—July) which resulted in ripe individuals and spawn- ing throughout spring. On the other hand, the beginning of a new cycle for the populations of Corral and Coihuin spanned a longer period of time; consequently, no spawn- ing was found for Corral at the end of this study, whereas about 50% of the individuals of Coihuin were in this stage for that time. Thus, the gonads of the populations of 7. dombeii located farther south take a longer time to go through all the stages before spawning. The gametogenic cycle of M. edulis also showed in- tersite variability. While the subtidal population showed a continuous spawning and no beginning of a new cycle during the study period, the intertidal populations (also spawning almost all year round) showed the beginning of a new reproductive cycle during early spring. The earlier results show a variability in the gameto- genic cycles of E. macha, T. dombeii, and M. edulis along the geographic range studied. Sastry (1979) considered water temperature as one of the most important factors in the regulation of the differ- ent stages of the reproductive cycle in marine inverte- brates. Indeed, temperature is one of the main causes of differences in the timing of gametogenesis and spawning of different populations of the same species (Ropes, 1968: Tarifeno, 1980; Manzi et al., 1985; Urban & Campos, 1994; Garcia-Dominguez et al., 1996). Vilalejo-Fuerte et al. (1996a) showed that in Baja California, Mexico, the increase in temperature inhibits gametogenesis in the cockle Laevicardium elatum (Sowerby). In other species of bivalves located in the Gulf of California, the spawn- ing period is directly related to decrease of water tem- M. H. Avellanal et al., 2002 Table 2 Mean size of oocytes and mean potential fecundity (with standard deviations in parentheses) for each species at the study sites. A summary of the statistical analyses (F and p; see Material and Methods) is also given. The same capital letters indicate no significant differences in the fecundity comparisons; different letters for the opposite results (1.e., significant differences). Mean potential fecundity ANOVA K-W ANOVA (millions of oocytes Mean size of per individual) oocytes (4m) Study site Species << 0.00 43 (1,573,002) 2 18,267,243 (4,369,424) 2 0.41 19,61 1.79 = Tubul Corrs Ensis macha mMimnnctc S b S i) S S ee) i=») a é~ = (oa) PTREAAS Keoertraa Sah ON hog Is wotons owonwytrn NY CUS SD AMAOMARWMNM CN Sep () Nope Qe eo CoS) TREE QUOUES IG: ONO OND mar rN SOM ISOS Y~ooNnTtSO ™~ - i A) i=) j=) — fon] be) + So S Beh Ba eee LANES AIS OoOrrnwatm VyewevVevVewTrw Ancu Tubul Corral Coihuin Maullin Yaldad Tagelus dombeii Mulinia edulis Page 41 perature (Villalejo-Fuerte et al., 1995). There are, how- ever, other species in which the water temperature does not influence gametogenic cycles (Garcia-Dominguez et al., 1996). In this study, we found that water temperature affected in some way the timing of the gametogenic cycle of E. macha in Ancud, T. dombeii in Coihuin, and M. edulis in Yaldad. Ancud was the southern study site for E. ma- cha, while Coihuin and Yaldad were the intertidal sites. It is indeed possible that at those places, a wider temper- ature variability occurred than that measured here, which may explain the above-mentioned relationship between timing of reproduction and water temperature. Food resources are also important, and the percentage of individuals in different gonad stages is related to food amount and availability, primarily during the final period of maturation of the gametes (late active and ripe stages) and during the period of spawning (Sastry, 1979; Bayne & Newell, 1983; MacDonald & Thompson, 1985; Vila- lejo-Fuerte et al., 1996a). In this way, the females have enough energy to carry out the vitelogenic process, and later, larvae also have enough food for subsistence. The direct and significant relationship between the percentage of mature females of E. macha and T. dombeii and the concentration of chlorophyll a in the localities of Tubul and Corral suggest that food is the main cause of final maturation of the oocytes. The other populations could obtain that energy from that accumulated in their body or from another food type different to the phytoplankton (e.g., dissolved organic matter). For an intertidal popu- lation of Semele solida (Gray) in Coihuin, Arratia (1998) determined a continuous reproductive cycle, with libera- tion of gametes during the 15 months of the study, even during periods of low food concentration. Similar results were found by Jaramillo & Navarro (1995) for the mytilid Aulacomya ater in Yaldad. It has been demonstrated or suggested for bivalves that the transfer of nutrients exists from the somatic tissue toward the gonad during game- togenesis (Sastry & Venn, 1979; Barber & Blake, 1981; Vilalejo-Fuerte et al., 1996b). Le Pennec et al. (1991) demonstrated for the pectinid Pecten maximus L. that oth- er pathways exist for energy incorporation to the devel- opment of gametes, i.e., the recycling of atresic material and direct transfer of metabolites from the intestinal loop to the developing gametes. Sastry (1979) also mentioned the importance of dissolved organic matter, bacteria, and organic aggregates as a food source for bivalves, apart from the usual phytoplankton. Clasing et al. (1998) found at the intertidal flats of Coihuin that Semele solida spawns during autumn-winter when concentrations of phyto- plankton are low. These authors stated that because Sem- ele solida is able to use the organic matter deposited on the surface sediments that organic matter would be an alternate energy source during autumn and winter. A sim- ilar explanation has been also given for the continuous Page 42 reproductive cycle of the intertidal bivalve Diplodonta inconspicua at the same site (Clasing et al. 1998). The comparison between gametogenic cycles of sub- tidal versus intertidal populations shows that intertidal populations exhibit a slower development of the different stages of the reproductive cycle. Landers (1954) suggest- ed that intertidal individuals of Mercenaria mercenaria living in the east coast of USA spawn earlier than subtidal individuals. Borrero (1987) also found that the beginning of gametogenesis and spawning in Geukensia demissa (Dillwyn) occurs earlier in low intertidal populations than high intertidal populations. Walker & Heffernan (1994) showed that the reproductive pattern of populations of Mercenaria mercenaria of Georgia (USA) is affected by the emersion time. On the other hand, Eversole et al. (1980) did not find differences in the reproductive param- eters of subtidal and intertidal populations of the same species in the coast of South Carolina. Brousseau (1995) compared the results obtained for intertidal populations of Crassotrea virginica (Gemlin) in Long Island (USA) with those obtained before by Loosanoff (1942) 40 years earlier for subtidal populations, and concluded that not much difference exists as far as timing of the reproductive cycle is concerned. The comparison of potential fecundity showed that the values estimated for E. macha were higher than those for T. dombeii and M. edulis. These differences may well be related to volume differences in gonadal tissue among species, a parameter directly correlated to the body size of individuals, 1.e., the larger E. macha probably has larg- er gonads. Although no estimation of volume of gonads was carried out in this study, the body length of E. macha is longer than that of the other two species (see Figure 2). The potential fecundity of E. macha and M. edulis studied here is similar to other species of Chilean bivalves with plantotrophic larvae such as Aulacomya ater (Mo- lina), Choromytilus chorus (Molina), Venus antiqua (King & Broderip), Eurhomalea rufa (Lamarck), Meso- desma donacium (Lamarck), and Prothothaca thaca (Mo- lina) (Lozada, 1989). The results of this study showed that for E. macha and T. dombeii the potential fecundity was lower farther south. Differences in body size among sites may also be invoked to explain that result, i.e., the larger females collected farther north (Jaramillo et al., 1998, unpublished data) had larger gonads and thus, more potential fecundity. However, the eventual effect of body size on size of gonads and potential fecundity seems to not affect mean sizes of oocytes. As a matter of fact, our results did not show any consistency. Thus, subtidal and intertidal pop- ulations of 7. dombeii and M. edulis did not show sig- nificant differences in mean sizes of oocytes. This is dif- ferent to the findings of other authors, such as Walker & Heffereman (1994) who found in England that subtidal populations of Mercenaria mercenaria have larger go- nads and more oocytes than specimens living higher up The Veliger, Vol. 45, No. 1 the coast. Also, Harvey & Vincent (1989, 1991) found that differences in exposure time to air during low tide is coincident with differences in potential fecundity of Ma- coma balthica inhabiting tidal flats of the Saint Lawrence Estuary (Canada). No studies dealing with diameter of oocytes exists for E. macha and M. edulis. The mean diameter determined in this study for 7. dombeii is smaller than that mentioned for other populations of the same species (Lozada, 1989). Interannual variability in mean size of ooctyes may exist, as has been shown for Macoma balthica (L.) in Canada (Harvey et al., 1993) and Mercenaria mercenaria (L.) in South Carolina (USA) (Manzi et al., 1985) In conclusion, there is variability in the timing of the gametogenic cycle of E. macha, T. dombeii, and M. edulis studied along the coast of southern Chile, i.e., the length of spawning and ripe stage periods varied. This is a key issue as far as management issues are concerned. Any management plan must take into account the geographic variability in the gametogenic cycles described here when closing seasons and minimum size of harvesting are de- termined. Due to the economic importance of many bi- valves along the Chilean coast, there is an urgent need to evaluate the timing of gametogenic cycles of these spe- cies along their full geographic ranges. Acknowledgments. We thank Ivan Céspedes (Instituto de Fom- ento Pesquero, Talcahuano), Sandro Araneda (Valdivia), David Patino (Universidad Austral de Chile, Maullin), Marco Lardies (Valdivia), and Nersio Saldivia (Instituto de Fomento Pesquero, Ancud) who collected the samples. This study was financed by Project FIP N° 96—46 ‘Estudio biol6gico pesquero de los recur- sos almeja, navajuela y huepo en las VIII y X Regiones.”” We are grateful to Orlando Garrido (Instituto de Embriologia, Univ- ersidad Austral de Chile) who assisted us with the stereometric technique. MHA was funded by Direccion de Investigacion y Desarrollo, Universidad Austral de Chile during the final data analyses and manuscript preparation. EJ acknowledges financial support from FONDAP O & BM (Programa Mayor N° 3) while preparing the manuscript. LITERATURE CITED ARACENA, O., L. MEDINA, A. CARMONA & I. LEPEZ. 1998. Ciclo reproductivo de Ensis macha (Molina, 1782) en base a in- dices gonadicos macrosc6pico y su validacion histoldgica. 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HEFFERNAN. 1994. Temporal and spatial effects of tidal exposure on the gametogenic cycle of the northern quahog, Mercenaria mercenaria (Linnaeus, 1758), in coastal Georgia. Journal of Shellfish Research 13:479—486. WEIBEL, B. 1969. Stereological principles for morphometry in Electron Microscopy Cytology. International Review of Cy- tology 26:235-302. The Veliger 45(1):45-54 (January 2, 2002) THE VELIGER © CMS, Inc., 2002 Sclerochronology and Growth of the Bivalve Mollusks Chione (Chionista) fluctifraga and C. (Chionista) cortezi in the Northern Gulf of California, Mexico BERND R. SCHONE, DAVID H. GOODWIN, KARL W. FLESSA, DAVID L. DETTMAN anp PETER D. ROOPNARINE! Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA; bschoene @ geo.arizona.edu Abstract. Sclerochronology and analysis of oxygen isotopes reveal the age, growth rate, and growth patterns of Chione (Chionista) cortezi and Chione (Chionista) fluctifraga. Chione (C.) cortezi grows more quickly than Chione (C.) fluctifraga, but has a shorter life span (8 years versus 16 years). Microgrowth increments form with tidal periodicity, and their width is mostly influenced by temperature. Microincrement patterns reveal that maximum growth occurs from April to June and again in October. Growth is reduced during the hottest part of the summer and the coldest part of the winter. Growth breaks often occur in December/January and August. Timing of shell growth and environmental condi- tions were verified by high-resolution oxygen isotope measurements. INTRODUCTION Bivalve mollusks of the genus Chione Megerle von Mihlfeld, 1811, inhabit many coastal areas around the world (Moore 1969:N686). Although they are often com- mercially exploited, little is known about their life span, overall growth patterns, and growth rates. The effect of temperature on the growth rate of Chione species is not well understood. Such information is important for the management of shellfish resources and mariculture. Early attempts to determine the age and growth rate of mollusks used shell-weight or size-frequency analysis. The disadvantages of these methods have been reviewed by Berta (1976) namely: (1) the exact age of the youngest year class remains unknown; (2) year classes can be ab- sent; and (3) size or weight ranges of specimens of dif- ferent year classes can overlap due to differences in en- vironmental conditions during their life. The major con- centric rings on the external shell surfaces of mollusks have often been interpreted as annual growth patterns. However, they cannot always be distinguished unequiv- ocally because rings may also be caused by non-seasonal disturbances. In addition, annual growth rings are crowd- ed at the ventral margin in older specimens and make counting and interpretation difficult (see Zolotarev, 1980). Other researchers (e.g., Jones et al., 1978; MacDonald & Thomas, 1980) suggested that the most reliable method is to count the annual growth increments (first order in- crements or “‘Ist-order layer’? sensu Barker, 1964) pre- served in radial cross-sections of the shells. -' Current address: Department of Invertebrate Zoology and Geology, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118-4599, USA. Since Wells’s (1963) pioneering study, in which the microgrowth increments (higher order increments) of cor- als were used to infer the number of days in a Devonian year, many articles have dealt with the microgrowth in- crements of bivalve mollusks and other animals (for a review see Rhoads & Lutz, 1980 and references therein). This type of study has been termed “‘sclerochronology” (Buddemeier, 1975; Hudson et al., 1976). Sclerochronology can be used to elucidate differences in growth rates and life histories of morphologically sim- ilar species. Sclerochronological methods can be applied to shells of fossil (Pannella 1976; Schone, 1999) as well as living specimens. Organisms that produce accretionary hardparts serve as environmental recorders during their lives. Variation in growth rates and repeating growth structures have been interpreted to reflect endogenous rhythms, physiological periodicity, or environmental cy- cles. Varying widths of growth increments have also been attributed to random ecological fluctuations (e.g., Kennish & Olsson, 1975; Peterson, 1983). The stable isotope com- position of growth layers is now being used in many pa- leobiological and paleoenvironmental studies (e.g., Tur- ekian et al., 1982; Williams et al., 1982; Roux et al., 1990; Kirby et al., 1998; Jones & Gould, 1999); and a few studies address the chemical content of the growth increments (e.g., Mutvei et al., 1994). Here we present the results of stable isotope and scler- ochronological investigations on the bivalve mollusks Chione (Chionista) fluctifraga (Sowerby, 1853) and Chi- one (Chionista) cortezi (Carpenter, 1864, ex Sloat MS) from the intertidal zone of the northern Gulf of Califor- nia, Mexico. We describe inter- and intra-annual growth patterns and growth rates and interpret them in order to 80° a, es or DALLAS eric, HOUSTON a 2 ¥ 7 MONTERREY @ O Figure 1. Sample localities in the Northern Gulf of California region. Samples were taken in mid-intertidal at low tide from North Orca (31°20.087'N, 114°52.957'W) Isla Montague (31°40.3'N, 114°41.4"W) and Isla Pelicano (31°45.7'N, 114°38.9'W). elucidate the life cycles and ages of the species. Intra- annual oxygen-isotope profiles provide further insight into temperature conditions during growth. MATERIALS AND METHODS More than 300 specimens of C. (C.) cortezi and C. (C.) fluctifraga were collected alive at low tide from the mid intertidal zone at three different localities in the northern Gulf of California, Mexico: North Orca, Isla Montague, ind Isla Pelicano (Figure 1). Collecting was done in late The Veliger, Vol. 45, No. 1 February 1997 and 1998, late May, early August, early November and early December of 1999. The tidal regime of the northern Gulf of California is semidiurnal with a mean tidal range of about 5 m. Average salinity of open Gulf water is 38%o + 2%oc in this area. Monthly average sea surface temperatures (SST) provided by satellite mea- surements (NOAA; http://www.cdc.noaa.gov/; WebWinds Java application, a software package to read the *.netcdf files, was obtained from http://webwinds.jpl.nasa.gov) vary between 15 and 30°C. Local temperatures may be 10 to 15°C higher or lower than those indicated by sat- ellite measurements (personal observation). Discrimination of the two species is often difficult. Ac- cording to Villearreal-Chavez et al. (1999), C. (C.) cortezi is geographically restricted to the uppermost part of the Gulf of California, i.e., 31°30’N, whereas C. (C.) fluctif- raga 1s more widely distributed. Both species are record- ed as present in the study area. According to-Keen (1971), C. (C.) cortezi is larger and has a more trigonal form than C. (C.) fluctifraga. Smooth and polished concentric ribs characterize C. (C.) fluctifraga. Fifty live specimens of C. (C.) cortezi were collected at North Orca (Figure 1) in early December 1999. Spec- imens were collected during four successive low tides in order to determine the time needed to produce the small- est shell growth increments. In addition, notching and staining experiments were conducted at the same loca- tion. Two-hundred specimens (120 C. (C.) cortezi and 80 C. (C.) fluctifraga) were held in buckets (also containing sediment from the collection site) in a tetracycline (1000 mg/L) or Alizarine Red solution (ambient seawater) in order to stain newly formed growth increments of the shells. Salinity ranged from 39 to 43%c during the exper- iment. Forty specimens were sacrificed every 6 hours. The flesh was removed from all shells immediately af- ter collection to prevent further shell deposition. After coating with epoxy resin, valves were cut along the axis of maximum growth using a low speed (Buehler Isomet) saw, ground on glass plates (600, 800, and 1000 grit pow- der) and polished on laps (9, 6 and 0.3 microns) in order to enhance the contrast of the microstructures. Valves were ultrasonically rinsed in deionized water after each polishing step to remove grinding powder. A caliper was used to measure the distances between major growth lines (i.e., annual increments) in radial cross-sections of 16 Chione (C.) cortezi and 18 Chione (C.) fluctifraga specimens (North Orca and Isla Montague material) to the nearest 10 wm using a reflected light bin- ocular microscope. Cumulative growth curves were cal- culated from the annual increment data, and each curve was fitted with a sigmoidal non-linear regression model referred to as ““MMF model’ in the software package CurveExpert Vs. 1.34 (available as shareware at http:// www.ebicom.net/~dhyams/cvxpt.htm): P(t) = (ab + ct*)/(b + t’), B. R. Schone et al., 2002 Page 47 where P(t) is the predicted increment width at time t and a, b, c, and d are fitted constants. Thirty Chione (C.) cortezi specimens from North Orca and one Chione (C.) cortezi specimen from Isla Pelicano were etched in a NaOH-buffered EDTA solution (0.25 m, pH 7.9) for 1 to 2 hours, carefully rinsed in water and acetone, and allowed to air dry. Etching increased the contrast of the growth increments. In addition, we prepared polished thin sections (thick- ness 30-50 pm) of five Chione (C.) cortezi specimens from North Orca and stained them with a 0.5% Rhoda- mine B solution for 3 minutes in the microwave at 50°C. This method stained the organic-rich microgrowth incre- ments and made their recognition easier. Microgrowth increment widths (i.e., higher order in- crements, from a few pm to 300 pm thickness) of one Chione (C.) cortezi specimen (IP1-A1R) from Isla Peli- cano were measured to the nearest 5 wm in radial cross sections under a reflective light microscope using an eye- piece scale. We used linear regression (growth increment width versus growth increment number) to estimate how increment width changed through 1 year. The purpose of linear regression is to remove the age trend (Cook & Kairiukstis, 1990). The growth index was calculated by dividing the observed increment width by the predicted increment width. These procedures are known as detrend- ing and indexing in dendrochronology (see Fritts, 1976; Cook & Kairiukstis, 1990). The growth index is a di- mensionless measure of how growth deviates from the average trend. A value of | indicates no deviation; values greater than | indicate more rapid growth than expected; values less than | indicate slower growth than expected. Jones et al. (1989) have applied this technique to inter- annual growth variation of bivalve mollusks. Here, we apply the technique to intra-annual growth variation. Specimen IP1-A1IR was rinsed several times ultrason- ically with deionized water prior to sampling for isotopic composition. The outer shell layer was sampled using a 300 pm drill under a binocular microscope. The number of increments sampled varied from three to 40. Each of the 22 drill holes yielded 50 to 200 wg of carbonate for isotopic analysis. A micromass automated carbonate ex- traction system was used to process the samples. 6'5O is reproduced relative to PDB on a NBS-19 value of —1.92%o. Precision is better than 0.1%c. . RESULTS Annual Growth Patterns and Growth Breaks We observed two seasonally distinct interruptions in growth in both species. Samples collected in late Febru- ary show a growth break (GB1, dark line, Figure 2d) near the ventral margin on the exterior shell surface as well as in radial cross sections. This pattern is more clearly developed in C. (C.) cortezi than in C. (C.) fluctifraga. No growth break occurs near the margin on specimens collected in November or December. At greater magni- fication (100), the higher order increments preceding GB 1 continuously decrease in width (Figure 2d). The na- ture of these higher order increments is described below in further detail. A striking feature in both Chione species is a several millimeter-thick purple zone consisting of numerous, very narrow (approx. 1—5 wm) higher order increments (Figure 2c, e). In older specimens, there is a growth break (GB2, Figure 2b) visible within this purple zone that is ex- pressed as a dark line on the outer shell surface. The thickness of this purple band varies with age and species. It is broader and less distinct in young specimens and it is more obvious in C. (C.) fluctifraga than in C. (C.) cortezi. The purple band is not seen after the last GB1 in May samples, but can be identified unequivocally at the ventral margin in specimens that were collected in early August. In these specimens, the purple band is thinner than in previous years recorded in the shell, suggesting that the GB2 was being deposited in early August. The width of higher order increments increases contin- uously after GB1, reaches a maximum of 230 wm about midway between GBI and GB2, and then decreases slightly before the purple zone. This pattern is character- istic for specimens smaller than 3 cm. There is an addi- tional small growth break in some larger specimens (> 4 cm) usually somewhere between GBI and the purple band. Growth rate decreases suddenly before this break and increases soon after. The interval between the end of the purple band and GB1 is characterized by wider (up to 120 wm) micro- growth increments. Microgrowth increment width in- creases rapidly at the end of the purple zone. In speci- mens collected in early December, the higher order in- crements near the ventral margin are considerably smaller than those in specimens collected in November. Growth Rate Increment widths between GB1’s of both Chione spe- cies decrease from the umbo to the ventral margin, in- dicating that growth rate decreases with age. However, the growth curves are distinct for each species (Figure 3). Note that growth data from different localities from spec- imens living at different times are included in this dia- gram. Therefore, despite varying environmental influenc- es, the overall growth patterns for each species remain essentially the same. Fitting the data with a sigmoidal growth function (MMF-model) returns very high corre- lation coefficients (r = 0.997, P < 0.05). Similar corre- lation coefficents have been reported from investigations of other species (Jones et al., 1989). The two species differ in their maximum ages. Where- as the maximum observed age of C. (C.) cortezi speci- mens is 8 years, the oldest C. (C.) fluctifraga specimens are almost 16 years old. The oldest C. (C.) cortezi spec- Page 48 The Veliger, Vol. 45, No. 1 Figure 2. Microgrowth patterns of Chione (Chionista) cortezi (Figures 2a—d; sample no. IP1-A1R, Isla Pelicano) and Chione (Chionista) fluctifraga (Figures 2e, f; sample no. NO3-A6L, North Orca) as seen on etched surfaces under reflected light microscope (a—d) and SEM (e, f) Growth direction is always to the right. a. Lunar day increments produced during spring of the 3rd year. Each lunar day increment is bordered by thick ridges (arrows). Faint ridges are sometimes visible between two thicker ridges. b. Arrows mark an annual increment in a later ontogenetic stage (6th year). The white line indicates the summer break (GB2). The spawning break is indicated by “s.” c. Slowdown of growth in the summer in an early ontogenetic stage (3rd year). Fortnightly cycles are indicated by arrows. d. Winterbreak (GB1, arrow) in the 3rd year. Note the narrow increments preceding the break and their increasing width after the break to the nght. e. Growth slowdown during hot summer. Lunar day increments are about 4% the width of those earlier in the spring of the same year. (shown in Figure 2f). The etch-resistant increments are broader than during the spring and fall. f. Lunar day increments (see Figure 2a for description). B. R. Schone et al., 2002 Chione (C.) cortezi a = 0.031098 b = 6.150633 c = 8.920858 Page 49 de 0573, Chione (C.) fluctifraga a = -27.288497 b = 0.47826582 c = 14.230518 d = 0.39698264 cumulative growth [cm] = length number of specimens 8 10 12 14 age t [year] Figure 3. Growth curves of Chione (Chionista) cortezi and Chione (Chionista) fluctifraga. Maximum observed ages in Chione (Chion- ista) fluctifraga are lower than in Chione (Chionista) cortezi. Chione (Chionista) cortezi grows faster than Chione (Chionista) fluctifraga. imens, however, are generally 4% larger than the oldest C. (C.) fluctifraga specimens. The ventral margins of the oldest C. (C.) fluctifraga specimens are bent to the inside: the growth direction in this species changes from an an- terior-posterior direction to growth directed toward the opposite margin along the commissure. With increasing age, the shell margin of C. (C.) fluctifraga becomes ob- tuse, and the convexity of its shell increases sharply as has been demonstrated by Zolotarev (1980) for other spe- cies. As a result, the length/height relationship of old specimens is higher than that of young specimens. Higher Order Growth Increments Cross-dating (matching increments in different speci- mens, see Fritts, 1976) of the most recently produced in- crements on the ventral margin of 14 Chione (C.) cortezi and eight Chione (C.) fluctifraga specimens collected at North Orca in early December 1999 indicates that every high-low tidal cycle results in a couplet of one narrow etch-resistant and one broader, deeply etched increment. A high-low tidal cycle comprises approximately 12.4 hours. In specimens collected during the morning low tide, the etch-resistant increment at the commissure is considerably less distinct than in specimens collected dur- ing afternoon low tide. The time interval between two thick etch-resistant growth increments 1s approximately 24.8 hours. In the paleontological and biological litera- ture, the term lunar day is often used to describe the time interval between these microgrowth increments (e.g., Evans, 1972; Pannella, 1976). A lunar day is the amount of time required for one rotation of the Earth on its axis, with respect to the Moon. 0 0.5 1 1.5 2 2.5 growth index Figure 4. Relationship between tidal range and growth index. Maximum growth rate (here shown for Chione (Chionista) cor- tezi, shell IP1-A1R) corresponds to low tidal range, 1.e., neap tides. Note that the influence of temperature on growth has not been extracted from the growth index. Counting lunar days from the ventral margin of three Chione (C.) cortezi specimens (one from Isla Pelicano and two from Isla Montague) back toward the umbo re- veals a growth pattern that coincides with lunar tidal cy- cles similar to what was noted by Evans (1972) for other species. Tidal range and shell growth are negatively cor- related (Figure 4). Maximum growth rate occurs during neap tides when tidal range is low. Two relatively narrow lunar day increments form in a fortnightly cycle (‘‘3rd- order layers’? sensu Barker, 1964). They are most prob- ably formed during spring tides. The small increments are accompanied by growth depressions on the external shell surface (Berry & Barker, 1968). Twenty stained (tetracycline 1000 mg/L, Alizarine Red; bucket experiments) specimens of both Chione spe- cies show a yellow-orange (tetracycline under UV-light) or reddish band, whose widths correspond to the incre- ments formed during exposure to the stains. These ex- periments confirm the results found by field sampling on consecutive tides (described above). Only specimens of age-class one and two, however, showed noticeable shell growth in December 1999 when these experiments were conducted. All these findings enabled us to date the major events in the shell with precision to the nearest fortnightly cycle. However, the total number of lunar days within an annual increment was always less than the expected number (353.25) of lunar day increments in a solar year. The total number of lunar day increments in three specimens of C. (C.) cortezi was 253, 291, and 307. Stable Isotope Variation The oxygen isotope composition of a shell is a function of the ambient temperature and 8'8O of the water (which in turn is determined by evaporation rate and the amount of freshwater input) in which the individual is living. Shells were collected at times when the Colorado River did not flow into the Gulf of California. Thus changes in The Veliger, Vol. 45, No. 1 shell 6'8O are a function of changes in temperature and evaporation but not fluvial influx (see Dodd & Stanton, 1990, for an extensive discussion). 6'*O values vary with the inverse of temperature: high 5'*O values indicate low temperatures and low 6'8O values indicate high temper- ature. For aragonitic mollusks a temperature increase of 4.7°C results in an isotopic shift of 1% (Grossman & Ku, 1986). 6'8O values in the third year of growth of C. (C.) cor- tezi specimen IP1-A1R range from 0.91 to —2.47 (Figure 5c), corresponding to a temperature of 15.5 to 30.5°C. Values are highest in shell material deposited during win- ter and are lowest in the purple band deposited between mid July and mid September. DISCUSSION Annual Growth and Growth Breaks Periodic, distinct growth patterns (“‘biochecks”’ of Hall et al., 1974), 1.e., seasonal growth halts, growth retarda- tion, or structural change of material form the basis for a chronology, based on shell growth. Biochecks segment the growth increment pattern into time intervals of ap- proximately equal duration and can be used for many purposes, including determining the age of an individual bivalve mollusk. Because seasonal events do not recur at exactly the same time each year, the number of increments per annual increment may differ. Therefore, Hall et al. (1974) intro- duced the term “‘median date of the deposition of bio- checks.”’ Biochecks are usually related to temperature ex- tremes (low or high; e.g., Davenport, 1938; Pannella & MacClintock, 1968; Kennish & Olsson, 1975; Clark, 1975; Jones, 1983) and to spawning events (Jones, 1980; Sato, 1995; and references therein). Caution should be exercised when using reproduction biochecks in different specimens for dating. The dates of reproduction breaks in Chione (C.) fluctifraga vary considerably between indi- viduals (Martinez-Coérdova, 1988). This has also been shown for other bivalve mollusks (e.g., Coe, 1948; Coe & Fitch, 1950; Sato, 1995). Depending on the seasonal temperature cycles, one or two temperature-mediated biochecks can be present: a summer break and/or a winter break (e.g., Koike, 1980; Clark, 1979; Sato, 1995; Jones & Quitmyer, 1996). The specimens studied here show both a winter and a summer biocheck (compare Koike, 1980 and references therein). The winter break represents a cessation of growth. The summer break represents a slowdown and/or a cessation. The growth slowdown in summer 1s macroscopically expressed as a purple band (summer band). In some shells a growth halt is present within the purple band (summer break, GB2). The shutdown of growth in the cold season is called a winter break (GB1). Additional support for this interpretation comes from counting the lunar day incre- ments in specimens collected during different seasons to B. R. Scho6ne et al., 2002 Page 51 9; 250 200 a 150 t width [pm 100 50 Incremen 0 growth index 5180 [%o] Temperature [°C] Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Figure 5. Comparison of growth rate and oxygen isotope composition of Chione (Chionista) cortezi (IP1-A1IR) and sea surface temperatures. a. Microgrowth increment width (lunar day increment width). Only those data are depicted for which oxygen isotope composition has been determined. A linear fit has been applied to the raw data in order to extract the inherent age trend. b. Age- detrended growth data. The residuals were calculated from the data in Figure 5a by dividing the measured by the predicted (linear fit) data. c. Oxygen isotope data of selected increments. d. Monthly sea surface temperatures (SST) based on satellite observations of the sampled region during growth of Chione (Chionista) cortezi. date the biochecks. In the Gulf of California, unfavorable temperature extremes for Chione’s growth are reached during both summer and winter. Because these tempera- tures can be reached more than once during each season, there may sometimes be several growth halts within a winter or summer band. Annual reproduction breaks occur in specimens 3 years old or older. These show the characteristic microgrowth pattern described by Kennish & Olsson (1975) and Sato (1995) for reproduction breaks, namely abruptly smaller increment widths that preceed the break followed by broad increments afterward (Figure 2b). The interpreta- tion of these late spring or early summer growth bio- checks as reproduction events is reinforced by counting Page 52 lunar day increments, e.g., most specimens of both spe- cies start their first year of growth in late spring or early summer, indicating that spawning occurred shortly before. Of all collected specimens in early November and De- cember only 10 are clearly younger than 2 months, in- dicating that spawning in late summer is rare. Histologic studies on gonad development of Chione (C.) fluctifraga specimens by Martinez-Cérdova (1988) also indicate spawning in spring. Growth Rate Growth curves for the two Chione species, based on annual growth increment measurements, are similar to those published for other bivalve mollusk species (e.g., Sato, 1994, 1995; Hall et al., 1974; Thompson et al., 1980; Jones et al., 1978). Rapid growth occurs during early ontogenetic stages, and growth rates decrease as the individuals mature (Figure 3). This pattern is best de- scribed with a sigmoidal growth equation. Other investi- gators have found an exponential relationship between age and growth rate in various bivalve mollusk species (von Bertalanffy, 1934; Hall et al.. 1974; Richardson et al., 1980; Jones et al., 1989; Mutvei et al., 1994). Higher Order Growth Increments Staining experiments and specimens collected on con- secutive tidal cycles reveal unequivocally that a couplet of two etch-resistant increments and two deeply etched increments (Figure 2a, f) are produced each lunar day. The etch-resistant increments are more prominent if high temperatures prevail at low tide (Figure 2e). The width of the deeply etched increments increases with tempera- ture, but is reduced above and below specific temperature extremes, both cold and warm (see below). Crabtree et al. (1980) found that growth increments in C. (C.) fluctifraga are a poor indicator of time. Crabtree et al. (1980) conducted notching experiments on C. (C.) fluctifraga specimens. They concluded that ‘‘the line counts did not agree well with the number of days in the growth period” between notching and recovery. Further- more, they found that there was no “‘consistency in growth line counts”? both between different counters and between specimens of different age classes. However, a careful re-examination of the young specimen depicted in figure 8 of their paper shows 45 to 47 couplets consisting of two dark and two light increments. This should cor- respond to 45 to 47 lunar days consisting of 90 to 94 dark growth lines, although the six persons in their experiment counted only 56 to 74 lines (i.e., 23 to 37 lunar days). Our recounts match the expected number of increments (~48 lunar days) very well. Furthermore, recalculation of the tidal increment cycles (with wxtide25, Windows program available at http://www. geocities.com/Silicon Valley/Horizon/1195/wxtide32.html) indicates that the slight depressions (= deeply etched in- The Veliger, Vol. 45, No. 1 crements) between the growth ridges (etch-resistant in- crements) begin to form at or just after neap tides (Crab- tree et al., 1980: figure 8). Berry & Barker (1968) were the first to suggest a fortnightly periodicity in the for- mation of external growth ridges in Chione. The time interval that a lunar day increment—whether solar (light/dark cycle) or tidal (Barker’s, 1964, ‘‘4th-or- der layer’ )—represents is controversial. There is little ev- idence when and in which time period the etch-resistant and deeply etched parts of the increments are produced (but see Richardson et al. 1981). Our experiments were not able to clarify this problem. Stable Isotope Variation Values of 5'8O vary inversely with ambient sea surface temperatures (Figure 6c, d). The 3.38%c annual range in 580 values corresponds to a 15.9°C temperature range (3.38%0o X 4.7°C/%c, see Grossman & Ku, 1986). This range is greater than the 11.4°C maximum difference in mean monthly SSTs observed by satellite. However, the SST data are monthly averages, and the difference be- tween maximum and minimum daily temperatures will exceed the difference in monthly averages. The isotopi- cally determined temperature range represents the range of temperature during which shell growth occurs, not the total range during the year, because growth ceases during seasonal temperature extremes. Temperature Control of Growth Rate As discussed above, the growth rate of Chione (C.) cortezi varies seasonally (see Figures 5a, b). Growth rate is high from March to June, decreases from July to Sep- tember, increases again in September and October, slows in November and December, and halts during late Decem- ber. Growth starts again late in February. This pattern suggests that both low and high temperatures inhibit growth in this species. Maximum growth rates occur when monthly average temperatures are between 21 and 24°C (Figure 6). Ninety-five percent of the annual incre- ment width is formed between 16.7 and 29.3°C (monthly average SST, satellite data, Figure 5d). Isotopically de- rived estimates of temperature confirm this range. Winter growth breaks (GB1) occur when temperatures drop be- low this range and summer breaks (GB2) occur when temperatures exceed this range. SUMMARY AnD CONCLUSIONS Specimens of Chione (C.) fluctifraga and Chione (C.) cortezi show both a winter and summer biocheck. Both biochecks are useful for ontogenetic age determination. The maximum observed age for Chione (C.) fluctifraga is higher (15 years) than that of Chione (C.) cortezi (8 years) even though Chione (C.) cortezi grows to a larger size. Chione (C.) fluctifraga grows much more slowly than Chione (C.) cortezi. B. R. Schone et al., 2002 Page 53 lunar day growth index \ 12 (7 27 ISST [°C] 32 Figure 6. Growth indices (lunar days) and SST fitted with a Gaussian function. The dashed lines indicate the upper and lower growth temperature thresholds in Chione (C.) cortezi and Chione (C.) fluctifraga. Growth breaks accompanied by dark lines on the ex- terior shell surface are commonly observed within the winter and summer bands. Furthermore, some specimens exhibit a spawning break in late spring. Microgrowth increments form with tidal rhythms and are useful for dating special events (summer, winter, tidal cycles, storms, spawning, etc.). Maximum growth rates occur during April to June and again during October. Growth occurs between February and December and is suppressed by temperature extremes both during the cold season and the hot summer period (mid July to mid September). Acknowledgments. This study has been made possible by a postdoctoral scholarship (Lynen program) by the Alexander-von- Humboldt foundation (to B.R.S.) and NSF grant EAR 9805165 to (K.W.F). Reynolds sea-surface temperature (SST) data were obtained by the NOAA-CIRES Climate Diagnostics Center, Boulder, Colorado, at http://www.cdc.noaa.gov/. We are grateful to Sean Connolly and Jon Pelletier for helpful discussions and to Dave Bentley for advice in staining thin sections. We thank Barry Roth and an anonymous reviewer for comments that im- proved the manuscript. This is C.E.A.M. (Centro de Estudios de Almejas Muertas) publication no. 39. LITERATURE CITED Barker, R. M. 1964. Microtextural variation in pelecypod shells. Malacologia 2:69—86. Berry, W. B. N. & R. M. Barker. 1968. 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This experiment investigated the circumstances under which whelks will attempt to feed upon the blue mussel Mytilus edulis. Whelks did not attempt to feed upon intact mussels after a period of starvation of 2 weeks, but were significantly more likely to attempt to feed after 6 weeks starvation. However, because of the mussel’s ability to close so tightly, this was usually unsuccessful. Whelks starved less than 6 weeks attempted to feed only on mussels that had sustained tissue damage. Whelks were also attracted to water from injured mussels. This suggests that, despite the relatively high abundance of blue mussels, whelks feed on these mussels only opportunistically. This supports the argument that B. undatum is primarily a scavenger and has only limited success as a predator upon healthy bivalves. INTRODUCTION The marine prosobranch gastropod, the waved whelk Buccinum undatum (Linnaeus, 1758), is abundant in the North Atlantic. It tolerates a wide range of salinity and is found in depths as shallow as the mean low water mark and as deep as 1000 m (Brock, 1936; Fretter & Graham, 1962). It is considered to be a carnivore with a tendency to scavenge (Blegvad, 1915). Prior studies of stomach analysis have shown the whelk’s diet to be dominated by bivalve mollusks (Nielsen, 1975). After an extensive study of Buccinum predation on many species of bivalves, Nielsen (1975) concluded that only rarely were the whelks able to overcome healthy bivalves of most spe- cies—including Mytilus edulis, the blue mussel. The whelk’s method of attack is to crawl upon the shell and orient itself so that the anterior margin of the foot is in contact with the ventral edge of one of the shells of the bivalve. If the bivalve is open after this procedure, or if it reopens again after the whelk has settled, the whelk suddenly contracts and forces the lip of its shell in be- tween the valves of the bivalve, preventing its closure. If the resulting opening is large enough, the whelk will then insert its probiscis and begin tearing flesh with its radular apparatus (Nielsen, 1975). Nielsen observed that Buccin- um was rarely able to overcome healthy bivalves of most species. Mytilus edulis (Linnaeus, 1758) and Modiolus modiolus (Linnaeus, 1758) were able to close tightly enough that the whelks usually gave up any attempts to *Address for correspondence: John C. Thompson, % Michelle P. Scott, Department of Zoology, University of New Hampshire, Durham, New Hampshire 03824, USA; e-mail: oceanjohnny @ yahoo.com open and crawled away. At times during an attempt to open, the mussels would close so tightly upon the lip of the whelk’s shell as to cause it to break. One can find many whelks in a population with such scars, indicating that the process of preying upon healthy bivalves is dif- ficult, dangerous, and potentially energetically expensive. This experiment examined the circumstances under which whelks will attempt to feed on blue mussels. I ex- amined their motivation to feed after 2 and 6 weeks of starvation to test the hypothesis that whelks should only attempt to feed upon healthy blue mussels after a suffi- cient period of starvation. I also examined the differences between whelk feeding attempts on mussels that had sus- tained tissue damage and those that had not sustained tissue damage. Finally, I examined the olfactory cues nec- essary to stimulate feeding behavior. MATERIALS anpD METHODS Whelks were collected from the subtidal Gulf of Maine waters in the vicinity of the Isles of Shoals, New Hamp- shire; along the coast of New Castle, New Hampshire; and in Eastport, Maine. They were kept in filtered sea- water at 10°C. Each whelk was used once in experiments and then released. The prey species Mytilus edulis was collected from intertidal and subtidal locations along the New Hampshire and Maine coastlines. Prey specimens were also kept in filtered seawater at 10°C. Mussels used were between 1.2 cm and 6.3 cm in length. The whelks were fed fresh, pre-opened M. edulis at a designated time prior to each experiment. This was fol- lowed by a period of food deprivation to establish a uni- form level of hunger in all whelks used in that particular trial. Page 56 The Veliger, Vol. 45, No. 1 Table 1 Feeding cues for Buccinium undatum. 2 weeks starvation 6 weeks starvation Effect of hunger Feeding stimuli MgCl2 Mytilus treatment Healthy Mytilus Nicked tissue Mytilus Effect of prey- specific olfactory Mytilus extract stimuli Seaweed extract # Attempts to feed # No attempts to feed 0) 18 5 3 0) 5 (0) 12 4 4 Arousal No arousal 4 0) 0 8 Whelks’ responses were scored in four categories: no attempt to feed, unsuccessful attempt, successful attempt, and ‘‘arousal,’” which was indicated by a major postural change or locomotion in response to a stimulus. Experiment A—Effect of Hunger Whelks (n = 26) were each isolated into 9.45 L aquar- iums filled with filtered seawater. Each aquarium had an air stone. Whelks were fed once with a pre-opened, me- dium-sized (relative to the whelk) M. edulis, which they consumed. They were then kept without food for 2 or 6 weeks before the feeding trial. The effect of hunger was then examined by presenting individual whelks with a live, healthy M. edulis, and observing them for 2—3 hours for any attempts to feed. Experiment B—Effect of Prey Condition In this experiment, whelks that had not been fed for 3 weeks were either given a live, healthy, normal Mytilus or one that had been weakened using a 3.5% solution of MgCl, in seawater. The mussels were placed in the treat- ment solution for 15 minutes. This treatment affected the nervous system of the mussels, so that when touched or handled they remained in an open relaxed position and did not close their valves. This condition lasted 30 min- utes, which was sufficient for the experiment. Outcome was scored in the same fashion as in experiment A. I examined responses of whelks that had not been fed for 3 weeks that were given healthy mussels, and whelks given mussels with slight tissue damage. The mussels were nicked slightly on their mantle with a razor, but their adductor muscles were left intact. Outcome was again scored in the same fashion as in experiment A. Experiment C—Effect of Chemical Cues Chemoreception is the primary means by which whelks locate food (Brock, 1936). To identify the source of ol- factory cues that induce feeding, I used mussel “‘scent.”’ fo produce mussel scent, a mussel was opened with a razor and placed in 25 mL of distilled water for approx- imately 20 minutes. Seaweed “‘scent’’ was used as a con- trol and was created by crushing a few grams of Lami- naria sp. in 25 mL of distilled water. Whelks were not fed for 3 or 5 weeks before testing. Whelks were placed in the center of their respective tanks. Next, 1 mL of either mussel “‘scent’? or seaweed (Laminaria sp.) extract was added to the water in the vicinity of the whelk. Since no actual prey items were present during this experiment, whelk responses were scored as either “‘arousal” or no response. Aroused whelks showed an immediate postural change often followed by locomotion directed into the current and toward the scent plume. Unresponsive whelks remain stationary and relaxed with their shell resting upon the substrate. RESULTS Experiment A: Whelks (n = 18) deprived of food for only 2 weeks never attempted to feed, whereas those (n = 8) starved for 6 weeks were significantly more likely to attempt to feed on healthy mussels (Fisher’s exact test P = 0.001, Table 1). Experiment B: Whelks made no attempt to feed on mus- sels subjected to a MgCl, treatment (n = 5) or untreated mussels (n = 12). However, when offered mussels that had sustained mantle tissue damage (with the adductor muscles still intact), significantly more whelks attempted to feed (n = 8) (Chi-square goodness-of-fit test P = 0.002, Table 1). Experiment C: Whelks showed a significant response to prey-specific odors. All showed a typical arousal response to mussel scent (n = 4), and none did to seaweed scent (n = 8) (Fisher’s exact test P = 0.002, Table 1). DISCUSSION Behavior is contingent upon both the external conditions and the internal state of the animal. In foraging, the de- cisions made regarding when and how to feed often re- J. C. Thompson, 2002 flect the hunger of the animal—the internal variable, and the food availability—the external variable. In this case, whelks preferred damaged prey, but when faced with the risk of starvation as a result of restricted food availability, there was a shift in the foraging decision. That is, the hungry whelks were more likely to attempt to open a healthy mussel. Nielsen (1975) showed that healthy mussels have an excellent defense against whelk predation in their ability to close their valves tightly for long periods of time. Opening an intact mussel is energetically expensive and presents a risk of injury. Thus feeding upon a healthy bivalve does not constitute as large a net energy gain as feeding upon a damaged bivalve. This suggests two things: first, injured prey would be preferred to intact prey; and second, the whelk would attempt to feed on a healthy bivalve only as the risk of starvation increases. Both of these predictions are supported by the data. The inverse relationship between hunger and selectiv- ity is widespread. Feeding preferences of another preda- tory gastropod, the dogwhelk Nucella lapillus (Linnaeus, 1758), have also been shown to be influenced by star- vation. Dogwhelks restricted from feeding were more likely to feed upon a patch of barnacles (Vadas et al., 1994). Likewise, a study of the predatory snail Acanthina spirata (de Blaineville, 1832) showed the species to be less selective between two different barnacle species when starved (Perry, 1987). The behavior of Buccinum undatum can be fitted to a risk-sensitive model of behavior. Here, the term risk re- fers to probabilistic variation in prey (Stephens & Krebs, 1986). Caraco et al. (1980) demonstrated that an animal’s energy budget can predict whether it is risk-averse or risk-prone. That is, an animal on a negative energy budget (a hungry whelk, for example) will prefer variable food rewards. In this case, a variable food reward is a healthy mussel. An attempt to open it will result in either a large gain in energy or none at all. On the other hand, an an- imal on a positive energy budget will prefer less variable food rewards—in this case, a damaged mussel for which there is no chance of failure if the whelk attempts to feed. Stated simply, hungrier animals are more impulsive and thus less selective with regards to foraging opportunities (Synderman, 1983). It is possible that starvation, in ad- dition to reducing the selectivity of whelks, has a negative effect on the successes of attacks upon bivalves. If this is the case, there may come a point at which prey selec- tivity increases again, as any further attempts to open healthy bivalves would prove unsuccessful. An investi- gation on the effects of starvation and diet of another species of whelk, Bullia digitalis, demonstrated that star- vation had a detrimental effect upon the feeding process in some cases (Stenton-Dozey et al., 1995). The cues a whelk uses to make a decision to feed are important. Odor cues from damaged mussel tissue are Page 57 sufficient to trigger feeding behavior, whereas odor cues from undamaged tissue are not. Although the mussels treated with MgCl, were defenseless, no whelks attempt- ed to feed, even after investigating the mussel and en- countering no defensive response. However, damaged mussels that could still close tightly were attractive prey. Chemosensory cues from the damaged tissue are impor- tant to stimulate feeding behavior, whereas visual or tac- tile cues seem to be of little importance. When mussel scent alone was presented, all whelks showed the postural change associated with the stimulus of the mussel extract that suggested interest in feeding. None showed any in- terest or response to an equivalent addition of seaweed extract to the water, demonstrating that whelks distinguish prey odors from non-prey odors in the water, and react accordingly. Acknowledgments. I thank Dr. Michelle P. Scott for her support, guidance, and insight concerning the world of research in animal behavior. I also thank Dr. Larry G. Harris who has been more than willing to offer advice, space in his laboratory, equipment, and his time. I also thank Michael Lesser for comments on the manuscript, Chad Sisson, Suchana Chavanich, and Jonathan Payne for their help in diving and the collection of animals, and Tricia Madigan for assistance in caring for my whelks. Finally, I thank the Undergraduate Research Opportunities Program of the University of New Hampshire for providing the necessary funding. LITERATURE CITED BLEGVAD, H. 1915. Food and conditions of nourishment among the communities of invertebrate animals found on or in the bottom in Danish waters. Report. Danish. Biological Station 22:41-78, table in Beretning til Ministeriet for Landbrug og Fiskeri fra Den Danske Biologiske Station 22: appendix: Analyser af Mave- og Tarmindhold. 45 pp. Brock, E 1936. Suche, Aufnahme und enzymatische Spaltung der Nahrung durch die Wellhornschnecke Buccinum unda- tum L. Zoologica, Stuttgart 34 (5):1—136, 1 pl. CarRAco, T., S. MARTINDALE & T. WuHITTAM, 1980. An empirical demonstration of risk-sensitive foraging preferences. Animal Behavior 28:820—830. FRETTER, V. & A. GRAHAM. 1962. British Prosobranch Molluscs. Ray Society: London. 755 pp. NIELSEN, C. 1975. Observations on Buccinum undatum L. at- tacking bivalves and on prey responses, with a short review on attack methods of other prosobranchs. Ophelia 13:87— 108. Perry, D. M. 1987. Optimal diet theory: behavior of a starved predatory snail. Oecologia (Berlin) 72 (3):360—365. SNYDERMAN, M. 1983. Optimal prey selection: the effects of food deprivation. Behaviour Analysis Letters 3:359—369. STENTON-Dozey, J. M. E., A. C. BROWN & J. O’RIAIN. 1995. Effects of diet and starvation on feeding in the scavenging neogastropod Bullia digitalis (Dyllwyn). Journal of Experi- mental Marine Biology and Ecology 186(1):117—132. STEPHENS, D. W. & J. R. Kress. 1986. Foraging Theory. Prince- ton University Press: Princeton. 245 pp. Vapas, R. L. Sr., M. T. Burrows & R. N. HuGues. 1994. For- aging strategies of dogwhelks, Nucella lapillus (L.): inter- acting effects of age, diet and chemical cues to the threat of predation. Oecologia 100(4):439—450. The Veliger 45(1):58—64 (January 2, 2002) HE VBLIGER © CMS, Inc., 2002 Larval Development, Precompetent Period, and a Natural Spawning Event of the Pectinacean Bivalve Spondylus tenebrosus (Reeve, 1856) P ED PARNELL* Department of Oceanography, University of Hawaii, 1000 Pope Road, Honolulu, Hawaii 96822, USA Abstract. The artificial induction of spawning, and the development of larval Spondylus tenebrosus, a spondylid pectinacean bivalve, is described. A combination of warming and injections of serotonin into the adductor muscle of these animals produced spawning within 1.5 hours. Larvae were cultured at temperatures ranging from 22—24°C. Pedi- veligers were first observed within 12 days of fertilization, and settlement was first observed 21 days after fertilization. Pediveligers that were not allowed to settle were healthy 60 days after fertilization, when culture ended, indicating that larval S. tenebrosus can delay settlement, and remain planktonic for at least 2 months. In addition, a spawning event of natural populations on the southern shore of Oahu, Hawaii was indirectly observed. This spawning event occurred during a period of maximum annual temperature, suggesting that warming may be a natural spawning cue for Spondylus tenebrosus. INTRODUCTION Spondylus tenebrosus (Reeve, 1856), a spondylid pectin- acean bivalve, is a commonly recruiting bivalve in Ha- walian coastal waters (Bailey-Brock, 1989). S. tenebrosus occurs in Australia, and the Gilbert, Marshall, and Ha- waiian Islands (Kay, 1979). In Hawaii, it mainly occupies vertical surfaces of natural and artificial reefs, and the upper surfaces of holes and small caves (Thorsson, 1987). It occurs from the shallow subtidal zone to at least a depth of 40 meters. Pectinacean larval development is similar to that ob- served in many bivalves (Cragg & Crisp, 1991). Gametes are spawned into the water column, and fertilization is external. Cleavage stages develop into mobile ciliated trochophores. The first shelled stage is prodissoconch I, and it is during this stage that the larvae first feed on phytoplankton. Prodissoconch II (umbone) larvae are characterized by the initiation of umbone development and the appearance of commarginal growth lines. The pe- diveliger stage, identified by the presence of a foot, is competent to settle. Pediveligers may leave the water col- umn and crawl on the bottom using this foot prior to settlement. The larval developmental period of pectinaceans, as observed in previous lab studies, varies with temperature and salinity, and among species. Delayed growth and de- velopment of pectinacean larvae have been observed at decreased temperatures (Beaumont & Budd, 1982). Pec- tinacean precompetent periods range from 14 days, for * Present address: Scripps Institution of Oceanography, Marine Life Research Group, University of California, San Diego, La Jolla, California 92093-0227, USA; e-mail: dparnell@ucsd.edu the tropical pectinacean Amusium pleuronectes (Belda & Del Norte, 1988), to more than 42 days for the temperate pectinacean Chlamys hastata (Strathmann, 1987). Although larvae of Spondylus tenebrosus are common in the Hawaiian coastal plankton throughout the year, the larval development of this species has not been previ- ously described. The period between the initial release of gametes and the development of larvae that are capable of settlement is referred to here as the precompetent pe- riod. The goal of the present study was to determine the minimum precompetent period of S. tenebrosus, and thus determine the minimum period that larvae are planktonic and subject to dispersion by circulation. This information was needed to supplement a field study of benthic inver- tebrate recruitment pattern forced by the interaction of circulation, larval planktonic period, and adult distribu- tion (work in progress). MATERIALS ann METHODS Broodstock Adult S. tenebrosus were collected twice from an ar- tificial reef off Waikiki Beach (southern shore of Oahu, Hawaii) at a depth of 35 meters using SCUBA. Six in- dividuals were collected on 10 August 1996 and were dissected immediately to check for gonad condition. Five individuals had ripe gonads (four females and one male). This initial collection was conducted to determine if an- imals were available and, if so, to check their gonad con- dition. A second collection was conducted after prepara- tions were made to culture adults and larvae. Sixteen adults were collected on 21 September 1996 for brood- stock. These animals were transported to the lab in a 128 L cooler, half filled with surface water from the collection P. E. Parnell, 2002 site (T = 26.7°C). The animals were cleaned of fouling algae and invertebrates using a plastic scrubbing pad and a putty knife. They were then placed in a 70 L aquarium filled with seawater at ~26°C. The aquarium temperature was kept constant until spawning induction was attempted 2 hours later. Spawning The broodstock was placed in a 3 L glass bowl filled with 0.2 ym filtered seawater (FSW) for spawning (salin- ity ~ 34). Spawning induction was first attempted by in- jection of 0.5 mL of a 2 mM serotonin solution (Strath- mann, 1987; Monsalvo-Spencer et al., 1997; Rhee & Da- vis, 1997). Serotonin was injected through ~2 mm holes that were drilled through the anterior valves so that ad- ductor muscles could be injected; one hole was drilled per animal. Injections were not possible without drilling because the animals rapidly closed their valves upon sensing any motion. Several animals opened and closed their valves quickly within 2 minutes of injection, but no gametes were seen exiting the mantles. No spawning was observed for 2 hours. The animals were then warmed from 26.2°-35.0°C over a 1-hour period (salinity ~ 34) as a second attempt to induce spawning; spawning did not occur. Five individuals were then dissected to obtain gametes, but all gonads were empty. It was therefore like- ly that the S. tenebrosus population on the artificial reef off Waikiki had spawned since the first collection of 10 August. Two different populations of S. tenebrosus in Mamala Bay were then sampled on 23 September to check for gonad condition. Five animals were taken at a depth of 3 meters from a sunken barge off the west end of Waikiki Beach, and five animals were collected at a depth of 30 meters from a natural reef off Ewa Beach. These animals were dissected upon return to the lab, and none had ripe gonads. The 11 individuals that remained from the 21 Septem- ber collection were maintained in a 60 L aquarium filled with natural seawater at ~26°C. The animals were fed a mixed diet of phytoplankton in an attempt to return them to spawning condition. The algal diet was composed of dense suspensions (algal concentrations were not quanti- fied) of Jsochrysis galbana (Tahitian strain) and Skeleto- nema costatum (Greville) at a temperature of ~26°C. On 21 November (60 days later), the animals were reinjected with serotonin solution as before and were monitored for 2 hours. No spawning occurred. Warm shock was then attempted as before. After warming, water in the spawn- ing pan was allowed to cool. Several individuals spawned within minutes of each other, beginning approximately 1.5 hours after warming began. It was not possible to determine how many animals had spawned due to the turbidity created by spawning. The temperature in the pan was 28.3°C when the animals spawned. Page 59 Tees aw ‘Yank (’ | 6 Y S a ) 74 Air 0 Uj i Se a 400 ml ' VS tri-cornered ——7?| ( [XR es flask | 75%). Developmental stages of 20 haphazardly chosen live larvae from three randomly chosen beakers were not- ed at 1 to 3 hour intervals for the first 48 hours. After that, at least 200 larvae were placed in each of 12 600 mL culture vessels. The culture vessels were continually stirred using air to lift water from the bottom of the vessel and return it at the surface (Figure 1). These larval culture vessels were designed by Michael Hadfield, and are de- scribed by Strathmann (1987:16). This design reduces the number of larvae stuck at the water’s surface. Twenty haphazardly chosen larvae were removed from three ran- domly chosen culture vessels every 2 to 3 days for mea- surement of the largest dimension and determination of developmental stage. This method of determining larval size and developmental stage was used to minimize in- Page 60 Table 1 Numerical codes of developmental stages for descriptive statistical analysis. Numerical Larval stage code Fertilized egg 0) First Cleavage (includes all cleavage stages) 1 Blastula 2 Gastrula 3 Trochophore 4 Prodissoconch I (Straight-Hinged) 5 Prodissoconch II (Umbo Veliger) 6 Pediveliger 7 dividual larval handling. The number of culture vessels decreased as larvae died or settled and larvae from dif- ferent culture vessels were combined. Developmental stages were numerically coded for descriptive statistical analysis (see Table 1). Salinity in the vessels was ap- proximately 34, and the temperature varied between 22° and 24°C. Vessel seawater was changed every | to 2 days, and dead or abnormal larvae were removed. Larval Feeding and Algal Culture Larvae were fed dilute suspensions of [sochrysis gal- bana and Skeletonema costatum (log-growth stage) be- ginning when larvae reached the first feeding stage (straight-hinged stage) 24 hours after fertilization. The concentrations of algae in the feeding suspensions were not determined. However, it was apparent that the larvae were feeding because visual inspections showed their guts were full of algae. Enough algae were added to the ves- sels to keep larvae guts full throughout the culture period. Isochrysis galbana and S. costatum were cultured in auto- claved f/2 medium-enriched seawater (Bidwell & Spotte, 1985:305) under continuous illumination by a cool white fluorescent light in aerated culture flasks. Settlement Shell fragments of adult S. tenebrosus were placed into three randomly chosen larval culture vessels after the first pediveligers appeared in the samples in an attempt to in- duce settlement. The shell fragments were obtained from adults that were crushed minutes before the settlement experiments began. Larvae were not counted in settle- ment vessels; instead, the cumulative number of settlers was counted on the days that developmental stage and size data were recorded. Cumulative counts of settlement were approximate due to the complex surface topography of shell fragments. Shell fragments were not added to the remaining culture vessels in order to determine the ability of S. tenebrosus to remain competent for prolonged larval The Veliger, Vol. 45, No. 1 periods. Shell fragments were finally added to these ves- sels 2 days before the end of the culture experiment. Lar- vae were cultured for a total of 60 days after fertilization. Field Temperature Record Warming is a spawning cue for many species of bi- valves (Strathmann, 1987) and pectinaceans specifically (Cragg & Crisp, 1991). Therefore, an oceanic temperature record was needed to determine if a warming event oc- curred when S. tenebrosus spawned in Mamala Bay be- tween 10 August and 21 September. However, no tem- perature record was available for the Bay. Alternatively, a temperature record from a C-MAN (Coastal-Marine Automated Network) buoy 51026 (21°21'06"N, 156°55’ 54”W), located 17 km north of Molokai and ~ 90 km from Mamala Bay, was obtained from the National Oceanographic Data Center’s online archive. The buoy temperature record provides a useful indicator of regional warming events lasting several days for the region that includes Molokai and Oahu. The NODC C-MAN buoy 51026 temperature record contains hourly data. These data were resampled at a daily frequency after lowpass filtering with an eighth order Chebyshev type I lowpass filter to remove short-term (e.g., tidal period) variations. Data Analysis Statistical testing of growth and developmental data was problematic since different larvae from different cul- ture vessels were measured over the course of the exper- iment (this was done to minimize handling of individual larvae). Therefore, it was necessary to assume that larvae from all culture vessels formed one population. In order to lump data among culture vessels for time series of size and development, it was necessary to test for differences in these parameters among culture vessels. The null hy- pothesis was that the sizes and developmental stages of larvae were not different among culture vessels each day that measurements were conducted. This hypothesis was tested using the non-parametric Kruskal-Wallis test (So- kal & Rohlf, 1969). No significant differences among cul- ture vessels for either size or developmental stage were observed (a = 0.05). Therefore, larval size and devel- opmental stage data were pooled among culture vessels within each day that measurements were conducted. The means and standard deviations for each parameter were then plotted as a function of time. RESULTS Natural Spawning in Mamala Bay A warming event occurred in late August and early September (Figure 2), which may have triggered S. fe- nebrosus in Mamala Bay to spawn sometime between 10 August and 21 September 1996, when adults were col- lected. Water temperatures increased from 24.4° to 26.4°C P. E. Parnell, 2002 Page 61 28 or eee T T T T T ean er Te || Talal T J T T | Us: lies J TraesT T] zl 4 OS) DF aa | | ° apa | a4 =) 26a + < | | S25 3 = | | Broodstock 24 - Sampling =] | Interval | 23 jes (ee tN {1 —4 i nt nen fn STN | eb | ee Bad eae Se eG n Zz MONTH (1996) Figure 2. Temperature data from C-MAN buoy 51026 (17 km north of Molokai). Dotted lines indicate broodstock sampling dates. from early June to 10 August. Temperatures then in- creased at a faster rate from 26.4°C, on 10 August, to a maximum of 28.5°C, on 31 August. Water temperatures decreased after the warming event at a rate similar to the rate of increase prior to the 31 August maximum; the temperature cooled to 26.3°C by 21 September. A second temperature maximum of 28.4°C was observed on 4 Oc- tober. Larval Development and Growth Larvae were not counted during the culture period. However, it is estimated that at least 75% of larvae died within the first 3 days. Antibiotic concentrations were doubled on the fourth day, after which larval mortality appeared to decrease dramatically. It is not clear whether mortality rates decreased due to increased antibiotic con- centrations or decreased larval density. Few mortalities were observed after larvae reached the umbone stage. Mortality rates appeared even lower after larvae reached the pediveliger stage. Larval development stages are plotted as a function of time in Figure 3. Figure 3 is a semi-log plot because the first week of development—during which S. tenebrosus larvae developed through five stages—is emphasized rel- ative to the remaining 7-week culture period—when de- velopment progressed through only two stages. (The time periods below refer to time after fertilization.) First cleav- age occurred within the first hour, and cleavage stages were observed for up to 6 hours. Blastula stages were observed within 4 to 8 hours. Gastrulation was first ob- served at 6 hours (5.0% of larvae), and gastrulae were observed until 17 hours (5.0%). Trochophores first ap- peared within 11 hours (3.3%) and were present in the samples for 40 hours (5.0%). Straight-hinged larvae were first observed in the 21st hour (11.7%), and 8.3% of sam- pled larvae were straight-hinged on day 10. Umbone- stage larvae appeared within 6 days and were observed until 42 days after fertilization (5.0%). Pediveligers first appeared 12 days after fertilization, and more than 100 were still alive when culture was ended on day 60. Figure 4 illustrates sample means and standard devia- tions of larval size (open circles) and developmental stag- es (filled triangles) as a function of time after fertilization. Three larval growth rate periods were observed. The first period included development from the fertilized egg to the trochophore stage when growth was negative. Mean size decreased from 64.3 to 61.9 4m during this period. The second growth period occurred during development from trochophore to the pediveliger stage. The growth rate during this period (11.4 wm day~') was the greatest observed over the time series. The average growth rate of pediveliger larvae, the third larval growth period, de- creased to 1.0 4m day~!, and growth was asymptotic. An asymptote of ~320 wm was calculated from the fit of a cubic regression of size as a function of time. Larval Behavior Larval behavior varied during the culture period. Trochophore through umbone larvae were active swim- mers, and were seldom at the bottom of culture vessels Page 62 dhe Veliger Voly45-)Noral | Pediveliger —- 2a Umbone } 4 Straight-Hinged —- ae fo) = Trochophore —+- 4 Gastrula +- {a = Blastula —- ° 4 First Cleavage 4- oo ’ | Fertilized Egg —2— 43 yf 1 10 100 1000 HOUR Figure 3. Larval developmental stage as a function of time after fertilization. First week of development is easier to visualize on semi- log plot. Larval developmental stages were numerically coded (see Table 1). Time of first observed settlement is indicated. Error bars are one standard deviation of individuals pooled among larval culture vessels. 350 ir So 90° i 300 - 358 gopsontsot ale ABD AA f4Ef 444444444 — Pediveliger A 250 = 4 {i a - Umbone fe) E 200 4jpa - Straight-Hinged N S 150 : - Trochophore - Gastrula 100 - ° - Blastula 50 ° : — First Cleavage o -# | , ) a Fertilized Egg 0 1 2 4 5 6 7 8 WEEK Figure 4. Larval size (open circles) and developmental stage (filled triangles) as a function of time after fertilization. Time of first settlement is indicated. Error bars are one standard deviation of individual larvae pooled among culture vessels. P. E. Parnell, 2002 except when disturbed. In contrast, pediveligers alternat- ed between swimming and crawling on the bottom. Pe- riods between planktonic excursions increased through time. Pediveligers still fed while on the bottom by ori- enting themselves velar-side-up and creating feeding cur- rents with their cilia. The larger pediveligers appeared to sink faster than smaller larvae, and spent most of their time on the bottom of the culture vessels. The feet of these larvae were so large (relative to velum) that they appeared to interfere with swimming. Larval Settlement Pre-soaked adult shell fragments were added to three culture vessels when the first pediveligers were observed (day 12). Settlement was first observed on day 21 (12 December) when 148 spat were counted. The cumulative number of spat increased to 180 by day 23, and decreased to 163 on day 25. Mortality due to handling was the most likely cause of the decrease. The number of settlers fur- ther declined after day 25 in the settlement vessels. Shell fragments were added to the vessels which had never had settlement substrate added on day 58, to de- termine if the pediveligers were still capable of settling. No settlement was observed when larval culture was ter- minated on day 60 even though the larvae appeared healthy, their guts were full of algae, and they were still capable of swimming. DISCUSSION The population of S. tenebrosus on the Waikiki artificial reef spawned between 10 August and 21 September 1996. It is likely that other populations of S. tenebrosus in Ma- mala Bay spawned during this period because the gonads of all the animals sampled from other areas in the Bay on 23 September were empty. Temperature is therefore circumstantially supported as a field spawning cue for S. tenebrosus since warming and spawning occurred within the same 3-week period. Many other pectinaceans have been observed to spawn during summer/fall annual tem- perature maxima (Bonardelli et al., 1996; Tammi & Turn- er, 1997; Villalejo-Fuerte & Garcia-Dominquez, 1998; Baqueiro & Aldana, 2000). The spawning cue that induced adults to spawn in the lab is unclear since the animals were both injected with serotonin, and warmed. Serotonin injections did not in- duce spawning within 2 hours, but the serotonin injec- tions in combination with warming may have triggered spawning. However, warming alone may also have trig- gered spawning. Warming is supported as a spawning cue in the lab because, in this study, natural populations spawned during a warm event, and other pectinaceans spawn in response to warming in the lab (e.g., Monsalvo- Spencer et al., 1997). As a caveat, the results of other lab spawning studies suggest that cold-shock is an effective spawning cue for some tropical pectinaceans (Velez et al., Page 63 1990; Chaitanawisuti & Menasveta, 1992); cold-shock was not attempted in this study. Further work is needed to determine if warming is a consistent spawning cue for S. tenebrosus in the lab and for natural populations. Larval development of S. tenebrosus from fertilization to the straight-hinged stage (first feeding stage) occurs within 24 hours. This rate of development during early stages 1s similar to that reported for other species of trop- ical pectinaceans (Bellolio et al., 1993; Chaitanawisuti & Menasveta, 1992) and faster than some temperate pectin- aceans (Strathmann, 1987). The period that S. tenebrosus takes to develop to the pediveliger stage is shorter (by a few days) than other tropical pectinaceans (Belda & Del Norte, 1988) and up to 2 weeks shorter than temperate pectinaceans (Beaumont & Budd, 1982; Strathmann, 1987). The results of this study suggest that the minimum pre- competent period for larvae of S. tenebrosus, cultured at 22.0° to 24.0°C, is approximately 21 days. The utility of this laboratory-derived period to estimate natural precom- petent periods is arguable, given that temperature and food availability in the field is variable. The precompetent period is likely to decrease with increasing temperature, and increase with decreasing food availability. The sea- sonal range of Oahu surface coastal water is 22.0° to 28.5°C (personal observation), and veligers of S. tenebro- sus occur in the plankton year-round (personal observa- tion). Therefore, in-situ precompetent periods may be less than 21 days during spring, summer, and fall, when the temperature is greater than 24.5°C, and longer during winter when the temperature is lower. It is likely that natural populations of larvae are exposed to lower food concentrations than the larvae cultured in this study. Therefore, the precompetent period of natural larvae may be longer than 21 days any time of year. More than 100 pediveligers that never had substrate added to their vessels survived for the entire 60 day cul- ture period. These pediveligers appeared healthy when culture was discontinued, and probably would have sur- vived longer. The effect of delayed settlement on disper- sion is questionable since older and larger pediveligers appeared to swim for shorter periods with increasing cul- ture period. Events such as periods of large swell may increase the dispersion of long-lived, bottom-dwelling pe- diveligers through resuspension, which would extend the period that these larvae are subject to dispersal. The fact that the larvae that were prevented from settling until day 58 did not immediately settle when substrate was added to their culture vessels suggests that the period that larvae can delay settlement and successfully settle is limited to less than one season. The results of this study indicate that S. tenebrosus is capable of completing its reproductive cycle in the lab within 60 days. Therefore, natural populations of S. fe- nebrosus in Hawaii likely reproduce more than once per year. A 60-day reproductive cycle for pectinaceans is not Page 64 unusual since the reproductive cycle of Argopecten ven- tricosus, a hermaphroditic pectinacean, was observed to be as short as 27 days in the lab (Monsalvo-Spencer et al., 1997). Natural populations of many other pectina- ceans spawn more than once per year (Baquiero & Al- dana, 2000). Acknowledgments. Mike Hadfield provided invaluable advice on larval culture. Craig Smith, Mike Hadfield, and an anonymous reviewer helped improve the manuscript with their comments. The study was supported by the Mamala Bay Study Commission, Honolulu, Hawaii. Temperature data were provided by the Na- tional Oceanographic Data Center. LITERATURE CITED BAILEY-Brock, J. H. 1989. Fouling community development on an artificial reef in Hawaiian waters. Bulletin of Marine Sci- ence 44(2):580-591. BAQUEIRO, E. & D. ALDANA. 2000. A review of reproductive patterns of bivalve mollusks from Mexico. Bulletin of Ma- rine Science 66(1):13—27. BEAUMONT, A. R. & M. D. Bupp. 1982. Delayed growth of the mussel Mytilus edulis and scallop Pecten maximus veligers at low temperatures. Marine Biology 71:97—100. BEeLbA, C. A. & A. G. C. DEL Norte. 1988. Notes on the induced spawning and larval rearing of the Asian Moon Scallop, Amusium pleuronectes (Linne), in the laboratory. Aquacul- ture 72:173-179. BELLOLIO, G., K. LOHRMANN & E. Dupre. 1993. Larval mor- phology of the scallop Argopecten purpuratus as revealed by scanning electron microscopy. The Veliger 36(4):332— 342. BIDWELL, J. P. & S. Spotre. 1985. Artificial Seawater. Jones & Bartlett Publishers: Boston. 334 pp. BONARDELLI, J. C., J. H. HIMMELMAN & K. DRINKWATER. 1996. Relation of spawning of the giant scallop, Placopecten ma- The Veliger, Vol. 45, No. 1 gellanicus, to temperature fluctuations during downwelling events. Marine Biology 124:637-649. CHAITANAWISUTI, N. & P. MENASVETA. 1992. Preliminary studies on breeding and larval rearing of the asian moon scallop Amusium pleuronectes. Journal of Tropical Aquaculture 7: 205-218. Craco, S. M. & D. J. Crisp. 1991. The biology of scallop larvae. Pp. 75-132 in S. E. Shumway, (ed.), Developments in Aqua- culture and Fisheries Science. Elsevier: New York. Kay, E. A. 1979. Hawaiian Marine Shells. Bishop Museum Press: Honolulu. 653 pp. MONSALVO-SPENCER, P., A. N. MAEDA-MARTINEZ & T. REYNOSO- GRANADOS. 1997. Reproductive maturity and spawning in- duction in the catarina scallop Argopecten ventricosus (= circularis) (Sowerby II, 1842). Journal of Shellfish Research 16(1):67—70. RHEE, W. Y. & J. P. Davis. 1997. Larval survival of the rock scallop, Crassadoma gigantea in the hatchery. Journal of Shellfish Research 16(1):348-349. SOKAL, R. R. & EF J. RouwLr. 1969. Biometry. 2nd ed. W. H. Freeman and Company: New York. 859 pp. STRATHMANN, M. F. 1987. Reproduction and Development of Ma- rine Invertebrates of the Northern Pacific Coast. University of Washington Press: Seattle. 670 pp. TAMMI, K. A. & W. H. TURNER. 1997. The influence of temper- ature on spawning and spat collection of the bay scallop, Argopecten irradians in southeastern Massachusetts waters. Journal of Shellfish Research 16(1):349. THORSSON, W. 1987. Things that snap on the cliffs I, Spondylus tenebrosus (Reeve, 1856). Hawaiian Shell News 35(10):14. VELEZ, A., E. ALIFA & O. Azuase. 1990. Induction of spawning by temperature and serotonin in the hermaphroditic tropical scallop, Pecten ziczac. Aquaculture 84:307-313. VILLALEJO-FUERTE, M. & E GARCIA-DOMINQUEZ. 1998. Repro- ductive cycle of Spondylus leucancanthus Broderip, 1833 (Bivalvia: Spondylidae) at Isla Danzante, Gulf of California. Journal of Shellfish Research 17(4):1037—1042. The Veliger 45(1):65—70 (January 2, 2002) THE VELIGER © CMS, Inc., 2002 Mass Exhumation and Deposition of Mulinia lateralis (Bivalvia: Mactridae) on an Intertidal Beach, St. Catherines Island, Georgia, USA CAROL M. CLEVELAND', ROBERT S. PREZANT??, HAROLD B. ROLLINS’, RONALD TOLL*° AND JENNIFER WYLIE? ‘Department of Biology, The University of Mississippi, Oxford, Mississippi 38677, USA; e-mail: bycmc @olemiss.edu *Department of Biology, 114 Weyandt Hall, Indiana University of Pennsylvania, Indiana, Pennsylvania 15705-1090, USA 3Current Address: College of Science and Mathematics, Montclair State University, Upper Montclair, New Jersey 07043, USA; e-mail: Prezant@Mail.Montclair.edu ‘Department of Geology and Planetary Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA; e-mail: Hjroll@cobweb.net Department of Biology, Wesleyan College, 4760 Forsyth Road, Macon, Georgia 31297-4299, USA °Current Address: College of Natural Sciences and Mathematics, University of Central Arkansas, Conway, Arkansas 72035, USA; e-mail: rtoll@mail.uca.edu Abstract. Episodic events which affect populations of marine invertebrate species are rarely documented. We report the catastrophic mass exhumation and deposition of a large aggregation of adult bivalves (Mulinia lateralis [Say, 1822]) to a suboptimal habitat on a sandy intertidal beach of St. Catherines Island, Georgia, USA. The displaced population impacted a large area (7000 m7?) of the beach and consisted of similar-sized clams (~13 mm mean shell length). We suggest that the exhumation could have been a result of storm-induced shear stress, an hypoxic event, or other environ- mental stress on the individuals. Events of this type could have important implications for population dynamics and cohort distribution, fisheries predictions and harvests, and interpretation of fossil assemblages. INTRODUCTION On 4 October 1993 we observed a large patch of Mulinia lateralis (Say, 1822), the dwarf surfclam, in the intertidal zone on South Beach, near Flag Pond, St. Catherines Is- land, Georgia (Figures 1, 2). This was a notable occur- rence because most adult infaunal bivalves are sedentary, moving long distances only as larvae or stochastically by rafting with eroded substrata, and because Mulinia later- alis are normally found subtidally. Mulinia lateralis typically occurs in near-shore envi- ronments along the Atlantic and Gulf coasts of the United States and can be present subtidally in very dense infau- nal aggregations. Mulinia lateralis can occur episodically and in very high densities (21,000 m~’) subtidally (Santos & Simon, 1980). Santos & Simon (1980) found that an ephemeral population of M. lateralis in Tampa Bay, Flor- ida had an average density of approximately 5700 m when present. Montagna et al. (1993) reported a popu- lation in Laguna Madre, Texas with densities up to 800 m? soon after recruitment in the spring, and low densities (< 100 m~) for the majority of the year. Walker & Te- nore (1984) found that the density varied with habitat in Wassaw Sound, Georgia. Populations with the highest av- erage density were in sandy mud (10,161 m~?), whereas mud and sand habitats had lower densities (277 m~? and 263 m~’, respectively), but all population densities fluc- tuated widely. Mulinia lateralis populations have not been reported occurring intertidally in such dense live aggregations as we report, and apparently this aggrega- tion was exhumed and deposited. OBSERVATIONS The site of the Mulinia lateralis accumulation, South Beach, is a medium-energy (silty-sand) beach on the sea- ward side of St. Catherines Island. St. Catherines Island is a relatively pristine environment as there is little human activity on the island except in a research and conserva- tion compound on the north-west (leeward) portion. Mean tidal amplitude is approximately 2.5 m. High tides were increasing toward a maximum, from +2.1 to +2.6 m mean low water at the time of observation, and this con- dition had been present during the 5 days preceding our observations. There had been no significant rainfall since 27 September 1993 when 0.2 cm fell (as recorded on Sapelo Island, Georgia). Wind velocity recorded on Sa- pelo Island had remained below 10 m/sec for the month prior to our observation and reached a velocity of 8.36 m/sec on 30 September 1993. To quantify the extent of the exhumed population in the intertidal zone, we sampled at ebb tide along a tran- Page 66 The Veliger, Vol. 45, No. 1 Georgia Figure 1. Diagrammatic map of St. Catherines Island, Georgia. Salt marsh is indicated by stippling. The study site is indicated by an X. sect extending from the wrack line, approximately 80 m landward of the low tide line, to a tide level present | hour before maximum low tide. We used circular quadrats of 30 cm diameter (area = 706.5 cm*) to sample at 2 meter intervals along the transect. All live and dead clams present to a depth of 7 cm were collected. The number of live and dead clams within each quadrat was counted. Where clams were present on the surface, as well as bur- ied, the ratio of surface to subsurface clams was noted. The exhumed clams covered a large area of the beach (Figure 2). The surface aggregation extended approxi- mately 17 m north to south and 14.5 m east to west (246.5 m’), whereas the sub-surface accumulation was much larger and extended approximately 87 m north to south from the high intertidal into the subtidal zone (7000 m7’). A large, but unquantified, traction load of live and dead clams also was present in the outgoing tidal swash zone. Clams occurred on the surface midway between the swash zone and the wrack line, 24—72 m seaward from the high intertidal zone (Figure 3). Within this zone, the greatest density of exhumed clams occurred between 42 and 52 m from the high intertidal zone. The highest den- sity of live clams occurred at 46 m (23,227 live clams m *; Figure 3). Dead shells were much less abundant, but their distribution paralleled that of the live clams, possi- bly indicating passive transport or post-depositional mor- tality. Live clams composed 78.7% of all shells collected. Between 42 and 52 m from the upper intertidal zone, the surface shells (75%) outnumbered the buried shells (Fig- Figure 2. Mulinia lateralis exposed on South Beach, St. Cath- erines Island, Georgia on 4 October 1993. The infaunal popula- tion extends from high to low tide lines, while the surface clams are aggregated between 42 and 52 meters from the high tide line. Anadara ovalis and Busycon species are also present. Scale bar represents | meter. ure 4), but there were no differences in the proportions of dead and live clams in these samples. The mean length of all clams was 12.84 + 1.17 mm (Figure 5) with no significant (P < 0.001) difference between dead and live clams. The majority of live clams examined were sexu- ally mature with ripe gonads. ACCUMULATION ORIGIN The mass exhumation of Mulinia lateralis reported here was notable because of the limited spatial distribution and because of the very high density of clams involved. Lev- inton (1970) reported large aggregations of dead valves of this species in Long Island Sound and Narragansett Bay, Rhode Island, and discussed the significance of such dense death assemblages for the fossil record. He sug- gested that those assemblages were the result of post- mortem transport. Other bivalves, notably the surf clam Spisula solidissima (Dillwyn, 1817), were observed washed up on New Jersey beaches near their subtidal populations; however, the majority observed during this event were dead or dying (Boyajian & Thayer, 1995). The authors described a storm-deposit of surfclams, and sug- gested mechanisms of exhumation and deposition, in- cluding the hypothesis that storms could remove overly- ing sediment, increasing the likelihood of subsequent population excavation and size-selective excavation and deposition. Rees et al. (1977) also noted storm-induced strandings of several bivalve species along the coast of North Wales. They stated that wave activity could be a factor in the maintenance of soft bottom benthic associ- ations in near-shore waters. Although no storms had occurred along the Georgia coast in the month prior to the exhumation event, large waves remain the likely mechanism transporting these Page 67 C. M. Cleveland et al., 2002 30000 - [o) (o) {2} [o) (o) (o) wo oO N —N Jajaw asenbs Ja 4 BOO nen cnennenenncreeneenceecncrcrennennentcnecntnteeteteetneecnns 0000 BOO fener cece rcnencrnenneneeneee - d swiejd jo Jaquinu 0 AG 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 distance from high tide line (m) (2) ee alive dead es Island, Georgia therin of South Beach, St. Ca Figure 3. Frequency distribution on 4 October 1993. A -~ oe No oh oO PO | | eS nna G ihe is i=l UGE Wo} SpA. oO onc so) S| =| ST 0) Sa et lis ) pay) og > a> euege O.0 m rH 2 G7 oo aH” Ss & ees Zl OLS EG eee 8 g Some Solo Me oy 2 O84 F 0g — 4 oO eee aS) so aH oO 5 Sa Pe apie) a ORO ay) 6S ° Spt Scene aS as Uns g eps ety LC) Fog ES oO os} 2 pie oA oO =) Ti 3S O00 8 o am OH 90 Of 5S ¢ vo . gaach 38 Gao ¢g Be) OF 98S ag wo Sara qa oes eee © mo A S YO ® S.C! © -& aie SIA ses a CoOL G o Lome SO Sats ae SOs a ceegse gS | (=) =) (c) (=| FeO Eo is os yo} = OEE ae oe Gs oe & 3) Bs & Sw E¢R45 Js} 4 as} ©) @ l ga} Sy 3% Gq as es 8° SoH 2 Oo SS CO -S & GY BOOS O Sb) & 6h owH I | SEww oF oO © _, (I ee = oO =} dst je @ (St gS a2 ie) sak and sWe|9d Jo uolodoJd N w 44 distance from high tide line (m) epifaunal alive ie infaunal dead epifaunal dead Ss infaunal alive teralis to surface a la ‘ 4 October 1993. of dead and live Mulinia tribution Island, Georgia, on g 4. Percent con of South Beach, St. Catherines Figure Page 68 1000 number of clams The Veliger, Vol. 45, No. 1 9 95 10 10.5 11 11.5 12 12.5 13 13.5 14 145 15 155 16 16.5 17 17.5 clam length (mm) Figure 5. Georgia, on 4 October 1993. and initiate movement of these fairly large clams. Al- though tidal energy represents a potential source of move- ment of the clams, the tide prior to the exhumation event was not unusual in magnitude. Other mollusks, including the blood ark (Anadara ovalis [Bruguiére, 1789]) and whelk species (Busycon species), which were much larger (5+ cm length) than Mulinia lateralis occurred in patches along the beach on the day of observation, possibly in- dicating community-wide disturbance, rather than a monospecific disturbance. Mulinia lateralis has relatively short siphons that re- quire it to remain near the surface to feed (Chalermwat et al., 1991). Therefore, passing of a shrimp otter trawl net over the population (commercial shrimp trawling is important in Georgia, especially during summer months, and occurs frequently in the ocean waters within sight of St. Catherines Island beaches) could facilitate the exca- vation of large numbers of individuals. Exposure on the sediment surface, combined with the strong tidal flow characteristic of the region or wind-driven mixing, could transport the clams into intertidal areas and deposit them. There were many M. /ateralis still in suspension and bur- ied just beneath the surface in the swash zone (approxi- mately 1400 clams m~°), indicating that the depositional event may still have been occurring, or that the popula- tion was being actively reworked at the time of obser- vation. Bivalves will often move close to or onto the surface when stressed by extremes in environmental conditions, such as low salinity or hypoxic events, possibly enhanc- ing the likelihood of exhumation and transport of a pop- ulation (Cleveland, 1991; Richardson et al., 1993). We have no records of subtidal environmental parameters, Length-frequency distribution of Mulinia lateralis occurring in the intertidal zone of South Beach, St. Catherines Island, such as salinity and temperature, for this area, and there- fore can only speculate as to what caused the observed phenomenon. It seems unlikely that these clams were transported a long distance before being deposited and were probably from an area relatively nearshore in the vicinity of South Beach. Mulinia lateralis typically in- habits sandy-mud substrata (Walker & Tenore, 1984), which are abundant in areas around St. Catherines Island. Most likely, a cojacent population was exhumed and dis- placed. EFFECT on POPULATION DYNAMICS Events similar to the one observed and described could effectively entrain an entire population of clams and move it to a new site. If the exhumation is extensive, the entire population could be deposited onshore, resulting in high mortality by the stress of dislodgment, desiccation, and extreme temperature. Mulinia lateralis is an oppor- tunistic species that colonizes areas quickly (Levinton, 1970), and therefore, exhumation of this type, prior to a major recruitment event, could have short-lived effects on the overall population dynamics. Previous observations of bivalve movement have shown that some large adults, such as the northern qua- hog Mercenaria mercenaria (Linnaeus, 1758), can be en- trained in high energy waters leading to an adjunct mode of dispersal beyond larval propagules (Prezant et al., 1990; Rollins et al., 1992; Boyajian & Thayer, 1995). Also, vagrant bivalves, such as Donax species, move reg- ularly across a habitat (Ansell & Truman, 1973). Passive transport resulting in colonization of a habitat can be an important mechanism for population dispersal and estab- C. M. Cleveland et al., 2002 lishment for opportunistic species (Emerson & Grant, 1991). Hydrodynamic factors are also known to be im- portant in the dispersal of larval bivalves and can result in patchy recruitment events. Bedload transport of juve- nile soft-shell clams Mya arenaria Linnaeus, 1758, can affect population dynamics by immigration of large ag- gregations into underutilized habitats (Emerson & Grant, 1991). The common cockle Cerastoderma edule Linnae- us, 1758, lives in the top few centimeters of sediment, and the combined stressful effects of waves, currents, and burial have been shown to cause the emergence of large numbers of these clams, thereby enhancing the likelihood of their passive entrainment and transport (Richardson et al., 1993). Scallops are notorious for their locomotory ability whereby adults can swim horizontally and migrate to new habitats (Carsen et al., 1995). Juveniles, however, swim vertically and are then advected horizontally by currents and possibly moved into more hospitable habitats (Carsen et al., 1995). The accumulation of Mulinia later- alis described here was composed of adult individuals, providing evidence of the importance of adult dispersal in bivalve population dynamics. IMPLICATIONS Observation and reporting of unexpected ecological phe- nomena such as the one described here can provide valu- able information about population ecology and life his- tory of organisms, as well as information useful for in- terpretation of fossil assemblages (Boyajian & Thayer, 1995). Although population studies and transplantation experiments provide useful information about a species, unrecorded episodic events can produce effects that could subsequently appear in a population and lead to erroneous conclusions regarding range and cohort dynamics. For ex- ample, the size-selective mass exhumation of a portion of a bivalve population could leave a population with the length frequency skewed toward older (or younger) in- dividuals. Future age-class analyses could record this as a low recruitment event, when, in fact, recruitment was normal for the size classes affected by the exhumation. Interpretation of fossil assemblages could be biased by deposition of large numbers of live animals as well as dead shells (Levinton, 1970; Rollins et al., 1992; Aguirre & Farinati, 1999; Walker & Goldstein, 1999). Although we do not have any information on the post-depositional fate of this assemblage, we do know that the sandy in- tertidal beach is not ideal habitat for Mulinia lateralis (Levinton, 1970). Morris & Rollins (1977) described some life-positioned bivalve fossil assemblages on St. Catherines Island. Interpretation of such fossil assem- blages must take into account the history of the assem- blage prior to death as well as that after death (taphono- my). The majority of these M. lateralis were alive, but their condition could have been weakened by the stresses from exhumation, transport, deposition, and desiccation Page 69 in the intertidal zone in such high densities. If this assem- blage remained intact and was buried on the beach, it could be misinterpreted as an in situ population. Alter- natively, the assemblage could be interpreted as a trans- ported death assemblage. Some of the live clams were in life position and could be misinterpreted as having re- cruited to this habitat as juveniles rather than adults (Rol- lins & West, 1997; West et al., 1990). There are many ways that this event could be interpreted that could lead to rational but erroneous conclusions. Documentation of these events can provide useful information about a spe- cies, community or fossil assemblage, and have bearing on shellfisheries’ predictions, yields, and harvests. Acknowledgments. Thanks to Mr. Royce Hayes, Superintendent of St. Catherines Island, for his on-site support and extensive knowledge of the Island. We are grateful for grant support from the St. Catherines Island Foundation, Incorporated, administered by the American Museum of Natural History. We would also like to thank the University of Georgia Marine Institute on Sa- pelo Island for access to climatological data. LITERATURE CITED AGUIRRE, M. L. & E. A. FARINATI. 1999. Taphonomic processes affecting late Quaternary molluscs along the coastal area of Buenos Aires Province (Argentina, Southwestern Atlantic). Palaeogeography, Paleoclimatology, Palaeoecology 149: 283-304. ANSELL, A. D. & E. R. TRUMAN. 1973. The energy cost of mi- gration of the bivalve Donax on tropical sandy beaches. Ma- rine Behavior and Physiology 2:21—32. BOYAJIAN, G. E. & C. W. THAYER. 1995. Clam calamity: a recent supratidal storm-deposit as an analog for fossil shell beds. Palaios 10:484—489. CarsEN, A. E., B. G. HATCHER, R. E. SCHEIBLING, A. W. HEN- NIGAR & L. H. TAyLor. 1995. Effects of site and season on movement frequencies and displacement patterns of juvenile sea scallops Placopecten magellanicus under natural hydro- dynamic conditions in Nova Scotia, Canada. Marine Ecol- ogy Progress Series 128:225—238. CHALERMWAT, K., T. R. JACOBSEN & R. A. Lutz. 1991. Assimi- lation of bacteria by the dwarf surf clam, Mulinia lateralis (Bivalvia, Mactridae). Marine Ecology Progress Series 71: 27-35. CLEVELAND, C. M. 1991. Life history and reproduction in Gon- iocuna dalli (Bivalvia, Crassatellidae). M.S. Thesis. Depart- ment of Biology, University of Southern Mississippi. ix + 130 pp. Denny, M. W. 1988. Biology and the Mechanics of the Wave- Swept Environment. Princeton University Press: Princeton. xii + 329 pp. Emerson, C. W. & J. GRANT. 1991. The control of soft-shell clam (Mya arenaria) recruitment on intertidal sandflats by bed- load sediment transport. Limnology and Oceanography 36: 1288-1300. Levinton, J. S. 1970. The paleoecological significance of op- portunistic species. Lethaia 3:69—78. MontTaana, P. A., D. A. STOCKWELL & R. D. KALKE. 1993. Dwarf surfclam, Mulinia lateralis (Say, 1822) populations and feeding during the Texas brown tide event. Journal of Shell- fish Research 12:433—442. Morris, R. W. & H. B. ROLLINS. 1977. Observations on intertidal Page 70 organism associations of St. Catherines Island, Georgia. I. General description and paleontological implications. Bul- letin of the American Museum of Natural History 159:87— 128. PALMER, M. 1988. Dispersal of marine meiofauna: a review and conceptual model explaining passive transport and active emergence with implications for recruitment. Marine Ecol- ogy Progress Series 48:81—91. PREZANT, R. S., H. B. ROLLINS & R. B. TOLL. 1990. Dispersal of adult hard clams as an adjunct to larval recruitment. Amer- ican Zoologist 30:89A. Rees, E. I. S., A. NICHOLAIDOU & P. LASKARIDOU. 1977. The effects of storms on the dynamics of shallow water benthic associations. Pp. 465—474 in B. F Keegan, P. O. Ceidigh & P. J. S. Boaden (eds.), Biology of Benthic Organisms. Per- gamon Press: New York. RICHARDSON, C. A., I. IBARROLA & R. J. INGHAM. 1993. Emer- gence pattern and spatial distribution of the common cockle Cerastoderma edule. Marine Ecology Progress Series 99: 71-81. Ro.uins, H. B., R. S. PREZANT, R. R. West & R. B. TOLL. 1992. Metapopulation dynamics: potential constraints upon inter- pretation of fossil population structure and taphonomic gra- The Veliger, Vol. 45, No. 1 dients. 27th Annual Meeting of the Geological Society of America, Northeast Sector 24(3):71. Ro tiins, H. B. & R. R. West. 1997. Taphonomic constraints on event horizons: Short-term time averaging of Anadara bras- iliana valves, St. Catherines Island, Georgia. Pp. 41—56 in C. E. Brett, & G. C. Baird (eds.), Paleontological Events. Columbia Press. Santos, S. L. & J. L. Simon. 1980. Response of soft-bottom benthos to annual catastrophic disturbance in a south Florida estuary. Marine Ecology Progress Series 3:347—355. WALKER, R. L. & K. R. TENORE. 1984. Growth and production of the dwarf surf clam Mulinia lateralis (Say 1822) in a Georgia estuary. Gulf Research Reports 7:357—364. WALKER, S. E. & S. T. GOLDSTEIN. 1999. Taphonomic tiering: experimental field taphonomy of molluscs and foraminifera above and below the sediment-water interface. Palaeogeog- raphy, Paleoclimatology, Palaeoecology 149:227—244. WEsT, R. R., H. B. ROLLINS & R. M. Buscu. 1990. Taphonomy and an intertidal palimpsest surface: Implications for the fos- sil record. Pp. 351—369 in W. Miller III (ed.), Paleocom- munity Temporal Dynamics: The Long-Term Development of Multispecies Assemblies. Paleontological Society Special Publication No. 5, University of Tennessee, Knoxville. The Veliger 45(1):71—78 (January 2, 2002) THE VELIGER © CMS, Inc., 2002 The Natural Diet of the Argentinean Endemic Snail Chilina parchappii (Basommatophora: Chilinidae) and Two Other Coexisting Pulmonate Gastropods A. L. ESTEBENET*, N. J. CAZZANIGA AnD N. V. PIZANI Universidad Nacional del Sur, Departamento de Biologia, Bioquimica y Farmacia, 8000 Bahia Blanca, Argentina Abstract. In this paper we study the natural diet of Chilina parchappii (d’Orbigny) (Chilinidae), Biomphalaria peregrina (d’Orbigny) (Planorbidae), and Physa venustula Gould (Physidae) in an artificial canal in the Province of Buenos Aires, Argentina. The close similarity between the organic particle composition of the sediment and the crop contents of the three species studied suggests they are basically non-selective feeders. The food composition does not differ from the Aufwuchs composition. Diatoms and detritus particles are the main food items for the three species. Although there is a high degree of diet overlap among the three species, a principal component analysis revealed interspecific differences in diet. Biomphalaria peregrina is more detritivorous; Chilina parchappii ingests more diatoms; and Physa venustula consumes more non-filamentous algae. Experimental analysis of the ingestion, egestion, and assim- ilation rates, and the assimilation efficiency suggests that the endemic Chilina parchappii is subject to a probable risk of competition in a case of food shortage. However, competition among snails is highly improbable in the present area of sympatry, i.e., the lower basin of the Naposta Grande stream, which is rich in detritus. INTRODUCTION Periphyton and detritus particles are almost universal food items for freshwater gastropods. Although some se- lection against or for specific items can be found, pul- monates are predominantly non-selective feeders (Hunter, 1980; Madsen, 1992; Brendelberger, 1995, 1997). Selective grazing by freshwater gastropods has, how- ever, been proposed as a cause of shifts in the succession of the benthic algae (Tuchman & Stevenson, 1991) or changes in periphyton composition (McCollum et al., 1998). Whereas detritus was by far the most common item in the gut of 20 snail species in England (Reavell, 1980), Planorbis vortex (Linnaeus) specifically selected against detritus and for diatoms (Lodge, 1986). Ancylus fluviatilis (Miiller) also preferred diatoms and other peri- phytic algae, and did not eat detritus or fungal hyphae (Calow, 1973a, b). Trophic strategies are therefore vari- able among the freshwater snails, according to environ- mental and functional conditions. The most abundant species of pulmonate snail in the lower basin of the Naposta Grande stream (Buenos Aires Province, Argentina) are the recently introduced Physa venustula Gould, 1847 (Physidae), the native Chilina par- chappii (d’Orbigny, 1835) (Chilinidae), and Biomphal- aria peregrina (d’Orbigny, 1835) (Planorbidae). The natural diets of these three South American species have not been studied previously. Some extrapolations are possible from the literature showing that the Planorbidae * e-mail: estebene @criba.edu.ar and Physidae show great ecological uniformity (Calow, 1973b; Hunter, 1980; Reavell, 1980; Kesler et al., 1986; Underwood & Thomas, 1990; Madsen, 1992; Carman & Guckert, 1994), but nothing is known at present about the feeding habits of the South American endemic family Chilinidae. Species of Chilinidae have been deemed to feed only on diatoms (Brace, 1983; Bosnia et al., 1990). In this paper we study the natural diet of Chilina par- chappii, Biomphalaria peregrina, and Physa venustula with the aim of determining whether they feed non-se- lectively and whether the diet of the invading species (P. venustula) overlaps those of the native species (B. pere- grina and C. parchappii). MATERIALS AnD METHODS The sampling site is an artificial canal within Parque de Mayo, an urban park in Bahia Blanca city (38°44’S— 62°00’W, Argentina). It is fed with water from the Na- posta Grande stream. The selected portion of the canal is 70 m long and about 4 m wide, with a maximum depth of 0.60 m. The sediment is mostly sandy silt, with a high proportion of detritus. The macrophytes Myriophyllum elatinoides (L.), Potamogeton striatus Ruiz & Pavon, and Chara contraria A. Braun ex Ktitz, form dense mats in the center of the canal during most of the year. The bio- mass of the former two species decreases dramatically in winter. Sampling was performed on six dates from December 1992 to November 1993. Individuals of the three snail species were picked up by hand along the canal margins, Page 72 The Veliger, Vol. 45, No. 1 and immediately killed by immersion in hot water. The soft parts of the snails were extracted in the laboratory and frozen at —20°C for further analysis. Freezing was the best procedure to preserve the ingested algae, as re- vealed by preliminary trials of different preservation techniques (alcohol, formaldehyde, FAA, freezing); the alterations produced by chemicals made it difficult to rec- ognize food items. In winter (July), only individuals of Chilina parchappii were found in the canal, and their digestive tracts were empty, except for a small quantity of mineral particles retained in the stomachs. This sampling season was there- fore excluded from the comparative analysis. To detect possible ontogenetic differences in the diet we defined two disjunct size classes for each species, as follows: Biomphalaria peregrina (maximum diameter), young < 7 mm, adult > 13 mm; Chilina parchappii (shell length), young < 7 mm, adult > 17 mm; Physa venustula (shell length), young < 5 mm, adult > 8.7 mm. The natural diets were analyzed by spreading the con- tents of the rear portion of the esophagus or crop in a drop of distilled water, prior to their observation under a compound microscope at a magnification of 400. We examined four to 14 snails for each species and date. The algae were identified to the generic or specific level, but were grouped into six groups for quantitative analyses: blue-green algae (BG), diatoms (Di), filamentous green algae (F), non-filamentous algae (unicellular, paucicellu- lar, or colonial) (NF), detritus (De), and sand (S). The presence of these six items was recorded on 20 randomly selected microscope fields per individual. The volume of the crop contents varied among and within the snail species as a consequence of body size and the degree of gut fullness. Therefore, for each indi- vidual snail, we determined the proportion of microscope fields where each kind of food was recorded in relation to the sum of all the fields with positive records: Pi = iy Dy nj where p; is the relative proportion of fields with food i, and n; is the number of fields containing the food i (Kesler et al., 1986). On the first sampling date we took simultaneous sam- ples of sediment and periphyton to investigate possible selective feeding by comparing them with crop contents. The samples were taken from three different sites by scraping or sucking with a pipette the surface where the snails were adhering to the substrate. The crop contents of 154 dissected snails were ana- lyzed by principal components (PCA), using the covari- ance matrix as input (Orl6ci & Kenkel, 1985), to deter- mine possible seasonal and specific variations in the snail diets. Laboratory experiments were performed to quantify the ingestion rate, egestion rate, and assimilation efficien- cy of the three snail species. Only adult snails were used in these trials. Forty-eight previously weighed glass slides (75 X 25 X 1.2 mm) were placed in a periphyton sam- pling box, and immersed in an artificial shallow pond. Three weeks later, when a substantial growth of Aufwuchs was evident, the slides were transferred to the laboratory and washed with demineralized tap water to remove loose material. Algae attached to the slides were mainly dia- toms (mostly Navicula spp.) and the disk-shaped green Coleochaete sp. For every gastropod species, nine groups of three snails each (previously starved for 24 hr) were placed in Petri dishes 95 mm in diameter, filled with 50 ml of demineralized tap water. Six groups received two colonized slides as food; the remaining three groups were used as controls (without food). Twelve colonized slides were immersed in similar Petri dishes, without snails, as a reference of non-predated periphyton biomass. Snails were allowed to feed for 4 hours before slides were removed, washed, dried at 60°C for 48 hr, and weighed to the nearest 0.1 mg. During the feeding tests, the feces produced by the snails (feeders and control) were collected with a Pasteur pipette. After removal of the slides, fecal collection was continued for an additional 4 hours. The snails were then killed by immersion in hot water and their soft parts were extracted from the shells. Feces and soft parts were dried at 60°C for 48 hr, and weighed to the nearest 0.1 mg. To quantify ingestion, egestion, and assimilation rates we used the following formulae: Ingestion rate IR = TI/DW Egestion rate ER = TF/DW Assimilation rate AR = IR — ER Assimilation efficiency AE = (TI — TEF)-100/TI Total ingestion (TI) represents the total amount of food ingested (in mg), and is calculated as the difference be- tween the dry periphyton weight on the non-predated and predated slides after the feeding period. Total feces (TF) represents fecal production (in mg); it was corrected by subtracting feces produced by control snails. DW is snail dry weight (in mg). Mean values of IR, ER, AR, and AE of the three species were compared by one-way ANOVA on the transformed data (log transformation for the rates; arcsine square root for the efficiency). The a posteriori multiple comparisons were made by Scheffé tests. RESULTS Although the basic morphology of the digestive system is the same in the three species, there are some differ- ences in the strength and degree of differentiation of the stomach region. Chilina parchappii shows a striking con- trast between the relatively broad, almost black crop opening to a strongly muscular, bulbous, pearl pink giz- zard. The crop is also well differentiated in Biomphalaria peregrina, but the gizzard is less muscular. The stomach A. L. Estebenet et al., 2002 of Physa is morphologically simpler, uniformly grey col- ored, with no clear differentiation between crop and giz- zard, the latter being thin-walled. Figure 1 shows the temporal variation of the whole crop contents of the three species. No ontogenetic differ- ences were detected for any snail species with respect to trophic preference (test t, P > 0.05 in all cases). Because of this, data from young and adult snails were grouped for the rest of the analysis. All snail crops contained some mineral particles (sand) that probably aid in grinding the food (mainly the diatom frustules). The proportion of mineral particles was, how- ever, significantly different among the snail species (F = 16.82; df = 2, 152; P < 0.0001). An a posteriori Scheffe’s test showed that Biomphalaria peregrina was the species with the highest proportion of ingested sand, whereas no significant difference in sand content was de- tected between Physa venustula and Chilina parchappit. The main food particles were detritus and diatoms in the three species. The most frequent diatoms were in the genera Achnanthes, Cocconeis, Epithemia, Fragilaria, Gomphonema, Gyrosygma, Navicula, Nitzschia, Rhoicos- phenia, Surirella, and Synedra; with a lesser frequency we recorded the diatoms Asterionella, Amphora, Cym- bella, Diatoma, and Pinnularia. The filamentous green algae were represented by Cladophora spp. and Oedo- gonium spp. The non-filamentous algae were Scenedes- mus (constant in all dissected esophagi), Ancystrodesmus, Coelastrum, Crucigenia, Oocystis, Pediastrum, Tetrae- dron, and Euglena. The blue-green algae were always represented by Chroococcus and Merismopedia, but the filamentous Anabaena and Oscillatoria were also present in a lesser proportion. We found fragments of macrophyte leaves (specifically Potamogeton striatus) in only two (1.3%) of the 154 an- alyzed crops. While radular teeth were seldom found in the crop con- tents of Biomphalaria and Physa (4.9% and 5.7% of the crops, respectively), 46% of the stomachs of Chilina par- chappii contained radular teeth, mainly marginal teeth with highly eroded cusps. We also recorded occasional animal remains, mostly chaetae of oligochaetes, some statoblasts of Plumatella sp. (Phylactolaemata), shells of newly hatched Heleobia parchappii (d’ Orbigny) (Gastropoda: Hydrobiidae), frag- mented rotifers, and microcrustacean appendages. Figure 2 shows the relative abundance of the different food categories in the digestive tube of Biomphalaria, Chilina, and Physa (irrespective of the body size) as com- pared with the organic particles in the substrate samples from late spring. The composition of the crop contents in the three species showed a great similarity to the substrate composition. The only significant differences were due to a higher proportion of non-filamentous algae in the crops of B. peregrina and P. venustula (t = 3.68, df = 23, P Page 73 < 0.001, and t = 4.86, df = 21, P < 0.0001, respec- tively). The results of PCA performed on the diets (sand ex- cluded) are shown in Table | and Figure 3. The first com- ponent was highly positively correlated with the relative abundance of Di, and highly negatively correlated with NE Snails whose diet included more Di relative to NF scored highly on this component. The second principal component was highly positively correlated with Di and highly negatively correlated with De. Stomachs with high content of Di relative to De scored highly on this com- ponent. There was a high degree of diet overlap among the three species, but PCA still revealed interspecific varia- tions. The mean principal component scores of the three groups differed significantly for PCl and PC2 (one-way ANOVA test, Table 1). The multiple comparison (Scheffé test) revealed that Biomphalaria peregrina is more detri- tivorous, Chilina parchappii ingests more diatoms, and Physa venustula ingests more non-filamentous algae. Some seasonal variations in the abundance of the dif- ferent items could be detected (Figure 3). The isolated position of the autumn (April) samples of Physa venus- tula was mostly due to the high content of non-filamen- tous algae, represented in this case by Euglena spp., a kind of organism that never appeared in the other snail species or on other sampling dates. In the laboratory experiments, Physa venustula showed the highest rates of ingestion and egestion (P < 0.05), whereas Biomphalaria peregrina always had the second highest position (Figure 4). The values for Chilina par- chappii were extremely low as an outcome of its peculiar behavior. Physa and Biomphalaria remained on the col- onized artificial substrates most of the time during the feeding experiment, and browsed actively on the slides with the radula. Chilina instead crawled around and across the Petri dishes, with few buccal movements, even when they passed over the slides, leaving a large amount of mucus on the substrata. Assimilation efficiencies ranged from 34% to 82%, with the lowest mean value achieved by Physa venustula. DISCUSSION Many authors have shown that freshwater pulmonate snails are non-selective, microphagous animals. In this category are included, for example, several species in the genera Lymnaea, Helisoma, Biomphalaria, and Bulinus (Calow, 1970; Hunter, 1980; Baluku et al., 1987; Smith, 1989; Adam & Lewis, 1992; Madsen, 1992). The differ- ences in the diet of snails living in different water bodies mainly reflect the variation in the composition of the Auf- wuchs. Dillon & Davis (1991) even proposed using snail stomach contents as samples of the local diatom assem- blages. The close similarity between the organic particle com- Page 74 The Veliger, Vol. 45, No. 1 Late spring OST eo 1 O25 = para Olas SS € 06 Cadults | | 06 - | 06 - SZ 05 | Myoung | | o5 4 0.5- Fa 0.4- | 04; 4 0.4-— o O03 19 nOFS ia | 0.3 5 = 02 In] | G24 li | ely ! | 6 014 1} | o1 L | 0.1 y o 0+ i mu ie z| oe Un 4 \ oo ee 0- 4 1 i _ Midsummer OO a aa 0.7 7 a OF = SS = 0:67 06 | 0.6 | 2 055 0.5 | 0.5 | B 04: | | 04 } 04) yy | ® 0.37, | 03 4 | 0.3 3 5S 2 |] 0s 5] elie a] 7 @ 01+ 3 ee | OI OT th ee Midautumn MRM perme rany Oa —___-- Oe y= a —— & 064 0.6 | | 0.6 4 057 0.5 O85 | B 0A | | 04+ | 04 4 3 | ay OR | 0.3 5 | OZ 4 | Z 02 i] 0.2— ; 0.2 nil | w Ss | a { A =f sin | a | + | im | nin | oA al) Li Ab [feta | tee | Early spring 9 07 = = 0.7 5 = SSS OF FS — —— = 06; 0.6 | 0.6 - OSs 0.5 | | 0.5 | B 0.4 - ) | 044 ea | 044 § | o 03 4 (Pa 0.3 4 0.3 4 | Z 02 | | | | 024 | i 0.2 - ; | @ 01; l | Os 10:4 | w 0 | 1a Om, je 0 | {1am Ca, aj On= tl pie es Midspring Di Oat eee Se = ea ota a a —— = 06 0.6 - | | Bey | 2 054 | 05 4 | 0 B 0A 0:42) | ane (ob) 0.3 0.3 | 0.2 ly | 02 | an SN Ms a | oI De Di S NF BG F De Di S NF BG F De Di S NF BG F Biomphalaria peregrina Chilina parchappii Physa venustula Figure 1. Crop content (mean + SE) of Biomphalaria peregrina, Physa venustula, and Chilina parchappii from an artificial canal in Buenos Aires province. De, detritus; Di, diatoms; S, sand; NE non-filamentous algae; BG, blue-green algae; E filamentous green algae. A. L. Estebenet et al., 2002 Page 75 0.6 le ‘De OD ANF BG MF 2) oO il RK] xX SK Or > 28 ~? oO IN +: o, OxoO> ee 5 és ee © io) | x> 05 oe 8 te, SM x os relative abundance SERS x nae Cee | a ren a a © NO aos SBBSSS 552505 5SUaa5 Sennen io) = x x> 2 Ho an 7 ? “ He a a ox <9 |_| w x | = [LTT Tt Tit yt tT) xx R980 | a ES O 4 Pas B. peregrina C. parchappii Pore od oS *] >I x ca > en 7 <> So re SS en gS a5 eres J ese xX SO en oe os oe Fe > oS SOS SSK a? ee eee CAS aren 7 eS ne BRS S55 BON SK re} = CTT S54 BS HH we ese] = LL eee od) ela races se) AL ress ese} LL rere see) Koes ps] EH ieee | ses) ALT rate | bse YT yy Ke ese] HL pene ses} LHL SeSe4 106.4 aaa ke ses) CC Seq KA corn Dox) 2 -_—— + P. venustula Substratum Figure 2. Crop content (mean + SE) of Biomphalaria peregrina, Physa venustula, and Chilina parchappii and the relative abundance of organic particles in the substrate samples from late spring. Abbreviations as in Figure 1. position of the sediment and the crop contents of the three species studied suggests that they are basically non-se- lective feeders. When these animals feed on the same substrate, their diets are similar, and the diet composition does not differ from the Aufwuchs composition. The dif- ferences found among our snails are most probably due to the microdistribution of the patches of periphyton, re- sulting in a wide intraspecific variability. Nevertheless, Biomphalaria peregrina exhibited a stronger tendency to eat more detritus than Chilina and Physa. This is consistent with the microdistributional in- formation by Martin (1999) who stated that B. peregrina reaches its maximum abundance in the middle basin of the Naposta Grande stream, and that detritus affects its distribution. The middle basin receives organic contami- nation from a wide agricultural area, and effluent from the city. This portion of the stream was considered as mesosaprobic (Cazzaniga & Curino, 1987; Pettigrosso & Cazzaniga, 1987). The lack of ontogenetic differences in the diet of the three species studied here is consistent with previous re- ports on Biomphalaria pfeifferi, Helisoma duryi, Bulinus truncatus, and Bulinus forskalii (Baluku et al., 1987; Madsen, 1992). Many freshwater pulmonates carry sand particles in their stomachs as a means of food grinding (Storey, 1970; Calow, 1973a; Reavell, 1980). Underwood & Thomas (1990) suggested that these mineral particles should also be a source of ions, micronutrients, and microorganisms. Lymnaea peregra shows low growth rates if its diet is devoid of mineral particles (Storey, 1970). Biomphalaria glabrata (Say) actively swallows sand and is able to se- lect the size of the particles it retains in its digestive tube (Schmolder & Becker, 1990). Reavell (1980) found a very low proportion (and even absence) of sand grains in the diet of Physa gyrina (Say), indicating that the diam- eter of the mouth was a physical barrier to its ingestion. This does not seem to be the case in P. vernalis Taylor & Jokinen, where the sand grains can compose up to 15% of the diet (Kesler et al., 1986), or in P. venustula from the Naposta Grande stream (19%). Blue-green and filamentous green algae are not impor- tant items in the diet of Biomphalaria, Chilina, and Physa in the studied area, as revealed by the low proportion of these items in their crops throughout the year. Other pul- monate species seem to prefer filamentous green algae (Lodge, 1986). Madsen (1992) determined that Biom- phalaria pfeifferi, Bulinus truncatus, and Lymnaea natal- ensis are able to select against blue-green algae. The tox- icity of some blue-green algae and their mucopolysac- Page 76 Biomphalaria peregrina 0.6 5 = | | 4 Late spring Midsummer 0.4 ‘| | @ Midautumn | © Early spring 0.2 ~ .@ Midspring N | = aa a ” 4 r taal “aa Be | A ASR Bo8 -0.2 7 a ® 4 A 04 | “e -0.6 T T T T IG ah T Th T T T 08 06 04 -02 0 0.2 0.4 axis 1 Chilina parchappii 0.6 5 = 0.4 - = 7 G 0.2 5 348 ay me N 7 &g ro Pishek | 20 | a ey Sse {4 Al $ & ©6 -0.2 1 i | eo 0.4 5 ~ 06 + ao 08 O06 04 -02 0 0.2 0.4 axis 1 Physa venustula 0.6 5 ; 0.4 - " | a 0.2 ail ap ar B g nN 8 ay te a 4 x 07 yor = & 8 -0.2 + $ 4, e°B 0.4 - | | ® | <0) 6 se 08 O06 04 02 0 0.2 0.4 axis 1 Figure 3. Crop content variations of Biomphalaria peregrina, Physa venustula, and Chilina parchappii based on the first and second principal component scores. The Veliger, Vol. 45, No. 1 Table | Eigenvalues and component loadings for the first two principal components for Chilina parchappii, Biomphal- aria peregrina, and Physa venustula based on crop contents. PC1 PC2 loadings loadings Diatoms (Di) 0.6332 0.7093 Non-filamentous algae (NF) —0.9230 0.3015 Filamentous green algae (F) 0.0758 0.1232 Blue-green algae (BG) 0.0519 0.1865 Detritus (De) 0.3187 —0.8278 Eigenvalues 0.0297 0.0232 ZJovariance explained 48.82 38.16 F-Value* 14.39 7.16 jz 0.00001 0.0011 * From ANOVA of the three species means of the principal component scores. charide sheet should account for their low palatability. Some pulmonate species, however, have been successful- ly reared under laboratory conditions on a diet of blue- green algae (Skoog, 1978; Itagaki, 1987). It is probable that the low concentration of these algae in the stomachs of all of our snails was due simply to their low density in the substrate. Diatoms eaten by Biomphalaria, Chilina, and Physa showed a variety of forms, sizes, and habits. Underwood & Thomas (1990) pointed out that certain anatomic traits or growing forms of algae can reduce the probability of being swallowed by different species of invertebrates. Hunter (1980) stated that Cocconeis is able to escape snail predation as an outcome of its morphology. Nev- ertheless, Smith (1989) and Dillon & Davis (1991) pro- posed that snails sample the diatom flora almost random- ly, with only a few larger species under-represented in the gut contents. In this study we recorded a diversity of diatoms, from the small ovoid Cocconeis, to the elongat- ed and narrow forms of Synedra, or the robust Amphora. There exists, however, a dominance of mobile diatoms (Navicula, Nitzschia, Fragilaria) and those living at- tached to the substrate by mucilaginous peduncles (Cym- bella, Rhoicosphenia, Gomphonema). Due to their low level of adherence, these diatoms appear to be more vul- nerable to attack by snails. Biomphalaria peregrina, Chilina parchappii, and Phy- sa venustula do not eat macrophytes. The scarcity of mac- rophyte fragments in their diet is consistent with other reports in the literature (Br6nmark, 1990; Underwood & Thomas, 1990; Madsen, 1992). Leaf hardness seems to be one of the main reasons why pulmonates refuse to eat aquatic plants. The loss of a significant number of radular teeth has been correlated with the consumption of mac- rophyte material, and the use of macrophytes as food has A. L. Estebenet et al., 2002 Page 77 1:005- 90 F | = Physa venustula ao I | Biomphalaria peregrina | a | b& ® Chilina parchappii 7 io eS 0.10 -- E a +60 3 5 E a 5 oe r + 50 E 2 [ ® = i 40 ¢ = | = 0.01 + Ee SOn ae E c € c b 20) L 14) Fr ae hO 0 ingestion egestion assimilation assimilation rate rate rate efficiency Figure 4. Ingestion rate, egestion rate, assimilation rate, and assimilation efficiencies (mean + SE) of Biomphalaria peregrina, Physa venustula, and Chilina parchappii fed on artificial substrates. Columns sharing the same lower-case letter are not significantly different from each other. been thought to be energetically disadvantageous (Ced- eno-Leé6n & Thomas, 1982; Thomas, 1982). Mackenstedt & Markel (1987) determined that the replacement of teeth in some freshwater gastropods is a continuous process and that Lymnaea, for example, replaces a whole radula in 24 days. Although aquatic plants do not constitute a food item for Chilina, almost half of the specimens swal- lowed their own radular teeth. The presence of teeth in the stomachs of Chilina corresponds therefore to this nat- ural replacement process, and is not a consequence of food hardness. Ingestion rates calculated for Chilina parchappii were much lower than the rates for the other two species. Since the algae colonizing the slides were those normally eaten in the same proportion as they appear on the substrate, this difference was probably due to ethological factors. The assimilation values found in this study fit within the range already published for other pulmonate species (reviewed by Brendelberger, 1997). The strength of the crop differs from the slender crop of Physa to the strong, muscular one of Chilina, possibly accounting for ob- served differences in efficiency rates. Biomphalaria and Chilina better fit the primitive model of stomach-grinders (Brace, 1983). The highest assimilation efficiency was shown by Biomphalaria, which is the species with the highest proportion of sand in the crop. Physa, the species with the highest ingestion rate, has the weakest stomach and the lowest efficiency. Chilina, with its strong grinding stomach, compensates for its low ingestion rate and reaches a high assimilation efficiency. Chilina parchappii, endemic and less active than the other species, is subject to a probable risk of competition in a case of food shortage. The potential for food limi- tation in lotic ecosystems is small, but there is evidence (mostly indirect) suggesting that inadequate food supplies can limit some stream invertebrate populations (Crowl & Schnell, 1990; Hill, 1992). Competition among snails is highly improbable in the present area of sympatry, 1.e., the lower basin of the Na- posta Grande stream, which is rich in detritus, but it may occur if the invader Physa reaches the oligosaprobic sec- tor of the stream where Chilina parchappii is the domi- nant species. In recent years, Physa has advanced some 50 km upstream (Martin, 1999). Acknowledgments. Sincere thanks are due to Patricia Leonardi for her help in the taxonomic recognition of the algae, and to Pablo Martin for his cooperation in the field work. A.L.E. and N.J.C. are members of the Scientific Research Career of CONI- CET (‘Consejo Nacional de Investigaciones Cientificas y Téc- nicas’’) and C.I.C. (“‘Comision de Investigaciones Cientificas de la Provincia de Buenos Aires’’), respectively. This paper was partially funded by ‘“‘Universidad Nacional del Sur” and C.I.C. LITERATURE CITED ApaM, M. E. & J. W. Lewis. 1992. The lack of co-existence between Lymnaea peregra and Lymnaea auricularia (Gas- Page 78 tropoda: Pulmonata). Journal of Molluscan Studies 58:227— 231 BALUKU B.. G. JoSENS & M. LorREAu. 1987. Le regime alimen- taire de Biomphalaria pfeifferi (Gastropoda: Planorbidae) au Zaire Oriental. Revue de Zoologie Africaine 101:279—282. Bosnia A. S., FE J. Katstin & A. TABLADO. 1990. Population dy- namics and production of the freshwater snail Chilina gib- bosa Sowerby 1841 (Chilinidae, Pulmonata) in a North-Pa- tagonian reservoir. Hydrobiologia 190:97—110. Brace, R. C. 1983. Observations on the morphology and behay- iour of Chilina fluctuosa Gray (Chilinidae), with a discus- sion on the early evolution of pulmonate gastropods. Phil- osophical Transactions of the Royal Society of London, B 300:463-—491. BRENDELBERGER, H. 1995. Dietary preference of three freshwater gastropods for eight natural foods of different energetic con- tent. Malacologia 36:147—-153. BRENDELBERGER, H. 1997. Contrasting feeding strategies of two freshwater gastropods, Radix peregra (Lymnaeidae) and Bi- thynia tentaculata (Bithyniidae). Archiv fiir Hydrobiologie 140:11-21. BRONMARK, C. 1990. How do herbivorous freshwater snails affect macrophytes?—A comment. Ecology 71:1212—1215. Catow, P. 1970. Studies on the natural diet of Lymnaea peregra obtusa and its possible ecological implications. Proceedings of the Malacological Society of London 39:203-215. CaLow, P. 1973a. The food of Ancylus fluviatilis, a littoral stone dwelling herbivore. Oecologia 13:113—133. Ca_ow, P. 1973b. Field observations and laboratory experiments on the general food requirements of two species of fresh- water snails, Planorbis contortus and Ancylus fluviatilis. Proceedings of the Malacological Society of London 40: 483-489. CARMAN, K. R. & J. B. GUCKERT. 1994. Radiotracer determina- tion of ingestion and assimilation of periphytic algae, bac- teria, and adsorbed amino acids by snails. Journal of the North American Benthological Society 13:80—88. Cazzanica, N. J. & A. C. Curino. 1987. On Dugesia anceps (Kenk, 1930) (Turbellaria Tricladida) from Argentina. Bol- lettino di Zoologia 54:141—146. CEDENO-LEON, A. & J. D. THoMas. 1982. Competition between Biomphalaria glabrata (Say) and Marisa cornuarietis (L.): feeding niches. Journal of Applied Ecology 19:707—721. Crow, T. A. & G. D. SCHNELL. 1990. Factors determining pop- ulation density and size distribution of a freshwater snail in streams: effects of spatial scale. Oikos 59:359-367. Ditton, R. T., JR. & K. B. Davis. 1991. The diatoms ingested by freshwater snails: temporal. spatial, and interspecific var- iation. Hydrobiologia 210:233—242. HLL, W. R. 1992. Food limitation and interspecific competition in snail-dominated streams. Canadian Journal of Fisheries and Aquatic Sciences 49:1257—1267. Hunter, R. D. 1980. Effects of grazing on the quantity and qual- ity of freshwater aufwuchs. Hydrobiologia 69:251—259. The Veliger, Vol. 45, No. 1 ITAGAKI, T. 1987. Influence of food on the growth and fecundity of Lymnaea ollula, the intermediate host of the liver fluke. The Japanese Journal of Parasitology 36:30—35. KesLeR, D. H., E. H. JOKINEN & W. R. Munns. 1986. Trophic preference and feeding morphology of two pulmonate snail species from a small New England pond. Canadian Journal of Zoology 64:2570—2575. Lopce, D. M. 1986. Selective grazing on periphyton: a deter- minant of freshwater gastropod microdistribution. Freshwa- ter Biology 16:831-841. MACKENSTEDT, U. & K. MARKEL. 1987. Experimental and com- parative morphology of radula renewal in pulmonates (Mol- lusca, Gastropoda). Zoomorphology 107:209—239. MapDsEN, H. 1992. Food selection by freshwater snails in the Gezira irrigation canals, Sudan. Hydrobiologia 228:203— QT: McCoLium, E. W., L. B. CROWDER & A. McCoLium. 1998. Complex interactions of fish, snails, and littoral zone pe- riphyton. Ecology 79:1980—1994. Martin, P. R. 1999. Estudios ecolégicos sobre los gaster6podos del arroyo Naposta Grande. Doctoral Dissertation. Univer- sidad Nacional del Sur, Bahia Blanca (Argentina). 274 pp. Orvoci, L. & N. C. KENKEL. 1985. Introduction to Data Analysis. International Co-operative Publishing House: Fairland, Maryland, USA. 405 pp. PeTTIGROSSO, R. E. & N. J. CAZZANIGA. 1987. Registro de tres especies de Aspidisca (Ciliata, Hypotrichida) en la Argen- tina. Anales del Museo de Historia Natural de Valparaiso, Chile 18:5—12. REAVELL, P. E. 1980. A study of the diets of some British fresh- water gastropods. Journal of Conchology 30:253-271. SCHMOLDER, U. & W. BECKER. 1990. Uptake of mineral particles by Biomphalaria glabrata (Say) (Pulmonata, Mollusca) and its importance for growth rate and egg production. Interna- tionale Revue des gesamten Hydrobiologie 75:95-101. SKooc, G. 1978. Influence of natural food items on growth and egg production in brackish water populations of Lymnaea peregra and Theodoxus fluviatilis (Mollusca). Oikos 31: 340-348. SmiTH, D. A. 1989. Test of feeding selectivity in Helisoma tri- volvis (Gastropoda: Pulmonata). Transactions of the Ameri- can Microscopical Society 108:394—402. Storey, R. 1970. The importance of mineral particles in the diet of Limnaea pereger (Muller). Journal of Conchology 27: 191-195. Tuomas, J. D. 1982. Chemical ecology of the snail hosts of schis- tosomiasis: snail-snail and snail-plant interactions. Malacol- ogia 22:81-91. TUCHMAN, N. C. & R. J. STEVENSON. 1991. Effects of selective grazing by snails on benthic algal succession. Journal of the North American Benthological Society 10:430—443. UNDERWOOD, G. J. C. & J. D. THomas. 1990. Grazing interactions between pulmonate snails and epiphytic algae and bacteria. Freshwater Biology 23:505-—522. The Veliger 45(1):79—81 (January 2, 2002) THE VELIGER © CMS, Inc., 2002 NOTES, INFORMATION & NEWS Designation of a Lectotype for Succinea grosvenorii Lea (Mollusca: Gastropoda: Pulmonata) Artie L. Metcalf Department of Biological Sciences, University of Texas at El] Paso, El Paso, Texas 79968, USA The description of Succinea grosvenorii Isaac Lea, 1864 (p. 109) consisted of a short diagnosis in Latin and a listing of two collection localities and collectors in- volved.! In the many species described by Lea, the indication ‘“‘“Hab.”’ (Habitat) has traditionally been considered as de- fining a type locality for the species. However, in the case of Succinea grosvenorii, two localities were listed (1864: 109): *“Hab.—Santa Rita Valley, Kansas? Mr. H. C. Gros- venor; and Alexandria, Lousiana, J. Hale, M.D.’ An ob- jective of this paper is to establish a single type locality for this species. Lea (1867:135) noted “‘From the two habitats I have some twenty specimens.’’ He described those from Santa Rita Valley, Kansas, as being “‘all dead shells and opaque white from partial decomposition.”’ In contrast, those from Alexandria, Louisiana, he depicted as shells “‘in a perfect state’’ and of a “‘fine bright straw color.” Both of these lots are in collections of the Na- tional Museum of Natural History. Dr. Robert Hershler, of the museum, reports that the seven whitish specimens from Santa Rita Valley (USNM 121065) are likely sub- fossil. The 13 specimens from Alexandria, Louisiana (USNM 117878) still retain the straw color attributed to them by Lea. These latter specimens have been separated into two lots, with 12 shells in one box and a single one in another box. Before discussing labels found in these boxes, I summarize some notes concerning the Lea Col- ' The patronymic specific name (for H. C. Grosvenor) termi- nated in -ii, the spelling also utilized by Lea (1867:135) in an amplified discussion of this species. Subsequently, the -i ending was used by various other authors including Pilsbry’s catalogue of land snails (1898:143), and even later, as in Shimek (1935). However, Pilsbry & Ferriss used the single -i as early as 1906, as did Pilsbry also in his monograph of North American land mollusks (1948:819). In the synonymy of the species in the monograph, he erroneously indicated that the -i spelling had been employed in Lea’s original description. Subsequent authors have followed Pilsbry’s example (1948), and employed the single -i ending, as in Turgeon, ed. (1998:146). Article 33.4 of the fourth edition of the International Code of Zoological Nomenclature (2000:43) indicates that the use of an -i ending for a species name originally and correctly employing the -ii ending is incor- rect. Thus, in this species it seems clear that the correct specific name is grosvenoril. lection of the National Museum, these also provided by Dr. Hershler. The National Museum did not acquire the large Isaac Lea Collection until after Lea’s death in 1886. These were mainly in the form of syntype lots. At the time of World War II, for safekeeping, attempts were made to separate out from syntype lots those specimens thought to have been illustrated by Lea in his various publications. These were referred to as “figured holotypes,”’ seemingly as- suming that Lea had intended them as such. There exists such a “figured holotype” in the case of S. grosvenorii. Of the two boxes with shells of S. grosvenorii, noted above, one box contains 12 specimens that were referred to as paratypes, and the other box contains a single spec- imen, slightly larger than any of the “‘paratypes,”’ and which is labeled as a figured holotype. There is a single label in the box of “‘paratypes’’ and two labels in the other box with the single specimen. For convenience, these labels are numbered 1—3, below. Label 1. This label is in the box with 12 shells. It is written on a museum label preprinted with “‘U. S. Nat. Mus.” and “‘Lea Coll.’” Handwritten is: 117878 Succinea grosvenori Lea. PARATYPES Alexandria, La. Hale. Perhaps this label was written at the time, in the 1940s, noted above, when “‘types’’ were separated for safekeep- ing. Label 2. This is one of two labels in the box with a single specimen. This is also a USNM label and with the designations ““U. S. Nat. Mus.” and ‘Isaac Lea Coll.” The words “FIG’?D HOLOTYPE” appear in printed handwriting. The other words are in an elegant, cursive style, with flourishes embellishing capital letters, a style still common at least until the latest 1800s. 117878 Succinea Grosvenori, Lea FIG’D. HOLOTYPE. Alexandria La. Hale As this is a National Museum label, it must postdate the time of Lea’s death in 1886, after which Lea’s collection was acquired by the museum. Perhaps it is even later than 1906, when Pilsbry, at least, had started to use the spell- ing grosvenori. However, the marked difference in styles of handwriting would suggest that the part of the label in cursive hand was written earlier than the printed words “FIG’D HOLOTYPE,” which might have been inserted on an empty line in the 1940s, as discussed above. Label 3. This label is in the same box as Label 2. The paper is yellowed with age, and the right side of the label Page 80 the Vieliger) Vol. 45, Nom seems to have been torn off, rather than cut. This is not a preprinted USNM label, but is simply blank paper with handwriting, of which the ink is greatly faded. Some words, indicated by (?), are only tentatively identified be- low. Except for a USNM number written at the bottom of the label in printed handwriting, the remainder is in a cur- sive style, but less elegant than that exhibited in Label 2. April 64 Succinea grosvenorii Lea 108 Near to S. luteola Gould but differs so (?) probably (?) new [‘‘ovalis Say” is written above “‘luteola Gould,” per- haps meant as an insert] q. V. campestris Say Dr. Hale Alexandria, Louisi [end of word torn off] USNM 117878 [in printed handwriting, more modern- appearing than that above] In regard to label 3, April 1864, is the month of pub- lication of the original description of S. grosvenorii by Lea, as noted above. The number given to the figure of the species in Lea’s Observations. . . series (1867: pl. 24) is 108. The presence of this number on the label suggests that it was meant to designate a single specimen rather than the entire lot of syntypes. One might also suspect that Lea himself separated out the specimen and wrote the label. The terse allusions made to related species fa- vor this view, although it is also possible that these re- marks were written later at the National Museum by a curator with an interest in succineids. Regardless of authorship and history of the above la- bels, it is surely clear that the “‘straw-colored”’ syntypes, including the ““FIG7D HOLOTYPE,” are from Alexan- dria, Louisiana. Obviously they are not from “‘Santa Rita Valley, Kansas.”’ This locality was followed by a question mark even in Lea’s original description. In a search by Ms. Grace Muilenburg, a specialist on the history of Kan- sas, no place-name incorporating the name Santa Rita was found within the present or former confines of that state. The place-name does occur in New Mexico and is com- mon in northern México. In the absence of a formally defined holotype for Suc- cinea grosvenorii, 1t seems appropriate to designate the single shell indicated by labels 2 and 3 above as a lec- totype. This is done hereby. This specimen (Figure 1) is still in excellent condition and seems likely to be the one that was chosen by Lea as an exemplar meriting illustra- tion. It has almost the same dimensions as the illustration itself in figure 108 in Lea (1867: pl. 24). As the largest of the 13 syntypes, it seems highly likely that Lea gave it this special recognition, as has at least one curator since then, and it seems fitting to continue that ‘‘tradition.’’ As per ICZN Recommendation 76A.2, this action has the desirable effect of formally establishing the type locality of Succinea grosvenorii at Alexandria, Louisiana, as has been suggested informally by Hubricht (1963:135). This action also invalidates the enigmatic Santa Rita Valley Figure 1. Lectotype of Succinea grosvenorii Lea, 1864. United States National Museum number is 117878. Some dimensions (in mm) of the shell are: height, 13.0; width, 7.9; height of ap- erture, 8.3; and width of aperture, 5.8. locality as a contender for type locality. The USNM num- ber for the lectotype remains 117878. The lot of 12 par- alectotypes (indicated by Label 1, above), all of which are judged to be of the same species as the lectotype, is renumbered USNM 880662. Height of the lectotype is 13.0 mm. Other dimensions are indicated in Figure 1. The 12 paralectotypes range in height from 9.2 to 12.5 mm with a mean of 11.2 mm. I thank Dr. Robert Hershler, National Museum of Nat- ural History, for the loan of specimens and for providing the photograph in Figure 1, and I thank both him and Dr. Shi-Kuei Wu, University of Colorado, for useful sugges- tions. I am grateful to Dr. Elizabeth Walsh and Ms. Laura Dader, University of Texas at El Paso, for assistance in making prints. Literature Cited Hupricut, L. 1963. Some Succineidae, with a new species. The Nautilus 76:135—138. Lea, I. 1864. Description of six new species of SUCCINEA of the United States. Proceedings of the Academy of Natural Sciences of Philadelphia 16:109-111. Lea, I. 1867. Observations on the genus Unio, together with de- scriptions of new species in the family Unionidae, and descrip- tions of new species of the Melanidae, Limneidae, Paludinae and Helicidae. Philadelphia (printed for the author) 11:1—146. PitsBry, H. A. 1898. A classified catalogue of American land shells, with localities (concluded). The Nautilus 11:138—144. Notes, Information & News Page 81 Pitssry, H. A. 1948. Land Mollusca of North America (north of Mexico). The Academy of Natural Sciences of Philadelphia Monographs 3 (II, 2): i-xlvii + 521-1113. Pitssry, H. A. & J. H. Ferriss. 1906. Mollusca of the south- western states. II. Proceedings of the Academy of Natural Sciences of Philadelphia 58:123-175. SHIMEK, B. 1935. The habitats of Iowa succineas. The Nautilus 49:6-10. TuRGEON, D. D. (ed.) 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks 2nd ed. American Fisheries Society Special Pub- lication 26:1—526. International Commission on Zoological Nomenclature The following Applications concerning mollusks were published on 28 September 2001 in Volume 58, Part 3 of the Bulletin of Zoological Nomenclature. Comment or ad- vice on any of these applications is invited for publication in the Bulletin and should be sent to the Executive Secretary, I.C.Z.N., % The Natural History Museum, Cromwell Road, London SW7 5BD, U.K. (e-mail: iczn@nhm.ac.uk). Case 2983. Achatinellastrum Pfeiffer, 1854 and ACHA- TINELLIDAE Gulick, 1873 (Mollusca, Gastropoda): proposed conservation. Case 3192. BULIMINIDAE Kobelt, 1880 (Mullusca, Gastropoda): proposed emendation of spelling to BU- LIMINUSIDAE, so removing the homonymy with BU- LIMINIDAE Jones, 1875 (Rhizopoda, Foraminifera); and ENIDAE Woodward, 1903 (1880) (Gastropoda): proposed precedence over BULIMINUSIDAE Kobelt, 1880. Case 3153. HIPPOPODIIDAE Cox, 1969 (Mollusca, Biv- alvia): proposed emendation of spelling to HIPPOPO- DIUMIDAE, so removing the homonymy with HIP- POPODHDAE KoOlliker, 1853 (Cnidaria, Hydrozoa). The following Opinion concerning mollusks was pub- lished on 29 June 2001 in Volume 58, Part 2 of the Bulletin of Zoological Nomenclature. Copies of Opinions can be obtained free of charge from the Executive Secretary, LC.Z.N., % The Natural History Museum, Cromwell Road, London SW7 SBD, U.K. (e-mail: - iczn @nhm.ac.uk). Opinion 1973 (Case 3126). Bulinus wrighti Mandahl- Barth, 1965 (Mollusca, Gastropoda): specific name conserved. The following Opinions concerning mollusks were pub- lished on 28 September 2001 in Volume 58, Part 3 of the Bulletin of Zoological Nomenclature. Opinion 1979 (Case 3086). Hyalinia villae adamii Wes- terlund, 1886 (currently Oxychilus adamii; Mollusca, Gastropoda): specific name adamii conserved by the replacement of the syntypes with a neotype. Opinion 1980 (Case 3088). Doris verrucosa Linnaeus, 1758 (Mollusca, Gastropoda): generic and_ specific names conserved by the designation of a neotype. Opinion 1981 (Case 3133). Peristernia Morch, 1852 and Clivipollia Iredale, 1929 (Mullusca, Gastropoda): con- served by the designation of Turbinella nassatula La- marck, 1822 as the type species of Peristernia. The Veliger 45(1):82-83 (January 2, 2002) DHE VELIGER © CMS, Inc., 2002 BOOKS, PERIODICALS & PAMPHLETS Evolutionary Biology of the Bivalva edited by E. M. Harper, J. D. TAYLOR & J. A. CRAME. 2000. Geological Society Special Publication No. 177. The Geological Society, Burlington House, Piccadilly, London, United Kingdom WIV OJU. 494 pp. Evolutionary Biology of the Bivalvia represents the most important volume on this topic to be published in the 20 years since “‘Evolutionary systematics of bivalve molluscs” (1978. Philosophical Transactions of the Royal Society of London, B. pp. 199-436). The text follows closely on the heels of Johnston & Haggart (1998), and together these volumes summarize the current state of our knowledge of the evolution of the Bivalvia. However, whereas the Johnston & Haggart volume (1998) had the distinct feeling of a volume compiled after a 20 year hi- atus (albeit an important compilation), the current text is more definitive in its impact. The opening papers by Steiner & Hammer (**Molecular phylogeny of the Bivalvia inferred from 18S rDNA se- quences with particular reference to the Pteriomorpha’’) and Campbell (*“‘Molecular evidence on the evolution of the Bivalvia’) report on molecular-based cladistic anal- yses (18S rDNA) of overall bivalve phylogeny, the di- vergence of major divisions such as the Pteriomorpha and Heteroconchia, and the possible evolutionary roots of the Bivalvia. These reports are an important step forward in addressing bivalve phylogeny at all levels, and can only be expected to improve as the number of sequenced taxa increases. Both studies also complement well previous morphology-based analyses, such as the outstanding re- port by Waller (1998). Waller’s conclusions, based on de- tailed observational analyses of morphological (including conchological) and developmental characters, are corrob- orated significantly at higher taxonomic levels by the mo- lecular analyses. This highlights the indisputable value of molecular analyses; they utilize data that are independent of morphological characters (in an analytical, not biolog- ical sense), and therefore “‘are less selected by lifestyle and habitat than is morphology’? (Steiner & Hammer). Nevertheless, our reconstruction of bivalve phylogenies cannot rely upon molecules alone, since that would ignore the wealth of understanding of the developmental and functional bases of shell morphology, a long tradition of soft-anatomical work, and a fossil record that is one of the best for any metazoan taxon. This point is emphasized by many of the remaining phylogenetic papers in the volume. There are higher level phylogenetic reconstructions based on morphological data (Carter et al.), as well as detailed and current investiga- tions of the phylogenetic importance and origin of early Paleozoic taxa (Cope). Bivalvia is one of only a handful of taxa with Cambrian and Ordovician records rich enough to permit such reconstructions. The work is ham- pered, however, by factors such as character interpreta- tions, time-dependent convergence, and preservation. In- creased gene sequencing will ultimately circumvent many of these problems, but morphological and paleontological studies must continue; in one sense, molecular analyses are both easier and evolutionarily less illuminating. We have solid theoretical models of sequence evolution upon which to base parsimony and maximum likelihood anal- yses, though we lack the information necessary to under- stand most of the phenotypic implications of that evolu- tion. Morphology-based analyses unfortunately lack the models of character state transformation that are at the heart of gene sequence-based analyses. Hopefully, this situation will change with the eventual work on devel- opmental genetics and gene function in bivalve taxa. Un- til that time, however, morphological interpretations must continue to rely upon ecological, functional morphologi- cal, developmental, and morphometric analyses. Fortunately, these all find impressive representation in the volume. Following the phylogenetic analytical papers are a series of contributions examining the evolutionary biology of a variety of bivalve characters. These charac- ters range from cell and tissue-level examinations of sperm, sensory structure, gastric and respiratory struc- tures, to theoretical and empirical functional examinations of shell structure and mechanics. While most of these studies are at the rank of family or above, there are a number of papers dealing with generic and species-level taxa. The focus here is primarily on examinations of ge- netic and phenotypic variation, or the environmental ba- ses of such variation; these topics have been traditionally well represented in bivalve research, and the tradition continues in the present volume with the application of new tools, such as nuclear DNA variation and modern morphometric analysis. Finally, analyses of biogeographic patterns and region- al biodiversity by Crame, Jablonski et al., and Mikkelesen & Bieler emphasize the broad applicability of bivalve bi- ology. This point in fact highlights the dual nature of this volume. This text presents many of the most current ideas explaining the evolution of the Bivalvia at multiple levels. While these studies advance our knowledge of this im- portant taxon, they also serve notice that major contri- butions to our understanding of animal evolution, evolu- Books, Periodicals & Pamphlets tionary ecology, biogeography, and paleobiology/paleo- ecology will continue to be made by bivalve workers. In the end, however, the reader is left with the distinct and correct impression that our understanding of these topics as they apply to the Bivalvia (and vice versa) is still very incomplete. And that, perhaps, will be the most signifi- cant contribution of this volume to the next 20 years of research. Peter D. Roopnarine LITERATURE CITED JOHNSTON P. A. & J. W. HAGGART, eds. 1998. Bivalves: An Eon of Evolution. University of Calgary Press: Calgary. xiii + 461 pp. WALLER, T. R. 1998. Origin of the molluscan class Bivalvia and a phylogeny of major groups. Pp. 1—46 in P. A. Johnston & J. W. Haggart (eds.), Bivalves: An Eon of Evolution. Uni- versity of Calgary Press: Alberta, Canada. Tropical Deep-Sea Benthos, Volume 22 edited by PHILIPPE BOUCHET & BRUCE A. MARSHALL. 2001. Mémoires du Muséum National d’Histoire Natu- relle 185:1—407, 638 figures, 4 color plates. ISBN 2- 85653-527-5. The series Tropical Deep-Sea Benthos, a continuation of Résultats des Campagnes MUSORSTOM, is dedicated to inventorying and describing the deep ocean faunas of the world, with special emphasis on the Indo-Pacific realm. The present volume is the fourth ‘‘all-mollusk”’ volume in the series (previous ones being: 7 [1991], 14 [1995], and 19 [1998]). It contains contributions by ex- Page 83 perts from Australia, New Zealand, Belgium, France, the Netherlands, Russia, Taiwan, and the United States, and includes papers on Aplacophora, Polyplacophora, Bival- via, Gastropoda, and Cephalopoda. The contributions are largely based on material col- lected by a series of dredging and trawling expeditions conducted since 1985 in the south Pacific under the lead- ership of Dr. Bertrand Richer de Forges, using the Nou- méa-based Research Vessel Alis. Earlier expeditions cov- ered New Caledonia, Vanuatu, Fiji, Wallis and Futuna, Tonga, and the Marquesas. Plans for the coming years include the Solomon and Austral Islands. Series editor Philippe Bouchet (in litt.) estimates that the resulting south Pacific deep-sea collections contain on the order of 2000 new molluscan species; it will take many more years and the input of malacologists from all over the world to document and appropriately describe this fauna. Contents of volume 22 include descriptive systematic papers on Prochaetodermatidae (Aplacophora) by D. L. Ivanov and A. H. Scheltema; Polyplacophora by B. Sir- enko; bathyal Pectinoidea (Bivalvia) by H. H. Dijkstra; the limid genus Acesta (Bivalvia) by B. A. Marshall; Spondylidae (Bivalvia) by K. L. Lamprell and J. M. Hea- ly; Poromyidae (Bivalvia) by E. M. Krylova; Triviidae (Gastropoda) by L. Dolin; Muricidae (Gastropoda) by R. Houart; turriform gastropods by A. Sysoev and P. Bouch- et; deep-water Pleurobranchaeidae (Gastropoda) by B. Dayrat; phylidiid nudibranchs (Gastropoda) by A. Valdés; and cephalopods from waters around Wallis and Futuna by C.-C. Lu and R. Boucher-Rodoni. Other volumes in Tropical Deep-Sea Bethos deal with other groups of marine invertebrates and fishes. An over- view can be seen on the website of the Muséum National d’Histoire Naturelle, www.mnhn.fr/publication/memoire/ mem.html. | i | SS > : | . 7 | data atau a! Sipe | a | ee 4 t t ° | . io | all 4c okie Information for Contributors Manuscripts Manuscripts must be typed, one side only, on A4 or equivalent (e.g., 842” X 11”) white paper, and double-spaced throughout, including references, figure legends, footnotes, and tables. 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Submitting manuscripts Send manuscripts, proofs, books for review, and corre- spondence on editorial matters to Dr. Barry Roth, Editor, 745 Cole Street, San Francisco, CA 94117, USA. CONTENTS — Continued Mass exhumation and deposition of Mulinia lateralis (Bivalvia: Mactridae) on an intertidal beach, St. Catherines Island, Georgia, USA CAROL M. CLEVELAND, ROBERT S. PREZANT, HAROLD B. ROLLINS, RONALD TOLL, AND JEN NIBER SW YQIE Senso re se: Ste late cates out once sented acelin ete kel te gninee emer ate nn ES Pe The natural diet of the Argentinean endemic snail Chilina parchappii (Basommatophora: Chilinidae) and two other coexisting pulmonate gastropods A. 1. ESTEBENET, NJ CAZZANIGA, -ANDSIN NV PIZANT ote otic ee ene NOTES, INFORMATION & NEWS Designation of a lectotype for Succinea grosvenorii Lea (Mollusca: Gastropoda: Pulmonata) PARTIE Ts IME T CAME 32 cose ce canes ee Gos stat penesttos eR Ee nee ola a 65 71 79 82 PELIGER A Quarterly published by CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. Berkeley, California R. Stohler (1901—2000), Founding Editor Volume 45 ISSN 0042-3211 April 1, 2002 CONTENTS The genus Nodilittorina von Martens, 1897 (Gastropoda: Littorinidae) in the eastern Pacific Ocean, with a discussion of biogeographic provinces of the rocky-shore fauna IDA) (Gre, TRUESO Oo cece sat ora aa Ieglh ae Ea on eas eae SE eee ee ete ran de Ieee a er Pee 85 NOTES, INFORMATION & NEWS A useful marker for the study of neural development in cephalopods SHUIEHI¢ SEIGENO@PAND | VIASAMICHIN VAMAMOTO™ 015 <2 cies ie casi ees sae eee WA Crepidula dilatata Lamarck, 1822, truly living in the southwestern Atlantic PABLO E. PENCHASZADEH, GUIDO PASTORINO, AND MAXIMILIANO CLEDON.......... 2 BOOKS seERIODICAIES Se PAMIPIMUE NS) fasts oahis were ess ois oles 6 gee hed es 5 The Veliger (ISSN 0042-3211) is published quarterly in January, April, July, and October by the California Malacozoological Society, Inc., % Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105. Periodicals postage paid at Berkeley, CA and additional mailing offices. POSTMASTER: Send address changes to The Veliger, Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105. Number 2 THE VELIGER Scope of the journal The Veliger is an international, peer-reviewed scientific quarterly published by the Cali- fornia Malacozoological Society, a non-profit educational organization. The Veliger is open to original papers pertaining to any problem connected with mollusks. 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Send manuscripts, proofs, books for review, and correspondence regarding editorial matters to: Dr. Barry Roth, Editor, 745 Cole Street, San Francisco, CA 94117, USA. © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). THE VELIGER © CMS, Inc., 2002 The Veliger 45(2):85-170 (April 1, 2002) The Genus Nodilittorina von Martens, 1897 (Gastropoda: Littorinidae) in the Eastern Pacific Ocean, with a Discussion of Biogeographic Provinces of the Rocky-Shore Fauna DAVID G. REID Department of Zoology, The Natural History Museum, London SW7 S5BD, United Kingdom Abstract. The Recent members of the genus Nodilittorina in the eastern Pacific Ocean are revised. Hitherto eight to 10 species have been recognized, but this total is now increased to 18, of which three are named as new. The majority of the taxa fall into three species complexes: six in the N. porcata group, two in the N. modesta group, and six in the N. aspera group. Within each of these complexes, species identification from shells alone is difficult, as a result of remarkable intraspecific variation. Since all species of the genus have pelagic eggs and planktotrophic development, it is suggested that this variation may be partly of ecophenotypic origin. Discrimination is confirmed by species-specific characters of the penis and supported by some features of the spermatozoa and pallial oviducts. Radular characters are more constant throughout the genus. The four additional species are N. araucana, N. peruviana, N. galapagiensis, and N. fernandezensis. Anatomical features, radulae, and a range of shells are figured for each species. Geographical distri- butions are mapped in detail (from 777 samples examined) and cases of sympatric occurrence provide strong support for the discrimination of members of the three species complexes. There is insufficient morphological differentiation among the species to permit formal phylogenetic analysis. Some of them show similarities with congeners in the western Atlantic, but there are no obvious sister-species pairs. A species endemic to the oceanic islands off Chile, N. fernandezensis, shows a clear relationship with a largely temperate Southern Hemisphere group, the subgenus Austrolittorina (here redefined). Of particular interest are the distributions of the 15 Nodilittorina species within the Tropical Eastern Pacific Region (TEP; hitherto referred to as the ‘“‘Panamic Province”’ in the molluscan literature). These strongly support the classification of the region into four provinces, Cortez, Mexican, Panamic (with a southern Ecuadorean element), and Galapagos, as previously suggested for fishes, which (like Nodilittorina species) are dependent upon shallow-water rocky substrates. The boundaries between these provinces correspond with habitat gaps, of either open water (Galapagos) or inhospitable coastline of sand, mud, and mangroves (Sinaloan, Central American and Colombian Gaps). The implications for processes of dispersal and speciation, and also for future systematic studies of the rocky-shore fauna, are discussed. INTRODUCTION Washington (Reid, 1996), and Cenchritis muricatus (L.) has been introduced to the Gulf of California (Bishop, 1992; Chaney, 1992). Recently, three tropical species of Indo-West Pacific origin have been recorded from the eastern Pacific for the first time, two of Littoraria and one of Peasiella, but these appear to be only occasional immigrants (Reid & Kaiser, 2001). Nodilittorina is the largest genus in the family Litto- rinidae, with an estimated 60 species worldwide. Most of these are tropical, and in the temperate northern hemi- The eastern Pacific Ocean stretches from the shores of Alaska to Tierra del Fuego, and includes tropical islands as far west as the Islas Revillagigedo, Clipperton Atoll, the Galapagos, and the Juan Fernandez Archipelago. Within this expanse there occur three principal genera of the littorinid subfamily Littorininae (using the classifica- tion of Reid, 1989a). The northern temperate genus Lit- torina includes seven native species in this region, of which two extend as far south as Baja California (Reid, 1996). The genus Littoraria is exclusively tropical and includes five species from mangrove habitats and one sphere they are replaced (with little geographical overlap) by species of Littorina. In contrast, in the southern hemi- from rocky shores (Reid, 1999a). The remaining members of the subfamily that are of native occurrence and main- tain reproducing populations are all members of the genus Nodilittorina; these can be found from Baja California to southern Chile and on all the oceanic islands. In addition to these eastern Pacific natives, there are three introduced Littorina species recorded from San Francisco Bay and sphere, Nodilittorina species extend throughout the tem- perate latitudes. All the species occur typically on inter- tidal rocks, usually in the littoral fringe and upper eulit- toral zone, where they graze on epilithic and endolithic algae. They are usually the dominant large invertebrates at these levels on the shore, and have therefore been the subject of much work on ecology and physiology. Ex- Page 86 The Veliger, Vol. 45, No. 2 amples include studies in Australia (Underwood & McFadyen, 1983; Chapman, 1994, 1998), South Africa (McQuaid, 1981la, b, 1992), Hong Kong (Ohgaki, 1985; Mak, 1998: Mak & Williams, 1999), Japan (Ohgaki, 1988, 1989), Hawaii (Struhsaker, 1968), the Mediterra- nean (Palant & Fishelson, 1968), Brazil (de Magalhaes, 1998), and the Caribbean (Borkowski, 1974; Britton, 1992; Lang et al., 1998; see also McQuaid, 1996b, for a review of littorinid ecology). The ecology of these litto- rinids has, however, received relatively little attention in the eastern Pacific region (Vegas, 1963; Markel, 1971: Vermeij, 1973; Jordan & Ramorino, 1975; Garrity & Lev- ings, 1981; Garrity, 1984), although they have often been mentioned in studies of littoral zonation (Hedgpeth, 1969; Cinelli & Colantoni, 1974; Paredes, 1974; Romo & Al- veal, 1977; Santelices et al., 1977; Brattstr6m, 1990). Despite this ecological importance, the taxonomy of Nodilittorina species remains poorly understood. As dis- cussed below, even a satisfactory definition of the genus is not available. There have been no modern studies of the systematics of this group in the eastern Pacific. The first species to reach European collections was the Peru- vian N. peruviana, named by Lamarck (1822), and on his great South American journey, d’Orbigny (1835-1846) obtained both this and the Chilean N. araucana. Further material was brought back by Cuming, from which Phi- lippi (1846a) described three tropical species. There soon followed taxonomic studies on material from Mexico (Menke, 1851; Carpenter, 1857b, 1864a), Central Amer- ica (C. B. Adams, 1852a, b; M@grch, 1860; Carpenter, 1863; von Martens, 1900), and the Galapagos (Stearns, 1892, 1893a, b). Meanwhile, monographs of worldwide littorinids had appeared in the great nineteenth century conchological iconographies (Philippi, 1846b—1848; Ktis- ter, 1853, 1856; Reeve, 1857-1858; Weinkauff, 1878, 1882; Tryon, 1887). With limited material available, the earlier authors distinguished many shell variants as spe- cies; for example, Philippi (1847) included eight in this eastern Pacific group. Later, the trend was to synonymize many names; Weinkauff (1883) accepted only six of Phi- lippi’s taxa, Tryon (1887) only four, and Dall (1909) like- wise had a broad concept of species in this group. Twen- ty-eight names were introduced in the nineteenth century, and three more in the twentieth (Bartsch & Rehder, 1939; McLean, 1970; Rosewater, 1970). For much of the twen- tieth century, authors continued to accept a wide degree of intraspecific variation in species that were defined by shell characters alone, so that the influential Sea Shells of Tropical West America by Keen (1971, following tax- onomy of Rosewater, 1970) included only eight (plus sev- en additional names listed uncritically as Fossaridae, see discussion of N. porcata group). This book has been the basis for several regional faunal lists (Finet, 1985, 1994: Alamo & Valdivieso, 1987, 1997; Kaiser, 1997). The modern taxonomy of the Littorinidae has been trans- formed by the use of anatomical and radular characters, correlated with details of shell sculpture and pattern (e.g., Bandel & Kadolsky, 1982; Reid, 1986, 1989a, 1996), and this has led to a proliferation of recognized species and to more rigorous phylogenetic definitions of genera. In a list of worldwide Littorinidae Reid (1989a) gave eight species in this eastern Pacific group (with two additional species doubtfully in synonymy) and, for the first time, all were included together in Nodilittorina. Many workers have commented on the confusing var- iability and uncertain taxonomy of the littorinids of the eastern Pacific, especially those related to Nodilittorina porcata and N. aspera. In 1971 Keen remarked of “‘Lit- torina aspera’ that “it is possible that careful work will demonstrate the desirability of recognizing more than one species within this complex.’’ However, despite advances in littorinid taxonomy in other parts of the world, the eastern Pacific Nodilittorina species have remained ne- glected. The present study aims to revise the taxonomy of this group, based on personal field collections and ex- amination of the major museum collections. Particular emphasis is placed on characters of the reproductive sys- tem (penis, paraspermatozoa, pallial oviduct, egg cap- sules) which are known to be important for the discrim- ination of littorinid species (Reid, 1986, 1996, 1999a). Fossil material has not been included. In general, fossil littorinids are extremely scarce, as expected for a group living primarily on hard intertidal substrates. Further- more, the shells of Nodilittorina species are so variable and also show such close resemblance to some members of Littoraria and Littorina, that fossil material would be difficult to interpret. The only possible fossil member of the genus Nodilittorina that has been recorded from trop- ical America is Littorina seminole Petuch from the Plio- cene Caloosahatchee Formation of Florida (Petuch, 1991). As a result, 18 Nodilittorina species are recognized in the eastern Pacific Ocean, where hitherto only eight to 10 were generally accepted. Their geographical distributions are plotted in detail, and congruent patterns among spe- cies complexes, as well as cases of sympatry, provide support for the new species definitions. Of particular in- terest are the distributions of the 15 species within the Tropical Eastern Pacific Region (TEP) which suggest its division into four provinces, Cortez, Mexican, Panamic, and Galapagos. Although this division has previously been recognized in some other animal groups, in the mol- luscan literature the entire TEP has been regarded as uni- form and referred to as the “‘Panamic Province.” The boundaries between these provinces correspond with hab- itat gaps, of either open water or inhospitable coastline of sand, mud, and mangroves. The recognition of these gaps has important implications for systematic, evolu- tionary, and genetic studies of the rocky-shore fauna. MATERIALS AND METHODS During this study, all material in the collections of the following institutions has been examined: the Natural D. G. Reid, 2002 History Museum, London (BMNH), the National Muse- um of Natural History, Smithsonian Institution, Washing- ton, D.C. (USNM), the Muséum National d’ Histoire Na- turelle, Paris (MNHNP), and the Zodlogisch Museum, Amsterdam (ZMA). Much additional material, of species and from geographical regions that were otherwise poorly represented, has been obtained from the Los Angeles County Museum of Natural History (LACM), the Cali- fornia Academy of Sciences (CAS), the Charles Darwin Research Station, Ecuador (CDRS) and the personal col- lections of K. L. Kaiser (KLK) and G. J. Vermeij. All available primary type material has been examined (in one case a photograph) from these institutions, and also from the Academy of Natural Sciences of Philadelphia (ANSP), the Museum of Comparative Zoology, Harvard University (MCZ), the Muséum d’ Histoire Naturelle, Ge- neva (MHNG), the Museum fiir Naturkunde, Berlin (MNB), and the Forschungsinstitut und Naturmuseum Senckenberg, Frankfurt (SMF). Paratypes of some spe- cies are housed in the American Museum of Natural His- tory (AMNH) and in the Santa Barbara Museum (SBM), but these were not examined. Personal collections were made in Costa Rica (1985), Mexico (1994), Chile and Peru (1998), and Ecuador (1998), and are deposited in BMNH. In total, 777 samples have been examined. Fossil material is extremely scarce and has not been included in this study. Shell dimensions were measured with vernier calipers or, for the smallest species, with a camera lucida and scale, to 0.1 mm. Shell height (H) is the maximum di- mension parallel to the axis of coiling, shell breadth (B) the maximum dimension perpendicular to H, and the length of the aperture (LA) the greatest length from the junction of the outer lip with the penultimate whorl to the anterior lip. Shell shape was quantified as the ratios H/B and H/LA (relative spire height, SH), and the range of these ratios is quoted. Shell sculpture is described by reference to primary and secondary grooves, ribs, the pe- riphery, and microstriae. Primary grooves are incised spi- ral lines or grooves that are visible on the early teleo- conch whorls. On the spire the primary grooves are counted between successive sutures, but on the last whorl they are counted from the suture to the periphery of the whorl (so that one or more extra grooves are visible). Secondary grooves appear by interpolation, usually on the penultimate or final whorl, and sometimes not at all. The spaces between the grooves are referred to as ribs, whether or not they are strongly raised. Microstriae are fine incised spiral lines that cover the entire surface and are visible only under low magnification; they may be present in addition to primary grooves, but in the smallest species (the N. porcata group) the distinction between primary grooves and microstriae is sometimes arbitrary. The periphery is the junction between the upper part of the final whorl and the base of the shell; it is usually marked by a strong or slight angulation (e.g., Figure Page 87 18R), or by a rib slightly larger than the rest (e.g., Figure 12B), or more rarely by a keel or flange (e.g., Figure IN). The suture generally runs one or two ribs above the pe- riphery, or is situated at the peripheral rib. Protoconch whorls were counted as recommended by Reid (1996); the protoconch in Figure 22G has 2.7 whorls. To describe the coiling of the operculum, the opercular ratio was de- fined as the ratio of two parallel measurements, the di- ameter of the spiral part divided by the maximum length (Reid, 1996). The relative radular length is the total rad- ular length divided by shell height. Living animals were relaxed in 7.5% (volume of hy- drated crystals to volume of fresh water) magnesium chloride solution. Animals were fixed in 10% seawater formalin buffered with borax, and stored in 80% ethanol before dissection. Anatomical drawings were made by camera lucida, and shading and drawing conventions are indicated in the captions of Figures 3, 4, and 13. For general accounts of the anatomy of littorinids, see Reid (1986, 1989a, 1996). Sperm samples were removed from the seminal vesicles of relaxed, living animals, fixed in 0.5% seawater formalin, examined immediately by light microscopy, and drawn by camera lucida. Alternatively, sperm were removed from specimens fixed and stored in seawater formalin, but not from material stored in ethanol (in which shrinkage of paraspermatozoa by about 20% occurs, Reid, 1996). For four species, egg capsules were obtained by confining individual females in beakers of seawater left overnight; these were drawn using a com- pound microscope and camera lucida. Radulae were cleaned by soaking in a hypochlorite bleaching solution at room temperature for about 5 min, rinsed in distilled water, mounted on a film of polyvinyl acetate glue on glass, allowed to dry in air, and coated with gold and palladium before examination in a scanning electron mi- croscope. Unworn portions of radulae were viewed in three orientations: in standard flat view from vertically above the radula (to show shapes of tooth bases), at an angle of 45° from the front end of the radula (to show shapes of tooth cusps), and at an angle of 45° from the side of the radula (to show relief). The shape of the rach- idian tooth was quantified as the ratio of the total length (in flat view) to the maximum basal width. Synonymies are not exhaustive, but attempt to list all new names (including nomina nuda) and new combina- tions, major taxonomic works and faunistic lists, and sig- nificant morphological descriptions. Where valid names are represented by syntypic series of dry shells, lectotypes have been designated. This is considered necessary for stability, since identification from shells alone can be dif- ficult ICZN, 1999, Art. 74.7.3). Lectotypes are also des- ignated in cases where syntypes are not all conspecific. Distribution maps were plotted from the material ex- amined, with the addition of literature records (where these extended the known range and were considered re- liable). Localities are listed only when they are range lim- Page 88 its or are of other biogeographic significance. Species are common throughout the range except where noted oth- erwise. Numbers of specimens in lots are given only for rare and occasional occurrences at the limits of ranges. EXCLUDED SPECIES Littorina angiostoma C. B. Adams, 1852 Examination of the lectotype (MCZ 186442) from Pan- ama has shown this to be an /selica (Pyramidellidae). It was figured by Turner (1956:pl. 13, fig. 1). Fossarus guayaquilensis Bartsch, 1928 The original figure (Bartsch, 1928:fig. I, 6) shows that this species from Ecuador is indeed a Fossarus (Planax- idae). It should not be confused with the manuscript name “Lacuna guayaquilensis Bartsch” (see Nodilittorina san- telenae sp. nov.). Littorina (Melarhaphe) philippii var. latistrigata von Martens, 1900 Although said to come from western Costa Rica, two unregistered synypes in MNB belong to the Caribbean species Nodilittorina interrupta (C. B. Adams, in Philip- pi, 1847). Littorina (?) megasoma C. B. Adams, 1852 As noted by Turner (1956), this Panamanian shell is a Fossarus. The holotype (MCZ 186419) was figured by Turner (1956:pl. 11, fig. 6). Litorina phasianella Philippi, 1849 This is a species of Tricolia (Turbinidae) (see Keen, 1971) with type locality Panama. Littorina umbilicata d’ Orbigny, 1840 Although sometimes listed as a littorinid (see Taxo- nomic History of N. atrata), examination of the type se- ries (BMNH 1854.12.4.366) shows this species from Peru and Chile to be a Tricolia, as also observed by Keen (1971). SYSTEMATIC DESCRIPTIONS Family LItroRINIDAE Anonymous, 1834 Genus Nodilittorina von Martens, 1897 Littorina (Nodilittorina) yon Martens, 1897:204 (type by subsequent designation, Abbott, 1954, Littorina pyram- idalis Quoy & Gaimard, 1833) Littorina (Echinolittorina) Habe, 1956:96—99 (type by orig- inal designation Litorina tuberculata Menke, 1828; cit- ed as Echinolittiorina in error, p. 96) Granulilittorina Habe & Kosuge, 1966:313-314, 328 (type by monotypy Granulilittorina philippiana Habe & Ko- suge, 1966 = N. vidua (Gould, 1859)) Littorina (Austrolittorina) Rosewater, 1970:467 (type by original designation Littorina unifasciata Gray, 1826) Littorina (Fossarilittorina) Rosewater, 1981:29 (type by original designation Phasianella meleagris Potiez & Michaud, 1838) The Veliger, Vol. 45, No. 2 Taxonomic history: The recognition and definition of the genus Nodilittorina has a long and complex history. In classifying this group, authors have employed characters of the shell, operculum, radula, reproductive anatomy, and egg capsules. Since the groupings suggested by these characters do not coincide, there has been corresponding disagreement about generic classification. The authors of the early icongraphies of littorinids (Philippi, 1846b—1848: Kiister, 1853, 1856, continued by Weinkauff, 1878, 1882; Reeve, 1857-1858) used only the single inclusive genus Liftorina (corresponding to the subfamily Littorininae as currently recognized, Reid, 1989a; intentionally emended to Litorina by some nine- teenth century authors, see Reid, 1996:39). However, Gray (1839, 1847) had already advocated removal of the large, spinose species with mesospiral or multispiral oper- culum (corresponding to Tectarius; see Reid & Geller, 1997, for history of this genus), while retaining small, nodulose species with typical paucispiral operculum (e.g., Nodilittorina trochoides (Gray) and N. pyramidalis in current classification) in Littorina (Gray, 1839, 1857). This system was modified by Adams & Adams (1854); of the current members of Nodilittorina, those with non- descript turbinate shells were retained in Littorina, those more elongate and brightly patterned were separated as the subgenus Melarhaphe, whereas those with nodulose sculpture were added to the genus Tectarius. A similar division, based on shell and opercular characters, was fol- lowed by Tryon (1887). Troschel (1858; followed by Weinkauff, 1883) divided current Nodilittorina species between Littorina (Littorina) and Littorina (Tectus) (= Tectarius) and, although this was based on the supposed narrow rachidian tooth of the latter, and opercular differ- ences, it corresponded once again to a distinction between relatively smooth-shelled and nodulose forms. Shell char- acters likewise provided a poor guide to the relationships of a neglected group of small, umbilicate shells (here re- ferred to as the N. porcata group), variously referred to Littorina (Philippi, 1846a, 1847; C. B. Adams, 1852a, b), Fossar (Adams & Adams, 1854), Fossarus (Carpenter, 1863; Tryon, 1887; Keen, 1971), and several other gen- era. The name Nodilittorina was introduced by von Martens (1897), as a subgenus of Littorina, for those species with nodulose sculpture but a “‘typical”’ aperture and opercu- lum (therefore in contrast to Littorina (Tectus) with a col- umellar tooth and rounded, many-whorled operculum). Although this new subgenus was accepted in the influ- ential classification of Thiele (1929; followed by Wenz, 1939; Clench & Abbott, 1942), it was placed in Tectarius on account of the narrow central tooth, and despite dis- similarity in the operculum. Meanwhile, the use of Lit- torina (Melarhaphe) for the elongate, patterned species was well established (von Martens, 1897, 1900; Thiele, 1929; Wenz, 1939; Bequaert, 1943). In 1954 Abbott made an important advance by including details of the form of D. G. Reid, 2002 Page 89 the penis and of egg capsules in his revision of littorinid genera. On this basis he raised Nodilittorina to a full ge- nus and showed clearly that it was more closely related to ‘“‘Littorina (Melarhaphe) ziczac (Gmelin)”’ (1.e., the N. ziczac group of the western Atlantic) than to Tectarius. Abbott (1954) also noted that “L.”? ziczac and “‘L. maur- itiana”’ (a misidentification of N. unifasciata) might well not belong to L. (Melarhaphe), depending upon the penial shape of its type species, M. neritoides (L.). Shortly af- terward, Habe (1956) introduced the subgenus N. (Echinolittorina) for N. tuberculata, because its rachidian tooth was narrower than that of the type of Nodilittorina (N. pyramidalis). The new genus Granulilittorina was subsequently added by Habe & Kosuge (1966) for a spe- cies with unusual serrated egg capsules (N. vidua). In two monographs of Indo-Pacific littorinids, Rose- water (1970, 1972) included a worldwide list of species and presented a revised generic classification. Although characters of penis, egg capsule, and radula were consid- ered, this scheme still emphasized similarities of shell sculpture. Thus the smooth-shelled species currently as- signed to Nodilittorina were distributed among five sub- genera of Littorina, the nodulose forms placed in Nodi- littorina s.s. and its subgenus Echinolittorina, and gran- ulose species in N. (Granulilittorina). Rosewater (1970) noted that while nodulose sculpture was “‘the most ob- vious character of Nodilittorina”’ it showed considerable variability within some species. Nevertheless, smooth- shelled species with penes closely similar to those of No- dilittorina species were placed in a new subgenus Litto- rina (Austrolittorina). This scheme was widely followed (e.g., Keen, 1971; Abbott, 1974). Additional information on penes and radulae resulted in transfer of three more members to Austrolittorina from the subgenus Littoraria (Ponder & Rosewater, 1979). A further modification (Rosewater, 1981) was the description of another new subgenus, Fossarilittorina, for the small, umbilicate spe- cies, but this was still assigned to Littorina. It was not until the work of Bandel & Kadolsky (1982) on western Atlantic Nodilittorina species that the genera of Littorinidae were revised to take account of all avail- able evidence. Using published accounts of penes, spawn, and development, and new information on radulae, oper- cula, and shell mineralogy, they redefined Nodilittorina to include, for the first time, both smooth-shelled and nodulose species. They showed not only that shell sculp- ture was a poor indication of relationships, but also that the rachidian tooth and operculum (both emphasized by earlier authors) were widely variable and subject to evo- lutionary convergence within Nodilittorina. They recog- nized three subgenera: Nodilittorina s.s. (the great ma- jority of species), Tectininus (for N. antonii (Philippi)), and Liralittorina (for N. striata (King & Broderip), later removed to Littorina, see Reid, 1989a). They also raised Fossarilittorina to full generic status. This unfamiliar ar- rangement was not, at first, widely followed. However, Reid (1986), in a monograph of Littoraria, added addi- tional anatomical data on many Nodilittorina species, be- sides new characters of spermatozoa and pallial oviduct, and presented a preliminary cladistic analysis of the fam- ily. This almost entirely supported the new scheme (al- though antonii was removed to Echininus). The most recent revision of the classification of Lit- torinidae was by Reid (1989a), based on a cladistic anal- ysis of a wide range of morphological characters from examples of all known subgeneric groups. In this new scheme 40 species were placed in Nodilittorina, but a precise definition of this genus remained elusive since the only synapomorphy discovered was a dubious character of head pigmentation that was not uniquely derived. Sub- genera within Nodilittorina were also not clearly defined; three were recognized, Fossarilittorina, Echinolittorina, and Nodilittorina s.s., but lacked strong synapomorphies. In the past decade this generic classification of the Lit- torinidae has become widely accepted (see reviews by McQuaid, 1996a; Reid, 1996; Reid & Geller, 1997). Diagnosis: Shell: conical to globular; occasionally with pseudo-umbilicus; often an eroded parietal area; adult sculpture of spiral grooves, with or without spiral mi- crostriae, sometimes with granular or nodular sculpture, or sometimes becoming entirely smooth; mineralogy ara- gonitic, of crossed-lamellar structure with fine outer layer. Head-foot: tentacles pale with 2—3 longitudinal black stripes, or all black. Male: prostate gland open; anterior vas deferens open; penial vas deferens usually open; usu- ally a single mamilliform gland and a penial glandular disc, borne together on a projection of penial base, but either or both may be absent. Paraspermatozoa: usually with rod-pieces. Female: copulatory bursa in relatively posterior or anterior position; egg groove of pallial ovi- duct coiled in a single spiral of one whorl through albu- men gland, sometimes an additional loop in capsule gland and/or in jelly gland. Spawn and development: pelagic capsules, usually cupola-shaped with concentric rings on upper side, containing single ova; development plankto- trophic. Radula: rachidian tooth longer than wide, some- times considerably narrowed, 3 cusps, central one elon- gate; 4 cusps on each of lateral and inner marginal (oc- casionally reduced), but one major cusp on each is elon- gate; outer marginal with narrowed neck and projection on outer side of base, 4-10 cusps (modified from Reid, 1989a). Remarks: The phylogenetic analysis of Reid (1989a) was based on a morphological survey of a large number of littorinid species, including 35 assigned to Nodilittorina, but in the cladistic analysis these were represented by a single example from each of the supposed subgeneric groups, together with a few species of uncertain relation- ships. The genus Nodilittorina was represented by N. (Fossarilittorina) meleagris, N. (? Fossarilittorina) mo- desta, N. (Echinolittorina) dilatata (d’Orbigny), and N. Page 90 The Veliger, Vol. 45, No. 2 (Nodilittorina) pyramidalis. In the resulting cladogram, the genus appeared as a monophyletic group, but the only synapomorphy was coloration of the head, considered to be a weak character since it was shared with two unre- lated groups. It appeared therefore that most of the char- acter states used in the diagnosis (see above) were ple- siomorphic and not indicative of close relationship. Three subgenera were tentatively distinguished, based on ab- sence of penial glands (Fossarilittorina) and position of the copulatory bursa (at the posterior end of the straight section of the pallial oviduct in Echinolittorina, anterior in Nodilittorina s.s.), but again these character states were not unique or even (in the case of the posterior bursa) apomorphic. There was a suggestion of some correlation with biogeography, since Fossarilittorina and Echinolit- torina were restricted to the Atlantic and eastern Pacific regions. There is also some limited support from mito- chondrial gene sequence analysis; six Nodilittorina spe- cies were included as an outgroup in a study of Littorina (Reid et al., 1996), and the four members of Echinolit- torina (all from the Atlantic) formed a clade. An early molecular study of Central American littorinids (Jones, 1972), based on allozymes and myoglobin, failed to unite seven species of Nodilittorina, but also did not demon- strate the integrity of five species of the undoubtedly monophyletic Littoraria (Reid, 1999a, b) and can there- fore be disregarded. Another question relating to the phylogeny and defi- nition of Nodilittorina is the correct classification of the Atlantic species Littorina (Liralittorina) striata. This has been placed in Nodilittorina by some authors (Rosewater, 1981; Bandel & Kadolsky, 1982), although it appears as the basal extant species of Liftorina (sister-group to No- dilittorina) in a species-level cladogram of that genus (Reid, 1996). Molecular evidence from both mitochon- drial (Reid et al., 1996) and nuclear gene sequences (Win- nepenninckx et al., 1998), and also from radular muscle proteins (Medeiros et al., 1998), support placement in Lit- torina. Nevertheless, many uncertainties remain about the classification and phylogeny of this group. The genus is still not adequately defined by any unique morphological synapomorphy, and it may prove to be a paraphyletic or polyphyletic assemblage consisting of those littorinine species that do not fall into any of the other more well- defined genera (1.e., Melarhaphe, Peasiella, Mainwarin- gia, Tectarius, Cenchritis, Littorina). A particular con- cern is that none of the recent morphological or molecular analyses has included members of a group of Nodilitto- rina species from the southern oceans (considered part of subgenus Nodilittorina by Bandel & Kadolsky, 1982, and by Reid, 1989a; but here referred to the subgenus Aus- trolittorina, see Remarks on N. fernandezensis) that show some resemblances to Lifforina striata (e.g., shape of pal- lial oviduct) as well as to typical Nodilittorina members (e.g., penis and paraspermatozoa). Fossarilittorina too is a problematic group, with the Atlantic N. meleagris as type species (Rosewater, 1981). This is characterized by an unusual penis with closed sperm duct and no large glands, and its possible relationship to the eastern Pacific N. modesta and N. porcata groups remains unclear. At- tempts have been made (Reid, unpublished) to include all recognized Nodilittorina species in a morphological phy- logenetic analysis, but the results show an almost com- plete absence of structure, owing to relatively few infor- mative characters and widespread homoplasy. These problems may only be resolved by means of new molec- ular studies, since the available morphological evidence is inadequate. Meanwhile, the definition of Nodilittorina proposed by Reid (1989a) is followed here, although it is considered premature to assign the eastern Pacific species to any of the three constituent subgenera. The subgenus Austrolit- torina 1s, however, used here for N. fernandezensis, to emphasize its closer relationship to N. unifasciata, the Australian type species of the subgenus (Rosewater, 1970), than to all the other eastern Pacific species. Un- fortunately, the continuing uncertainty surrounding the phylogenetic relationships of Nodilittorina may, when re- solved, have nomenclatural consequences. The type spe- cies of Nodilittorina was designated by Abbott (1954) as N. pyramidalis, an endemic Australian species which is in several respects atypical. Although its shell is nodulose (like such “typical”? species as N. dilatata and N. tro- choides), its pallial oviduct is identical to that of N. (Aus- trolittorina) unifasciata, and its penis has a papillose fil- ament unique in the genus. It is possible that N. pyram- idalis may prove to be a member of the Austrolittorina group, so that Austrolittorina may fall in the synonymy of Nodilittorina. If, in addition, it were to be discovered that the Austrolittorina group does not form a clade to- gether with the other Nodilittorina species, the genus No- dilittorina (with Austrolittorina in synonymy) would have to be employed in a more restricted sense than at present. In the following systematic account, the Nodilittorina species of the eastern Pacific are divided into three in- formal groups: six species in the N. porcata group, two in the N. modesta group, and six in the N. aspera group. This is convenient since the groups are easy to recognize morphologically. Furthermore, in each case, the included species are sufficiently similar that each group may well prove to be monophyletic. The relationships of the re- maining four species are unclear and they are dealt with last. The Nodilittorina porcata Group Considerable confusion has surrounded the identifica- tion and nomenclature of a group consisting of the fol- lowing six species: N. atrata, N. porcata, N. santelenae, N. fuscolineata, N. parcipicta, and N. albicarinata. All are small (less than 7.6 mm) and share a number of shell D. G. Reid, 2002 features that are unusual in the genus Nodilittorina. Most striking is their protean plasticity of shell shape, sculp- ture, and coloration, which in some of these species equals that of any other littorinids. Once the species have been separated by anatomical criteria, it becomes clear that each shows a parallel and analogous range of shell variation. Thus shell shape ranges from globular to rather tall-spired and, while most show a perforated pseudo-um- bilicus (or at least a crescentic area adjacent to the col- umella), this is closed or absent in juveniles and some adults. Shell sculpture consists of spiral microstriae, sometimes sufficiently regular and widely-spaced to be termed primary spiral grooves. Whereas some shells de- velop no further sculpture and therefore appear macro- scopically smooth, others produce strong spiral ribs which, particularly at the periphery, may become flanged keels or carinae. Shell coloration is highly variable in all these species. Most can occur in an unpigmented white form, but more often develop a conspicuous pattern of brown or black axial stripes, spots, and spiral bands. In the Discussion it is argued that this striking variability in shell characters may be largely under ecophenotypic con- trol. Certain anatomical characters are also shared by this group, including the absence of the penial glandular disc, peculiar twist to the end of the penial filament (slight or absent in two species), and flexure between straight and spiral portions of the pallial oviduct. These characters are likely synapomorphies and suggest that the group is a monophyletic one. They also share similar radulae, with pointed cusps; this, however, is characteristic of juvenile and small adult littorinids (see Reid, 1996, in Littorina) and may simply be an allometric effect of small size. Within the group, subjective similarities in shell, penes, and paraspermatozoa suggest two sub-groups, N. atrata, N. porcata, and N. santelenae, on one hand, and N. fus- colineata, N. parcipicta, and N. albicarinata, on the oth- er. Not surprisingly, this extreme intraspecific variation in shell shape has resulted in a confused taxonomy, at not only the specific but also the familial level. The earliest name is Littorina porcata Philippi, 1846, and this has continued to be widely applied to members of the group. In his catalogue of shells from Panama, C. B. Adams (1852a, b) described four species, of which only atrata was confidently placed in Littorina (then applied in a broad sense, including most members of the subfamily Littorininae); two of the remainder were doubtfully in- cluded, with the comment that they might be members of Narica (= Vanikoro, Vanikoroidae), while the fourth was doubtfully assigned to Adeorbis (Vitrinellidae). In fact, all are synonyms of Nodilittorina atrata, emphasizing its extreme variability. Succeeding authors were also uncer- tain about the familial assigment of these taxa and, on account of their usual possession of umbilicus and spiral carinae, often listed them as species of Fossar (H. & A. Adams, 1854) or Fossarus (A. Adams, 1855; Carpenter, Page 91 1857a, 1863, 1864a; Tryon, 1887; Turner, 1956; Keen, 1971; Abbott, 1974; Finet, 1985), a genus variously clas- sified as littorinid, as a monotypic cerithioidean family and, most recently, as a member of the Planaxidae (Houb- rick, 1990). In recognition of this resemblance to Fos- sarus, Rosewater (1981) introduced Fossarilittorina as a subgenus of Liftorina and included five names that have been applied to members of the N. porcata group (al- though the type species was the Atlantic N. meleagris). Bartsch & Rehder (1939) described a new taxon as a member of the littorinid genus Peasiella (see Reid, 1989b; Reid & Mak, 1998), misled by the trochoidal shell shape. The most widespread of the group, N. atrata, has also been misidentified as a species now assigned to /s- elica (Pyramidellidae) and possibly as another now rec- ognized as a Tricolia (Turbinidae) (see synonymy of WN. atrata). In describing the new species albicarinata, Mc- Lean (1970) tentatively referred it to Littorina, and called for a detailed examination of the relationships of this east- ern Pacific group with Fossarus. Their classifications as littorinids was finally established beyond doubt when Reid (1989a) described the general anatomy of N. porcata s.l. in a review of littorinid phylogeny, and placed it in the genus Nodilittorina. At the specific level, members of the N. porcata group have been neglected by systematists. Only the species porcata was included in the nineteenth century mono- graphs of Littorina (Philippi, 1847; Reeve, 1857; Wein- kauff, 1882; Tryon, 1887) and none was mentioned in von Martens’ (1900) monograph of Littorina in Central America. Carpenter (1863) reviewed the taxa of C. B. Adams (1852a, b) from Panama, but reduced only one to synonymy. New taxa were added by A. Adams (1855), Carpenter (1864), Bartsch & Rehder (1939), and McLean (1970), and two additional species are described here. Keen (1971) figured ‘‘Peasiella” roosevelti and ‘‘Litto- rina” albicarinata, but other names in the group were simply listed uncritically as species of Fossarus. In Rose- water’s (1970) list of worldwide Littorinidae, the only name that might apply to this group was Littorina (Me- larhaphe) umbilicata (this is doubtful; see Taxonomic History of N. atrata). In the only other recent attempt to list the species of Littorinidae, Reid (1989a) gave N. por- cata (which included WN. atrata) and N. albicarinata. Else- where in the systematic literature the members of the N. porcata group have appeared only in faunistic lists. No critical revision has previously been attempted for these taxa and is only possible now owing to the avail- ability of anatomical material. It was the diagnostic penial differences that provided the first intimation that six dis- tinct species are involved. These differences in shape are subtle, but the interpretation is supported by their corre- lations with shell traits. Most importantly, each of the species is not only sympatric but also syntopic (i.e., oc- curring together in the same microhabitat) with at least one other in the group and, in such cases, the diagnostic Page 92 penial and shell traits are maintained. For those pairs not known to occur sympatrically, morphological differences are of the same order and, taken together with widely separated geographical ranges, support their specific sta- tus. Characters of the oviduct and radula are not generally useful for discrimination. Identification of these species still poses a challenge, and the most useful features are summarized in Table 1. Since there is only partial overlap of their geographical ranges, and the number of sympatric taxa is not known to exceed three, information about geographical origin of samples is useful. If this is known, examination of shells is almost always adequate for identification. However, the critical characters are not usually the most obvious fea- tures such as shell outline, smooth or carinate sculpture, perforated or closed pseudo-umbilicus, or white as op- posed to patterned surface. Instead, the details of color pattern and of microsculptural striation are more signifi- cant (Table 1). Penial characters can be used to confirm identification of male specimens, but even here, occa- sional problems are encountered if penes are strongly contracted or contorted before fixation, or when mamil- liform penial glands are missing (a rare abnormality, seen in two of the approximately 100 males examined). In addition to their morphological similarity, the six members of the N. porcata group share some similarity in their ecology. Whereas most species of Nodilittorina are typically found among the superficially bare rocks and crevices of the littoral fringe, extending down to the up- permost eulittoral, those of the N. porcata group are gen- erally to be found at a lower level, among barnacles, in crevices, and in shallow pools, in the mid to upper eulit- toral zone. Whether this is simply a reflection of their small size, or of some physiological or dietary character- istic, is unknown. Nodilittorina atrata (C. B. Adams, 1852) (Figures 1A—I, 3A—G, 4A, FE G, H, 5A, 6) Littorina atrata C. B. Adams, 1852a:395—396, 537 (Panama; lectotype (Turner, 1956) MCZ 186444, seen, Turner, 1956:pl. 9, fig. 5, Figure 1E herein; approx. 200 para- lectotypes MCZ 186445, seen; 26 paralectotypes BMNH 1865.11.22.92, seen; 9 paralectotypes BMNH 1865.11.24.181, seen). C. B. Adams, 1852b:171-172, 313. Carpenter, 1857a:273. Carpenter, 1863:352. Ver- meij, 1973:324. Carpenter, 1857a:326. Fossarus atratus—Carpenter, 1863:352. Tryon, 1887:272, pl. 52, fig. 10. Hertlein & Strong, 1939:371. Morrison, 1946:10—11. Turner, 1956:33, pl. 9, fig. 5. Keen, 1971: 454, fig. 772. Fossarina atrata—Carpenter, 1864b:550. Littorina (Fossarilittorina) atrata—Rosewater, 1981:30. Fi- net, 1985:13. Littorina (?) excavata C. B. Adams, 1852a:396, 537 (Pan- ama; holotype MCZ 186422, seen, Turner, 1956:pl. 13, Litorina atrata The Veliger, Vol. 45, No. 2 fig. 2). C. B. Adams, 1852b:172, 313. Carpenter, 1857a: DiS: Fossar excavatus—H. & A. Adams, 1854:320. Fossarus excavatus—Carpenter, 1857a:326. Carpenter, 1863:352. Pilsbry & Lowe, 1932:124. Turner, 1956:47, pl. 13, fig. 2. Keen, 1971:454. Littorina (Fossarilittorina) excavata—Rosewater, 1981:30. Finet, 1985:13. Littorina (?) foveata C. B. Adams, 1852a:397, 537 (Panama; lectotype (Turner, 1956) MCZ 186454, seen, Turner, 1956:pl. 9, fig. 6; 1 paralectotype lost). C. B. Adams, 1852b:173, 313. Carpenter, 1857a:273. Fossar foveatus—H. & A. Adams, 1854:320. Fossarus foveatus—Carpenter, 1857a:326. Carpenter, 1863: 352. Turner, 1956:50—51, pl. 9, fig. 6. Keen, 1971:454. Adeorbis (?) abjecta C. B. Adams, 1852a:407—408, 539 (Panama; lectotype (Turner, 1956) MCZ 186338, seen, Turner, 1956:pl. 9, fig. 7; 15 paralectotypes MCZ 186339, seen). C. B. Adams, 1852b:183—184, 315. Car- penter, 1857a:273. Turner, 1956:27, pl. 9, fig. 7. Fossar abjectus—H. & A. Adams, 1854:320. Fossarus abjectus—Carpenter, 1857a:326. Carpenter, 1863: 354. Hertlein & Strong, 1955a:137. Keen, 1971:453. Fi- net, 1985:17. Lacuna abjecta—Pilsbry & Lowe, 1932:124. Fossar variegatus A. Adams, in H. & A. Adams, 1854:319— 320; 3:pl. 33, fig. 7a, b (operculum) (nomen nudum). Fossar variegatus A. Adams, 1855:187 (Eastern Seas [in error, here corrected to Panama]; 4 syntypes BMNH 1968821, seen). Fossarina variegata—Nevill, 1885:171. Littorina porcata—Nevill, 1885:138 (not Philippi, 1846). Nodilittorina (Nodilittorina) porcata—Reid, 1989a:100, fig. Sh (in part, includes N. porcata). Skoglund, 1992:15, 16, 33, 34 (in part, includes N. porcata). Fossarus angiostomus—Morrison, 1946:10 (not Littorina angiostoma C. B. Adams, 1852, which is an Jselica, Pyramidellidae; personal observation of lectotype MCZ 186442). Hertlein & Strong, 1955a:137 (not C. B. Ad- ams, 1852). Finet, 1985:17 (as F. angiostoma; not C. B. Adams, 1852). Littorina (Melarhaphe) ? angiostoma—Jones, 1972:2 (not C. B. Adams, 1852). Littorina angiostoma—Rosewater, 1980:7, figs. 7, 8 (radula) (not C. B. Adams, 1852). Littorina (Fossarilittorina) angiostoma—Rosewater, 1981: 30 (not C. B. Adams, 1852). Nodilittorina (Nodilittorina) angiostoma—Skoglund, 1992: 15. Kaiser, 1993:106. Kaiser, 1997:27. (All not Littorina angiostoma C. B. Adams, 1852). Nodilittorina angiostoma—Finet, 1994:18 (not Littorina an- giostoma C. B. Adams, 1852). ? Littorina (? Melarhaphe) umbilicata—Rosewater, 1970: 424 (not Littorina umbilicata d’Orbigny, 1840, which is a Tricolia, see Keen, 1971:358; personal observation of holotype in BMNH). ? Littorina umbilicata—Alamo & Valdivieso, 1987:26. Al- amo & Valdivieso, 1997:18. Paredes, Huaman, Cardoso, Vivar & Vera, 1999:22. (All not d’Orbigny, 1840). See also Synonymy and Taxonomic History of N. por- cata. Taxonomic history: The history of this species is one of considerable complexity, involving uncertain generic as- Page 93 DEG Reid y2 002 juosoid aseq jo uonoafoid uo ‘asie] Po}stM} ‘pojurod vULIvS aIYM YM UMOIG sok sok sok juasqe BIUIOJTPED JO J[NH ‘eruropyed eleg MS DIDULIDIIGID “NI quasaid SOUITOUIOS aseq 0} ApoorIp poyorne ‘asivy] poaistM) JOU 4uUNTG Sqit [][e uo sjods uMoq [[ews o1ed sok ou quosoid (OorxXayy) UBD -BOYOITAL 0} VOTPUIS ‘viusojeS eleg § yuosoid SOUITNOUIOS aseq 0} Ap}OeIIp poyorne ‘[feurs PoisiM} JOU ‘payurod Squi uO soysep suo] 10 Soul] UMOIQ YUM aed ou A[UO Ssqii Suo1s oIed juasoid Jopenogq § 0} IOpeales [q pyaidiosvd “NI Dypauyoosn{ ‘N yuosoid SOUITOUIOS quasaid SOUINOUIOS aseq 0} aseq jo ApoalIp poyoerne uonoofoid uo ‘]peurs ‘asiey Ajoyeropour Posimy posta} ‘pajurod Apysiys ‘peyooy 10 pajurod aseq pue oinjns je pureq aYyM YIM UMOIG squi [eseq uo sjods UIM ‘sadiys [erxe uy 10 Suljqiew yep ou sok orer = ATUO euULIes [essydiiod sok Soh quasqe juasoid nidg N ‘opens s s] sosedyyey juosqe aseq Jo uonsafoid uo ‘asivy Ajaye.1opoul poisim) ‘poqurod Axoydiiod dAoqge purq yoryq UJIM ‘aseq oO} o1nIns woly sodiys ay1yM pue yor[q proiq Sok sok sok juosoid s] sosedyyey ‘o00D [9P PIS] ‘n1ag N 0} Jopeaes [q oseq uo JuoUIs1d— pur[s wo} pruew— dy juowe,y— studg usaned UOWUILUOD JSOUI— WIOJ DIY [[e— WO} aeVULIeI— WLIO} YJOouUrS— snorpiquin-opnasd— Ileus osuvi jeorydeis0aH al IDUAIAJUDS “| pypoiod “Nl DIDAID “N Tojyov rey) ‘dnois pypo10d vuis0yIpoN IY) JO so1dads xis dy} JO UONRIYNUSpPI oy} IOJ s1oJOVIBYS [NJosn Jsour oy} Jo Areuruins T 91981 Page 94 The Veliger, Vol. 45, No. 2 signment, synonyms, misidentification, and confusion with other members of a complex of similar species. In the account of the shells of Panama in which C. B. Adams (1852a, b) first described this species, he introduced three additional taxa which prove to be its synonyms, a mea- sure of the great intraspecific variability of this species. Littorina atrata included largely black shells with small umbilicus, although he noted its variability in shape and sculpture. Littorina foveata was based upon patterned shells with a wide umbilicus, and L. excavata referred to the smooth, globular white form (as in Figure 1H), of which Adams had only a single specimen. These latter two were both only doubtfully assigned to Littorina, and Adams suggested that Narica (= Vanikoro) might be more suitable. The last taxon, Adeorbis abjecta, was based upon shells with a low, eroded spire; again the generic assignment was tentative; and Adams noted a re- semblance to ‘“‘Littorina’’ porcata, Carpenter (1863) placed it in the synonymy of “‘Fossarus’ atratus. For almost 100 years these names were scarcely mentioned in the literature, except in the reviews of Carpenter (1857a, 1863) and iconography of Tryon (1887), and there as species of Fossarus. During the middle part of the twentieth century, studies of West American mollusks increased, and these supposed Fossarus species appeared in several faunistic lists (Pilsbry & Lowe, 1932; Hertlein & Strong, 1939; Morrison, 1946). The types of C. B. Adams were figured by Turner (1956), but even Keen (1971) simply listed them, unfigured, as Fossarus species. That they were in fact littorinids was eventually recog- nized by Rosewater (in Jones, 1972; Rosewater, 1980, 1981), and Vermeij (1973), who used the genus Littorina, and confirmed by Reid (1989a), who used Nodilittorina. Another synonym is Fossar variegatus, an almost entirely neglected name. This was based on material in the Cum- ing Collection, but in his description A. Adams (1855) gave the incorrect locality ‘“‘Eastern Seas’’; the four syn- types are somewhat eroded, but are clearly examples of a form of N. atrata that is common in Central America, and could easily have been collected by Cuming during his travels in the region. Hitherto, no authors have discriminated among all six members of the N. porcata complex, and there has there- fore been much misidentification, although geographical distribution can sometimes be used to recognize the spe- cies intended. Since porcata Philippi, 1846 is the oldest name, it has been the most widely used in the past decade (following Reid, 1989a; see Skoglund, 1992; Kaiser, 1993, 1997; Finet, 1994). However, both N. atrata and N. porcata occur together in the Galapagos Islands, and so the names used in faunistic lists of Galapagos species (Stearns, 1893b; Hertlein & Strong, 1939, 1955a; Ver- meij, 1973; Kaiser, 1993, 1997; Finet, 1985, 1994) cannot be confidently assigned in the synonymies. To add to the confusion, the name angiostoma also appears frequently in the literature. This is a misidentification; Littorina an- giostoma C. B. Adams, 1852, is an /selica, belonging to the Pyramidellidae (figured by Turner, 1956:pl. 13, fig. 1). This name has been used mainly in works on the Galapagos fauna (Hertlein & Strong, 1955a; Finet, 1985, 1994; Kaiser, 1993, 1997), and these also list at least one other species (usually porcata or abjecta). It seems likely that angiostoma was used for shells of the white ecotype, and porcata for patterned shells. However, this distinction does not separate N. atrata s.s. and N. porcata s.s. in the Galapagos, so that again the synonymy cannot be re- solved. For convenience, in these doubtful cases, uses of the name atrata and its synonyms (including angiostoma non C. B. Adams) for Galapagos shells are listed above, while uses of porcata (and its synonym roosevelti) are given in the synonymy of N. porcata. Curiously, in his influential work on Indo-Pacific Lit- torinidae in which all species recognized worldwide were listed, Rosewater (1970) did not give any of the names discussed above. Instead, the older name Littorina um- bilicata appears, doubtfully assigned to the subgenus Me- larhaphe. This may have been intended to refer to some of the members of the N. porcata group, although the distribution given (‘Peru and Chili,” perhaps following Dall, 1909) is not correct (N. atrata and N. santelenae only just reach far northern Peru). If so, this is another misidentification, since Littorina umbilicata d’Orbigny, 1840, is in fact a species of Tricolia (Keen, 1971). The name also appears in several recent lists of Peruvian mol- lusks (Alamo & Valdivieso, 1987, 1997; Paredes et al., 1999), in which Tricolia umbilicata is listed separately, suggesting that “L. umbilicata’’ might indeed be intended for N. atrata and/or N. santelenae. Diagnosis: Shell small, globular to tall, smooth to cari- nate; coarse, irregular microstriae; usually a large, per- forated, pseudo-umbilicus; may be white, but common pattern is broad black or brown axial stripes from suture to base and broad band above periphery, on white ground. Penis with pointed and twisted filament tip, moderately large mamilliform gland on long projection of base, no ‘ glandular disc. Material examined: 73 lots (including 26 penes, 11 sperm samples, eight pallial oviducts, one egg capsule, five radulae). Shell (Figures 1A—-I): Mature shell height 2.1—7.5 mm. Shape variable; high turbinate to low-spired, globular or slightly patulous (H/B = 1.00—1.53; SH = 1.24-—2.21); spire whorls rounded, suture distinct; periphery of last whorl usually rounded, but may be marked by a rib or carina; solid. Columella straight, narrow, flared and flat- tened at base; pseudo-umbilicus usually large, perforated, outlined by sharp keel continuous with outer apertural lip, but sometimes only narrow imperforate crescentic area (pseudo-umbilicus narrow or absent in most juveniles). D. G. Reid, 2002 Sculpture variable; smoothest shells covered with coarse, rather irregular, spiral microstriae (rarely becoming ob- solete above periphery of last whorl); sometimes 5—16 indistinct ribs may develop on last whorl (peripheral rib and 2-3 on base are strongest); strongly sculptured shells with few sharp or carinate ribs, 2—3 on base, strongest rib at periphery, 1—7 above periphery (juveniles 2 on base, 1 at periphery, | at shoulder), entire surface with strong microstriae; periostracum occasionally produced into mi- nute bristles (to 100 4m) on basal and peripheral ribs of strongly sculptured shells. Protoconch 0.26—0.29 mm di- ameter. Color variable, may change abruptly; frequently entirely white externally (especially in smooth, globular shells), sometimes with irregular large blotches of black, fine brown speckles, or continuous dark brown band be- tween shoulder and periphery; most common color is striking black and white pattern, with broad, black or dark brown oblique axial stripes from suture to base, usually fused between shoulder and periphery to form irregular continuous dark band; rarely entirely black but for few white flames on base; columella and aperture usually pink-brown to dark purple-brown (even in white shells), with anterior and often posterior unpigmented band. Animal: Head and sides of foot grey to black; 2 black lines along tentacle, seldom meeting at tip; usually a nar- row white band across snout. Opercular ratio 0.41—0.47. Penis (Figures 3A—G): filament tip pointed and twisted; sperm groove with a kink, distal portion shallower, ex- tending to filament tip; single mamilliform penial gland on long lateral appendage at 0.4—0.6 total penial length (mamuilliform gland absent in one specimen); glandular disc absent; base not pigmented. Euspermatozoa 79-107 wm; paraspermatozoa (Figures 4G, H) oval, 14—26 wm; rod-pieces single (rarely two), filling cell or projecting at one end (rarely both ends), 14—21 wm, blunt or slightly rounded at ends, parallel-sided or slightly tapering; gran- ules large, spherical, distinct. Pallial oviduct (Figure 4A) with flexure and constriction between spiral and straight sections; copulatory bursa opening at anterior end of straight section, extending back to start of spiral portion. Spawn (Figure 4F) a pelagic cupola-shaped capsule 160 yum diameter, sculptured with four concentric rings, con- taining single ovum 40 pm diameter; protoconch indi- cates planktotrophic development. Radula (Figure 5A): Relative radular length 2.1—3.5. Rachidian: length/width 1.11—1.68; major cusp pointed and elongate leaf-shaped. Lateral and inner marginal: ma- jor cusps pointed or slightly rounded. Outer marginal: 5—7 cusps. Habitat: Among uppermost oysters and barnacles; in crevices and shallow pools in mid to upper eulittoral; on sandstone, basalt, concrete; sheltered to exposed coasts, sometimes in silty, mangrove-fringed channels; often abundant. Page 95 Range (Figure 6): El Salvador to northern Peru, Isla del Coco, Galapagos Islands. Range limits: Los Cobanos, Sonsonate, El Salvador (LACM 73-56, 3 specimens); Isla Zacatillo, Golfo de Fonseca, El Salvador (LACM 73-57): Coyolita, Honduras (USNM 749644); San Juan del Sur, Nicaragua (USNM 60677); Puerto Utria, Choco, Colom- bia (LACM 34-106.20, 1 specimen); Same, Esmeraldas, Ecuador (BMNH 2001151); El Rubio and Punta Mero, Tumbes, Peru (LACM 72-85, | specimen); Isla del Coco (USNM 130103; KLK); Galapagos Islands (Isla Santiago, USNM 807236; Isla Floreana, personal observation; Isla San Cristobal, BMNH 20001152; Isla Bartolomé, BMNH 20001153; Isla Santa Cruz, BMNH 20001154). The re- cord from Los Cobanos is an isolated patch of hard sub- strate on a largely sedimentary coast, the Central Amer- ican Gap (Glynn & Ault, 2000). The species is common in the Golfo de Fonseca, Isla del Coco, the Galapagos Islands and elsewhere, but only single specimens have been seen from Colombia and Peru. Remarks: The shell of N. atrata is among the most var- iable of all littorinid species, ranging from globular to tall, umbilicate to imperforate, smooth to carinate, white to black-patterned. There is no apparent geographical com- ponent to this variation; for example, the distinctive smooth, white, globular shells are recorded from the Ga- lapagos Islands, Ecuador, Panama, and Costa Rica. How- ever, it is notable that of the available museum collec- tions, most individual samples encompass a relatively re- stricted range of shell variation, and extreme variability in color or sculpture from a single locality is unusual. Personal collections suggest that there may be a correla- tion with microhabitat, though this requires further inves- tigation. For example, at Punta Chocolatera (Peninsula Santa Elena, Guayas, Ecuador) a sample from crevices among barnacles in the upper eulittoral comprised ribbed shells, mostly with strong black patterning (BMNH 20001155, Figure 1F), whereas a sample from shallow pools on an open rock platform only 20 m distant com- prised only white, smooth, globular shells (BMNH 20001156, similar to Figure 1H). A similar, but less per- fect, correlation was observed nearby at Anconcito (BMNH 20001157, 20001158). In general, samples from lower tidal levels (mid eulittoral) and from pools appear to be more smooth and sometimes white in color, whereas those from among barnacles are more strongly ribbed or carinate. Shell color may change abruptly on a single in- dividual, for example from black patterned to entirely white or vice versa (Figure 1G). Sculpture does not show similarly sudden change, although relatively smooth shells sometimes develop low ribs on the final part of the last whorl. A possible interpretation of these observations is that the species are susceptible to ecophenotypic effects on shell form and coloration (see Discussion). This is the most widely distributed of the six species in the N. porcata group. It is sympatric with N. fuscoli- Page 96 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 neata from El Salvador to Ecuador, with N. porcata in the Galapagos Islands, and with N. santelenae in southern Ecuador and northern Peru. In each case, these can be found in the same microhabit as N. atrata, although some differences in habitat range are likely (see Remarks on all three). These four potentially sympatric species can be distinguished by penial shape but, owing to the great range of variation, identification from shells alone is sometimes difficult (Table 1). In the Galapagos Islands both NV. atrata and N. porcata may be white; the latter usually shows fine, regular microstriae, an angled periph- ery, and a strong peripheral and two basal ribs; in N. atrata the microstriae are coarser and more irregular, the periphery rounded and, if ribs are present at all, they are uniformly developed over the whorl. Patterned shells are more distinctive; in N. atrata, the common black and white pattern of broad axial stripes from suture to base and broad dark band above the periphery is diagnostic; dark shells of N. porcata are usually marbled or finely striped, with brown spots on the basal ribs and often a pale basal band. In southern Ecuador and northern Peru, shell coloration again usually distinguishes N. atrata from sympatric N. santelenae; the latter is commonly brown or black with a white band on the base and often a second at the suture, or (in the smooth algal-dwelling form) mot- tled yellow-brown with strong brown and white spots at shoulder and periphery. The shell of N. fuscolineata is smaller, more delicate, with markedly rounded whorls and regular ribs bearing a pattern of dark lines or dashes. Nodilittorina porcata (Philippi, 1846) (Figures 1J—Q, 3H-O, 4B, I, 5B, 6, 22E) Littorina porcata Philippi, 1846a:139 (ad insulas Gallapagos [Galapagos Islands, Ecuador]; lectotype (here designat- ed, 6.1 X 5.0 mm) BMNH 1968218/1, seen, Philippi, 1847:3, Litorina pl. 6, fig. 14, Figure 1J herein; 1 par- alectotype BMNH 1968218/2, seen; 2 probable paralec- totypes BMNH 1998193, seen). Carpenter, 1857a:186. Reeve, 1857:sp. 89, pl. 16, fig. 89. Stearns, 1893b:444. Litorina porcata—Philippi, 1847:3:14, Litorina pl. 6, fig. Page 97 14. Carpenter, 1857a:326, 360. Weinkauff, 1882:78—79, pl. 10, fig. 12. Weinkauff, 1883:215. Littorina (Littorina) porcata—Tryon, 1887:242, pl. 41, fig. 10. Fossarus porcatus—Keen, 1971:454, fig. 780. Littorina (Fossarilittorina) porcata—Rosewater, 1981:30. Finet, 1985:13. Nodilittorina (Nodilittorina) porcata—Reid, 1989a:100 (in part, includes N. atrata). Reid, 1989b:53. Skoglund, 1992:15, 16, 33, 34 (in part, includes N. atrata). Kaiser, 1993:106. Kaiser, 1997:27. Nodilittorina porcata—Finet, 1994:18 (in part, includes N. atrata). Peasiella roosevelti Bartsch & Rehder, 1939:8—9, pl. 2, figs. 1-3 (Sulivan [Sullivan] Bay, James Island [Isla Santi- ago], Galapagos; holotype USNM 472575, seen, Figure IN herein). Keen, 1971:367, fig. 191. Finet, 1985:13. See also Synonymy and Taxonomic History of N. atra- ta. Taxonomic history: The types of Littorina porcata are large and white, with variably developed ribs on the last whorl. In contrast, Peasiella roosevelti was based on a single, small, darkly patterned shell with strong peripheral keel. Surprisingly, in view of the longstanding assignment of other members of the N. porcata group to the genus Fossarus, Philippi (1846a) immediately classified his spe- cies as a member of Littorina, and it was subsequently included in several monographs of the genus (Philippi, 1847; Reeve, 1857; Weinkauff, 1882; Tryon, 1887); only Keen (1971) referred it to Fossarus. The trochoidal shape and umbilicus of the form described by Bartsch & Rehder (1939) are indeed reminiscent of the littorinid genus Peasiella, but that has a multispiral operculum (Reid, 1989b; Reid & Mak, 1998), a feature missing from the type, which was inhabited by a pagurid crab. Since por- cata is the oldest name in the N. porcata group, it has been frequently misapplied to the more widespread N. atrata. These two very similar species occur together on the Galapagos Islands, and previous authors working on the fauna have not distinguished them, so that synony- Figure 1. Shells of Nodilittorina porcata group: N. atrata (A-I), N. porcata (J—Q), and N. santelenae Reid, sp. nov. (R—X). A. Isla Pedro Gonzalez, Panama (USNM 587820). B. Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001159). C. Punta Pitt, Isla San Cristobal, Galapagos Islands (BMNH 20001152). D. Baltra Channel, Isla Santa Cruz, Galapagos Islands (BMNH 20001160). E. Lectotype of Littorina atrata C. B. Adams, 1852; Panama (MCZ 186444). F Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001155). G. Punta Egas, Isla Santiago, Galapagos Islands (USNM 807236). H. Montezuma, Costa Rica (USNM 664373). I. Muisne, Es- meraldas, Ecuador (BMNH 20001161). J. Lectotype of Littorina porcata Philippi, 1846; Galapagos Islands (BMNH 1968218/1). K. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (KLK). L, M, O-Q. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (L, BMNH 20001167; M, Q, BMNH 20001164; O, RP BMNH 20001168). N. Holotype of Peasiella roosevelti Bartsch & Rehder, 1939; Bahia Sullivan, Isla Santiago, Galapagos Islands (USNM 472575). R. Holotype of N. santelenae Reid, sp. nov.; Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000309). S, T. Paratypes of N. santelenae Reid, sp. noy.; Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000310). U. Salinas, Guayas, Ecuador (USNM 368112). V. Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001171). W, X. Anconcito, Guayas, Ecuador (BMNH 20001170). Scale bar = 2 mm. Page 98 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 Page 99 mies cannot be accurately compiled (see Synonymy and Taxonomic History of N. atrata). Diagnosis: Shell small, globular to turbinate; peripheral rib or carina, smooth or ribbed above; fine, regular mi- crostriae; large, perforated pseudo-umbilicus; often white; if patterned, then dark marbling or fine stripes above pe- riphery, spots on base. Penis with pointed or hooked, twisted filament tip, moderately large mamilliform gland closely attached to base, no glandular disc. Material examined: 30 lots (including 19 penes, | sperm sample, 2 pallial oviducts, 3 radulae). Shell (Figures 1J—Q, 22E): Mature shell height 1.9-6.1 mm. Shape variable; turbinate to low-spired and globular (H/B = 1.04—1.26, SH = 1.29—1.83); spire whorls round- ed, with distinct suture, often appearing turreted (owing to shoulder angulation and strong peripheral rib just above suture); last whorl usually with angulate periphery marked by strong rib or carina, sometimes rounded but still with peripheral rib; solid. Columella straight, narrow, flared, and flattened at base; pseudo-umbilicus large, per- forated (narrow or imperforate in juveniles), outlined by sharp keel continuous with outer apertural lip. Sculpture variable; usually sharp or carinate peripheral rib and 2 basal ribs; smooth above periphery or with 1—6 rounded ribs developing on last whorl; occasionally all but pe- ripheral rib become obsolete; fine, regular spiral micros- triae usually present over entire surface (Figure 22E), but globular shells lacking ribs may be microscopically smooth; periostracum occasionally produced into fine bristles (to 200 xm; Figure 22E) on basal and peripheral ribs. Protoconch not seen. Color variable, may change abruptly; white or grey with brown to black oblique or wavy axial stripes, or fine marbling or irregular marks; base with brown spots on ribs, and often a pale spiral band on rib anterior to periphery; color pattern may be- come paler or disappear toward end of last whorl; shells may appear entirely white, although spire usually shows dark pattern unless heavily eroded; aperture dark brown or orange-brown, with anterior (sometimes also posterior) unpigmented band, columella brown. Animal: Head and sides of foot black; two thick black lines along tentacle, usually meeting at tip. Opercular ra- tio 0.42—0.53. Penis (Figures 3H—O): filament tip pointed and twisted, often giving hooked appearance; sperm groove with a kink, distal portion shallower, extending to filament tip; single mamilliform penial gland closely at- tached to base at 0.2—0.4 total penial length; glandular disc absent; base often slightly pigmented. Euspermato- zoa length unknown; paraspermatozoa (Figure 41) oval; rod-pieces single (rarely two), projecting at one or both ends, 11-19 wm, blunt, slightly tapering; granules large, spherical, distinct. Pallial oviduct (Figure 4B) with marked flexure and constriction between spiral and straight sections; copulatory bursa opening at anterior end of straight section, extending back to start of spiral por- tion. Spawn and development not observed. Radula (Figure 5B): Relative radular length 1.3-1.8. Rachidian: length/width 0.94—1.27; major cusp pointed and elongate leaf-shaped. Lateral and inner marginal: ma- jor cusps pointed. Outer marginal: 6—7 cusps. Habitat: In pits and shallow pools on basalt rocks and rock platforms, also concrete; upper eulittoral, sheltered to semi-exposed coasts; often abundant. In the Galapagos, N. porcata has also been reported from mangroves (Hedgpeth, 1969; Kay, 1991), but whether this refers to this species, N. atrata or both, is unknown. Range (Figure 6): Galapagos Islands only. Records from islands of Santa Cruz (BMNH 20001164), San Cristobal (BMNH 20001165), Bartolomé (BMNH 20001166), San- tiago (USNM 807236), Fernandina (LACM 72-196), Is- abela (LACM 33-163, 34-276), Baltra (LACM 66-206), and Genovesa (LACM 33-174). Remarks: This species is highly variable in shape, sculp- ture, and coloration. The two named taxa represent ex- tremes of the range of variation; the types of Littorina porcata are large, smooth or ribbed, and white, whereas the type of Peasiella roosevelti is small, sharply keeled, and darkly patterned. However, there seems no doubt that these are conspecific. Sculpture above the periphery varies from smooth to ribbed within some microsympatric Figure 2. Shells of Nodilittorina porcata group (continued): N. fuscolineata Reid, sp. nov. (A-E), N. parcipicta (F—M), and WN. albicarinata (N-W). A. Holotype of N. fuscolineata Reid, sp. nov.; Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 19990422). B. Isla San Pedrito, Costa Rica (LACM 72-22). C. Punta Penca, Guanacaste, Costa Rica (LACM 72-38). D, E. Isla Alcatraz, Costa Rica (LACM 72-46; two views). E Mazatlan, Sinaloa, Mexico (BMNH 20001177). G. Boca de Tomatlan, Jalisco, Mexico (BMNH 20001178). H, I, K. 7 km NE of San José del Cabo, Baja California Sur, Mexico (BMNH 20001179). J. Playa de los Muertos, Puerto Vallarta, Jalisco, Mexico (BMNH 20001180). L. Lectotype of Fossarus parcipictus Carpenter, 1864; Cabo San Lucas, Baja California Sur, Mexico (USNM 4060). M. Topolobampo, Sinaloa, Mexico (BMNH 20001176). N, P—R. Balandra, Baja California Sur, Mexico (BMNH 20001182). O. Holotype of Littorina albicarinata McLean, 1970; El Requeson, Bahia Concepcion, Baja California Sur, Mexico (LACM 1399). S. Puerto Lobos, Sonora, Mexico (USNM 862206). T. Playa Coromuel, Baja California Sur, Mexico (BNMH 20001186). U—W. Bahia Agua Verde, Baja California Sur, Mexico (USNM 264989). Scale bars A-E = 1 mm; F—W = 2 mm. Page 100 The Veliger! Vol, 45; Now D. G. Reid, 2002 collections, and ribbed specimens usually show smooth spires. Spire height too varies substantially within single samples. The variation in shell color is peculiar, since available samples are either white or darkly patterned, and not a mixture of both. Samples collected from the same locality in different years can differ strikingly in coloration; for example, shells from the precise location of basalt rocks beside the dock of the Charles Darwin Research Station in Academy Bay, Santa Cruz Island, were white (and smooth) in collections made in 1988 and 1989, but brown (and ribbed) in 1998 (personal obser- vation; BMNH 20001164, 20001167; CDRS). Close ex- amination of white shells with well preserved spires shows that the early whorls are in fact brown. Further- more, adults with predominantly brown shells can be found in which the coloration abruply becomes pale or white on the last whorl (Figure 1M). As in some other members of the N. porcata group, these observations sug- gest that shell color (and perhaps also sculpture) may be influenced by ecophenotypic effects (see Discussion). In museum collections from the Galapagos Islands, this species is often mixed with the closely similar N. atrata, and the two are syntopic in the habitats described above (personal observation). Nevertheless, there is probably some microhabitat or behavioral segregation between them, since in samples from Academy Bay, Santa Cruz Island, brown shells of N. porcata were frequently over- grown with a fine filamentous alga, whereas white shells of N. atrata from the same shores were not. The discrim- ination of these two species is discussed in the Remarks on N. atrata. Page 101 Nodilittorina santelenae Reid, sp. nov. (Figures 1R—X, 3P—U, 4C, J, K, 5C, 6) Etymology: Name derived from the type locality on the Peninsula Santa Elena, Ecuador. Types (Figure 1R): Holotype BMNH 20000309. 19 par- atypes BMNH 20000310 (Figures 1S, T); 100 paratypes in alcohol BMNH 20000311, 4 paratypes USNM 894294. Type locality: Punta Carnero, Peninsula Santa Elena, Guayas Province, Ecuador. Taxonomic history: In ANSP there is a sample of six shells of this species collected by C. E. White in Ecuador, bearing the name Lacuna guayaquilensis Bartsch (ANSP 144844); the name was apparently never published by Bartsch. Fossarus guayaquilensis Bartsch, 1928, is a dif- ferent taxon, a true member of the genus Fossarus (Bartsch, 1928). In some lists of Peruvian mollusks there appears the name Littorina umbilicata, without locality (Dall, 1909; Alamo & Valdivieso, 1987, 1997; Paredes et al., 1999; also world list of Littorinidae in Rosewater, 1970). This is a misidentification (see Taxonomic History of N. atrata), but might possibly be intended for the pre- sent species (perhaps also including WN. atrata). Diagnosis: Shell small, narrowly turbinate; smooth with impressed lines, or with low ribs and microstriae; pseudo- umbilicus small; usually imperforate; commonly brown with basal and sutural white band. Penis with slightly pointed, twisted filament tip, small mamilliform gland on short projection of base, no glandular disc. Figure 3. Penes of Nodilittorina porcata group: N. atrata (A-G), N. porcata (H—O), N. santelenae Reid, sp. nov. (P-U), N. albicarinata (V, DD—HH), N. parcipicta (W—CC), N. fuscolineata Reid, sp. nov. (II). A, B. Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001159; shell H = 3.9 mm, 3.7 mm). C. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001162; shell H = 2.9 mm). D. Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001156; shell H = 2.9 mm). E, FE Puerto Ayora, Isla Santa Cruz, Galapagos Islands (BMNH 20001163; shell H = 4.2 mm, 3.5 mm). G. Baltra Channel, Isla Santa Cruz, Galapagos Islands (BMNH 20001160; shell H = 4.5 mm). H—N. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (H, K, BMNH 20001169, shell H = 2.7 mm, 3.1 mm; I, J, BMNH 20001168, shell H = 3.2 mm, 3.3 mm; L, BMNH 20001164, shell H = 3.9 mm; M, N, BMNH 20001167, shell H = 2.8 mm, 3.3 mm). O. Punta Pitt, Isla San Cristobal, Galapagos Islands (BMNH 20001165; shell H = 3.4 mm). P, Q, S, T. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000311; shell H = 3.2 mm, 4.0 mm, S, T, 3.9 mm; two views). R. Anconcito, Guayas, Ecuador (BMNH 20001170; shell H = 2.9 mm). U. Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001171; shell H = 2.5 mm). V, HH. Playa Coromuel, Baja California Sur, Mexico (V, BNMH 20001186, shell H = 3.4 mm; HH, BMNH 20001185, shell H = 3.6 mm). W. Playa Coromuel, Baja California Sur, Mexico (BNMH 20001174; shell H = 4.0 mm). X, Y. Bahia Santa Marfa, Baja California Sur, Mexico (BMNH 20001173; shell H = 3.8 mm, 4.1 mm). Z, AA, BB. Topolobampo, Sinaloa, Mexico (BMNH 20001176; shell H = 3.7 mm, 3.5 mm; Z, AA, two views). CC. Punta Telmo, Michoacan, Mexico (BMNH 20001181; shell H = 3.6 mm). DD—GG. Balandra, Baja California Sur, Mexico (BMNH 20001182; shell H = 4.7 mm, 5.0 mm; EE, FE two views, 3.7 mm). II. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 19990422, holotype of N. fuscolineata Reid, sp. nov.; shell H = 2.8 mm). Abbreviations and shading conventions: pg, mamilliform penial gland; ps, penial sperm groove (thick line); r, reservoir of mamilliform penial gland (visible by transparency); sg, subepithelial glandular tissue of penial gland (dotted line; usually visible by transparency); dashed line, cut base of penis; stipple in folds of penial base indicates black pigment. Scale bar = 1 mm. D3) BREW ae. me, N ° Z Ya) sa iS => i aoe oO = eee ao) a “| SYS fh eS |e Soa i) a (GO w0Ie GYEe. Ga \ | = [ Py: << al RR eae SLY ae ; <=. Y Ces D. G. Reid, 2002 Page 103 Material examined: 17 lots (including 9 penes, 4 sperm samples, 3 pallial oviducts, 4 radulae). Shell (Figures 1R—X): Mature shell height 1.7—5.6 mm. Shape narrowly to elongately turbinate (H/B = 1.13- 1.57, SH = 1.36—1.84); whorls moderately rounded, slightly angled at periphery, suture distinct. Columella narrow, slightly thickened and convex in center; pseudo- umbilicus usually only a narrow imperforate crescentic area, but sometimes small, perforated. Sculpture variable; smoothest shells have 7-17 impressed striae (more close- ly spaced posteriorly) above slight rib at periphery of last whorl, 6—9 striae or 2—3 indistinct ribs on base, no ad- ditional microstriae, but sculpture sometimes becomes in- distinct; sculptured shells show total of 4—12 low rounded or narrow ribs (of which peripheral rib and one to two above only rarely become carinate) on last whorl with spiral microstriae between. Protoconch 2.3 whorls, 0.28 mm diameter. Color variable; darkest shells dark brown to black, with narrow white line or broad band on base; usually with additional white band at suture; base some- times faintly spotted; paler shells cream with broad grey- brown or indistinctly mottled band between periphery and shoulder; smoothest shells pale yellow-brown with faint brown mottling throughout, and prominent alternating brown and white blotches at shoulder and periphery; ap- erture brown with anterior (and sometimes posterior) pale stripe, or yellow-brown with external pattern showing through in palest shells; columella purple-brown. Animal: Head black, rarely an unpigmented line across snout, two black lines along tentacle, not meeting at tip; sides of foot speckled black or grey. Opercular ratio 0.38— 0.43. Penis (Figures 3P—U): filament tip pointed and twisted, sometimes giving slightly hooked appearance; sperm groove with a kink, distal portion more open, ex- tending to filament tip; single very small mamilliform pe- nial gland on short, narrow projection of base at 0.3—0.5 total penial length; glandular disc absent; base sometimes slightly pigmented. Euspermatozoa 100—107 jm; paras- permatozoa (Figures 4J, K) oval; rod-pieces single (rarely two), usually projecting at one or both ends, or at least filling cell, 11-23 ym, oblong, parallel-sided, ends blunt or hollowed; granules large, spherical, distinct. Pallial oviduct (Figure 4C) with flexure and constriction between spiral and straight sections; copulatory bursa opening at anterior end of straight section, extending back to capsule gland. Spawn not observed; protoconch indicates plank- totrophic development. Radula (Figure 5C): Relative radular length 1.0—2.1. Rachidian: length/width 1.13—1.77; major cusp pointed and elongate leaf-shaped. Lateral and inner marginal: ma- jor cusps pointed or slightly rounded. Outer marginal: six cusps. Habitat: Among barnacles in mid to upper eulittoral, of- ten in empty tests; in shallow pools with fine filamentous green algae, on rock platform, upper eulittoral; on sand- stone and mudstone; semi-sheltered bays and wave-ex- posed headlands; usually abundant. Range (Figure 6): Southern Ecuador and northern Peru. Recorded from Peninsula Santa Elena, Guayas, Ecuador (Punta Carnero, BMNH 20000310; Anconcito, BMNH 20001170; Punta Chocolatera, BMNH 20001171; La Lib- ertad, LACM 66-116; Playas, LACM 70-13); El Rubio and Punta Mero, Tumbes, Peru (LACM 72-85); Talara, Piura, Peru (USNM 368553, 1 specimen); Paita, Piura, Peru (USNM 368579, 368580, 1 specimen each). Remarks: This species has a narrowly restricted range and is therefore seldom represented in museum collec- tions. In the field, it is microsympatric with N. atrata among barnacles, but extends lower on the shore, and is much more common than that species where they occur together (personal observation, Peninsula Santa Elena); juvenile N. paytensis can also be found commonly in this microhabitat. The habitat among filamentous algae in shallow pools is unusual for this genus, and here it was found abundantly with only very few N. atrata (personal Figure 4. Pallial oviducts (A—E), egg capsule (F) and paraspermatozoa (G—N) of Nodilittorina porcata group: N. atrata (A, E G, H), N. porcata (B, I), N. santelenae Reid, sp. nov. (C, J, K), N. parcipicta (D, L, M), N. albicarinata (E, N). A, E Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001159; shell H = 5.2 mm). B, I. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (BMNH 20001169; shell H = 5.0 mm). C, K. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000311; shell H = 5.0 mm). D. Bahia Santa Maria, Baja California Sur, Mexico (BMNH 20001173; shell H = 4.9 mm). E. Balandra, Baja California Sur, Mexico (BNMH 20001182; shell H = 4.8 mm). G. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000311). H. Muisne, Esmer- aldas, Ecuador (BMNH 20001161). J. Anconcito, Guayas, Ecuador (BMNH 20001170). L, M. Playa Coromuel, Baja California Sur, Mexico (BNMH 20001175). N. Playa Coromuel, Baja California Sur, Mexico (BNMH 20001185). Abbreviations and shading conventions for pallial oviducts: ag, albumen gland (light stipple; opaque and translucent portions not usually distinguishable in gross dissection); b, copulatory bursa (dashed line; visible by dissection; only the part separated as a sac from lumen of straight section of pallial oviduct is indicated); cb, constriction in copulatory bursa; eg, egg groove (thick line; visible externally when darkly pigmented and if not concealed by swollen oviducal glands); ocg, opaque capsule gland (mid stipple); sr, seminal receptacle (heavy stipple); tcg, translucent capsule gland (cross-hatching); some internal folding of lumen in straight section is visible by transparency. Scale bars A-E = 1 mm; F = 0.1 mm; G—N = 20 pm. Page 104 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 observation, Anconcito, Peninsula Santa Elena). As in all members of the N. porcata group, sculpture and color vary widely; the palest, smoothest, most elongate shells were found among algae in the sheltered microhabitat of a shallow pool, whereas samples from among barnacles on exposed headlands were dark, ribbed, and lower spired. This distinction was maintained over a distance of a few meters on a shore at Anconcito, suggesting that ecophenotypic influences may be important (see Discus- sion). Confusion is possible with two species with which it is syntopic, N. atrata and N. paytensis. The former has a more rounded, globular, slightly patulous shape, with a distinctive black and white pattern (including a promi- nently striped base) or entirely white shell; the penis of N. atrata has a narrower tip and larger mamilliform pe- nial gland, carried on a longer projection of the base. Juvenile N. paytensis of similar size are tall-spired, with flat whorls giving a conical outline, and an angled pe- riphery; the surface is glossy, with regular incised pri- mary grooves and no raised ribs; the color pattern of dark brown with pale sutural and basal bands is similar, but brown axial flames are usually prominent, especially at the suture. Nodilittorina santelenae was also syntopic with N. fuscolineata at Punta Carnero, the type locality of both; the latter species is more low spired and globular, with a lined or dashed pattern on prominent ribs, and penial form is diagnostic of both. The smooth-shelled form of N. santelenae shows a remarkable convergence with the shell of the broadly sympatric (but not syntopic) Littoraria rosewateri Reid; although the latter is larger (5-12 mm), coloration and sculpture are similar (cf. Reid, 1999a: fig. 9A), but anatomically it is quite different (the penis lacks a mamilliform gland but shows a glandular disc, the penial vas deferens is closed and the oviduct is multispiral) and the usual habitat is among supralittoral marsh grass in mangrove areas, so confusion is unlikely. Nodilittorina fuscolineata Reid, sp. nov. (Figures 2A—E, 3II, 5D, 6) Etymology: Latin: “‘dark-lined,” in reference to color pattern. Types: Holotype BMNH 19990422 (Figure 2A). Type Page 105 locality: Punta Carnero, Peninsula Santa Elena, Guayas Province, Ecuador. Taxonomic history: This species has not previously been recognized as distinct. It is rare in museum collections, and generally found in mixed lots with N. atrata. Some of the authors writing on N. atrata (and its synonyms) in Central America (see Synonymy of N. atrata) might have included this species, but owing to its rarity this is un- likely. Diagnosis: Shell small, globular to turbinate, often trans- lucent; usually with strong spiral ribs and microstriae; large, perforated pseudo-umbilicus; pale, with brown lines or long dashes on ribs. Penis with long, pointed filament, small mamilliform gland closely attached to base, no glandular disc. Material examined: 15 lots (including | penis, | radula). Shell (Figures 2A—E): Shell height to 2.8 mm. Shape turbinate to globular or slightly patulous (H/B = 1.00-— 1.25, SH = 1.38-1.67); whorls well rounded, suture dis- tinct; usually delicate and translucent. Columella straight, narrow, expanded and flattened at base; pseudo-umbilicus moderate to large, perforated, outlined by sharp keel con- tinuous with outer apertural lip. Sculpture of rather uni- form spiral ribs; on spire whorls 1—3 ribs visible; on last whorl 2-3 ribs on base, peripheral rib, and 3—4 ribs above periphery, rarely with 1 or 2 smaller interpolated riblets on last whorl; ribs vary from low and rounded to sharp and raised, but are rarely absent; spiral microstriae pre- sent over entire surface. Protoconch 3.0 whorls, 0.34 mm diameter, with fine spiral riblets. Color cream to pale brown, usually with continuous brown lines or long dash- es on ribs, and a band or a few large blotches at suture; occasionally pattern is irregularly marbled, but sutural blotches and lines on base remain visible; aperture with external pattern showing through, columella purplish or pale brown. Animal (description of holotype): Head black, narrow unpigmented stripe across snout, two black lines along tentacle, not meeting at tip; sides of foot black. Penis (Figure 3II): filament long, pointed, not twisted; sperm groove extending to filament tip; single small mamilli- form penial gland closely attached to base at 0.25 total Figure 5. Radulae of Nodilittorina porcata group: N. atrata (A), N. porcata (B), N. santelenae Reid, sp. nov. (C), N. fuscolineata Reid, sp. nov. (D), N. parcipicta (E, F), and N. albicarinata (G, H). A. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (BMNH 20001163; at 45°; shell H = 5.0 mm). B. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (BMNH 20001169; at 45°; shell H = 5.0 mm). C. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000311; at 45°; shell H = 5.0 mm). D. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 19990422, holotype of N. fuscolineata Reid, sp. nov.; at 45°; shell H = 2.8 mm). E, E Topolobampo, Sinaloa, Mexico (BMNH 20001176; two views of radula, flat and at 45°; shell H = 4.7 mm). G, H. San Felipe, Baja California Norte, Mexico (BMNH 20001183; two views of radula, flat and at 45°; shell H = 5.2 mm). Scale bars = 20 pm. Page 106 The Veliger, Vol. 45, No. 2 120° 110° 100° 90° 80° 2 es | oe 30° 20° 10° @ N. atrata © N. porcata * N. santelenae ¥ N. fuscolineata A N. parcipicta 4 N. albicarinata 10° 120° 110° 100° 90° 80° 70° Figure 6. Geographical distribution of Nodilittorina porcata group (all records based on material examined). D. G. Reid, 2002 penial length; glandular disc absent; base slightly pig- mented. Sperm not seen. Pallial oviduct not seen. Spawn not observed; protoconch indicates planktotrophic devel- opment. Radula (Figure 5D): Relative radular length unknown. Rachidian: length/width 1.06; major cusp pointed and leaf-shaped. Lateral and inner marginal: major cusps moderately pointed. Outer marginal: 6 cusps. Habitat: Of the available collections, only the holotype was collected alive, among barnacles in the upper eulit- toral, on an exposed siltstone headland on a sandy coast. The typical habitat of this species is uncertain. All other material seen (14 lots in LACM) was collected dead in sediments from depths of 2-100 m, often mixed with N. atrata; neither N. atrata nor any other member of the genus occurs subtidally, so this must represent material washed from the eulittoral zone. Many live collected sam- ples of the broadly sympatric N. atrata are available from within the range of this species, yet only at the type lo- cality has a single N. fuscolineata been found among them. A possible explanation is that this species is found in relatively exposed or offshore localities (where sam- pling is less frequent), unlike N. atrata which occupies a range of habitats. This is supported by the fact that many of the localities for dead N. fuscolineata (as well as the type locality) are peninsulas or islands; furthermore, it appears to be absent from relatively sheltered mainland sites such as the Panama Canal Zone and the Golfo de Nicoya in Costa Rica (both represented by numerous and large collections of N. atrata). Range (Figure 6): El Salvador to southern Ecuador. Range limits: Isla Zacatillo, Golfo de Fonseca, El Sal- vador (LACM 73-57, 1 specimen); Bahia Jobo, Costa Rica (LACM 72-17); Isla del Cano, Costa Rica (LACM 72-63); Bahia Honda, Panama (LACM 38-131, 1 speci- men); Isla Taboga, Panama (LACM 65-25, 1 specimen); Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 19990422, holotype only). Remarks: As mentioned above, this species is so far rep- resented by only a single live-collected specimen, as well as 50 dead shells from 14 localities (LACM), and is there- fore by far the rarest of the N. porcata group in museums. This may reflect a less accessible habitat (see Habitat). The shell of N. fuscolineata is distinctive, with regular ribs marked by brown lines or dashes, well rounded whorls and delicate texture, and these characters make it easily separable from the broadly sympatric N. atrata (a larger, more solid shell, very variable in form, but never with such rounded spire whorls nor with a lined pattern). The shell characters are, however, somewhat similar to those of N. parcipicta, although that species is larger (to ‘5.9 mm), more solid, and has a finer spotted (rarely dashed, and never lined) pattern on the ribs, or may even be unpatterned. Fortunately, the sole living specimen ex- Page 107 amined was a male and, assuming this to be typical, the penial shape is diagnostically different from those of both N. atrata and N. parcipicta. The penis is more similar to that of the latter in its lack of a marked twist to the fil- ament tip. Their geographical ranges are not known to overlap, N. parcipicta being restricted to Mexico. These shell and penial similarities suggest that N. fuscolineata and N. parcipicta are sister species. If the inferred habitat of N. fuscolineata on exposed shores is correct, this is another similarity between the two. Nodilittorina parcipicta (Carpenter, 1864) (Figures 2F—-M, 3W-CC, 4D, L, M, 5E, EF 6, 22F) Fossarus parcipictus Carpenter, 1864a:476 (Cape St Lucas {Cabo San Lucas, Baja California, Mexico]; lectotype (Palmer, 1963) USNM 4060, seen, Palmer, 1963:pl. 65, figs. 4, 5, Figure 2L herein; paralectotype USNM 678706, seen). Palmer, 1963:342, pl. 65, figs. 4, 5. Keen, 1971:454. Abbott, 1974:136 (may include N. atrata or N. fuscolineata). Skoglund, 1992:34. Fossarus cf. atratus—McLean, 1970:127 (not Littorina atrata C. B. Adams, 1852 = N. atrata). Taxonomic history: This species has been largely ne- glected since its description, and has not hitherto been referred to a littorinid genus. The lectotype was figured by Palmer (1963), and the name was listed by Keen (1971) and Abbott (1974). The latter gave a range ““Baja California to Panama,” but the species does not occur so far south, and records of N. atrata and/or N. fuscolineata may have been included. In describing the new species N. albicarinata, McLean (1970) remarked that it often occurred together with ‘‘a species of Fossarus, cf. atra- tus” by which, from the brief description, he apparently intended N. parcipicta; this is supported by the inclusion of one specimen of N. parcipicta among the paratypes of N. albicarinata (LACM 1400). Diagnosis: Shell small, globular to turbinate; strong spiral ribs and microstriae; large, perforated pseudo-umbilicus; white or yellow, with small brown spots on ribs. Penis with broad, blunt filament, large mamilliform gland close- ly attached to base, no glandular disc. Material examined: 30 lots (including 15 penes, 4 sperm samples, 5 pallial oviducts, 4 radulae). Shell (Figures 2F—M, 22F): Mature shell height 2.3— 5.9 mm. Shape turbinate to globular or slightly patulous (H/B = 0.83-1.25, SH = 1.27—1.74); whorls rounded, suture distinct. Columella straight, narrow, expanded, and flattened at base; pseudo-umbilicus usually large, perfo- rated, outlined by sharp keel continuous with outer ap- ertural lip, but sometimes narrow or imperforate. Sculp- ture of rather uniform, sharp spiral ribs; on spire whorls only 1—2 ribs visible; on last whorl 2—3 ribs on base, peripheral rib, and 2—4 ribs above periphery, but with smaller interpolated ribs on largest shells total number on Page 108 The Veliger, Vol. 45, No. 2 last whorl up to 11; ribs vary from low to strongly cari- nate; spiral microstriae present over entire surface (Figure 22F). Protoconch 2.7 whorls, 0.34 mm diameter. Color white to pale yellow, sometimes lacking pattern, but usu- ally with small brown spots on ribs; darkest shells have irregular axial stripes, blotches or transverse dashes of dark brown or black; aperture with external pattern show- ing through, only rarely with peripheral dark band or pale anterior stripe, columella cream to dark brown. Animal: Head black to grey, unpigmented stripe across snout, two black lines along tentacle, not meeting at tip; sides of foot speckled black to pale grey. Opercular ratio 0.39—-0.42. Penis (Figures 3W—CC): filament broad, blunt, or minutely pointed, not (or only slightly) twisted; sperm groove extending to filament tip; single large mamilliform penial gland closely attached to base at 0.2—0.4 total pe- nial length (mamilliform gland absent in one specimen); glandular disc absent; base often slightly pigmented. Eus- permatozoa 64—93 zm; paraspermatozoa (Figures 4L, M) oval; rod-pieces single (rarely 2—3), usually projecting at both ends or at least filling cell, 16-28 ym, slightly ta- pering or fusiform, ends rounded; granules large, spher- ical, distinct. Pallial oviduct (Figure 4D) with flexure and constriction between spiral and straight sections; copula- tory bursa opening near anterior end of straight section, constricted at about one-third of its length, extending back beneath capsule gland. Spawn not observed; proto- conch indicates planktotrophic development. Radula (Figures 5K, F): Relative radular length 1.2—2.1. Rachidian: length/width 1.06—1.44; major cusp pointed and elongate leaf-shaped. Lateral and inner marginal: ma- jor cusps pointed or slightly rounded. Outer marginal: 5— 6 cusps. Habitat: In small, shallow rock pools in upper eulittoral; in crevices among barnacles; on granite, conglomerate and concrete; wave-exposed headlands, and sometimes sheltered bays. Range (Figure 6): Southern Baja California, mainland coast of Mexico from Sinaloa to Michoacan. Range lim- its: Bahia Magdalena, Baja California Sur (USNM 218336, | specimen); Punta Lobos, Todos Santos, Baja California Sur (BMNH 20001172); Bahia Santa Maria, near Cabo San Lucas, Baja California Sur (BMNH 20001173); Playa Coromuel, 3 km N of La Paz, Baja California Sur (BMNH 20001175); El Requeson and El Coyote, Bahia Concepcion, Baja California Sur (LACM 63-37): Topolobampo, Sinaloa (BMNH 20001176); Ma- zatlan, Sinaloa (BMNH 20001177); Punta Telmo, Mi- choacan (BMNH 20001181). This species only just pen- etrates the Gulf of California, but is common at its limits at both Bahfa Concepcion and Topolobampo. The lack of records south to Oaxaca may simply reflect lack of col- lecting of this small species with a preference for exposed and inaccessible localities. Remarks: This species is somewhat less variable in shell characters than others in the NV. porcata group; most spec- imens show a spotted pattern, and it is not known to occur in a smooth form. Although sometimes found on shel- tered shores, most of the available samples are from wave-exposed shores, which are more strongly exposed than shores on which other members of this group have been found. This, combined with its restriction to the shores of Baja California and southern Mexico, and ab- sence from most of the Gulf of California, emphasizes the oceanic character of its distribution. A similar distri- bution on the coast of Mexico is shown by the likewise oceanic species Littoraria pintado pullata (Carpenter), al- though that species also occurs on the eastern Pacific is- lands (Reid, 1999a). There is limited sympatry between N. parcipicta and N. albicarinata, but the latter is found only in moderately sheltered habitats, and there are only three recorded in- stances of syntopy. At Playa Coromuel (personal obser- vation) both species were common among the uppermost barnacles on a sheltered shore, but N. parcipicta was found mainly at slightly lower tidal levels than N. albi- carinata, and the spire whorls of the former were more strongly eroded. At Topolobampo (personal observation) only a single N. albicarinata was found together with moderately common WN. parcipicta, among sparse barna- cles on a concrete ramp, in a sheltered, silty bay. In ad- dition, both species are recorded from El Requeson, Ba- hia Concepcioén (LACM 1400), and said to occur together by McLean (1970). These two species are easily distin- guished by shell characters; N. albicarinata is usually im- perforate, often somewhat tall-spired, smooth, and grey to white in color, unlike any shell of N. parcipicta; sculp- tured forms of N. albicarinata are sharply carinate at the shoulder and periphery, and (at least on the spire whorls) the carinae are white on a brown ground, unlike the more globular, umbilicate shells of N. parcipicta with regular spotting on uniform, rounded ribs. A more similar shell is that of NV. fuscolineata, but that is distinguished by smaller size, delicate texture, and pat- tern of brown lines or long dashes on the ribs; the two are allopatric (N. fuscolineata occurring to the south of El Salvador) and are possible sister species (see Remarks on N. fuscolineata). Nodilittorina albicarinata (McLean, 1970) (Figures 2N—W, 3V, DD—-HH, 4E, N, 5G, H, 6) Littorina dubiosa—McLean, 1961:464 (not C. B. Adams, 1852 = N. dubiosa). Littorina albicarinata McLean, 1970:127, fig. 36 (El Reque- son, Concepcion Bay, Baja California, 26°38'N, 111°50'W; holotype LACM 1399, seen, Figure 20; 263 paratypes LACM 1400, seen, one is N. parcipicta; 4 paratypes USNM 681630, seen; 4 paratypes each AMNH, ANSP, CAS, MCZ, SBM). Keen, 1971:365, fig. 180. D. G. Reid, 2002 Page 109 Littorina (Littorinopsis) albicarinata—Abbott, 1974:69, fig. 566. Littorina (Fossarilittorina) albicarinata—Rosewater, 1981: 30. Nodilittorina (Nodilittorina) albicarinata—Reid, 1989a:99. Skoglund, 1992:15. Taxonomic history: McLean (1961) at first identified the smooth form of this species as Littorina dubiosa, and sug- gested that keeled shells might belong to the same spe- cies. Later (1970), he described the distinctive form with white carinae under the new name, and again remarked on the variation in sculpture. The species is abundant within its range, and the paucity of literature references is a reflection of the relatively few malacological studies in the Gulf of California. In ANSP and USNM there are several lots of the tall-spired, smooth, white form of this species labelled “Littorina cognatus Hemphill, MS”’; this name does not appear to have been published and was not included in the list of Hemphill’s taxa by Coan & Roth (1987). Diagnosis: Shell small, turbinate to tall; smooth with im- pressed striae, or carinate with microstriae; narrow, im- perforate pseudo-umbilical area; often grey to white; if patterned, then white carinae on brown shell, especially on spire. Penis with pointed, slightly twisted filament tip, opening of sperm groove behind tip, large mamilliform gland on stout or long lateral appendage, no glandular disc. Material examined: 40 lots (including 19 penes, 4 sperm samples, 6 pallial oviducts, 7 radulae). Shell (Figures 2N—W): Mature shell height 2.3—7.6 mm. Shape turbinate to tall-spired (H/B = 1.13-1.77; SH = 1.46—2.30); spire whorls rounded, suture distinct; periph- ery of last whorl only slightly angular, but may be marked by a rib or carina; solid. Columella straight, narrow, slightly pinched at base of pillar; pseudo-umbilicus usu- ally only a narrow, imperforate area or absent, but some- times narrowly perforated. Sculpture variable; smoothest shells with 6—13 impressed lines above periphery (some- times increasing to 23 on last whorl) and similar but less distinct fine striae on base, periphery usually marked by a slight rib; almost all shells have a prominent rib at shoulder and another at periphery of early spire whorls (may be lost by erosion), even if they become smooth on last whorl; strongly sculptured shells with shoulder and peripheral ribs persisting as sharp carinae, with additional 2 ribs below suture, 1 between carinae, and 3 on base, giving total of 8 more or less carinate ribs, with coarse microstriae between; periostracum occasionally produced into minute bristles (less than 100 pm) on basal and pe- ripheral ribs of strongly sculptured shells. Protoconch 2.8 whorls, 0.29-0.34 mm diameter. Color variable; spire usually brownish with white dashes or lines marking shoulder and peripheral rib; pattern may persist, with white carinae and ribs on brown ground; shells often white, fawn, or chalky blue-grey on last whorl; occasion- ally with fine brown spots, mottling or fine axial zigzags on last whorl, strongest at suture and periphery; color pattern always fades to white toward inner part of base; columella and aperture brown, with anterior unpigmented band, columella sometimes white. Animal: Head and sides of foot black; two black lines along tentacle, meeting (or almost so) at small black ter- minal spot. Opercular ratio 0.44—0.51. Penis (Figures 3V, DD-HH): filament tip pointed and slightly pinched; sperm groove with a kink, not extending to filament tip; single large mamilliform penial gland on stout (and in fully relaxed specimens very long) lateral appendage at 0.4—0.5 total penial length; glandular disc absent (but in contracted specimens an extension of glandular material of mamilliform gland may resemble a small glandular disc); base pigmented. Euspermatozoa 71-86 wm; para- spermatozoa (Figure 4N) oval; rod-pieces single, filling cell or projecting at one or both ends, 16—24 wm, blunt or slightly rounded at ends, parallel-sided or occasionally slightly tapering; granules large, spherical, distinct. Pallial oviduct (Figure 4E) with flexure and constriction between spiral and straight sections; copulatory bursa opening at anterior end of straight section, extending back to start of spiral portion. Spawn not observed; protoconch indicates planktotrophic development. Radula (Figures 5G, H): Relative radular length 1.9— 3.1. Rachidian: length/width 1.13—1.54; major cusp point- ed and elongate leaf-shaped. Lateral and inner marginal: major cusps pointed or slightly rounded. Outer marginal: 6-8 cusps. Habitat: Among uppermost barnacles and in crevices, upper eulittoral; on volcanic conglomerate, basalt, con- crete; sheltered coasts; often abundant; habitat notes with one lot (Puerto Lobos, Sonora, Mexico, USNM 862206) “in grasses, presumably supralittoral halophytic salt- marsh grass. Range (Figure 6): Southwestern Baja California and Gulf of California. Range limits: Laguna Manuel, Baja California Norte (USNM 106528); Punta Abreojos, Baja California Sur (USNM 265774); Bahia Magdalena, Baja California Sur (USNM 332443); Ensenada de los Muer- tos, Baja California Sur (G. J. Vermeij Collection); Bal- andra, 30 km N of La Paz, Baja California Sur (BMNH 2001182); San Felipe, Baja California Norte (BMNH 20001183); Puerto Penasco, Sonora (USNM 665246); Punta San Antonio, Guaymas, Sonora (LACM 73-6); To- polobampo, Sinaloa (BMNH 2001184, 1 specimen). The distribution of this species is apparently disjunct, with no records from the inhospitable exposed coast between La Paz and Bahia Magdalena. It is apparently common far- ther north in suitable lagoonal and sheltered habitats on the western coast of Baja California. Although common Page 110 The Veliger, Vol. 45, No. 2 Table 2 Summary of the most useful characters for the identification of the two species of the Nodilittorina modesta group. Character 1. Geographical range Clipperton Atoll i) Shell —primary grooves on spire whorls —all white form usually 6-7 shells —color pattern last whorl 3. Tentacle pattern 4. Penis —filament length long, 0.7—0.8 total length —filament tip tapering to pointed tip N. modesta Baja California, Mexico, Costa Rica, yes, especially in strongly sculptured if present, minute grey-brown dots on white shell, often becoming obsolete on fine transverse black lines N. conspersa Oaxaca (Mexico), El Salvador to Ecuador, Isla del Coco, Galapagos Islands usually 4—5 no, always patterned always with small orange-brown dots on white shell two longitudinal black lines short, 0.25—0.35 total length bluntly hooked tip at Guaymas, only a single specimen was found in a suit- able habitat at Topolobampo (personal observation). Remarks: Confusion is possible with two or three sym- patric species. It is only rarely syntopic with N. parcipicta among barnacles, in the narrow zone of sympatry in southern Baja California and the southeastern Gulf of California, but the shells of these two species are readily discriminated (see Remarks on N. parcipicta). In the Gulf of California N. albicarinata occurs on the same shores as N. penicillata, a larger species lacking carinate sculp- ture, of which juveniles show a diagnostic shell pattern of axial brown lines with a spiral brown line on the shoul- der and another on the base. Another broadly sympatric species is Littoraria rosewateri Reid; although there are no available records of these two occurring syntopically, they may well do so, since the typical habitat of L. rose- wateri is among supralittoral marsh grasses, from which a sample of N. albicarinata has been collected (see Hab- itat). The shells of these two species can be remarkably similar. Littoraria rosewateri closely resembles tall- spired, smooth forms of N. albicarinata, but the former reaches larger size (S—12 mm), never shows an enlarged peripheral or shoulder rib on early whorls or on last whorl, the color is polymorphic in large samples, and there is never a pale anterior band within the aperture. Anatomical characters are diagnostic; the tentacles of L. rosewateri show transverse bands, the penis has a large glandular disc and no mamilliform penial gland, and the pallial oviduct is multispiral. It is interesting that the al- gal-dwelling form of N. santelenae also shows conver- gence with L. rosewateri. Recently it has been suggested that the radulae of Lit- toraria species show ecophenotypic plasticity of cusp shape according to the substrate, whether rock or plants (Reid & Mak, 1999). It is unusual to find a member of the genus Nodilittorina on a plant substrate, providing an opportunity to test this hypothesis in the genus. Two rad- ulae were examined from the sample collected on grasses, but did not display any differences from the rest. The Nodilittorina modesta Group In the older literature, the familiar white littorinids of the eastern Pacific, usually with a pattern of minute brown dots, were generally known by the specific name of conspersa Philippi, 1847, but then for the past 30 years by the earlier name of modesta Philippi, 1846 (Rosewater, 1970; Keen, 1971; Reid, 1989a). However, close exami- nation of penial shape has revealed two species in this group, with sympatry at two localities in southern Mexico and Costa Rica. The penial differences are small, but en- tirely consistent even in sympatry, and are correlated with shell differences (Table 2). Philippi (1846a, 1847) named four species in this group, and from his precise descrip- tions of shell sculpture it is possible to identify the two valid species as N. modesta and N. conspersa, although their synonymies are complex. These two species are evidently sister taxa. They share a similar white shell, often with a pattern of brown dots. This pattern is difficult to quantify, since although the dots are laid down along the prosocline growing edge of the shell, their alignment is chiefly in opisthocline series or somewhat irregular, and bears no constant relation to the conspicuous spiral sculpture of the shell. (For com- parative purposes, in the descriptions below the dots have been counted along an opisthocline series between pe- riphery and suture on the last whorl). In both species the shell varies from rather smooth to strongly sculptured with spiral grooves, sometimes within a sample, but no correlation with microhabitat or geographical range has been noticed. They share several unusual (probably syn- apomorphic) anatomical features of the penis, oviduct, and radula. The penis is elongate, lacks a mamilliform D. G. Reid, 2002 gland, and the glandular base is not clearly differentiated into a glandular disc, in contrast to all other known No- dilittorina species except the two Atlantic species N. me- leagris and N. mespillum (Mihlfeld). In the pallial ovi- duct, a loop of the renal oviduct projects into the center of the spiral loop of the albumen gland, which has not been seen in other Nodilittorina species. The radulae share the presence of an additional pair of denticles at the concave anterior edge of the rachidian tooth, which is absent elsewhere in the genus (or only slightly and variably developed in some individuals of the N. aspera group). Their habitat is also similar, in the upper eulittoral on wave-exposed shores, whereas other large species of the genus occupy the littoral fringe. Specimens of both species from localities in Oaxaca and Costa Rica sometimes contained a commensal poly- clad platyhelminth (R. Sluys, personal communication). Single worms up to 5.5 mm long are found in the mantle cavity, which they may fill completely, although the host sustains no apparent damage. A similar commensal has been observed in N. apicina and N. tenuistriata, but has not apparently been recorded in other littorinids. Nodilittorina modesta (Philippi, 1846) (Figures 7A-F 8A-E N, P, Q, 9A, B, 10, 22G, H) Littorina modesta Philippi, 1846a:141 (Sitka, Nova Albion [Alaska]; insulam Mauritii [Mauritius]; both in error, here restricted to Mazatlan, Mexico; lectotype (here designated, 19.6 X 13.2 mm, ‘Sitka’) BMNH 1968224, seen, Philippi, 1847:Litorina pl. 6, fig. 12, Figure 7E herein; 3 paralectotypes BMNH 1968224, seen; 3 ad- ditional specimens probably from same lot, BMNH 19990404, seen). Middendorff, 1849:394. Carpenter, 1857a:216, 224, 286. Reeve, 1858:sp. 107, pl. 18, fig. 107. Keen, 1958:282. Keen, 1971:366, fig. 183 (in part, includes N. conspersa). Holguin & Gonzalez, 1989:115, fig. Litorina modesta—Philippi, 1847:3:48—49, Litorina pl. 6, fig. 12. Menke, 1851:164. Carpenter, 1857a:237, 326. Weinkauff, 1882:52—53, pl. 6, figs. 13, 16. Litorina sitchana var. modesta—Carpenter, 1864b:655. Littorina (Littorinopsis) modesta—Rosewater, 1970:423. Abbott, 1974:69 (in part, includes N. conspersa). Nodilittorina (? Fossarilittorina) modesta—Reid, 1989a:98 (in part, includes N. conspersa). Nodilittorina modesta—Emerson, 1995:13 (in part, includes N. conspersa). ? Litorina albida Philippi, 1848:3:63—64, Litorina pl. 7, fig. 9 (Real Llejos [El Realejo, Nicaragua]; types not found). ? Weinkauff, 1882:81, pl. 11, fig. 1. ? Littorina (Littorinopsis) albida—von Martens, 1900:576, 582. Litorina conspersa—Carpenter, 1857a:257 (in part, includes N. conspersa). Carpenter, 1864b:541, 598, 623 (in part, includes N. conspersa). Weinkauff, 1883:217 (in part, includes N. conspersa). Litorina (Melaraphe) conspersa—Carpenter, 1857b:346— 347 (in part, includes N. conspersa). Page 111 Littorina (Melaraphe) aspera var. conspersa—Tryon, 1887: 249, pl. 44, figs. 80, 81 (in part, includes N. conspersa). Littorina (Melarhaphe) conspersa—von Marttens, 1900:577, 586 (in part, includes N. conspersa). Littorina conspersa—Pilsbry & Lowe, 1932:124 (not Phi- lippi, 1846). Keen, 1958:282, fig. 174 (in part, includes N. conspersa). Villamar, 1965:123 (not Philippi, 1846). Littorina (Melarhaphe) philippii var. alba von Martens, 1900:577, 585, pl. 43, fig. 13 (Mazatlan, Mexico; 5 syn- types MNB 102847, seen). Littorina (Melarhaphe) conspersa var. puncticulata—von Martens, 1900:577, 786-587 (in part, includes N. con- spersa; not Philippi, 1847 = N. conspersa). Littorina aspera—Keen, 1971:365, fig. 181 (part) (in part, includes N. aspera, N. penicillata, N. dubiosa, N. api- cina, N. interrupta). Taxonomic history: Philippi was meticulous in his de- scriptions of details of shell shape and sculpture, but he had limited material available, leading him to describe four species in the N. modesta group. The identity of the oldest of these, Littorina modesta Philippi, 1846, is clear; it was described from material in the Cuming Collection (BMNH), and the specimen figured by Philippi (1847) is here designated lectotype. Philippi (1847) himself de- scribed the characteristically numerous and deep grooves of the shell. The listing of Litorina albida in the syno- nymy of N. modesta is not certain; the types are lost, and its inclusion is based on the rounded whorls, 5—6 primary spiral grooves, white columella with brown margin, and dark brown posterior aperture, all described by Philippi (1848); this species has not since been recorded from Nic- aragua, but it is within the known range. The second spe- cies in the N. modesta group is here identified as N. con- spersa (Philippi, 1847), with Litorina puncticulata Philip- pi, 1847, as a synonym. The only other available name was introduced by von Martens (1900) for young speci- mens of N. modesta; these he described as var. alba of Littorina philippii (tself a synonym of N. apicina), ap- parently misled by the axial lines of brown dots. Although few subsequent authors have described shells in such detail as Philippi, the largely separate geograph- ical distributions of the two species make it possible to compile the synonymies of each. However, it was an error in the type locality of Littorina modesta that led to an initial confusion in the nomenclature of this group. Phi- lippi (1846a, 1847) described Littorina modesta from Sit- ka (Alaska) and Mauritius. Subsequent authors therefore generally used either the names conspersa and puncti- culata (Adams, 1852a, b) or conspersa alone (e.g., Car- penter, 1857a, b, 1863, 1864b; Weinkauff, 1883; von Martens, 1900; Keen, 1958) for the two species now rec- ognized in the tropical eastern Pacific. The earlier name modesta was correctly used only by Menke (1851); others employed it for a species believed to occur in the northern Pacific (Middendorff, 1849; Carpenter, 1857a, b; Reeve, 1858; Weinkauff, 1882; Keen, 1958). Carpenter (1863, 1864b) even suggested that this enigmatic modesta was Page 112 a variety of the northern Pacific Littornia sitkana Philippi, 1846. This confusion was eventually resolved by exami- nation of the types of Littorina modesta, and the name was reinstated for the supposed single species of the trop- ical eastern Pacific (Rosewater, 1970; Keen, 1971); it has been used in this sense by all subsequent workers. Some authors have had an even broader concept of these species, combining them in various ways with members of the N. aspera group. Tryon (1887) reduced the N. modesta group to a subspecies of Littorina aspera (followed only by Schwengel, 1938). Von Martens (1900) described heavily marked specimens of N. modesta as a variety of Littorina philippii (= N. apicina), and his fig- ure was reproduced as “‘Littorina aspera” by Keen (1971). It has also been suggested that N. paytensis is a southern subspecies of Littorina modesta (Keen, 1971; Vermeij, 1973; Rosewater, in Finet, 1985). Only Philippi (1847), Weinkauff (1882; who followed Philippi’s species concepts almost exactly), and C. B. Ad- ams (1852a, b) have previously recognized more than one species in the N. modesta group in Central America, bas- ing distinctions on differences in shell outline and degree of sculpture. These features are in fact more variable within the two species of the group than was recognized by these early authors, so that their distinctions do not correspond exactly to that made here on anatomical grounds (see also Taxonomic History of N. conspersa). Diagnosis: Shell moderately large, spire whorls moder- ately rounded; 6—7 primary spiral grooves: sculpture of incised lines only, or with deep grooves 1—3 times rib width; all white or with minute grey-brown dots. Tenta- cles with fine transverse black lines. Penis with long, ta- pering filament, glandular flange at base, no mamilliform gland. Material examined: 58 lots (including 26 penes, 4 sperm samples, 7 pallial oviducts, 5 radulae). Shell (Figures 7A—F, 22G, H): Mature shell height 4.5— 19.6 mm. Shape high turbinate (H/B = 1.33—1.79, SH = 1.38-1.89); spire whorls moderately rounded, suture dis- tinct; periphery of last whorl weakly angled. Columella straight, broad, hollowed, and pinched (sometimes with slight protruberance) at base; occasionally a small imper- forate pseudo-umbilical area; eroded parietal area in larg- er shells. Sculpture of 6—7 (rarely 5 or 8) primary spiral grooves on spire whorls; these may remain as incised lines only (1—2 secondary grooves may appear near su- ture on last whorl), numbering 9-13 above periphery of last whorl (11-17 in total including basal grooves), or become wider and deeper near periphery, but sometimes become obsolete on last whorl; in strongly sculptured shells grooves are wider and deeper throughout, separat- ing rounded ribs on spire whorls, on last whorl, ribs are then raised (occasionally sharp), separated by grooves | to 3 times rib width, with narrow interpolated rib ap- The Veliger, Vol. 45, No. 2 pearing in grooves near suture (rarely in all grooves above periphery), grooves on last whorl then up to 20 above peripheral rib (up to 27 in total); spiral microstriae absent (Figure 22H). Protoconch 2.7 whorls, 0.31 mm diameter, sculptured by spiral ribs (Figure 22G). Color white, with pale brown or lilac-grey apex; often unpat- terned (especially when strongly sculptured); otherwise covered with small grey, brown, or black spots aligned in oblique (opisthocline) series (numbering 14—25 spots from peripheral rib to suture on last whorl); spots fre- quently become obsolete on last whorl; aperture pale or- ange-brown to dark brown, often darkest posteriorly, with broad pale basal band, usually also a more diffuse shoul- der band, external spotting showing through near margin (spotting may be visible even in externally unpatterned shells); columella white to brown, or white pillar with brown margin. Animal: Head (Figures 8A, E): Black to grey, unpig- mented stripe across snout, tentacle with fine transverse lines of black or grey, pale beneath; sides of foot black to pale grey. Opercular ratio 0.30—0.38. Penis (Figures 8A-F): filament long (about 0.7—0.8 total length), taper- ing to pointed or slightly mucronate tip, subepithelial glandular tissue near tip and surrounding sperm groove along anterior edge, filament differentiated from base by smooth anterior edge and slight constriction below swol- len glandular sides of sperm groove (differentiation some- times indistinct); sperm groove open to tip; base with annular wrinkles except at posterior edge with slight glan- dular flange (opaque subepithelial glandular tissue some- times visible, approaching surface at minute papilla, al- though this is not a true mamilliform gland), base occa- sionally slightly pigmented. Euspermatozoa 57—61 wm; paraspermatozoa (Figures 8P, Q) round to oval; rod-piec- es single (rarely two), filling cell, 13-21 wm, broad, bluntly rounded, hexagonal in section; granules large, spherical, distinct. Pallial oviduct (Figure 8N) with long straight section; large copulatory bursa opening near pos- terior end of straight section, extending back to albumen gland; small loop of renal oviduct usually projects into center of spiral of albumen gland. Spawn not observed: protoconch indicates planktotrophic development. Radula (Figures 9A, B): Relative radular length 2.5—5.9. Rachidian: length/width 1.21—1.47; major cusp elongate, blunt or rounded at tip; 2 extra denticles at concave an- terior edge. Lateral and inner marginal: major cusps elon- gate rectangular, blunt at tip. Outer marginal: 8—10 cusps. Habitat: Rock faces, shallow rock pools, and among bar- nacles and mussels; in upper eulittoral; recorded on gran- ite and volcanic conglomerate; usually on wave-exposed open coasts, apparently rare at sheltered sites. A study of zonation and temperature relations by Markel (1971) in- cluded both this species and N. conspersa (as Littorina modesta). D. G. Reid, 2002 Range (Figure 10): Southern Baja California, southern Gulf of California, Mexico, Costa Rica, Islas Revillagi- gedo and Clipperton Atoll. Range limits: Bahia Magda- lena, Baja California Sur (USNM 264568, 2 specimens): 4 km S of Todos Santos, Baja California Sur (USNM 794301): Bahia Santa Maria, near Cabo San Lucas, Baja California Sur (BMNH 20001187): Punta Pescadero, Baja California Sur (BMNH 20001188): Playa Coromuel, 3 km N of La Paz, Baja California Sur (BMNH 20001189, 1 specimen): Isla Espiritu Santo, Baja California Sur (USNM 538110, 1 specimen): Isla Carmen, Baja Cali- fornia Sur (USNM 558508. 1 specimen): Guaymas, So- nora (BMNH 20001190, 1 specimen: USNM 701409, 4 specimens): Topolobampo, Sinaloa (BMNH 20001191, 3 specimens): Mazatlan, Sinaloa (BMNH 20001192): Puerto Angel, Oaxaca (BMNH 20001192); Playa de Ma- nuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001194, 40 specimens); Isla Socorro (USNM 60648; KLK): Clipperton Atoll (KLK, 2 specimens). The species is rare in the Gulf of California (a total of only 12 spec- imens have been seen from north of La Paz and Maza- tlan). There is only a single locality record from Central America, although 40 specimens were collected. The spe- cies is common on Isla Socorro (and was also listed from Isla Clarion by Emerson, 1995), but only two specimens are known from Clipperton Atoll, where it is probably an occasional immigrant (it was not recorded in a list of the mollusks by Emerson, 1994). As discussed in the Taxo- nomic History above, N. modesta was for long thought to occur in the northern Pacific, following the erroneous locality of Sitka given by Philippi (1846a, 1847). Remarks: This species is closely similar to the other member of the modesta group, N. conspersa: the char- acters most useful for discrimination are listed in Table 2. Geographical range is a useful criterion. So far, sym- patric collections have been seen from only two localities, Puerto Angel (Oaxaca, Mexico) and near Puerto Quepos (Costa Rica), almost 1500 km apart: evidently both spe- cies sometimes disperse across the intervening Central American Gap (see Discussion). (If Litorina albida is cor- rectly synonymized with N. modesta, El Realejo in Nic- aragua is another site of sympatry.) In living or well pre- served animals, the shape of the penis is diagnostic, but the differences are subtle and sometimes hard to discern if the filament is not clearly differentiated from the base (e.g., Figures 8C. E). Surprisingly, the coloration of the tentacles provides an equally accurate diagnostic charac- ter, with fine black transverse lines in N. modesta and a pair of longitudinal black lines in N. conspersa. The para- spermatozoa differ slightly, the rod-pieces of N. modesta being broader. No significant differences were observed in the pallial oviducts or radulae. Without the benefit of anatomical information, shell variation in this group is initially confusing, since the most obvious features of the variation, strength of sculpture and presence of colored Page 113 dots, do not separate the two taxa. Instead, a subtle and not entirely diagnostic character, the number of primary spiral grooves on the spire whorls, is most useful. There are several other minor differences: all-white shells occur only in N. modesta: if present, the dots are smaller, more numerous and grey or blackish brown (rather than or- ange-brown) in N. modesta; sculpture may be weak or strong in both, but grooves do not exceed the width of the ribs in N. conspersa; the spire whorls are slightly flatter in N. conspersa. Individually, these differences seem insignificant but, nevertheless, at the localities of sympatry, all specimens can be separated by shell char- acters alone, and the majority of unlocalized shells can be confidently assigned. Nodilittorina conspersa (Philippi, 1847) (Figures 7G—K, 8G—M, O, R, S, 9C, 10) Litorina conspersa Philippi. 1847:2:200—201, Litorina pl. 4. fig. 14 (Oceanus Pacificus Real Llejos in America cen- trali [El] Realejo, Nicaragua]: neotype (here designated, 12.0 X 8.0 mm, El Realejo, Nicaragua) BMNH 199990405/1, seen, Figure 7J). Carpenter, 1857a:208. 230, 326 (in part, includes N. modesta). Carpenter, 1864b:538. 623 (in part, includes N. modesta). Wein- kauff, 1882:64—65, pl. 8. figs. 10, 11 (in part. includes N. modesta). Weinkauff, 1883:217 (in part, includes N. modesta). Stearns, 1891:327. Littorina conspersa—C. B. Adams, 1852a:396. C. B. Ad- ams, 1852b:172. Carpenter, 1857a:273. Merch, 1860: 69. Carpenter, 1863:352—353 (in part. includes N. mo- desta). Biolley. 1907:22. Morrison. 1946:10. Keen, 1958:282 (in part. includes N. modesta). Hertlein, 1963: 239} Littorina (Melaraphe) conspersa—H. & A. Adams. 1854: 314. von Martens, 1900:577, 586 (in part, includes N. modesta). Litorina (Melaraphe) conspersa—Carpenter, 1857b:346— 347 (in part, includes N. modesta). Littorina (Melaraphe) aspera var. conspersa—Tryon, 1887: 249, pl. 44. figs. 82, 83 (in part. includes N. modesta). Littorina aspera conspersa—Schwengel, 1938:2. Littorina puncticulata Philippi. 1847:2:201. Litorina pl. 4. fig. 15 (Oceanus Pacificus Real Llejos in America cen- trali [El Realejo, Nicaragua]: types not found). Wein- kauff. 1882:63, pl. 8, fig. 9 (in part. includes N. modes- ta). Littorina puncticulata—C. B. Adams, 1852a:396, 400. C. B. Adams, 1852b:176. Littorina (Melaraphe) puncticulata—H. & A. Adams, 1854: 314. Littorina (Melarhaphe) conspersa var. puncticulata—von Martens, 1900:577, 786-587 (in part. includes N. mo- desta). ? Littorina (? Littorinopsis) conspersa vat. fortisulcata Nev- ill, 1885:138 (Nicaragua: nomen nudum). Littorina modesta—Keen, 1971:366, fig. 183 (in part. in- cludes N. modesta). Montoya, 1983:332 (in part, in- cludes N. modesta). Finet, 1985:13 (not Philippi, 1846). Alamo & Valdivieso, 1987:26, fig. 39 (not Philippi. 1846). Alamo & Valdivieso, 1997:18,. fig. 39 (not Phi- lippi, 1846). Page 114 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 Littorina modesta modesta—Vermeij. 1973:324 (not Philip- pi. 1846). Littorina (Littorinopsis) modesta—Abbott, 1974:69 (in part. includes N. modesta). Nodilittorina (? Fossarilittorina) modesta—Reid, 1989a:98, pl. 2. fig. e (in part. includes N. modesta). Skoglund, 1992:16 (not Philippi. 1846). Kaiser, 1997:27 (not Phi- lippi. 1846). Nodilittorina modesta—Finet, 1994:18 (not Philippi, 1846). Taxonomic history: No original type material of Litorina conspersa is known to exist. Nevertheless, there is no doubt as to its identity, since Philippi’s (1847) figure clearly shows the relatively flat whorls and slightly pat- ulous shape, and he accurately described the five grooves on the penultimate whorl and pair of divided ribs near the suture of the last whorl, thus differentiating it from the similar N. modesta. To stabilize the concept of this taxon, a neotype is designated. Philippi (1847) noted that the material from E] Realejo, Nicaragua, on which his description was based, was obtained from Petit. The neo- type is from the same type locality, and was collected by R. B. Hinds on the voyage of the Sulphur (1836-1842). It is possible that Philippi’s material might have originat- ed from this same source, since both Hinds and Petit were in contact with Cuming in London, but there is no direct evidence for this. The types of Litorina puncticulata are lost; it is included in the synonymy of N. conspersa (as first noted by Carpenter, 1857a) because of the four ribs on the penultimate whorl and the presence of a dotted pattern despite the strong sculpture (strongly sculptured N. modesta tend to be white): Philippi’s (1847) descrip- tion of a riblet in each groove on the last whorl could apply to either of the species in the N. modesta group. The longstanding confusion of the names conspersa and modesta has been discussed in the Taxonomic His- tory of N. modesta. Previously. very few authors have recognized more than one species in the N. modesta group in Central America. Philippi (1847: followed by Weinkauff, 1882) recognized three from the single local- ity El Realejo (Nicaragua) and believed a fourth, Litorina modesta, to be from Alaska and Mauritius. His Litorina conspersa was based on elongate, relatively weakly sculptured shells. while Litorina puncticulata was intro- duced for globular, ribbed examples now known to be a Page 115 form of the same species (the third, Litorina albida, was probably an elongate, weakly sculptured form of N. mo- desta; see Taxonomic History of N. modesta). C. B. Ad- ams (1852a. b) likewise separated more and less sculp- tured forms as Littorina puncticulata and L. conspersa (although he noted some intergradation): these were syn- onymized by Carpenter (1863). All subsequent authors recognized only a single species in the region (including Weinkauff, 1883), although von Martens (1900) still used Littorina conspersa var. puncticulata for strongly ribbed shells. Diagnosis: Shell moderately large, spire whorls moder- ately flattened: 4—5 primary spiral grooves: sculpture of incised lines only, or with deep grooves 0.5—1 times rib width: pattern of small orange-brown dots. Tentacles with two longitudinal black lines. Penis with short filament, bluntly hooked at tip. glandular flange at base, no ma- milliform gland. Material examined: 53 lots (including 15 penes, 5 sperm samples, 10 pallial oviducts, 4 radulae). Shell (Figures 7G—K): Mature shell height 4.4—18.2 mm. Shape high turbinate to slightly patulous (H/B = 1.42— 1.65, SH = 1.48—2.07): spire whorls moderately flattened. suture distinct: periphery of last whorl weakly angled. Columella straight, broad, slightly hollowed and pinched (sometimes with slight protruberance) at base: rarely a small imperforate, pseudo-umbilical area: eroded parietal area in larger shells. Sculpture of 4—5 (sometimes 6) pri- mary spiral grooves on spire whorls: these may remain as incised lines only, numbering 8—10 above peripheral rib of last whorl (1 1—14 in total including basal grooves). but usually become slightly wider and deeper toward pe- riphery: grooves rarely become obsolete on shoulder of last whorl; in strongly sculptured shells grooves are deep- er throughout, separating rounded ribs on spire whorls, on last whorl ribs are raised (most strongly so near pe- riphery). rounded, separated by grooves 0.5 to 1 times rib width, narrow interpolated rib may appear in 2 posterior grooves near suture (rarely in all grooves above periph- ery). or occasionally 1—3 posterior ribs become divided by a secondary groove, grooves on last whorl then up to 16 above peripheral rib (up to 23 in total including basal Figure 7. Shells of Nodilitorina modesta (A—F), N. conspersa (G—K), and N. galapagiensis (L—Q). A. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001194). B. Mazatlan, Sinaloa. Mexico (BMNH 20001192). C. 7 km NE of San José del Cabo, Baja California Sur. Mexico (BMNH 20001195). D. Locality unknown (BMNH 20001196). E. Lectotype of Littorina modesta Philippi. 1846: locality unknown (BMNH 1968224/1). FE Bahia Santa Maria, Baja California Sur, Mexico (BMNH 20001187). G. Same, Esmeraldas. Ecuador (BMNH 20001200). H. Tarcoles, Costa Rica (BMNH 20001205). I. Punta Chocolatera. Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001206). J. Neotype of Litorina conspersa Philippi. 1847: El Realejo, Nicaragua (BMNH 19990405/1). K. Bahia Chatham, Isla del Coco, Costa Rica (KLK). L. Holotype of Littorina (Tectarius) galapagiensis Stearns. 1892: Isla Santiago. Galapagos Islands (USNM 102509). M. O, Q. Punta Estrada, Isla Santa Cruz, Galapagos Islands (M. BMNH 20001274; O. BMNH 20001275: Q. BMNH 20001276). N, P. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (N. BMNH 20001273: P. BMNH 20001277). Scale bars A-K = 5 mm; L-Q = 5 mm. Page 116 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 grooves); spiral microstriae absent. Protoconch 0.31 mm diameter, sculptured by spiral ribs. Color white, with pale brown or lilac-grey apex; patterned with small orange- brown (sometimes grey-brown) spots, aligned in oblique (opisthocline) series (commonly less than 16 spots from peripheral rib to suture on last whorl, but up to 26); ap- erture orange-brown with 2 broad pale bands, external spotting showing through near margin; columella orange- brown to purple-brown, pillar sometimes white. Animal (Figure 8L): Head black to pale grey, unpig- mented stripe across black snout, tentacle with two lon- gitudinal black lines, usually meeting close to tip, grey beneath; sides of foot black to pale grey. Opercular ratio 0.32—0.37. Penis (Figures 8G—M): narrow, vermiform; fil- ament short (about 0.25—0.35 total length), with subepi- thelial glandular tissue, bluntly hooked tip, filament dif- ferentiated from base by slight constriction and lack of annular wrinkles (distinction sometimes unclear); sperm groove open to tip; base with fine annular wrinkles except at basal posterior edge with slight glandular flange (opaque subepithelial glandular tissue sometimes visible), base usually slightly pigmented. Euspermatozoa 54-71 jum; paraspermatozoa (Figures 8R, S) round to oval; rod- - pieces single (rarely two), filling cell or projecting, 9-22 wm, blunt, hexagonal in section; granules large, spherical, distinct. Pallial oviduct (Figure 8O) with long straight section; large copulatory bursa opening near posterior end of straight section, extending back to albumen gland; small loop of renal oviduct projects into center of spiral of albumen gland. Spawn not observed; protoconch in- dicates planktotrophic development. Radula (Figure 9C): Relative radular length 3.6—5.1. Rachidian: length/width 1.40—1.50; major cusp elongate, rounded at tip; 2 extra denticles usually present at con- cave anterior edge. Lateral and inner marginal: major cusps elongate rectangular, blunt or rounded at tip. Outer marginal: 8 cusps. Habitat: Rock faces, and among barnacles and mussels; Page 117 in upper eulittoral and low littoral fringe, below level of sympatric N. dubiosa and N. tenuistriata; recorded on basalt, volcanic conglomerate, sandstone, mudstone, and concrete; usually on wave-exposed open coasts, scarce at sheltered and turbid sites. Bakus (1975) recorded it only in protected sites at Isla del Coco. For ecological studies and descriptions of zonation see Markel (1971, includes N. modesta), Cantera et al. (1979), Garrity & Levings (1981), Garrity (1984) (all as Littorina modesta). Range (Figure 10): Oaxaca (Mexico), El Salvador to northern Peru, Isla del Coco and Galapagos Islands. Range limits: Puerto Angel, Oaxaca (BMNH 20001198, 7 specimens); Playa El Cucu, San Miguel, El Salvador (CAS, 4 specimens); Punta Amapala, El Salvador (USNM 780446); Isla del Coco, Costa Rica (BMNH 20001199; KLK); Isla de Malpelo, Colombia (USNM 122854; KLK); Punta San Francisco, Bahia Solano, Co- lombia (USNM 819734); Isla Gorgona and Isla Gorgon- illa, Colombia (USNM 819735); Same, Esmeraldas, Ec- uador (BMNH 20001200); Punta Carnero, Guayas, Ec- uador (BMNH 20001201); 46 km from Caleta Mero, Tumbes, Peru (Alamo & Valdivieso, 1987, 1997); Paita, Piura, Peru (Stearns, 1891); Galapagos Islands (Isla San- tiago, USNM 807235; Isla Santa Cruz, BMNH 20001202; Isla Espanola, BMNH 20001203; Isla San Cristobal, BMNH 20001204). At the most northerly site, Puerto An- gel, this species is much less common than N. modesta. It is relatively frequent in the Galapagos Islands on suit- ably exposed shores and also at Isla del Coco. The ac- curacy of the most southerly record (Stearns, 1891) might be doubted, since the reliability of another in the same publication is questionable (see Range of N. galapagien- SIS). Remarks: See Remarks on N. modesta and Table 2 for discrimination from N. conspersa. Specimens of N. con- spersa from the Galapagos Islands do not appear to differ anatomically from mainland examples, but their shells are slightly more tall-spired than most of the latter, and their Figure 8. Penes (A—M), head pigmentation (A, E, L), pallial oviducts (N, O), and paraspermatozoa (P—S) of Nodilittorina modesta group: N. modesta (A-F, N, P, Q) and N. conspersa (G—M, O, R, S). A, Q. Mazatlan, Sinaloa, Mexico (BMNH 20001192; shell H = 10.0 mm). B. Playa de los Muertos, Puerto Vallarta, Jalisco, Mexico (BMNH 20001197; shell H = 7.8 mm). C, N, P. Bahia Santa Maria, Baja California Sur, Mexico (BMNH 20001187; shell H = 11.6 mm, 12.0 mm). D. Punta Pescadero, Baja California Sur, Mexico (BMNH 20001188; shell H = 11.1 mm). E. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001194; shell H = 6.2 mm). E Puerto Angel, Oaxaca, Mexico (BMNH 20001193; shell H = 12.5 mm). G, J, S. Ballenita, Guayas, Ecuador (BMNH 20001207; shell H = 7.4 mm, 7.7 mm). H, I. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001208; shell H = 5.4 mm, 5.9 mm). K. Punta Estrada, Isla Santa Cruz, Galapagos Islands (BMNH 20001202; shell H = 7.2 mm). L. Puerto Angel, Oaxaca, Mexico (BMNH 20001198; shell H = 9.8 mm). M, R. Same, Esmeraldas, Ecuador (BMNH 20001200; shell H = 10.5 mm). O. Tarcoles, Costa Rica (BMNH 20001205; shell H = 11.2 mm). Abbreviations: p, papilla on penial base; ro, loop of renal oviduct projecting into albumen gland; sg, subepithelial glands in penial base (dotted line; sometimes visible by transparency); sr, seminal receptacle. Shading conventions as in Figures 3, 4. Scale bars A-O = 1 mm; P-S = 20 pm. Page 118 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 Page 119 whorls a little more rounded, which might indicate a de- gree of genetic differentiation of the island populations. The Nodilittorina aspera Group Six species are included in this group: N. aspera, N. tenuistriata, N. dubiosa, N. apicina, N. penicillata, and N. paytensis. Superficially, the shells are very similar, and as a result these are perhaps the most confusing and dif- ficult to identify of the Nodilittorina species of the region. These are medium to large members of the genus, with white to blue-grey shells, usually with a conspicuous dark pattern of axial stripes and, typically, a spiral black line, band or grey zone above the periphery which is promi- nent on the spire whorls, but fades on the last whorl. The aperture is brown, with two pale bands. The sculpture is of spiral grooves, which sometimes become wide and separated by prominent ribs. Not surprisingly, considerable uncertainty has sur- rounded the taxonomy of these species. All but one (N. tenuistriata Reid, sp. nov.) were named before 1864, but this was a fortuitous result of limited availability of ma- terial and lack of appreciation of the range of shell var- iation. The first to be named was Littorina aspera Phi- lippi, 1846, followed by Litorina paytensis Philippi, 1847. In 1851 Menke provisionally named Litorina ap- icina, but was unwilling to separate it as a distinct spe- cies from L. aspera in the same collection from Maza- tlan. With a larger volume of material from Mazatlan at his disposal, Carpenter (1857b) correctly distinguished two species in this complex, L. aspera and L. philippii (= N. apicina) and later (1864a) described Littorina penicillata as a variety of the latter. Meanwhile, C. B. Adams (1852a, b) used the name Littorina aspera for large ribbed shells from Panama, whereas smaller smooth shells (now known to be conspecific) were doubtfully identified as L. parvula (a nomen dubium in- troduced by Philippi, 1849) and provisionally renamed L. dubiosa. Thus several early authors recognized two species in the complex, a ribbed form named aspera and a smaller, smoother shell variously named apicina, du- biosa, parvula, or philippii. In Mexico (Menke, 1851; Carpenter, 1857b, 1864a) this distinction did indeed cor- respond to that now made on anatomical grounds be- tween N. aspera and N. apicina. However, the intraspe- cific variation in size and sculpture was not appreciated and therefore farther south in Central America (where N. apicina is rare) the names aspera and dubiosa/par- vula/philippii were applied to rough and smooth ex- tremes of the single common species (for which the val- id name is N. dubiosa) (C. B. Adams, 1852a, b; Car- penter, 1863). This distinction of two species contrasting in sculpture was continued in systematic revisions by Weinkauff (1882), von Martens (1900), and Keen (1958), in which aspera was applied to ribbed shells of both N. aspera and N. dubiosa, whereas philippii/dubio- sa included a range of smoother forms (N. apicina, N. penicillata, N. dubiosa, and even N. modesta and N. in- terrupta). There was, however, an alternative tendency to combine these variable and troublesome shells as a single species, for which the earliest name aspera was employed (Weinkauff, 1883; Tryon, 1887; Keen, 1971; Abbott, 1974). Tryon (1887) even included the N. mo- desta group under the specific name aspera. In the lit- erature of the past 30 years there has been no attempt to revise the N. aspera group, despite the observation by Keen (1971) that careful study might reveal a com- plex of species. The faunistic lists of areas of Mexico, Central America, and the Galapagos that appeared dur- ing the twentieth century have almost all listed only as- pera (Biolley, 1907; Morrison, 1946; Hertlein, 1963; Montoya, 1983; Finet, 1985, 1994; Holguin & Gonzalez, 1989; Emerson, 1995; Kaiser, 1997), although an excep- tion was that of Pilsbry & Lowe (1932) in which the names aspera, penicillata, and philippii were listed. Cu- riously, the predominantly southern species N. paytensis has sometimes been recognized as distinct in revisions and worldwide lists (Weinkauff, 1882, 1883; Rosewater, 1970; Keen, 1971), and in the Peruvian literature (Ve- gas, 1968; Pena, 1971b; Alamo & Valdivieso, 1987, 1997; Paredes et al., 1999), despite its close resemblance to other members of the N. aspera group. If synony- mized at all, it was combined with another (but not closely related) southern species, N. araucana (Tryon, 1887; Dall, 1909; Hertlein & Strong, 1955b; Reid, 1989a; Finet, 1994), or doubtfully reduced to a subspe- cies of N. modesta (Keen, 1971; Vermeij, 1973; Finet, 1985). The other southern species in the N. aspera group, N. tenuistriata Reid, sp. nov., has hitherto ap- peared only in Peruvian literature, identified as Littorina aspera (Alamo & Valdivieso, 1987, 1997; Paredes et al., Figure 9. Radulae of Nodilittorina modesta (A, B), N. conspersa (C), N. dubiosa (D), N. aspera (E, F), N. tenuistriata Reid, sp. nov. (G), and N. penicillata (H). A, B. Bahia, Santa Marfa, Cabo San Lucas, Baja California Sur, Mexico (BMNH 20001187; two views of radula, flat and at 45°; shell H = 10.9 mm). C. Ballenita, Guayas, Ecuador (BMNH 20001207; at 45°; shell H = 7.9 mm). D. Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001229; at 45°; shell H = 11.3 mm). E, E Puerto Marques, Acapulco, Guerrero, Mexico (BMNH 20001217; two views of radula, flat and at 45°; shell H = 11.3 mm). G. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001223; at 45°; shell H = 11.2 mm). H. San Felipe, Baja California Norte, Mexico (BMNH 20001250; at 45°; shell H = 8.2 mm). Scale bars = 50 pm. Page 120 The Veliger, Vol. 45, No. 2 120° 110° 100° 90° 2 °. 40° 80' 70 30° 20° 10° o° o N. modesta e@ N. conspersa A Alamo & Valdivieso (1987, 1997) B Stearns (1891) 10° 120° 110° 100° 90° 80° 70° Figure 10. Geographical distribution of Nodilittorina modesta group (records based on material examined and quoted literature sources). D. G. Reid, 2002 1999). In the two most recent worldwide lists of species of Littorinidae, Rosewater (1970) included Littorina as- pera, L. penicillata, and L. paytensis, whereas Reid (1989a) gave only N. aspera, with N. penicillata and N. paytensis both of doubtful status. As in the other species complexes of Nodilittorina, the crucial observations leading to discrimination of these difficult taxa have been the discovery of sympatric and syntopic occurrences, localities at which the distinctive shell types co-occur on rocks on the shore (though often at slightly different levels within the uppermost eulittoral and littoral fringe). At the southern tip of Baja California three species co-occur (N. aspera, N. apicina, N. penicil- lata); in southern Mexico two (N. aspera, N. apicina); in Nicaragua four (NV. aspera, N. tenuistriata, N. dubiosa, N. apicina); in Costa Rica four (N. tenuistriata, N. du- biosa, N. apicina, N. paytensis); and in Ecuador three (N. tenuistriata, N. apicina, N. paytensis). Correlated with these shell types are differences in the shape of the penis, but these are more subtle than is often the case in litto- rinids, and are not always diagnostic. Other anatomical features, such as the paraspermatozoa and copulatory bur- sa, also provide discriminating characters in some cases, “but radulae do not. The most useful characters for iden- tification of species in this complex are summarized in Table 3. Another key to the understanding of the N. aspera complex is the recognition that the strength of shell sculp- ture is variable in most species; that is, the width and depth of the spiral grooves varies, although their number is more constant. Early authors identified those large shells with strong ribs and wide grooves as aspera, and separated smaller smoother forms as apicina, philippii, parvula, and dubiosa, as discussed above. In fact, most species (except N. tenuistriata) can show almost com- pletely smooth shells in dwarf or stunted forms, and strong spiral ribs are seen only on the last whorl of large examples of N. aspera and N. dubiosa. Surprisingly, in this group, shell color pattern is a more reliable guide for rapid identification in the field (Table 3), although in other members of the genus (e.g., N. porcata group) this is variable. The intensity of the dark pattern does neverthe- less show variation and is especially dark in dwarf shells, which can be found for example in saline pools high in the eulittoral zone. As in the N. porcata group, it is sug- gested that this may be a case of ecophenotypic variation (see Discussion). There is a parallel between the N. aspera group and the complex of black and white shells (informally known as the N. ziczac group) found in the Caribbean and west- ern Atlantic, which consists of at least four (Reid, 1989a) or as many as six (Bandel & Kadolsky, 1982) species. Whether they share common ancestry is not yet known. When the origin of specimens is not known, confusion can arise; for example, von Martens (1900) erroneously described a Caribbean species (N. interrupta) as Littorina Page 121 philippii var. latistrigata, believing it to have originated from the Pacific coast of Costa Rica. Nodilittorina aspera (Philippi, 1846) (Figures 9E, F 11A—H, 13A—E 15A, J, K, 17) Littorina aspera Philippi, 1846a:139 (Sitka, New Albion [Alaska]; Mexico; Conchagua, San Salvador [El Sal- vador]; here restricted to Mazatlan, Mexico; lectotype (here designated, 16.6 x 10.9 mm) BMNH 1968217/1, seen, Figure 11A; 3 paralectotypes BMNH 1968217/2, seen). Middendorff, 1849:394. Carpenter, 1857a:162, 216, 224, 286. ? Troschel, 1858:135, pl. 11, fig. 4 (rad- ula). Keen, 1958:282, ? fig. 173 right (in part, includes N. dubiosa). Keen, 1971:365, fig. 181 (part) (in part, includes N. apicina, N. penicillata, N. dubiosa, N. mo- desta, N. interrupta). Holguin & Gonzalez, 1989:114, fig. Litorina aspera—Philippi, 1847:2:200 (in part, fig. is N. du- biosa). Menke, 1851:163—164 (in part, includes N. ap- icina). Carpenter, 1857a:235, 237, 257, 326, 348 (in part, includes N. dubiosa). Carpenter, 1864b:623 (in part, includes N. dubiosa). Weinkauff, 1882:60—61 (in part, figs. are N. dubiosa). Weinkauff, 1883:220 (in part, includes N. apicina, N. dubiosa, N. penicillata). Car- penter, in Brann, 1966:pl. 38, fig. 397. Littorina (Melaraphe) aspera—H. & A. Adams, 1854:314. von Martens, 1900:577, 587, ? pl. 43, fig. 15 (in part, includes N. dubiosa, N. apicina). Tryon, 1887:249, pl. 45, fig. 87 (in part, includes N. modesta, N. conspersa, N. apicina, N. penicillata). Litorina (Melaraphe) aspera—Carpenter, 1857b:348—349 (includes N. dubiosa). Littorina (Austrolittorina) aspera—Rosewater, 1970:423. Abbott, 1974:69, fig. 561, pl. 3, fig. 561 (in part, in- cludes N. dubiosa, N. apicina, N. penicillata). Nodilittorina (Nodilittorina) aspera—Reid, 1989a:99 (in part, includes N. dubiosa, possibly N. penicillata). Sko- glund, 1992:15 (in part, includes N. dubiosa, possibly N. penicillata). Nodilittorina aspera—Emerson, 1995:13. Littorina irrorata—Reeve, 1857:sp. 56, pl. 11, fig. 56a, b (not Turbo irroratus Say, 1822 = Littoraria irrorata). Taxonomic history: Of the three collections mentioned by Philippi (1846a) in the original description of aspera, only that from Sitka has been located, but the locality is obviously erroneous (Carpenter, 1857a). Philippi appar- ently included the closely similar southern species N. du- biosa in his concept of the taxon, since his figure (Phi- lippi, 1847) of N. aspera appears to represent N. dubiosa. To fix the concept of this taxon, a lectotype is designated from the extant syntypes, and the type locality is here restricted to Mazatlan. This species was the first of the N. aspera group to be described and the name has remained one of the most familiar in the eastern Pacific fauna. Examples of this species have never been figured or described under any other name, with the exception of Reeve’s (1857) “Lit- torina irrorata’’ (an error first noted by von Martens, 1900). Nevertheless, most authors have had too broad a The Veliger, Vol. 45, No. 2 Page 122 UINIPOU OF [[RUUS d3.1e] 0} WUNTpoU pojurod ‘SuLiody) ‘popu sJop UMOIG pospnus Aroydiiod aaoqge purq uMOIg prog quonbaly Soul] pesfoul E€7—-TT WYsreys 1yste.ys nad N 0} Bory v1sop 2qo| e SUTUIOJ ‘WINIpoUl UINTpoul pojurod ‘yJOOUIS “peo.ig soul] PaarM 10 anbijqo Axsaydiiad MO]Aq | pur dAOge OUI, MOLILU | IRI Soul] PSSTOUL [1-8 dAvOUOd WYse.ns erUsOJeD JO FIND ‘vIUIOs ED vleg § 3qo| B SUIUIOJ “WUNIpow uInIpoul suliode} ‘popULIM ‘Suo] uoneyassay Jo ‘sodiys 10 souly B8ezSIz 10 onbijgo Aroydiiod aa0qe ouoz Adis JOUNSIpUl O11 (yIpIm qli Jyey 0} Ayo.) SOAOOIS MOLICU IO SOUL] PASIOUl T[—6 WYsIeNs ‘Suoy XdAU0d Jopenoyq N oO} PIUIOFTeD vleg UIMIPOW O} []BUUS IS1P] Pee te) uINnIpouw suliodr} ‘yjoous ‘pro4qg Suliode) ‘popyuLim sodiys anbijqo MoeU soul [erxe anbiygo Asoydiiad Mojaq our ‘Araydiiod dAOQgR JUOZ AdI5-on][q peo.iq SULIO} pojun}s ut Ayurew SOUT] POSTOUL 10 (YIPIM QU 95IM4 0} dn) soaois apim daap | [-L dAvoUu0d dAROUOD JO ]YSIe.S A1roydiiod MOlAq pug yoryq ‘Atoydiiad aaoqe purq xorg prog juosqe (Aroydiiod yw squi St YIPIM OWS 0} dn) sda0o0i3 ¢{[—-O] dARIUOD 1Yys1e.1s S] sosedryey ‘000g [ep BIS] “BIquio] -OD 0} JOpRATeS [qs NDg_ NO} UNSLILIIN uInIpour unIpou Sutiodr) ‘yOours sods onbijqo Apysiys Axoydiiad MO]OQ OUI] yoryq ‘aids uo Araydiiad aaoqe purg yoryq prog SULIOJ PajuNys Ul (WIPIM qi soul € 0) dn) saaoco13 apim daap Q[-L dAvIUOD dAvouod ens -BIBOIN ‘OOTXOJAL S 0} BIUIOJITeD eleg ¢ OSIp Jejnpurys— puvys wos ypruueu— qUSUIe] y— studg usoyyed [erxe— (sjtoyM outds uo jsoylep AyTyensn) spurq [eds y1ep— WAOJ YJOOUS— [roym ysey Jo Araydiiad DAOQR S9AOO.1S— eyjaumN,;oo— ajyoid a1rds— IISus asuri [eorydeis0ayH fon] sisuajapd “NJ DIY pPloiuad “AJ puizidp “ny psoiqnp "N DIDIASINUA] “A piadsp “N TooeVIey) ‘dnois psadsp puisojjipIpoN yy JO satoads XIs dy} JO UONRIYNHUSp! OY} OJ s1aJORIeYS [NJosn jsow oy} Jo Areurwinsg © SI9RL D. G. Reid, 2002 rage 123 concept of this taxon, including with it various others from the N. aspera complex. In the early literature, most authors discriminated two species in the complex, one larger and more strongly sculptured (to which the name aspera was applied), the other smaller and relatively smooth (see Taxonomic History of N. apicina and N. pen- icillata). For the first time, it is shown here that the larger, more sculptured shells comprise three species, N. aspera s.s., N. dubiosa, and N. tenuistriata. Of these, the last is relatively uncommon in Central America and has been specifically referred to (as aspera) only in the Peruvian literature (Alamo & Valdivieso, 1987, 1997; Paredes et al., 1999). The other two have, however, been widely confused, although their largely allopatric distribution as- sists when synonymies are compiled (see also Taxonomic History of N. dubiosa). The use of the name aspera for all species in the N. aspera group, regardless of sculpture and size, dates from Weinkauff (1883) and Tryon (1887, who also included the N. modesta group). This practice was followed by Keen (1971), Abbott (1974), and Reid (1989a). Diagnosis: Shell large, spire whorls slightly rounded, - spire profile often slightly concave; 5—7 primary spiral grooves; 7-10 grooves above periphery of last whorl; sculpture of deep grooves up to 3 times rib width on last whorl of large shells, but only incised lines on small shells; white with brown axial stripes and (most obvious on spire whorls) broad spiral black band just above pe- riphery. Penis with gradually tapering filament; mamilli- form gland and glandular disc of similar size, on promi- nent projection of base. Material examined: 47 lots (including 23 penes, 2 sperm samples, 4 pallial oviducts, 4 radulae). Shell (Figures 11A—H): Mature shell height 5.0—22.0 mm. Shape high turbinate (H/B = 1.27—1.83, SH = 1.43-— 2.00); spire whorls slightly rounded, suture distinct; spire profile usually slightly concave, giving slight onion shape; periphery of last whorl weakly angled. Columella concave, hollowed and slightly pinched at base; small eroded parietal area. Sculpture of (4) S—7 primary spiral grooves on spire whorls; ribs subequal, or slightly wider at suture and periphery; 7-10 grooves above periphery of last whorl, secondary sculpture usually absent, but rarely 1—2 narrow secondary ribs develop posteriorly; on last whorl grooves enlarge to 1—3 times width of intervening ribs, which become narrow, sharply raised cords; in dwarf forms, the typical wide grooves do not develop, grooves remain as impressed lines, or become faint; spiral mi- crostriae absent. Protoconch 0.31 mm diameter, 2.5 whorls. Color white, with slightly oblique or waved axial brown stripes; on lower half of spire whorls a broad grey to black spiral band; on last whorl axial pattern may be- come less distinct except at suture, and broad grey band above periphery may also become faint; a narrow black band is also present on base just below periphery; dwarf shells (Figure 11B) usually show striking pattern of black axial stripes and band above and below periphery; aper- ture brown, with 2 pale spiral bands at base and shoulder; columella brown. Animal: Head grey to black, no unpigmented stripe across snout, tentacle pale at base and around eye, with two longitudinal black stripes, and black spot at tip; sides of foot pale grey to black. Opercular ratio 0.33—0.40. Pe- nis (Figures 13A—F): filament moderately long, gradually tapering, smooth, thickened and glandular at base, 0.6— 0.8 total length; sperm groove open to tip; mamilliform gland and glandular disc of similar size, on well devel- oped projection of base; penis unpigmented or only slightly pigmented at base. Euspermatozoa not seen; par- aspermatozoa (Figures 15J, K) 18-20 pm, oval, with large round granules, single stout rod-pieces (sometimes composed of smaller rod-shaped elements) fill cells or project slightly. Pallial oviduct (Figure 15A) with large copulatory bursa opening at half length of straight section and extending back to albumen gland. Spawn not ob- served; protoconch indicates planktotrophic development. Radula (Figures 9E, F): Relative radular length 10.2— 15.7. Rachidian: length/width 1.50-1.79; major cusp elongate, rounded at tip. Lateral and inner marginal: ma- jor cusps elongate, rounded at tip. Outer marginal: 7—9 cusps. Habitat: Clustered in crevices and on bare rock in littoral fringe; above water level at margins of shallow pools at top of eulittoral; largely restricted to exposed and mod- erately exposed coasts in oceanic situations; recorded on granite and concrete; usually abundant. Overlapping with N. apicina, but extending farther into littoral fringe. Range (Figure 17): Southwestern Baja California to Oa- xaca (Mexico), Islas Revillagigedo, Nicaragua. Range limits: Laguna San Ignacio, Baja California Sur (USNM 130599, 1 specimen); Bahia Magdalena, Baja California Sur (USNM 264566, 819879, 1 specimen each); Punta Lobos, Todos Santos, Baja California Sur (personal ob- servation); 7 km N of San José del Cabo, Baja California Sur (BMNH 2001209); Punta Doble, Sonora (KLK, 1 specimen); Topolobampo, Sinaloa (BMNH 20001210, 1 specimen); Mazatlan, Sinaloa (BMNH 20001211); Bahia Ventosa, Golfo de Tehuantepec, Oaxaca (USNM 60449, 4 specimens); Salina Cruz, Golfo de Tehuantepec, Oaxaca (LACM 67-97-30, 3 specimens); Bahia Henslow, Isla So- corro, Islas Revillagigedo (KLK, | specimen); Corinto, Nicaragua (LACM 149775, 149776, 1 and 6 specimens); Nicaragua (CAS 122365, 2 specimens). This species is apparently very rare in the Gulf of California, from which only two specimens are known. It is, however, common on the southwestern coast of Baja California and from Mazatlan southward. Material from Nicaragua is scarce in collections; the two lots in LACM are apparently re- Page 124 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 liable and further supported by von Martens’ (1900) fig- ure of a specimen from El Salvador. Only a single spec- imen has been seen from Isla Socorro, although the name appears in lists from the island (Mille-Pagaza et al., 1994; Emerson, 1995). Remarks: Since the original description of this species (Philippi, 1846a; see Taxonomic History above) the name has been applied to all large eastern Pacific littorinids with sharp ribs separated by wide grooves, and therefore also included large shells of N. dubiosa (distributed from El Salvador to Colombia). This similarity is, however, superficial and there are small but consistent differences in shell coloration, penial anatomy and habitat (see Re- marks on N. dubiosa). The new species N. tenuistriata is separated from N. aspera by its finer sculpture (7—10 pri- mary spiral grooves on spire whorls, 10-15 narrow grooves above periphery of last whorl), but similarities in shell coloration, paraspermatozoa, and habitat suggest a close relationship (see Remarks of N. tenuistriata). The known geographical distribution of N. tenuistriata just meets that of N. aspera at Corinto (Nicaragua) and ex- tends to Peru; their distinguishing shell characters remain “distinct at the one known locality of sympatry. The distinctive coloration of N. aspera remains rather constant throughout its range. However, adult size varies widely and only shells of moderate and large size develop the strong sculpture of narrow ribs by which this species (together with N. dubiosa) has previously been charac- terized. Dwarf specimens (Figure 11B) are found in shal- low pools at the top of the eulittoral zone, and in these small shells the sculpture is weak or almost absent. Dwarf specimens show a striking black pattern on a white ground. Similar variation is seen in dwarf examples of WN. apicina from the same microhabitat; in both species oc- casional shells show an abrupt change to a more normal sculpture and pattern, implying an ecophenotypic com- ponent to the variation. The radula is extraordinarily long, sometimes exceed- ing 15 times the length of the shell. Page 125 Nodilittorina tenuistriata Reid, sp. nov. (Figures 9G, 11I-O, 13G-L, 15B, L, M, 17) Littorina (Austrolittorina) aspera—Alamo & Valdivieso, 1987:25, fig. 35. Alamo & Valdivieso, 1997:17, fig. 35. Paredes et al., 1999:22. (All not Philippi, 1846). Etymology: Latin: “‘finely striated,’ describing the char- acteristic sculpture. Types: Holotype BMNH 20000312 (Figure 111). 28 par- atypes BMNH 20000310 (Figure 11L, M). 100 paratypes BMNH 20000314 (ethanol). 4 paratypes USNM 894293. Type locality: Punta Chocolatera, Peninsula Santa Elena, Guayas Province, Ecuador. Taxonomic history: This species has been almost entire- ly ignored in the literature. It has a wide distribution from Nicaragua to Peru. However, in Central America it is rel- atively uncommon, and no authors working in the area have distinguished it from the abundant N. dubiosa, whereas the littorinids of Colombia and Ecuador have scarcely been studied. Only in Peru (where N. dubiosa does not occur) has this species been specifically referred to, and then identified as aspera (Alamo & Valdivieso, 1987, 1997; Paredes et al., 1999). Von Martens (1900) introduced the name Littorina phi- lippii var. latistrigata for shells superficially similar to this species, white with oblique black axial stripes and spiral black band, although the sculpture was described as faint. The type locality was given as Punta Arenas, western Costa Rica. Examination of two syntypes in MNB has confirmed that they belong to the Caribbean species N. interrupta, characterized by waved or zigzag axial stripes, fine or obsolete sculpture, and raised dark brown inner lip of the aperture adjacent to the columella. Von Martens’ type locality must be regarded as errone- ous, but the species does occur on the eastern coast of Costa Rica. Diagnosis: Shell large or small, whorls moderately rounded or slightly shouldered, spire profile usually Figure 11. Shells of Nodilittorina aspera group: N. aspera (A—-H), N. tenuistriata Reid, sp. nov. (I-O), and N. dubiosa (P-Z). A. Lectotype of Littorina aspera Philippi, 1846; locality unknown (BMNH 1968217/1). B, G. Bahia Santa Maria, Baja California Sur, Mexico (BMNH 20001212). C, E, H. Puerto Angel, Oaxaca, Mexico (C, H, BMNH 20001213; E, BMNH 20001214). D. Boca de Tomatlan, Jalisco, Mexico (BMNH 20001215). E Playa de los Muertos, Puerto Vallarta, Jalisco, Mexico (BMNH 20001216). I. Holotype of N. tenuistriata Reid, sp. nov.; Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 2000312). J, O. Tarcoles, Costa Rica (BMNH 20001224). K. Muisne, Esmeraldas, Ecuador (BMNH 20001125). L, M. Paratypes of N. tenuistriata Reid, sp. nov.:; Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000313). N. Same, Esmeraldas, Ecuador (BMNH 20001226). P. Isla San José, Islas Perlas, Panama (USNM 588051). Q. Punta Pitt, Isla San Cristobal, Galapagos Islands (BMNH 20001227). R. Coco, W of Liberia, Costa Rica (BMNH 20001228). S. San Juan del Sur, Nicaragua (USNM 23304). T, Y. Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001229). U. Nicaragua (USNM 46973). V. Isla San José, Islas Perlas, Panama (USNM 587787). W. Bahia Chatham, Isla del Coco, Costa Rica (KLK). X. Tarcoles, Costa Rica (BMNH 20001230). Z. Lectotype of Littorina dubiosa C. B. Adams, 1852; Isla Taboga, Panama (MCZ 186573). Scale bar = 5 mm. The Veliger, Vol. 45, No.2 Page 126 D. G. Reid, 2002 RagemlZ7/ straight; 7-10 primary spiral grooves; 10—15 grooves above periphery of last whorl; sculpture of numerous fine grooves (10-15 above periphery of last whorl); white with oblique, grey-brown, axial lines and broad spiral grey to black band just above periphery (indistinct on last whorl). Penis with wrinkled filament roundly tapered at tip; mamilliform gland and large glandular disc borne on long projection of base. Material examined: 31 lots (including 17 penes, 9 sperm samples, 4 pallial oviducts, 5 radulae). Shell (Figures 11I—O): Mature shell height 5.0—19.6 mm. Shape high-turbinate to elongate (H/B = 1.39-1.78, SH = 1.47-1.95); spire whorls moderately rounded, su- ture distinct; spire profile usually straight, sometimes slightly concave; last whorl slightly shouldered, periphery angled. Columella concave, hollowed, and _ slightly pinched at base; eroded parietal area. Sculpture of 7—10 primary spiral grooves on spire whorls; primary ribs sub- equal, slightly wider toward suture; 10-15 (17) grooves above periphery of last whorl; peripheral rib raised and twice as wide as ribs above and below; secondary sculp- -ture may be absent, or single narrow secondary riblets appear in grooves near suture and periphery; sculpture never becomes obsolete; on last whorl grooves close to periphery enlarge to 0.5—1 times width of intervening ribs, but others remain narrow; spiral microstriae absent. Protoconch not seen. Ground color white to pale blue- grey, with oblique brown, grey, or black stripes, inter- rupted by broad grey to black spiral band just above pe- riphery and another on base; spiral bands become paler on last whorl, remaining as blue-grey zones; in dwarf forms (Figure 11M) a striking pattern of black stripes and bands on white ground; aperture brown, external pattern showing through, with 2 pale spiral bands at base and shoulder; columella brown. Animal: Head grey to black, no unpigmented stripe across snout, tentacle pale around eye and sometimes at inside of base, with two longitudinal black stripes meet- ing at black tip; sides of foot grey or black speckled. Opercular ratio 0.34—0.40. Penis (Figures 13G—L): fila- ment moderately long, tapering toward rounded tip, with annular wrinkles on lower half, glandular, 0.6—0.8 total length; sperm groove open to tip; glandular disc large (usually larger than mamilliform gland), projecting as a lobe, borne with mamilliform gland on long projection of base (as long as filament, in well relaxed specimens); pe- nis unpigmented or only slightly pigmented at base. Eus- permatozoa 54—75 jm; paraspermatozoa (Figures 15L, M) oval with single (sometimes 2—3 if narrow) blunt or rounded rod, 10—34 wm, projecting from cell, cytoplasm packed with large spherical granules. Pallial oviduct (Fig- ure 15B) with large copulatory bursa opening at half length of straight section and extending back to albumen gland. Spawn not observed. Radula (Figure 9G): Relative radular length 3.6—7.7. Rachidian: length/width 1.38—1.64; major cusp elongate, rounded at tip. Lateral and inner marginal: major cusps elongate, rounded at tip. Outer marginal: 6—7 cusps. Habitat: Common on cliffs on exposed oceanic coasts; in littoral fringe, especially at sites of freshwater seepage; rare on rocks and piers on sheltered or muddy coasts; recorded on volcanic conglomerate, sandstone, mudstone, soil, concrete. Variously microsympatric with N. dubiosa, N. apicina, and N. paytensis in different parts of its range, but extends higher up the shore than these. Range (Figure 17): Nicaragua to northern Peru. Range limits: Corinto, Nicaragua (LACM 149776, 1 specimen); Playa del Coco, Costa Rica (G. J. Vermeij Collection); Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001220); Fort Amador, Panama (USNM 732997, 1 specimen); Isla Gorgona, Colombia (USNM 819732, 3 specimens); Atacames, Esmeraldas, Ecuador (BMNH 20001221); Peninsula Santa Elena, Guayas, Ecuador (Punta Chocolatera, BMNH 20000314; Anconcito, BMNH 20001222); Paita, Piura, Peru (Alamo & Valdi- vieso, 1987, 1997; as Littorina aspera). This species is moderately common in Costa Rica, but much more so in Ecuador. Only a single specimen has been recorded from Figure 12. Shells of Nodilittorina aspera group (continued): N. apicina (A—l), N. penicillata (J-Q), and N. pay- tensis (R—BB). A. Same, Ecuador (BMNH 20001236). B. Lectotype of Litorina philippii Carpenter, 1857; Mazatlan, Sinaloa, Mexico (BMNH 1857.6.4.1682/1). C, E. Puerto Marques, Acapulco, Guerrero, Mexico (BMNH 20001237). D. Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001238). E Lectotype of Litorina apicina Menke, 1851; Mazatlan, Sinaloa, Mexico (SMF 314713/4). G. Boca de Tomatlan, Jalisco, Mexico (BMNH 20001239). H. La Manzanilla, 10 km N of Melaque, Colima, Mexico (BMNH 20001240). I. Atacames, Esmeraldas, Ecuador (BMNH 20001235). J, M, Q. Topolobampo, Sinaloa, Mexico (BMNH 20001247). K. Cabo San Lucas, Baja California Sur, Mexico (BMNH 20001244). L. Lectotype of Litorina penicillata Carpenter, 1864; Cabo San Lucas, Baja California Sur, Mexico (USNM 4058). N—P. San Felipe, Baja California Norte, Mexico (BMNH 20001245). R. Punta Carnero, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001256). S—U. Ballenita, Guayas, Ecuador (BMNH 20001257). V. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001252). W. Mancora, Peru (USNM 663988). X. Muisne, Esmeraldas, Ecuador (BMNH 20001258). Y-—AA. Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001259). BB. Lectotype figure of Litorina paytensis Philippi, 1847; Paita, Peru (Philippi, 1847: Litorina pl. 3, fig. 25). Scale bar = 5 mm. D. G. Reid, 2002 Page 129 Panama despite abundant littorinid collections from the area. Remarks: This species shows a range of shell variation comparable with that seen in N. aspera and N. apicina; dwarf specimens are not only smaller but also show weaker sculpture, a striking black and white color pattern, and a slightly convex (domed) profile (Figure 11M). Some large specimens show early whorls of this dwarf form (Figure 11L; note change in spire profile and col- oration), suggesting that ecophenotypic plasticity may be responsible. Habitat details for dwarf forms are lacking, but by analogy with these other species it is likely that they are found in unfavorable conditions, such as pools with fluctuating salinity high on the shore. Dwarf forms are presumably produced when growth is slow, whereas rapid growth results in shells that are paler, with concave spire profile and larger adult size. For much of its range, N. tenuistriata is sympatric with N. dubiosa, and there is therefore no doubt that these two are distinct (for discrimination, see Remarks on N. du- biosa). Their typical habitats differ, N. tenuistriata being more frequent on exposed coasts, and N. dubiosa on rel- atively sheltered shores; nevertheless, they can be micro- sympatric on shores of moderate exposure, for example in Costa Rica. Interestingly, this species is very rare in the Gulf of Panama, possibly connected with eutrophic conditions there. This species exhibits an oceanic type of distribution. Curiously, on oceanic coasts it is most abun- dant at the very top of the shore where there is freshwater seepage from cliffs or hillsides. Its relationship to N. aspera, recorded from Mexico to Nicaragua, is more problematic. The shell shape, size, and color pattern (with a broad peripheral dark band, es- pecially on spire and in dwarf shells) are closely similar. Nevertheless, all shells (including dwarf forms) can be readily separated by their sculpture, which is of finer and more numerous grooves in N. tenuistriata (7-10 primary grooves on spire whorls, 10-15 narrow grooves above periphery of last whorl) than in N. aspera (5-7 primary grooves on spire whorls, 7-10 wide grooves above pe- riphery of last whorl). Anatomically, there is a small, but apparently consistent, difference in the penis; the filament of N. tenuistriata bears annular wrinkles; it is also less obviously tapering than in N. aspera and the basal pro- jection is often longer. The relative radular length is con- siderably greater in N. aspera (but this may be subject to variation according to rate of wear and requires further study). The paraspermatozoa are similar (although since most of the available specimens of N. aspera were im- mature, few sperm cells have been seen). Both species show a preference for exposed oceanic coasts. The sim- ilarities suggest a close relationship, and the differences could possibly be explained by geographical variation within a single species. However, a single sample has been seen from Corinto (Nicaragua; LACM 149776) which contains six examples of typical N. aspera and one shell tentatively identified as N. tenuistriata. This shell is atypical, lacking the dark spiral band and showing a slightly convex profile; neverthless, the large size (16.7 mm), white ground color, and fine sculpture apparently preclude any other species. The resemblance is closest to some shells of N. tenuistriata from the nearest known localities to the south, in Costa Rica (Figure 110). In any case, this shell (and its sympatric N. aspera) gives no suggestion of a merging of the shell characters of the two forms at this point of contact of their ranges. For these reasons, the two are believed to be distinct, although fur- ther sympatric records and genetic evidence are desirable to test this conclusion. A commensal polyclad flatworm was found in the man- tle cavity of one specimen (Punta Chocolatera, Guayas, Ecuador; BMNH), as also reported here for N. modesta, N. conspersa, and N. apicina. Nodilittorina dubiosa (C. B. Adams, 1852) (Figures 9D, 11P—Z, 13M-—Q, 15C, I, N, 17) Litorina aspera—Philippi, 1847:2:200, Litorina pl. 4, fig. 13 (in part, includes N. aspera). Carpenter, 1857a:230, 326 (in part, includes N. aspera). Carpenter, 1864b:623 (in part, includes N. aspera). Weinkauff, 1882:60—61, pl. 8, figs. 2, 3 (in part, includes N. aspera). Weinkauff, 1883:220 (in part, includes N. aspera, N. apicina, N. penicillata). Littorina aspera—C. B. Adams, 1852a:394—395 (in part, in- Figure 13. Penes of Nodilittorina aspera group: N. aspera (A-F), N. tenuistriata Reid, sp. nov. (G—L), and N. ' dubiosa (M-Q). A, B. Puerto Marques, Acapulco, Guerrero, Mexico (BMNH 20001217; shell H = 10.6 mm, 11.3 mm). C, E Cabo San Lucas, Baja California Sur, Mexico (BMNH 20001218, shell H = 8.9 mm, 10.2 mm). D, E. Puerto Angel, Oaxaca, Mexico (D, BMNH 20001213; shell H = 11.1 mm; E, BMNH 20001214, shell H = 12.7 mm). G, H. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001223; shell H = 12.9 mm, 10.5 mm). I. Muisne, Esmeraldas, Ecuador (BMNH 20001225; shell H = 11.7 mm). J, L. Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20000314; shell H = 5.0 mm, 11.3 mm). K. Atacames, Esmeraldas, Ecuador (BMNH 20001221; shell H = 10.3 mm). M. Tarcoles, Costa Rica (BMNH 20001230; shell H = 10.5 mm). N. Paitilla Beach, Panama City, Panama (USNM 733196; shell H = 9.5 mm). O. Coco, W of Liberia, Costa Rica (BMNH 20001228; shell H = 3.9 mm). P, Q. Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001229; shell H = 11.3 mm, 8.6 mm). Abbreviation: pgd, penial glandular disc (stipple). Shading conventions as in Figure 3. Scale bar = 1 mm. D. G. Reid, 2002 cludes N. aspera). C. B. Adams, 1852b:170—171 (in part, includes N. aspera). Carpenter, 1857a:186, 273 (not Philippi, 1846). Merch, 1860:69 (not Philippi, 1846). Carpenter, 1863:352 (in part, includes N. as- pera). Biolley, 1907:23 (not Philippi, 1846). Morrison, 1946:10 (not Philippi, 1846). Keen, 1958:282, fig. 173 left (in part, includes N. aspera). Hertlein, 1963:239 (as aspersa; not Philippi, 1846). Keen, 1971:365, fig. 181 (part) (in part, includes N. aspera, N. penicillata, N. apicina, N. modesta, N. interrupta). Montoya, 1983:332 (in part, includes N. aspera). Littorina (Melarhaphe) aspera—von Martens, 1900:577, 587, ? pl. 43, fig. 16 (in part, includes N. aspera, N. apicina). Littorina (Austrolittorina) aspera—Abbott, 1974:69 (in part, includes N. aspera, N. apicina, N. penicillata). Nodilittorina (Nodilittorina) aspera—Reid, 1989a:99, fig. 11k (egg capsule) (in part, includes N. aspera). Kaiser, 1997:27. Nodilittorina aspera—Finet, 1994:18. Littorina parvula ?.—C. B. Adams, 1852a:398—399 (Litorina parvula Philippi, 1849, is a nomen dubium, see synon- ymy of N. apicina). C. B. Adams, 1852b:174—175. Littorina dubiosa C. B. Adams, 1852a:398-399, 537 (Ta- boga [Taboga Island], Panama; lectotype (Turner, 1956: 118, pl. 13, fig. 13) MCZ 186573, seen, Figure 11Z herein; approx. 300 paralectotypes MCZ 139045, seen; 17 paralectotypes BMNH 1865.11.22.33, seen). C. B. Adams, 1852b:174—-175, 313. Littorina ? parvula var. dubiosa—Carpenter, 1857a:273. Littorina aspera dubiosa—Turner, 1956:45—46, pl. 13, fig. 13. Littorina dubiosa dubiosa—Keen, 1958:282, fig. 175. Littorina philippii—Carpenter, 1863:352—353 (in part, in- cludes N. apicina; not Carpenter, 1857 = N. apicina). Taxonomic history: This species exhibits a range of shell sculpture from smooth to strongly ribbed. The ribbed shells have in the past been invariably identified as aspera, a name now restricted to a similar but largely allopatric species occurring mainly in Mexico (see also Taxonomic History of N. aspera). The fact that the spe- cies was named at all is owing to the rather common occurrence in Central America of a dwarf, smooth form that is superficially very different from larger ribbed shells. These smooth shells have frequently been con- fused with N. apicina (see Taxonomic History of that Page 131 species). In fact, C. B. Adams (1852a) introduced his new species under the heading “‘Littorina parvula?’ (here considered a nomen dubium, possibly a synonym of N. apicina) and prefaced the description with the qualifica- tion “If our shell is distinct from Philippi’s species, it may take the name of L. dubiosa....” (This conditional pro- posal does not prevent availability of the name; ICZN, 1999, Art. 11.5.1.) The shells on which he based his new taxon do indeed bear a superficial resemblance to N. ap- icina, but that species is rare in Panama and is not rep- resented among the syntypes of L. dubiosa, or in the large collection of littorinids from Panama in the C. B. Adams Collection in the BMNH. Adams himself identified larger shells of N. dubiosa from Panama as Littorina aspera. Since its description, the name dubiosa has been used as valid only twice (Turner, 1956; Keen, 1958). Diagnosis: Shell large or small, spire whorls slightly rounded, spire profile often slightly concave; 6—8 primary spiral grooves; 7-11 grooves above periphery of last whorl; sculpture of deep grooves up to 2 times rib width on last whorl of large shells, but grooves narrow or faint on small shells; fawn with oblique brown axial stripes and (on spire whorls only) a broad spiral zone of blue- grey just above periphery. Penis with stout, gradually ta- pering filament; large mamilliform gland (larger than small glandular disc) almost filling short projection of base. Material examined: 55 lots (including 21 penes, 5 sperm samples, 5 pallial oviducts, | spawn sample, 4 radulae). Shell (Figures 11P—Z): Mature shell height 3.9—-19.4 mm. Shape high-turbinate (H/B = 1.32-1.77, SH = 1.57- 1.92); spire whorls slightly rounded, suture distinct; spire profile sometimes slightly concave, giving slight onion shape; periphery of last whorl weakly angled. Columella concave, hollowed, and slightly pinched at base; small eroded parietal area. Sculpture of (5) 6-8 primary spiral grooves on spire whorls; ribs subequal, or slightly wider at suture and periphery; 7-11 grooves above periphery of last whorl, secondary sculpture usually absent, but rarely single narrow secondary riblets appear in grooves, in- Figure 14. Penes of Nodilittorina aspera group (continued): N. apicina (A-G), N. penicillata (H—-K), and N. _ paytensis (L—-P). A. Bahia Santa Maria, Cabo San Lucas, Baja California Sur, Mexico (BMNH 20001232; shell H = 7.2 mm). B. Mazatlan, Sinaloa, Mexico (BMNH 20001241; shell H = 9.9 mm). C, D. Playa de los Muertos, Puerto Vallarta, Jalisco, Mexico (BMNH 20001242; shell H = 3.8 mm, 5.6 mm). E. Puerto Marques, Acapulco, Guerrero, Mexico (BMNH 20001237; shell H = 7.8 mm). EK Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001243; shell H = 6.0 mm). G. Same, Esmeraldas, Ecuador (BMNH 20001236; shell H = 11.8 mm). H, K. Punta San Felipe, Baja California Norte, Mexico (BMNH 20001250; shell H = 8.2 mm, 7.7 mm). I. Topo- lobampo, Sinaloa, Mexico (BMNH 20001247; shell H = 10.6 mm). J. Cabo San Lucas, Baja California Sur, Mexico (BMNH 20001244; shell H = 7.6 mm). L. Ballenita, Guayas, Ecuador (BMNH 20001257; shell H = 9.5 mm). M. Anconcito, Guayas, Ecuador (BMNH 20001254; shell H = 5.3 mm). N. Atacames, Esmeraldas, Ecuador (BMNH 20001253; shell H = 10.0 mm). O. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001252; shell H = 8.0 mm). P. Same, Esmeraldas, Ecuador (BMNH 20001260; shell H = 10.9 mm). Abbreviation: gf, glandular flange. Shading conventions as in Figures 3, 13. Scale bar = 1 mm. D. G. Reid, 2002 Page 133 creasing number of grooves above periphery to 13-15; development of sculpture is variable; on last whorl of large shells grooves enlarge to 1—2 times width of inter- vening ribs, which become raised, rounded cords; some- times only grooves just above and below periphery be- come enlarged, others remaining as incised lines; in dwarf forms all grooves may be faint, or grooves become obsolete, remaining only near periphery and suture; spiral microstriae absent. Protoconch not seen. Ground color cream to fawn, with narrow oblique brown stripes; typi- cally, on lower half of spire whorls a broad blue-grey background zone (not a discrete dark band) which be- comes indistinct on last whorl where (in corresponding region) brown pattern may appear as a fine tessellation; in dwarf and smooth shells ground color is white to cream, with broad blue-grey band just above periphery and a blue-grey line below periphery, usually with oblique or waved axial stripes superimposed (although these may be faint or absent); aperture brown, external pattern showing through, with 2 pale spiral bands at base and shoulder; columella brown. Animal: Head black, only rarely an unpigmented stripe across snout, tentacle pale at base and around eye, with two longitudinal black stripes and black spot at tip; sides of foot speckled black. Opercular ratio 0.37—0.41. Penis (Figures 13M-—Q): filament moderately long, gradually ta- pering, smooth, thickened, and glandular, 0.6—0.8 total length; sperm groove open to tip; mamilliform gland larg- er than glandular disc, often swollen and almost filling the short projection of base; penis unpigmented or only slightly pigmented at base. Euspermatozoa 64 ym; para- spermatozoa (Figure 15N) with single (rarely double) broad rectangular or trapezoidal rod-pieces, 11-16, wm filling cell, with few large round granules. Pallial oviduct (Figure 15C) with large copulatory bursa opening at half length of straight section and extending back to albumen gland. Spawn (Figure 151) a simple biconvex capsule 140 jum diameter, with upper ring and slight lower flange, containing single ovum 40 pm diameter. Radula (Figure 9D): Relative radular length 5.6—7.8. Rachidian: length/width 1.36—1.90; major cusp elongate, rounded at tip. Lateral and inner marginal: major cusps elongate, rounded at tip. Outer marginal: 7—9 cusps. Habitat: Abundant on moderately exposed to sheltered shores; found even in somewhat turbid embayments and close to stream outflows; therefore shows a continental distribution pattern on the mainland. However, the species also occurs on Isla del Coco and there is a single record from the Galapagos. Occurs on rocks (including volcanic conglomerate, tuff, sandstone) in littoral fringe and at top of eulittoral zone. Dwarf specimens found in pools at top of shore. Rare on exposed coasts, where small specimens nestle among barnacles and in crevices. Microsympatric with N. apicina on moderately exposed shores, but ex- tends to higher levels. On sheltered shores (particularly in Gulf of Panama) N. dubiosa is often the only member of the N. aspera group to be found. Ecological studies of “Littorina aspera” in Panama by Markel (1971), Garrity & Levings (1981), and Garrity (1984) were based largely on this species, but may have included others in the N. aspera complex. Range (Figure 17): El Salvador (and perhaps Guatemala) to Colombia, Isla del Coco, Galapagos Islands. Range limits: Guatemala (LACM 149773, 1 specimen); Punta Amapala, El Salvador (USNM 780445, 10 specimens); San Juan del Sur, Nicaragua (USNM 23304); Punta San Francisco, Bahia Solano, Colombia (USNM 819739); Ladrilleros, Colombia (USNM 807724); Isla Gorgona and Isla Gorgonilla, Colombia (USNM 819729, 3 specimens); Isla del Coco, Costa Rica (KLK; 2 collections, 15 spec- imens); Punta Pitt, Isla San Cristobal, Galapagos (BMNH 20001227, 4 specimens). The species is rare in the Ga- lapagos Islands, with only a single verified collection; re- cords in faunal lists from the islands (Schwengel, 1938; Finet, 1985, 1994; Kaiser, 1993, 1997) are based on likely misidentification and on literature records; the two lots in LACM quoted by Finet (1994) are N. conspersa and an incorrectly localized sample of a mixture of N. aspera and N. penicillata. The unlocalized record from Guate- mala is at least 150 years old and requires verification, Figure 15. Pallial oviducts (A-F), egg capsules (G—I), and paraspermatozoa (J—R) of Nodilittorina aspera group: _ N. aspera (A, J, K), N. tenuistriata Reid, sp. nov. (B, L, M), N. dubiosa (C, I, N), N. apicina (D, O, P), N. penicillata (E, Q), N. paytensis (F—H, R). A, J. Mazatlan, Sinaloa, Mexico (BMNH 20001219; shell H = 11.0 mm). B. Same, Esmeraldas, Ecuador (BMNH 20001226; shell H = 14.2 mm). C. Punta Amapala, El Salvador (USNM 332140; shell H = 10.2 mm). D. Puerto Marques, Acapulco, Guerrero, Mexico (BMNH 20001237; shell H = 11.5 mm). E, Q. Punta San Felipe, Baja California Norte, Mexico (BMNH 20001250; shell H = 10.5 mm). FE Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001259; shell H = 10.8 mm). G, H. Ballenita, Guayas, Ecuador (BMNH 20001257). I, N. Punta Morales, Golfo de Nicoya, Costa Rica (BMNH 20001229). K. Puerto Marques, Acapulco, Guerrero, Mexico (BMNH 20001217). L. Atacames, Esmeraldas, Ecuador (BMNH 20001221). M. Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 2000314). O. Playa de los Muertos, Puerto Vallarta, Jalisco, Mexico (BMNH 20001242). P. Same, Esmeraldas, Ecuador (BMNH 20001236). R. Same, Esmeraldas, Ecuador (BMNH 20001260). Shading conventions as in Figure 4. Scale bars: A-F = | mm; G-I = 0.1 mm; J-R = 20 pm. Page 134 The Veliger, Vol. 45, No. 2 D. G. Reid, 2002 but would be of interest since it lies in the Central Amer- ican Gap (see Discussion). Remarks: This species displays a confusing variation in shell size, coloration, and sculpture. As a result, the small, smooth, or weakly sculptured examples have in the past been classified with N. apicina, whereas the large, striped, strongly ribbed shells have been included with N. aspera. As in some other eastern Pacific Nodilittorina species, this shell variation is correlated with microhabitat, the dwarf forms (Figures 11R, S, Z) occurring in high-level saline pools and on exposed coasts, and the larger shells on more sheltered shores where conditions for growth are presumably more favorable. Unlike N. aspera and N. ten- uistriata, the dwarf forms are not darkly patterned. On moderately exposed shores (for example in Costa Rica) N. dubiosa is frequently sympatric with N. apicina, and discrimination between them is sometimes difficult. In the latter, the sculpture is of incised lines only (never wide grooves), the color paler (white ground color, often with a zigzag or finely tessellated pattern), the columella long and straight, and the overall shape more oblique. In contrast, when present, the grooves on the shell of N. dubiosa become wide at least near the periphery of the last whorl (or over the whole whorl), the ground color is cream to fawn (usually with a regular lined pattern), and the columella slightly curved. Identification of males can be confirmed by the penis, which in N. apicina has a long, wrinkled filament and protruberent glandular disc, and in N. dubiosa a smooth, tapering filament and much larger mamilliform gland. The form of the paraspermatozoa also differs. Larger examples of N. dubiosa share with the more northern species, NV. aspera, the unusual feature of wide grooves (up to twice the width of the intervening raised ribs) on the last whorl, besides a tendency to an onion- shaped profile, and for these reasons the species was at first believed to be simply a southern form of N. aspera. However, there is a difference in the penis, the mamilli- form gland of N. dubiosa being much larger, almost fill- ing the basal projection. Unfortunately, only two samples of sperm were available from N. aspera, but in these the long rod-pieces differed from the broader or trapezoidal rod-pieces in five samples from N. dubiosa. Close ex- amination of the shells reveals that their color patterns are distinct, N. aspera showing coarser axial stripes, white ground color, and a strong dark spiral band above Page 135 the periphery of at least the spire whorls, in contrast to the cream or fawn ground color with diffuse peripheral blue-grey band, and finer axial stripes of N. dubiosa. The typical habitats of the two are also suggestive, on exposed coasts in N. aspera, and mainly on moderately sheltered shores in N. dubiosa. For these reasons, the two are here regarded as separate species. Their known distributions overlap slightly, in El Salvador and Nicaragua, but they have not yet been recorded at the same locality in order to confirm that their characters remain distinct. Addition- al, if indirect, evidence for their separate status is that there is a third species, N. tenuistriata, which has been found in sympatry with both N. aspera and N. dubiosa, and is itself the more likely sister-species of N. aspera. Nodilittorina tenuistriata is easily separated from N. du- biosa by its finer sculpture (7-10 primary spiral grooves on spire whorls, 10—15 narrow grooves above periphery of last whorl), broad dark spiral band above the periph- ery, and more rounded whorls; it also occurs on more exposed shores than N. dubiosa. Since the typical habitat on relatively sheltered shores and tolerance of turbidity and freshwater influence sug- gest a continental distribution, the records of N. dubiosa on Isla del Coco and the Galapagos are unexpected. The provenance of these specimens is completely reliable. The specimens from Isla del Coco are dry shells, but these are entirely typical (Figure 11W). The four from the Galapagos are elongate and weakly sculptured, with an unusually prominent dark band above the periphery (Figure 11Q); the two dissected specimens were female so that the important characters of the penis were not available. The shape of the columella shows that these are not N. apicina, and the weak sculpture and brownish coloration suggest that they are not N. tenuistriata. The occurrence of N. dubiosa on Isla del Coco and the Ga- lapagos Islands could be related to strong currents that originate in the Gulf of Panama from February to April and flow toward the southwest (Finet, 1991). Nodilittorina apicina (Menke, 1851) (Figures 12A-—I, 14A—G, 15D, O, P, 16A—D, 17) ? Litorina parvula Philippi, 1849:149 (Panama; types lost; nomen dubium). Litorina [aspera var.] apicina Menke, 1851:164 (Mazatlan [Mexico]; lectotype (here designated, 7.1 < 4.8 mm) Figure 16. Radulae of Nodilittorina apicina (A—D), N. paytensis (E), N. peruviana (F), and N. araucana (G, H). A, B. Playa de los Muertos, Puerto Vallarta, Jalisco, Mexico (BMNH 20001242; flat, shell H = 8.7 mm; at 45°; shell H = 5.0 mm). C, D. Playa de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001243; two views of radula, flat and at 45°; shell H = 7.1 mm). E. Punta Chocolatera, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001259; at 45°; shell H = 9.1 mm). E Playa la Lisera, Arica, Tarapaca, Chile (BMNH 20001271; at 45°; shell H = 12.1 mm). G, H. Las Cruces, Valparaiso, Chile (BMNH 20001263; two views of radula, flat and at 45°; shell Il H = 7.8 mm). Scale bars = 50 wm. Page 136 The Veliger, Vol. 45, No. 2 120° 110° 100° 90° ° ° sas 80 : 70 3 0° 3 O° 20° 20° 1 0° 1 0° * N. aspera oO N. tenuistriata A Alamo & Valdivieso (1987, 1997) A N. dubiosa @ N. apicina 4 N. penicillata * N. paytensis B Alamo & Valdivieso (1987, 1997) C Vegas (1968) O 2 0° 10° 10° 120° 110° 100° 90° 80° 70° Figure 17. Geographical distribution of species of the Nodilittorina aspera group (records based on material examined and quoted literature sources). There are in addition an unlocalized record of N. aspera from El Salvador (von Martens, 1900) and another of N. dubiosa trom Guatemala (LACM 149773). DaGaReidy 2002 SMF 314713a, Figure 12F; 3 paralectotypes SMF 314713/3; types seen). Litorina (Melaraphe) philippii Carpenter, 1857b:349—350 (Mazatlan [Mexico]; lectotype (here designated, 10.9 x 7.3 mm) BMNH 1857.6.4.1682/1, Figure 12B; 109 par- alectotypes BMNH 1857.6.4.1671—1685 (100 shells and 9 separate opercula; one shell figured by Keen, 1968, pl. 57, fig. 54; one shell is N. aspera); types seen). Litorina philippii—Carpenter, 1857a:257, 326, 364. Carpen- ter, 1864b:546, 550, 623 (in part, includes N. penicil- lata, N. dubiosa). Weinkauff, 1882:104 (in part, in- cludes N. penicillata). Littorina (Melaraphe) aspera var. philippii—Tryon, 1887: 249, pl. 44, fig. 84. Littorina (Melarhaphe) philippii—von Martens, 1900:577, 584, pl. 43, fig. 12 (in part, includes N. dubiosa, N. penicillata, N. modesta). Littorina philippii—Carpenter, 1863:352—353 (in part, in- cludes N. dubiosa). Pilsbry & Lowe, 1932:124. Littorina dubiosa philippiti—Keen, 1958:282, 623, fig. 175b. Keen, 1968:410, pl. 57, fig. 54. Litorina aspera—Weinkauff, 1883:220 (in part, includes N. aspera, N. dubiosa, N. penicillata). Littorina aspera—Keen, 1971:365, fig. 181 (part) (in part, includes N. aspera, N. penicillata, N. dubiosa, N. mo- desta, N. interrupta). Littorina (Austrolittorina) aspera—Abbott, 1974:69 (in part, includes N. aspera, N. dubiosa, N. penicillata). Littorina (Melarhaphe) philippii var. subsuturalis von Mar- tens, 1900:577, 585, pl. 43, fig. 17 (San José, W. Gua- temala; five syntypes MNB, seen). Taxonomic history: Litorina parvula was only briefly described, and not figured, by Philippi (1849), and no types have been traced. The color pattern of undulating black lines, impressed spiral lines (7 on last whorl) and small size (7.6 X 4.9 mm) suggest the present species, but do not exclude others that are similar. The material was collected by the author’s brother, E. B. Philippi, from “Panama,” but he visited both the eastern Pacific Ocean and Caribbean Sea, so the description might even apply to one of the several black and white Nodilittorina species of the Caribbean. This is regarded as a nomen dubium. The type material of Litorina apicina, recently rediscov- ered in the Bronn collection in SME confirms the precise description given by Menke (1851). The name was pro- posed preliminarily, within his account of Litorina as- pera. (Translation from the German: ‘‘Without separating this form presently as a distinct species, I call it prelim- inarily L. apicina.”’ This is here interpreted as introduc- tion of an infraspecific name and not as publication in synonymy, which would invalidate the name for it has not been used since; ICZN, 1999, Art. 11.6.) Menke (1851) applied the name to small shells (7.6 X 4.8 mm) that he separated from the young of Litorina aspera by the more tumid shape, lack of dark spiral band, and even- ly spaced ribs separated by narrow grooves; these char- acters are precisely those that separate this species from N. aspera, which is the only other black and white litto- rinid common at Mazatlan. In the Reigen Collection, Car- Page 137 penter (1857b) had a large amount of material also from Mazatlan and he recognized that this species was distinct from N. aspera at the same locality. Nevertheless, he re- jected Menke’s name, arguing that it applied to young aspera and was in any case inappropriate for a species which was almost always eroded; on these dubious grounds he introduced Litorina philippii. Carpenter’s (1857b) species is represented by 101 shells from the Rei- gen Collection in BMNH, of which only one is N. aspera, and a lectotype is here selected. The choice of apicina rather than philippii as the valid name for this species is in accordance with the principle of priority; although the younger name has been used more frequently in the lit- erature, it has not been used sufficiently often for prece- dence to be reversed (ICZN, 1999, Art. 23.9) and not at all since 1968. Three of the five syntypes of L. philippii var. subsuturalis have an unusually dark peripheral band, but the form of the columella and of the spiral sculpture confirms that all belong to N. apicina (and not to N. du- biosa). A number of authors (Carpenter, 1857a, b, 1863, 1864b; Weinkauff, 1882; von Martens, 1900; Pilsbry & Lowe, 1932; Keen, 1958) have discriminated a smaller, smooth-shelled species from the larger, more strongly sculptured shells named aspera. The names parvula, ap- icina, philippii, and dubiosa have been applied to this smaller species, but the grouping is often not a natural one since most species in the N. aspera group can de- velop a relatively smooth shell. In some geographical ar- eas, a distinction based on sculpture alone does indeed correctly separate sympatric species. Thus, at Mazatlan, the large, ribbed shells are N. aspera s.s., while small, smoother ones are N. apicina (the only other member of the N. aspera group to occur there, N. penicillata, is rare), as correctly recognized by both Menke (1851) and Car- penter (1857a, b; as philippii). Elsewhere, the smooth- shelled forms include N. penicillata and weakly sculp- tured examples of N. dubiosa, which have therefore often been included with the present species (Carpenter, 1863, 1864b; Weinkauff, 1882; von Martens, 1900; Keen, 1958). Weinkauff (1883) first synonymized these smooth species with aspera, as also done by Keen (1971) and Abbott (1974), and N. apicina has not since been recog- nized as distinct. Diagnosis: Shell of moderate size, spire whorls moder- ately rounded, spire profile distinctly convex; columella long, straight; 5—7 primary spiral grooves; 9-12 grooves above periphery of last whorl; sculpture of incised lines or narrow grooves; white with grey-brown to black oblique or zigzag axial lines; no dark spiral bands, but often an indistinct greyish zone from periphery to shoul- der, where pattern tends to form tessellation rather than axial lines. Penis with long, wrinkled filament; mamilli- form gland and protruberant glandular disc on projection of base. Page 138 Material examined: 56 lots (including 32 penes, 9 sperm samples, 4 pallial oviducts, 6 radulae). Shell (Figures 12A-I): Mature shell height 2.9—14.9 mm. Shape obliquely high-turbinate to moderately tall (H/B = 1.33-1.71, SH = 1.31—1.94); spire whorls mod- erately rounded, suture distinct; spire profile usually con- vex, giving oblique shape; periphery of last whorl weakly angled. Columella long, straight, slightly hollowed, and pinched at base; small eroded parietal area. Sculpture of 5-7 primary spiral grooves on spire whorls; these remain as incised lines, or become wider toward periphery of last whorl (occasionally up to half width of peripheral rib), only rarely become obsolete; grooves number 9—12 above periphery of last whorl, or occasionally up to 15 if some secondary grooves appear; ribs may be subequal, but usu- ally 3—4 posterior ribs are slightly wider, and peripheral rib is slightly larger and raised; spiral microstriae absent. Protoconch not seen. Color white, with variable dark pat- tern; commonly brown oblique or zigzag axial lines, often forming grey-brown tessellation in greyish zone from pe- riphery halfway to suture; sometimes strong black oblique axial stripes, occasionally anastomosing in pe- ripheral zone to give irregular black band (dwarf shells from exposed localities only); sometimes a fine pallid beige or brown tessellation throughout, darkening to grey in zone from peripery halfway to suture; this indistinct greyish zone with darker pattern is typical, but distinct dark spiral lines or bands are almost always absent (rare- ly, an anterior spiral band is present on upper spire whorls only); aperture brown, with pattern showing through and 2 pale spiral bands, at base and shoulder; columella brown. Animal: Head black, sometimes a thin unpigmented stripe across snout, tentacle pale at base and around eye, with two longitudinal black lines, sometimes fusing dis- tally or with black spot at tip; sides of foot grey to black. Opercular ratio 0.31—0.41. Penis (Figures 14A—G): fila- ment long, gradually tapering, rounded at tip, lower half of filament with annular wrinkles and not clearly differ- entiated from wrinkled penial base, filament about 0.5— 0.7 total length; sperm groove open to tip; mamilliform gland and large glandular disc on projection of base, disc protrudes as a lobe; penis unpigmented or only slightly pigmented at base. Euspermatozoa 54—68 j.m; parasper- matozoa (Figures 150, P) of single, long, stout, parallel- sided rod-pieces, 21—32 jzm, often with rounded or point- ed terminal caps, attached cytoplasm usually thin, with small indistinct granules, often one large granule (perhaps the nucleus) visible. Pallial oviduct (Figure 15D) with large copulatory bursa opening at three-quarters of the length of straight section and extending back to albumen gland. Spawn not observed. Radula (Figures 16A—D): Relative radular length 2.8— 4.8. Rachidian: length/width 1.42—2.0; major cusp elon- The Veliger, Vol. 45, No. 2 gate, rounded, or pointed at tip. Lateral and inner mar- ginal: major cusps elongate; rounded, blunt or pointed at tip. Outer marginal: 6—8 cusps. Habitat: Clustered in crevices and at margins of pools, in upper eulittoral and lower littoral fringe; sometimes among barnacles and mussels in mid-eulittoral zone; ex- posed and moderately sheltered coasts; recorded on gran- ite, basalt, sandstone, mudstone, and concrete; usually common to abundant. Although for most of its range this species is found only in relatively exposed, oceanic sit- uations, there are no records from offshore islands and it is sometimes found in embayments and lagoons (e.g., La- guna Ojo de Liebre and Ventosa Bay, Mexico; Golfo de Nicoya, Costa Rica). Overlapping with, but zoned slightly below N. dubiosa and N. aspera in Central America and Mexico, respectively; in Ecuador microsympatric with WN. paytensis, but below N. tenuistriata. Range (Figure 17): Western Baja California to northern Ecuador. Range limits: Laguna Ojo de Liebre, Baja Cal- ifornia Sur (USNM 130598, 2 specimens); Punta Abreo- jos, Baja California Sur (USNM 862105); Bahia Mag- dalena, Baja California Sur (USNM 264566); Cabo San Lucas, Baja California Sur (BMNH 20001231); Bahia Santa Marfa, E of Cabo San Lucas, Baja California Sur (BMNH = 20001232); Mazatlan, Sinaloa (BMNH 20001233); Bahia Ventosa, Golfo de Tehuantepec, Oa- xaca (USNM 60449); Salina Cruz, Oaxaca (LACM 149771); La Libertad, El Salvador (LACM 149774, 30 specimens); Punta Amapala, El Salvador (USNM 780445); Coyolita, Golfo de Fonseca, Honduras (USNM 749642); Corinto, Nicaragua (CAS 122359); Fort Ama- dor, Panama (USNM 732997, 11 specimens; BMNH 20001234, 1 specimen); Atacames, Esmeraldas, Ecuador (BMNH 20001235); Punta Galera, Esmeraldas, Ecuador (USNM 711369). The species is common throughout most of its range, but is rare in the Gulf of Panama (only two records), perhaps connected with eutrophic and large- ly sheltered conditions there. Remarks: Shape and sculpture are relatively constant in this species, but it displays some geographical variation in color pattern. In specimens from Mexico, the pattern is usually of dark axial stripes on a white ground, whereas in Central America and Ecuador the coloration is greyish or pallid, with a finer and more diffuse tessellation. In the former group, the most pronounced black and white striped pattern is often found in dwarf shells (Figure 12G) from shallow pools in the upper eulittoral zone; abrupt transitions to a paler and more tessellated pattern can sometimes be seen, suggesting phenotypic plasticity in the expression of coloration. At two localities (Puerto Vallarta, Jalisco; Puerto Quepos, Costa Rica), a commen- sal flatworm occurs occasionally in the mantle cavity (see Remarks on N. modesta group). This species has the widest geographical range of all D. G. Reid, 2002 Page 139 the eastern Pacific Nodilittorina species and is the only one found both in central Mexico and south of Costa Rica. Over its range it is sympatric with several other species, and confusion is most likely with N. aspera and N. penicillata in Mexico, and with N. dubiosa, N. pay- tensis, and N. tenuistriata in Central and South America. Its most characteristic features are the relatively long and straight columella, the somewhat oblique shape (slightly Succinea-like), the relatively narrow grooves (not more than half width of ribs, distinguishing it from the more strongly sculptured examples of N. aspera and N. dubio- sa), and the lack of a strong dark spiral band or line above the periphery (as present in N. penicillata, N. aspera, N. tenuistriata and usually in N. paytensis). Similarities of shell, paraspermatozoa, and geographical proximity sug- gest that its closest relative may be N. penicillata. Nodilittorina penicillata (Carpenter, 1864) (Figures 9H, 12J—Q, 14H—K, 15E, Q, 17) Littorina (philippii, var.) penicillata Carpenter, 1864a:477 (Cape St Lucas [Cabo San Lucas, Baja California], Mexico; lectotype (here designated, 8.6 < 5.3 mm) USNM 4058, seen, Palmer, 1963:pl. 61, fig. 7, Figure 12L herein: 2 paralectotypes USNM 678691; 31 para- lectotypes USNM 862110 (3 of these are N. aspera); 20 paralectotypes MCZ 086976; 1 paralectotype ANSP 212152; 26 paralectotypes BMNH 1865.11.6.70; 19 paralectotypes BMNH 19991559; all paralectotypes seen). Litorina philippii var. penicillata—Weinkauff, 1882:104. Littorina (Melaraphe) aspera var. penicillata—Tryon, 1887: 250, pl. 44, fig. 85. Littorina (Melarhaphe) philippii var. penicillata—von Mar- tens, 1900:577, 584-585, pl. 43, fig. 14. Littorina penicillata—Pilsbry & Lowe, 1932:124. Littorina dubiosa penicillata—Keen, 1958:282, fig. 175a. Palmer, 1963:334—335, pl. 61, fig. 7. Littorina (Austrolittorina) penicillata—Rosewater, 1970: 423. Nodilittorina (Nodilittorina) penicillata—Reid, 1989a:99 (doubtfully included in synonymy of N. aspera). Litorina aspera—Weinkauff, 1883:220 (in part, includes N. aspera, N. dubiosa, N. apicina). Littorina aspera—Keen, 1971:365, fig. 181 (part) (in part, includes N. apicina, N. aspera, N. dubiosa, N. modesta, N. interrupta). Littorina (Austrolittorina) aspera—Abbott, 1974:69 (in part, includes N. aspera, N. dubiosa, N. apicina). Taxonomic history: This species was first described by Carpenter (1864a) as a variety of L. philippii (= N. api- cina), characterized by its distinctive color pattern. It is represented by a large type series, of which the specimen figured by Palmer (1963) is here selected as the lectotype. Of the 79 known paralectotypes three are N. aspera, per- haps included inadvertently. Subsequent authors initially accepted this status as a color variety of a supposed smooth-shelled species named philippii or dubiosa (Wein- kauff, 1882; von Martens, 1900; Keen, 1958; Palmer, 1963). Others synonymized it with aspera, which was believed to be a single widely variable species (Wein- kauff, 1883; Tryon, 1887; Keen, 1971; Abbott, 1974). However, several authors have listed it as a distinct spe- cies; though the evidence has not been discussed, they were presumably impressed by the restriction of the dis- tinctive color form to the Gulf of California and its sym- patric occurrence with typical N. aspera (Pilsbry & Lowe, 1932; Rosewater, 1970; doubtful status in Reid, 1989a). Diagnosis: Shell of moderate size, spire whorls moder- ately rounded; 6—9 primary spiral grooves; 8—11 grooves above periphery of last whorl; sculpture of incised lines only; white with oblique or waved grey to brown axial lines, one spiral dark line above periphery and one below. Penis with broad, pointed filament, thickened at base; ma- milliform gland and large glandular disc on projection of base. Material examined: 57 lots (including 15 penes, 2 sperm samples, 4 pallial oviducts, 4 radulae). Shell (Figures 12J—Q): Mature shell height 3.9—15.3 mm. Shape moderately tall (H/B = 1.48—-1.84, SH = 1.60—2.05); spire whorls moderately rounded, suture dis- tinct; spire profile straight to slightly convex; periphery of last whorl weakly angled. Columella concave, hol- lowed and pinched at base; no eroded parietal area. Sculpture of 6—9 primary spiral grooves on spire whorls; these remain as incised lines, numbering 8—11 above pe- riphery of last whorl, or occasionally become faint or obsolete on shoulder; rarely (only on largest shells) a sec- ondary groove divides each primary rib; ribs subequal, except peripheral rib which is twice as wide; spiral mi- crostriae absent. Protoconch not seen. Color bluish white, with brown, grey, or black pattern of fine wavy or oblique axial lines; two narrow spiral lines of blue-grey or black, one on third rib above peripheral rib, one in groove im- mediately below peripheral rib, occasionally other dark lines appear in grooves between these prominent lines, or sometimes spiral lines may become obsolete on last whorl (spiral line above periphery remains visible on spire); ap- erture dark chestnut brown with 2 pale spiral bands, at base and shoulder, where external pattern shows through; columella blackish brown. Animal: Head dark grey to black, sometimes a thin un- pigmented stripe across snout, tentacle pale at base and around eye, with two longitudinal black lines and black spot at tip; sides of foot grey to black. Opercular ratio 0.41—0.51. Penis (Figures 14H—K): filament broad, point- ed at tip, with thickened flange at base on medial side, smooth and clearly differentiated from wrinkled penial base, about 0.6—0.8 total length; sperm groove open to tip; mamilliform gland and large glandular disc on stout projection of base; penis unpigmented. Euspermatozoa 57-64 wm; paraspermatozoa (Figure 15Q) of single, long, stout, parallel-sided rod-pieces, 24—35 jm, with cluster Page 140 The Veliger, Vol. 45, No. 2 of large spherical granules attached. Pallial oviduct (Fig- ure 15E) with large copulatory bursa opening halfway along straight section and extending back to albumen gland. Spawn not observed. Radula (Figure 9H): Relative radular length 3.9-8.5. Rachidian: length/width 1.38—1.67; major cusp elongate, pointed to rounded at tip. Lateral and inner marginal: ma- jor cusps elongate, rounded at tip. Outer marginal: 8—9 cusps. Habitat: Clustered in crevices and at margins of saline pools, in littoral fringe; sheltered and moderately exposed coasts; recorded on granite, conglomerate, basalt, and muddy rocks; usually common to abundant. Sympatric with N. aspera and N. apicina in southernmost Baja Cal- ifornia, but extends to higher levels on the shore. Range (Figure 17): Gulf of California, southern Baja California, to Mazatlan, Islas Tres Marias, Puerto Vallar- ta, and Islas Revillagigedo. Range limits: Bahia Magda- lena, Baja California Sur (USNM 819877, 3 specimens); Cabo San Lucas, Baja California Sur (BMNH 2001244); Bahia Coyote, Bahia Concepcién, Baja California Sur (USNM 558627, | specimen); San Felipe, Baja California Norte (BMNH 20001245); Puerto Penasco, Sonora (USNM 701417); Puerto Libertad, Sonora (USNM 809245, 1 specimen); S end Isla del Tiburén, Sonora (USNM 264910, 6 specimens); San Carlos, 20 km W of Guaymas, Sonora (BMNH 20001246); Topolobampo, Sinaloa (BMNH 20001247); Mazatlan, Sinaloa (BMNH 1857.6.4.1670, 3 specimens; BMNH 20001248, 2 speci- mens); Isla Maria Cleofas, Islas Tres Marias (KLK, 1 specimen); Playa de los Muertos, Puerto Vallarta, Jalisco (BMNH 20001249, 1 specimen); Isla Socorro, Islas Re- villagigedo (KLK, 2 specimens). This species has a cu- rious distribution, being abundant in most parts of the Gulf of California (from Cabo San Lucas northward, in- cluding San Felipe, Guaymas, and Topolobampo), with the apparent exception of the area between Bahia Con- cepcion and San Felipe (this gap is probably real, since the smaller species N. albicarinata is well represented by collections from this part of the Gulf). Only nine speci- mens have been seen from localities south of the Gulf of California, where it is a rare immigrant (von Martens, 1900, noted its rarity at Mazatlan). Remarks: The shell characters are relatively constant in this species, which is most easily recognized by the pat- tern of fine “‘pencilled’’ axial and two spiral lines. In other species with dark spirals, a wider band is present, occupying the lower half of each spire whorl and a zone just above the periphery on the last whorl. This species most resembles N. apicina, and the two can be found commonly together in the vicinity of Cabo San Lucas (southernmost Baja California) and occasionally on the Mexican mainland. They can always be distinguished by color pattern, which in N. apicina from these areas is of strong axial stripes with no spiral lines. These two are likely sister species, as suggested by similarity of shell sculpture, paraspermatozoa, and parapatric geographical distribution. Nodilittorina paytensis (Philippi, 1847) (Figures 12R—BB, 14L-—P, 15F—H, R, 16E, 17) Litorina paytensis Philippi, 1847:2:166, Litorina pl. 3, fig. 25 (Payta in Peruvia [Paita, Piura, Peru]; types pre- sumed lost; lectotype (here designated) Philippi, 1847: Litorina pl. 3, fig. 25, central shell, Figure 12BB here- in). Weinkauff, 1882:68, pl. 9, figs. 1, 4. Weinkauff, 1883:218. Littorina (Melaraphe) paytensis—H. & A. Adams, 1854: 314. Tryon, 1887:250, pl. 45, figs. 90, 91 (in part, in- cludes N. araucana). Littorina paytensis—Vegas, 1968:8. Keen, 1971:366, fig. 184 (possible subspecies of L. modesta). Petia, 1971b: 47, pl. 1, fig. 5. Finet, 1985:13 (possible subspecies of L. modesta). Finet, 1994:18, 127 (possible synonym of N. araucana). Littorina (Littorinopsis) paytensis—Rosewater, 1970:423. Alamo & Valdivieso, 1987:25, fig. 37. Alamo & Val- divieso, 1997:17, fig. 37. Paredes et al., 1999:22. Littorina modesta paytensis—Vermetj, 1973:324. Nodilittorina paytensis—Bandel & Kadolsky, 1982:3. Nodilittorina (Nodilittorina) paytensis—Reid, 1989a:99 (doubtfully included in synonymy of N. araucana). Littorina araucana—Dall, 1909:231, 285 (in part, includes N. araucana). Hertlein & Strong, 1955b:273-—274 (in part, includes N. araucana). Taxonomic history: Since it is found mainly in Colom- bia, Ecuador and northern Peru, where the malacological fauna has been poorly studied, this species has seldom appeared in the literature. With limited availability of specimens, some authors of revisions and lists have main- tained it as a distinct species (Weinkauff, 1882, 1883; Rosewater, 1970; Keen, 1971) and in the Peruvian liter- ature it has been correctly identified (Vegas, 1968; Pena, 1971b; Alamo & Valdivieso, 1987, 1997; Paredes et al., 1999). Surprisingly, since its shells are similar to others in the confusing N. aspera group, it has never been syn- onymized with other members. Instead, it has been sug- gested as a possible southern subspecies of the N. mo- desta group (Keen, 1971; Vermeij, 1973; Finet, 1985), probably on account of the spotted shell pattern. Others have synonymized it with N. araucana from Peru and Chile (Tryon, 1887; Dall, 1909; Hertlein & Strong, 1955b; doubtfully by Reid, 1989a, and Finet, 1994). Diagnosis: Shell moderately large, whorls slightly round- ed, spire profile straight; 7-11 primary spiral grooves; sculpture of numerous fine grooves (11—23 above periph- ery of last whorl), but often obsolete on last whorl; white to cream, with pattern of smudged brown dots and broad spiral grey to black-brown band just above periphery (paler on last whorl). Penis with wrinkled filament taper- DaGa Red 2002 Page 141 ing to point; large mamilliform gland and small glandular disc borne on projection of base. Material examined: 51 lots (including 18 penes, 6 sperm samples, 4 pallial oviducts, 1 spawn sample, 5 radulae). Shell (Figures 12R—AA): Mature shell height 3.2—15.9 mm (to 19.7 mm, Pena, 1971b). Shape high-turbinate to elongate (H/B = 1.35-1.87, SH = 1.52—2.11); spire whorls slightly rounded, suture distinct; spire profile straight: pe- riphery angled, becoming rounded on last whorl. Colu- mella almost straight, slightly hollowed and pinched at base; eroded parietal area. Sculpture of 7—11 primary spi- ral grooves on spire whorls; primary ribs subequal, or slightly narrower posteriorly (especially if division begins on penultimate whorl); most or all ribs become divided on last whorl, giving 11—23 grooves above periphery, ir- regularly spaced; grooves remain as incised lines only (rarely enlarging to half width of ribs near periphery) and often become obsolete on shoulder or throughout last whorl; peripheral rib twice as wide as others, but not raised; spiral microstriae absent. Protoconch 0.34 mm di- ameter, 2.7 whorls. Color very variable; ground color white to cream; usually with broad black-brown spiral band on lower half of spire whorls, becoming blue-grey and diffuse on last whorl; sometimes brown band contin- ues to last whorl, extending to just above or just below periphery, but no separate spiral band present on base; sometimes spiral band is blue-grey and diffuse throughout teleoconch; most shells have pattern of fine smudged brown dots arranged in oblique axial series (occasionally fused to give fine zigzag lines) across whole surface, usu- ally pale on spire and darkening on last whorl; dots some- times pale or absent; occasionally shells are dark black- brown throughout, with only paler zone at suture and on base, where dots and flames of orange-brown are visible; aperture brown, with 2 pale spiral bands at base and shoulder; columella brown. Animal: Head grey to black, no unpigmented stripe across snout, tentacle pale around eye and usually at in- side of base, with two broad longitudinal black stripes meeting at black tip; sides of foot grey or black speckled. Opercular ratio 0.34—0.39. Penis (Figures 14L—P): fila- ment moderately long, tapering toward pointed tip, with annular wrinkles for most of length, opaque and glandular at base, 0.6—0.8 total length; sperm groove open to tip; glandular disc small, smaller than large mamilliform gland, borne on projection of base; penis unpigmented or only slightly pigmented at base. Euspermatozoa 57-61 jzm; paraspermatozoa (Figure 15R) oval, with single stout rod-pieces with rounded ends, 9—23 im, projecting from cell, cytoplasm packed with large spherical granules. Pal- lial oviduct (Figure 15F) with copulatory bursa opening near posterior end of straight section and extending back to albumen gland. Spawn (Figures 15G, H) an asymmet- rically biconvex pelagic capsule 300 ym diameter, with thin projecting circumferential flange, usually a thickened ring on upper side, containing single ovum 84 pm di- ameter. Protoconch indicates planktotrophic development. Radula (Figure 16E): Relative radular length 2.9—7.2. Rachidian: length/width 1.33—1.75; major cusp elongate, pointed or rounded at tip. Lateral and inner marginal: ma- jor cusps elongate, rounded at tip. Outer marginal: 5—8 cusps. Habitat: Abundant in uppermost eulittoral and lower lit- toral fringe, on exposed and semi-sheltered coasts; rare on sheltered muddy shores; recorded on cliffs and out- crops of sandstone, mudstone, concrete, and volcanic conglomerate. Juveniles appear to settle among barnacles. In Ecuador microsympatric with N. apicina on exposed coasts, but zoned mainly below N. tenuistriata. Recorded also on mangroves and driftwood, on sandy beaches with rocks, in northern Peru (Pena, 1971a, b), but specimens from wood are smaller than from rocks, and this is evi- dently an atypical habitat. Range (Figure 17): Costa Rica, southern Colombia to northern Peru. Range limits: Tarcoles, 20 km SW of San Mateo, Costa Rica (BMNH 20001251, 2 specimens); Pla- ya de Manuel Antonio, Puerto Quepos, Costa Rica (BMNH 20001252, 30 specimens); Isla Gorgona and Isla Gorgonilla, Colombia (USNM 819737, 1 specimen); Ata- cames, Esmeraldas, Ecuador (BMNH 20001253): Ancon- cito, Peninsula Santa Elena, Guayas, Ecuador (BMNH 20001254); Isla Muerta, Golfo de Guayaquil, Ecuador (USNM 819730); Bahia de Sechura, Piura, Peru (BMNH 20001255, 6 specimens). There are in addition three lit- erature records of localities farther south in Peru: Pimen- tel, Lambayeque (Pena, 1970; Alamo & Valdivieso, 1987, 1997), Pacasmayo, La Libertad (Vegas, 1968; Alamo & Valdivieso, 1987, 1997) and Islas Guanape, La Libertad (Alamo & Valdivieso, 1987, 1997); these may be reliable, but should be treated with caution owing to possible con- fusion with N. araucana. These records to the south of the normal limit of the TEP (3—6°S, see Discussion) might be connected with the expansion of the tropical zone during El Nino events (see Paredes et al., 1998). This species is abundant only in Ecuador and far northern Peru. Farther north there are isolated records only from Isla Gorgona and Costa Rica; nevertheless, at Puerto Que- pos it was moderately common, suggesting a possibly self-sustaining population (personal observation). It has not been found in the Gulf of Panama, despite extensive collecting. The species was listed as present in the Ga- lapagos Islands by Finet (1985, 1991), on the basis of two lots in USNM (USNM 819206, 703292, both from Darwin Station, Santa Cruz, total 9 specimens). These are subsamples of a larger lot (17 specimens, G. J. Vermeij Collection), referred to in an ecological paper by Vermeij (1973). All three lots have been examined and the iden- tification confirmed. Nevertheless, this record from the Page 142 The Veliger, Vol. 45, No. 2 Galapagos is considered unreliable (as also concluded by Finet, 1994), since considerable collecting effort at this locality and elsewhere has not found the species in the islands. Vermeij also collected on the mainland of Ec- uador at about the same time, and confusion of labels may have occurred. Remarks: Of the other species in the N. aspera group, N. paytensis most closely resembles N. apicina and N. penicillata in details of shell sculpture and coloration, pe- nial shape, and paraspermatozoa. The variation in shell color in N. paytensis is more extreme than in other members of the N. aspera group. Sometimes both dark brown and grey-white shells can be found together on the shore, and brown juveniles may become pale as adults. Notably, at Punta Carnero on the Peninsula Santa Elena in southern Ecuador all shells were dark brown, or almost black, and of small size (less than 8.5 mm; Figure 12R), whereas from nearby Anconcito, shells of similar size were pale. Furthermore, abrupt color change can occur during the course of growth (Figures 12S, T), so that an ecophenotypic component to the var- iation seems likely. The shells of N. paytensis from Costa Rica are white with a slight grey zone on the spire whorls and only faint grey dots toward the end of the last whorl (Figure 12V), quite distinct from other species found there. Anatomically, the animals from Costa Rica are identical to those from Ecuador. Although so variable in shell color, the species is nev- ertheless most readily recognized by the pattern of small brown dots on the last whorl, combined with a broad brown or blue-grey band on the spire, which is seen in most shells. Dots are also seen in sympatric N. conspersa, but in that species the ground color of the shell is entirely white, and grooves are much wider and fewer in number, so that no confusion should arise. Of the other sympatric species, confusion is likely with N. apicina, although this is less common in Ecuador, which is separated by its pat- tern of oblique axial stripes, breaking up into fine tessel- lation over the mid-part of the last whorl, and lack of secondary grooves; shells can, however, be very similar. Identification of males of N. apicina can be confirmed by the longer rod-pieces of the paraspermatozoa and the form of the penis, which has a more projecting glandular disc and rounded tip to the filament. The usual black (or grey) and white color of N. tenuistriata is generally dis- tinctive, but pale examples might be confused with UN. paytensis; the shell of N. tenuistriata is usually larger and broader than that of N. paytensis, with similarly narrow ribs but stronger grooves (which never become obsolete) on the last whorl, and the penial glandular disc is larger. Small shells and juveniles (less than 6 mm) with dark coloration (e.g., Figure 12R) can easily be confused with brown adult NV. santelenae, with which they can be mi- crosympatric among barnacles. Separation is achieved by the rounded periphery and more patulous shape of N. santelenae, which has fine microstriae and may develop raised ribs, contrasting with the smooth, glossy surface and incised spiral lines of N. paytensis. There has been a history of confusion of N. paytensis with the southern N. araucana; these two are restricted to the Panamic and Peruvian Provinces respectively, but in the transitional zone they may occur sympatrically (e.g., records of both from Paita and Pimentel by Peja, 1970). The shell of the latter species is smaller with a more rounded periphery and slightly produced anterior lip; the color pattern is also variable but never shows axial series of dots; most usefully, the interior of the ap- erture shows a single pale basal band (two in N. payten- sis) and in addition penial shape is diagnostic. Remaining Nodilittorina Species The remaining species in the eastern Pacific Ocean (N. araucana, N. peruviana, N. galapagiensis, N. fernande- zensis) form a heterogeneous group. The two southern species, N. araucana and N. peruviana, share some sim- ilarities in their shell shape, sculpture, and color pattern, but anatomical characters differ significantly. The Gala- pagos endemic, N. galapagiensis, is the only nodulose species in the region and has a unique penial shape. The last species, N. fernandezensis, 1s endemic to the Islas Juan Fernandez and Desventuradas off Chile, and is clearly related to a group of species in the southern Pa- cific rather than to any others in the eastern Pacific. Nodilittorina araucana (d’Orbigny, 1840) (Figures 16G, H, 18A—J, 19A—C, E H, J, K, 20) Littorina araucana d’Orbigny, 1840:393-394; Atlas (1840) pl. 53, figs. 8-10 (Valparaiso, Chili, also entire coast as far as Arica, Pérou [ Valparaiso, Chile, to Arica, Chile]; here restricted to Valparaiso, the locality of the types; lectotype (here designated, 7.0 X 4.7 mm) BMNH 1854.12.4.365/1, seen, Figure 181; 12 paralectotypes BMNH 1854.12.4.365/2, seen, 1 is probably not this species). Hupé, 1854:138. Reeve, 1857:sp. 88, pl. 16, fig. 88. Dall, 1909:231, 285 (in part, includes N. pay- tensis). Keen, 1971:365. Litorina araucana—Philippi, 1847:2:197, Litorina pl. 4, fig. 5. Kiister, 1856:17, pl. 2, figs. 21, 22 (1856). Weinkauff, 1878:30 (as auracana). Weinkauff, 1883:219. Strebel, 1907:155—156. Littorina (Melaraphe) araucana—H. & A. Adams, 1854: 314. Littorina (Austrolittorina) araucana—Rosewater, 1970:423. Dell, 1971:205. Marincovich, 1973:25, figs. 48, 49. Al- amo & Valdivieso, 1987:25. Alamo & Valdivieso, 1997: 17. Nodilittorina (Nodilittorina) araucana—Reid, 1989a:99 (N. paytensis a doubtful synonym). Skoglund, 1992:15 (N. paytensis a doubtful synonym). Nodilittorina araucana—Finet, 1994:18, 127 (N. paytensis doubtfully included). Reid & Osorio, 2000:123, fig. 7C. Littorina thersites Reeve, 1857:sp. 78, pl. 15, figs. 78a, b (Valparaiso [Chile]; 4 syntypes BMNH 1968317, Figure D. G. Reid, 2002 18C, seen). Weinkauff, 1882:69, pl. 9, figs. 5, 8. Wein- kauff, 1883:219. Dall, 1909:231. Littorina (Melaraphe) thersites—Tryon, 1887:252, pl. 45, fig. 18 (doubtfully placed in synonymy of L. (M.) ner- itoides). Littorina (Melaraphe) paytensis—Tryon, 1887:250, pl. 45, figs. 95, 96 (in part, includes N. paytensis). Taxonomic history: The shell of this species is highly variable; d’Orbigny’s (1840) species was based on elon- gate, faintly striated, brown shells, and that of Reeve (1857) on low-spired, grooved, blue-grey shells, although both collections were from Valparaiso. One of the para- lectotypes of L. araucana is probably not this species; it bears fine oblique axial stripes over the whole whorl width, but is too eroded for certain identification. The name thersites has seldom been used; Weinkauff (1882, 1883) and Dall (1909) both accepted it as a distinct spe- cies, whereas Tryon (1887) doubtfully placed it in the synonymy of the European Melarhaphe neritoides. In Peru and Chile N. araucana is well known. The only taxonomic confusion has arisen from its superficial sim- ilarity to some shells of N. paytensis, a species that was doubtfully included in the synonymy of N. araucana by Reid (1989a, followed by Finet, 1994); Tryon (1887) dis- regarded priority and used the name paytensis for this species. Diagnosis: Shell small, whorls rounded, spire profile straight to slightly convex, periphery rounded; slightly produced anterior lip; six to 10 primary spiral grooves; sculpture of numerous fine grooves (up to 29 in total on last whorl), but often obsolete on last whorl; white to dark brown, pale basal band; single pale basal band within brown aperture. Penial filament broad, with subterminal opening of sperm groove; mamilliform gland and small glandular disc borne on projection of base. Material examined: 52 lots (including 16 penes, 6 sperm samples, 6 pallial oviducts, 2 spawn samples, 4 radulae). Shell (Figures 18A-—J): Mature shell height 1.5-13.8 mm. Shape globular to elongate (H/B = 1.13-1.89, SH = 1.39—2.38); spire whorls rounded, suture distinct; spire profile straight to slightly convex; periphery usually rounded, sometimes angled. Columella concave to straight, slightly hollowed and pinched at base, anterior lip often slightly produced; small eroded parietal area. Sculpture of 6—10 primary spiral grooves on spire whorls, slightly more closely spaced posteriorly; secondary sculp- ture may start early, on last whorl up to 29 grooves in total (including base), irregularly spaced, grooves usually remain as incised lines, exceptionally equal to width of intervening ribs, peripheral rib may be sightly raised; more frequently sculpture becomes obsolete above pe- riphery on last whorl, or over entire whorl; spiral mi- crostriae absent; spire frequently eroded. Periostracum relatively thick, slightly overhanging apertural edge. Pro- toconch 0.37 mm diameter, about 3 whorls. Color white Page 143 to blue-grey to black-brown; dark brown shells may be paler near suture and on base, with white basal band; definite color pattern usually limited to white basal band, occasionally broken up into spots, and rarely with coarse white marbling over entire base; exceptionally 1—2 white spiral bands above periphery at end of last whorl and 2 below (including normal basal band); axial pattern rarely present, never showing distinct opisthocline oblique stripes, but limited to differentially colored growth lines, or slightly wavy lines along prosocline growth incre- ments; aperture brown, with single pale spiral band at base; columella brown. Animal: Head and tentacles black, pale only around eye; sides of foot dark grey to black. Opercular ratio 0.38— 0.50. Penis (Figures 19A—C): filament broad, glandular at base, sometimes reddish at tip, 0.6—0.7 total penial length; sperm groove appears to end subterminally at about 0.7 filament length (although in fact it continues as a shallow trace to the tip), so that filament abruptly narrows behind tapered tip; glandular disc small, smaller than moderate mamilliform gland, borne on projection of base; penis with black pigment at base. Euspermatozoa 64-71 pm (80-100 ym, Jordan & Ramorino, 1975); paraspermato- zoa (Figures 19J, K) oval to fusiform, 16—40 wm (35 wm, Jordan & Ramorino, 1975), packed with spherical gran- ules that become smaller toward one (often pointed) end; no rod-pieces visible. Pallial oviduct (Figure 19H) with slight flexure in path of egg groove through opaque cap- sule gland, copulatory bursa sometimes very large, open- ing near posterior end of straight section, extending back almost to albumen gland. Spawn (Figure 19F) an asym- metrically biconvex pelagic capsule, 210—256 «wm diam- eter, with broad vertical peripheral rim, single ring on domed upper surface, containing single ovum 68—84 1m diameter (Jordan & Ramorino, 1975). Development planktotrophic (Jordan & Ramorino, 1975). Radula (Figures 16G, H): Relative radular length 1.5— 3.5. Rachidian: length/width 1.23—1.45; major cusp mod- erately elongate, rounded at tip. Lateral and inner mar- ginal: major cusps elongate, rounded or blunt at tip. Outer marginal: 7—8 cusps. Habitat: Throughout most of its range, this species is abundant and characteristic of the bare littoral fringe and uppermost barnacle zone, on both exposed and sheltered rocky coasts (Alveal, 1970, 1971; Romo & Alveal, 1977; Santelices et al., 1977; Ruiz & Giampaoli, 1981). How- ever, at the southern extreme of its range, in the Chilean Archipelago, it has been reported to occur commonly both in the littoral fringe and throughout the eulittoral zone (Dell, 1971; Alveal & Romo, 1977; Brattstrém, 1990; Reid & Osorio, 2000), among barnacles, tufts of red algae Hildenbrandia and Iridaea, filamentous green algae, beds of Mytilus and Perumytilus, and in shallow pools of the upper eulittoral. Most of these southern ob- Page 144 The Veliger, Vol) A5; Now D. G. Reid, 2002 Page 145 servations have been made on sheltered shores, whereas on exposed shores in the region the zonation is apparently more typical, among the uppermost barnacles and Hil- denbrandia (Reid & Osorio, 2000). The species is often sympatric with N. peruviana, with which it may overlap in the upper barnacle zone, but N. araucana extends to higher levels in the littoral fringe (Guiler, 1959b; Alveal, 1970, 1971; Santelices et al., 1977; Brattstr6m, 1990). Of these two species, N. araucana has been said to be the more common in exposed sites (Romo & Alveal, 1977), but Marincovich (1973) reported that it was absent on the most wave-exposed coasts in the vicinity of Iquique. Range (Figure 20): Peru and Chile. Range limits: Paita, Piura, Peru (Alamo & Valdivieso, 1987, 1997; in view of possible confusion with N. paytensis this record might be doubted); Salaverry, La Libertad, Peru (USNM 667199); Forelius Peninsula, Aisen, Chile (BMNH 20001261). Dall (1909) gave the range as Isla Chiloé to Nicaragua, and this northern limit has been quoted by others (Carcelles & Williamson, 1951; Dell, 1971; Alamo & Valdivieso, 1987, 1997); it is undoubtedly incorrect and may partly be explained by the fact that Dall (1909) included N. pay- tensis in his concept of araucana, although even that spe- cies is not recorded farther north than Costa Rica. Remarks: This species covers a range of latitude from at least 8 to 47°S, and therefore extends throughout the Peruvian Province, including the transitional zone with the southern Magellanic Province. Shell form, sculpture, and color are remarkably variable, and indeed Reeve (1857) described the low-spired, striated, blue-grey form as a species distinct from the taller, smoother brown shells originally described by d’Orbigny (1840). Nevertheless, such variation is common among Nodilittorina species, as repeatedly shown in those from the eastern Pacific. Furthermore, intergradation between extreme forms is found at most localities, as also noted by Marincovich (1973). It is not known if there are microenvironmental correlates of the shell variation within localities. How- ever, there appears to be a geographical component to color variation. Of the material examined in the present study all 19 collections from south of Valparaiso consist- ed éntirely of brown shells. Only at Valparaiso (33°S) and northward were some blue-grey to white shells found (in 50% of the 26 samples seen), usually mixed with shells of variably brown hue. One possible explanation is that at lower latitudes there is climatic selection in favor of pale shells, which reach lower temperatures in sunlight (see Markel, 1971, for temperature measurements of dark N. dubiosa and white N. conspersa). Hughes (1979) de- scribed a supposedly intraspecific geographical cline from dark brown to blue-grey shells with decreasing latitude along the east coast of South Africa, although it is now known that two distinct species are involved (dark N. knysnaensis and pale N. africana; unpublished observa- tions). Note that in dry museum collections the brown color of the shell fades to beige. This species is unlikely to be confused with its fre- quently sympatric but much larger congener N. peruvi- ana, except when the latter is small and lacking its strik- ing zebra pattern (see Remarks on N. peruviana). Simi- larity to N. paytensis, with which it is occasionally sym- patric in northern Peru, has been discussed in the Remarks on that species. The relationships of N. araucana are unclear. Some features, such as the tendency toward a smooth shell, rather irregular pattern (even if often restricted to the base), shape of the aperture, and form of the spawn re- semble the sympatric N. peruviana. However, in other respects N. araucana does not appear to be closely related to other Nodilittorina species from Central and South America. The peculiar subterminal opening of the sperm groove and slight flexure in the capsule gland are unusual, while the form of the paraspermatozoa is, so far as is known, unique in the genus. A similar penial shape is seen in N. riisei (M@rch) from the Caribbean and also in N. unifasciata from Australia (but the slight flexure of the egg groove in the capsule gland of N. araucana does not closely resemble the large loop in this position in mem- bers of Austrolittorina, see Remarks on N. fernandezen- SiS). Figure 18. Shells of Nodilittorina araucana (A—J), N. peruviana (K—P), and N. fernandezensis (Q—-V). A. Tubul, _Bio-Bio, Chile (BMNH 20001262). B. Isla Acuaco, Aisen, Chile (BMNH 19990379). C. Syntype of Littorina thersites Reeve, 1857; Valparaiso, Chile (BMNH 1968317). D. Mollendo, Arequipa, Peru (BMNH 1938.7.11.56). E. Las Cruces, Valparaiso, Chile (BMNH 20001263). EK G. Coquimbo, Chile (BMNH 1886.6.9.259, 260). H. Los Vilos, Coquimbo, Chile (BMNH 20001264). I. Lectotype of Littorina araucana d’Orbigny, 1840; Valparaiso, Chile (BMNH 1854.12.4.365/1). J. Taltal, Antofagasta, Chile (USNM 713998). K. Valparaiso, Chile (BMNH 20001267). L. Locality unknown (BMNH 20001268). M. Locality unknown (BMNH 20001269). N. Lectotype of Phasianella peruviana Lamarck, 1822; Callao, Lima, Peru (MHNG 1096/86-1). O. Salaverry, La Libertad, Peru (USNM 667199). P. Las Cruces, Valparaiso, Chile (BMNH 20001270). Q. Isla Alejandro Selkirk, Archipiélago de Juan Fernandez (BMNH 20001278). R, S. Punta San Carlos, Isla Robinson Crusoe (Mas a Tierra), Archipiélago de Juan Fernandez (BMNH 20001279). T. Holotype of Littorina unifasciata fernandezensis Rosewater, 1970; Bahia Cum- berland, Isla Mas a Tierra, Archipiélago de Juan Fernandez (USNM 368900). U. Locality unknown (BMNH 1914.5.8.6). V. Isla San Felix, Islas Desventuradas (BMNH 20001280). Scale bars A-J = 5 mm; K—V = 5 mm. D. G. Reid, 2002 Nodilittorina peruviana (Lamarck, 1822) (Figures 16E 18K—P, 19D, E, G, I, L, M, 20) Phasianella peruviana Lamarck, 1822:53 (les cotes du Pér- ou, pres de Callao [Callao, Peru]; lectotype (here des- ignated) MHNG 1096/86-1, 16.7 < 11 mm, Figure 18N; 1 paralectotype MHNG 1096/86-2; 1 lost paralec- totype figured by Delessert, 1841:pl. 37, fig. 9a, b). De- lessert, 1841:pl. 37, fig. 9a, b. Deshayes & Milne Ed- wards, 1843:243. Littorina peruviana—Gray, 1839:138, pl. 36, fig. 8 (includes Littorina striata King & Broderip, 1832 in synonymy). d’Orbigny, 1840:393, pl. 53, figs. 5—7. Hupé, 1854:137— 138. Stearns, 1893b:444. Dall, 1909:172—173, 231, 285, pl. 23, fig. 7. Vegas, 1968:7—8. Keen, 1971:366, fig. 185. Finet, 1985:9, 13. Littorina (Melaraphe) peruviana—H. & A. Adams, 1854: 314. Tryon, 1887:249, pl. 44, fig. 78. Litorina peruviana—Weinkauff, 1883:221. Littorina (Austrolittorina) peruviana—Rosewater, 1970:423. Marincovich, 1973:26, fig. 50. Basly, 1983:18, pl. 4, fig. 34. Alamo & Valdivieso, 1987:25, fig. 36. Alamo & Valdivieso, 1997:17, fig. 36. Nodilittorina peruviana—Bandel & Kadolsky, 1982:14. Fi- net, 1994:18. Nodilittorina (Echinolittorina) peruviana—Reid, 1989a:99. Skoglund, 1992:15. Kaiser, 1997:27. Turbo zebra Wood, 1828:20, pl. 6, Turbo fig. 33 (S. Amer- ica; here restricted to Arica, Chile, the locality of the syntypes; 18 syntypes, BMNH 1968367, seen). Litorina zebra—Philippi, 1847:2:165, Litorina pl. 3, fig. 16. Kiister, 1856:18-19, pl. 2, figs. 25-27 (1853). Wein- kauff, 1878:31. Littorina zebra—Reeve, 1857:sp. 61, pl. 12, fig. 61a, b. Troschel, 1858:134, pl. 11, fig. 2 (radula). Littorina zebra var. nana Nevill, 1885:140 (Valparaiso [Chile]; nomen nudum). Taxonomic history: This well known species is suffi- ciently distinctive that it has not been confused with any other. In the early literature the junior synonym zebra was commonly employed by German and English authors (an exception was Gray, 1839), but following the revisions of Weinkauff (1883) and Tryon (1887) the earlier peru- viana prevailed. Diagnosis: Shell large, whorls rounded, spire profile con- cave near apex, periphery rounded; slightly produced an- terior lip; spiral sculpture usually absent; white with few broad irregular waved axial black stripes; single pale bas- Page 147 al band within brown aperture. Penial filament long; ma- milliform gland and large glandular disc borne on pro- jection of base. Material examined: 63 lots (including 11 penes, 5 sperm samples, 4 pallial oviducts, 4 radulae). Shell (Figures 18K—P): Mature shell height 6.0 mm (Jor- dan & Ramorino, 1975)—23.8 mm. Shape high turbinate (H/B = 1.31—1.88, SH = 1.46—1.93); spire whorls round- ed, suture distinct; spire profile concave near apex, but often eroded; periphery rounded, or only slightly angled in some juveniles. Columella long, concave to straight, slightly hollowed and pinched at base, anterior lip often slightly produced; no eroded parietal area. Spiral sculp- ture usually absent, even on early whorls; sometimes 1— 4 (rarely 6-8) faint incised lines above periphery; occa- sionally a slightly enlarged rib forms an angle at periph- ery; spiral microstriae absent. Periostracum relatively thick, sometimes slightly overhanging apertural edge. Protoconch not seen. Color white with dark brown or black broad, waved or irregular axial stripes; sometimes entirely black or with only an interrupted white basal band; aperture purplish black, with single pale spiral band at base; columella brown to black. Animal: Head and tentacles black, pale around eye and sometimes at inside of tentacle base; sides of foot dark grey to black. Opercular ratio 0.36—0.43. Penis (Figures 19D, E): filament long when fully relaxed, 0.7—0.8 total length, sperm groove open to tip; glandular disc large, often projecting, borne with mamilliform gland on pro- jection of base; penis unpigmented or slightly pigmented at base. Euspermatozoa 57—64 wm (65-80 xm, Jordan & Ramorino, 1975); paraspermatozoa (Figures 19L, M) oval, 11-18 pm (25 pm, Jordan & Ramorino, 1975), filled with large round granules, often an apparent nucleus visible, rod-pieces variable within individuals, single or multiple, short and rectangular or long slender and pro- jecting, up to 28 pm long. Pallial oviduct (Figure 191) with copulatory bursa opening near posterior end of straight section and extending back to albumen gland. Spawn (Figure 19G) an asymmetrically biconvex pelagic capsule, 336—421 jm diameter, with broad and slightly oblique peripheral rim, 1—2 rings on domed upper sur- face, containing single ovum 84—89 p.m diameter (Jordan Figure 19. Penes (A-E), egg capsules (EK G), pallial oviducts (H, I), and paraspermatozoa (J—-M) of Nodilittorina araucana (A-C, FH, J, K) and N. peruviana (D, E, G, I, L, M). A. Isla Acuaco, Aisen, Chile (BMNH 19990379; shell H = 7.2 mm). B, C, H, J. Las Cruces, Valparaiso, Chile (BMNH 20001263; shell H = 7.0 mm, 6.7 mm, 8.2 mm). D. Playa La Lisera, Arica, Tarapaca, Chile (BMNH 20001271; shell H = 11.9 mm). E, I. Caleta Catarindo, Arequipa, Peru (BMNH 20001272; shell H = 11.9 mm, 13.0 mm). K Montemar, Valparaiso, Chile (after Jordan & Ramorino, 1975). G. Montemar, Valparaiso, Chile (after Jordan & Ramorino, 1975). K. Concepcion, Bio-Brio, Chile (BMNH 20001265). L, M. Las Cruces, Valparaiso, Chile (BMNH 20001270). Abbreviation: tp, termination of deep part of penial sperm groove (continues as a shallow trace to tip). Shading conventions as in Figures 3, 4, 13. Scale bars: A-E = | mm; E G = 0.1 mm; H, I = 1 mm; J—M = 20 pm. The Veliger, Vol. 45, No. 2 Page 148 110° 100° 90° 80° 70° 60° 10° Lt 10° O° 0° 10° 10° 20° 20° 30° 30° f { 40° f 40° t ? B 5 bs @ N. araucana a A Alamo & Valdivieso (1987, 1997) ey © N. peruviana B Brattstrém & Johanssen (1983) * N. galapagiensis * N. fernandezensis 60° 60° 110° 100° 90° 80° 70° 60° Figure 20. Geographical distribution of Nodilittorina araucana, N. peruviana, N. galapagiensis, and N. fernandezensis (records based on material examined and quoted literature sources). D. G. Reid, 2002 Page 149 & Ramorino, 1975). Development planktotrophic (Jordan & Ramorino, 1975). Radula (Figure 16F): Relative radular length 2.8—3.4. Rachidian: length/width 1.34—1.41; major cusp elongate, rounded at tip. Lateral and inner marginal: major cusps elongate, rounded at tip. Outer marginal: 7—10 cusps. Habitat: Abundant on rocky coasts, both exposed and sheltered, but favoring strong wave-exposure; typically in upper part of barnacle zone, extending into littoral fringe in areas with heavy spray; also among Perumytilus; often sympatric with N. araucana, but zoned slightly below that species (Guiler, 1959a, b; Vegas, 1963; Alveal, 1970, 1971; Marincovich, 1973; Paredes, 1974; Romo & AI- veal, 1977; Santelices et al., 1977; Brattstr6m, 1990). The algal diet has been studied by Santelices & Ugarte (1987). Range (Figure 20): Peru and Chile. Range limits: Paita, Piura, Peru (USNM 6029, 2 specimens; Stearns, 1891; Vegas, 1963; Pena, 1970; Alamo & Valdivieso, 1987, 1997); Isla Lobos de Tierra, Piura, Peru (USNM 538007, 4 specimens; Alamo & Valdivieso, 1987, 1997); Isla Lo- bos de Afuera, Lambayeque, Peru (USNM 753012, 4 specimens); Navidad, Santiago, Chile (ZMA); Rio Bio- Bio, Concepcion, Chile (BMNH 20001266, 1 specimen); Isla Chiloé, Chile (USNM 348499, 2 specimens); Golfo de Ancud, 41°49'S, Chile (Brattstr6m & Johanssen, 1983). Records include islands such as Isla Lobos de Afuera (60 km from the mainland). This species appears to be scarce south of the Santiago Region, from which only three museum specimens have been seen, whereas N. araucana is relatively frequently represented from the same area. Brattstr6m (1990) observed that it was uncom- mon in Seno Reloncavi (southern Chile). The northern- most record from Paita is based on an old sample in USNM, but the locality is confirmed by the authors quot- ed above. This locality is close to the northern limit of the influence of the cold Peru Current (see Discussion). Two old collections from the Galapagos Islands (USNM 60661; USNM 132798) are apparently the basis for the records by Stearns (1893b) and Dall (1909) that have been quoted by subsequent authors (Keen, 1971; Finet, 1985; Alamo & Valdivieso, 1987, 1997). Finet (1994) doubted the provenance of the specimens, yet curiously accepted the literature records based on them. He there- fore counted the species as one of only three “‘purely Peruvian” members of the Galapagos fauna (Finet, 1991, 1994). Occurrence in the Galapagos has not been verified by any recent records, despite considerable collecting ef- fort, and is here regarded as unlikely. Dall (1909) also mentions the species from Nicaragua and Panama, where it certainly does not occur. Remarks: The large size and strikingly colored, smooth shell of this species are so distinctive that confusion of typical specimens with any other species is not likely. Juveniles can be confused with the smaller sympatric WN. araucana if they have entirely black shells; such shells are recognized by the delicate apertural edge (indicating that they are juvenile) and their distinctively concave spire profile. The possible relationships of this species are unclear. While the shell shows some similarity to that of N. ar- aucana in its frequently smooth surface, apertural shape, and irregular pattern, and in egg capsule morphology, the anatomical differences in paraspermatozoa and _ penial shape are likely to be more significant. Nodilittorina pe- ruviana is similar to the members of the N. aspera group in the form of the penis, oviduct, and paraspermatozoa, but these are all of types common throughout the genus and so do not necessarily indicate close relationship. Nodilittorina galapagiensis (Stearns, 1892) (Figures 7L—Q, 20, 21A—E K, M, N, 22A, B) Hamus lemniscatus—Wimmer, 1880:32 (not Littorina lem- niscata Philippi, 1846 = N. miliaris (Quoy & Gaimard, 1833)). Tectarius lemniscatus—Stearns, 1893b:397, 444 (not Philip- pi, 1846). Hamus trochoides—Wimmer, 1880:32—33 (not Littorina tro- choides Gray, 1839 = N. trochoides). Tectarius trochoides—Stearns, 1893b:397, 444 (not Gray, 1839). Littorina (Tectarius) galapagiensis Stearns, 1892:87—88 (James Island [Isla Santiago, Galapagos]; holotype USNM 102509, Stearns, 1892:pl. 51, fig. 7, Figure 7L herein, seen). Stearns, 1893b:396-—397, pl. 51, fig. 7. Tectarius galapagiensis—Pilsbry & Vanatta, 1902:553. Dall, 1909:232. Hertlein & Strong, 1939:371. Hertlein & Strong, 1955a:137. Nodilittorina (Nodilittorina) galapagiensis—Rosewater, 1970:424. Reid, 1989a:99. Skoglund, 1992:15. Kaiser, 1993:106. Kaiser, 1997:27. Nodilittorina galapagiensis—Keen, 1971:367, fig. 190. Hertz, 1977:29, fig. Taviani, 1979:14, figs. LOA, B, 11. Finet, 1985:13. Finet, 1994:18. Tectarius atyphus Stearns, 1891:326 (nomen nudum). Littorina (Tectarius) atyphus Stearns, 1892:88—89 (Manta, Ecuador; holotype USNM 48396, seen). Tectarius atyphus—Stearns, 1893a:350, pl. 50, fig. 5. Taxonomic history: This nodulose shell was confused with similar forms from the Atlantic and West Pacific by Wimmer (1880; quoted by Stearns, 1893b). It is surpris- ing that Stearns (1892) should have described this species twice, as galapagiensis and atyphus, in the same publi- cation. However, he possessed only single specimens of each, and the latter was a more elongate, less nodulose beachworn shell, said to have originated from Manta on the mainland of Ecuador. Only Stearns (1891, 1892, 1893a) employed the name atyphus; subsequent authors (following Pilsbry & Vanatta, 1902, as first revisers) have recognized its synonymy with N. galapagiensis. Like oth- er members of Nodilittorina with nodulose sculpture, this has in the past sometimes been placed in the genus Tec- tarius (= Hamus; see Rosewater, 1972; Reid, 1989a). D. G. Reid, 2002 Diagnosis: Shell small; sculpture of nodulose or granu- lose cords; dark brown to black with white band on base, nodules whitish, especially on base. Penial filament with hooked tip, subterminal opening of sperm groove; small mamilliform gland and small glandular disc borne on nar- row projection of base; a second mamilliform gland on medial side of filament, behind tip. Material examined: 33 lots (including 12 penes, 3 sperm samples, 4 pallial oviducts, 4 radulae). Shell (Figures 7L—Q): Mature shell height 3.5—13.1 mm. Shape turbinate to high turbinate (H/B = 1.23-1.79, SH = 1.58—2.19); spire whorls usually rounded, suture dis- tinct, sometimes flattened and with indistinct suture; spire profile straight; periphery rounded or angled, marked by nodulose rib. Columella short, concave, hollowed, and slightly pinched at base, anterior columellar lip slightly flared; small eroded parietal area. Sculpture of 3 spiral rows of nodules (at periphery, shoulder and, smaller, near suture); base with 2—5 nodulose or granulose cords; nod- ules usually large, but may be reduced in size to give granulose rather than nodulose appearance to shell, oc- casionally reduced to mere undulations on fine spiral rib- lets numbering about 20 on last whorl; entire surface cov- ered with fine spiral microstriae grading into riblets. Pro- toconch 0.26 mm diameter, 2.8 whorls. Color dark brown to black, nodules often paler brown or, on base, whitish; spiral cream band on base and often a pale line on shoul- der, sometimes also at suture; aperture dark brown, pale spiral band at base; columella purplish brown. Animal: Head black; tentacle with 2 broad black longi- tudinal stripes, pale around eye, at tip and at inside of tentacle base; sides of foot black. Opercular ratio 0.44— 0.60. Penis (Figures 21A-—F): filament wrinkled at base, about 0.5—0.6 total length, dilated distally with hooklike tip, opening of sperm groove subterminal on raised pro- jection; small glandular disc and small mamilliform gland on narrow projection of base; second mamilliform gland on medial surface of distal part of filament, surrounded by glandular subepithelial tissue; penis unpigmented. Euspermatozoa 39-43 jm; paraspermatozoa (Figures 21M, N) oval with single long straight (or slightly curved) blunt projecting rod-pieces, 16-25 jm, cyto- Page 151 plasm filled with large round granules. Pallial oviduct (Figure 21K) with copulatory bursa opening near poste- rior end of straight section and extending back to albumen gland. Spawn not observed. Protoconch indicates plank- totrophic development. Radula (Figures 22A, B): Relative radular length 1.6— 5.5. Rachidian: length/width 1.39—1.57; major cusp elon- gate, pointed or slightly rounded at tip. Lateral and inner marginal: major cusps elongate, rounded or pointed at tip. Outer marginal: 9-10 cusps. Habitat: Abundant on boulders, rocks and cliffs of lava, also on volcanic tuff and on concrete; on bare surfaces in littoral fringe and uppermost eulittoral zone, also in crevices and at edges of saline pools; on exposed and sheltered shores. This is the only abundant littorinid of the littoral fringe in the Galapagos Islands; sympatric WN. conspersa, N. atrata, and N. porcata are all found at low- er levels. For descriptions of zonation see Cinelli & Co- lantoni (1974, as Tectarius galapagiensis); these authors also record occurrence on mangrove trunks. Range (Figure 20): Probably endemic to the Galapagos Islands; a single record from mainland Ecuador (Stearns, 1891, 1892) has not been confirmed. Range limits: Caleta Iguana, Isla Isabela (USNM 796177); NE side Isla Fer- nandina (LACM AHF 153-34); Punta Egas, Isla Santiago (USNM 807237); Isla Bartolomé (USNM 707612); Isla Genovesa (personal observation); Puerto Ayora, Isla San- ta Cruz (USNM 769823; BMNH 20001273); Punta Pitt, Isla San Cristobal (personal observation); Bahia Gardner, Isla Espanola (CDRS); Punta Cormorant, Isla Santa Maria (personal observation). Stearns (1891, 1892) recorded a single specimen from Manta on the mainland of Ecuador (as Tectarius atyphus; USNM 48396), said to have been collected there by W. H. Jones. Since then, no further specimens are known to have been collected on the main- land. It is possible that some error of labeling occurred, for in the same month (August 1884) the navy surgeon visited both Manta and the Galapagos Islands. Remarks: Specimens with well developed nodules can- not be mistaken for any other littorinid from the region. Small, relatively smooth specimens might be confused with brown shells of the sympatric N. atrata and N. por- Figure 21. Penes (A—J), pallial oviducts (K, L), and paraspermatozoa (M-—P) of Nodilittorina galapagiensis (A-F K, M, N) and N. fernandezensis (G—J, L, O, P). A-D, K, M, N. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (BMNH 20001273; shell H = 6.0 mm, 4.6 mm, 6.5 mm, 8.8 mm; A, B, two views). E, FE Punta Estrada, Isla Santa Cruz, Galapagos Islands (E, BMNH 20001274, shell H = 7.4 mm; K BMNH 20001276, shell H = 6.9 mm). G. Punta San Carlos, Isla Robinson Crusoe (Mas a Tierra), Archipiélago de Juan Fernandez (BMNH 20001279; shell H = 12.8 mm). H. Isla San Ambrosio, Islas Desventuradas (BMNH 20001281; shell H = 17.0 mm), I, J, L, O, P. Bai del Oueste, Isla Robinson Crusoe (Mas a Tierra), Archipiélago de Juan Fernandez (BMNH 20001282; shell H = 7.5 mm, 10.7 mm, 13.7 mm). Abbreviations: pg, mamilliform penial gland in normal position; pg2, second mamilliform penial gland; tp, termination of penial sperm groove. Shading conventions as in Figures 3, 4, 13. Scale bars: A-L = 1 mm; M-P = 20 pm. Page 152 ithe Veligers Voll45: Now D. G. Reid, 2002 Page 153 cata, but both of these usually have a lower spire and a large pseudo-umbilicus. Stearns (1892, 1893a, b) de- scribed nodulose and granulose forms under different names, and the variability in development of nodules was noted by Taviani (1979). The nodulose shell is very distinctive and unlike that of any other eastern Pacific species, while it superficially resembles such nodulose Atlantic species as N. dilatata, N. miliaris, and N. granosa (Philippi). However, sculpture is so variable within many Nodilittorina species that it appears to be an unreliable guide to relationships. Of more significance is the penis which, with its unusual subterminally opening sperm groove and unique second mamilliform gland, does not closely resemble that of any other species. Nodilittorina (Austrolittorina) fernandezensis (Rosewater, 1970) (Figures 18Q—V, 20, 21G—J, L, O, P, 22C, D) Littorina penitaria ““Wood” Nevill, 1885:142 (San Juan Fer- nandez [Juan Fernandez Islands]; nomen nudum). Littorina mauritiana—Odhner, 1922:223. Rozbaczylo & Castilla, 1987:176. (Both not Phasianella mauritiana Lamarck, 1822 = Littoraria mauritiana.) Littorina (Austrolittorina) unifasciata fernandezensis Rose- water, 1970:471—472, pl. 359, figs. 9-12, pl. 361, fig. B (radula) (east shore of Cumberland Bay, Isla Mas a Tierra, Juan Fernandez Islands [Chile]; holotype USNM 368900, Rosewater, 1970, pl. 359, figs. 11, 12, Figure 18T herein, seen; 25 paratypes USNM 679256, seen; 11 paratypes DMNH 039221, not seen). Nodilittorina (Nodilittorina) fernandezensis—Reid, 1989a: 99. Nodilittorina fernandezensis—Ramirez & Osorio, 200:1—13. Taxonomic history: Although Nevill (1885) ascribed the name penitaria to W. Wood on the basis of a museum label of unknown provenance, it was apparently never published. The name was rejected as a nomen nudum by Rosewater (1970), although arguably the locality alone, as given by Nevill (1885), was sufficient to unambigu- ously identify the species, since no other member of the family occurs there. This species is abundant on the is- lands of the Juan Fernandez and Desventuradas archipel- agos, but these are so remote that it is very rare in mu- seum collections and has scarcely been mentioned in the literature. Odhner (1922) misidentified it as mauritiana, a member of the genus Liftoraria with a superficially sim- ilar greyish white shell. Rosewater (1970) introduced the name as a subspecies of the Australian N. unifasciata, correctly recognizing N. fernandezensis as a member of the Austrolittorina group. Diagnosis: Shell large, whorls rounded, spire profile Straight, periphery only slightly angled; aperture finely lirate; spiral sculpture of fine microstriae only; white with broad indistinct blue-grey zone above periphery; single pale basal band within brown aperture. Penial filament small, pointed; small mamilliform gland and large glan- dular disc borne on projection of base. Material examined: 16 lots (including 15 penes, 3 sperm samples, 5 pallial oviducts, 4 radulae). Shell (Figures 18Q-V): Mature shell height 5.4—21.3 mm. Shape high turbinate (H/B = 1.37—1.87, SH = 1.42-— 2.09); spire whorls rounded, suture distinct; spire profile straight; periphery weakly angled, last whorl slightly flat- tened. Columella concave, weakly hollowed, slightly pinched at base; sometimes a small eroded parietal area; aperture finely lirate within outer edge. Spiral sculpture of 10-14 weak primary grooves above periphery on early whorls, but by last whorl these become less distinct and only slightly stronger than numerous fine spiral micros- triae across whole surface, so shell appears superficially smooth. Periostracum relatively thick, slightly overhang- ing apertural edge. Protoconch not seen. Color white with broad indistinct zone of blue-grey above periphery; smaller shells often with brownish axial growth marks, or pale brown with basal white band; aperture dark brown, with single pale spiral band at base; columella brown. Animal: Head and sides of foot black. Opercular ratio 0.37—0.60. Penis (Figures 21G—J): filament small, point- ed, 0.4—0.5 total length (but available specimens not re- laxed), terminal opening of sperm groove; mamilliform gland small, narrow, embedded in enlarged penial glan- dular disc, together borne on stout projection of base; penis slightly pigmented at base. Posterior 0.25 of pros- tate is swollen, reddish, closed as a duct; anterior part is thinner and an open groove. Euspermatozoa 66-71 p.m; paraspermatozoa (Figures 210, P) round, packed with granules, no visible rod-piece or nucleus, 11—15 wm di- ameter. Pallial oviduct (Figure 21L) with single loop of Figure 22. Radulae of Nodilittorina galapagiensis (A, B) and N. fernandezensis (C, D); juvenile shells of N. porcata (E; note periostracal hairs on basal ribs) and N. parcipicta (F); protoconch of N. modesta (G); sculpture of N. modesta (H; note absence of microsculptural striae). A, B. Punta Estrada, Isla Santa Cruz, Galapagos Islands (BMNH 20001276; two views of radula, flat and at 45°; shell H = 6.9 mm). C, D. Punta San Carlos, Isla Robinson Crusoe (Mas a Tierra), Archipiélago de Juan Fernandez (BMNH 20001279; two views of radula, flat and at 45°; shell H = 12.8 mm). E. Puerto Ayora, Isla Santa Cruz, Galapagos Islands (BMNH 20001169). EF 7 km N of San José del Cabo, Baja California Sur, Mexico (BMNH 20001179). G, H. Puerto Vallarta, Jalisco, Mexico (BMNH 20001197). Scale bars A-D, G = 50 pm; E, EK H = 0.5 mm. Page 154 The Veliger, Vol. 45, No. 2 albumen gland followed by large single loop of opaque capsule gland, terminating in reddish translucent portion; copulatory bursa opening at mid-point of straight section, extending back into capsule gland. Spawn not observed; form of oviduct indicates pelagic spawn and likely plank- totrophic development. Radula (Figures 22C, D): Relative radular length 2.3— 5.0. Rachidian: length/width 1.14—1.27; major cusp elon- gate, rounded at tip. Lateral and inner marginal: major cusps elongate, rounded or blunt at tip. Outer marginal: 7-9 cusps. Habitat: Volcanic rocks; abundant on rocks and in crev- ices, in highest intertidal zone, at densities of 65—430 per m? (Ramirez & Osorio, 2000). No other littorinids occur with this species. Range (Figure 20): Found only on the Islas Juan Fer- nandez and Islas Desventuradas off the coast of Chile. Range limits: Isla Robinson Crusoe (Isla Mas a Tierra), Archipiélago de Juan Fernandez (BMNH 20001279); Isla Alejandro Selkirk, Archipiélago de Juan Fernandez (BMNH 20001278); Isla San Felix, Islas Desventuradas (BMNH 20001280); Isla San Ambrosio, Islas Desventu- radas (BMNH 20001281). Remarks: The large, thick white shells of this species cannot be confused with any other in the eastern Pacific. However, medium and small examples are superficially similar to some pale specimens of N. araucana and N. paytensis. The former is distinguished by its lack of spiral microstriae, lack of lirae within the aperture, and (when present) stronger primary grooves. Nodilittorina payten- sis also lacks external microstriae and apertural lirae, has two pale stripes within the aperture, and almost always a pattern of small brown dots. Much more similar, and sometimes indistinguishable except by anatomical char- acters, are the New Zealand species N. antipodum (Phi- lippi) and the Australian N. unifasciata; where the locality is unknown, details of penial shape separate these three. Despite the superficial similarity to N. araucana and N. paytensis, the present species is not closely related to either of these. Rosewater (1970) recognized its relation- ships when he described it as a subspecies of the tem- perate Australian N. unifasciata (which he placed in Lit- torina, and included antipodum as another subspecies). Likely anatomical synapomorphies of these three species include the short and stout penial filament (although N. antipodum and N. unifasciata have a slightly subterminal opening of the sperm groove), the narrow mamilliform penial gland often partly embedded in the large penial glandular disc and, most importantly, the additional loop of the egg groove through the opaque capsule gland. This last character state unites a group of littorinids compris- ing, in addition to these three, N. cincta (Quoy & Gai- mard) from New Zealand, N. praetermissa (May) and N. acutispira (E. A. Smith) from southeastern Australia, and from South Africa N. africana (Philippi) and N. knys- naensis (Philippi). All eight species are here assigned to Austrolittorina Rosewater, 1970 (type species Littorina unifasciata). This is provisionally recognized as a sub- genus, although in the absence of strong synapomorphies for Nodilittorina it is not yet clear that this is correct, and the relationship of Austrolittorina with the rest of the ge- nus requires examination with molecular data. Another possible member of the Austrolittorina group is the east- ern Australian endemic N. pyramidalis; this shares the form of the pallial oviduct, but shows an unusual penial shape and is the only one with a nodulose shell. (It may be noted that since N. pyramidalis is the type species of Nodilittorina (subsequent designation by Abbott, 1954) its relationships and those of Austrolittorina have impor- tant consequences for the nomenclature of the entire ge- nus; see Remarks on Nodilittorina.) As originally consti- tuted, Rosewater’s subgenus contained many more spe- cies (including e.g., N. aspera, N. peruviana, smooth- shelled Atlantic Nodilittorina species, and Littoraria tessellata (Philippi)), and three more species were added later (Ponder & Rosewater, 1979). In revisions of the ge- neric classification of Littorinidae, both Bandel & Ka- dolsky (1982) and Reid (1989a) considered Austro- littorina a synonym of Nodilittorina. The subgenus Aus- trolittorina is here used in a restricted sense, and this group shows an austral distribution in temperate and warm temperate latitudes of the Southern Hemisphere. The shell of N. fernandezensis is among the thickest and most solid of all Nodilittorina species, but neverthe- less the large available samples show an unusually high frequency of scarring and repair on the shell (Figures 18R, T, V). This is more pronounced than in the similar N. unifasciata. Whether the shell damage is caused by unusually strong wave action, mobile boulders, or a pow- erful predator is unknown. DISCUSSION Intraspecific Shell Variation Using shell characters alone it would have been im- possible to resolve the taxonomy of the three species complexes of Nodilittorina in the eastern Pacific. How- ever, having defined the species largely by means of di- agnostic penial shapes it was possible to reexamine the confusing range of shell types and thus to discover tax- onomically useful characters. The key to interpreting shell variation is that, in each species group, the more obvious shell characters such as size, shape, development of ribs, and color show parallel variation within species, and that it is the more subtle differences in numbers of grooves and color pattern that discriminate between them. Using suitable characters, identification is in fact possible using shells alone in almost all cases. The degree of intraspecific variation (in shape, sculp- ture and color in the N. porcata group; in sculpture in the D. G. Reid, 2002 N. aspera and N. modesta groups and N. galapagiensis; and in shape and color in N. araucana) is remarkable, even among the notoriously polymorphic littorinids. In the well studied temperate genus Littorina, extreme intra- specific variability is associated with benthic spawn and a non-planktotrophic mode of development, whereas those species with pelagic egg capsules and planktotroph- ic development are less variable, at least on a local scale (review by Reid, 1996). The classic explanation for these observations is that the restricted gene flow in non-plank- totrophic species permits local genetic adaptation in re- sponse to differing selection regimes, resulting in distinc- tive shell forms or “‘ecotypes”’ that are characteristic of different microhabitats on the shore (e.g., Janson, 1983; Seeley, 1986; Johannesson et al., 1993; Trussell, 1997). Controlled rearing has confirmed that some shell traits are indeed heritable (Boulding & Hay, 1993; Johannesson & Johannesson, 1996; Parsons, 1997a). Striking local vari- ation is also known in some planktotrophic littorinids, such as the polymorphism of striated and nodulose forms of Littorina striata (Reid, 1996; de Wolf et al., 1997), Nodilittorina hawaiiensis (Rosewater & Kadolsky) (Struhsaker, 1968), and N. australis (Gray) (Johnson & Black, 1999). Although selection has sometimes been in- voked to account for this (Struhsaker, 1968), it would have to be very strong to explain the local-scale variation in the face of high gene flow. Alternative explanations also invoking a genotypic basis might involve non-ran- dom larval settlement or some means of limiting dispersal during the pelagic stage. However, there is now increas- ing evidence from laboratory rearing and field translo- cation that direct environmental effects on the phenotype play an important role. Examples of ecophenotypic ef- fects include the influences of food availability (mediated via its effect on growth rate) on shell shape (Kemp & Bertness, 1984; Boulding & Hay, 1993; Johnson & Black, 1998) and shell sculpture (Boulding et al., 1993), and the influence of crab predators and water temperature on shell thickness (Trussell, 1996, 2000). Although these demon- strations mostly involve non-planktotrophic littorinids, ecophenotypic effects have also been invoked to explain cases of local variation that are correlated with micro- habitat in planktotrophic species (Chapman, 1995; Reid, 1996; Johnson & Black, 1999). Indeed it is argued that in widely dispersed species occupying a range of habitats, phenotypic plasticity should be a favored strategy (Par- sons, 1997b). The evidence for phenotypic plasticity of shell traits in the eastern Pacific Nodilittorina species is largely indi- rect. In common with all known members of the genus, they produce pelagic egg capsules and undergo plankto- trophic development. (Although this has not been con- firmed by direct observation of spawn and protoconchs in every species, it is predicted from the universal asso- ciation of a large capsule gland in the pallial oviduct with planktotrophy in members of the Littorininae; Reid, Page 155 1989a.) Assuming that this results in high gene flow, the cases of shell variation between microhabitats on the same shore are difficult to explain except by phenotypic plasticity. The most striking examples are the contrasts between the smooth shells of N. atrata and N. santelenae from mid-shore rock pools and ribbed or carinate shells among barnacles on rocks close by. A possible explana- tion might be that faster growth under the more favorable conditions in pools results in a smoother shell (as shown in Littorina sitkana Philippi by Boulding et al., 1993). Other examples are the dwarf shells of N. aspera, N. ten- uistriata, and N. apicina found in small high-shore rock pools that are smaller, smoother, and more darkly pat- terned than larger shells on open rock surfaces at the same localities. Occasional individuals can be found in which shell shape and sculpture changes abruptly during the course of growth (Figure 11L), supporting the sug- gestion of plasticity. Similarly, examples of sudden color change (Figures 1G, M) imply likely environmental ef- fects on shell coloration. Although abrupt color change has been observed following translocation between mi- crohabitats in Littoraria species (Reid, 1986), there has been no experimental study of phenotypic plasticity in shell color in other littorinids. Among other gastropods, effects of diet upon shell banding patterns have been re- ported in the trochid Austrocochlea (Underwood & Creese, 1976), whereas in neritids this is influenced by cation ratios (Neumann, 1959) and perhaps by salinity (Gundersen & Minton, 1997). Other Taxonomically Useful Characters In addition to their important role in the initial char- acterization of species, anatomical characters may be re- quired to confirm otherwise doubtful identifications. The simple feature of pigmentation of the head can be useful. Although most of the species show either the typical No- dilittorina pattern of head pigmentation, black with a pair of longitudinal black lines on each tentacle, or alterna- tively are entirely black, in N. modesta there are trans- verse black lines on the tentacles. This provides a useful character for its distinction from the other species in the N. modesta group, N. conspersa. Tentacle pattern has also been used as a taxonomic character separating two similar Littorina species, L. scutulata Gould and L. plena Gould (Reid, 1996). As is well known in the Littorindae, penial shape is the most useful of the taxonomic characters and has fre- quently provided the first evidence for the discovery of “sibling’’ species. Since even allopatric sister-species usually show diagnostic penial differences, it has been suggested that penial shape is part of the “‘specific mate recognition system”’ (Paterson, 1985) of Littorina (review by Reid, 1996). Although the descriptions of eastern Pa- cific Nodilittorina species largely support this idea, the differences among members of species complexes are of- Page 156 The Veliger, Vol. 45, No. 2 ten more subtle than those among closely related groups of Littorina (Reid, 1996) or Littoraria (Reid, 1986, 1999a). Consequently, penial shape is sometimes not en- tirely diagnostic as, for example, in the N. porcata and N. aspera species groups (Figures 3, 13, 14). A similar case is known in the sympatric pair Littorina saxatilis (Olivi) and L. arcana Hannaford Ellis, in which penial shape shows some overlap (Hannaford Ellis, 1979), al- though genetic results confirm their species status (review by Reid, 1996). It is likely that the shape of the penis during copulation is different from that in relaxed, fixed specimens (see Bingham, 1972, in Littoraria irrorata (Say)), perhaps aiding species recognition, or alternative- ly other unknown recognition cues may be important in Nodilittorina. As in Littoraria (Reid, 1986), though not in Littorina (Reid, 1996), the paraspermatozoa often show marked differences between Nodilittorina species, even within species groups (e.g., N. aspera group, Figure 15), but the significance of this 1s unknown. Among the Littorinidae as a whole, oviduct structure is Closely tied to the type of spawn and larval develop- ment (Reid, 1989a, 1996). The pallial oviducts of the eastern Pacific Nodilittorina species are mostly rather uni- form, as expected from their similar (whether known or presumed) life histories. Only that of N. fernandezensis is strikingly different from the rest, to which it is probably not closely related (as discussed below). There are small differences between the species groups, but these are not useful for identification within these groups. The egg cap- sules have been described in five of these species; while these are notably different, it remains to be seen whether this will be the case within species groups. Interestingly, the capsule and contained egg are relatively small in the tropical N. dubiosa (capsule 140 wm diameter, ovum 40 zm diameter) and N. atrata (160 wm, 40 wm) from Costa Rica, and larger in N. paytensis in Ecuador (300 ppm, 84 ym) and in Chilean N. araucana (210-256 wm, 68-84 wm) and N. peruviana (336—421 wm, 84—89 wm). These data are limited, but a similar trend of increasing egg and capsule size in colder water has been documented in Lit- torina (Reid, 1996), although there is no convincing ex- planation. Among other gastropods, radulae may provide useful characters for species discrimination, but this is not usu- ally the case among littorinids (e.g., Reid, 1986, 1996), nor is it so among the eastern Pacific Nodilittorina. It has recently been claimed that the radulae of some littorinids show phenotypic plasticity according to the substrate on which they graze (Padilla, 1998; Reid & Mak, 1999). No- dilittorina species are almost always found on rocks so that potential plasticity is not easily studied, but in a sam- ple of N. albicarinata from grasses the radulae did not differ from the normal form. The members of the NV. por- cata group, all of which are relatively small in size, share a similar radular tooth form with pointed cusps, which on the five central teeth in each row are more uniform in size than the elongated major cusps seen in the remaining species. In species of Littorina both juveniles and small adults show relatively pointed cusps; this has been sug- gested to be an allometric effect (Reid, 1996) which might also account for the pattern in small Nodilittorina species. At up to 15 times the length of the shell, the radula of N. aspera is the longest yet reported in this family. Phylogenetic Relationships Although anatomical details are available for all the approximately 60 species of Nodilittorina worldwide, at- tempts at cladistic analysis of morphological characters have so far been uninformative (unpublished observa- tions), a result of relative uniformity in some structures and apparent homoplasy in others. The pallial oviduct is similar in most species (with the exception of the Aus- trolittorina group; there is also some variation in the po- sition of the copulatory bursa), connected with the similar pelagic spawn and planktotrophic development through- out the genus. The radula likewise shows little variation (beyond a trend toward narrowing of the rachidian tooth in some species), which may be related to the high-inter- tidal rock-dwelling habitat of most of these largely trop- ical species. The penis too is rather uniform, with a single mamilliform gland and glandular disc in most species and only subtle interspecific variations in overall shape, while there is likely homoplasy in loss of glandular elements. Shell shape and sculpture, however, are too variable with- in species to provide convenient characters for phyloge- netic analysis. In contrast, in the probable sister-genus Littorina (which occupies a broad latitudinal temperature range, a range of rock and algal substrates, shows a wide diversity of reproductive modes, and much variation in numbers of penial glands) the analysis of anatomical characters has provided a well resolved cladogram, sub- sequently supported by molecular data (Reid, 1989a; Reid et al., 1996; Reid, 1996). As noted earlier (see Remarks on the genus Nodilittorina) it is not even certain that the genus is monophyletic as presently constituted. In Nodi- littorina it is likely that only molecular data will satisfac- torily resolve phylogenetic relationships. Meanwhile, there are some useful groupings based on morphological resemblance rather than formal cladistic analysis. The most obvious of these in the eastern Pacific is per- haps the N. aspera group, in which resemblances are so close that five of the six species have at one time been considered conspecific (see Remarks on N. aspera group). This group shares a spirally sculptured shell without nod- ules, and a striking shell pattern (usually with a more or less developed dark peripheral band), but penis, pallial oviduct, and radula are each of a form common in the genus. Egg capsules have been described only in N. du- biosa and N. paytensis, and show some similarity in the absence or slight development of spiral rings on the cu- D. G. Reid, 2002 pola (compare with figures and references in Reid, 1989a; Mak, 1995; Rudman, 1996). There is a possible parallel in the N. ziczac complex in the western Atlantic, com- prising between five (Reid, 1989a) and seven (Bandel & Kadolsky, 1982) species. These likewise have strongly patterned shells of similar shape and sculpture, but they exhibit a diversity of penial shapes, radulae, and egg cap- sules and so may not be a natural group. It is possible that shell similarities between the N. aspera and N. ziczac complexes are convergent since they are not unique in the genus (e.g., N. punctata (Gmelin), N. peruviana, and some western Pacific species) and there are no apparent anatomical synapomorphies. Since the eastern Pacific and western Atlantic formed a single marine region until the appearance of the Panamanian Isthmus during the Plio- cene, some relationship between their modern faunas is to be expected. Nevertheless, the available evidence gives little indication of this. A second species complex in the eastern Pacific, the N. porcata group, is well defined and probably mono- phyletic, based on the unique or unusual features of the umbilicate shell, strong expression of likely phenotypic plasticity in sculpture, absence of penial glandular disc, twisted tip to the penial filament, flexure in the straight section of pallial oviduct, pointed radular cusps, and sim- ilar mid-shore habitat. The small size, umbilicate shell, and mid-shore or rock pool habitat recalls the pair N. meleagris and N. mespillum in the Atlantic and Carib- bean. Rosewater (1981) introduced the subgenus Fossar- ilittorina for these two species (with N. meleagris as type species) and added WN. atrata, N. porcata, and N. albicar- inata. In this case, a relationship with the Atlantic species is supported by the possible synapomorphies of umbili- cate shell, absence of penial glandular disc, flexure in the oviduct, and radular cusps (although none of these is in- dividually unique, their combination is not found else- where in the genus). Furthermore, paraspermatozoa and egg capsules (known only in N. atrata and N. meleagris; personal observation) are closely similar. The most sig- nificant difference is in the penis which, in the Atlantic species, lacks all glandular projections and has a super- ficially closed sperm duct (Reid, 1989a). The former con- dition is found as a rare abnormality in the eastern Pacific species (N. atrata and N. parcipicta), and the latter is a minor anatomical modification found elsewhere in litto- rinids, so while these characters are likely synapomor- phies of N. meleagris and N. mespillum they do not pre- clude a sister-group relationship with the N. porcata com- plex. The two species of the N. modesta group are undoubted sister-species, sharing almost identical shells, a unique simple and vermiform penis, a unique synapomorphy of projection of the renal oviduct into the spiral of the al- bumen gland, and similar extra denticles on the rachidian tooth. The relationships of this clade are nevertheless ob- scure. As a result of a cladistic analysis of the Littorini- Page 157 dae, Reid (1989a) tentatively placed N. modesta (then considered a single species) together with N. meleagris and N. mespillum in the subgenus Fossarilittorina. How- ever, the only synapomorphy was the absence of mamil- liform penial glands which, as suggested above, is weak and liable to convergence, since mamilliform glands are readily lost (also noted in Littorina, Reid, 1996; and Peasiella, Reid, 1989b). Nodilittorina fernandezensis, endemic to the oceanic islands off Chile, is the only one of the eastern Pacific Nodilittorina species to show a clear relationship with a group of species to the west. As discussed in the Remarks on the species, it is placed in the subgenus Austrolittorina (type species N. unifasciata) together with at least seven species from southern Australia, New Zealand, and South Africa. This subgenus is defined by the synapomorphy of the additional loop of the egg groove through the opaque capsule gland (elsewhere in Nodilittorina shared only with N. pyramidalis, a species of uncertain relationships but possibly belonging to the same clade) and addition- ally characterized by similarities of penial shape and weak shell color pattern. The remaining eastern Pacific Nodilittorina species cannot at present be convincingly linked with other groups within the genus (see Remarks on N. araucana, N. peruviana, and N. galapagiensis). With the exception of Austrolittorina, subgeneric names have not been used here for the tentative groupings suggested. In an earlier review of the genus, Bandel & Kadolsky (1982) remarked on the pervasive homoplasy and likewise did not designate subgeneric groups. In the only formal cladistic analysis, Reid (1989a) accepted three subgenera Fossarilittorina, Echinolittorina, and No- dilittorina. The doubt surrounding the first has been dis- cussed earlier. The latter two were distinguished only by the relative position of the copulatory bursa in the pallial oviduct, but new observations (presented here and un- published) suggest that this distinction is not clear cut. Molecular data are urgently required to address these phylogenetic questions. Distribution Patterns and Faunal Provinces The attempt to define faunal provinces is an unfash- ionable part of marine zoogeography, having been super- seded by studies of regional biodiversity and the phylo- genetic approach to historical biogeography. Neverthe- less, the twin concepts of faunal provinces and the bound- aries between them are heuristically useful, serving as a framework for distributional data, highlighting dispersal processes, and influencing sampling for systematic and genetic studies. Provinces have been defined either by an arbitrary level of endemicity (10% was taken by Briggs, 1974) or by coincidence of many end-points of ranges. However, the distributions of taxonomic groups respond to environmental barriers in different ways, according to Page 158 their biogeographic history, dispersal capabilities, habitat requirements, and physiological tolerances. Therefore, it is not useful to seek a universal classification of marine faunal provinces, except in the broadest terms. The recognition of marine faunal provinces in the east- ern Pacific Ocean has a long and complex history. Since their distributions are relatively well known, studies of mollusks have played an important part (e.g., Carpenter, 1857b; Dall, 1909; Newell, 1948; Olsson, 1961; Valen- tine, 1966; Bernard et al., 1991). There is general agree- ment that the tropical region extends from the Gulf of California south to northernmost Peru, including the oce- anic islands (Islas Revillagigedo, Isla del Coco, Isla de Malpelo, and Galapagos). This has been named the East- ern Pacific Zoogeographic Region (Briggs, 1974), but is now commonly referred to as the Tropical Eastern Pacific or TEP (Hastings, 2000). Although Briggs (1974) clas- sified the Gulf of California (Sea of Cortez) as part of the warm-temperate region to the north, its chief affinities lie with the TEP, and its designation as tropical is not now disputed (Brusca, 1980; Hastings, 2000). The northern limit of the TEP on the Pacific coast of Baja California is set by the influence of the cold southerly California Current. However, this limit is not sharply defined, since this coast is complex, with lagoons and bays providing refugia for tropical species, whereas exposed coasts and upwelling zones harbor a temperate fauna. This is best regarded as a transitional zone between the TEP and warm-temperate Californian Province, lying approximate- ly between Punta Eugenia and Bahia Magdalena (Brusca & Wallerstein, 1979; Brusca, 1980) or extending farther south to Cabo San Lucas (Bernard et al., 1991). The southern limit of the TEP also corresponds to a steep temperature gradient, where the cold northerly Peru (Humboldt) Current sweeps offshore, between the Golfo de Guayaquil and Punta Aguja (3—6°S) (Keen, 1971; Brusca & Wallerstein, 1979; Bernard et al., 1991; Has- tings, 2000). To the south the Peruvian Province (or Peru- Chilean, Briggs, 1974) is of warm-temperate character and extends down the coast of Peru and Chile to merge with the Magellanic Province in a broad transitional zone between 30—46°S (Viviani, 1979; Brattstr6m & Johans- sen, 1983; although Bernard et al., 1991, combined these as a single Chilean Province). The provincial classification of the oceanic islands of the eastern Pacific is problematic, since the faunas are generally impoverished relative to the mainland and are often poorly studied. In addition they may include a pro- portion of rare species that are immigrants from either the Indo-West Pacific or from the mainland, and that do not become established. The classification of the tropical is- lands is discussed below. Of particular interest are the warm-temperate oceanic islands off Chile, the Islas Des- venturadas, and Islas Juan Fernandez. Their molluscan faunas are little known (Odhner, 1922; Rozbaczylo & Castilla, 1987; Bernard et al., 1991), but some species are The Veliger, Vol. 45, No. 2 shared with the Peruvian Province. However, in a list by Rozbaczylo & Castilla (1987) 72% of the 39 recorded mollusks (excluding cephalopods) were given as endem- ic. In a later compilation of the bivalves, 26% of the 31 species from the Juan Fernandez Archipelago were re- corded as endemic, none was shared with the Indo-West Pacific, only three were shared with the still more poorly known Islas Desventuradas, and no endemics were noted on those islands (Bernard et al., 1991). Although these two island groups are only 600 km from the mainland and 800 km apart, the islands appear to be isolated from the continent by the Peru Current flowing northward par- allel to the Chilean coast (Bernard et al., 1991). The sin- gle littorinid found there, N. fernandezensis, is endemic and appears to be conspecific on the two island groups. As noted earlier, its relationships are undoubtedly with a southern-temperate group from Australia, New Zealand, and South Africa (subgenus Austrolittorina). Similar trans-Pacific relationships of mollusks at subtropical and warm-temperate latitudes (for example, of Islas Juan Fer- nandez and Isla de Pascua with Australia and New Zea- land) have been noted before (Rehder, 1980; Lindberg & Hickman, 1986: Bernard et al., 1991). The distances are too great for transport of pelagic larvae (except teleplanic forms) in oceanic currents, but rafting of adults has been suggested for a trans-Pacific oyster (O Foighil et al., 1999). Alternatively, trans-Pacific dispersal of shallow- water species may have been facilitated by the presence of little-known or uncharted reefs in these latitudes in the South Pacific Ocean; at times of low sea level these may have emerged as islands to act as stepping stones for lit- toral species (P. Bouchet, personal communication). In a recent list of 51 fishes of the Juan Fernandez Islands, Pequeno & Saez (2000) found that 25.5% were endemic, 29.4% shared only with the Islas Desventuradas, and that slightly more species were shared with Pacific islands to the west than with the mainland to the east (19.6% com- pared with 15.6%). It seems appropriate that the Islas Juan Fernandez and Desventuradas should together be in- cluded in a distinct Juan Fernandez Province, as proposed by Briggs (1974), although whether this is classified as part of the warm-temperate region of the South American mainland (Briggs, 1974) or of the tropical Indo-West Pa- cific region (Pequefio & Saez, 2000) is debated. Opinions about the subdivision of the TEP region into smaller faunal provinces are diverse and dependent upon the group studied. Molluscan workers have, with few ex- ceptions, emphasized the faunal uniformity of the TEP (named the ‘‘Panamic Province”’ in molluscan texts) and have not identified distributional boundaries within it (Dall, 1909; Keen, 1958, 1971; Olsson, 1961; Bernard et al., 1991; Emerson & Chaney, 1995; Roy et al., 1998). This is so even when considering the molluscan fauna of the Galapagos Islands with endemicity estimated as 18— 23% (Finet, 1991; Kay, 1991). However, Keen (1958) remarked on Panamic ‘“‘subprovinces” in the northern D. G. Reid, 2002 Page 159 Gulf of California and Gulf of Panama, and Vermeij (1991) suggested that the Mexican coast and Gulf of Cal- ifornia have acted as refuges from extinction for mollusks that were formerly more widespread within the TEP. Working with echinoderms, Maluf (1988) found high overall faunal similarity within the TEP from Cabo San Lucas to Peru, but recognized the Gulf of California (Cor- tez Province) as distinct (based on species shared with the Californian Province, and despite low endemicity of only 2%) and also the Galapagos Province (endemicity 16%). Using decapods, Correa-Sandoval & Rodriguez- Cortés (1998) accepted a Cortez Province with 24% en- demicity, distinct from Mexican and Panamic Provinces to the south, contrary to an earlier study in which Cortez and Mexican Provinces were united (Hendrickx, 1992). Based on analysis of the depauperate zooxanthellate coral fauna of the TEP, Glynn & Ault (2000) found similarities among the Islas Revillagigedo, Gulf of California, and southern Mexico, suggesting a provincial difference from the group of southern localities (Central America, Ecua- dor, Galapagos). However, it has been studies of shore fishes that have led to the clearest subdivision of the TEP. Although with differences of detail, most workers have divided the region into four provinces: Cortez, Mexican, Panamic, and Galapagos (Hubbs, 1952; Briggs, 1955, 1974; Springer, 1958; Walker, 1960; Hastings, 2000), sep- arated mainly by gaps of open ocean and of inhospitable coastline without rocky substrates. The limits of these provinces can be defined as follows (where authors dis- agree, the boundaries have been selected for maximum agreement with the distributions of Nodilittorina reported here; see Figure 23). The Cortez Province includes the entire Gulf of California as far south as La Paz on the eastern coast of Baja California (Hubbs, 1952; Briggs, 1974) and Topolobampo (Sinaloa) on the mainland (Briggs, 1974; Hastings, 2000). The northern boundary of the Mexican Province is disputed; Hastings (2000) re- stricted this province to the mainland south of Mazatlan, while extending the Cortez Province around the tip of Baja California to the junction with the Californian Prov- ince. Here, however, the southwestern coast of Baja Cal- ifornia (Punta Eugenia to La Paz) is included with the Mexican mainland south of Mazatlan (Hubbs, 1952; Springer, 1958; Walker, 1960; Briggs, 1974). The south- ern limit of the Mexican Province is near Salina Cruz in the Golfo de Tehuantepec (Southern Mexico) (Briggs, 1955, 1974; Springer, 1958; Hastings, 2000). Here, the Islas Revillagigedo are classified in the Mexican Prov- ince, although included in the Panamic Province by Briggs (1974). The Panamic Province (Panamanian of Briggs, 1974) is restricted to the region south of the Golfo de Fonseca (between El Salvador and Nicaragua) (Spring- er, 1958; Hastings, 2000) and includes Isla del Coco (Co- cos Island) and Isla de Malpelo. The distributions of Nodilittorina species and, for com- parison, of Littoraria species (from Reid, 1999a) are sum- marized in Table 4. There is a close correspondence with the faunal provinces as defined on the basis of shore fish- es. Of the 18 species of Nodilittorina, only four extend their distributions (with apparently self-sustaining popu- lations) through large parts of two adjacent provinces (N. atrata and N. conspersa in Panamic and Galapagos; N. albicarinata in Cortez and Mexican; N. apicina in Mex- ican and Panamic). For these littorinids, the barriers be- tween the provinces are evidently remarkably effective. Oceanographic conditions clearly play some part. The steep temperature gradients at the northern and southern boundaries of the TEP have been mentioned, but temper- ature limitation is probably not significant within the TEP where temperatures exceed 20—25°C throughout the year (Bernard et al., 1991; Correa-Sandoval & Rodriguez-Cor- tés, 1998). During El Nino events the latitudinal extent of the TEP widens, which may account for occasional records of Panamic mollusks beyond their normal limits in northern Peru (Paredes et al., 1998). The Galapagos Islands are isolated from the mainland of Ecuador by 1000 km of open ocean, although under the influence of the Peruvian Current and of the Panama Current (from January to April) (Finet, 1991). Within the TEP the major currents are the northward Costa Rica Current (stronger in the summer, when it reaches the Gulf of California), the Panama Bight Gyre and the Panama Current (Bernard et al., 1991; Correa-Sandoval & Rodriguez-Cortés, 1998; Glynn & Ault, 2000) but, while significant for dispersal, these are not obviously connected with provincial bound- aries. The influence of oceanographic conditions related to productivity, upwelling, and freshwater inflow are not understood. The distinction between “‘oceanic”’ and “continental” distributions among littorinids and other mollusks has often been noted (Reid, 1986, 1989b, 1999a) and may in some way be connected with the high productivity, turbidity, and runoff on continental margins. It may therefore be significant that the Panamic Province includes three areas of upwelling (in the Gulfs of Te- huantepec, Papagayo, and Panama) and has by far the highest freshwater input in the TEP, resulting in high algal productivity and turbidity (Glynn & Ault, 2000; Oceanic Primary Productivity Study, Rutgers University), thus providing a typically “‘continental” habitat for shallow- water mollusks. The Gulf of California is also an area of high oceanic productivity, whereas the Pacific coast of Baja California and most of the Mexican Province (with the exception of a periodic -upwelling off the coast of Jalisco) provide typically “‘oceanic’’ conditions of low productivity and clear water (Santamaria-del-Angel et al., 1994; Barnard et al., 1999; Glynn & Ault, 2000; Oceanic Primary Productivity Study, Rutgers University). How- ever, by far the most important determinant of provincial boundaries along the contiguous TEP coastline appears to be simply the availability of suitable intertidal habitat. As recognized by workers on shore fishes that, like Nodilittorina species, require rocky substrate, the Cortez Page 160 The Veliger, Vol. 45, No. 120° 110° 100° 69 oe a 40° 30° Cortez i Province 20° i Revillagigedo Mexican Province : 10° Clipperton Atoll P ute Province Isla del Coco Coen Colombian Isla de Malpelo ~ San Lorenzo 0° san : Galapagos Province 10° a 120° 110° 100° 90° a it Figure 23. Faunal provinces of the Tropical Eastern Pacific Region (TEP), based on distribution of shallow-water fauna of rocky substrates, principally fish and Nodilittorina species (modified from Springer, 1958; Briggs, 1974; Hastings, 2000). Cross-hatched areas are transitional zones between TEP and (to the north) the Californian Province and (to the south) the Peruvian Province. D. G. Reid, 2002 Page 161 Table 4 Distributional ranges of Littorinidae (Nodilittorina and, from Reid, 1999, Littoraria) from Baja California to Chile, listed by marine faunal provinces (Figure 23; see text for definitions). For Nodilittorina, “species groups” are tentatively suggested as possible monophyletic groups, based on likely synapomorphies and overall similarity. Species are listed in the provinces in which they have all or a significant part (1.e., likely self-sustaining populations) of their distributions. Occasional rare records are indicated by +. Califor- Species groups nian Cortez Mexican Panamic Galapagos Peruvian Juan Fernandez N. atrata N. atrata N. atrata N. porcata N. porcata N. santelenae N. santelenae N. fuscolineata N. fuscolineata N. parcipicta aly N. parcipicta N. albicarinata + N. albicarinata N. albicarinata N. modesta ats N. modesta + N. conspersa + N. conspersa N. conspersa N. aspera AP N. aspera + N. tenuistriata N. tenuistriata N. dubiosa N. dubiosa ate N. apicina ar N. apicina N. apicina N. penicillata N. penicillata ar N. paytensis N. paytensis + N. araucana N. araucana N. peruviana N. peruviana N. galapagiensis N. galapagiensis N. fernandezensis N. fernandezensis L. pintado pullata L. pintado L. pintado pullata pullata L. varia L. varia L. zebra L. zebra L. variegata L. variegata L. variegata L. variegata L. rosewateri L. rosewateri L. rosewateri L. rosewateri L. aberrans L. aberrans and Mexican Provinces are separated by a stretch of pre- dominantly muddy coastline with mangroves and deltas that extends for 700 km from Guaymas to Mazatlan (Briggs, 1955, 1974; Springer, 1958). An isolated rock outcrop occurs at Topolobampo (Sinaloa), and this is now taken as the southern limit of the Cortez Province for shore fishes, separated from the Mexican Province by the “Sinaloan Gap” of 370 km (Hastings, 2000; Figure 23). A similar barrier, the Central American Gap, separates the Mexican and Panamic Provinces, consisting of over 1200 km of sand, mud, and mangrove lagoons between the Golfo de Tehuantepec and the Golfo de Fonseca (Spring- er, 1958; Briggs, 1974; Hastings, 2000; Figure 23). Likely stepping stones are found in El Salvador at Los Cobanos and La Libertad, where, respectively, N. atrata and N. apicina have been found (see also Glynn & Ault, 2000). The boundary between the Cortez and Mexican Provinces in the vicinity of La Paz, Baja California, cannot be ex- plained so easily. Rocky shores are more or less contin- uous, but perhaps the greater wave exposure and lower oceanic productivity in southeastern Baja California are significant; these conditions are more similar to the main- land coast of the Mexican Province than to the Gulf of California. Those Nodilittorina species restricted to the Mexican Province are characteristic of wave-exposed coasts (N. parcipicta, N. modesta, N. aspera) and those of the Cortez Province of sheltered shores (N. albicari- nata) or a range of exposure (N. penicillata). In addition to the Sinaloan and Central American Gaps, there is another large expanse of sedimentary shore and mangroves, extending more than 500 km between Cabo Corrientes (Colombia) and San Lorenzo (Ecuador). The biogeographic implications do not appear to have been mentioned previously and the area can be termed the Col- ombian Gap (Figure 23). There is some evidence from the distributions of Nodilittorina species that this gap also presents a barrier to dispersal. Of the six species occur- ring commonly in the Panamic Province north of this gap, Page 162 The Veliger, Vol. 45, No. 2 only four are also common south of it in Ecuador (N. atrata, N. conspersa, N. tenuistriata, N. apicina). Of the other two, N. fuscolineata is likely a chance immigrant in Ecuador, whereas N. dubiosa has not been recorded south of Isla Gorgona, which is a stepping stone of rocky shore within the gap. Conversely, N. santelenae is en- demic to Ecuador and northern Peru. The status of WN. paytensis is uncertain; it is abundant in Ecuador and northern Peru, but there are only three records from Co- lombia and Costa Rica, only one of which was of a large population; it may therefore be another species virtually endemic to the tropical region south of the Colombian Gap. This gap is evidently a less effective barrier for lit- torinids than the two farther north, perhaps owing to the presence of stepping stones, but is still significant for some. These data as yet provide little evidence upon which to subdivide the Panamic Province, although the possibility should be considered when the poorly known Ecuadorean fauna is studied. It should also be noted that as natural coastlines are altered by clearing of mangroves and building of marine structures to act as artificial step- ping stones, these three gaps in the tocky-shore fauna of the TEP may become less effective, permitting permanent range extensions into adjacent provinces (Glynn & Ault, 2000). While the correspondence between littorinid distribu- tions and the provinces of the TEP is striking, the habitat and water gaps delimiting the provinces clearly do not present impassable barriers. In fact there are eight known cases of species that are recorded as rare arrivals in ad- jacent provinces (Table 4; not including two extensions into the temperate Californian and Peruvian Provinces). The dispersal capabilities of tropical littorinids are not known in detail. Only a single species, N. hawaiiensis, has been successfully reared in the laboratory, taking on average 24 days from spawning to metamorphosis at 25°C (Struhsaker & Costlow, 1968, as “‘Littorina picta”’). From similarities in oviduct structure and protoconch through- out the genus, planktotrophic development in the Nodi- littorina species of the TEP is predicted to be similar to that of this Indo-Pacific species. At this rate of develop- ment, a moderate current speed of only 40 km per day would be sufficient to transport pelagic eggs and larvae for 1000 km. Therefore it is not remarkable that mainland species reach the Galapagos Islands, or that species can span the Central American Gap. More surprising is that these barriers are so effective and that immigrants do not become established. While environmental conditions or competitive effects might be invoked, it should also be noted that establishment of self-sustaining populations of planktotrophic-developing species at a large distance from the source population is difficult, since pelagic eggs and larvae are swept away from founding individuals and settle only at very low density (Johannesson, 1988). Thus wide habitat gaps may indeed be effective barriers to col- onization, although not to occasional immigration. In as- sessing the causes of provinciality within the TEP, it is interesting to compare the distributions of Nodilittorina with those of the only other native littorinid genus, Lit- toraria (Table 4; Reid, 1999a). Of the six endemic Lit- toraria species, only one (L. pintado pullata (Carpenter)) occurs on rocky shores and this is restricted to the Mex- ican Province (the southern tip of Baja California and Mexican mainland), but also including Clipperton Atoll (at the boundary between the Indo-West Pacific and TEP) and Isla del Coco (classified as part of the Panamic Prov- ince). However, the five remaining species inhabit man- grove trees and (in some cases) salt marsh vegetation. Of these five, three are strictly Panamic, whereas two (L. variegata (Souleyet) and L. rosewateri) extend the length of the TEP from the Gulf of California to Peru. These species are more widespread than any of the rocky-shore Nodilittorina species, perhaps because the mangrove hab- itat is More continuous (and provides more opportunities for dispersal by rafting). For these mangrove-associated species the significant barrier is the expanse of rocky shore without open-coast mangrove habitats (Glynn & Ault, 2000) along almost the entire mainland coast of the Mexican Province (Reid, 1999a). Significant barriers to dispersal, and hence the designation of “provincial boundaries,’ can therefore differ among ecological (and taxonomic) groups of animals. To the west of the TEP lies the great expanse (at least 5400 km) of open ocean that constitutes the Eastern Pa- cific Barrier, the most effective oceanic barrier to the dis- persal of shallow-water fauna in the world’s oceans (Grigg & Hey, 1992). Even this barrier is not imperme- able to animals with sufficiently long pelagic stages and it acts as a largely unidirectional (west to east) filter bridge (Glynn & Ault, 2000). Recently, three littorinid species from the Indo-West Pacific (TWP) Province have been recorded from the TEP for the first time, from Clip- perton Atoll, Isla del Coco, and Costa Rica (Reid & Kai- ser, 2001). So far, no trans-Pacific Nodilittorina species have been found in the TEP. The most isolated of the oceanic islands in the TEP is Clipperton Atoll, with the highest representation of TWP fauna in the TEP (Emer- son, 1991; Robertson & Allen, 1996; Glynn & Ault, 2000). Of the TEP Nodilittorina species only N. modesta is found at Clipperton Atoll, where it is an occasional immigrant. This review of provinciality in the rocky-shore fauna of the TEP holds potentially important implications for systematic malacology in the region. The prevailing con- cept in the malacological literature of a uniform ‘‘Pan- amic Province’’ from the Gulf of California to northern Peru (i.e., equivalent to the TEP region) is based largely on two influential studies of bivalves (Olsson, 1961; Ber- nard et al., 1991). Since bivalves are predominantly a subtidal, soft-bottom group, this may explain why the provinciality of the TEP has not been more widely no- ticed previously. As revisionary work progresses on the D. G. Reid, 2002 shallow-water gastropods of hard substrates, it is likely that genera in addition to Nodilittorina will show a more marked provincial diversity than is currently recognized. Already Vermeij (2001) has indicated examples in the genera Neorapana, Stramonita, and Nerita. Even in some infaunal bivalve genera, careful systematic work has re- vealed provincial endemics as well as genuinely wide- spread species (Coan, 1983; Roopnarine, 1996). In future, when sampling supposedly widespread species from the TEP for systematic and genetic purposes, samples should be included from the four TEP provinces described here (Figure 23) and long known in other animal groups. Historical Biogeography and Speciation In the absence of both a rigorous phylogenetic hypoth- esis and a fossil record, discussion of historical bioge- ography and patterns of speciation can only be specula- tive. The Pliocene history of Central America is domi- nated by the uplift and (at 3.1—2.8 Ma) final closure of the Isthmus of Panama (Coates & Obando, 1996). This vicariant event separated the biota of the TEP and tropical western Atlantic and had profound evolutionary conse- quences, being followed by a marked impoverishment of the tropical American marine fauna. The causes and tim- ing of the extinctions are still debated, but they had a more pronounced effect in the Caribbean. As a result, during the later Pliocene many of the taxa formerly wide- spread in tropical America became restricted to the Pa- cific side of the isthmus, far outnumbering those that sur- vived only on the Atlantic side (Vermeij & Petuch, 1986; Vermeij, 1991, 1993). Nevertheless, overall molluscan di- versity has remained comparable in both oceans, perhaps because extinction in the western Atlantic was balanced by speciation and immigration (Allmon et al., 1993, 1996; Jackson et al., 1993). However, when inter-oceanic com- parisons have been made within single molluscan clades with a good fossil record, they have revealed both higher extinction in the western Atlantic and higher diversifica- tion in the TEP, resulting in the modern higher diversity of the latter (e.g., chionine Veneridae, Roopnarine, 1996; Strombina, Jackson et al., 1996; Thais-like muricids and others, Vermeij, 2001). Among littorinids, there is evi- dence of higher modern diversity in the TEP than in the western Atlantic within a clade of mangrove-associated members of Littoraria, but in the absence of a fossil re- cord this cannot yet be ascribed to differential diversifi- cation or extinction (Reid, 1999a). Against this background, the perceived higher diversity of the genus Nodilittorina in the Caribbean than in the TEP under previous classifications of the group was sur- prising. The most recent listing (Reid, 1989a) gave five species in the TEP (N. porcata, N. albicarinata, N. mo- desta, N. aspera, N. galapagiensis) and eight (N. melea- gris, N. mespillum, N. angustior (Merch), N. dilatata, N. interrupta, N. riisei, N. tuberculata, N. ziczac) in the Ca- Page 163 ribbean. The revision of Nodilittorina species in the TEP shows that this is not in fact the case, the recognized total for the entire TEP region being 15 species (Table 4). De- spite the relatively recent separation of the TEP and Ca- ribbean faunas, the possible phylogenetic relationships between Nodilittorina species on either side of the Isth- mus remain obscure. As suggested earlier, the N. porcata group may perhaps be a sister-radiation to the Caribbean pair, N. meleagris and N. mespillum, and the N. aspera group shows some similarity to the N. ziczac group in the Caribbean. Nevertheless, the lack of clear trans-isthmian relationships implies that significant diversification and/ or extinction in the two regions has taken place since their separation. Preliminary studies of the distributions of sister-species pairs in Littorinidae suggest that the prevailing mode of speciation has been allopatric (Reid, 1994, 1996). The distributional data for Nodilittorina in the eastern Pacific support this conclusion, since species pairs and triplets that are likely most closely related are largely allopatric (Table 4). Whether speciation in these cases has proceed- ed by vicariance of an originally more extensive range by imposition of a barrier to gene flow, or by dispersal across a pre-existing barrier (founder or peripatric spe- ciation) cannot yet be ascertained (except in the case of Galapagos and Juan Fernandez endemics, for which only founder speciation is possible). If, as argued earlier, hab- itat gaps are the main determinants of range limits for these species in the TEP, then knowledge of the age of the coastal landforms will be important. The observation that dispersal across these barriers is relatively frequent might suggest that founder events have played a part. This diverse group of rocky-shore gastropods, with precisely known geographical distributions, could provide a model system for the study of speciation in the TEP. First, however, a robust phylogenetic hypothesis is re- quired and, for this, molecular data are now being sought. Acknowledgments. Field work in Costa Rica was undertaken during the tenure of a postdoctoral fellowship at the National Museum of Natural History, Smithsonian Institution. In Costa Rica I thank the Consejo Nacional de Investigaciones Cientificas y Technologicas for permission to use the Laboratorio de Inves- tigaciones Marinas at Punta Morales, the Organization for Trop- ical Studies for transport, and W. A. Szelistowski for assistance in the field. I am most grateful to S. A. Jeffcoat for help during field work in Mexico. Collections in southern Chile were made during an expedition jointly organized by The Natural History Museum and Raleigh International, funded by the British Gov- ernment’s Darwin Initiative for the Survival of Species. Field- work in Ecuador was assisted by a grant from the Percy Sladen Memorial Fund of the Linnean Society of London. In Ecuador a field trip was kindly arranged by M. Cruz and E. Mora, assisted by A. Calles, M. EF Arroyo, and D. Merino. 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C. 1892. Preliminary description of new mollus- can forms from west American regions, etc. The Nautilus 6: 85-89. STEARNS, R. E. C. 1893a. On rare or little known mollusks from the west coast of North and South America, with descrip- tions of new species. Proceedings of the United States Na- tional Museum 16:341-—352. STEARNS, R. E. C. 1893b. Scientific results of explorations by the U.S. Fish Commission steamer Albatross. No. XX V.—Re- port’on the mollusk-fauna of the Galapagos Islands, with descriptions of new species. Proceedings of the United States National Museum 16:353—450. STREBEL, H. 1907. Beitraige zur Kenntnis der Molluskenfauna der Magalhaen-Provinz. No. 5. Zoologische Jahrbiicher. Abtei- lung fiir Systematik, Geographie und Biologie der Tiere 25: 79-196. STRUHSAKER, J. W. 1968. Selection mechanisms associated with intraspecific shell variation in Littorina picta (Prosobran- chia: Mesogastropoda). Evolution 22:459—480. STRUHSAKER, J. W. & J. D. CostLow. 1968. 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Marine Biology 129:331— 342. Woop, W. 1828. Supplement to the Index Testaceologicus; or a Catalogue of Shells, British and Foreign. London. iv + 59 pp. The Veliger 45(2):171—174 (April 1, 2002) THE VELIGER © CMS, Inc., 2002 NOTES, INFORMATION & NEWS A Useful Marker for the Study of Neural Development in Cephalopods Shuichi Shigeno and Masamichi Yamamoto Ushimado Marine Laboratory, Okayama University, Ushimado, Okayama, 701-4303 Japan In cephalopods, there is no suitable marker that visualizes three-dimensional neural patterns in the preserved embry- os. Development of the nervous system has been studied using conventional histological techniques (Meister, 1972; Marquis, 1989). Silver impregnation and methylene blue staining have been used in anatomical studies of the nervous system in cephalopods (Stephens, 1971) but the former are applicable only to late embryonic stages (Mar- tin, 1977) and the latter, only to living neurons. Cobalt backfilling (Budelmann & Young, 1987) and Dil injection (Robertson et al., 1993) only label local neuronal patterns. We tried whole mount immunostaining of cephalopod embryos and hatchlings with commercially obtainable monoclonal antibodies and found acetylated a-tubulin a suitable immunohistochemical marker to visualize the overall pattern of developing neurons. We used four sepiids, /diosepius paradoxus Ortmann, 1881; Euprymna morsei (Verrill, 1881); Sepia lycidas Gray, 1849; Sepiella japonica Sasaki, 1929; two teu- thoids, Loliolus japonica, Hoyle, 1885; Todarodes paci- ficus Steenstrup, 1880; and an octopod, Octopus ocellatus Figure 1. Neuropiles in whole-mount of specimens immuno- stained with acetylated a-tubulin antibody. A. The vertical lobe (vn) and the superior buccal lobe (sb) in a late embryo of Sepia lycidas. The cranial cartilage is removed. Scale bar = 300 pm. B. The stellate ganglion (stg) and the posterior subesophageal mass (pms) in an Idiosepius paradoxus hatchling. Scale bar = 30 pm. Gray, 1849 (Octopoda). Dechorionated embryos at vari- ous stages of neurogenesis and hatchlings were fixed in 4% paraformaldehyde (PFA) dissolved in phosphate buff- ered saline (pH 7.6) (PBS) for 12—24 hr at 4°C. Samples were washed with PBS, dehydrated in a methanol series, and stored in 80% methanol at —20°C. Some samples were also fixed in Bouin’s solution/seawater, dehydrated with an ethanol series, and stored in 70% ethanol at room temperature. The stored samples to be immunostained were placed as a whole, or after dissection into a few pieces, in ice-cold 50% dimethyl sulfoxide (DMSO)/ methanol with 10% hydrogen peroxide for 5 min. They were incubated for 30 min at 4°C in the DMSO solution with 1% Triton X-100, washed with Tris-buffered saline (TST; 20 mM Tris-HCl, pH 8.0, 150mM NaCl, 0.1% Tri- ton X-100) containing 5% DMSO, and blocked with 5% non-fat dry milk (TSTM) overnight at 4°C. The speci- mens were incubated with anti-acetylated a-tubulin anti- body (Sigma) diluted 1:750—1000 in TSTM for 2—4 d at 4°C (Gianni & Fuller, 1985). After being washed with TSTM, some samples were incubated in pre-diluted goat anti-mouse antibody conjugated to peroxidase (Envi- sion+, DAKO) for 12—24 hr at room temperature, washed with TSTM, immersed in ice-cold 3,3’-diaminobenzidine (DAB) (1 mg/ml TST) for 1 hr, and reacted by adding hydrogen peroxide (0.01%) for 5—20 min in the dark. The other samples were stained with ABC high-HRP immu- nostaining kit (TOYOBO) according to the standard pro- tocol. Anti-acetylated a-tubulin clearly stained peripheral nerve fibers as well as neuropiles in the brain (Figure 1A). It also stained the epidermal cilia, lateral lines, ec- todermal photosensitive vesicles, Kélliker’s canals of the statocysts, and olfactory organs. The antibody recognized neurons even in Bouin-fixed specimens that had been stored for 3 yr in ethanol, though not always consistently. As for the secondary antibodies, Envision+ (DAKO) was slightly more effective than ABC high HRP (TOYOBO) kit. The intensity and the extent of visualization depended on the limit of penetration of the antibodies. In small specimens, such as the embryos and hatchlings of J. par- adoxus and the embryos of E. morsei, all neuronal ele- ments, i.e., peripheral nerves and neuropiles in the brain, were observable in the samples mounted as a whole (Fig- ure 1B). In larger specimens, such as O. ocellatus, S. lycidas, S. japonica, and L. japonica, dissection was nec- essary before immunostaining permitted visualization of the neuropiles in the deep portion of the brain and all the peripheral nerve fibers in the body. We tested two other monoclonal antibodies, anti-neurofilament 200 (Sigma) Page 172 and anti-HRP (Sigma) (Jan & Jan 1982), but they did not recognize any neuronal elements. Acknowledgments. We thank Mr. W. Godo and Dr. T. Akiyama for their help in collecting cephalopods, and Ms. M. Yoshioka, Dr. S. Segawa, Dr. K. Fujita, and Mr. K. Kidokoro for supplying some cephalopod samples. Thanks are also due to Dr. Sv. Bol- etzky for his kind help in preparing the manuscript. Literature Cited BUDELMANN, B. U. & J. Z. YOUNG. 1987. Brain pathways of the brachial nerves of Sepia and Loligo. Philosophical Trans- actions of Royal Society of London Series B, 315:345—352. GIANNI, P. & M. T. FULLER. 1985. Monoclonal antibodies specific for an acetylated form of a-tubulin recognize the antigen in cilia and flagella from a variety of organisms. Journal of Cell Biology 101:2085—2094. JAN, L. Y. & Y. H. JAN. 1982. Antibodies to horseradish perox- idase as specific neuronal markers in Drosophila and in grasshopper embryos. Proceedings of the National Academy of Science of the United States of America 79:2700—2704. Margulis, E 1989. Die Embryonalentwicklung des Nervensys- tems von Octopus vulgaris Lam. (Cephalopoda, Octopoda), eine histologische Analyse. Verhandlungen der Naturfor- schenden Gesellschaft in Basel 99:23-75. Martin, R. 1977. The giant nerve fiber system of cephalopods, recent structural findings. Symposia of the Zoological So- ciety of London 38:261—275. MEISTER, G. 1972. Organogenese von Loligo vulgaris Lam (Mol- lusca, Cephalopoda, Teuthoidea, Myopsida, Loliginidae). Zoologische Jahrbiicher—Abteilung fiir Anatomie unt On- togenie der Tiere 89:247—300. ROBERTSON, J. D., G. M. SCHWARTZ & P. LEE. 1993. Carbocy- anine dye labeling reveals a new motor nucleus in Octopus brain. Journal of Comparative Neurology 328:485—500. STEPHENS, P. R. 1971. Histological methods. Pp. 646-649 in J. Z. YOUNG (ed.), The Anatomy of the Nervous System of Octopus vulgaris. Clarendon Press: Crepidula dilatata Lamarck, 1822, Truly Living in the Southwestern Atlantic Pablo E. Penchaszadeh,! Guido Pastorino,* and Maximiliano Cled6n? ' RCEyN—UBA—CONICET, Museo Argentino de Ciencias Naturales, Av. Angel Gallardo 470 3° piso lab 57, C1405DJR Buenos Aires, Argentina; e-mail: pablop@mail.retina.ar > CONICET, Museo Argentino de Ciencias Naturales, Av. Angel Gallardo 470 3° piso lab 57, C1405DJR Buenos Aires, Argentina; e-mail: rvpastor@criba.edu.ar * FCEyN—UBA, Museo Argentino de Ciencias Naturales, Av. Angel Gallardo 470 3° piso lab 57, C1405DJR Buenos Aires, Argentina Crepidula fecunda Gallardo, 1979, was described from Bahia Chinquihue (41°31'S—73°03'W) in the Chilean Pa- The Veliger, Vol. 45, No. 2 cific. The distribution ranges from the type locality, 41°S, to 45°S off the Chilean coast. According to Gal- lardo (1979), C. dilatata Lamarck, 1822, can only be differentiated by its direct development and the presence of embryos consuming nurse eggs. Adult morphological features are identical. Therefore, earlier records refer- ring to the presence of C. dilatata in the Atlantic coast of South America (Parodiz, 1939) need validation. The type locality of C. dilatata remains unknown. Mermod (1950) mentioned in a commented list of the types from Lamarck’s collection, the Western coast of South Amer- ica as a probable type locality. Gallardo (1979) recorded C. dilatata Lamarck, from 21°11'S to 43°47'S. He also stated (in Spanish in the original): “It is probable that future studies including developmental stages, will ex- pand this distribution particularly towards the Argentine Atlantic coast.” This note confirms the presence of C. dilatata (Figures 1-9) in Argentine waters and restricts C. fecunda to Chile. Egg capsules and adult males and females were col- lected from Bahia Ensenada, Ushuaia (~55°S) by SCU- BA diving in 3—4 m depth, attached to the root of the common kelp Macrocystis pyrifera (Linnaeus); Punta Penas, Puerto San Julidn (49°15'S—67°39'W) in 2 m depth; and Punta Dos Hermanas, Puerto Deseado (47°10'S; 2-3 m depth) in Santa Cruz province; and sev- eral localities around Golfo Nuevo (~42°30'S) in Chubut province (subtidal). All collections were made during February 2000. We studied more than 100 brooding females (vouch- er material was deposited in Museo Argentino de Cien- cias Naturales, number MACN 33901). Most females were brooding egg masses at advanced stages of em- bryonic development, containing embryos and un- cleaved nurse eggs or crawling juveniles. This fact con- firms the presence of C. dilatata in the southern Atlan- tic, and as far as we observed, restricts C. fecunda to the Pacific. The observed material was completely homogeneous, with only one developmental mode characterized by the presence of nurse eggs. Each egg capsule (n = 150) con- tained 203-375 eggs (mean = 303, SD = 54) with only two to 12 developing embryos, representing as an average 2.4% of the initial egg number. The average uncleaved egg diameter was 214 wm (SD = 13 wm, n = 72). The egg diameter distribution adjusted to a normal distribution with a single mode was 212 wm. Hatching occurred at a crawling juvenile stage. The egg capsule size averaged 3873 wm in length and 3954 pm in width (SD = 648 and 527 wm, respectively). Brooding females measured 11— 32 mm (mean = 22 mm) in shell length, but in this pro- tandric species the loss of penis can be already observed at 11 mm of shell length. Males (with a penis) measured 7-19 mm of shell length. The Argentine material agrees with Gallardo’s (1976, Notes, Information & News Page 173 Figures 1-9. Crepidula dilatata. Figure 1. Internal view of a female shell; scale bar = 1 cm. Figure 2. Dorsal view of the same specimen with a male shell in stacking position. Figure 3. Internal view of the male specimen from Figure 2. Figure 4. Egg capsule removed from a just laid egg mass; scale bar under 5. Figure 5. Egg capsule with embryos and remaining nurse eggs; scale bar = 2 mm. Figure 6. Egg capsule just prior to hatching with no remaining nurse eggs; scale bar under 5. Figure 7. SEM detail of the ornamentation of the embryonic shell in Figure 8; scale bar = 50 mm. Figure 8. SEM, apertural view of the larval shell; scale bar = 0.5 mm. Figure 9. SEM, dorsal view of the embryonic shell; scale bar = 0.5 mm. Page 174 The Veliger, Vol: 455 Noy Table | Comparison of reproduction of Argentine and Chilean specimens of Crepidula dilatata Lamarck, 1822. Egg capsules Eggs per Embryos per Egg diameter Crawling juvenile Male shell Female shell Source per egg mass egg capsule egg capsule (ym) length (4m) length (um) length (wm) Gallardo, 1979 22-29 308-1016 15-18 195-263 900-1300 6—26 12-53 Chaparro & Paschke, 1990 = — — = 1075-1600 — _ Present study 9-22 203-375 2-12 197-263 740—1600 7-19.11 11-32 Table 2 Regression and correlation analysis of eggs and egg capsules of Crepidula dilatata Lamarck, 1822. iP F m P Egg capsule length-number of eggs per egg capsule (n = 150) 0.33 WPS) 0.05 0.05 Number of egg capsules per egg mass—egg capsule length (n = 30) 0.14 4.39 54.8 0.05 Number of egg capsules per egg mass—number of eggs per egg capsule (n = 30) 0.07 eS 35)// 0.05 Egg capsule length-egg capsule width (n = 150) 0.24 8.63 0.4 0.05 1977, 1979) and Gallardo & Garrido’s (1987) general de- scription of the reproduction of C. dilatata. We noted, however, some differences. The maximum adult shell length was lower in the Argentine samples than those from Chile (Table 1). This fact could account for the fewer egg capsules per brood found in the Argentinean material (Ta- ble 1). There were also fewer developing embryos per egg capsule in the Atlantic sample compared with those studied by Gallardo (1979). The uncleaved egg diameter was be- tween 197 and 263 pm, similar for the Chilean population (Table 1), but we never found two different groups of egg diameters as suggested by Gallardo (1976, 1979). Further studies with a greater number of animals from both sides of the continent would clarify this matter. There is a linear relationship between the number of egg capsules per brood and the number of eggs. When the egg mass has more egg capsules, each egg capsule is larger and contains more eggs (Table 2). The number of eggs per capsule, the presence of nurse eggs, the hatching shell size, and the hatching stage as crawling juveniles agree with C. dilatata’s reproductive pattern as described by Gallardo (1979) and Chaparro & Paschke (1990). We therefore consider the presence of C. dilatata along the Argentine coast to be truly demonstrat- ed. As far as we know, there is no evidence to include C. fecunda in the South Atlantic fauna. This contribution was supported in part by a Coopera- tive Argentina-Brazil-Chile Research Grant from Funda- cidn Antorchas, Argentina and the project BID 802/OC- AR-PICT No. 01-04321 from the National Agency for Sci- entific and Technical Promotion, Argentina. Two anony- mous reviewers kindly improved the manuscript. Literature Cited CHAPARRO, O. R. & K. A. PASCHKE. 1990. Nurse egg feeding and energy balance in embryos of Crepidula dilatata (Gas- tropoda: Calyptraeidae) during intracapsular development. Marine Ecology Progress Series 65(1):183—191. GALLARDO, C. S. 1976. Historia Natural y reproduccion de Cre- pidula dilatata Lamarck en una poblacion de Bahia Mehuin (Prov. Valdivia, Chile). Medio Ambiente 2(1):44—50. GALLARDO, C. S. 1977. Two modes of development in the mor- phospecies Crepidula dilatata (Gastropoda: Calyptraeidae) from Southern Chile. Marine Biology (Berl.) 39:241—251. GALLARDO, C. S. 1979. Especies gemelas del género Crepidula (Gastropoda, Calyptraeidae) en la costa de Chile; una redes- cripcion de C. dilatata Lamarck y descripcion de C. fecunda n. sp. Studies on Neotropical Fauna and Environment 14: 215-226. GALLARDO, C. S. & O. A. GARRIDO. 1987. Nutritive egg forma- tion in the marine snails Crepidula dilatata and Nucella crassilabrum. International Journal of Invertebrate Repro- duction and Development 11:239—254. MeErRMoD, G. 1950. Les types de la collection Lamarck au Mu- seum de Genéve. Mollusques vivants, I. Revue Suisse de Zoologie 57(34):687—756. Paropiz, J. J. 1939. Las especies de Crepidula de las costas Argentinas. Physis 17:685—709. The Veliger 45(2):175 (April 1, 2002) THE VELIGER © CMS, Inc., 2002 BOOKS, PERIODICALS & PAMPHLETS The Biology of Terrestrial Molluscs Edited by G. M. Barker. 2002. CABI Publishing, Wallingford, UK. xiv + 558 pp. ISBN 0 85199 318 4. Price $US 130.00. With contributions by 22 authors, this volume offers a synthesis of current knowledge and research on land snail and slug biology that will be useful to specialists and general biologists alike. Chapter topics include phyloge- ny, diversity and adaptive morphology (G. M. Barker); body wall form and function (D. L. Luchtel and I. Dey- rup-Olsen); nervous system and sensory organs (R. Chase); radular structure and function (U. Mackenstedt and K. Markel); digestive system structure and function (V. K. Dimitriadis); food and feeding behavior (B. Speis- er); haemolymph and blood cell function (E. Furuta and K. Yamaguchi); structure and functioning of the repro- ductive system (B. J. Gomez); regulation of growth and reproduction (A. Gomot de Vaufleury); spermatogenesis and oogenesis (J. M. Healy); population and conservation genetics (T. Backeljau, A. Baur, and B. Baur); life history strategies (J. Heller); behavioral ecology (A. Cook); and soil biology and ecotoxicology. All chapters contain ex- tensive bibliographies; all were peer-reviewed. I found the text to be exceptionally readable (quite likely a tes- tament to the skill of the editor as well as the authors). Illustrations are not superabundant but are adequate where called for. The result is an authoritative manual that should be a benchmark for terrestrial mollusk biology for years to come. B. Roth The Recent Molluscan Marine Fauna of Isla de Malpelo, Colombia by K. L. KAISER and C. W. Bryce. 2001. The Festivus 33, Occasional Paper 1, 149 pp. Available from San Diego Shell Club, 3883 Mt. Blackburn Ave., San Diego, CA 92111 USA. $US 30.00 within United States; $35.00 Canada and Mexico; $40.00 airmail to destinations outside the United States. Here is another solid contribution from the publication program of the San Diego Shell Club, a spiral-bound, annotated faunal list, thoroughly illustrated with 49 black- and-white plates and five color plates of living mollusks in their natural habitats. The new information contained is largely based on two expeditions by the authors, in 1998 and 2000, during which they systematically sampled the intertidal and subtidal shallow-water habitats of Isla de Malpelo. Their painstaking work increased the known number of mollusk species from Isla de Malpelo and its surrounding waters from 83 to 341. The numerous illus- trations are of uneven but mostly very good quality, in- cluding crisp SEM images of the most minute items. Many small specimens were identifiable only to genus (and in some cases only to family); these are signaled in the list and illustrations as “‘sp. 1,”’ “‘sp. 2” and so forth. The authors have resisted any temptation to describe new taxa; rather, this work will be an invaluable starting point for further study to clarify the identities of these myste- rious customers, and hence the biogeography of the island malacofauna as a whole. ui , Coal f zh eae ¢ s ¢ ‘ || 1a | t { | 1 hon | 5 t i rH i as meane DORA Information for Contributors Manuscripts Manuscripts must be typed, one side only, on A4 or equivalent (e.g., 842” X 11”) white paper, and double-spaced throughout, including references, figure legends, footnotes, and tables. All margins should be at least 25 mm wide. Text should be ragged right (i-e., not full justified). Avoid hyphenating words at the right margin. Manuscripts, in- cluding figures, should be submitted in triplicate. 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Stohler (1 Volume 45 | x 901-2000), Founding Editor July 2, 2002 Se ISSN 0042-3211 Number 3 CONTENTS New information on Late Cretaceous, Paleocene, and Eocene neritid gastropods from the North American Pacific slope RIGEINRC) IL, SOURIS AND ILOWBUUN IR SNUG 56085 dno eben Ge sun oe oes odes oor Review of the genus Actinocyclus Ehrenberg, 1831 (Ophisthobranchia: Doridoidea) IANGEIVADDES Me. 5 alle d ec AIP CNELGART ANE STAR UION SeenON Nera URL Ca OR sah ena Owengriffithsius, a new genus of cyclophorid land snails endemic to northern Madagascar IGEN INEM Els GMP NMIBERM@ Ngee wae, nine mak Oe UL ie 0 ea Me io Gee lates baaa ls Geographic variation of shell geometry in the abyssal snail Xyloskenea naticiformis (Jeffreys, 1883) MICHAEL A. REX, ANNELL BOND, RON J. ETTER, ANDREA C. REX, AND CAROL T. STUART Intermating interval and number of sperm delivered in the simultaneously hermaphroditic land snail Arianta arbustorum (Pulmonata: Helicidae) CLAUDIA HANGGI, ROLF LOCHER, AND BRUNO BAUR... .....2...-22-0220+e20 +> On the adaptive function of the love dart of Helix aspersa IMUICIBINSIL J, ILANIDOUBS 5 Gols ooo sue be Sh dogo 6 be Neu deo gm ued sa eo on daar ond oe Identical carbonic anhydrase contributes to nacreous or prismatic layer formation in Pinctada fucata (Mollusca: Bivalvia) T. MrvyasHita, R. TAKAGI, H. MIYAMOTO, AND A. MATSUSHIRO............22.00- Thin layer chromatographic analysis of lutein and -carotene in Biomphalaria glabrata main- tained on a high fat diet VONGEYVUND KUM eDERNAR DE RIED VAIN) |OSEPE SHERMA 5 .)2 2.15.4 cisiels 2 G22 2 2 = = 2 CONTENTS — Continued Wi, 193 203 218 224 Poi 250 256 The Veliger (ISSN 0042-3211) is published quarterly in January, April, July, and October by the California Malacozoological Society, Inc., % Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105. Periodicals postage paid at Berkeley, CA and additional mailing offices. POSTMASTER: Send address changes to The Veliger, Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105. THE VELIGER Scope of the journal The Veliger is an international, peer-reviewed scientific quarterly published by the Cali- fornia Malacozoological Society, a non-profit educational organization. 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Send all business correspondence, including subscription orders, membership applications, pay- ments, and changes of address, to: The Veliger, Dr. Henry Chaney, Secretary, Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105, USA. Send manuscripts, proofs, books for review, and correspondence regarding editorial matters to: Dr. Barry Roth, Editor, 745 Cole Street, San Francisco, CA 94117, USA. © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). THE VELIGER © CMS, Inc., 2002 The Veliger 45(3):177-192 (July 2, 2002) New Information on Late Cretaceous, Paleocene, and Eocene Neritid Gastropods from the North American Pacific Slope RICHARD L. SQUIRES Department of Geological Sciences, California State University, Northridge, California 91330-8266, USA AND LOUELLA R. SAUL Invertebrate Paleontology Section, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, USA Abstract. Nine species of neritid gastropods from shallow-marine, Upper Cretaceous, Paleocene, and Eocene rocks of the Pacific slope of North America are discussed. Two are new species: Nerita (Bajanerita?) banosensis, sp. nov., from the Upper Cretaceous (Maastrichtian Stage) “‘Quinto Silt’? member of the Moreno Formation, Merced County, north-central California; and Nerita (Theliostyla?) kennedyi, sp. nov. from the upper lower to lower middle Eocene (““Domengine Stage’’) Santiago Formation, near Vista, northern San Diego County, southern California. An immature specimen of Corsania (subgenus?) sp., from unnamed lower Upper Cretaceous (Cenomanian Stage) strata near Dayville, Grant County, east-central Oregon, represents the first confirmed Cenomanian record of a neritid from the Pacific slope of North America. Corsania (Januncia) rhoga Saul & Squires, 1997, previously known only from lower Paleocene strata in Lake County, northern California, is reported from lower? and upper Paleocene strata in Los Angeles County, southern California. The late Paleocene Corsania (Januncia) janus Woods & Saul, 1986, previously known only from Baja California Sur, Mexico, is reported from Santa Cruz Island, southern California. Nerita (Theliostyla) triangulata Gabb, 1869, a widespread Eocene species is reported for the first time from Wash- ington. Previously unknown, early juvenile morphology and color patterns are described for this species. Nerita wash- ingtoniana Weaver & Palmer, 1922, is synonymized with N. (T. ) triangulata, and Nerita cowlitzensis Dickerson, 1915, is questionably synonymized with the latter. Neritina martini Dickerson, 1915, an Eocene species from Washington is tentatively assigned to subgenus Neritina, previously known only from the modern record. INTRODUCTION The sequence of North American Pacific slope Paleo- cene and Eocene molluscan stages used in this report was recently put into the current chronostratigraphic frame- work by Squires (in press). These stages are the follow- ing: “unnamed stage’ (early Paleocene); ‘Martinez Stage’? (late Paleocene); ““Meganos Stage’’ (latest Paleo- cene to earliest Eocene); ““Capay Stage’’ (middle early Eocene); ““Domengine Stage” (late early to early middle Eocene); ““Transition Stage”’ (early middle Eocene); ‘*Te- jon Stage” (middle to late middle Eocene); and Galvinian Stage (late Eocene to earliest Oligocene). These stages, along with the Upper Cretaceous ones, are shown in Fig- Recent field and museum work resulted in the discovery of rare specimens of Late Cretaceous and Early Cenozoic neritid gastropods from the Pacific slope of North Amer- ica. Two new species, a possible new species, and new information about six other previously known species of neritids were the results of this study. The general areas of the type localities of the new species, as well as the new geographic occurrences of these other species, are shown in Figure 1. Neritid gastropods are relatively uncommon in the rock record of the northeastern Pacific. This scarcity is due to a variety of reasons. These gastropods commonly lived ure 2. in rocky shoreline habitats, and these are normally not Abbreviations used are: CAS, California Academy of preserved in the rock record. Also, the record is not con- tinuous because marine neritids, which are warm-water gastropods, only lived in this area during periods of warm climate. In addition, many fossil neritids are overlooked because they resemble naticid gastropods (Saul & Squires, 1997). Sciences, San Francisco; LACM, Natural History Muse- um of Los Angeles County, Malacology Section; LAC- MIP, Natural History Museum of Los Angeles County, Invertebrate Paleontology Section; SDSNH, San Diego Museum of Natural History, San Diego; UCLA, Univer- sity of California, Los Angeles (collections now stored at Page 178 Figure 1. Index map to type localities of the new species and new geographic occurrences of previously named neritids dis- cussed in this study. 1 = “Big Bend” of Cowlitz River near Vader. 2 = Near Dayville. 3 = Los Banos Creek. 4 = Trailer Canyon. 5 = Santa Cruz Island. 6 = Near Vista. LACMIP); UCMP, University of California Museum of Paleontology (Berkeley); UCR, University of California, Riverside; UWBM, University of Washington (Seattle), Thomas Burke Memorial Washington State Museum [= UW in older literature]. The Veliger, Vol. 45, No. 3 Ma OLIGOCENE pg Menten (N.) 40 martini > Zi — N. (7.2) k dyi a= [| (T.?) kennedyi ~ = ; | "Meganos" | Beis Bl (1 me <8} Unnamed | =’ C. (J.) rhoga Maastrichtian a N. (B.?) banosensis 70 80 5 Campanian CRETACEOUS 90 ? 100 = C. (subgenus?) sp. Figure 2. Age and stratigraphic positions of the neritids dis- cussed in this study. Cretaceous stages time scale from Gradstein et al. (1994); Tertiary stages time scale from Squires (in press). Nerita (Theliostyla) triangulata range includes the synonym Ner- ita washingtoniana and the questionable synonym Nerita cow- litzensis. SYSTEMATIC PALEONTOLOGY Family NERITIDAE Rafinesque, 1815 Subfamily NERITINAE Rafinesque, 1815 Genus Corsania Vidal, 1917 Type species: Corsania douvillei Vidal, 1917, by original designation; late Early Cretaceous (Aptian Stage), Cors, Lérida, Spain. Corsania (subgenus?) sp. (Figures 3—5) Description: Shell minute (5.4 mm high), broader than high, consisting of about nearly two whorls, spire lowly elevated, body whorl rapidly expanding; suture im- pressed. Shoulder of body whorl angulate with broad, low-sloping to very slightly concave ramp. Growth lines on ramp prosocline. Body whorl smooth, convex. Aper- ture moderately large. Deck area narrow. Inner lip slightly irregular with several, very minute prominences (teeth?), especially posteriorly. Outer lip smooth. Material examined: Hypotype LACMIP 12905 from LACMIP loc. 9936. Distribution: Unnamed strata about 9.5 km southeast of R. L. Squires & L. R. Saul, 2002 Dayville, Grant County, east-central Oregon (LACMIP loc. 9936). Geologic age: Late Cretaceous (early Cenomanian Stage). Discussion: The only known specimen of this species 1s, most likely, an early juvenile, based on its minute size. It is probably a new species, but it is not named at this time because of the incompleteness of knowledge about its morphology as an adult. To name it would only cause problems for future workers in their attempts to make morphologic comparisons. Squires & Saul (2002) reported an early Cenomanian age and shallow-marine paleoenvironment for the rocks found at LACMIP loc. 9936 near Dayville. They also reported new species of iteriid and actaeonellid gastro- pods from the same locality. The Oregon specimen has a high, wide shoulder and rapidly enlarging body whorl which are like those found in Corsania. This genus is characterized by ornament consisting of spiral ridges with tubercles crossed by col- labral ridges (on portions of the whorls), as well as by teeth on the inner lip (Woods & Saul, 1986). The Oregon specimen does not have any ornament, but this might be the result of having been worn by post-mortem transport, or it could be related to an early juvenile-growth stage of the specimen. The specimen has some very minute irreg- ularities on what appears to be the inner lip. It is possible, however, that the inner lip teeth have been resorbed, which is a common phenomenon in neritids (Woodward, 1892; Cossmann, 1925). Also, it is possible that the deck area, which is a callused area that encompasses the inner lip, has been detached. Broken deck areas are not uncom- mon in neritids, and Squires & Saul (1993) reported a fossil specimen whose deck area had been pushed into the aperture. The specimen from LACMIP loc. 9936 can- not be assigned to a subgenus because of the possibility that the deck area has been detached. There are two rec- ognized subgenera of Corsania; namely, Corsania (Cor- sania) Vidal, 1917, and Corsania (Januncia) Woods & Saul, 1986. Corsania (Januncia) differs from the former by having a strongly depressed (sunken) deck area. The inner edge of this depressed deck area has a nearly Straight trend behind the embellishment of the strong teeth, thereby imparting a double inner lip structure. Bet- ter preserved and more mature specimens of the Oregon species are needed in order to determine the subgenus of this species. This Corsania (subgenus?) sp. is the first Cenomanian record of Corsania from the Pacific coast of North Amer- ica. Corsania (Corsania) allisoni Saul & Squires (1997: _ 139, 141, figs. 22-24) from the Lower Cretaceous (mid- dle Albian) upper member of the Alisitos Formation, Baja California, Mexico, is the earliest Corsania on the Pacific coast of North America and the only other record of this genus in this region. Corsania (Corsania) probably orig- Page 179 inated in the Old World Tethyan paleobiotic province dur- ing the Lower Cretaceous Aptian Stage (Saul & Squires, 1997). Corsania (subgenus?) sp. differs from C. (C. ) allisoni by not having any ornament, but, as mentioned above, this might be the result of poor preservation and/or growth stage. The only other neritid on the Pacific coast of North America that might range into the Cenomanian is the Cre- taceous Otostoma? atopos Saul & Squires (1997:138— 139, figs. 19-21) known from reworked clasts of late Al- bian-early Cenomanian age in the Venado Formation of Late Cretaceous (early Turonian) age, northern Califor- nia. Because of the uncertainty as to exact geologic age of O. ? atopos, Corsania (subgenus?) sp. represents the first confirmed record of a neritid from the Cenomanian Stage of the Pacific slope of North America and extends the northern range of Albian-Cenomanian neritids in this region. Corsania (subgenus?) sp. differs from O.? atopos by having a much lower spire, a low-sloping to slightly concave ramp, and no prominent inner lip teeth. Subgenus Januncia Woods & Saul, 1986 Type species: Corsania (Januncia) janus Woods & Saul, 1986, by original designation; late Paleocene (‘Martinez Stage’’), Baja California, Mexico. Corsania (Januncia) rhoga Saul & Squires, 1997 (Figures 6—8) Corsania (Januncia) rhoga Saul & Squires, 1997:142, figs. 25-27. Holotype: LACMIP 7889. Type locality: LACMIP loc. 7047, unnamed rocks, Lake County, northern California. Other material examined: Hypotype LACMIP 12906 from LACMIP loc. 10508, and a specimen from LAC- MIP loc. 26720. Distribution: Upper part of Santa Susana Formation, Trailer Canyon, Santa Monica Mountains, southern Cal- ifornia (LACMIP locs. 10508 and 26720) and unnamed rocks, Lake County, northern California (LACMIP loc. 7047). Geologic age: Late early? Paleocene (late ‘“‘unnamed stage’’?) to late Paleocene (““Martinez Stage’’). Discussion: Two specimens were found. One is from LACMIP loc. 10508 and is the largest (36.7 mm high and 53 mm wide) and most complete specimen of C. (J.) rho- ga (Figures 6-8). This specimen shows, for the first time, the entire inner lip. Five teeth are present, and the two posteriormost ones are the most developed. The other specimen, which is from LACMIP loc. 26720, is com- plete but does not show the inner lip very well. The new specimens of C. (J.) rhoga from the Santa Page 180 The Veliger, Vol. 45, No. 3 Figures 3-17. All specimens coated with ammonium chloride. Figures 3-5. Corsania (subgenus?) sp., hypotype LACMIP 12905, LACMIP loc. 9936, Dayville area, Oregon, height 5.4 mm, X5.7. Figure 3. Apertural view. Figure 4. Abapertural view. Figure 5. Apical view. Figures 6-8. Corsania (Januncia) rhoga Saul & Squires, 1997, hypotype LACMIP 12906, LACMIP loc. 10508, Santa Monica R. L. Squires & L. R. Saul, 2002 Monica Mountains are only the second and third known specimens of this species. They significantly extend the geographical range of C. (J.) rhoga southward by 650 km and extend the geologic range upward into the late Pa- leocene. At the new locality (LACMIP loc. 10508), C. (J.) rhoga was found in a coralline-algal-rich, micaceous muddy siltstone about 1 m stratigraphically below a 24- m-thick blocky, coralline-algal-limestone interval. The specimens of C. (J.) rhoga were found among numerous specimens of the gastropod Mesalia clarki (Dickerson, 1914) and articulated specimens of the bivalves Plicatula lapidicina Squires & Saul, 1998, and Plicatula trailer- ensis Squires & Saul, 1998. The rocks that compose LACMIP loc. 10508 were interpreted to be of late Paleo- cene age and deposited very nearshore, under tropical to subtropical conditions (Squires, 1993a; Squires & Ken- nedy, 1998; Squires & Saul, 1998). Januncia originated in the Old World Tethyan paleo- biotic province, and the earliest known species is known from the Maastrichtian or Danian of western Iran (Woods & Saul, 1986). Corsania (J.) rhoga is the earliest known species of this subgenus on the Pacific slope of North America. Corsania (Januncia) janus Woods & Saul, 1986 (Figures 9—11) Corsania (Januncia) janus Woods & Saul, 1986:640—-641, figs. 5.1—5.6. Type specimens: Holotype UCLA 59426; paratypes UCLA 59427-59430. Type locality: LACMIP loc. 27083, Sepultura Forma- tion, east of Bahia Sebastian Vizcaino, Baja California, Mexico. Other material examined: Hypotype LACMIP 12907 from LACMIP loc. 23348. Distribution: Sepultura Formation, east of Bahia Sebas- tian Vizcaino, Baja California, Mexico (LACMIP loc. 27083) and Pozo Formation, Well Canyon, Santa Cruz Island, southern California (LACMIP loc. 23348). Geologic age: Late Paleocene (“‘Martinez Stage’’). Discussion: A single specimen is known from the Pozo Formation on Santa Cruz Island. This specimen (Figures Page 181 9-11), which is the largest known for this species, is 30.5 mm high and 39 mm wide. The specimen is well pre- served exteriorly, but interiorly the deck area is very thin and impossible to clean entirely without destroying it. Careful partial cleaning, however, revealed that the deck area is strongly depressed, which is a diagnostic feature of Januncia. The cleaning also revealed three of the six elongate inner lip teeth that characterize Corsania (Jan- uncia) janus. Woods & Saul (1986) mentioned that C. (J.) janus is similar to C. (J.) limata (White, 1887:196, pl. 15, figs. 6, 7) from Paleocene rocks in Brazil, and the Pozo Forma- tion specimen confirms this comparison. Doerner (1969) mentioned the same bed (i.e., LACMIP loc. 23348) that yielded the hypotype (LACMIP 12907) of C. (J.) janus. He reported that the molluscan fauna in this bed had lived in shallow, inshore waters of a semi- tropical to tropical environment. Using the presence of Turritella pachecoensis Stanton, 1896, he assigned a Pa- leocene age to the fauna. Saul (1983) considered T. pa- checoensis to be a subspecies; namely, Turritella infra- granulata pachecoensis Stanton, 1896. Saul (1983) as- signed the rocks from LACMIP loc. 23348 to the ‘‘Mar- tinez Stage” of late Paleocene age. The Pozo Formation specimen of C. (J.) janus provides data on the minimum size of this species’ range, which is relatively large. Previously, this species was known only from the Punta Rosarito area, northern Bahia Sebas- tian Vizcaino, on the western coast of Baja California, Mexico. Today, Santa Cruz Island is about 650 km north of Punta Rosarito. During the Eocene, however, the Pozo Formation was situated 150 km farther south and near what is now known as San Diego. During the Late Ce- nozoic, Santa Cruz Island underwent about 150 km of clockwise tectonic rotation to its present-day position (At- water, 1998), and when this rotation is removed, the Pozo Formation occurrence of C. (J.) janus actually represents only a 500-km-range extension to the north. Genus Nerita Linnaeus, 1758 Type species: Nerita peloronta Linnaeus, 1758, by sub- sequent designation (Montfort, 1810); Recent, South Florida, West Indies, and Bermuda. Mountains, California, height 36.7 mm, 0.9. Figure 6. Apertural view. Figure 7. Abapertural view. Figure 8. Apical view. Figures 9-11. Corsania (Januncia) janus Woods & Saul, 1986, hypotype LACMIP 12907, LACMIP loc. 26720, Santa Cruz Island, California, height 30.5 mm, 1.1. Figure 9. Apertural view. Figure 10. Abapertural view. Figure 11. Apical view. Figures 12—14. Nerita (Bajanerita?) banosensis Squires & Saul, sp. nov., holotype LACMIP 12908, LACMIP loc. 10676, Los Banos Creek, California, height 9 mm, 4.1. Figure 12. Apertural view. Figure 13. Abapertural view. Figure 14. Apical view. Figures 15-17. Nerita (Theliostyla) triangulata Gabb, 1869, hypotype LACMIP 12909, LACMIP loc. 6298, “Big Bend” of Cowlitz River, Washington, height 7.5 mm, 4.1. Figure 15. Apertural view. Figure 16. Lateral view. 17. Abapertural view. Page 182 Subgenus Bajanerita Squires, 1993 Type species: Nerita (Bajanerita) californiensis (White, 1885), by original designation; Late Cretaceous, Baja California, Mexico. Discussion: Bajanerita has an inner lip with a convex trend, and this is one of the main distinguishing features of this subgenus. Re-examination of many specimens of the type species of Bajanerita revealed that this genus is also characterized by the presence of a subsutural collar anterior to the suture. Strength of this collar is variable. In addition, the growth lines change from prosocline to nearly straight as they pass from the shoulder onto the collar area. This subsutural collar and its variability in strength are evident in photographs provided by Squires (1993b:figs. 2.3, 2.4, 2.6, 2.8). Nerita (Bajanerita?) banosensis Squires & Saul, sp. nov. (Figures 12—14) Diagnosis: Smooth shell, barely elevated spire, inner lip with four squarish teeth, and a moderately swollen callus. Description: Shell small (9 mm high), naticiform/neri- tiform, convex, thin-shelled, consisting of approximately 2% whorls; spire barely elevated, body whorl rapidly ex- panding, early whorls nearly hidden by body whorl; su- ture impressed. Subsutural collar anterior to suture very faint. Body whorl smooth. Growth lines prosocline. Ap- erture moderately large, subcircular; apertural opening moderately narrow. Deck callus moderately swollen, smooth. Trend of inner lip convex; inner lip with four teeth, squarish, equidistant; posteriormost tooth strongest. Outer lip smooth. Dimensions of holotype: Height 9 mm, width 8 mm. Holotype: LACMIP 12908. Type locality: LACMIP loc. 10676, 36°59'28’N, 120°55'50"W, Moreno Formation, informal ‘‘Quinto Silt”’ member (see Anderson, 1958), Los Banos Creek, Merced County, north-central California. Other material examined: A specimen from LACMIP loc. 10676, and a specimen from LACMIP loc. 10685. Distribution: “‘Quinto Silt’? member of Moreno Forma- tion, Los Banos Creek, Merced County, north-central Cal- ifornia (LACMIP locs. 10676 and 10685). Geologic age: Late Cretaceous (middle Maastrichtian Stage). Discussion: Three specimens were found. Two are from LACMIP loc. 10676, and of these, one is complete and the other is a fragment. The specimen from LACMIP loc. 10685 is also a fragment. Both localities are in close proximity to each other in Los Banos Creek. The spire The Veliger, Vol. 45, No. 3 on the holotype is slightly crushed, and the growth lines on the body whorl are poorly preserved, especially in the vicinity of the suture. None of the specimens shows any teeth on the outer lip, but this might just be a function of growth. The new species has a convex inner lip, a very faint subsutural collar, and the additional following features of Bajanerita: smooth body whorl and several squarish teeth on the inner lip. The new species, however, has four teeth on the inner lip, whereas Bajanerita has only three. The new species might belong to Bajanerita or to a closely allied subgenus. Bajanerita is known only from the Pacific slope of North America. Its earliest record is Nerita (Bajanerita) californiensis (White, 1885), from the Upper Cretaceous (upper Campanian to lower Maastrichtian stages) Rosario Formation at Punta Banda, Baja California, Mexico, and Jalama Formation, Santa Barbara County, southern Cali- fornia (Saul & Squires, 1997). Ascending biostratigraph- ically, two additional possible species of Bajanerita are the following: “‘Capay Stage’? Nerita (Bajanerita?) larix Saul & Squires, 1997, from the upper part of the Crescent Formation, southwestern Washington; and Galvinian Stage Nerita (Bajanerita?) vokesi Durham, 1944, from southwestern Washington (Saul & Squires, 1997). The new species differs from Nerita (Bajanerita) cal- iforniensis (White, 1885:pl. 5, figs. 7, 8; Squires, 1993b, figs. 2.1-2.8) by having a much lower spire, a much weaker subsutural collar, four rather than three inner lip teeth, a wider callus, and no outer lip teeth. The new species differs from Nerita (Bajanerita?) larix Saul & Squires (1997:136—137, figs. 9-11) by having a much lower spire, wider inner lip teeth, and no outer lip teeth. The new species differs from Nerita (Bajanerita?) vokesi Durham (1944:156, pl. 17, figs. 11, 12) by having an inner lip with a convex rather than a straight trend and a larger shell size. There might be other differences, but as Saul & Squires (1997) pointed out, the morphology of XN. (B.?) vokesi is poorly known. At both localities in Los Banos Creek where the new species was found, the bivalve Glycymeris banosensis Anderson, 1958, is very abundant. Saul (1983) referred to this bivalve as Glycymeris (Glycymerita?) banosensis and interpreted that the specimens are in situ and that they lived in a shallow-water environment. Also present at LACMIP loc. 10685 is the bivalve Calva (Calva) varians (Gabb, 1864) of middle to late Maastrichtian age (Saul & Popenoe, 1992), the gastropod Gyrodes (Sohlella) ex- pansus Gabb, 1864, of middle to late? Maastrichtian age (Popenoe et al., 1987), and the gastropod Perissitys stan- toni (Stewart, 1927) of late Maastrichtian age (Popenoe & Saul, 1987). Based on association with these last-men- tioned three species, the new species is assigned a middle Maastrichtian age, near the middle-late Maastrichtian boundary. R. L. Squires & L. R. Saul, 2002 Etymology: The species is named for Los Banos Creek, California where the type locality of the new species is located. Subgenus Theliostyla Morch, 1852 Type species: Nerita albicilla Linnaeus, 1758, by sub- sequent designation (Kobelt, 1879); Recent, Indo-Pacific. Nerita (Theliostyla) triangulata (Figures 15—27) Nerita (Theliostyla) triangulata Gabb, 1869:170, pl. 28, figs. 52, 52a; Vokes, 1939:182, pl. 22, figs. 31, 33, 34; Giv- ens, 1974:61, pl. 5, fig. 4; Givens & Kennedy, 1976: 960, 963, pl. 1, figs. 1-4; Devjatilova & Volobueva, 1981:108, pl. 9, figs. 2-4; Squires, 1987:23, fig. 14; 1992:325-327, figs. 2-18; 1994:48, pl. 2, fig. 6; Olei- nik, 1998:383—384, pl. 3, figs. 1, 2. Nerita triangulata Gabb: Arnold, 1910:14, pl. 14, figs. 12, 12a (figs. repeated in Arnold & Anderson, 1910:pl. 26, figs. 12, 12a); Hanna, 1927:301, pl. 46, figs. 11, 12, 16, 17; Moore, 1968:28, pl. 12a. ? Nerita cowlitzensis Dickerson, 1915:58—59, pl. 5, figs. 7a, b; Weaver, 1943:294—295, pl. 63, fig. 11; Nesbitt, 1995: table 1. Nerita washingtoniana Weaver & Palmer, 1922:28—29, pl. 11, fig. 4); Weaver, 1943:295, pl. 64, fig. 8. Nerita triangulata Gabb var. oregonensis Merriam & Turner, 1937:104, pl. 6, fig. 5; Turner, 1938:95, pl. 19, figs. 10— 12; Weaver, 1943:295-296, pl. 64, figs. 10, 13. Nerita n. sp.: Clark, 1938:701, pl. 4, fig. 6. Nerita quadrangulata Weaver & Kleinpell, 1963:183, pl. 23, fig. 1. Description of juveniles: Shell minute (2 to 5 mm high), broader than high, with rapidly expanding body whorl. Spire very low to flattened, apex usually depressed. Pos- terior part of dorsal surface elevated. Dorsal surface with extremely faint and noded spiral ribs or with distinct, noded spiral ribs. Body whorl with carinate shoulder and, usually, another carina a short distance anteriorly. Very closely spaced, unnoded spiral ribs cover most of body whorl, except near base of whorl. Anteriormost spiral rib carinalike toward outer lip. Aperture large, quadrate (rare- ly elliptical). Outer lip flared with seven to 10 teeth, not extending to outer lip periphery. Two posteriormost teeth stronger than rest, with tooth next to posteriormost tooth strongest. Three to four small, subequal teeth medially. Deck with five to six granules, arranged loosely in rows. Color bands axial, wavy or non-wavy; some non-wavy bands bifurcate and others do not extend to shell apex. Growth lines prosocline. Holotypes: Of N. (7.) triangulata, type material missing (fide Keen & Bentson, 1944:179). Of N. cowlitzensis. CAS 183.02 [= CAS 290]; of N. washingtoniana CAS 66548.01 [= UW 197 = CAS 7591]. Type localities: Of N. (7.) triangulata, (exact location unknown), Domengine Formation, New Idria area, San Page 183 Benito County, central California. Of N. cowlitzensis, UWBM loc. 232, Cowlitz Formation, Lewis County, southwestern Washington. Of WN. washingtoniana, UWBM loc. 329, Cowlitz Formation, Lewis County, southwestern Washington. Other material examined: Hypotypes LACMIP 12909 to 12911 and seven other specimens from “Big Bend” of Cowlitz River, east of Vader, Lewis County, south- western Washington. Distribution: San Diego, southern California to south- western Washington; also present in northwestern Kam- chatka. Geologic age: Late Paleocene (‘‘Martinez Stage’’) through late middle Eocene (‘“Tejon Stage’’). ““MARTI- NEZ” to “MEGANOS”-“CAPAY” STAGES UNDIF- FERENTIATED: Kamchikskaya Formation and Tkapra- vayamskaya Formation, Cape Getkilnin, northwestern Kamchatka (Oleinik, 1998); ““CAPAY STAGE”’: Capay Formation, Yolo County, northern California and White Tail Ridge formation (informal) [formerly referred to as the upper Umpqua formation (informal) and the Look- inglass Formation (see Squires, 1998)], southwestern Oregon (Merriam & Turner, 1937; Turner, 1938); ‘“‘DO- MENGINE STAGE”: Delmar Formation, San Diego, southern California (Hanna, 1927; Givens & Kennedy, 1979; “‘Santiago Formation”’ (formerly referred to as the Delmar Formation, in the Vista area, northern San Diego County (Givens & Kennedy, 1976; Squires, 1992); Ma- tila Sandstone, Pine Mountain area, Ventura County, southern California (Givens, 1974); Matilija Sandstone?, Whitaker Peak area, Ventura County, southern California (Squires, 1987); Domengine Formation, Coalinga area, central California (Vokes, 1939). ““TEJON STAGE”: Sa- cate Formation-‘‘Coldwater’’ Sandstone [formerly re- ferred to as the undifferentiated Sacate-Gaviota Forma- tion, Santa Barbara County, southern California (see Squires, in press)] (Weaver & Kleinpell, 1963); Markley Formation, Solano County, northern California (Clark, 1938); Cowlitz Formation, Lewis County, southwestern Washington (new information). Discussion: Even though the shallow-marine to brackish- marine Nerita (Theliostyla) triangulata is the most geo- graphically widespread (and the most geologically long- ranging) neritid gastropod in the Paleogene rock record of the northern Pacific, it is reported here for the first time from Washington. The Washington specimens (a to- tal of 10) are all from the upper middle Eocene Cowlitz Formation (“‘Tejon Stage’) in the vicinity of the “Big Bend” of the Cowlitz River, east of Vader, Lewis County. The Cowlitz Formation was deposited at an estimated pa- leolatitude of 40°N to 45°N, in warm-tropical to subtrop- ical, shallow-marine and marginal-marine environments associated with a prograding river-dominated delta (Nes- bitt, 1995). This formation is chronostratigraphically near The Veliger, Vol. 45, No. 3 Page 184 R. L. Squires & L. R. Saul, 2002 the top of the ““Tejon Stage’? and ranges in age from approximately 39 to 36 Ma (Nesbitt, 1995; Squires, in press). The occurrence of N. (T.) triangulata in ‘‘Tejon Stage’’ rocks in Washington reinforces how far north warm-water mollusks ranged during the middle to late Eocene on the Pacific slope of North America. Nerita (T.) triangulata is a rare taxon in the Cowlitz Formation (E. Nesbitt, personal communication). The largest known specimen (7.5 mm high) of this species from this formation is illustrated in Figures 15-17. This specimen shows all the diagnostic morphologic features described by Squires (1992) for Nerita (Theliostyla) triangulata. All the other known specimens of N. (T.) triangulata from the Cowlitz Formation are juveniles, and most of these are between 2 and 3 mm high. A few show color patterns. Many of the juvenile specimens from this formation were collected in bulk samples taken from LACMIP loc. 6297 by R. L. Squires. The morphology of the juvenile stage of N. (7.) triangulata was previously not known. The holotype of Nerita washingtoniana Weaver & Palmer, 1922, is a worn juvenile 2 mm high (Figures 25— 27). Unfortunately, the shell on the body whorl is miss- ing. The overall shape of the shell and the morphological details of the aperture are identical to that of Nerita (The- liostyla) triangulata, although the granules on the deck area are less prominent because of abrasion. Nerita wash- ingtoniana, therefore, is synonymized with WN. (T.) trian- gulata. Weaver & Palmer (1922:295) mentioned that the color bands on their species “‘extend regularly over the surface of the body whorl without a zigzag or wavy pat- tern.” They did not illustrate a specimen showing this original coloration, nor did they give a catalog number to any specimen that shows it. The specimen illustrated in Figures 22—24 fits their description, and this specimen was collected by R. L. Squires. The holotype of Nerita cowlitzensis Dickerson, 1915, is a juvenile 5 mm high (Figures 28—30). It is a somewhat worn specimen, and the early part of the body whorl is missing its shell. Although the carina on the body whorl shoulder is evident, other carinae are poorly evident, and this is probably because of abrasion. A second carina, a Page 185 short distance anterior to the body whorl shoulder, is very faint. Dickerson (1915) reported that the shoulder of Nerita cowlitzensis is less angulated than N. (7.) triangulata. Squires (1992) reported that N. cowlitzensis differs from N. (T.) triangulata by being smaller, nodose only on the dorsal surface, body whorl with only minute sculpture, and aperture more elongate. The apparent differences of angulation and sculpture could be explained by taking into account that the holotype of N. cowlitzensis is a worn specimen of an early juvenile. The aperture of the holo- type of N. cowlitzensis is more elongate than is common in specimens of N. (T.) triangulata. This greater elonga- tion might be the result of slight distortion during post- burial compaction, or it might be the result of a paleoen- vironmental factor. Better preserved specimens of JN. cowlitzensis, however, are needed to positively confirm whether or not these species are the same. We question- ably synonymize them because, other than the apparent differences mentioned above, their deck areas, inner lips, and outer lips are identical. Nerita (Theliostyla?) kennedyi Squires & Saul, sp.nov. (Figures 31—34) Diagnosis: A globose Theliostyla with a flattened spire, rounded body whorl, convex ramp, numerous subequal spiral ribs, low wrinkles and elongate nodes on deck cal- lus, and a color pattern consisting of alternating collabral bands of light and dark. Description: Shell medium small, broader than high, glo- bose, 2%4 whorls, with rapidly expanding body whorl. Up- permost spire flattened, apex immersed. Suture im- pressed. Ramp convex. Body whorl shoulder rounded. Earliest 1% whorls smooth, rest of teleoconch covered with numerous narrow, closely spaced spiral ribs with interspaces narrower than ribs; three to four spiral ribs on rounded body whorl shoulder slightly stronger and more widely spaced than elsewhere; spiral ribs on medial part of body whorl can be somewhat narrower with narrower Figures 18-34. Specimens coated with ammonium chloride, unless otherwise noted. Figures 18-27. Nerita (The- liostyla) triangulata Gabb, 1869, Vader area, Washington. Figures 18-21. Hypotype LACMIP 12910, LACMIP loc. 22536, height 3 mm. Figure 18. Apertural view (uncoated), X11. Figure 19. Lateral view, X10. Figure 20. Aba- pertural view, X11. Figure 21. Apical view (uncoated), x10. Figures 22—24. Hypotype LACMIP 12911, LACMIP loc. 6297, height 2 mm, 16.5. Figure 22. Apertural view. Figure 23. Abapertural view (uncoated). Figure 24. Apical view (uncoated). Figures 25-27. Holotype CAS 66548.01 of Nerita washingtoniana Weaver & Palmer, 1922, height 2 mm, 16.5. Figure 25. Apertual view. Figure 26. Abapertual view. Figure 27. Apical view. Figures 28— 30. ? Nerita (Theliostyla) triangulata Gabb, 1869, holotype CAS 183.02 of Nerita cowlitzensis Dickerson, 1915, height 5 mm, X5.4. Figure 28. Apertural view. Figure 29. Abapertural view. Figure 30. Apical view. Figures 31— 34. Nerita (Theliostyla?) kennedyi Squires & Saul, sp.nov., holotype SDSNH 67066, SDSNH loc. 4105, Vista area, California, height 14.7 mm, X2.2. Figure 31. Apertural view. Figure 32. Lateral view (uncoated). Figure 33. Aba- pertural view (uncoated). Figure 34. Apical view (uncoated). Page 186 interspaces than elsewhere. Spiral ribs minutely beaded on ramp and near base of body whorl. Aperture large, quadrate. Outer lip flared, smooth. Outer lip interior with approximately 17 evenly spaced teeth not extending to outer lip periphery, but extending a short distance inte- riorly; eight medial teeth strongest, others become in- creasingly weaker posteriorly or anteriorly; teeth tend to align with spiral ribs on exterior of shell. Inner lip with eight teeth; two posteriormost ones strongest (tooth | re- moved from being the posteriormost the strongest), next three teeth slightly weaker, and anteriormost three the weakest. Deck area sharply demarcated from shell; broad and callused, with about 12 very loosely arranged, trans- verse rows of low ridges or wrinkles (on posterior part of deck and coincident with spiral ribs) and elongate nodes (on anterior part of deck) somewhat coincident with inner lip teeth. Original color pattern with alternating collabral bands of light and dark, with zigzag borders. Growth lines prosocline. Dimensions of holotype: Height 14.7 mm, width 18 mm. Holotype: SDSNH 67066. Type locality: SDSNH 4105, 33°09'45"N, 117°12'37’W, Santiago Formation, near Vista, northern San Diego County, southern California. Other material examined: Two specimens from SDSNH loc. 3522. Distribution: Santiago Formation near Vista, northern San Diego County, southern California (SDSNH locs. 3522 and 4105). Geologic age: Late early to early middle Eocene (‘‘Do- mengine Stage’’). Discussion: Three specimens were found. A complete and exceptionally well preserved one (holotype) is from SDSNH loc. 4105, which is from the same general lo- cation of UCR loc. 4865 reported by Givens & Kennedy (1976). They reported that the mollusks at UCR loc. 4865 are indicative of the “‘Domengine Stage’’ and that they lived in a low-energy, very shallow (O—30 m) brackish- water Or marine environment, perhaps a lagoon or estu- ary. The other two specimens of the new species are partial specimens from SDSNH loc. 3522. The mollusks at this latter locality are also indicative of the ‘“‘Domengine Stage”’ and lived in a brackish-marine lagoon and were transported a short distance seaward and concentrated within a channel complex, along with land-plant remains (Squires, 1992). Theliostyla probably originated in the Old World Te- thyan paleobiotic province and immigrated to the Pacific slope of North America during the late Paleocene. The earliest record of this subgenus in the rock record of the northeastern Pacific is Nerita (Theliostyla) n. sp.? Woods The Veliger, Vol. 45, No. 3 & Saul, 1986, of probable late Paleocene age in Baja California. Ascending biostratigraphically, the other known species of Theliostyla, besides the new species, from the Pacific slope of North America are the follow- ing: ““Capay Stage”’ Nerita (Theliostyla) olympia Squires & Goedert, 1994, from southwestern Washington; “‘Ca- pay Stage” through “Tejon Stage’’ Nerita (Theliostyla) triangulata Gabb, 1869 (see previous discussion) from widespread localities; ““Tejon Stage’’ Nerita (Theliostyla) crooki Clark, 1938, from northern California; middle Miocene Nerita (Theliostyla) sp. from southern California (Susuki, 1978); middle Miocene Nerita (Theliostyla?) jJoaquinensis Addicott, 1970, from central California; and Pleistocene to Recent Nerita (Theliostyla) funiculata Menke, 1851 [invalid synonym: WNerita (Theliostyla) bernhardi Récluz, 1850] from Pleistocene rocks in Baja California (Durham, 1950) and living in warm waters of Baja California through the Gulf of California and south- ward to Peru and the Galapagos Islands (Keen, 1971). Theliostyla is normally characterized by granules (pus- tules) on the deck area. On some species, both fossil and modern, however, there can be considerable variability in the shape of the granules. Specimens of Nerita (T.) trian- gulata provide an Eocene example. Examination of 43 well preserved late juvenile to adult individuals from SDSNH loc. 4105 revealed a gradation (independent of size) from specimens having only well developed gran- ules on the callus (many specimens) to those having only wrinkles on the callus (few specimens). In some cases, the wrinkles are coincident with spiral ribs, just as on the new species. Specimens of Nerita (T.) funiculata provide a modern example. Examination of about 100 juvenile to early adult individual specimens collected by R. L. Squires from Bahia de Los Angeles in the Gulf of Cali- fornia revealed a gradation (independent of size) from specimens having predominantly granules on the callus (most specimens) to those having only wrinkles on the callus (few specimens). Again, the wrinkles are usually coincident with spiral ribs. Some specimens of N. (T.) funiculata even have an almost smooth-deck callus. The deck area of the new species is known only from the holotype. Although its deck does not have the com- pletely granular ornament that is commonly found in specimens of Theliostyla, it could be argued that the new species is within the range of morphology found within the subgenus. However, until specimens, found by future collecting, show the presence of granules on the deck area, it seems prudent to questionably assign the new spe- cies to Theliostyla. The new species is very similar to those specimens of Nerita (Theliostyla) triangulata Gabb (1869:170, pl. 28, figs. 52, 52a) that have no carinae on the late part of the body whorl. Squires, (1992:323-329, figs. 1-18) re- viewed N. (T.) triangulata, a moderately common gastro- pod in lower and middle Eocene rocks of the Pacific slope of North America. Based primarily on specimens from R. L. Squires & L. R. Saul, 2002 Page 187 38 Figures 35—40. All specimens coated with ammonium chloride. Figures 35-37. Neritina (Neritina?) martini Dickerson, 1915, holotype CAS 291, CAS loc. 193, Vader area, Washington, height 18 mm, 1.7. Figure 35. Apertural view. Figure 36. Abapertural view. Figure 37. Apical view. Figures 38—40. Neritina (Neritina) pulligera Linnaeus, 1766, hypotype LACM 152685, Tjilatjap, Java, height 24 mm, 1.5. Figure 38. Apertural view. Figure 39. Abapertural view. Figure 40. Apical view. SDSNH loc. 3522, which is one of the localities where the new species was found, Squires found that most spec- imens of N. (7.) triangulata have three carinae on the body whorl, some specimens show a gradation from three strong carinae on the early part of the body whorl to faint carinae or no carinae on the late part of the body whorl. The new species differs from N. (T.) triangulata by hav- ing no carinae whatsoever on the early part of the body whorl. In addition, the new species differs in the follow- ing ways: larger and more globose, slightly stronger spiral ribs, much less beaded spiral ribs, and color pattern ar- ranged in collabral bands. Associated with the new spe- cies at SDSNH loc. 4105 are abundant and exceptionally well preserved specimens of N. (T.) triangulata. The new species is also very similar to Nerita (The- liostyla) crooki Clark (1938:700, pl. 4, figs. 1, 2) from the middle Eocene (“‘Tejon Stage’’) Markley Formation, northern California. The new species differs from N. (7.) crooki by having mostly unbeaded spiral ribs and by hav- ing weaker teeth on the posterior part of the inner lip. The nomenclature of the formation that contains the type locality of the new species has been in a state of flux in recent years. Givens & Kennedy (1976) referred to the strata as unnamed. Eisenberg & Abbott (1991) as- signed the strata to the Delmar Formation, and Squires (1992) followed this assignment. Walsh (1996) assigned the strata to the Santiago Formation, and this usage is followed in this paper. Etymology: The species is named for George L. Ken- nedy, who informed the authors about the specimens of the new species. Genus Neritina Lamarck, 1816 Type species: Nerita pulligera Linnaeus, 1766 (ICZN opin. 119, 1931); Recent, southwest Pacific. Subgenus Neritina sensu stricto Discussion: Neritina sensu stricto is low spired and has a smooth or finely dentate inner lip. It has an outer lip that overrides the body whorl and forms a projecting point in the spire area. It also has a very slightly sinuous inner lip (Keen & Cox, 1960) (Figures 37—39). The ho- lotype of Neritina martini Dickerson, 1915, discussed be- low, does not have this projecting point, and its absence is most likely because of poor preservation of this very delicate feature or because of abrasion. The holotype of N. martini also has a straight inner lip, and this difference, along with a lack of information about the projecting point, makes the subgeneric assignment of N. martini ten- tative. Neritina (Neritina?) martini Dickerson, 1915 (Figures 35—37) Neritina martini Dickerson, 1915:59, pl. 5, figs. 8a,b; Weav- er, 1943:296, pl. 63, fig. 10. Holotype: CAS 291. Page 188 Type locality: CAS loc. 183, Cowlitz Formation, Lewis County, southwestern Washington. Other material examined: None. Distribution: Cowlitz Formation, Lewis County, south- western Washington (CAS loc. 183). Geologic age: Late middle Eocene (‘‘Tejon Stage’’). Discussion: This species is known only from the holo- type, which is an adult specimen (height 18 mm, diameter 21 mm) that is well preserved, except for the apical area. Dickerson’s (1915:pl. 5, fig. 8a) illustration of the aper- tural view of the holotype of N. (N.) martini shows the inner lip, whereas Weaver’s (1943:pl. 63, fig. 10) illustra- tion of the same view of this specimen shows the aperture plugged with modeling clay. Neritina is a littoral zone or fresh-to brackish-water gastropod (Firsich & Kauffman, 1984). Its presence in the Cowlitz Formation is extremely rare, but is compati- ble with the deltaic setting of the formation. Contempo- raneous environments on this delta included brackish-wa- ter areas in mudflats and marshes, as well as a freshwater lake within the marshes, all in close proximity to near- shore-marine habitats (Nesbitt, 1995). Cossmann (1925) reported the geologic range of Ner- itina (Neritina) as Middle Jurassic to Recent, whereas Keen & Cox (1960) reported it as Recent only. The latter workers, however, did report the geologic range of Ner- itina sensu lato as Eocene to Recent. Inconsistencies such as these are a reflection of the poor state of knowledge of this group of neritids, which is represented by a paucity of well preserved specimens. Without adequate informa- tion about the inner lip and deck area, workers have been understandably uncertain about the identification of the specimens. Although early workers reported several species of Neritina and Neritina? from Jurassic and Cretaceous rocks of the western interior of the United States (see Boyle, 1893, for a summation), nearly all of these species subsequently have been re-evaluated and assigned to oth- er genera (e.g., Yen, 1946, 1951; Sohl, 1965; Fiirsich & Kauffman, 1984). At least two species have been retained in Neritina; namely, Neritina insolita Stephenson (1952: 146, pl. 54, figs. 6-8) from the Upper Cretaceous (Cen- omanian Stage) Woodbine Formation of Texas and Ner- itina sp. (Dockery, 1993) from Upper Cretaceous (Maas- trichtian Stage) strata in Mississippi. The species of Neritina from Paleocene and Eocene rocks of Paris Basin, France have also been reassigned to other genera (Le Renard & Pacaud, 1995:90). Further- more, it seems to us that the lower Eocene Neritina un- identa Aldrich (1911:13, pl. 5, figs. 7, 8), which is the only reported species of Neritina from the Paleogene of the Gulf coast of the United States, should be placed in genus Neritoplica Oppenheim, 1892, based on the overall The Veliger, Vol. 45, No. 3 shape of the shell and the presence of a single projecting tooth on the inner lip. An exhaustive study of all fossil occurrences of Neri- tina is beyond the scope of this present investigation, but our rudimentary review of the literature indicates that Neritina sensu lato is a rare taxon whose earliest known record is probably the early Late Cretaceous (Cenoman- lan). In addition to Neritina (N.?) martini, the only fossil record of Neritina on the Pacific slope of North America includes Neritina (Dostia) cuneata (Gabb, 1864) from Upper Cretaceous (Campanian Stage) strata of northern California and N. (D.) aff. N. (D.) cuneata (Gabb) of Woods & Saul, 1986, which is a very similar, if not con- specific form, from the Upper Cretaceous (Maastrichtian Stage) Tierra Loma Sandstone Member of the Moreno Formation of north-central California (Woods & Saul, 1986). Dostia Gray, 1842, is patelliform with seven to nine ridgelike teeth and is morphologically quite distinct from Neritina sensu stricto. The only modern record of Neritina on the Pacific slope of North America is Neritina (Clypeolum) latissima Broderip, 1833, known from Acapulco, Mexico to Ec- uador (Keen, 1971). Clypeolum Récluz, 1842, has a large flaring aperture and is morphologically quite distinct from Neritina sensu stricto. Neritina (N.?) martini is most like Neritina (Neritina) pulligera, a modern species and the type species of Ner- itina (Neritina). Mlustrations of this type species are pro- vided in Figures 38—40. Neritina (N.?) martini differs from N. (N.) pulligera by having a more elliptical shape, straight inner lip, and more incised growth lines. As men- tioned earlier, whether or not Neritina (N. ?) martini has an outer lip that overrides the body whorl as a projecting point in the spire area cannot be determined. One other North American fossil species of Neritina has been compared to Neritina (N.) pulligera. Stephenson (1952) reported Neritina insolita Stephenson from the Woodbine Formation (Cenomanian) of Texas to be very similar to Neritina pulligera. Neritina (N.?) martini and N. insolita are also similar and both have a straight inner lip, but the former differs from N. insolita by having den- ticles on the inner lip and having no spiral ribs on the shell. Acknowledgments. Conrad Carrle (formerly a geology student at California State University, Northridge) found the large spec- imen of Corsania (Januncia) rhoga and kindly donated it. George L. Kennedy (California State University, San Diego) found the unusual specimens of Nerita (Theliostyla) from the Vista area, recognized their significance, and informed the au- thors about them. Lindsey T. Groves (LACMIP) allowed access to collections and obtained difficult-to-find literature. LITERATURE CITED AppicotT, W. O. 1970. Miocene gastropods and biostratigraphy of the Kern River area, California. U.S. Geological Survey Professional Paper 642:1—174, pls. 1-21. R. L. Squires & L. R. Saul, 2002 Avpricu, T. H. 1911. New Eocene fossils from the southern Gulf states. Bulletins of American Paleontology 22:1—24, pls. 1-5. ANDERSON, E M. 1958. Upper Cretaceous of the Pacific coast. The Geological Society of America Memoir 71:1—378, pls. 1-75. ARNOLD, R. 1910. Paleontology of the Coalinga district, Fresno and Kings counties, California. U.S. Geological Survey Bul- letin 396:1—173, pls. 1-30. ARNOLD, R. & R. ANDERSON. 1910. Geology and oil resources of the Coalinga district, California. U.S. Geological Survey Bulletin 398:1—354, pls. 1-62. ATWATER, T. M. 1998. Plate tectonic history of southern Cali- fornia with emphasis on the western Transverse Ranges and northern Channel Islands. Pp. 1-8 in P- W. Weigand (ed.), Contributions to the Geology of the Northern Channel Is- lands, Southern California. Pacific Section, American As- sociation of Petroleum Geologists Miscellaneous Publication 45: Los Angeles, California. Boye, C. B. 1893. A catalogue and bibliography of North America Mesozoic Invertebrata. U.S. Geological Survey Bulletin 102:1—315. BRODERIP, W. J. 1832—1833. Characters of new species of Mol- lusca and Conchifera, collected by Mr. Cuming. Proceedings of the Zoological Society of London, for 1832, variously paged. Cviark, B. L. 1938. Fauna from the Markley Formation (upper Eocene) on Pleasant Creek, California. Bulletin of the Geo- logical Society of America 49:683—730, pls. 1—4. CossMANN, M. 1925. Essais de Paléoconchologie Comparée. Pri- vately published: Paris. Volume 13, 345 pp., 11 pls. DevyaTILovA, A. D. & V. I. VoLoBueva. 1981. Atlas of Paleo- gene and Neogene Fauna of the Northeast USSR. Central Combined Thematic Expedition of the Northeast Industrial Geological Society, 219 pp., 55 pls. [in Russian. ] DICKERSON, R. E. 1914. Fauna of the Martinez Eocene of Cali- fornia. University of California Publications, Bulletin of the Department of Geology 8(6):61—180, pls. 6-18. DICKERSON, R. E. 1915. Fauna of the type Tejon: its relation to the Cowlitz phase of the Tejon group of Washington. Pro- ceedings of the California Academy of Sciences, 4th series, 5(3):33-98, pls. 1-11. Dockery, D. T., m1. 1993. The streptoneuran gastropods, exclu- sive of the Stenoglossa, of the Coffee Sand (Campanian) of northeastern Mississippi. Mississippi Department of Envi- ronmental Quality, Office of Geology, Bulletin 129:1—191, pls. 1-42. DOERNER, D. P. 1969. Lower Tertiary biostratigraphy of south- western Santa Cruz Island. Pp. 17—29 in D. W. Weaver (ed.), Geology of the Northern Channel Islands. Pacific Sections, American Association of Petroleum Geologists & Society of Economic Paleontologists and Mineralogists, Special Pub- lication. DurHaM, J. W. 1944. Megafaunal zones of the Oligocene of northwestern Washington. University of California Publica- tions, Bulletin of the Department of Geological Sciences 27(5):101—212, pls. 13-18. DurHAM, J. W. 1950. Megascopic paleontology and marine stra- tigraphy. Pp. 1-216, pls. 1-48 in 1940 E. W. Scripps Cruise to the Gulf of California. The Geological Society of America Memoir 43. EISENBERG, L. I. & P. L. ABBotr. 1991. Middle Eocene paralic facies, northern San Diego County, California. Pp. 55-72 in P. L. Abbott & J. A. May (eds.), Eocene Geologic History San Diego Region. Pacific Section, Society of Economic Pa- Page 189 leontologists & Mineralogists, Book 68: Los Angeles, Cal- ifornia. Fursicu, FE T. & E. G. KAUFFMAN. 1984. Palaeoecology of mar- ginal marine sedimentary cycles in the Albian Bear River Formation of south-western Wyoming. Palaeontology 27(pt. 3):501—536. Gass, W. M. 1864. Description of the Cretaceous fossils. Cali- fornia Geological Survey, Palaeontology 1:57—243, pls. 9— 32. Gass, W. M. 1869. Cretaceous and Tertiary fossils. 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KoBELT, W. 1877-1881. In: Martini & Chemnitz, Neue Ausgabe. Niiremberg. LAMARCK, J. B. 1809. Philosophie Zoologique 1. Paris. 428 pp. LAMARCK, J. B. 1816. Tableau Encyclopédique et Méthodique des Trois Régnes de la Nature. Paris. Le RENARD, J. & J. -M. PAcAuD. 1995. Révision des mollusque Paléogénes du bassin de Paris. I. List des references pri- maires des especes. Cossmanniana 3(3):65—132. LINNAEUS, C. 1758. Systema Naturae per Regna Tria Naturae. Tomus |. Editio decima, reformata. Salvii: Holmiae. 824 pp. LINNAEUS, C. 1766-1767. Systema Naturae per Regna Tria Na- turae. Tomus 1. Editio duodecima, reformata. Salvii: Hol- miae. 1327 pp. MENKE, K. T. 1850-1851. Conchylien von Mazatlan, mit kri- Page 190 tischen Anmerkungen. Zeitschrift fiir Malakozoologie, yr. 8, pp. 17-25, 33-38. MERRIAM, C. W. & E E. TURNER. 1937. The Capay middle Eo- cene of northern California. University of California Publi- cations, Bulletin of the Department of Geological Sciences 24(6):91—114, pls. 5, 6. 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Evolution and classification of the Late Cretaceous-Early Tertiary gastropod Perissitys. Natural History Museum of Los Angeles County, Contri- butions in Science 380:1—37, figs. 1-182. PopENoE, W. P., L. R. SAUL & T. SuSUKI. 1987. Gyrodiform gas- tropods from the Pacific coast Cretaceous and Paleocene. Journal of Paleontology 61(1):70-—100, figs. 1-7. RAFINESQUE, C. S. 1815. Analyse de la Nature, ou Tableau de 1’ Universe est des Corps Organisées. Palermo. 224 pp. RecLuz, C. A. 1842. Description de deux coquilles nouvelles. Revue de Zoologique par la Société de Cuviérienne 5:305— 307. ReEcLuz, C. A. 1850. Notice sur le genre Nérita et sur le S.-G. Neritina, avec le catalogue synonymique des néritines. Jour- nal de Conchyliologie 1:131—164, 277-288. SAuL, L. R. 1983. Turritella zonation across the Cretaceous-Ter- tiary boundary, California. University of California Publi- cations in Geological Sciences 125:1—165, pls. 1-7. SaAuL, L. R. & W. P. PopENoE. 1992. 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Mollusca from the Turritella variata Zone. Pp. 165-232, pls. 18-38 in R. M. Kleinpell & D. W. Weaver, Oligocene Biostratigraphy of the Santa Barbara Embayment, California. University of Cali- fornia Publications in Geological Sciences 43(2): Berkeley, California. Waite, C. A. 1885. On new Cretaceous fossils from California. U.S. Geological Survey Bulletin 22:7—14, pls. 1-5. Wuite, C. A. 1887. Contributions to the paleontology of Brazil; comprising descriptions of Cretaceous invertebrate fossils, mainly from the Provinces of Sergipe, Pernambuco, Para and Bahia. Archivos do Museum Nacional do Rio de Janeiro 7:1—273, pls. 1-28. Woops, A. J.C. & L. R. SAUL. 1986. New Neritidae from south- western North America. Journal of Paleontology 60(3):636— 655, figs. 1-6. WoopDwarbD, B. B. 1892. On the growth and structure of the shell in Velates conoideus, Lamk., and other Neritidae. Proceed- ings of the Zoological Society of London, pp. 528-540. YEN, T. -C. 1946. On Lower Cretaceous fresh-water mollusks of Sage Creek, Wyoming. Notulae Naturae 166:1—13, figs. 1— 4. YEN, T. -C. 1951. Fresh-water mollusks of Cretaceous age from Montana and Wyoming. Part 2. An Upper Cretaceous non- marine molluscan fauna form the Leeds Creek area, Lincoln County, Wyoming. U.S. Geological Survey Professional Pa- per 233-A:11—20, pl. 2. APPENDIX LOCALITIES CITED CAS 183. See LACMIP loc. 6298. LACMIP 6297. In west bank of “‘Big Bend”’ of Cowlitz River, 590 m (1935 ft.) N and 375 m (1230 ft.) W of SE corner of section 28, T. 11 N, R. 2 W, U.S. Geo- logical Survey, 15-minute, Castle Rock Quadrangle, 1953, about 2 km (1.2 mi.) E of Vader, Lewis County, southwestern Washington. Cowlitz Formation. Age: Late middle Eocene (“Tejon Stage’). Collectors: J. L. Goedert, 1982; R. L. Squires, July 13, 1988. LACMIP 6298 [= CAS 183, LACMIP 22536 (= UCLA 2536), UWBM 232, & UWBM 329]. Up-river from LACMIP loc. 6297, in west bank of “Big Bend” of Cowlitz River, 725 m (2378 ft.) N and 285 m (935 ft.) W of SE corner of section 28, T. 11 N, R. 2 W, USS. Geological Survey, 15-minute, Castle Rock Quadran- gle, 1953, about 2 km (1.2 mi.) E of Vader, Lewis County, southwestern Washington. Cowlitz Formation. Age: Late middle Eocene (“Tejon Stage’’). Collectors: Numerous workers over the last 80 years or so. LACMIP 7047. A thin but richly fossiliferous layer of Page 19] limonite-stained white sandstone, 0.9 km (0.75 mi.) east of Lower Lake, 366 m (1200 ft.) S from bridge over Copsey Creek, in gully on W side of creek, SE 1/4 of NE 1/4 of section 11, T. 12 N, R. 7 W, USS. Geological Survey, 7.5-minute, Lower Lake Quadran- gle, 1975, Lake County, northern California. Martinez Formation. Age: Latest early Paleocene or earliest late Paleocene (uppermost ‘“‘unnamed stage’’ or lowermost “Martinez Stage’’). Collectors: D. W. Scharf & W. P. Popenoe, August 26, 1930. LACMIP 9936 [= LACMIP 28787]. Fossiliferous brown sandstone about 4.5 km (2.8 mi.) S of U.S. Highway 26, along west side of Bridge Creek, 610 m (2000 ft.) N and 805 (2640 ft.) E of SW corner of section 25, T. 13 S, R. 27 E, 44°24’34"N, 119°25'10"W, U.S. Geolog- ical Survey, 7.5-minute, Aldrich Mtn. North Quadran- gle, 1972 (photorevised 1983), Grant County, east-cen- tral Oregon. Unnamed strata. Age: Earliest Late Cre- taceous (Cenomanian Stage). Collectors: W. P. Popenoe and J. Alderson, June 12, 1975. LACMIP 10508. At approximately 404 m (1325 ft.) el- evation, just below a coralline-algal interval in limey, muddy siltstone and west of small fault, in roadcout on north side of dirt road, on north slope of Trailer Canyon near top of ridge between Quarry and Trailer canyons, at approximately 50 m east of steel gate at boundary of Topanga State Park, and 4435 m (14,547 ft.) S and 5334 (17,496 ft.) W of NE corner of U.S. Geological Survey, 7.5-minute, Topanga Quadrangle, 1952 (pho- torevised 1981), east-central Santa Monica Mountains, Los Angeles County, southern California. Upper part of Santa Susana Formation. Age: Late Paleocene (“‘Martinez Stage’). Collectors: R. L. Squires and stu- dents, 1997. LACMIP 10676 [= CIT 1559]. Conglomeratic and fos- siliferous outcropping in bed and banks of Los Banos Creek, 823 m (2700 ft.) N and 305 m (1000 ft.) W of SE corner of section 12, T. 11 S, R. 9 E, 36°59'28’N, 120°55'50"W, U.S. Geological Survey, 7.5-minute, Or- tigalita Peak NW Quadrangle, 1969 (photorevised 1984), Merced County, north-central California. Mo- reno Formation, “‘Quinto Shale’? member. Age: Late Cretaceous (Maastrichtian Stage). Collectors: B. C. Adams, R. W. Burger & L. Simon, circa 1942. [Lo- cality is now at damsite of the Los Banos Reservoir. ] LACMIP 10685 [= CIT 1573]. 975 m (3200 ft.) N and 549 m (1800 ft.) W of SE corner of section 12, T. 11 S, R. 9 E, 36°59'03"N, 120°55'58”W, U.S. Geological Survey, 7.5-minute, Ortigalita Peak NW Quadrangle, 1969 (photorevised 1984), Merced County, north-cen- tral California. Moreno Formation, “‘Quinto Shale” member. Age: Late Cretaceous (Maastrichtian Stage). Collectors: B. C. Adams & W. P. Popenoe, 1942. [Lo- cality is now along the eastern side of the Los Banos Reservoir. | LACMIP 22536. See LACMIP 6298. Page 192 LACMIP 23348 [= UCLA 3348]. At elevation of 152 m (S500 ft.), in light gray, fine-grained calcareous ce- mented arkosic sandstone, 30 to 60 cm thick, rich in molluscan fossils, in a small tributary (upper part of Well Canyon), north of Canada Posa, 4325 m (14,190 ft.) N and 1737 m (5700 ft.) W of SE corner of U.S. Geological Survey, 7.5-minute, Santa Cruz Island A Quadrangle, 1943, southwestern Santa Cruz Island, Channel Islands, Santa Barbara County, southern Cal- ifornia. Pozo Formation. Age: Late Paleocene (‘*Mar- tinez Stage’’). Collector: T. Rothwell, February 4, 1955. LACMIP 26720 [= UCLA 6720]. Hill with firebreak, 213 m (700 ft.) E of where 358 m (1175 ft.) contour line crosses Pulga Canyon, just below massive algal lime- stone beds, U.S. Geological Survey, 7.5-minute, To- panga Quadrangle, 1952 (photorevised 1981), Pali- sades Highlands, Santa Monica Mountains, Los An- geles County, southern California. Upper part of Santa Susana Formation. Age: Late Paleocene (‘‘Martinez Stage’’). Collector: J. Alderson, October, 1980. LACMIP 27083 [= UCLA 7083].,.On a NW-facing hill- slope 7.1 km (4.4 mi.) ESE of Punta Rosarito and 0.9 km (0.6 mi.) E of Bahia Sebastian Vizcaino, south- western Baja California Norte Mexico. Sepultura For- mation. Age: Probably late Paleocene (‘Martinez Stage’’). Collector: A. J. C. Woods, circa 1975. The Veliger, Vol. 45, No. 3 of interbedded sandstone and muddy siltstone within a channel complex at the Laurels housing project, 372 m (1220 ft.) N and 665 m (2180 ft.) E of the SW corner of section 17, T. 12 S, R. 3 W, U.S. Geological Survey, 7.5-minute, San Marcos Quadrangle, 1968 (photorevi- sed 1983), Laurels housing development project, west of the city of San Marcos, northern San Diego County, southern California. Santiago Formation. Age: Middle Eocene. Collector: D. J. McGuire, November 30, 1989. SDSNH 4105. From excavation on south side of Califor- nia State Highway 78, in upper part of a medium dark gray, silty, fine-grained sandstone about 2.1 m (7 ft.) thick, about 3 km (1.86 mi.) SE of Sycamore Avenue, city of Vista, U.S. Geological Survey Quadrangle, 7.5- minute, San Marcos Quadrangle, 1968 (photorevised 1983), northern San Diego County, southern Califor- nia. Santiago Formation. Age: Middle Eocene. Collec- tors: B. O. Riney and S. L. Walsh, August 12, 1996. [Excavation has been covered by backfilling of a new concrete retaining wall along south side of freeway. ] UCR 4865. In roadcut on south side of California State Highway 78, 5.2 km (3.2 mi.) SE of city of Vista and 4.8 km NW of city of San Marcos, U.S. Geological Survey Quadrangle, 7.5-minute, San Marcos Quadran- gle, 1968 (photorevised 1983), northern San Diego County, southern California. Santiago Formation. Age: Middle Eocene. Collector: C. R. Givens. SDSNH 3522. At elevation of 174 m (570 ft.), from a temporary excavation of approximately 7.5 m (24.6 ft.) UWBM 232. See LACMIP loc. 6298. UWBM 329. See LACMIP loc. 6298. The Veliger 45(3):193—202 (July 2, 2002) THE VELIGER © CMS, Inc., 2002 Review of the Genus Actinocyclus Ehrenberg, 1831 (Opisthobranchia: Doridoidea) ANGEL VALDES Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, USA; avaldes@nhm.org Abstract. The genus Actinocyclus comprises two species, Actinocyclus verrucosus Ehrenberg, 1831, which is wide- spread through the tropical Indo-Pacific, from the Red Sea to Australia and Hawaii, and Actinocyclus papillatus (Bergh, 1878) known from East Africa, Papua New Guinea, the Philippines, and Japan. These two species are distinguishable by the external morphology and the arrangement and shape of the reproductive organs. There are no major radular differences. The genus name Spaherodoris is a junior synonym of Actinocyclus. Other species names described within these two genera are either junior synonyms of A. verrucosus (Spaherodoris punctata Bergh, 1878, Spaherodoris laevis Bergh, 1890, Spaherodoris japonica Eliot, 1913), synonyms of A. papillatus (Spaherodoris laevis var. variegata Eliot, 1904), or belong to different genera (Actinocyclus fragilis Ehrenberg, 1831, A. velutinus Ehrenberg, 1831). Aldisa nha- trangensis Risbec, 1956, is also a junior synonym of Actinocyclus verrucosus. INTRODUCTION Gosliner & Johnson (1994) studied the phylogenetic re- lationships of the genus Hallaxa Eliot, 1909, and hypoth- esized that Actinocyclus Ehrenberg, 1831, was its sister taxon. According to these authors, Actinocyclus and Hal- laxa are the only two members of the family Actinocy- clidae, which is the sister taxon to the Chromodorididae. At that point, the anatomy of Actinocyclus was known only from drawings of the reproductive system of A. ja- ponicus by Kay & Young (1969) and Gosliner & Johnson (1994), and drawings of several radular teeth by Kay & Young (1969). Up to now, several names have been proposed for spe- cies of this genus, but no one knows for sure how many valid species it comprises. Most authors appear to agree that A. japonicus is the valid name for a widespread Indo- Pacific species (Kay & Young, 1969; Bertsch & Johnson, 1981; Willan & Coleman, 1984; Wells & Bryce, 1993; Gosliner & Johnson, 1994), but its relationships with the type species, A. verrucosus Ehrenberg, 1831, from the Red Sea, are unknown. The position of the Actinocyclidae at the base of the Cryptobranchia makes this group essential for further un- derstanding of the phylogenetic relationships within this diverse clade of dorids. Therefore, a more detailed knowl- edge of the anatomy of this taxon is critical for future research on the phylogeny of the Cryptobranchia. In this paper I attempt a comprehensive anatomical study of the genus Actinocyclus, including features that might be important for future phylogenetic research, such as the central nervous system, the digestive system, and the reproductive system. In addition, a systematic review of all species described is carried out in light of exami- nation of specimens collected from several Indo-Pacific localities, trying to cover the entire geographic range of Actinocyclus. I also attempted to locate in several natural history museums the type material and other historically important specimens of all nominal species involved. The material examined is deposited at the Department of Invertebrate Zoology and Geology of the California Academy of Sciences, San Francisco (CASIZ), the Mu- seum fiir Naturkunde der Humboldt-Universitat zu Berlin (MHUB), the Zoologisk Museum, K@benhavns Univer- sitet, Copenhagen (ZMUC), and the Muséum National d’ Histoire Naturelle, Paris (MNHN). SYSTEMATIC DESCRIPTIONS Genus Actinocyclus Ehrenberg, 1831 Actinocyclus Ehrenberg, 1831: [28]. Type species: Actino- cyclus verrucosus Ehrenberg, 1831, by subsequent des- ignation of J. E. Gray (1847). Sphaerodoris Bergh, 1877:66. Type species: Actinocyclus verrucosus Ehrenberg, 1831, by monotypy. Remarks: Ehrenberg (1831) introduced the new genus Actinocyclus based on two briefly described new species: Actinocyclus verrucosus and A. velutinus. A third species, Actinocyclus fragilis, was included with a question mark. Subsequently, J. E. Gray (1847) selected Actinocyclus verrucosus as the type species of Actinocyclus. Bergh (1877) introduced the new genus Sphaerodoris based on Actinocyclus verrucosus Ehrenberg, 1831, in- cluding two new, not yet described species from the Phil- ippines, and with a question mark “‘Doris incii (Alder)” [Doris incii J. E. Gray in M. E. Gray, 1850 is probably Page 194 The Veliger, Vol. 45, No. 3 a senior synonym of Halgerda willeyi Eliot, 1903 (S. Fah- ey, personal communication)]. Bergh (1877: 66—67) com- mented that Actinocyclus and Sphaerodoris are probably synonyms, but anatomical studies on Actinocyclus would be necessary to confirm this point. Since Actinocyclus was not anatomically studied, Bergh regarded this name as a synonym of Sphaerodoris. These sorts of decisions, which clearly violated the law of priority, were often tak- en by Bergh to suppress poorly described taxa. In any case, Actinocyclus verrucosus is the only valid nominal species originally and without doubt included in the ge- nus Spaherodoris Bergh, 1877, and therefore it is the type species by monotypy. Thus, Spaherodoris is a junior ob- jective synonym of Actinocyclus. Eliot (1913) re-examined the holotype of A. verrucosus and confirmed that it belonged to the same genus as Bergh’s species of Spaherodoris. He also considered that Actinocyclus should be suppressed because of several contradictions between the original description and the actual specimen. On the contrary, O’Donoghue (1929) recognized that Actinocyclus is a valid genus and thus a senior synonym of Spaherodoris.. At the same time, he designated Spaherodoris punctata as the type species of Spaherodoris, but since this species was not included in the original description, such a designation is not valid. Since O’Donoghue’s paper, most authors have accepted the name Actinocyclus as valid, and it is currently in com- mon usage (Kay & Young, 1969; Bertsch & Johnson, 1981; Willan & Coleman, 1984; Wells & Bryce, 1993; Gosliner & Johnson, 1994). Gosliner & Johnson (1994) reviewed the differences between Hallaxa and Actinocyclus. In light of phyloge- netic analysis they concluded that these two genera are clearly distinguishable by the presence of two apomorph- ic features in Actinocyclus: ‘‘an elaboration of the anterior border of the foot and the presence of a secondary am- pulla next to the hermaphroditic duct,’> and one apo- morphic feature in Hallaxa: ‘“‘presence of an elongate prostatic portion of the vas deferens.”’ The present study confirms the presence of the elaboration of the anterior border of the foot and an unusual ampulla in Actinocy- clus. In most groups of dorid nudibranchs the ampulla appears to be a dilatation of the hermaphroditic duct, whereas in species of Actinocyclus it is a lateral expan- sion. Even though the ampulla of Actinocyclus is arranged differently from that of other dorids, it seems to be a homologous structure and the term ‘“‘secondary ampulla”’ appears not to be appropriate. Actinocyclus verrucosus Ehrenberg, 1831 (Figures 1A,B, 2—4) Actinocyclus verrucosus Ehrenberg, 1831:[28—29]. Spaherodoris punctata Bergh, 1877:66 (nomen nudum). Bergh, 1878:587—590, pl. 65, figs 1-5. Spaherodoris laevis Bergh, 1890:925—928, pl. 88, figs 3-12. Figure 1. cosus from Madagascar (CASIZ 073553), photo by T. M. Gos- liner. B. Specimen of A. verrucosus from the Philippines (CASIZ 083843), photo by T. M. Gosliner. C. Specimen of Actinocyclus papillatus from Papua New Guinea (CASIZ 068651), photo by T. M. Gosliner. Living animals. A. Specimen of Actinocyclus verru- Spaherodoris japonica Eliot, 1913:23—26. Aldisa nhatrangensis Risbec, 1956:14—15, pl. 20, fig. 109, pl. 22, upper right figure. Type material: Actinocyclus verrucosus Ehrenberg. Ho- lotype (by monotypy): ““Massaua” = Mits’iwa Island, Ethiopia, dissected (MHUB 594). Spaherodoris punctata Bergh. Holotype (by monoty- A. Valdés, 2002 Page 195 Figure 2. Actinocyclus verrucosus, scanning electron micrographs. A. Dorsal tubercle (CASIZ 099250), scale bar = 600 pm. B. Gill (CASIZ 086635), scale bar = 1.5 mm. C..Jaw elements (CASIZ 073553), scale bar = 15 ym. Abbreviations: a, anus opening; r, renal opening. py): “Lapinig” probably Lapinin Island, Northwest of Bohol Island, Philippines, dissected (ZMUC GAS-2118). Aldisa nhatrangensis Risbec. Holotype (by original designation): Hon Lon, Nha Trang, Vietnam, dissected (MNHN). The type material of Spaherodoris laevis Bergh, and Spaherodoris japonica Eliot, is probably lost. No speci- mens are deposited at the Zoologisk Museum, Kgbenhavns Universitet, Copenhagen (K. Jensen, person- al communication) or The Natural History Museum, Lon- don (A. Campbell, personal communication). Additional material: South of Soanambo Hotel, [le Saint Marie, Madagascar, 6 April 1990, 1 specimen 18 mm preserved length, collected by T; M. Gosliner (CASIZ 073553). Devil’s Point, southwest side of Maricaban Is- land, Batangas, Luzon, Philippines, 19 February 1992, 1 specimen 21 mm preserved length, collected by T. M. Gosliner (CASIZ 083843); 19 February 1992, 1 specimen 39 mm preserved length, collected by T. M. Gosliner (CASIZ 083793); 17 March 1994, 1 specimen 20 mm preserved length, 24 m depth, collected by T. M. Gosliner (CASIZ 096290); 15 April 1996, 2 specimens 21 and 23 mm preserved length, 20 m depth, collected by T. M. Gosliner (CASIZ 106456). Okinawa, Ryukyu Islands, Ja- pan, 2 May 1992, 1 specimen 23 mm long, dissected, collected by R. Bolland (CASIZ 086635). Tengan Pier, 14 km West of [kei-shima, Okinawa, Ryukyu Islands, Ja- pan, 9 April 1994, 1 specimen 35 mm preserved length, 12 m depth, dissected, collected by R. Bolland (CASIZ 099250), 18 October 1994, 1 specimen 33 mm preserved length, 12 m depth, collected by R. Bolland (CASIZ 104697). O Ennubuj, Kwajalein Atoll, Marshall Islands, 6 December 1992, 1 specimen 24 mm preserved length, 6 m depth, collected by S. Johnson (CASIZ 116662). Makua, Oahu Island, Hawaii, 17 April 1985, 1 specimen 12 mm preserved length, 5 m depth, collected by S. John- son (CASIZ 116894). Geographic range: This species is known from the Red Sea (Ehrenberg, 1831), East Africa (Eliot, 1904), Viet- nam (Risbec, 1956), Japan (Eliot, 1913), the Philippines (Bergh, 1878), Indonesia (Bergh, 1890), Malaysia (Eliot, 1904), Western Australia (Wells & Bryce, 1993), Queens- land (Willan & Coleman, 1984), and Hawaii (Kay & Young, 1969). The present paper reports the first records from Madagascar and the Marshall Islands. External morphology: The body is elevated, short, oval, almost as long as wide (Figures 1A, B). The dorsum is Page 196 The Veliger, Vol. 45, No. 3 covered with several simple conical tubercles scattered irregularly. Some of them are much larger and have a depression on the apex (Figure 2A). The central part of the body is clearly elevated over the mantle margin, which is relatively narrow. The perfoliate rhinophores are composed of 20 lamellae in a 33 mm-long specimen (CASIZ 104697). There are 16 unipinnate branchial leaves in the 33 mm-long specimen (Figure 2B). In the living animal they are pointing inward, with the apices very close to each other. The background color varies from cream brownish to dark brown or gray (Figure 1B). Some specimens are al- most black (Figure 1A). There are paler areas, generally white or yellowish, irregularly distributed on the dorsum. The entire dorsum is covered with small, evenly distrib- uted black spots. The depressions on the tips of the larger tubercles are dark brown or black. The gill is dark gray or black, with numerous small white spots, more densely distributed near the base. The rhinophores are the same color as the body. The anterior border of the foot is not grooved or notched, with anteriorly directed foot margins partially surrounding the mouth area (Figure 3F). There are no oral tentacles. Anatomy: The posterior end of the glandular portion of the oral tube has two strong retractor muscles (Figure 3D) which attach to the body wall. The oval, muscular buccal bulb has four additional muscles attached. Two long sal- ivary glands connect with the buccal bulb at the sides of the esophageal junction. The buccal bulb is as long as the glandular portion of the oral tube. The jaws are composed of numerous undivided rodlets (Figure 2C). The radular formula is 65 X 15.0.15 in a 35 mm-preserved-length specimen (CASIZ 099250) and 70 X 21.0.21 ina 18 mm- preserved-length specimen (CASIZ 073553). Rachidian teeth are absent. The innermost lateral teeth are broad and thick (Figures 4A, B). They have a large rounded cusp and bear six to seven denticles along their inner edge. The mid-lateral teeth are narrow basally and elongated (Figure 4C). The outermost teeth are shorter than the mid- laterals (Figure 4D). The outer laterals bear 13-17 den- ticles along their inner margin. The esophagus is short and convoluted and connects with the digestive gland. The narrow hermaphroditic duct expands into the elon- gate and convoluted ampulla, which inserts distally at the junction of the oviduct and the prostate (Figures 3B, C). The oviduct enters the female gland in the center of the mass. The prostate is rounded, as long as wide, and gran- ular. It connects with a long duct that narrows and ex- pands again into the short ejaculatory portion of the def- erent duct. The muscular ejaculatory portion opens into a common atrium with the vagina. The penis is unarmed. The vagina is very long and undulate. Near its proximal end it joins the pyriform seminal receptacle, the uterine duct, and the oval bursa copulatrix. Both the bursa co- pulatrix and seminal receptacle are stalked. The bursa co- pulatrix is about twice as large as the seminal receptacle (Figure 3C). In the central nervous system (Figure 3E) the cerebral and pleural ganglia are partially fused and distinct from the pedal ganglia. There is a separate abdominal ganglion on the right side of the visceral loop. Paired gastroesoph- ageal, rhinophoral, and optical ganglia are also present. The pedal ganglia are clearly separated. The pedal and parapedal commissures are fused together. The circulatory system (Figure 3A) consists of a large heart and a single blood gland situated over the central nervous system. Remarks: The original description of Actinocyclus ver- rucosus 1s a brief Latin text with no illustrations or ana- tomical information (Ehrenberg, 1831). The re-examina- tion of the holotype of this species, collected Mits’iwa Island, Ethiopia, confirmed that its identity agrees with the usage of the name Actinocyclus. The specimen was dissected by Eliot during the preparation of his 1913 pa- per, the radula is missing, and the reproductive system is damaged. Yet, the external morphology is identical to that of our specimens. Bergh (1877) introduced for the first time the name Spaherodoris punctata, but without description, and therefore it is a nomen nudum. Later, Bergh (1878) de- scribed this species based on preserved specimens from the Philippines. It is not possible to confirm their identity based on the original description of the external mor- phology; however, re-examination of the type material confirms that it is conspecific with Actinocyclus verru- cosus. The 38 mm-long holotype of this species has the dorsum covered with a few conical tubercles and 21 un- ipinnate branchial leaves. Spaherodoris laevis was described by Bergh (1890) on the basis of a single specimen collected from Ambon, Indonesia. The preserved animal was described as being uniformly brown or olive gray with some yellowish areas on the dorsum. As described, the radula and reproductive system are identical to those of Actinocyclus verrucosus. Unfortunately, the holotype of this species in untraceable, and this synonymy is based on review of the original description. Eliot (1913) described the new species Spaherodoris japonica, from Japan, which, in his opinion, might be conspecific with A. verrucosus. According to Eliot (1913), the main difference between S. japonica and other species of the genus is that both rhinophores open in the same cavity. However, Eliot recognized that this could be a teratology. He did not find other differences between both species that could justify the separation of A. japon- icus. Kay & Young (1969) redescribed A. japonicus from Hawaii, and regarded Aldisa nhatrangensis Risbec, 1956, A. Valdés, 2002 Page 197 ——| Figure 3. Actinocyclus verrucosus, anatomy of a specimen from Japan (CASIZ 099250). A. General view of the anatomy, scale bar = 1 mm. B. Reproductive system, scale bar = 1 mm. C. Detail of several reproductive organs, scale bar = 1 mm. D. Dorsal view of the buccal bulb, scale bar = 1 mm. E. Central nervous system, scale bar = 0.5 mm. E Ventral view of the mouth area, scale bar = | mm. Abbreviations: a, ampulla; ag, abdominal ganglion; bl, blood gland; bc, bursa copulatrix; bg, buccal ganglion; c, cerebral nerves; cg, cerebral ganglion; dd, deferent duct; es, esophagus; f, female glands; g, genital nerve; h, digestive gland; ht, heart; i, intestine; m, retractor muscles; ot, oral tube; p, pedal nerves; pl, pleural nerves; plg, pleural ganglion; pr, prostate; sg, salivary gland; sp, syrinx; rs, radular sac; sr, seminal receptacle; v, vagina; vl, visceral loop. Page 198 The Veliger, Vol. 45, No. 3 Figure 4. Actinocyclus verrucosus, scanning electron micrographs of the radula. A. Innermost lateral teeth of a specimen from Japan (CASIZ 099250), scale bar = 30 um. B. Innermost lateral teeth of a specimen from Madagascar (CASIZ 073553), scale bar = 25 wm. C. Mid-lateral teeth of a specimen from Japan (CASIZ 099250), scale bar = 30 pm. D. Outermost lateral teeth of a specimen from Japan (CASIZ 099250), scale bar = 30 pm. A. Valdés, 2002 as a synonym. The radula and reproductive system are identical to those of our specimens. After the examination of the type material of several species and additional specimens from Japan, the Phil- ippines, Hawaii, and Madagascar, it is clear that Actino- cyclus verrucosus 1s a widespread species in the tropical Indo-Pacific that exhibits wide variation in color, but also a great consistency in reproductive and radular features among different specimens. There are two other species that were assigned to the genus Actinocyclus by Ehrenberg (1831), Actinocyclus fragilis Ehrenberg, 1831, and A. velutinus Ehrenberg, 1831. Both Bergh (1877) and O’Donoghue (1929) re- garded them as unrecognizable. A re-examination of the original description of these taxa reveals that they do not belong to the genus Actinocyclus in the sense of its pre- sent usage. The dorsum of A. velutinus is covered with “very densely arranged minute hairs” (probably cary- ophyllidia), and A. fragilis is a large, yellowish brown species with densely arranged marginal dark spots and numerous dorsal tubercles. Actinocyclus papillatus (Bergh, 1878) (Figures 1C, 5,6) Sphaerodoris papillata Bergh, 1877:66 (nomen nudum). Bergh, 1878:590—592, pl. 66, figs 6,7. Sphaerodoris laevis var. variegata Eliot, 1904:403—404. Type material: Spaherodoris papillata Bergh. Holotype (by monotypy): Ubay, Northwest of Bohol Island, Phil- ippines, dissected (ZMUC GAS-2119). The holotype of Spaherodoris laevis vat. variegata is probably lost. It could not be located in the collections of The Natural History Museum, London (A. Campbell, personal com- munication). Additional material: Barracuda Point, east side of Pig Island, near Madang, Papua New Guinea, 11 August 1989, 30 m depth, 1 specimen 35 mm preserved length, collected by M. Ghiselin (CASIZ 068651). Geographic range: So far this species is known only from the east coast of Africa (Eliot, 1904), Japan (Hori & Fukuda, 1996), the Philippines (Bergh, 1878), and Pap- ua New Guinea (this paper). External morphology: The body is elevated, short and oval (Figure 1C). The dorsum is covered with numerous simple conical to rounded tubercles scattered irregularly. The tubercles situated on the center of the dorsum and near the gill opening are larger than the others. The cen- tral part of the body is clearly elevated over the mantle margin, which is relatively narrow. The perfoliate rhin- ophores are composed of 22 lamellae. There are 14 uni- pinnate branchial leaves in the 35 mm-preserved-length specimen. In the living animal they are pointing inward, with the apices very close to each other. Page 199 — Figure 5. Actinocyclus papillatus (CASIZ 068651). A. Repro- ductive system, scale bar = 1 mm. B. Ventral view of the mouth area, scale bar = 1 mm. Abbreviations: a, ampulla; bc, bursa copulatrix; dd, deferent duct; f, female glands; pr, prostate; sr, seminal receptacle; v, vagina. The background color is reddish cream (Figure IC). The entire dorsum is covered with a number of short, irregular, very densely arranged dark gray lines. Most of the lines are ramified into irregular branches. There are also irregular white areas, composed of the aggregation of numerous opaque white spots. The tubercles are pale brown or ochre, with the apex darker. A pale brown or ochre irregular line surrounds the mantle margin. The gill and rhinophores are pale brown to cream. The branchial leaves are covered with numerous minute white dots. The anterior border of the foot is not grooved or notched, with anteriorly directed foot margins partially surrounding the mouth area (Figure 5B). There are no oral tentacles. Anatomy: The jaws are composed of numerous, long un- divided rodlets (Figure 6D). The radular formula is 69 29.0.29 in the 35 mm-preserved-length specimen (CASIZ 068651). Rachidian teeth are absent. The innermost lat- eral teeth are broad and elongate (Figure 6A). They have Page 200 itn) : = <= a very short and wide rounded cusp and six to eight elon- gate denticles along their inner edge. The mid-lateral teeth have a narrow base and are elongated (Figure 6B). They are also multidenticulated, with 12—16 long denti- cles. The outermost teeth are shorter than the mid-laterals, hs Figure 6. Actinocyclus papillatus (CASIZ 068651), scanning electron micrographs. A. Innermost lateral teeth, scale bar = 35 ym. B. Mid-lateral teeth, scale bar = 35 jum. C. Outermost lateral teeth, scale bar = 40 pm. D. Jaw elements, scale bar = 10 wm. The Veliger, Vol. 45, No. 3 but very similar in shape (Figure 6C). The outer laterals have 12-16 denticles along their inner margin. The narrow hermaphroditic duct expands into the large ampulla, which inserts distally at the junction of the ovi- duct and the prostate (Figure 5A). The oviduct enters the A. Valdés, 2002 female gland in the center of the mass. The prostate is oval, almost as long as wide, and granular. It connects with a long duct that narrows and expands again into the short ejaculatory portion of the deferent duct. The mus- cular ejaculatory portion opens into a common atrium with the vagina. The penis is unarmed. The vagina is very long and undulate. Near its proximal end it joins the elon- gate seminal receptacle, the uterine duct, and the rounded bursa copulatrix. The bursa copulatrix is stalked. Remarks: Bergh (1877) first introduced the name Spah- erodoris papillata, but without a description, and there- fore it is a nomen nudum as of that paper. Later, Bergh (1878) described the species based on preserved speci- mens from the Philippines. Examination of the holotype revealed that the dorsum of this species is covered with numerous simple conical to rounded tubercles. The 48 mm-long specimen has 17 unipinnate branchial leaves. The features of this specimen fit with those of the spec- imen from Papua New Guinea here examined, and they are clearly conspecific. Eliot (1904) described Spaherodoris laevis var. varie- gata based on a single specimen collected from Mnemba Island, Zanzibar, East Africa. The 31 mm-long animal was collected while laying a light violet-colored egg mass and had 14 branchial leaves. The color of the living an- imal was described as dark brown with greenish and sandy patches. The preserved specimen was mottled brown of darker and lighter shades and had bands formed of minute black spots, arranged in an irregular pattern, particularly near the branchial opening. Eliot (1904) de- scribed the dorsum of this species as having “irregular excrescences which resemble a marine growth.”’ The rad- ula had a formula 70 X 25.0.25. Eliot (1904) compared this animal to other specimens from Malaysia, “‘appar- ently referable to S. laevis [= Actinocyclus verrucosus],” which had the dorsum ‘“‘quite smooth and of an almost uniform bluish-olive colour.” In the same paper, he also mentioned another specimen collected from Mombasa, Kenya, which was different in color, but cannot be iden- tified with certainty from the short description. Eliot’s (1904) description of Spaherodoris laevis var. variegata fits with the characteristics of the holotype of Spaherodoris papillata as well as with those of the spec- imen from Papua New Guinea. The brownish external color with irregular black lines, the number of branchial leaves, the abundance of large dorsal tubercles, and the radula formula are very similar. Actinocyclus papillatus appears to be a different spe- cies from A. verrucosus. Externally, A. papillatus has more and larger tubercles than A. verrucosus. Also it has a number of ramified black lines on the dorsum that are absent in all specimens examined of A. verrucosus. Two specimens of A. papillatus (32 and 35 mm preserved length) have 14 branchial leaves, and one specimen 48 mm preserved length has 17 (Eliot, 1904; present paper), Page 201 whereas smaller specimens of A. verrucosus (21 mm pre- served length) have 16. A 38 mm-preserved-length spec- imen of A. verrucosus has 21 branchial leaves. Also, the gill of A. papillatus is pale brown or cream in color, whereas it is dark gray or black in A. verrucosus. In the reproductive system, the seminal receptacle of A. papil- latus is more elongate than that of A. verrucosus. In ad- dition, the ampulla and the prostate seem to be larger in A. papillatus. The radula of A. papillatus has more lateral teeth than that of A. verrucosus, for a specimen smaller in size. Eliot (1904) found a formula of 70 X 25.0.25 for a 31 mm-preserved-length specimen, the formula of the 35 mm-preserved-length specimen from Papua New Guinea is 69 X 29.0.29, whereas it is 65 4000 m) where most are very sparsely distributed, and sam- pling has been limited. In this paper, we analyze geo- graphic variation in shell form of a common and broadly distributed abyssal snail Xyloskenea naticiformis (Jef- freys, 1883), collected from the North American Basin of the Atlantic Ocean. Patterns of geographic variation in X. naticiformis provide information of basic interest on pop- ulation differentiation in abyssal species. ' Corresponding author, e-mail: michael.rex@umb.edu * Current address: 15017 Good Meadow Court, Gaithesburg, Maryland 20878, USA MATERIALS AND METHODS Xyloskenea naticiformis is a minute trochiform archaeo- gastropod belonging to the family Skeneidae (Warén, 1996). It is widespread at abyssal and bathyal depths of the Atlantic (Warén 1996) and is the second most abun- dant gastropod species at abyssal depths in the North At- lantic Basin (Rex & Warén, 1982). As with most deep- sea species, little is known of its natural history. The lar- val shell consists of a single simple whorl measuring 250 zm in maximum diameter (Figure 1). This indicates a non-planktotrophic mode of development (Bouchet & Warén, 1994). Whether or not there is a non-feeding pe- lagic dispersal stage cannot be determined from larval shell morphology in archaeogastropods (Hadfield & Strathmann, 1990). The broad distributions of many deep- sea archaeogastropods and their frequent association with ephemeral patchy habitats (McLean, 1992; Warén & Bouchet, 1993; Warén, 1996; Marshall, 1994) would seem to require dispersal, which in cold bottom currents could involve considerable distances (Hoegh-Guldberg et al., 1991; Shilling & Manahan 1991; Welborn & Mana- han, 1991). In every case where a substrate is known, members of the genus Xyloskenea in the deep sea are associated with sunken wood (Warén, 1996). There is no record of wood occurring in the samples analyzed here, but this could easily represent a sampling bias. The rel- atively high abundance and consistent occurrence of X. naticiformis in abyssal samples from the western North Atlantic suggest that it might be a facultative deposit feeder as well as grazing on plant debris. M. A. Rex et al., 2002 Page 219 Figure 1. Apical view of a specimen of Xyloskenea naticiformis from station 124 (see Table 1 for station data). The arrow indi- cates the terminus of the larval shell. The larval shell measures 250 wm in maximum width, and the adult shell 1.66 mm in maximum width. We measured shell form of 152 specimens of Xylos- kenea naticiformis collected with an epibenthic sled (Hes- sler & Sanders, 1967) from eight sampling stations in the western North Atlantic (Table 1, Figure 2). One station (85) is located at 3834 m on the lower continental rise, and the other seven are abyssal (4680—4862 m). Our se- lection criterion was simply to measure all available spec- imens in sufficiently good condition for samples with = nine such individuals (X. naticiformis appeared in seven other samples in this depth range, but with only one to two individuals per sample, which does not permit statis- tical comparison). The distribution of samples allows us to examine geographic variation in shell form over hori- zontal scales of up to 100s of kilometers (4—483 km) and bathymetric scales up to about 1000 m (1—1028 m). In our earlier analyses of geographic variation in deep- sea snails, e.g., Rex et al., 1988; Rex & Etter, 1990 we quantified shell form using an approach developed by Gould (1969) in which shell size, shape, and sculpture are standardized to common growth stages. These stan- dardized measurements were referenced to the terminus of the protoconch which marks the transition from larval to adult growth. These analyses were conducted on ris- soids and turrids which have relatively high-spired shells so that much of each whorl is exposed for taking mea- surements. The shells of Xyloskenea naticiformis require a different approach. They lack conspicuous sculpture and are much more globular so that early whorls are more obscured by subsequent growth (Figures 1 and 3). Also, in larger specimens, corrosion often makes the adult-lar- val transition difficult or impossible to discern so that accurate measurements cannot be taken at common growth stages on the adult shell. However, the simple unadorned shells of Xyloskenea naticiformis can be used to estimate Raup’s (1966) basic parameters of shell geometry. To measure these parame- ters we made camera lucida drawings of the shells (at x50) in two orientations (Figure 3). Following Raup (1966) and Newkirk & Doyle (1975), we approximated the four basic parameters of shell form using the mea- surements indicated in Figure 3: (S) Shape of the Generating Curve. This is expressed as a ratio of the width of the aperture to the height of the aperture. (W) Rate of Whorl Expansion. Raup (1966) defined this as: 27/0 ro w=(2 Tee where r, and r, are radii from the axis of coiling to corresponding points on the generating curve (in this case the outer margin of whorls) separated by an angular distance of 0 radians. We measured radii (OS and OE in Figure 3) every 45°, so the appro- priate exponent (2717/8) is eight. Estimates of W were averaged for each individual (mean = 14, range 8— 17 values). (D) Position of the Generating Curve in Relation to the Coiling Axis. In most prosobranchs the whorls are wound tightly with the inner margins in contact so that D is zero. In umbilicate snails like Xyloskenea naticiformis, D is the rate at which whorls move away from the axis of coiling, creating a cone- shaped opening that extends from the bottom of the shell toward the apex. D is the ratio of the radius at the inner margin of the whorl to that at the outer margin. Again these ratios were measured every 45° and averaged (mean = 15, range 9-18 values). (T) Rate of Translation. This is the rate at which whorls move down the axis of coiling in helicoid shells. Raup (1966) defined it as dy/dr, where dy is the distance which the center of the generating curve moves down the coiling axis, and dr is the distance which it moves away from the axis. Since it is dif- ficult to locate the center of the generating curve of successive whorls, we followed Newkirk & Doyle (1975) in approximating T as the ratio of height of the axis of coiling to the radius (Figure 3). Averages and standard deviations for S, W, D, and T in all eight populations are given in Table 1. We performed an ANOVA and Sheffé multiple com- parisons among stations for all four variables to test the null hypothesis of no difference in shell form among pop- ulations. To get a more general composite picture of in- terpopulation differentiation, we combined all four pa- rameters of shell geometry into a single measure of phe- notypic similarity by using a quantified Jaccard’s Coef- ficient (Sepkoski, 1974) calculated on the average values Page 220 42° 40° S8r 36° 34° K Sen 4000 30° 78° 76° 74° Ve The Veliger, Vol. 45, No. 3 rm (ee 9 S = i > S N ID \ ae 1Or 68° 66° 64° 62° Figure 2. Map of deep-sea benthic stations where samples of Xyloskenea naticiformis analyzed in this study were collected. See Table 1 for station data. shown in Table |. To assess whether the degree of phe- notypic difference among populations corresponds to the degree of geographic separation, we carried out a multiple regression with Jaccard’s Coefficient as the response var- iable, and depth difference and horizontal distance apart as explanatory variables. RESULTS Anp DISCUSSION Mean values for the four variables of shell form are pre- sented in Table 1. Shells from all localities have very similar generating curves (width to height ratios of ap- ertures are close to one, Table 1). However, shells from station 85 (at 3834 m) stand out as being uniquely dif- ferent from all abyssal populations in having a more glob- ular shape: translation rates are lower and whorl expan- sion rates are higher. Values of D are also lower in station 85, 1.e., the umbilicus is relatively less well developed because of the higher rate of whorl expansion. The AN- OVA reveals a weak overall difference in S, and highly significant differences among samples for the other three M. A. Rex et al., 2002 S=(awmn) W=(08/66)> D=(50/58) T=(or/58) height =Op width=ao0s Zeos=45° Figure 3. Apical and apertural views of Xyloskenea naticiformis showing the measurements taken to estimate Raup’s (1966) four basic parameters of shell geometry. See text for an explanation of the variables and how shells were measured. variables (Table 2). Multiple comparison tests show that these differences are largely attributable to station 85 which differs from selected abyssal stations in the same directions noted above (Table 2). Phenotypic similarity measured as the quantified Jac- card’s Coefficient is significantly and negatively correlat- ed with depth differences among samples (r = —0.44, F, 5, = 6.283, P = 0.019) due to the distinctiveness of the population from station 85 and the large depth sepa- Page 221 Table 2 ANOVA with multiple comparisons for Raup’s (1966) four basic parameters of shell geometry (S, W, D, T) for pop- ulations of Xyloskenea naticiformis in the western North Atlantic. See Table 1 for station data. The inequality signs for the multiple comparison tests indicate a significant (P < 0.05) difference and the direction of the difference. Multiple Variable df F Significance comparison S 7,144 2.210 P = 0.0367 W 7,144 3.524 P = 0.0016 5) = 11721 D 7,144 3.892 P = 0.0006 85 < 84 T 7,144 3.489 P = 0.0017 85 < 123 ration (~800—1000 m) between station 85 and abyssal stations. The degree of phenotypic similarity is unrelated to horizontal separation (F,,, = 3.785, P = 0.063). A multiple regression with both distance and depth included as explanatory variables is marginally significant (F,>5) = 3.56, P = 0.044). When the ANOVA is performed on only abyssal sta- tions, differentiation among samples is still detectable, but at a lower level of statistical significance. Translation rate no longer varies significantly (F,).;5 = 1.925, P = 0.082). The parameters S, W, and D show significant var- iation among samples (P = 0.028, 0.008, and 0.017, re- spectively) with multiple comparison tests detecting a dif- ference in only one case (for W, 121 < 124). For abyssal samples, the degree of phenotypic similarity is not related significantly to either depth difference (F,,, = 0.424, n.s.), or distance apart (F,,;, = 0.433, n.s.). A multiple regression analysis using both depth difference and dis- tance is not significant (F,,, = 1.518, n.s.). In summary, the clearest divergence in shell form is associated with the large bathymetric difference (800— 1000 m) between station 85 on the continental rise and Table 1 Station data, sample size (n), and the means (x) and standard deviations (SD) of Raup’s (1966) four basic parameters of shell geometry (S, W, D, T) for populations of Xyloskenea naticiformis examined in this study. See Figure 2 for a map of station localities. See the text and Figure 3 for a description of the variables and their measurement. Depth Latitude Longitude : seas Aaa ws ate ee eee Z Station (m) (N) (W) n X (SD) XG (SD) BG (SD) Xx (SD) 85 3834 SSD 69°26.2' 20 0.985 (0.048) 2.285 (0.221) 0.416 (0.032) 0.794 (0.085) 70 4680 36°23.1' 67°58.0' 14 0.976 (0.076) 2.210 (0.107) 0.434 (0.013) 0.833 (0.062) 84 4749 36°24.4' 67°56.0' 30 0.971 (0.059) 2.160 (0.138) 0.442 (0.016) 0.869 (0.078) 109 4750 36°25.0' 68°06.0' 9 1.001 (0.089) 2.158 (0.053) 0.424 (0.017) 0.876 (0.074) 121 4800 35°50.0' 65°11.0' 12 0.963 (0.071) 2.053 (0.102) 0.438 (0.015) 0.838 (0.130) 125 4825 37°25.0' 65°52.0’ 35 0.978 (0.044) 2.190 (0.160) 0.430 (0.018) 0.861 (0.063) 123 4853 37°29.0' 64°14.0' IS) 1.025 (0.056) DATS (0.106) 0.429 (0.011) 0.912 (0.066) 124 4862 37°25.0' 63°58.0' 17 1.014 (0.062) 2.244 (0.095) 0.439 (0.017) 0.839 (0.073) Page 222 the Veliger, Vol 45, Nows the abyssal stations. The degree of horizontal separation seems unrelated to phenotypic divergence. A lesser de- gree of differentiation occurs among abyssal samples, and it does not appear to correspond in any consistent way to either depth or horizontal separation. Overall, the geo- graphic variation in shell geometry observed is too idi- osyncratic and subtle to warrant speculation about its po- tential adaptive significance. Also, it is important to rec- ognize that we cannot determine the degree to which it represents selection or phenotypic plasticity (Trussell, 1996). The most significant finding is that X. naticiformis shows only very modest geographic variation, particular- ly among abyssal populations, on quite large geographic scales. Both the relative degree of geographic differentiation in Xyloskenea naticiformis and its association with depth rather than horizontal separation accord well with the overall trend in geographic variation observed in other deep-sea prosobranchs of the western North Atlantic (Rex et al., 1988: Rex & Etter, 1990; Etter & Rex, 1990). In- traspecific differentiation in shell form measured as Ma- halanobis’ generalized distance (D?) is highest on the up- per continental slope and decreases with increasing depth to the abyssal plain (Etter & Rex, 1990). Size-depth clines in gastropod shells also become less pronounced with in- creasing depth (Rex & Etter, 1998). Geographic variation in deep-sea species appears to be less well developed than coastal snails show, even on much smaller geographic scales—though most studies of form in shallow-water species focus on a single taxon, the littorinids (cf., e.g., Newkirk & Doyle, 1975; Johan- nesson 1986; Grahame et al., 1990). Within the deep sea, differentiation tends to be more associated with depth than with horizontal separation (Rex et al., 1988; Rex & Etter, 1990; France & Kocher, 1996). The rate of faunal replacement with depth in snails decreases with increas- ing depth (Rex, 1977, 1981), and is highly correlated with phenotypic divergence among samples (Etter & Rex, 1990). Both phenotypic change within species and the rate of species turnover reflect the steepness of the en- vironmental gradient which appears to parallel the depth gradient, at least for prosobranchs in the deep western North Atlantic. In contrast to the bathyal environment, the abyssal plain seems to be characterized by a monot- onous assemblage of snails and little intraspecific geo- graphic variation in shell architecture on regional spatial scales. Findings presented here for Xyloskenea naticifor- mis Support the theory that the abyss is less conducive than the bathyal zone to population differentiation in gas- tropods of the western North Atlantic (Etter & Rex, 1990; Rex & Etter, 1998). Acknowledgments. We thank Jack Cook for the map of the western North Atlantic, and Mary Smith for the SEM used in Figure 1. Howard Sanders provided the material on which this analysis is based. Maria Papuga helped prepare the manuscript. This research was supported by the National Science Foundation Grant OCE-9301687 to MAR, and by the University of Massa- chusetts. LITERATURE CITED BoucuHeET, P. & A. WAREN. 1994. Ontogenetic migration and dis- persal of deep-sea gastropod larvae. Pp. 98-117 in C. M. Young & K. J. Eckelbarger (eds.), Reproduction, Larval Bi- ology, and Recruitment of the Deep-Sea Benthos. Columbia University Press: New York. CHASE, M. R., R. J. Errer, M. A. REx & J. M. Quattro. 1998. Bathymetric patterns of genetic variation in a deep-sea pro- tobranch bivalve, Deminucula atacellana. Marine Biology 131:301—308. Etter, R. J. & J. EF Grasse. 1992. Patterns of species diversity in the deep sea as a function of sediment particle size di- versity. Nature 360:576—578. Erter, R. J. & L. S. 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The number of sperm delivered is an important determinant for achieving fertilization in sperm competition. Hermaphroditic gastropods with short mating intervals may deplete their autosperm reserves. An earlier study showed that individuals of the simultaneously hermaphroditic land snail Arianta arbustorum need at least 8 days to replenish their autosperm reserves after a successful copulation, and that the number of sperm transferred in the second copulation slightly increased up to an intermating interval of 4 weeks. We compared spermatophore size, number of sperm delivered, and mating behavior in snails with longer intermating intervals. Snails that remated after 7-8 weeks did not differ in spermatophore size and number of sperm transferred from individuals that remated after 3-4 weeks. The number of sperm delivered averaged 2,151,000 in the first copulation and 2,130,000 in the second copulation. Snails with a longer intermating interval showed a shorter courtship, but did not differ in copulation duration from snails which remated after 3—4 weeks. Furthermore, different intermating intervals did not affect female fecundity (number of eggs produced and hatching success of eggs). These results indicate that A. arbustorum entirely replenishes its autosperm reserves within 3-4 weeks after a successful copulation. INTRODUCTION Pulmonate land snails are simultaneous hermaphrodites with internal fertilization. Individuals of a variety of spe- cies mate with two or more different partners in the course of a reproductive season and store foreign sperm for long periods. Promiscuous mating and sperm storage are a prerequisite for sperm competition, i.e., the com- petition between spermatozoa from two or more males to fertilize the eggs of a single female (Parker, 1970). Sperm competition might significantly affect the reproductive bi- ology of pulmonate land snails. However, with a few ex- ceptions, evolutionary and behavioral aspects of sperm competition have not been examined in terrestrial gastro- pods (Baur, 1998). Multiple mating is common in helicid snails. Individ- uals of Helix pomatia (Linnaeus, 1758), Cepaea nemor- alis (Linnaeus, 1758), and Arianta arbustorum (Linnaeus, 1758) have been observed to mate repeatedly with dif- ferent partners in the course of a reproductive season, resulting in multiple-sired broods (Wolda, 1963; Murray, 1964; Baur, 1988). Helix pomatia copulated two to six times per year in a Danish population (Lind, 1988), two to four times in a German population (Tischler, 1973), and H. aspersa on average three times (maximum seven times) in a British population (Fearnley, 1993, 1996). Pa- ternity analysis in egg batches of A. arbustorum indicated ' Corresponding author, e-mail: Bruno.Baur@unibas.ch that at least 63% of the snails used sperm from two or more mates for the fertilization of their eggs (Baur, 1994). The few data available on mating frequency in gastro- pods suggest that terrestrial gastropods copulate less fre- quently than freshwater and marine gastropods (Baur, 1998). In intertidal and terrestrial gastropods, the repro- ductive activity is limited by favorable environmental conditions (the high risk of desiccation may incur a sig- nificant cost of mating). Other explanations for the rela- tively small number of copulations in terrestrial pulmo- nates include the cost of mucus production during mating, spermatophore production (in some species), as well as the large number of sperm delivered during a copulation which may result in sperm depletion. A previous study showed that individuals of A. arbustorum needed at least 8 days to replenish their sperm reserves after a successful copulation (Locher & Baur, 1999). Furthermore, the num- ber of sperm delivered in the second copulation increased with an increasing intermating interval from 6 to 29 days. This finding suggests that the number of sperm delivered increases with even longer intermating interval. The pre- sent study examines this idea. Arianta arbustorum is a simultaneously hermaphroditic land snail common in moist habitats of northwestern and central Europe. The snail has determinate growth (shell breadth of adults 17—22 mm); individuals become sexu- ally mature at an age of 2—4 years, and adults live another 3—4 years (maximum 14 years; Baur & Raboud, 1988). In the field, snails deposit one to three egg batches con- sisting of 20-50 eggs, per reproductive season (Baur & C. Hanggi et al., 2002 Raboud, 1988; Baur, 1990). Breeding experiments showed that 12 of 44 virgin individuals (27%) prevented from mating produced a few hatchlings by self-fertiliza- tion in the second and third years of isolation (Chen, 1993). The reproductive success of selfing individuals, however, was less than 2% of that of mated snails, sug- gesting high costs for selfing (Chen, 1994). Mating behavior in A. arbustorum includes elaborate courtship behavior with optional dart shooting, i.e., the pushing of a calcareous dart into the mating partner’s body), and lasts 2-18 hr (Hofmann, 1923; Baur, 1992a). Copulation is reciprocal; after intromission each snail transfers simultaneously one spermatophore (Haase & Baur, 1995). The spermatophore is formed and filled with sperm during copulation (Hofmann, 1923). It has a dis- tinctive form consisting of a head, a body (sperm con- tainer with 800,000—4,000,000 spermatozoa) and a tail 2— 3 cm long (Baur et al., 1998; Locher & Baur, 2000). The snails mate repeatedly in the course of a reproductive season, and fertile sperm can be stored for more than 1 year (Baur, 1988). Mating was found to be random with respect to shell size and different degrees of relatedness (Baur, 1992a; Baur & Baur, 1997). A controlled labora- tory experiment showed that one successful copulation per reproductive season is sufficient to fertilize all the eggs produced by an individual (Chen & Baur, 1993). However, there is a probability of 5-8% that a copulation will not lead to fertilization of eggs (no sperm transfer or transfer of unfertile sperm; Chen & Baur, 1993). In the present study we examined whether A. arbus- torum that remated after 7—8 weeks delivered more sperm than snails remating after 3-4 weeks. We also investi- gated whether sperm delivery is influenced by courtship and mating behavior in this snail species. MATERIALS anp METHODS Maintenance of Test Snails To obtain virgin A. arbustorum, subadult individuals that had not yet completed shell growth were collected in a subalpine forest near Gurnigelbad, 30 km south of Bern, Switzerland (46°45'N, 7°27’E; at an elevation of 1320 m above sea level) on 13 May 1999. The snails were kept isolated in transparent plastic beakers (8 cm deep, 6.5 cm in diameter) lined with moist soil mixed with powdered limestone (approximately 4 cm) at 19° + 1°C and witha light/dark cycle of 16:8 hr for 7 weeks. During this pe- riod, subadult individuals reached sexual maturity as in- dicated by the formation of a flanged lip at the shell ap- erture. Fresh lettuce was provided ad libitum as food. The beakers were cleaned twice per week. Mating Trials Mating trials were performed outdoors to expose snails to natural temperature and light conditions. Two random- Page 225 ly chosen active snails (individuals with an extended soft body and everted tentacles) were allowed to copulate in a transparent plastic container, measuring 14 x 10 x 7 cm, whose bottom was covered with moistened paper towels to maintain activity. One of the two snails was marked on its shell with a spot of correction fluid (Tipp- Ex®) to be able to distinguish between the two partners when recording their behavior. The animals showed no visible reaction to the marking procedure. Mating trials were initiated in the late evening (after 10 p.m.) and ran during 14 nights in June (first copulations) and July and August 1999 (second copulations). The period between the end of May and the middle of July is the time of maximum mating activity in subalpine populations of A. arbustorum. The snails’ mating behavior was observed at intervals of 30 min (at night using a flashlight) following the meth- od described in Baur (1992a) and Baur et al. (1998). Re- cords included time until initiation of courtship, courtship duration (time interval from courtship initiation to copu- lation), and copulation duration. The initiation of court- ship was defined as the first simultaneous oral contact, which was usually accompanied by a slight eversion of the penial lobe in one of the snails. The beginning of copulation was defined as the first simultaneous penis in- tromission. Observation sessions were terminated either when two snails copulated or after 6 hr if no snail initi- ated courtship behavior in a test arena. Snails that did not mate were tested again 3—7 days later with a new partner. In the period between two trials, the snails were kept isolated as described above. In all, 39 copulations were observed in 177 trials (22.0% successful trials). After copulation, one mating partner (hereafter referred to as sperm donor) was kept isolated in a transparent plas- tic beaker lined with moist soil (as described above). The other mating partner (hereafter referred to as sperm re- cipient) was frozen immediately after copulation. To assess the influence of the interval between two copulations on the number of sperm delivered, sperm do- nors were allowed to remate with a randomly assigned virgin partner either 3—4 weeks or 7—8 weeks after the first copulation (Figure 1). One sperm donor of the first group died before the second mating. Seven sperm donors remated after 3—4 weeks (7 copulations in 99 trials; 7.1% successful trials) and 11 sperm donors after 7—8 weeks (11 copulations in 107 trials; 10.3%). In the latter group, two snails did not deliver any spermatophore in the sec- ond copulation. These animals were omitted in the data analyses, reducing the sample size of this group to nine. To assess any size effect of the sperm donor on the number of sperm transferred and number of eggs pro- duced, we measured the size (shell breadth and height) of each mating snail to the nearest 0.1 mm using vernier calipers and calculated the shell volume using the for- mula: Page 226 week 3-4 The Veliger, Vol. 45, No. 3 6 weeks Dy Sa Donors Oia x x egg count week 7-8 6 weeks 2s aa egg count x Receivers ®) V ®) W/ ®) V ~~ x ~~ sperm count (16) (7) 1st copulation 2nd copulation sperm count sperm count (9) 2nd copulation Figure 1. Design of mating experiment with sample size in parentheses. shell volume = 0.312 X [(breadth)? X height] — 0.038 (measurements in mm; B. Baur, unpublished data). Shell volume is a more reliable measurement of snail size than weight because weight depends on the state of hydration and thus is highly variable in terrestrial gastropods. To obtain the spermatophore we dissected out the fe- male reproductive duct of the recipient. The length (L) and width (W) of the sperm-containing part of each sper- matophore were measured to the nearest 0.1 mm using a dissecting microscope. Spermatophore size (in mm*) was approximated, by the formula (mLW7/4), assuming a cy- lindrical volume. Spermatophores were kept singly in Ep- pendorf tubes at —30°C until required. The beakers of sperm donors were checked twice per week for eggs. The eggs of each batch were collected, counted, and kept in a plastic dish (6.5 mm in diameter) lined with moist paper towels at 19° = 1°C to determine hatching success. Newly hatched snails were separated from remaining unhatched eggs to prevent egg cannibal- ism (Baur, 1992b). In both groups of snails, eggs were collected over a period of 40 days following the second copulation. Sperm Counting Procedure The number of sperm that an individual delivered was assessed by counting the number of sperm in the sper- matophore transferred. This procedure is described in de- tail by Locher & Baur (1997). The spermatophore of A. arbustorum consists of a hardened secretion which en- capsulates the spermatozoa (Hofmann, 1923). We me- chanically disrupted the spermatophore in 200 pl PBS- buffer (138.6 mM NaCl, 2.7 mM KCl, 8.1 mM Na,HPO, x 2H,O and 1.5 mM KH,PO,) using a pair of microscis- sors. The sperm suspension was homogenized with a set of Gilson pipettes for 5—15 min. To count the sperm, the homogenate was stained for 1—3 hr with an equal volume of a gallocyanin-chromium complex which stains the DNA in the head of the spermatozoa. If spermatozoa still occurred in clusters, we treated the sample overnight with a sonicator (35 kHz). Two subsamples of known volume of the sperm suspension were diluted 1:3 with PBS-buffer and transferred to a Biirker-Tiirk counting chamber. This counting chamber consists of 16 cells each with a volume of 25 nL. We counted all sperm heads in randomly chosen cells until the total number of sperm heads exceeded 400 and used the average of two subsamples to calculate the total number of sperm in a spermatophore. Data Analyses The StatView program package (Version 5.0, Abacus Concepts, 1998) was used for statistical analyses. Means C. Hanggi et al., 2002 Page 227 Table 1 Mating behavior, sperm delivery, and female fecundity in A. arbustorum that remated either after 3-4 weeks or after 7— 8 weeks. Data from the second copulation are shown (egg number, hatching success of eggs, and number of hatchlings relate to the entire experimental period). Mean values + SE are presented. P-values result from unpaired f-tests. Length of intermating interval Trait Time until initiation of courtship (min)! Courtship duration (min)! Copulation duration (min)! Spermatophore volume (in % of spermatophore size in the first copulation) Sperm (in % of sperm in the first copulation) Total number of eggs produced! Hatching success (%)* Total number of hatchlings! ' Jog ;>-transformed. 2 arcsine-transformed. + 1 SE are given unless otherwise stated. We only con- sidered snails that copulated twice and set the significance level a at 0.01 to compensate for the large number of statistical tests based on data of the same individuals. To improve normality, some variables were /og/0- or arc- sine-transformed. RESULTS First Copulation The size of the spermatophore delivered during the first copulation varied from 1.93 to 3.84 mm? (x + SE = 2.74 + 0.16 mm?, n = 16). The number of sperm transferred in the first copulation ranged from 1,281,800 to 3,599,700 (2,151,000 = 165,600, n 16) and tended to be posi- tively correlated with the size of the spermatophore (r = 0.53, n 16, P = 0.032). Furthermore, spermatophore size tended to be positively correlated with the shell size of the sperm donor in the first copulation (r = 0.51, n = 16, P = 0.044). However, no correlation was found be- tween number of sperm delivered and the shell size of the sperm donor (r = 0.04, n = 16, P = 0.89). Similarly, no correlation was found between spermatophore size, respectively, sperm number and the shell size of the sperm recipient in the first copulation (spermatophore size: r = 0.49, n = 16, P = 0.0513; sperm number: r 0.16, n = 16, P = 0.56). Virgin snails needed 105 min (median, range 30—360 min, n = 16) to initiate courtship. The median courtship _ time was 285 min (range 180-540 min, n = 16) and the median copulation duration was 150 min (range 90—300 min, n = 16). Neither courtship nor copulation duration was significantly correlated with the number of sperm transferred in a spermatophore (Spearman rank correla- 3—4 weeks 7-8 weeks (n = 7) (n = 9) t P 107 + 14 113)3) ae 3S) 0.17 0.86 416 + 45 263 + 28 3.09 0.008 120 + 9 130 + 13 0.49 0.63 87.0 + 10.3 99.4 + 6.3 1.07 0.30 106.1 + 18.1 110.2 + 17.4 0.16 0.88 64.4 + 20.0 50.0 + 10.1 1.23 0.24 64.7 + 11.1 72.1 + 7.4 0.70 0.50 48.4 + 15.4 Seis) ae Oy 1.22 0.24 tion: courtship r, = 0.27, n = 16, P = 0.29; copulation r, = —0.14, n = 16, P = 0.59). Effect of Intermating Interval Snails that remated after 3-4 weeks did not differ in shell size from those that remated after 7-8 weeks (mean shell volume of both groups: 1.24 cm, range: 1.07—1.39 cm?; t = 0.09, df = 14, P = 0.93). There were differences in mating behavior between the two groups of snails. Courtship duration was shorter in individuals that remated after 7-8 weeks than in snails that remated after 3—4 weeks (Table 1). However, time until initiation of court- ship and copulation duration did not differ between snails of both groups (Table 1). Furthermore, mating propensity (percentage of snails that mated in the trials) did not dif- fer between the two groups (7.1% vs. 10.3%; x* = 0.66, df = 1, P > 0.4). Compared with the first copulation, however, the average mating propensity was lower in the second copulation (8.7% vs. 22.0%; x? = 13.29, df = 1, P< 0.001). The difference in intermating interval did not affect spermatophore size and the number of sperm delivered in the second copulation (Table 1). Furthermore, individuals of neither treatment group differed in the number of sperm delivered in the first and second copulation (paired t-test; intermating interval 3—4 weeks, t = 0.17, df = 6, P = 0.87; intermating interval 7-8 weeks, t = 0.25, df = 8, P = 0.81). The number of sperm transferred in the second copulation averaged 2,130,000 (range 1,014,900— 3,537,600, n 16). No correlation was found between number of sperm delivered in the second copulation and the shell size of the donor and that of the receiver (donor: r = 0.20, n = 16, P = 0.46; receiver: r = 0.12, n 16, P = 0.66). Furthermore, snails of both treatment groups Page 228 did not differ in female reproductive success (number of eggs produced and hatching success of eggs; Table 1). Moreover, female reproductive success did not differ be- tween the two groups of snails when only a period of 40 days following the second copulation is considered (t- tests, in all traits P > 0.36, data not shown). DISCUSSION The present study showed that the number of sperm transferred in a copulation of A. arbustorum did not in- crease when the intermating interval was prolonged from 3-4 to 7-8 weeks. This finding supplements the results of a previous study which indicated that individuals of A. arbustorum require at least 8 days to replenish their sperm reserves after a successful copulation, and that there is a slight increase in number of sperm delivered in the second copulation when the intermating interval ex- tends to 22—29 days (Locher & Baur, 1999). In simultaneously hermaphroditic opisthobranchs and pulmonates, the ovotestis produces both spermatozoa and ova, sometimes but not always simultaneously (Duncan, 1975). In Helix pomatia, autosperm are stored in the sem- inal vesicle of the hermaphrodite duct throughout the year (Lind, 1973). Phagocytosis of autosperm by the her- maphrodite duct epithelium has been reported in H. po- matia and Oxychilus cellarius (Miiller, 1774) (Rigby, 1963). Sperm can be expelled from the hermaphrodite duct at times other than copulation to be eventually di- gested (as are foreign sperm) in the bursa copulatrix. In this way, unfertile and old spermatozoa can be recycled. In many animal species, sperm number is an important determinant for achieving successful fertilization in sperm competition (Birkhead & Meller, 1998). In gastro- pods with internal fertilization, sperm are transferred to the partner in the form of free sperm, i.e., as sperm sus- pension in seminal plasma, or the sperm are either ag- gregated into loosely assembled naked conglomerates (spermatozeugmata) or encapsulated into spermatophores (Mann, 1984). However, little information is available about the number of sperm delivered in different gastro- pod species. In the sea hare Aplysia parvula Guilding in Morch, 1863, the number of sperm transferred is posi- tively correlated with copulation duration. When mating duration increased from 2 to 47 min, the number of sperm transferred increased from 1 X 10° to 6 X 10° (Yusa, 1994). In Aplysia kurodai Baba, 1937, and A. juliana Quoy & Gaimard, 1832, the number of fertilized eggs laid by an individual, which was allowed to mate only once, is positively correlated with copulation duration (Yusa, 1996). The ratio of transferred sperm to fertilized eggs is approximately 30:1 (Yusa, 1996). Most freshwater pulmonates transfer a seminal fluid in which sperm is embedded (Geraerts & Joosse, 1984). During one copulation, the freshwater pulmonate Bulinus globosus ejaculates at least 350,000 sperm (Rudolph, The Veliger, Vol. 45, No. 3 1983). Bulinus globosus (Morelet, 1866) is able to cop- ulate as male once per day for up to 8 consecutive days. Following a single copulation, after 1 week of isolation, the hermaphroditic duct of male-acting individuals con- tained an average of 87,000 + 42,000 (SD) sperm. In the 10 days following the initial copulation, the snails pro- duced approximately 50,000 sperm per day. Arianta arbustorum transfers its spermatozoa in sper- matophores. The ratio of transferred sperm to fertilized eggs is approximately 50,000:1, if one copulation is con- sidered, or 25,000:1, if two copulations are considered. These figures significantly exceed the corresponding ratio recorded in Aplysia (see above). The present estimates of sperm number coincide with estimates of two indepen- dent studies using snails from the same subalpine popu- lation: the number of sperm delivered averaged 2,185,100 (n = 91, range 802,620—3,968,800) in Baur et al. (1998) and 2,573,000 (n = 31, range: 907,000—5,825,000) in Locher & Baur (1999). In contrast, lower numbers of sperm were transferred in three A. arbustorum popula- tions in the Austrian Alps (mean values: 1,707,000 (n = 14), 1,615,000 (15), and 1,802,000 (14), respectively; Baminger et al., 2000). However, the latter estimates were obtained from snails copulating in the wild, while higher sperm numbers were observed in animals kept under lab- oratory conditions. It is possible that geographical vari- ation in number of sperm delivered exists in A. arbusto- rum. The production of sperm will certainly vary de- pending on the environment, the age, size, and nutritional state of the snail and most probably on the level of sperm competition. In the present study, snails showed a higher mating propensity when they were allowed to copulate for the first time in June (22.0%) than when they were allowed to remate in July or August (8.7%). We used the per- centage of individuals that mated in the trials as a mea- sure of mating propensity. This is an indirect measure of mating frequency. A previous study showed that the more active a snail is, the more likely it will initiate courtship (Baur & Baur, 1992). Using similar experimental proce- dures, mating propensity ranged from 10.0% to 33.3% in different A. arbustorum populations (Baur & Baur, 1992). In natural populations, mating frequency decreases after the peak period (May to June). A similar seasonal de- crease in mating propensity was observed in the present experiment. Most interestingly, snails prevented from re- mating for 7-8 weeks showed a shorter courtship duration than those prevented for 3—4 weeks. This difference can- not be explained by different conditions in the mating trials between the two experimental groups, as air tem- perature was similar during the test nights (Hanggi, 2000). On the other hand, seasonal effects on courtship duration cannot be ruled out. Courtship duration might also be short if there is no (or little) conflict between the gender roles in hermaphroditic mating partners (see Mi- chiels, 1998). In A. arbustorum, copulations toward the C. Hanggi et al., 2002 end of the reproductive season may mainly serve to re- plenish allosperm reserves in the storage organ as no fur- ther eggs are produced. In this situation, little sexual con- flict may occur between the gender roles. This hypothesis needs testing. However, individuals prevented from re- mating for a longer period did not differ in female fecun- dity (number of eggs produced and hatching success of eggs) from those that remated earlier, confirming that one successful copulation per reproductive season is sufficient to fertilize all the eggs produced by an individual (Chen & Baur, 1993). Acknowledgments. We thank all those who supported our work in any way, in particular D. Hanggi, E. Hanggi, S. Hanggi, O. Joos, M. Krause, and M. Wurtz. A. Baur, A. Erhardt, and two anonymous reviewers provided constructive comments on the manuscript. Financial support was received from the Swiss Na- tional Science Foundation (Grant no. 31-53688). LITERATURE CITED ABACUS CONCEPTS. 1998. StatView (Version 5.0). Abacus Con- cepts Inc.: Berkeley. BAMINGER, H., R. LOCHER & B. BAurR, 2000. Incidence of dart shooting, sperm delivery, and sperm storage in natural pop- ulations of the simultaneously hermaphroditic land snail Ar- ianta arbustorum. 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Factors regulating sperm transfer in an hermaph- roditic sea hare, Aplysia parvula Morch, 1863 (Gastropoda: Opisthobranchia). Journal of Experimental Marine Biology and Ecology 181:213-—221. Yusa, Y. 1996. Utilization and degree of depletion of exogenous sperm in three hermaphroditic sea hares of the genus Aplysia (Gastropoda: Opisthobranchia). Journal of Molluscan Stud- ies 62:113—120. The Veliger 45(3):231—249 (July 2, 2002) THE VELIGER © CMS, Inc., 2002 On the Adaptive Function of the Love Dart of Helix aspersa MICHAEL A. LANDOLFA Max Planck Insitute for Behavioral Physiology, Postfach 1564, 82305 Starnberg, Germany! p) Abstract. The phenomenon of “dart shooting” in land snails of the genus Helix remains unexplained from an adaptive viewpoint. Data on the sexual behavior of Helix aspersa and H. pomatia compiled from previous accounts, supplemented with new observations, do not support the traditional hypotheses that the dart serves reproductive isolation or behavioral stimulation/coordination functions. For example, successful copulation does not depend on dart receipt. An alternative class of explanations for dart shooting is considered: sexual selection. Sexual selection hypotheses for dart function, including certainty of parenthood, male manipulation, and female choice (by both fisherian runaway and indicator mechanisms) are reviewed and compared against the observational evidence. The theory of female choice by handicap/ indicator/good genes processes is implemented to propose that dart shooting is a male sexual signal used by females to select sperm from among sperm donors. Male manipulation and female choice are not easily distinguishable as adaptive explanations of dart shooting. INTRODUCTION The sexual behaviors exhibited by many hermaphroditic land snails (Gastropoda, Pulmonata, Stylommatophora) are well known for their complexity and vigor. A bizarre feature is the sometimes forceful deployment of calcare- ous spines and darts, as well as of non-calcareous organs. The gross anatomy of these organs and, in some cases, the behaviors associated with them, have been described for many species (references below). It is therefore sur- prising that these features have not been better investi- gated from a behavioral ecological perspective. In fact, empirically supported adaptive explanations for their function are lacking. This is not to say that zoologists have been uninterested in snail sexual behavior and reproduction. The occurrence and natural history of spine, “dart,” and “‘stimulator”’ (sarcobelum) use in land snails were noted even before Ashford’s (1883) monograph describing darts and asso- ciated structures in British helicids (references in Koth- bauer, 1988). Subsequent descriptions for stylommato- phoran pulmonates include: for Helix, Cepaea, Theba, Tacheocampylaea, Eobania, and Arianta (family Helici- dae): Meisenheimer (1907, 1912), Szymanski (1913), Taylor (1914), Hofmann (1923), Dorello (1924), Graefe (1962), Herzberg & Herzberg (1962), Petersen (1971), Lund (1971), Lind (1976), Jeppesen (1976), Giusti & Le- pri (1980), Chung (1987), Beaumont (1988), Giusti & Andreini (1988), and Adamo & Chase (1988); for Phen- acolimax (Vitrinidae), Milax (Milacidae), Arion (Arioni- dae), Parmacella (Parmacellidae), and Limax and Dero- ' Current address: Max Planck Institute of Molecular Cell Bi- ology and Genetics, Pfotenhauerstrasse 108, 01037 Dresden, Germany; e-mail: landolfa@mpi-cbg.de ceras (Limacidae): Adams (1898), Gerhardt (1933, 1935, 1940), Quick (1946), Webb (1950), Langlois (1965), Rymzhanov & Schileyko (1991), and Reise (1995); for Ventridens (Zonitidae): Webb (1948); for Helminthoglyp- ta (Helminthoglyptidae): Webb (1951, 1952); for Partula (Partulidae): Lipton & Murray (1979); for Gymnarion (Urocyclidae): Binder (1976); for Euglandina (Streptax- idae): Cook (1985); and for Philomycus (Philomycidae): Webb (1968) and Tompa (1980). Most of these studies were carried out from a perspective of proximate mech- anism rather than ultimate adaptation, if function was considered at all. Nonetheless, several hypotheses have been put forward to provide adaptive explanations for snail precopulatory behaviors, and specifically for dart shooting (Dorello, 1925; Diver, 1940; Goddard, 1962; Lind, 1976; Charnov, 1979; Tompa, 1980, 1984; Chung, 1987; Giusti & Andreini, 1988; Leonard, 1991, 1992: Adamo & Chase, 1990, 1996; Baur, 1998). None has re- ceived unambiguous empirical support. This paper has three main purposes: (1) I first describe the sexual behavior of Helix aspersa (Miiller, 1774) and H. pomatia (Linnaeus, 1758). (2) I then review and com- ment on some of the published hypotheses purporting to explain dart function in these species. Most of these are not wholly consistent with the observed behavior and bi- ology, whereas others may be plausible but remain un- tested. (3) Lastly, I apply the hypothesis of female choice based on male sexual signals (Andersson, 1994; Charnov, 1979; Fisher, 1915) as an adaptive explanation for dart shooting in Helix: dart shooting is a male sexual signal used by females as the basis upon which to select sperm from among several mates. Females choose the fathers of their offspring based on their perception of their mates’ dart shooting effectiveness. However, whereas Charnov (1979) explained female choice based on the dart using the fisherian runaway mechanism, I invoke the concept of indicators for ““good genes”’ (“‘handicaps,’’ Andersson, 1994; Grafen, 1990a, b; Iwasa et al., 1991; Zahavi, 1975, 1977; Zahavi & Zahavi, 1997). The hypothesis is consis- tent with the known behavior and reproductive biology, but is as yet untested. Although stylommatophorans are simultaneous reciprocal hermaphrodites, I distinguish “male” and “‘female” attributes throughout this paper. METHODS Helix aspersa individuals were collected in Dublin, Ire- land and Berkeley, California, USA and purchased from Blades Biological (collected in County Kent, United Kingdom) in March and April 1996. Additional speci- mens were collected in Vienna, Austria in September of the same year. Within 1 week of receipt, all snails re- ceived a unique number painted onto the shell with white non-toxic paint, and were isolated in individual clear plas- tic half-liter cups with tight-fitting lids. Cups contained 2-3 cm of sand and potting soil mixture. Throughout the experimental period (May 1996—September 1997) the an- imal cages were cleaned and the snails showered and fed twice weekly with raw vegetables (lettuce, cucumber, car- rot, cabbage); crushed oyster shells were provided ad li- bitum. A total of 246 sexually mature snails, identified as such by the presence of a reflected shell lip, were subjected to a surgical procedure to check for possession of a dart in the dart sac and for the presence of macroendoparasites of the accessory sexual organs. For surgeries, snails were anesthetized/immobilized with 0.1 ml/g of body weight of 0.01% succinyl choline chloride and 4% MgCl, with 0.005% added streptomycin (Chung, 1985). An approx. 0.75 cm incision was made in the right side of the body wall approx. | cm behind the genital aperture. The dart sac and digitiform glands were lifted out through the in- cision with a polished glass probe and examined under low magnification with a dissecting microscope. In 106 out of the 246 snails (43%), the dart sac and digitiform glands (Figures 5, 7, 8) were excised; the remainder of the surgeries were sham manipulations. In all surgeries, two sutures were inserted to facilitate wound healing. Snails usually regained body turgor and mobility within 18 hours. Survivability | week following the surgery was 83%, there was no significant difference in survivability between dart sac and digitiform-excised and sham-oper- ated snails. Sexual encounters of H. aspersa were staged by intro- ducing 6—12 showered snails into a 10 L plastic basin. Pairs displaying signs of sexual receptivity were removed to a smaller clear plastic cup where they were continu- ously and closely observed until they either broke off sexual behavior or achieved successful copulation. The occurrence and timing of all behaviors, including dart The Veliger, Vol. 45, No. 3 shooting and receipt, were recorded for 156 sexual en- counters. Nineteen H. pomatia sexual encounters were observed and recorded in the field on the grounds of the Max Planck Institute for Behavioral Physiology near Starn- berg, Germany during the spring and summer of 1997. No dissections were performed on H. pomatia. DART-SHOOTING BEHAVIOR IN HELIX The sexual behavior and reproductive biology of Helix aspersa and H. pomatia (Helicidae, Helicinae) have been well documented. The account given here of H. aspersa and H. pomatia matings is similar to those of Meisen- heimer (1907), Jeppesen (1976), and Giusti & Lepri (1980); Lind (1976), Chung (1987), and Adamo & Chase (1988) gave more quantitative descriptions. The first and second parts of this section cover the precopulatory and copulatory behaviors of H. aspersa and H. pomatia, whereas the third part addresses additional matters con- cerning dart shooting and the biology of Helix. Results not attributed to previous works have been derived from my own dissections and observations of sexual encoun- ters. Sexual Behavior Upon meeting, two receptive H. aspersa raise their heads slightly and engage in bouts of mutual facial ca- ressing, mouth-mouth and mouth-genital pore contact, and biting. These behaviors may be punctuated by inter- ruptions (1-20 min in duration) in which the snails sep- arate and/or circle clockwise about one another. The ex- tensive physical contact during this initial phase (“‘intro- ductory behavior,” Lind, 1976) may allow each snail to gather information via mechanical and/or chemical cues regarding the species, size, health, and/or sexual receptiv- ity of its prospective partner. ““Receptivity” is here only loosely defined. A receptive snail attempts to initiate sex with every snail that it contacts; other receptive individ- uals respond to advances from any initiator, whereas non- receptive snails shun such advances. Although subtle pre- copulatory mate choice may exist in Helix and other hel- icids, there is no direct evidence for it (but see Fearnley, 1996). For example, Baur (1992) and Baur & Baur (1997) found that matings in Arianta arbustorum (Helicidae, Ar- iantinae) occur randomly with respect to shell size and degree of relatedness, respectively. Within 1-12 minutes after contact between receptive individuals, the genital pore region (GPR), on the right side of the head, becomes swollen. The genital atrium partly everts, and each snail presses its GPR against that of its partner (Figure 1). The mutual GPR contact alter- nates with mouth-mouth and mouth-GPR contact, biting, and pauses. Helix aspersa pairs maintain a side-to-side posture, and although they may raise their heads slightly, each snail retains substrate contact with nearly the entire M. A. Landolfa, 2002 Page 233 Figures 1-4. Courtship of Helix aspersa. Images are from different courtship sequences. For scale, snail shells are approx. 2.7 cm along their longest dimension. Figure 1. Early in courtship; neither snail has shot its dart. The genital pore regions (GPRs) of both snails are swollen and everted (white tissue masses between snails’ right tentacles), and each snail presses its GPR against that of its partner. Figure 2. The left snail has just ejected its dart (white pointed object emerging from right side of head). The dart did not strike the partner. Figure 3. Unilateral copulation attempt; the snail on the right has everted its penis. The swollen GPR of its partner (to immediate left of penis) is apparent. Figure 4. Successful mutual copulation. Intromission was achieved approx. 2 min before photo was made. The shot dart of the lower snail can be seen protruding from the recipient. foot (Adamo & Chase, 1988; Chung, 1987). In contrast, H. pomatia partners press the front one-third to one-half of the ventral surfaces of their feet together in a “‘sole- to-sole’” posture, raising their heads in a “frontal up- right” position (Meisenheimer, 1907; Lind, 1976). After a variable length of time (in H. aspersa, 5—90 min following initial GPR swelling; personal observa- tion), one partner performs dart shooting by forcibly ejecting its dart from the genital pore (Figure 2). As Helix aspersa partners are usually in GPR-GPR contact at the time of dart shooting, the shot dart often hits the recipient in or near the GPR; a well aimed and forcefully expelled dart may penetrate the partner’s body wall. If the shoot- er’s GPR is not appressed to the partner upon shooting, the dart may miss the intended recipient or strike it with- out penetrating. Most sexual behaviors in H. pomatia proceed more slowly than in H. aspersa, and the postures differ (Jep- pesen, 1976; Lind, 1976). Prior to dart shooting, and start- ing from the sole-to-sole, frontal upright posture, H. po- matia lowers its head, usually pressing its GPR against the sole of its partner. Lind (1976) noted that H. pomatia appears to perform orientation movements before dart shooting. He observed that these movements do not “‘lead the atrium (GPR) to a specific goal for the dart,’ but rather ensure that the shooter’s GPR is appressed against the partner such that the dart strikes the latter upon being shot. The location of striking and/or penetrating darts dif- fers between the two species, reflecting the different pos- tures of the partners at the time of dart shooting: in H. aspersa most darts (60%, Chung, 1987) hit the recipient in or near its GPR, whereas H. pomatia darts usually hit Page 234 The Veliger, Vol. 45, No. 3 the sole of the foot (75%, Lind, 1976). However, as the partners are not always aligned exactly as described above during dart shooting, darts are received in both species in the head, mantle, penis, body side wall, and foot. Some shot darts miss the intended recipient entirely (8—10%, Adamo & Chase, 1988; Koene & Chase, 1998a; 12%, personal observation; all data from H. aspersa). The response to being shot ranges from no observable reac- tion to a brief (< 30 sec in H. aspersa) recoil away from the stimulus, although in rare cases (< 2% of pairings, Chung, 1987) the encounter may be terminated. In H. aspersa, immediately after the first partner shoots its dart, that snail begins attempting intromission (Figure 3): it presses its swollen GPR against that of the partner and periodically (approx. 1/1—5 min) everts its penis. The snail which has not yet shot its dart appears not to allow unilateral intromission; nor does it commence penis ever- sions itself. Instead, a variable period elapses during which the first dart-shooter attempts intromission unilat- erally while the second snail remains in the “‘pre-shoot- ing” stage, in which it presses its GPR against its partner without everting its penis (Chung, 1987; Adamo & Chase, 1988; personal observation). Zero to 120 minutes after the first dart-shooting event, the second snail shoots its dart, after which it too commences penis eversions. The sequence and variability of dart shooting and the ini- tiation of intromission attempts are qualitatively similar in H. pomatia (Lind 1976; personal observation). Copulation and Spermatophore Transfer In H. aspersa pairs, near-simultaneity of bilateral in- tromissions appears to be required for successful copu- lation, as each snail appears not to allow intromission by its partner unless it also achieves intromission. (This is discussed below in the section ‘“Existing Hypotheses for Helix Dart Function, Sexual Selection/Conflict Hypothe- ses.) In order to achieve successful mutual intromission, it appears necessary that the interval within which H. aspersa partners execute simultaneous penis eversions is 5—6 sec or less (personal observation). In addition to near-simultaneity, successful bilateral intromission ap- pears also to require proper orientation of the partners, such that both penes are properly “aimed.” As a result of the apparent difficulty in accomplishing this feat, the time between the onset of mutual intromission attempts and successful mutual copulation is quite variable, in the range 1-120 min for H. aspersa. Partners usually perform multiple penis eversions before achieving mutual copu- lation; Adamo & Chase (1988) reported a mean of 11 per copulant in H. aspersa. Nonetheless, undisturbed pairs that have begun mutual copulation attempts usually suc- ceed (95% of cases in H. aspersa, n = 65 pairs, personal observation). Once successful mutual intromission oc- curs, H. aspersa copulants become quiescent and assume a stereotypical posture with the tentacles extended but flaccid (Figure 4). After approx. 15—30 min, the tentacles are fully withdrawn and the snails maintain almost com- plete quiescence throughout the duration of copulation (Adamo & Chase, 1988: personal observation). Copula- tion in H. pomatia differs, and is described below. Helix aspersa, H. pomatia, and many other helicids do not transfer naked sperm during copulation, but rather package it within a spermatophore (H. pomatia, Lind, 1973). In H. aspersa, formation of the single spermato- phore (per snail) begins in the epiphallus and flagellum within 2 minutes after intromission (Adamo & Chase, 1988). Filling of the spermatophore follows, and the sperm-filled spermatophore enters the penis 2—5 hr after the onset of copulation. Bidirectional spermatophore trans- fer is completed after approx. 5—6 hr, and copulation lasts 6-8 hr (H. aspersa, Adamo & Chase, 1988). Occasionally (8% of pairings, personal observation) partners separate before one or both spermatophores have been completely transferred; O—5 cm of allospermatophore tail can then be seen dangling from the genital pore. The tail is taken up over the next 1—2 hr, but variable lengths of its tip may break off before uptake (10% of 105 spermatophore trans- fers, personal observation for H. aspersa). The apparent mutual enforcement of mutual intromis- sion and its resulting near-simultaneity apply also to H. pomatia, but other aspects of copulation and spermato- phore transfer differ in this species: copulation lasts just 5—10 min, and only the spermatophore head and body are transferred during intromission. Formation and filling of the spermatophore are accomplished in < 5 min (Lind, 1976). Afterward, the penes are withdrawn and the part- ners remain immobile and in sole-to-sole contact while the allospermatophores are actively taken up by both snails. Spermatophore tails can easily be seen being trans- ferred for several hours following withdrawal of the pe- nes. Each partner (H. pomatia) aids spermatophore trans- fer by generating distally directed muscular waves of con- traction of its sole (Lind, 1976; personal observation). Complete uptake requires up to 9 hr (mean 5.5 hr, Lind, 1976), during which the snails remain quiescent. The spermatophore consists of a head/neck, a body holding the sperm, and a long tail (Meisenheimer, 1907; Lind, 1973; Adamo & Chase, 1988). The spermatophore of H. aspersa is 12-15 cm long (Adamo & Chase, 1988), whereas that of H. pomatia is 10-12 cm (Lind, 1973). In H. aspersa the spermatophore is placed into the receiving snail’s bursa diverticulum (Figure 5). Helix pomatia lacks a bursa diverticulum, and in this species the spermatophore is accepted instead into the bursa copulatrix. During sper- matophore transfer, the spermatozoa remain quiescent, but they become activated and begin to exit the spermatophore through its grooved tail approx. 45 min after copulation (H. pomatia, Lind, 1973). Individual sperm are approx. 850 pm long (H. pomatia, Thompson, 1973). Baur et al. (1998) found that the amount of sperm trans- ferred in spermatophores of A. arbustorum was uncorre- M. A. Landolfa, 2002 lated with the sizes of either donor or the partner, the du- ration of copulation, the partner’s previous mating history (virgin or non-virgin), or the amount of sperm received. Control of sperm transfer amount would be expected if males exercise mate choice or if partners “‘trade’’ sperm, i.e., if sperm donation is conditional on sperm receipt. During and after successful spermatophore transfer, the female reproductive tract generates peristalses that pull the allospermatophore into the bursa diverticulum (H. aspersa, Koene & Chase, 1998b) or bursa copulatrix (H. pomatia, Lind, 1973). In H. pomatia the spermatophore exceeds the receiving bursa copulatrix in length, but despite this length advantage it is caused to “‘crumple up” by the receiver’s peristalsis and is pulled entirely into the tract approx. 6— 18 hr after copulation (Lind, 1973). The bursa complex functions not to store transferred allosperm but, by the se- cretion of digestive enzymes, to break down the spermato- phore and destroy the sperm remaining in it. In order to escape digestion and to be stored for possible later fertil- ization of eggs, spermatozoa must move against the peri- stalsis to reach the spermatheca (sperm storage organ) at the opposite end of the spermoviduct. Distally directed peristalsis of the spermoviduct further retards the migration of allosperm (Figure 5; Lind, 1973). As the reproductive tract may actively inhibit allosperm from reaching the sper- matheca, variation in the strength and/or frequency of peri- staltic activity could influence the amounts of transferred sperm which are stored vs. destroyed. Curiously, Chen & Baur (1993) and Locher & Baur (2000) found that 8% and 10%, respectively, of A. arbustorum failed to lay fertile eggs following a single successful copulation, and in my own experiments with H. aspersa, 21% of twice-mated snails (n = 29) failed to lay eggs over a subsequent 2- month period. There are many reasons why snails might not lay fertile eggs after copulating, but one possible rea- son is that none of the sperm received during those cop- ulations was successfully stored. The anatomy of the spermatheca indicates that the sep- arate storage and/or retrieval of sperm from different mat- ings is at least a possibility. The spermatheca is composed of three to six blind-ended tubules, the walls of which are muscular and lined with ciliated epithelium (H. po- matia, Lind, 1973; H. aspersa, Brisson et al., 1977). The spermathecae of the helicine helicids Eobania vermicu- lata, Tacheocampylaea tacheoides, H. aperta, H. luco- rum, and Theba pisana also consist of “‘one or more blind sacs” (Giusti & Andreini, 1988). The spermatheca is best studied in A. arbustorum, in which allosperm are stored in a spermatheca of similar gross structure (two to nine tubules, Haase & Baur, 1995; Baminger & Haase, 1999; Baminger et al., 2000). It is not yet known if sperm from different matings are stored in separate tubules, but it is clear that individuals can use several tubules for sperm storage (Baminger & Haase, 1999). Further, the intricate musculature, innervation, and ciliation of the spermatheca suggest the capacity to control allosperm movements into Page 235 spermatheca 7 Albumin gland allospermatophore (black) bursa ny copulatrix WK ni gonad spermoviduct bursa diverticulum flagellum dart SSG epiphallus sac A SS aS WC = Gi 3 g.a. V : digitiform YF penis glands body wall genital pore rm. Figure 5. The reproductive organs of Helix aspersa, depicted immediately after successful spermatophore receipt. The allos- permatophore (black) has been received from the partner into the bursa diverticulum. The thickened portion of the spermatophore is the body, holding the sperm; its tail extends down into the genital atrium. The dotted line (hollow arrowhead) running in- ternally from the genital atrium up the spermoviduct to the sper- matheca is the path along which allosperm must traverse in order to be successfully stored. Solid lines with filled arrowheads, drawn outside of the organs, depict reproductive tract peristalses directed against the pathway taken by successfully-stored sperm. A snail’s own spermatophore (not shown) is formed and filled in the epiphallus and flagellum and transferred via the everted penis (here shown retracted). g.a., genital atrium; h.d., hermaphroditic duct; rm., penis retractor muscle; v.d., vas deferens. and/or out of individual tubules (Bojat et al., 2001). Stored sperm remain viable for at least 1 year in A. ar- bustorum (Baur, 1988) and Cepaea nemoralis (Helicidae, Helicinae, Murray, 1964). Fertilization occurs at oviposition, which can take place from 1 day to many months after copulation (H. pomatia, Perrot, 1938 cited by Tompa, 1984). Fertiliza- tion occurs in a pouch located at the confluence of the hermaphroditic duct, the spermathecal duct, and the sper- moviduct (Figure 5; better illustrated by Lind, 1973). Al- losperm are released or transported from the spermatheca to the fertilization pouch, but it is unknown if snails can control the amounts of sperm released from the different spermathecal tubules (see previous paragraph and Bojat et al., 2001). Helix aspersa may produce from zero to several clutches following a single mating (Moulin, 1980). The number of matings achieved by wild individ- uals of H. aspersa 1s unknown, but is likely to be on the order of two to six per year (Baur, 1998). Tischler (1973) Page 236 reported that snails of a small population of H. pomatia in northern Germany copulated at least two to four times per season, and Lind (1988) found that individuals in his larger Danish population of the same species mated at least five to six times annually. Murray (1964) and Baur (1994) reported that the offspring of wild individuals of Cepaea nemoralis and A. arbustorum, respectively, were fathered by more than one individual. The behaviors of some other helicid species may be in- terpreted similarly. Giusti & Lepri’s (1980) and Giusti & Andreini’s (1988) behavioral descriptions of Eobania ver- miculata, Tacheocampylaea tacheoides, H. aperta, H. as- persa, H. lucorum, and Theba pisana are less quantitative than those of Lind (1976), Chung (1987), and Adamo & Chase (1988), but are qualitatively consistent with the ac- counts given in those reports and here. The one notable exception is that dart shootings were observed to occur simultaneously in pairs of E. vermiculata, T. tacheoides, and T. pisana; the significance of the differences in si- multaneity of dart shootings among species is unknown. In all species studied by Giusti and colleagues, copulation success appeared not to depend on dart receipt. Dart Characteristics The following aspects of dart shooting are discussed because of their potential relevance to the dart’s adaptive function: (7) the fate of a shot dart, (ii) dart composition and regeneration, (ii/) substances transferred by the dart, (iv) common snail parasites, and (v) variability in dart shooting and receipt. (i) Shot darts do not always strike the partner, and even when they do, they do not always penetrate the body wall. In H. aspersa, Chung (1987), Adamo & Chase (1988), and Koene & Chase (1998a) found that a shot dart pen- etrated the recipient’s skin in 67-92% of cases. In the remaining instances the dart either struck the partner but did not penetrate or completely missed. For penetrating darts, the extent of penetration varies from superficial (< 1 mm) to deep (the entire 9 mm length); occasionally a dart is thrust so hard that its tip emerges from the other side of the recipient’s body (Figure 4). The duration of penetration varies correspondingly. Deeply penetrating darts often remain lodged in the recipient’s skin/body for many minutes to hours, and may even be absorbed (al- lodart absorption by the recipient occurred in 6—46% of penetrations in H. aspersa, Chung, 1987; Adamo & Chase, 1988; Koene & Chase, 1998a). Shallowly pene- trating darts usually become dislodged and fall out within seconds or minutes (own data, unpublished). A dart that misses or falls out may simply lie on one of the snails or fall to the substrate. In H. aspersa, of those darts not striking the intended target snail, many are shot so weakly that they are not fully expelled from the shooter’s dart sac (Chung, 1987; personal observation). In these and other cases in which The Veliger, Vol. 45, No. 3 Figure 6. A shot dart (length 9 mm) that missed the intended recipient. The dart base, with adhering digitiform gland mucus, is at bottom. it fails to lodge in the recipient’s skin, the dart may be retracted by the shooter. ““Used”’ and retracted autodarts are held briefly in the dart sac or genital pore, but are later either expelled onto the ground or transferred to the bursa copulatrix/diverticulum (Chung, 1987; J. Koene, personal communication). In any case, a shot dart is not re-used, possibly because upon shooting it becomes phys- ically decoupled from its connection to the “tubercle” within the dart sac. The tubercle, at the base of the dart sac, is the structure upon which the dart forms (Dillaman, 1981). This decoupling is thought to render a dart sub- sequently unusable (H. aspersa, D. Chung, personal com- munication; H. pomatia, Lind, 1973). (ii) Helix aspersa and H. pomatia possess only one dart at a time. The dart of H. aspersa is approx. 9 mm long (Figures 6, 8) and made of aragonite (CaCO,) and a protein scaffold (Hunt, 1979; Dillaman, 1981). It bears four blades over most of its length; a cone-shaped base fits over the dart sac’s tubercle. After dart shooting, 5—7 days are required for dart regeneration (H. pomatia, Jep- pesen, 1976; H. aspersa, Dillaman, 1981; Tompa, 1982). The amount of calcium in a dart (H. aspersa: 0.37 = 0.13 mg, Koene & Chase, 1998a) is approximately equal to that in a single egg, and the mean clutch size for this species is 50-60 eggs (range 20-130, Herzberg & Herz- berg, 1962; Koene & Chase, 1998a). The relative amounts of calcium in darts and eggs and the fact that the dart is usually not absorbed by the recipient suggest that the dart calcium does not function as a nuptial gift (Koene & Chase, 1998a), a possibility raised by Charnov (1979) and Leonard (1991). Indeed, J. Koene (unpub- M. A. Landolfa, 2002 lished) found that most of the calcium transferred in an absorbed dart is excreted. (iii) Upon being shot, the dart is liberally coated by a white mucus (Figure 6) secreted by the paired digitiform glands; at least some of the mucus of a well penetrating dart enters the recipient’s haemocoel (H. aspersa, Adamo & Chase, 1990). The composition of the mucus is un- known. Koene & Chase (1998b) found that in vitro ap- plication of the mucus induces contractions of the female reproductive tract. These contractions may influence the dart recipient’s disposition of the shooter’s sperm, an in- terpretation supported by results reported by Rogers & Chase (2001). The size and apparent health (based simply on visual inspection) of digitiform glands vary among snails (Ash- ford, 1883; Taylor, 1914; personal observation). In field- collected adult H. aspersa from California, England, and Austria (the last introduced from ex-Yugoslavia, Reis- chiitz, 1978; W. Fischer, personal communication), dis- colored digitiform glands were found in 2% (n = 92), 23% (n = 92), and 6% (n = 62) of snails, respectively (n = 246; this study). Normal glands are white, and dis- coloration ranges from yellow to brown (Figure 7). Dis- colored glands contain darker and more viscous mucus than do white, apparently healthy, glands. The discolored- gland condition was found only in non-virgins (personal observation), as determined by the snail’s possession of a normal or virgin dart (Chung, 1986b), suggesting that the condition is transmitted venereally. Excluding virgins, the percentages of snails with discolored digitiform glands from the Californian, English, and Austrian pop- ulations were 6%, 29%, and 8% respectively (this study). In addition to the digitiform gland discoloration, the glands and/or dart sac bore dark cysts in 2% of the En- glish and 6% of the Austrian snails (this study). (iv) Wild H. aspersa from its native habitat hosts a variety of parasites, some in the reproductive tract. For example, the nematode Nemhelix bakeri inhabits the dart sac (Figure 8) and other reproductive organs; venereal transmission occurs via the transferred spermatophore (Morand, 1988) and possibly via dart shooting. Heavy infestations of N. bakeri cause decreased fecundity (H. aspersa, Morand, 1989). In my H. aspersa samples, nem- atodes were found in 32% of (native) English non-virgins (n = 22), but in none of the (introduced) California and Austrian snails. Other parasites of land snail reproductive, digestive, or respiratory systems include the sporozoan Klossia helicina (Taylor, 1914), the ciliate Myxophyllum steenstrupi (Taylor, 1914), the flagellate Cryptobia helices (Lind, 1973), the trematode Dicrocoelium dendriticum (Taylor, 1914), the nematode Rhabditis maupasi (Brock- elman & Jackson, 1974), and the mite Riccardoella li- macum (Baker, 1970). These parasites affect host fitness (H. aspersa, Morand, 1989; Graham et al., 1995) and are often transmitted between snails during sexual encounters (personal observation for the mites on H. aspersa; Lind, Rage 237 Figures 7 and 8. Diseases of the dart sac and digitiform glands. Figure 7. Digitiform glands, one healthy (white) and one diseased (gray; brown in life) from the same snail. Individual tubules were transected to show the consistency of the mucus. The gray mucus is much more viscous than the white mucus, demonstrated by the different extents of diffusion into the saline droplet (white arrows). Tubule widths are approx. 0.75 mm. Figure 8. Nematode parasites of the dart sac. The dart sac (left) was excised from a live snail and the dart (right) was expelled manually. Approx. 30 nematodes (Nemhelix bakeri) can be seen in the saline drop; the nematode images appear blurred because the worms were swim- ming. The white flask-shaped line is the edge of the saline droplet under transillumination. The dart is approx. 8 mm in length. 1973 found that the presence of Cryptobia in H. pomatia was correlated with previous sexual activity). Variability in the health of the digitiform glands re- sulting from disease, parasites, and/or other factors, e.g., senescence, should contribute to the total variation in the amount and/or potential bioactivity of the digitiform gland mucus transferred by dart shooting. (v) If a sexually active H. aspersa possesses a dart, it generally shoots it during precopulatory behavior. That is, for those individuals possessing a fully formed dart, dart shooting is not a conditional, i.e., optional behavior (Chung, 1987 and personal communication; personal ob- servation); snails do not “decide” whether or not to shoot The Veliger, Vol. 45, No. 3 a dart during a particular encounter. (But see Adamo & Chase [1988], who reported that H. aspersa failed to shoot a dart, even though individuals had one, in 5% of cases. For at least some reported cases of failures to shoot, it is possible that the dart had in fact been weakly shot and then retracted into the dart sac or genital atrium.) There are, however, two known circumstances in which H. aspersa individuals undergo an otherwise normal mat- ing sequence without shooting a dart. In both cases, the reason for a snail’s failure to shoot is that it lacks a dart. The first instance is that in which a snail mates within approx. 7 days after having shot its dart in a previous encounter. Snails mating in this interval have not yet re- generated a dart, and so do not shoot one. H. aspersa individuals are less likely to remate within a 2-day re- fractory period following copulation (Chung, 1987); H. pomatia will remate with either the same or a different individual, without dart shooting, within 3 days of cop- ulating, after which it also experiences an approx. 5-day refractory period (Jeppesen, 1976; Lind, 1976). The sec- ond case of non-shooting occurs in virgin snails: in order to produce its first dart, a snail must apparently undergo precopulatory behavior, including the dart-shooting phase (Chung, 1986b). Virgin snails occasionally exhibit con- spicuous dart-shooting behavior without expelling a dart; the dart sac is everted, but no dart is present (Adamo & Chase, 1988; personal observation). In A. arbustorum the question whether individuals “‘de- cide” to shoot a dart in a given encounter is unresolved. Baminger et al. (2000) dissected snails post-copulation, checking for the presence and locations of shot and un- shot darts. It was found that 60.5% of mating snails held a fully formed dart in the dart sac after copulation, im- plying that dart shooting occurs in fewer than half of matings, per individual. However, Baminger et al. did not check whether darts found in the dart sac after copulation were detached from the tubercle (H. Baminger, personal communication). As discussed above, dart detachment from the tubercle appears in H. aspersa and H. pomatia to signify an “‘attempt’’ to shoot the dart. Except for Baminger et al. (2000), dart shooting has not been studied as well in A. arbustorum as it has in H. aspersa and H. pomatia. The available evidence and observations (e.g., A. arbustorun’s relatively larger digitiform glands secrete copious amounts of mucus, which is actively ingested by both partners prior to copulation; B. Baur, personal com- munication) suggest that dart shooting and mucus pro- duction function differently in A. arbustorum as opposed to H. aspersa and H. pomatia. The above discussions highlight the fact that both dart shooting (occurrence, “force,” and ‘“‘aim’’) and receipt, (occurrence, location, extent, and duration of penetration) are therefore quite variable (Lind, 1976; Chung, 1987; Koene & Chase, 1998a). Moreover, the differences in dart shooting effectiveness and in the quantity and quality of digitiform gland mucus transferred by the dart are likely to influence the degree of the putative effect(s) on the recipient. Signal variability correlating with signaler vi- ability/quality is a requirement for the indicator/good genes mechanism of female choice, discussed below. EXISTING HYPOTHESES FOR HELIX DART FUNCTION Although not demonstrated empirically, dart shooting clearly extracts substantial material, energetic, and other costs (e.g., developmental; see the section below “Female Choice Based on the Love Dart, Relevant Aspects of the Reproductive Biology of Helix’). What possible benefit could the dart bring which might offset these costs? Ex- isting hypotheses for dart function are of three types (Chung, 1987): reproductive isolation, sexual behavior coordination/stimulation, and sexual selection/conflict. Reproductive Isolation Hypotheses Some early workers (Diver, 1940; Webb, 1952) pro- posed that dart systems evolved and/or currently function to prevent interspecific matings. For many years, until the 1970s, the literature abounded with such explanations for species-specific sexual displays. However, there are sev- eral reasons for doubting the validity that this function is the primary one, both for the darts of Helix, in particular, and for sexual signals in general (Zahavi & Zahavi, 1997). First, it is illogical that such a costly feature as dart shooting, performed late in the mating sequence, evolved expressly to prevent interspecific matings. If interspecific copulations result in low-fitness offspring and/or extract other fitness costs, selection would favor unambiguous, early, and relatively cost-free species recognition. In some sympatric Helix species, e.g., H. aspersa and H. lucorum, interspecific mating encounters have never been reported, even though sexually active individuals of both species were kept together for months or years (FE Giusti, personal communication; personal observation). The scarcity of reported helicid interspecific mating attempts suggests that species recognition occurs soon after initial contact between snails. The hypothesis also predicts that, in order that the dart be used for species discrimination, its associated behav- ioral, physiological, and/or morphological parameters should be species-specific. The gross similarity of dart use among species and the wide variation in dart-shooting parameters within species are contrary to the species-dis- crimination hypothesis. Perhaps the species-specificity of dart shooting lies in the morphology of the dart, or in the composition of the dart mucus? Dart morphologies differ among species (Tompa, 1980), but it is doubtful that snails can “‘perceive”’ the shape of received darts, espe- cially given the variability in dart shooting/receipt. Re- garding the possibility that the dart mucus is species-spe- cific, the only relevant result is Chung’s (1986a) finding M. A. Landolfa, 2002 that the helicine helicid Cepaea nemoralis exhibited GPR swelling and eversion when injected with H. aspersa mu- cus. The C. nemoralis response was qualitatively identical to H. aspersa’s response to injection of H. aspersa digi- tiform gland extract. It is therefore unlikely that the dig- itiform gland mucus acts as a species recognition cue. Third, the hypothesis predicts that interspecific mating encounters should proceed readily up to the point of dart shooting, immediately after which the pair should break off their interaction. Reports of interspecific sexual en- counters in helicids are rare, so it is difficult to find evi- dence either supporting or refuting this point. Beaumont (1988) reported that C. nemoralis and C. hortensis en- gaged in interspecific pairings in dense mixed-species ex- periments. The interactions were not observed carefully enough, however, to determine whether dart shooting in- fluenced copulations. Petersen (1971) reported a single case of interspecific sexual behavior in which both part- ners (C. nemoralis and C. hortensis) passed through dart shooting. Only the C. hortensis shot a dart, but this did not strike the C. nemoralis; this latter individual exhibited dart-shooting behavior, but no dart was observed. Both snails attempted intromission but the pair failed to cop- ulate. In this well described interspecific mating attempt, the failure to copulate appeared to result not from receiv- ing the incorrect dart, but rather from incompatible cop- ulation behavior. The two partners did not terminate their interaction at the critical stage of dart shooting. Finally, Webb (1951) observed an instance of courtship between two species of Helminthoglypta (Helminthoglyptidae). The individual of the larger species shot a dart into the smaller partner, which was gravely injured by the dart receipt. The courtship did not proceed, and the smaller, darted individual died 4 days later. The seriousness of the injury caused by the dart in this case renders Webb’s ob- servation difficult to interpret with regard to the dart-as- reproductive-isolation-mechanism hypothesis. Tompa (1980) reported that there are no other recorded obser- vations suggesting that potential interspecific matings are inhibited by the dart. The logic and evidence reviewed above indicate that the dart-as-reproductive-isolation-mechanism hypothesis should not be considered as a viable adaptive explanation of dart shooting. Sexual Behavior Stimulation/Coordination Hypotheses The second hypothesis proposes that dart shooting stimulates the recipient sexually, facilitating temporal co- ordination between the partners and thereby increasing the likelihood that they achieve copulation. For many years, partner stimulation and/or coordination was a pri- mary explanation for the function of precopulatory/court- ship behavior in general (Bastock, 1967). Evidence spe- cific to Helix consists of observations of the immediate Page 239 effects of dart shooting and receipt, or of injection of digitiform gland mucus, on sexually active snails. A common idea has been that the digitiform gland mu- cus transferred by the dart contains a bioactive substance that stimulates the recipient. Dorello (1925) injected dig- itiform gland mucus into H. aspersa and found that the treatment elicited body wall musculature contractions and stimulated the nervous and reproductive systems. God- dard (1962) found in H. aspersa that the injury to snails caused by dissection induced activity of the penis, and proposed that dart penetration would have the same ef- fect. He reported no effect of injection of digitiform gland mucus on the penis, concluding that the penis activity was induced by the physical trauma of dart receipt. Injection of digitiform gland extract by Bérnchen (1967) in H. po- matia increased the frequency and amplitude of heart contractions. Chung’s (1986a) injection of H. aspersa with digitiform gland extract caused eversions of the gen- ital atrium and/or penis, in agreement with Dorello (1925). His conclusion was that “‘the dart may be used for traumatic inoculation of the mating partner with a contact pheromone that enhances sexual receptivity.” Adamo & Chase (1988) compared the durations of sex- ual stages in dart recipients and non-recipients of H. as- persa. The only difference found was the time between the first and second dart-shooting events: if the first dart hit and penetrated the recipient, the time to the second dart-shooting was significantly reduced by a mean of 26 min. No correlations were found between dart shooting/ receipt and either the interval from the second dart shoot- ing to successful copulation or the duration of copulation. The mean duration of the entire mating sequence was approx 490 min; the 26 min reduction thus represents a 5.5% time savings. Adamo & Chase (1990) subsequently showed, using dart sac- and/or digitiform gland-extirpated snails, that the decrease in courtship time was caused by the digitiform gland mucus, not by dart receipt alone: snail pairs that shot “‘dry”’ darts experienced matings that lasted as long as dartless pairings. Injection of digitiform gland extract into sexually active snails similarly pro- duced a small but significant decrease in time-to-copu- lation, but only if the injection occurred when the snail was at an intermediate stage of sexual arousal (Adamo & Chase, 1990). Digitiform gland extract injection also in- hibited locomotion and induced a temporary increase in the level of GPR eversion. Adamo & Chase (1990) con- cluded that the dart mucus contains a pheromone that reduces the time that the partners are in different, non- complementary stages. They speculated, but did not dem- onstrate, that this effect raises the likelihood that pairs copulate successfully. The hypothesis that dart shooting functions to stimulate mutual sexual behavior, thereby increasing the probability of successful copulation, is contradicted in two thorough studies. Lind (1976) tested in H. pomatia whether dart receipt affected the partners’ level of sexual activity, du- Page 240 ration of precopulatory behavior, and probability of suc- cessful copulation. By switching partners between two snail pairs (putting the first dart shooters together) he cre- ated pairs in which neither partner received a dart. Snails manipulated in this way mated normally. He found that such pairings resulted in significantly shorter, not longer, times-to-copulation; precopulatory behavior in pairs in which neither snail, one snail, and both snails received a dart lasted on average 3.0, 4.2, and 5.2 hr, respectively. He further reported that the post-dart-receipt behavior of a snail depended chiefly on that snail’s activity level just prior to being shot: if the recipient was active before be- ing shot, it remained active; if passive, it remained pas- sive. Of those snails showing a change in activity upon dart receipt, twice as many became /ess active than more so. These observations led Lind (1976) to conclude that no facilitative effect of the dart on subsequent behavior of the recipient exists. Lind’s (1976) analysis was largely descriptive, al- though he did not refrain from commenting on the ap- parent non-adaptiveness of dart shooting. In contrast, Chung’s (1987) study of sexual behavior in H. aspersa was undertaken deliberately ‘‘in order to document in de- tail the courtship of this snail and to determine whether dart receipt stimulates courtship or has another function.” Chung (1987) carefully assayed the behavior of paired snails that either received a dart or not. As measures of sexual arousal he used the biting rate, the fraction of time spent out of mutual genital contact, and the rate of at- tempted copulation. He found no significant differences in the first two parameters between dart-receiving and non-dart-receiving snails. Additionally, in snails receiving a dart there were no significant differences before and after dart receipt in the biting rate or the fraction of time spent out of genital contact. Snails receiving a dart had significantly /Jower, not higher, rates of attempted copu- lation (the third parameter, above) than those not receiv- ing a dart. In contrast to Adamo & Chase (1988, 1990), Chung (1987) did not find that the time between the first and second dart-shooting events was shorter if the first dart penetrated the recipient. What can be concluded regarding the hypothesis that the dart functions to stimulate and/or coordinate snail sex- ual behaviors? That dart receipt has no demonstrable ef- fect on the probability of copulation rules out a role for the dart in the overt stimulation of sexual behavior. (How- ever, the effects of dart and/or digitiform gland mucus receipt may not be limited to those observable externally. As mentioned, Koene & Chase [1998b] found that digi- tiform gland mucus induced contractions of the female reproductive tract. The potential adaptive consequences of such “‘cryptic”’ effects of dart receipt are discussed below.) Coordination of sexual behavior by dart shooting may be admitted only if a perverse concept of coordi- nation is applied: at the onset of precopulatory behavior, before the first dart-shooting event, the partners’ behav- The Veliger, Vol. 45, No. 3 iors are well synchronized; they become asynchronous and non-complementary upon the first dart shooting; and they are resynchronized only after the second dart shoot- ing (Lind, 1976). Lind’s (1976) and Chung’s (1987) con- clusions regarding the dart’s effect in H. pomatia and H. aspersa, respectively, were that the dart does not function to synchronize or coordinate sexual behavior. The observations of Giusti & Lepri (1980) and Giusti & Andreini (1988) of matings in H. lucorum, H. aperta, Theba pisana, Tacheocampylaea tacheoides, and Eob- ania vermiculata also fail to support the hypothesis that the dart coordinates/stimulates sexual behavior. These au- thors reported that copulation proceeded normally in the absence of dart receipt, although they did not quantify the times-to-copulation of dart-shooting vs. non-dart-shooting pairs. Giusti & Andreini (1988) hypothesized that dart shooting functions to test the partner’s sexual receptivity or motivation. Assuming that biting and dart receipt rep- resent adverse stimuli, Giusti and collaborators reasoned that only highly motivated snails proceed to copulate in the face of such noxious stimuli. Unmotivated snails would be identified and filtered out by dart shooting, leav- ing sexually motivated snails to concentrate their efforts on like individuals. There is no evidence to support this hypothesis. Once two snails pass through introductory be- havior to the dart-shooting stage, the probability that they will proceed to copulation is quite high (approx. 95% in H. aspersa; personal observation), and does not depend on dart shooting/receipt. Also at odds with Giusti’s hy- pothesis is the fact that, by shooting a dart at a given partner, the shooting snail forgoes the opportunity simi- larly to “‘test’’ other prospective partners for at least 7 days, the time required to manufacture a new dart. Other tactics to assess partner motivation, e.g., the extensive facial, oral, and genital contact occurring prior to dart shooting, would be far less costly to the snail doing the testing. The evidence that dart shooting functions to stimulate the partner’s sexual activity and/or to coordinate the snails’ behaviors is at best equivocal. That dart shooting precedes copulation need not mean that its function is to facilitate the latter act. Sexual Conflict/Selection Hypotheses Explanations of a different sort propose that the dart is an adaptation to resolve sexual conflict. These hypotheses generally assume that one of the sexual roles (male or female) is ‘‘preferred’”’ over the other. That is, the biolog- ical constraints of a hermaphroditic species are such that the cost/benefit ratio of reproduction via one sexual mode is more favorable than that via the other, at least under certain conditions or at specific life history stages. Indi- viduals will be selected to prefer to mate in the role of- fering the better cost/benefit tradeoff. If the same mode is preferred by all or most individuals, a conflict of in- M. A. Landolfa, 2002 terest occurs between potential partners over the assump- tion of sexual roles (Charnov, 1979; Leonard, 1991, 1992). Conflicts of interest may arise between partners regarding the fates of gametes and zygotes and/or the amounts and kinds of resources invested in offspring by each partner. As paternal care is absent in pulmonates, the only conflicts of interest possible in this group are those regarding the extent of maternal provisioning and the fates of gametes. Here I discuss two sexual conflict hypotheses as ap- plied to animal hermaphroditic mating systems: Bate- man’s principle and certainty of parenthood. Bateman’s (1948) principle states that the main factor constraining paternal fecundity is the male’s ability to gain access to females and/or their eggs, whereas the corresponding lim- itation on maternal fecundity is the female’s ability to convert resources into offspring. These constraints give rise to the situation in which potential individual fecun- dity via male function is greater than that via female func- tion. Applied to hermaphrodites, Bateman’s principle im- plies that individual hermaphrodites should prefer to re- produce via the male mode. Extending Bateman’s logic, Charnov (1979) reasoned that simultaneous hermaphro- dites pursue matings not so much to receive allosperm for fertilization (female function), but rather to obtain op- portunities to inseminate partners (male function). Chung (1987) first proposed that the H. aspersa dart serves to resolve the sexual conflict of interest between mating partners. Starting from the assumption that the male role is preferred, he hypothesized that male-acting snails shoot darts to coerce partners into accepting their (the shooter’s) sperm and using it for fertilization. As one possible mode of dart-mediated partner coercion, Chung (1987) speculated that receipt of the dart and/or digiti- form gland mucus might induce oviposition. However, Koene & Chase (1998a) reported no difference in ovi- position rates or amounts between dart recipients and non-recipients (H. aspersa), and Baur & Baur (1992) found that precopulatory behavior, including dart shoot- ing, did not increase oviposition in A. arbustorum. Other possible effects of dart receipt proposed by Chung (1987) are that the dart/mucus may serve to potentiate trans- ferred sperm, inhibit sperm digestion, induce the dis- placement of previously stored sperm, suppress subse- quent mating activity, or inhibit the storage of subse- quently received sperm. He further speculated that “‘the dart may have evolved ... in a kind of evolutionary es- calation that allowed the evolution of increasingly larger or more effective darts to force the partner to act as a female” (Chung, 1987). Chung failed to consider, how- ever, any possible evolutionary response by dart receivers _ to the coercive effects of the dart/mucus: if dart receipt entails a reproductive fitness cost, selection should favor adaptations to counter its effects. Adamo & Chase (1996) restated Chung’s (1987) hy- pothesis more strongly by proposing that dart shooters Page 241 manipulate their partners’ reproductive physiology for their own (the shooter’s) benefit. Adamo & Chase (1996) did not explicitly specify the fitness effect of receiving a shot dart, but by using the term “‘manipulate”’ they imply that the fitness of dart recipients is decreased. The same objection raised above regarding the evolution of resis- tance to the dart effect is applicable here, although Ada- mo & Chase (1996) speculated that the active ingredient in the dart mucus could be identical to a compound used by snails to control their own reproductive functions. If so, then any response evolved to combat the dart mucus effect might also interfere with a snail’s ability to control its own female reproductive processes. More recently, Koene & Chase (1998b) showed that the in vitro application of digitiform gland mucus to H. aspersa preparations induced muscular contractions and reconfigurations of the female genital tract. Specifically, the mucus acted to constrict the entrance to the bursa copulatrix (the sperm digestive organ) and to elicit peri- stalsis in the bursa diverticulum to pull in the received spermatophore. Both of these influences probably affect the fate of received sperm. Koene & Chase (1998b) in- terpreted their result in accordance with Chung’s (1987) and Adamo & Chase’s (1996) explanation for the dart: dart shooting is an adaptation by which males manipulate females to maximize their own (male) reproductive suc- cess. Koene & Chase (1998b) concluded, however, that the reason why males attempt to manipulate females via the dart derives from sperm competition. That is, the evo- lutionary rationale for dart shooting and for analogous male manipulative efforts is that they allow males to com- pete successfully against rival males. Another concept relevant to sexual conflict and pre- ferred sexual roles is “certainty of parenthood” (Leonard, 1991, 1992). In most mating systems, the certainties of parenthood of the female and male are likely to be un- equal; the sex controlling fertilization has greater certain- ty that the investment committed will result in offspring. For example, in promiscuously mating species with in- ternal fertilization, a mated female can ensure that all of the eggs she produces will both be fertilized and be her own, whereas a male is less certain that his mate’s off- spring will be fathered by him. Leonard (1992) proposed that the female role would be preferred in land snails due to that sex’s greater certainty of parenthood. She hypoth- esized that the dart functions as an honest signal that the shooter will perform the less-preferred male sexual role (to donate sperm without guarantee of paternity) in order thereby to have the opportunity to reproduce in the pre- ferred female role (to receive sperm and be guaranteed of maternity). Several predictions pertinent to the mating system of H. aspersa follow from the hypothesis, some of which were addressed by Adamo & Chase (1996). The first prediction of Leonard’s (1992) hypothesis as applied to H. aspersa is that non-dart-shooting individu- als should be unwilling or unable to perform the male Page 242 role, i.e., to donate sperm to their partners. Contrary to this prediction, Adamo & Chase (1988) reported that all snails achieving successful intromission transferred a spermatophore (n = 70), whether they had shot a dart or not. Similarly, Baur et al. (1998) reported all copulants (A. arbustorum, n = 92) transferred spermatophores, 91 of which (99%) contained sperm. Another prediction (Leonard, 1992) is that non-dart- shooting partners are unattractive as female mates be- cause a snail’s non-receipt of a dart might imply that its partner has mated within the last week (and thus recently received allosperm) or is a virgin. The first difficulty with this prediction is that it is not obvious why virgin snails would make poor female mates, as there is no evidence that reproductive abilities are affected by prior experi- ence. Virgin snails may in fact be more attractive mates, as they lack previously stored allosperm and are less like- ly to carry venereally transmitted parasites. Second, non- receipt of a dart need not mean that the partner did not shoot a dart; the partner could have shot but missed. Dart non-receipt is thus not a reliable indicator of a partner’s recent mating history. Further, snails which have recently received sperm may nonetheless be desirable as female mates, as subsequently received sperm can still be stored and used for fertilization. Baur (1994) found in A. arbus- torum that the second (last) male to mate sired a mean of 32% of offspring; the range was 0—100%. Finally, if non-dart-shooting partners make poor female mates, one would expect snails not to copulate unless a dart had been received. This prediction is refuted by Lind (1976), Giusti & Lepri (1980), and Chung (1987). A third prediction (Leonard, 1992) is that snails should refuse to intromit and/or to transfer sperm unless the part- ner reciprocates. That is, snails should decline to copulate as males only. It is true that unilateral intromissions are generally disallowed; the question is whether these are prevented from the male or female side. Rarely, one of a pair of snails succeeds briefly in achieving unilateral in- tromission. In these cases, both Giusti & Lepri (1980) and Chung (1987) reported that the intromitted snail appeared to expel its partner’s unilaterally intromitted penis. Chung (1987) observed in these cases that the intromitting (male-acting) snail assumed the typical copulatory, i.e., quiescent, posture. The female-acting snail, in contrast, attempted actively to pull away and bite the partner’s pe- nis until it was withdrawn. It thus appears that a snail will consent to unilateral intromission only if it is the ‘‘intro- mitter,’’ but will not allow unilateral intromission if it is the “‘intromittee.’’ This is exactly the opposite of what Leonard’s (1992) hypothesis predicts. A theoretical deficiency of Leonard’s hypothesis is that there appears to be no functional or mechanistic reason why dart shooting should serve to signal reliably that a snail will perform the less-preferred male role of deliv- ering sperm. What prevents a snail from shooting a dart and then not transferring sperm? The Veliger, Vol. 45, No. 3 In sum, the hypothesis (Leonard, 1992) that dart shoot- ing in Helix is an adaptation to resolve the sexual conflict between snail partners preferring to. mate as females is logically tenuous, and its empirical predictions appear to be refuted by the available evidence (Adamo & Chase, 1996). FEMALE CHOICE BASED on THE LOVE DART If the critiques given above are deemed acceptable, then only two hypotheses for the adaptive, ultimate function of dart shooting remain viable. (Proximally, dart receipt probably influences allosperm storage and digestion; Ko- ene & Chase, 1998b.) One is that dart shooting is a male manipulative adaptation by which males compete with rival males by influencing their partners’ usage of allo- sperm (Adamo & Chase, 1996). The other is that the dart is a male sexual signal used by females to select sperm received from different mates, i.e., females choose the fathers of their offspring based on their mates’ relative dart shooting abilities (Charnov, 1979). The two hypoth- eses need not be mutually exclusive (Leonard, 1991). In this section I first review the logic of male manipulation and subsequently further develop the female choice hy- pothesis for dart function. I conclude by discussing known aspects of snail biology, as well as further exper- imental work, that may provide clues regarding the rela- tive validity of these two hypotheses. Male Manipulation Chung (1987), Adamo & Chase (1996), and Koene & Chase (1998b) hypothesized that H. aspersa individuals shoot darts in order to manipulate their partners into pref- erentially using their sperm for fertilization. This sort of manipulation is adaptive only if females mate promiscu- ously, and is therefore fundamentally a manifestation of male-male competition over access to females’ eggs. If females were to mate with only a single male, then the reproductive interests of the two partners would be iden- tical—both partners would achieve maximum reproduc- tive fitness via the female’s use of the male’s sperm to fertilize all of her eggs—and the reproductive interests of the male would not be served by his attempting further to alter the female’s use of his sperm. It is only when females receive sperm from more than one male that the interests of male and female partners come into conflict; one consequence of this is that males would then be se- lected to compete vicariously with rival males within the arena of the female (Eberhard, 1996). Selection on males to outcompete rivals for fertilization opportunities leads to the evolution of a class of manipulative strategies for biasing female reproduction, e.g., mate guarding, remov- ing rival sperm, inducing oviposition, and influencing fe- males’ sperm handling (Andersson, 1994). In H. aspersa, the effects of the dart mucus on the female reproductive tract (Koene & Chase, 1998b), leading to the preferential M. A. Landolfa, 2002 storage and/or use of transferred sperm, may represent such an apparently manipulative strategy derived from male-male competition. Although the aim of male manipulative efforts is not explicitly to harm females, but rather to outcompete rival males, the influences listed above are not necessarily in the health and/or fitness interests of females. For exam- ple, copulating male Drosophila transfer to females sem- inal fluid compounds that incapacitate previously stored sperm, thereby providing the last-mating male with a sperm competition advantage (Harshman & Prout, 1994). The effects of these compounds on females are not en- tirely benign; females receiving more seminal fluid prod- ucts suffered an increased death rate (Chapman et al., 1995). Chapman et al. (1998) found that mating reduces survival in females of 10 of 29 insect species from five of nine families. While the data do not represent an over- whelming trend, the positive cases indicate that receiving courtship and/or copulation exacts physiological costs, at least in some species. Further, Chapman et al.’s (1998) own results on the fly Ceratitis capitata point to inde- pendent survival costs derived from copulation (including the receipt of courtship) and from egg production. That is, the simple act of engaging in copulation and in-copula courtship comprises a cost of mating distinct from that of egg production. Additional examples of male strategies to influence female reproduction, and their effects on fe- male physiology and fitness, are given by Eberhard (1996) and specifically in hermaphrodites in Michiels (1998). It is important to distinguish between health/survival costs and total lifetime fitness costs; demonstration of the former does not automatically implicate the latter. In Dro- sophila, in which physiological costs of mating to females have been observed (Fowler & Partridge, 1989; Chapman et al., 1995; Chapman & Partridge, 1996), females allowed to choose their mates produced offspring with greater vi- ability than did females denied a choice of mates (Par- tridge, 1980). Thus, even though females’ receipt of court- ship and mating can damage their health, they can none- theless reap a fitness benefit by using courtship to assess and choose mates. This latter result was confirmed in Dro- sophila by Hoikkala et al. (1998), who additionally showed that specific components of the male sexual signal correlate with viability. Results demonstrating female benefits of choice based on receipt of male courtship have also been reported in other species (Welch et al., 1998; Alatalo et al., 1998). (Studies giving examples in which no significant indirect benefits appear to be derived from mate choice also exist; Alatalo et al., 1998.) The coexistence of these apparently paradoxical consequences of female receipt and assessment of male courtship, i.e., that they exact proxi- mate costs but bring ultimate benefits to females, probably represents a general phenomenon. Can male manipulation alone, arising from male-male competitiion, explain courtship behavior? A potential dis- Page 243 tinction between male manipulation and female choice hypotheses of dart function is that females should reap a net fitness benefit if they are using the information con- tained in the courtship signal as a basis for mate choice, whearas they are unlikely to benefit if they are the objects of manipulation only. Further, if male manipulation has detrimental health effects on females, as in Drosophila (Partridge, 1980) and Ceratitis (Chapman et al., 1998), but females nonetheless gain net fitness from receiving and utilizing sexual signals, then the evolution of cour- ship must be driven at least in part by female choice. Female Choice in Helix: Runaway vs. Indicator Mechanisms Male manipulation does not consider the potential adaptive use by females of information contained in male courtship behaviors. The use of this information to inform mate choice may be selected if it allows choosy individ- uals to bear offspring in higher number and/or of higher quality. In many taxa, including Helix, males provide no direct benefits to their mates; female choice in these spe- cies is therefore unlikely to offer benefits via augmented fecundity. Instead, in species in which males provide nothing but sperm, female choice may bring indirect (ge- netic) benefits only. Charnov (1979) hypothesized that the dart is a male sexual signal coevolved with a female preference for dart shooting via a fisherian runaway process. In runaway, the genes for the male signal trait and for the female pref- erence become linked through assortative mating between males expressing the signal, and females expressing the preference for it (Andersson, 1994). To get started, the process requires that females initially prefer males bear- ing a particular perceivable trait. The specific origin of the pre-existing female preference is irrelevant; for ex- ample, it could be inherent in the species’ sensory system (Ryan, 1990). Although the initial source need not be specified in order to propose subsequent trait-preference coevolution by runaway, Charnov (1979) nevertheless gave two hypotheses to explain why females might ini- tially have preferred ancestral dart shooters: the dart (or its forebear) was a nuptial gift of calcium, and/or it dem- onstrated an increased ability to metabolize that resource. Once a runaway process is underway, it no longer re- lies upon whatever correlation may have formerly existed between the male signal trait and other traits; the genetic linkage between the male signal trait and the female pref- erence is alone sufficient to maintain their subsequent co- evolution. The signal trait is therefore likely to come to be arbitrary with respect to other male characters. Char- nov clearly cited the runaway process itself as. the mech- anism by which dart shooting evolved and is maintained; the hypothesized correlations between the dart and other male qualities were simply his guesses as to how the pro- cess began (Charnov, 1979:2483): “‘One wonders if the Page 244 love darts of some snails are the result of such a (run- away) process.” Twenty years passed before experimental studies were undertaken to test Charnov’s hypothesis regarding dart- based female choice in snails. Koene & Chase (1998a) refuted the idea that the dart is a nuptial gift of calcium: the dart contains too little of that element relative to the amount in a clutch of eggs, and it is only rarely absorbed by the recipient. Further, J. Koene (unpublished) found that the calcium in absorbed allodarts is excreted. The hypothesis given here for the dart’s adaptive function picks up on Charnov’s second notion, that dart shooting is a “demonstration ... of increased ability” (Charnov, 1979:2483). Charnov did not develop this idea into a dis- tinct hypothesis for dart shooting nor as an explanation for the evolution of sexual signals in general. (Subsequent authors have done the latter; Andersson, 1994.) At the time, Zahavi’s (1975, 1977) “handicap principle,’ also known as the “indicator”? and “‘good genes’’ hypothesis when applied to sexual selection, had just been published as an explanation for the evolution of female preferences and male sexual signals. As individual reproductive fit- ness is influenced in part by offspring quality, there is selective pressure on individuals to maximize the genetic quality of their offspring via mate choice. Applied to sex- ual selection, the handicap principle states that honest sig- naling systems evolve in response to selection for the identification of high genetic quality mates: as a result of pressure on individuals to secure mates with good genes, preferences evolve for traits that correlate with, and there- fore indicate, the genetic quality of potential mates. The ideal preferred trait is that whose magnitude varies per- ceivably and reliably with mate quality; these preferred indicator traits can coevolve with the preference to be- come sexual signals. (The handicap principle may be ap- pled to other communication systems, such as between predators and prey. I use “indicator,” as have others [e.g., Andersson, 1994], to refer to a signaling mechanism in which a “handicap” trait conveys information about the genetic quality of potential mates.) Population geneticists were slow to accept the opera- tion of the indicator mechanism (e.g., Bell, 1978), and perhaps Charnov (1979) considered it to be an unlikely explanation for dart shooting. Regardless, the runaway and indicator hypotheses are now thought to be the best explanations for the evolution of preferences for sexual signals (Pomiankowski, 1988; Andersson, 1994; Anders- son & Iwasa, 1996). The hypothesis presented here is that dart shooting in Helix evolved as a male sexual signal used by females as an indicator of mate viability. Females choose the fathers of their offspring by selecting which received allosperm to use for fertilization of their eggs based on their as- sessment of their mates’ sexual signal—dart shooting ef- fectiveness. Charnov (1979) explained the dart by the runaway process; I invoke the indicator mechanism. A The Veliger, Vol. 45, No. 3 crucial consequence of female choice by the indicator mechanism, as opposed to runaway, is that the positive correlation between magnitude of expression of the signal trait and mate quality provided by the indicator mecha- nism allows females to produce offspring of above-av- erage viability. If population viability is sub-maximal and if viability is heritable, females gain a distinct fitness ben- efit via the indicator mechanism. (An additional conse- quence, relevant to species selection, is that sexual selec- tion by female choice by the indicator mechanism poten- tially increases population viability above the level achieved by natural selection alone.) In contrast, in run- away the relationship between the signal trait and mate quality is arbitrary, and so, on its own, sexual selection by the runaway process does not generate increased off- spring fitness, relative to natural selection alone. Gaining indirect fitness benefits via female choice ap- pears simple in principle, but a practical difficulty arises for females: how to identify high-viability mates? Fe- males will generally not be able to evaluate mate viability directly, casually. Instead, they must “‘search”’ for a per- ceivable male trait whose magnitude correlates with via- bility. (““Perception”’ does not require consciousness, nor even nervous system involvement.) Preferences for spe- cific traits may arise as a consequence of sensory biases (Ryan, 1990) or other attributes of a species’s biology. Of the many possible traits expressed by males and pre- ferred by females, the expression of one or some of these traits may be correlated with viability such that high-vi- ability males tend to express the trait better. Other male traits will bear no such correlation, or a weaker one, with viability. Females perceiving and preferring the male trait with the tightest correlation with male viability will con- sequently mate with that non-random sample of males having highest mean viability. If viability is sufficiently heritable and the fitness benefit to females outweighs the cost of choosing (Andersson, 1994), both female prefer- ence and male trait—sexual signal—will be selected. Which male traits correlate best with mate viability, eventually evolving into male sexual signals? The uni- fying feature of such traits, regardless of a given species’s biological constraints, is costliness. Precisely because sig- nals are costly, higher-viability males can better support them than can lower-viability males. Critically, the pro- portional cost that a high-viability male supports by bear- ing a given signal is less than that borne by a low-via- bility male bearing the same-magnitude signal (Grafen, 1990a, b; Getty, 1998). The costliness of sexual signaling therefore ensures the correlation between a male’s viabil- ity and his ability to signal. Such signals are thus non- arbitrary, in that they have evolved so as to be indicators of the bearer’s viability (Zahavi & Zahavi, 1997). Relevant Aspects of the Reproductive Biology of Helix Male manipulation and female choice need not be mu- tually exclusive and can in fact be seen as two sides of M. A. Landolfa, 2002 the same process. According to Eberhard (1998), we can think of females as setting the rules of the game and males as the more active players. Likewise, if female choice occurs in a given species, both the runaway and indicator/good genes mechanisms may be operating. Here I review some aspects of the biology of Helix which may support the female choice perspective of the evolution of the adaptive function of dart shooting. (i) The gross anatomical and behavioral characteristics of Helix and some other helicids provide ample oppor- tunities for mate choice. Courtship and promiscuity allow both the assessment of multiple mates and the receipt of sperm from those mates. The indiscriminate acceptance of sperm from all partners might be taken as evidence against mate choice. However, Helix and some other hel- icids have evolved elaborate anatomical adaptations that allow both the selective digestion and long-term storage of allosperm (Tompa, 1984; Baur, 1998). Of the sperm received from a given single copulation, only a very small portion is stored (Lind, 1973). It is unlikely that the quantities of sperm stored from each copulation are equal, and Koene & Chase’s (1998b) finding that the dart mucus affects contractions of the female reproductive tract suggests that the amount of allosperm stored de- pends on dart receipt, which in turn depends on the part- ner’s dart shooting ability. If an individual’s dart shooting ability correlates with its viability, then female choice in Helix may be manifested by a snail’s ability to control the amount of allosperm stored from each copulation based on its perception of its mate’s dart shooting. This perception need not be “‘conscious,”’ as the regulation of sperm storage by dart/mucus receipt could be mediated by a simple chemosensory/endocrine pathway. Alterna- tively, individuals may exercise female choice by select- ing which stored sperm (of those received from different mates) are used for fertilization of eggs. Such a selective sperm retrieval mechanism would require both the sepa- rate storage of sperm from different mates and a memory of whose sperm is in which spermathecal sac; there is no evidence for either of these phenomena. By whatever mechanism, mate choice by sperm selection in Helix and other species with similar mating systems (Michiels, 1998) may occur cryptically after copulation but be based on information received during courtship before, during, and/or after copulation (Eberhard, 1996, 1998). (i) Can individual snails reap indirect benefits from female choice of mates? The resolution of this issue relies largely on estimates of genetic variation and heritability of viability traits. Potential sources of genetic variation include parasite-host coevolution (Hamilton & Zuk, 1982), immigration of individuals adapted to different lo- cal conditions (Slatkin, 1978), and mutation (Kondrashov, 1988). Although all of these factors likely maintain the genetic variance and heritability of viability traits above zero, the question remains whether the magnitudes of these two parameters in natural populations are sufficient Page 245 to make mate choice worthwhile. Multiple studies (ref- erences in Dupont-Nivet et al., 1997) on genetic variation and heritability in H. aspersa indicate that, for example, shell size is heritable (shell dimension heritabilities of 0.2—0.8 are cited). Dupont-Nivet et al. (1997) found her- itabilities of approx. 0.4 for both shell size and body weight, two traits that likely affect viability. What is lack- ing is a rigorous population genetic analysis determining whether the heritability values found empirically are in fact sufficient to allow mate choice to be adaptive. In addition to the measured heritabilities, a proper analysis would require extensive data regarding the species’s life history, mating system, mutation rates, parasites, etc. In the absence of such a study, it nevertheless seems rea- sonable to propose that snails do indeed have something to gain from mate choice. (ii1) Relevant to the heritability issue is the fact that native populations of Helix and some other helicids har- bor a multitude of parasites. ““Arms races” in which evolving parasite adaptations continuously exert pressure selecting for host counteradaptations are likely to boost genetic variation and heritability of viability traits (Ham- ilton & Zuk, 1982). Of additional interest is the fact that many parasites of helicids inhabit the host’s reproductive tract and/or dart-associated organs themselves; parasite transfer is venereal, and parasitism may directly affect a snail’s ability to generate the sexual signal. (iv) Both the runaway and indicator hypotheses for courtship signal-mediated female choice require that sig- nal magnitude vary among males within the population. This is clearly the case for Helix and some other helicids; although the courtship appears stereotyped, there is sub- stantial variability in dart shooting effectiveness and other parameters. This variability has gone unappreciated, per- haps because of the presumed role for the dart in facili- tating copulation. In fact, the spectrum of dart shooting effectiveness ranges from none at all to sudden, well- aimed, and forceful dart ejection. Additionally, I have ob- served many cases of apparent misfirings, including par- tial and/or premature dart shootings and “‘self shootings” (a single self-inflicted darting was observed in approx. 150 pairings); these misfirings may represent inferior sig- nals by low-viability individuals. Variability in the quan- tity and quality of dart mucus produced would contribute further to total signal variability. (v) Related to this aspect is whether the dart is a “‘cost- ly” signal. In terms of the materials involved the dart cannot be said to be expensive. The amount of calcium in a dart is equivalent to that in a single egg (Koene & Chase, 1998a), which represents less than 1% of a typical season’s production. It is conceivable that the mucus transferred by the dart contains a substance that is costly to produce or acquire, but the composition of the mucus is unknown. However, although there is no evidence that the dart and mucus are materially expensive, dart shoot- ing as a complete behavioral act may be quite costly as Page 246 measured in other currencies. The total cost of dart shoot- ing consists of the efficient “‘presentation” of the signal to the intended receiver. This cost of presentation includes the proximate energetic costs of dart shooting, the geno- mic/information costs of encoding a properly functioning dart system (revealed through congenital defects in dart system function), and the metabolic/anatomical costs of building and maintaining the dart and mucus delivery system. None of these has been estimated in terms either of energy or fitness units, but the wide variation in dart- shooting ability and the not inconsiderable mass and com- plexity of the associated organs are consistent with the notion that dart-shooting is a costly signal (Leonard, 1991). Questions and Further Research Many of the gaps in our knowledge of the biology of Helix are directly relevant to the hypotheses for dart func- tion discussed here. For example, the indicator hypothesis for female choice based on male sexual signals requires a specific relationship between signal magnitude and sig- naler viability (Grafen, 1990a, Getty, 1998): high-viabil- ity males should produce a higher-magnitude signal than low viability males. This question has not been addressed in Helix. The answers to a second set of questions, wheth- er greater dart-shooting effectiveness (signal magnitude) results in greater potential or actual paternal reproductive success, have recently been published. Both the amount of sperm stored by mates (Rogers & Chase, 2001) and paternal reproductive success (Landolfa et al., 2001) have been shown to depend on dart shooting effectiveness. However, the indicator, runaway, and male manipulation hypotheses for dart function all predict that better-shoot- ing snails will experience higher levels of sperm storage and paternal reproductive success. Demonstrations of cor- relations between these parameters will therefore not dis- tinguish among these more ultimate hypotheses for dart function. A third question is that of the bioactive agent in the dart (digitiform gland) mucus. If the mucus is re- sponsible for the differences in allosperm storage and pa- ternal reproductive success, as Koene & Chase’s (1998b) study implies, then a study of its composition would be very useful indeed. Regarding female choice and male manipulation hy- potheses for dart shooting, clarification would be aided by the resolution of whether females benefit from receiv- ing courtship, 1.e., from dart receipt. The putative fitness benefit would derive from female assessment of the male sexual signal, allowing female choice of mates. If females do derive a fitness benefit from dart receipt, can they be regarded as being “‘manipulated”’ by males? On the other hand, the female choice hypotheses would be refuted if it were shown that females suffer a net reproductive fit- ness decrement while males derive benefits from dart shooting. It nonetheless seems possible that both pro- The Veliger, Vol. 45, No. 3 cesses, female choice and male manipulation, have inter- acted to influence the evolution of courtship behaviors and mating systems (Eberhard, 1998). (Manipulation may be more significant in reciprocal hermaphrodites than in gonochorists because the former always participate in courtship simultaneously as both males and females. Se- lection for increasing male mating opportunities neces- sarily ““exposes”’ simultaneous hermaphrodites to higher rates of courtship and mating as a female. In contrast, female gonochorists may better optimize costs and ben- efits of courtship and mating for that sexual mode.) The theoretical feasibility of the operation of female choice raises a further question: whether this mate choice is sustained by fisherian runaway and/or indicator mech- anisms. If signal cost scales with signal magnitude but yet is proportionally lower for high-viability than for low- viability males, it may serve as an indicator of phenotypic viability/genotypic quality. Alternatively, runaway does not specify any consistent relationship between an indi- vidual’s ability to signal and any of its other qualities (besides its ability to attract mates). Because the runaway and indicator processes likely operate synergistically to- ward the same end, rendering their distinction by empir- ical methods has proven to be a challenge. The resolution of these general issues is central to a full understanding of animal courtship, sexual selection, and the evolution of mating systems. Acknowledgments. I thank Thomas Edwards, Wolfgang Fischer, Anne-Marie Groetsch, Julia Lafferty, and Inge Meijer for assis- tance in snail collection and/or care. Lively discussions held in the group of Nico Michiels at the Max Planck Institute for Be- havioral Physiology, Seewiesen, greatly influenced my approach. Communications with Ronald Chase, Joris Koene, and David Rogers of McGill University also contributed to the ideas pre- sented here. 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Oxford University Press: Ox- ford. 286 pp. The Veliger 45(3):250—255 (July 2, 2002) tHE, V ELIGER © CMS, Inc., 2002 Identical Carbonic Anhydrase Contributes to Nacreous or Prismatic Layer Formation in Pinctada fucata (Mollusca: Bivalvia) T. MIYASHITA*, R. TAKAGI, H. MIYAMOTO anpb A. MATSUSHIRO Department of Genetic Engineering, Faculty of Biology-Oriented Science and Technology, Kinki University, Uchitacho, Wakayama 649-6433, Japan Abstract. We have found a carbonic anhydrase (CA) in the prismatic layer of Pinctada fucata. This CA has the same kinetic properties as Nacrein, which is a CA existing in the nacreous layer of Pinctada fucata. We have examined the effects of inhibitors on the enzyme activity. Sodium sulfide and sulfanilamide are typical inhibitors of various types of CA; however, a CA in the prismatic layer and Nacrein were found to be resistant to sodium sulfide and to show a weak resistance to sulfanilamide. This is the first report of a carbonic anhydrase with resistance to sodium sulfide. The molecular mass of the prismatic layer CA was estimated by SDS-PAGE to be approximately 60 kDa. Moreover, we have determined the N-terminal amino acid sequence of a CA in the prismatic layer. The sequence of the first 11 amino acids was in agreement with that of Nacrein, as deduced from the cDNA sequence. From these results, we have concluded that the carbonic anhydrase of the prismatic layer is Nacrein. Nacrein contributes to the formation of a prismatic layer as well as a nacreous layer of mollusk shells as a carbonic anhydrase and is a matrix component. INTRODUCTION Calcite, aragonite, and vaterite are crystal polymorphisms of calcium carbonate in biomineralization (Lowenstam, 1981; Lowenstam & Weiner, 1989). Of these, calcite is the most stable, and vaterite is the most unstable. Ara- gonite is slightly less stable than calcite at ambient tem- perature, but is widespread in marine organisms. Mollusk shells are composed of aragonite and/or calcite, and the organic matrix comprises 0.01-—5% by weight of the shells. In the case of the pearl oyster Pinctada fucata (Gould, 1850), the outer prismatic layer contains calcite, and the inner nacreous layer contains aragonite. These layers contain organic matrix secreted by the mantle ep- ithelia. The organic matrix consists of EDTA-soluble and insoluble proteins (Hare, 1963; Watabe, 1984; Mann, 1988). The formation of the two types of crystal is reg- ulated by the matrix protein constituents. Some of them play an important role in the chemical control of crystal polymorphisms (Belcher et al., 1996; Falini et al., 1996; Samata et al., 1999). It has been suggested that carbonic anhydrases (CA) that catalyze the interconversion of CO, + H,O0 = HCO, + H* participate in the process of calcification (Benesch, 1984; Kakei & Nakahara, 1996) and mollusk shell for- mation (Wilbur & Jodrey, 1955; Freeman, 1960; Meda- kovic & Lucu, 1994). It is believed that the CA of mantle * To whom correspondence should be addressed: Department of Genetic Engineering, Faculty of Biology-Oriented Science and Technology, Kinki University, Uchitacho, Nagagun, Wakayama 649-6433, Japan, Telephone: 0736-77-3888, Fax: 0736-77-4754, e-mail: miyasita@ gene.waka.kindai.ac.jp epithelium facilitates the secretion of HCO, for this cal- cification (Boer & Witteveen, 1980). We have already shown that a 60 kDa protein called Nacrein, which ex- hibits CA activity, exists in the EDTA-extract of the na- creous layer of oyster pearls (Miyamoto et al., 1996). Na- crein 1s an important factor in calcium carbonate crystal- lization, acting as a structural protein and a catalyst that provides the carbonate ion. We predicted that a Nacrein- like protein also participates in formation of the prismatic layer. Based on the results of the present study, we have now identified and characterized a CA in the EDTA-ex- tract of the prismatic layer of Pinctada fucata. Here we report the biochemical properties of prismatic layer CA and discuss the function of CA in biomineralization. MATERIALS AND METHODS Isolation of EDTA-Soluble Proteins The prismatic layer was separated by cutting the shell edges with scissors. After the removal of epiphytes, the shell was crushed to a fine powder. The powdered shell (20 g) was extracted with 100 mL of 0.5 M EDTA (pH 8.0) with continuous stirring for 3 days at room temper- ature. The EDTA-soluble fraction was isolated from the insoluble matrix by centrifugation at 30,000 g for 20 min. The supernatant (80 mL) was dialyzed against 3 li- ters of H,O with three changes. The dialyzed fraction (300 mL) was lyophilized and then dissolved in 10 mL of 10 mM Tris-HCI (pH 8.0). The sample was dialyzed against 10 mM Tris-HCl (pH 8.0), followed by concen- trated. Preparation of the EDTA-soluble extract of the nacreous layer of Pinctada fucata is the same as de- T. Miyashita et al., 2002 scribed above. The amount of protein was determined by using Protein Assay Dye Reagent (Bio-Rad). Carbonic Anhydrase (CA) Assay The assay of carbonic anhydrase activity was per- formed as described by Miyamoto et al. (1996). Six drops of phenol red, 3 mL of 20 mM Veronal buffer (pH 8.3), and 20—200 pL of the test-material-containing solution were mixed and placed in ice water. The reaction was started by the addition of 2 mL of ice-cold water saturated with CO,, and then the time for the pH to drop to 7.3 was measured. Definition of units is as follows: unit = (Ty) — T)/T, where T and Ty are the reaction times required for the pH change from 8.3 to 7.3 at O°C with and without a catalyst, respectively. Assay of enzyme activity in the presence of inhibitor was carried out as follows: all re- agents in the assay mixture except the substrate were pre- mixed in the reaction vessel for 10 min at 0°C. The re- action was started by the addition of the substrate. SDS-Polyacrylamide Gel Electrophoresis (SDS- PAGE) Proteins were subjected to sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis on 10% acryl- amide gels, as described by Laemmli (1970). N-Terminal Amino Acid Determination Proteins of the EDTA-soluble fraction were separated by 10% SDS-PAGE and were blotted onto a PVDF mem- brane (Millipore) using a dry blotting system (Nippon Eido). After Ponceau S staining, the band was cut out and then subjected to N-terminal amino acids sequence anal- ysis. DEAE-Sephacel Column Chromatography Approximately 20 mg of the soluble fraction of the prismatic layer was loaded onto a DEAE-Sephacel (Phar- macia) ion-exchange column (10 X 1.5 cm) equilibrated with 10 mM Tris-HCl (pH 8.0). After washing the column with 5 mL of 10 mM Tris-HCI (pH 8.0), the soluble frac- tion was chromatographed in the same buffer at a flow rate of 8 mL/h using a liner O—0.8 M NaCl gradient. Frac- tions of 2 mL were collected, and carbonic anhydrase activity was assayed. The fractions containing carbonic anhydrase (Fraction Number 31—40) were pooled and then dialyzed for 10 mM Tris-HCl (pH 8.0), followed by concentration to | mL. Gel Filtration Chromatography The concentrated sample was chromatographed over a Cellulofine GCL-300 sf (Seikagaku Kogo Co.) column (95 X 1.5 cm) equilibrated with 10 mM Tris-HCl (pH 8.0) containing 0.2 M NaCl at a flow rate of 12 mL/hr. Page 251 30 —> =i 4—> =e Figure 1. Comparison of SDS-PAGE Pattern of EDTA-soluble proteins extracted from the nacreous and prismatic layers of Pinctada fucata. 10 wg of proteins were subjected to 10% SDS- PAGE. Lane N, EDTA-soluble proteins were extracted from the pearl nacreous layer. Lane P, EDTA-soluble proteins were ex- tracted from the prismatic layer. Lane M, Protein markers (GIB- CO BRL). Fractions of 1.2 mL were collected, and carbonic anhy- drase activity was assayed. Each fraction containing car- bonic anhydrase was dialyzed separately for 10 mM Tris- HCI (8.0) followed by concentration to approximately 100 L. To examine the purity, 20 wL of the concentrated fractions was subjected to 10% SDS-PAGE. RESULTS The protein components of the EDTA-soluble fraction in the prismatic layer were compared with those of the na- creous layer. Proteins were loaded onto 10% SDS-PAGE. The molecular mass of the major protein was approxi- mately 60 kDa in both layers (Figure 1). The 60 kDa protein of the nacreous layer is Nacrein (Miyamoto et al., 1996). We assayed the carbonic anhydrase (CA) activity in the soluble fraction extracted from the prismatic layer. Bo- vine erythrocyte CA and Nacrein in the soluble fraction of the nacreous layer showed notable CA activity (Table 1). The soluble fraction extracted from the prismatic layer also contained CA activity. Although the specific activity was relatively lower than that of bovine erythrocyte CA, it was almost the same as that of Nacrein. The velocity of the enzyme reaction was increased 2 times by using a twofold amount of enzyme. A large amount of Bovine Serum Albumin (BSA), which has no enzyme activity, and a heat-inactivated soluble fraction showed no CA ac- tivity. These results indicate the presence of carbonic an- hydrase in the soluble fraction extracted from the pris- matic layer of Pinctada fucata. We next examined the effects of inhibitors on the CA activity. Sodium sulfide and sulfanilamide are typical in- Page 252 The Veliger, Vol. 45, No. 3 Table 1 Assay of carbonic anhydrase activity of the EDTA-soluble fraction extracted from the prismatic layer of Pinctada fucata. Amount used 4 Specific activity Sample for assay (mg) (sec) (units/mg) a — 410 (= T)) — BSA! 6 430 — BECA? 0.3 50 2.4 X 104 Soluble fraction (nacreous layer) (Nacrein) 3} 40 3.3 X 103 Soluble fraction (prismatic layer) 1.5 100 2.1 X 103 Soluble fraction (prismatic layer) 3 50 Ai SS NOP Soluble fraction (prismatic layer) (heat-inactivated) 3 400 — ' BSA: Bovine serum albumin. > BECA: Bovine erythrocyte carbonic anhydrase. hibitors of various types of carbonic anhydrases (Val, 1996). The activity of bovine erythrocyte CA was almost inhibited by these inhibitors (Table 2), as reported pre- viously (Kiese & Hasting, 1940; Davenport, 1945). How- ever, Nacrein was resistant to sodium sulfide and showed weak resistance to sulfanilamide. These results were iden- tical to those for the prismatic layer CA. To purify the carbonic anhydrase in the prismatic layer, we performed column chromatography. After DEAE-Se- phacel column chromatography, the concentrated sample was passed through a Cellulofine GCL-300 sf column (Figure 2). Each fraction containing an enzyme activity was dialyzed separately for 10 mM Tris-HCl (8.0) and then concentrated to approximately 100 pL. To examine the purity, the concentrated fractions were applied to 10% SDS-PAGE. Fraction number 35 showed a single protein band that was almost homogeneous (Figure 3). The pro- tein had an approximate molecular mass of 60 kDa. Frac- tion number 39 contained a larger amount of the 60 kDa protein than that of fraction 35 as well as a large amount of contamination which had an approximate molecular mass of 40 kDa. However, the total enzyme activity of this fraction was approximately 1.7 times greater than that of fraction 35. From these results, we conclude that the approximate molecular mass of the prismatic layer CA is 60 kDa. We have determined the N-terminal amino acid se- quence of the 60 KDA protein. The sequence of the first 11 amino acids agreed with that of Nacrein as deduced from the cDNA sequence (Figure 4). DISCUSSION Carbonic anhydrase (CA) is a ubiquitous enzyme existing in every tissue and cell type. Various isozymes of CA are now known (Tashian, 1989; Henry, 1996) and play an important role in acid-base balance, ion transport, main- tenance of ionic concentration, and modulation of he- moglobin O, affinity (Cameron, 1979; Henry, 1984; For- ster et al., 1986). CA also participates in biomineraliza- tion, and it is well known that CA is an essential enzyme of calcification (Wilbur & Jodrey, 1955; Freeman, 1960; Table 2 Comparison of the effects of inhibitors on the activity of carbonic anhydrases. CA activity was expressed as a percentage of the activity in the absence of inhibitor. Used amount for assay (mg) Sample Relative activity inhibitor BECA* in Nacreous layer soluble fraction (Nacrein) nin n Prismatic layer soluble fraction in 1 it 1 1 il 1 1 1 1 in * BECA: Bovine erythrocyte carbonic anhydrase. _ Sodium sulfide Sulfanilamide 100 11 2) 100 100 48 100 100 40 T. Miyashita et al., 2002 Page 253 Enzyme activity Cunit/ml) (-----) Fraction Number Figure 2. Cellulofine GCL-300 sf chromatographic profile of CA-containing fractions obtained from a DEAE-Sephacel column chro- matography. Solid line, absorbance at 280 nm; dashed line, enzyme activity. Bore & Witteveen, 1980). The mantle of the mollusk shell contains CA activity (Medakovic & Lucu, 1994; Freeman & Wilbur, 1948). We have recently identified the carbonic anhydrase named Nacrein in the EDTA-soluble matrix of the nacreous layer in oyster pearls and have isolated its cDNA (Miyamoto et al., 1996). Based on the amino acid sequence, Nacrein appears to contain two functional do- mains, one a carbonic anhydrase domain and the other a Gly-Xaa-Asn (Xaa = Asp, Asn, or Glu) repeat domain. It has been assumed that Nacrein contributes to the for- mation of HCO, ions in calcification, and functions as a matrix component of aragonite crystal. The prismatic lay- er contains calcite, which is another polymorphism of CaCO,, in addition to aragonite of the nacreous layer. We Figure 3. SDS-PAGE electrophoretic pattern of CA-containing therefore assumed that the prismatic layer contains a car- bonic anhydrase that differs from Nacrein, and that this enzyme contributes to calcite formation. We have identified in the present study a carbonic an- hydrase in the extract of the prismatic layer of Pinctada fucta. The specific activity was found to be relatively lower than that of bovine erythrocyte CA and almost the same as that of Nacrein. Sodium sulfide and sulfanilamide are well known in- hibitors of CAIT (Davis, 1959, 1961). The carbonic an- hydrase in the prismatic layer was found to be resistant to sodium sulfides and to have weak resistance to sulfa- nilamide. These results are almost the same as those for Nacrein. This is the first report, however, of a carbonic anhydrase resistant to sodium sulfide. The mechanism of resistance to sodium sulfide is unknown. To determine the molecular mass of carbonic anhy- drase in the prismatic layer we further purified the protein A Lo SB 4 & Of Sa NO Al a ((S)) Jul Jt Ise Jel JB) det YC al ID) B LG 8 4b. G7 SG 8) MO aul I Sy WE TF Ise lel Oy dal SC Wal 3D) fractions. Lane M, Perfect Protein® Markers (Novagen). Lanes 1 and 2 correspond to the fraction numbers of 35 and 39, re- spectively. Figure 4. Sequence alignment of the N-teminal of the prismatic layer CA with Nacreion. A. Prismatic layer CA. B. Nacrein. The amino acid in parentheses is uncertain. Page 254 The Veliger, Vol. 45, No. 3 by means of Cellulofine GCL-300 sf gel filtration column chromatography. Subsequently, each fraction containing enzyme activity was subjected to SDS-PAGE. This anal- ysis showed the presence of an approximately 60 kDa protein exhibiting enzyme activity. This molecular mass was equal to that of Nacrein. To determine the amino terminal sequence, PVDF membrane transferred a 60 kDa protein was subjected to a sequence analyzer. The sequence of the first 11 amino acids agreed with that of Nacrein. Based on the results described above, we have concluded that the carbonic anhydrase of the prismatic layer is Nacrein. This result is unexpected, Recently, the cDNA of a Nacreion-like protein called N66 was cloned from Pinctada maxima. RT-PCR analysis of the N66 mRNA revealed that this gene is transcribed in the dorsal region of the mantle, which is responsible for nacreous layer formation, and in the mantle edge, which is responsible for prismatic layer formation (Kono et al., 2000). These results are in agreement with the con- clusions of the present report. The presence of Nacrein in both the aragonite nacreous and calcite prismatic layers is suggestive with regard to the role of the Gly-Xaa-Asn repeat. We assume that this repeat is not related to the regulation of a crystal poly- morphism of calcium carbonate. Recently, a nacreous lay- er-specific new matrix protein family was isolated from the EDTA-insoluble matrix of the nacreous layer of Pinc- tada fucata, and it was shown that this protein family designated N16 (N16-1,2,3) induces an aragonite crystal- line layer (Samata et al., 1999). Based on its amino acid sequence, which is in agreement with N16-3 except that residue 58 is N, Pearlin also belongs to this family (Mi- yashita et al., 2000). It seems likely that Nacrein is involved in the regula- tion of crystal growth and/or morphology via an inter- action between the Gly-Xaa-Asn repeat and certain crys- tal faces or via coordination with another matrix pro- tein(s). Soluble protein(s) that regulate calcite crystal growth or shape by means of an interaction with a calcite crystal surface are already known in shells (Walters et al., 1997) and sponge (Aizenberg et al., 1995). Biochemical characterization of these proteins, however, has not yet been carried out. LITERATURE CITED AIZENBERG, J., J. HANSON, M. ILAN, L. LEISEROWITZ, T. F KOet- ZLE, L. ADDADI & S. WEINER. 1995. Morphogenesis of cal- citic sponge spicules: a role for specialized proteins inter- acting with growing crystals. The Federation of American Societies for Experimental Biology Journal 9:262—268. 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Carbonic anhydrase: a multigene-multifunc- tional enzyme. Anais da Academia Brasileira de Ciencias 69:565-S73. Raves» Watters, D. A., L. SmitH, A. M. BELCHER, G. T. PALOCZI, G. D. Stucky, D. E. Morse & P. K. HANSMA. 1997. Modifi- cation of calcite crystal growth by abalone shell proteins: an atomic force microscope study. Biophysical Journal 72: 1425-1433. WATABE, N. 1984. Shell. Pp. 448—485 in J. Bereiterhahan, A. G. Matoltsy & K. S. Richards (eds), Biology of the Integument. Volume 1. Invertebrates. Springer-Velag: Berlin. WILBUR, K. M & L. JopRey. 1955. Studies of shell formation. V. The inhibition of shell formation by carbonic anhydrase inhibitors. Biological Bulletin 108:82—112. THE VELIGER © CMS, Inc., 2002 The Veliger 45(3):256-258 (July 2, 2002) Thin Layer Chromatographic Analysis of Lutein and B-carotene in Biomphalaria glabrata Maintained on a High Fat Diet YONGHYUN KIM!', BERNARD FRIED?*? AanpD JOSEPH SHERMA! Department of Chemistry! and Department of Biology’, Lafayette College, Easton, Pennsylvania 18042, USA Abstract. Thin layer chromatographic analysis was used to determine lutein and B-carotene in Biomphalaria glabrata snails maintained on a high fat diet of hen’s egg yolk. The mean values of lutein in snails on a Romaine lettuce diet were approximately 3 and 2.5 at 14 and 20 days postculture, compared to those of snails maintained on the yolk diet. Likewise, the mean values of B-carotene for snails on the lettuce diet were approximately X1.5 and X6.6 at 14 and 20 days, respectively, compared to those from the snails on the yolk diet. The only significant differences in values (Student’s t-test, P < 0.05) was at day 20 at which time the mean percent of B-carotene in the snails on the high fat diet was significantly reduced compared to snails on the lettuce diet. The concentration of lutein in the lettuce was about 3.5 that in the egg yolk. The concentration of B-carotene in the lettuce was <8 that in the egg yolk. In general, the concentration of these lipophilic pigments in B. glabrata reflected the content of lutein and B-carotene in the lettuce and egg yolk diets. INTRODUCTION Numerous studies have reported the use of a hen’s egg yolk diet to observe nutrition in uninfected Biomphalaria glabrata (Say, 1816) and snails infected with larval schis- tosomes and echinostomes (see reviews in Fried & Sher- ma, 1990, 1993). These studies have observed mainly the effects of the egg yolk diet on the lipid content of the snails (Fried & Sherma, 1990, 1993), although a recent study by Kim et al. (2001) has examined the effects of this diet on the carbohydrate content of the snail. Because effects of the diet on lipophilic pigments, 1.e., lutein and B-carotene, are not available, this study examined these pigments in snails maintained on hen’s egg yolk. MATERIALS AND METHODS Twenty juvenile Biomphalaria glabrata snails, about 7 mm in shell diameter, were obtained from Dr. Fred Lewis, Schistosomiasis Laboratory, Biomedical Research Insti- tute (Rockville, Maryland, USA). Groups of 10 snails were maintained at 23—24°C in aerated glass containers each containing 800 mL of artificial spring water (ASW) prepared as described by Ulmer (1970). One culture of 10 snails was fed ad libitum on boiled Romaine leaf let- tuce (L diet). The other culture was fed the hen’s egg yolk diet ad libitum, supplemented with 500 mg of Ro- maine lettuce once a week (Y-L diet), as described in Beers et al. (1995). Food and water were changed twice weekly in all cultures. * Author to whom correspondence should be addressed: Tele- phone: 610-330-5463, Fax: 610-330-5705, e-mail: friedb@ lafayette.edu For TLC analysis, the whole-body of five individual snails (n = 5) was prepared for both Y-L and L diets at 14 and 20 days after the cultures were started. To do this, the shell of each snail was gently crushed with a hammer, and the snail body was removed with forceps. Each whole-body was homogenized in 2 mL of acetone in a glass homogenizer. The pellet was washed twice with ac- etone (100 wL), and the washings were combined with the supernatant. The combined supernatant was evapo- rated to dryness under nitrogen and then reconstituted with 200 pL or 300 pL of heptane, as necessary for the scan areas of at least one sample zone to be bracketed within the scan areas of the standard zones in the TLC analysis. Single samples (n = 1) of the hen’s egg yolk (200 mg) and the Romaine lettuce (200 mg) were extract- ed in acetone and prepared for TLC analysis as described for the snail bodies. The standards used for TLC analysis were lutein and B-carotene (Sigma, St. Louis, Missouri). The solid stan- dards were weighed on an analytical balance and diluted with dichloromethane to prepare standard solutions of 0.0100 wg pL! for both lutein and B-carotene. TLC anal- yses were performed on Merck (EM Science, Gibbstown, New Jersey) 10 cm X 20 cm chemically bonded C-18 silica gel plates with concentrating zone (RP-18F,54;, Art. 15498). Plates were prewashed by development to the top with dichloromethane-methanol (1:1) and dried in air in a fumehood. The standards (4.00, 8.00, 12.0, and 16.0 wL for each standard) and 1.00—8.00 ,L of the reconstituted samples were applied in separate lanes in the concentrat- ing zone by means of a 10-~L Drummond (Broomall, Pennsylvania) digital microdispenser in a dark room with minimum lighting. The applied solutions were dried in Y. Kim et al., 2002 Page 257 Table 1 Percent weight of lutein and B-carotene in the snails maintained on the yolk-lettuce (Y-L) diet or lettuce (L) diet. Days after the Pigment cultures were started Lutein 14 0.0213 20 0.00833 R-carotene 14 0.0410 20 0.00840 Y-L* L* + 0.0037+ 0.0624 + 0.015 + 0.0039°+ 0.0198 + 0.0045» + + 0.015+ 0.0600 + 0.026 + 0.0030* ** 0.0530 + 0.00644 * Snail bodies: mean (weight %) + standard error; n = 5 individual snails for each sample (except where indicated). ** Concentration significantly reduced (Student’s t-test, P < 0.05) compared with snails on the L diet. ‘Two data points were below the limit of quantification. Weight % values of 0.00340 and 0.00575 were used for statistical analysis. > One data point was below the limit of quantification. Weight % value of 0.00832 was used for statistical analysis. © Three data points were below the limit of quantification. Weight % values of 0.00288, 0.00311, and 0.00510 were used for statistical analysis. tn = 3. tn = 4. air for about 30 sec. The plates were developed to a dis- tance of about 7 cm past the concentrating zone-bonded silica gel interface with petroleum ether-acetonitrile- methanol (10 + 20 + 20 v/v) in a rectangular Camag (Wilmington, North Carolina) TLC twin-trough chamber. The chamber was covered with aluminum foil, lined with a saturation pad (Analtech, Newark, Delaware), and equilibrated with the mobile phase for at least 15 min before inserting the plate. Approximately 40 mL of mo- bile phase was required for each development. The re- quired development time was about 20 min. The plates were briefly dried in air for about 2 min after develop- ment. The pigments were detected in visible light as col- ored bands on a white background. Quantitative densitometric analysis was performed with a Camag TLC Scanner I with the tungsten lght source (set at 448 nm for lutein and 455 nm for B-caro- tene), slit width 4, slit length 4, and scanning rate 4 mm s_!. The CATS-3 software was used to generate a linear regression calibration curve relating the weights of the standard zones (0.0400—0.160 jg) to their peak areas. The analyte weight in the sample aliquot with a scan area closest to that of the average of the middle two standard zones was determined by automatic interpolation from the calibration curve, on the basis of its peak area. The weight percents of pigments in the snail whole-body were calculated using the equation described earlier (Sherma et al., 1992). For quantification of some samples, dilution or con- centration were required to obtain scan areas that would be bracketed within the calibration curve. An appropriate correction factor was then included in the calculation. On six occasions after the maximum possible degree of con- centration, the largest spotted sample yielded a zone whose area was less than the scan area of the lowest standard zone. Therefore, the exact quantities of the pig- ment in these zones could not be determined because they were below the experimental quantification limit, which ranged from 0.00575—0.0166 weight percent of the pig- ments for the conditions under which the analyses were performed. The reconstitution volume was 200 wL for all six samples, with 4.00, 8.00, 4.00, 8.00, 8.00, and 8.00 wL aliquot spotted, respectively. For these zones, a con- centration of one-half of the limit of quantification was included in the data for statistical calculations (Cline et al., 1999) (see Table 1). RESULTS Anpb DISCUSSION By comparison with the migration of standards, lutein and B-carotene were identified in chromatograms of the whole snail body extracts from snails fed both the Y-L and L diets at R, values of 0.45 and 0.070, respectively. The sample also contained several other pigment zones with different R; values, one of which was qualitatively deter- mined to be chlorophyll A. Table 1 lists quantitative data for lutein and B-carotene in the snails fed both the Y-L and L diet for 14 and 20 days (n = 5 for each sample). The mean values of lutein in the snails on the L diet were 3 and X2.5 at 14 and 20 days, respectively, compared to snails on the Y-L diet. Likewise, the mean values of B-carotene in snails on the L diet were X1.5 and X6.6 at 14 and 20 days, respec- tively, compared to the snails on the Y-L diet. However, the only results that were significantly different (Student’s t-test, P < 0.05) were those for B-carotene values in the snail tissues 20 days after the cultures were started. By this time, snails on the Y-L diet had significantly reduced amounts of B-carotene than snails on the L diet. The weight percents of lutein (n = 1) from the hen’s egg yolk and Romaine leaf lettuce were 0.0730 and 0.253, respec- tively. The weight percents of B-carotene (n = 1) from the yolk and lettuce were 0.0140 and 0.0830, respective- ly. The concentration of lutein in the lettuce was approx- Page 258 The Veliger, Vol. 45, No. 3 imately 3.5 that in the egg yolk. The concentration of B-carotene in the lettuce was approximately 8 that in the egg yolk. The amount of lutein and B-carotene pigments in gen- eral reflected the relative amounts of these pigments in the diets. Thus, concentrations of both lutein and B-car- otene were higher in the lettuce than the yolk diet, and these higher values were reflected in snails on the L ver- sus Y-L diet. These results are in general accord with a previous study by Eidam et al. (2001) that compared var- ious analytes in the tissue and hemolymph of Biomphal- aria glabrata fed a diet of Romaine lettuce leaf versus the midrib of the Romaine lettuce. The leafy portion of the Romaine lettuce contained significantly greater amounts of neutral lipids, phospholipids, lipophilic pig- ments, and carbohydrates than did the midrib portion of the Romaine lettuce. Higher values in these analytes were seen in the tissues and hemolymph of the B. glabrata snails fed the leafy portion of the Romaine lettuce. The adage “‘you are what you eat’ is applicable to the B. glabrata snails. Acknowledgments. We are grateful to Dr. Fred A. Lewis, Head, Schistosomiasis Laboratory, Biomedical Research Insti- tute, Rockville, Maryland, USA, for supplying the Biomphalaria glabrata snails used in this work through NIH-NIAID contract NO1-AI-55270. LITERATURE CITED BEERS, K., B. FrieD, T. FusINO & J. SHERMA. 1995. Effects of diet on the lipid composition of the digestive gland-gonad complex of Biomphalaria glabrata (Gastropoda) infected with larval Echinostoma caproni (Trematoda). Comparative Biochemistry and Physiology 110B:729—737. Cuine, D. J., B. FRIED & J. SHERMA. 1999. High performance thin layer chromatography determination of carbohydrates in the hemolymph and digestive gland of Lymnaea elodes (Gastropoda: Lymnaeidae). The Veliger 42:185-188. Erpam, P. M., J. J. SCHARITER, B. FRIED & J. SHERMA. 2001. HPTLC Analysis of tissue and blood of Biomphalaria gla- brata snails in order to assess the effects of a diet of Ro- maine lettuce leaf versus midrib on the concentrations of lipids, pigments, and carbohydrates. Journal of Liquid Chro- matography & Related Technologies 24:1467—1478. FrieD, B. & J. SHERMA. 1990. Thin layer chromatography of lipids found in snails. Journal of Planar Chromatography— Modern TLC 3:290—299. FrieD, B. & J. SHERMA. 1993. Effects of a high fat diet on the lipid composition of Biomphalaria glabrata (Planorbidae: Gastropoda). Trends in Comparative Biochemistry and Physiology 1:941—958. Kim, Y., B. FRIED & J. SHERMA. 2001. Thin-layer chromatograph- ic analysis of carbohydrates in Biomphalaria glabrata snails maintained on a high-fat diet. Journal of Planar Chromatog- raphy—Modern TLC 14:61-63. SHERMA, J., C. O7HEA & B. FRIED. 1992. Separation, identifica- tion, and quantification of chloroplast pigments by HPTLC with scanning densitometry. Journal of Planar Chromatog- raphy—Modern TLC 5:343—349. Umer, M. J. 1970. Notes on rearing snails in the laboratory. Pp. 143-144 in A. J. MacInnis & M. Voge (eds.), Experiments and Techniques in Parasitology. W. H. Freeman: San Fran- cisco. The Veliger 45(3):259-271 (July 2, 2002) THE VELIGER © CMS, Inc., 2002 NOTES, INFORMATION & NEWS Kalidos griffithshauchleri, sp. nov., Madagascar’s Largest Helicarionid Snail (Pulmonata) Kenneth C. Emberton Florida Museum of Natural History, Box 117800, Gainesville, Florida 32611-7800, USA Introduction Owen Griffiths of Mauritius (along with his associates and assistants) was a major participant in the author’s 1992— 1996 survey and inventory of Madagascar’s land mollusks. Griffiths’ unique and strongest contribution was in survey- ing the Reserve Naturelle Integrale de Tsingy de Bemar- aha, a little-explored limestone karst region in west-central Madagascar. After some preliminary scouting in 1992 and 1993, Griffiths led expeditions in 1995 and 1996 into the southern and central-plus-northern parts of Bemaraha, re- spectively (Griffiths, 1995, 1996). Among the many new species of land snails resulting from Griffiths’ Bemaraha collections (in Emberton, 1999a, b, 2001, 2002, in press) is the remarkable new Kalidos described herein. The genus Kalidos Gude, 1911, is endemic to Mada- gascar; its sister group has been predicted from biogeo- graphic considerations to lie among the ariophantines of India (Emberton & Rakotomalala, 1996). The Faune de Madagascar (Fischer-Piette et al., 1994) listed 71 Kalidos species (23 new), Emberton (1994) added one new species, and Emberton & Pearce (2000) added four new species. Thus this current new species brings the total to 77. The author’s 1992-1996 survey and inventory of Mad- agascar yielded over 2000 lots of Kalidos species. Only 438 of these lots have been identified so far, and the 1995— 1996 Bemaraha Kalidos materials have not been reached yet in this process. However, three specimens of K. grif- fithshauchleri, sp. nov. that were collected in 1992-1993 were sent to the author’s attention some time ago and merit description now—in advance of the author’s plan to mono- graph the genus—because of this species’ unique size and its conservation implications for Bemaraha Reserve. The author’s identifications of 438 of the some 2000 lots of Kalidos have yielded 65 presumed species, of which 42 seem new and undescribed (Emberton, unpublished). Thus Madagascar’s total Kalidos species now in collections is likely to be at least 250 (contradicting Emberton & Rak- otomalala’s 1996: table II estimate of ““75?’’). Most of those species are small, and none begins to approach this new species in its gigantic shell size. All other known and collected Madagascan helicarionids, with the exception of this gigantic Bemaraha species, are much smaller in size (Fischer-Piette et al., 1994; Emberton 1994; Emberton & Pearce, 2000; Emberton, unpublished). Systematics Higher classification follows Ponder & Lindberg (1997), Nordsieck (1986), and Vaught (1989). Type materials are placed in the Florida Museum of Natural History, Uni- versity of Florida, Gainesville (UF) and the Australian Museum, Sydney (AMS). Description follows the format applied to other Kalidos by Emberton & Pearce (2000). Class GASTROPODA Clade HETEROBRANCHIA Clade PULMONATA Order STYLOMMATOPHORA Suborder SIGMURETHRA Infraorder HELICIDA Superfamily HELICARIONOIDEA Family HELICARIONIDAE Subfamily ARIOPHANTINAE Genus Kalidos Gude, 1911 Kalidos griffithshauchleri Emberton, sp. nov. (Figure 1) Kalidos sp. 1, Griffiths, 1995; Griffiths, 1996. Diagnosis: Unique within the genus for its large initial whorls and very rapid whorl-expansion rate producing a gigantic adult shell. Kalidos griffithshauchleri, sp. nov. is most similar to K. bathensis (Robson, 1914), from which it differs in both its larger initial whorls (diameters of first and first-plus-second whorls = 2.2 mm and 5.1 mm versus 1.7 mm and 3.8 mm) and its looser coiling (whorls//n[diameter] 1.51—1.60 versus 1.76). Holotype: UF285447 (1 adult), Owen Griffiths lot A1680: Madagascar: near Tsingy de Bemaraha: 15 km east of Antsalova: in cave mouth, April 1992. Paratypes: UF285448 (1 adult), type lot. AMS C. 204776 (1 adult), Owen Griffiths lot A1737: Madagascar: near Tsingy de Bemaraha: southeast of Antsalova: near Tsiandro: in cave mouth, April 1993. Description of holotype: Shell Size and Shape. Shell rather thick and robust for The Veliger, Vol. 45, No. 3 Figure. 1. the genus. Diameter 58.5 mm, height 38.4 mm (h/d 0.66). Whorls 6.5 (coiling tightness = whorls//n(diameter) = 1.6). Spire angle 155 degrees. Shell domed. Whorl pe- riphery rounded. A faint, rather narrow, subsutural, spiral gutter is present throughout ontogeny. Suture depth one- half whorl from aperture is 1.4% of shell diameter. Sub- sutural line (where inside of shell wall meets previous whorl) not visible through shell. Umbilicus 3% of shell diameter, half covered by columellar reflection of aper- tural lip. Shell color whitish above, and a light yellowish brown below that grades to whitish on the base, marked both by a very conspicuous supraperipheral spiral band that is white, sharply bordered above and below by dark brown to purple-brown, and by a narrower and less con- spicuous subsutural spiral band that is white bordered be- low by dark brown to purple-brown. Aperture. Aperture width (measured parallel to a line between the columellar and upper peristome insertions) 45% of shell diameter. Aperture height-width ratio (height measured to and perpendicular to a line between the col- umellar and upper peristome insertions) 0.90. Distance Kalidos griffithshauchleri Emberton, sp. nov., holotype. Scale bar = 10 mm. between the columellar and upper peristome insertions 87% of aperture width. Penultimate whorl projects into body whorl, occupying 23% of aperture height. Lower peristome angle where it meets parietal wall (apertural view) 20 degrees. Apex. First whorl diameter 2.2 mm. First two whorls diameter 5.1 mm. Embryonic whorls 2.1. Embryonic sculpture (partially eroded) of close-set, dense, wrinkled axial striae crossed by dense, fine spiral grooves. Post-Embryonic Shell Sculpture. Close-set, obliquely axial striae, somewhat uneven in width, crossed by close- set spiral grooves to produce a pustulose appearance. Spi- ral grooves and their resulting pustules fading below the shell periphery, absent from the base, where only axial striae are visible. Variation: Diameter Ht/Diam Whorls Wh//nDiam Holotype 58.5 0.66 6.5 1.60 “Paratopotype” 56.3 0.60 6.1 1.51 Paratype 57.0 0.62 6.2 1.53 Notes, Information & News Page 261 Griffiths (1996) reported a maximum diameter of 65 mm in the central and northern parts of Bemaraha Re- serve. The “‘paratopotype”’ is the freshest shell, with embry- onic sculpture much more sharply detailed than in the holotype or other paratype. Distribution: Bemaraha Reserve and its karstic vicinity, from the Manombolo River north to at least opposite the town of Antsalova, latitudes 18°02’-19°08'S, longitudes 44°32'—44°53’E (Griffiths, 1995, 1996). Ecology: Griffiths (1995, 1996) reported, “This is the most obvious tsingy [=limestone karst] snail at Bemara- ha. It can be found dead all over the tsingy in large num- bers. Aestivates deep inside narrow tsingy slots where it sticks itself firmly to the substrate.” Etymology: For this species’ co-discoverers, Owen Grif- fiths and Jorg Hauchler, both of Mauritius. Acknowledgments. The staff at Ranomafana National Park Pro- ject in Antananarivo helped in getting collecting and export per- mits. Owen Griffiths’ field surveys of Bemaraha were aided es- pecially by Jorg Hauchler, Vincent Florens, and Roger Randa- lana. Literature Cited EMBERTON, K. C. 1994. Thirty new species of Madagascan land snails. Proceedings of the Academy of Natural Sciences of Philadelphia 145:147-189. EMBERTON, K. C. 1999a. New acavid snails from Madagascar. American Malacological Bulletin 15:83—96. EMBERTON, K. C. 1999b. Edentulina of Madagascar (Pulmonata: Streptaxidae). American Malacological Bulletin 15:97—108. EMBERTON, K. C. 2001. Dentate Gulella of Madagascar (Pul- monata: Streptaxidae). American Malacological Bulletin 16: 71-129. EMBERTON, K. C. 2002. The genus Boucardicus, a Madagascan endemic (Caenogastropoda: Cyclophoridae). Archiv ftir Molluskenkunde 130:1—199. EMBERTON, K. C. In press. Parvedentulina and edentate Gulella of Madagascar (Pulmonata: Streptaxidae). Archiv fiir Mol- luskenkunde. EMBERTON, K. C. & M. EF RAKOTOMALALA. 1996. Madagascar’s biogeographically most informative land-snail taxa. Pp. 563-574 in W. R. LourRENCO (ed.), Biogeography of Mada- gascar. Editions de 1 ORSTOM: Paris. EMBERTON, K. C. & T. A. PEARCE. 2000. Helicarionid snails of Mounts Mahermana, Ilapiry, and Vasiha, southeastern Mad- agascar. The Veliger 43:218—247. FISCHER-PIETTE, E., C. P. BLANC, EF BLANC & FE SALvart. 1994. Gastéropodes terrestres pulmonés. Faune de Madagascar 83: 1-552. GRIFFITHS, O. 1995. A preliminary survey of the non marine Mollusca of the southern part of the Reserve Naturelle In- tegrale de Bemaraha in the central west of Madagascar. The Papustyla, 9. GRIFFITHS, O. 1996. A survey of the non marine Mollusca of the central and northern parts of the Reserve Naturelle Integrale de Bemaraha in the central west of Madagascar. The Papus- tyla. NorpsigEck, H. 1986. The system of the Stylommatophora (Gas- tropoda), with special regard to the systematic position of the Clausiliidae, II. Importance of the shell and distribution. Archiv fiir Molluskenkunde 117:93-116. PONDER, W. FE & D. R. LINDBERG. 1997. Towards a phylogeny of gastropod molluscs: an analysis using morphological characters. Zoological Journal of the Linnean Society 119: 83-265. Rosson, G. C. 1914. On a collection of land and freshwater Gastropoda from Madagascar, with descriptions of new gen- era and new species. Zoological Journal of the Linnean So- ciety 32:375-—389, pl. 35, figs. 1-6. VAUGHT, K. C. 1989. A Classification of the Living Mollusca. American Malacologists Incorporated: Melbourne, Florida. 189 pp. Fungi and Other Items Consumed by the Blue-Gray Taildropper Slug (Prophysaon coeruleum) and the Papillose Taildropper Slug (Prophysaon dubium) Rex McGraw!, Nancy Duncan! and Efren Cazares? ‘Bureau of Land Management, 777 NW Garden Valley Boulevard, Roseburg, Oregon 97470, USA "Department of Forest Science, Oregon State University, Corvallis, Oregon 97331, USA Introduction Six species of slugs, in addition to 29 other aquatic and terrestrial mollusk species, were listed in the Record of Decision for the Northwest Forest Plan (USDA and USDI, 1994). They were included in a list of rare taxa associated with late successional forests, referred to as Survey and Manage species, that require additional mit- igation in order to assure their persistence. These species were listed, in part, due to the lack of information on their natural history and ecology. Two Survey and Manage slug species were the focus of this study: the blue-gray taildropper (Prophysaon coe- ruleum Cockerell, 1890) and the papillose taildropper (P. dubium Cockerell, 1890). Studies have shown slugs of other species to be mycophagists (Buller, 1922; Chatfield, 1976; Pallant, 1969). Field observations of these two Pro- physaon slug species on and within partially eaten fungi suggested that they are also mycophagous. We tested this hypothesis by examining fecal pellets from these slug species for evidence of ingested fungal material. Materials and Methods P. coeruleum and P. dubium were collected during field surveys within several proposed timber sale areas in Douglas County, Oregon on Bureau of Land Management lands from March 1998 through May 1999. These were Page 262 The Veliger, Vol. 45, No. 3 Table 1 Frequency of food item occurrence in fecal samples of Prophysaon coeruleum and Prophysaon dubium. (Total # of samples and % of samples containing item). Prophysaon coeruleum Prophysaon dubium Spring Fall Spring and fall Spring Fall Spring and fall Single food item (n = 34) (n = 52) (n = 86) (n = 20) (n = 37) (a = 537) Plant tissue 25) 74% 26 50% 51 59% 14 74% 26 59% 40 63% Lichens 0) 0) 13 25% 13 15% 2 10% 8 18% 10 16% Imperfect fungi 4 12% 6 12% 10 12% 5 26% 4 9% 9 14% Fungal hyphae* 25 74% 42 81% 67 718% 11 58% 32 73% 43 68% Fungal spores* 8 24% 32 62% 40 47% 1 5% 37 84% 38 60% Unidentified 0 0 2 4% DD 2% 2 10% 1 8% 3 5% * Data does not include imperfect fungi. predominantly Douglas fir timber stands ranging in age from 50 years to over 200 years old with average tree diameters at breast height (DBH) of 50 cm to over 100 cm. The majority of fecal samples were collected from slugs located in stands over 80 years of age. Surveys were done during the spring and fall when the forest litter layer was moist and the ambient air temperature was between 4°C and 11°C. The established protocol for Survey and Manage terrestrial mollusks (Furnish et al., 1997) was followed. Time-constrained surveys were conducted in suitable habitat with emphasis on suspected areas of high- quality habitat. Two 81 m? plots in every 4 hectares of project area, specifically located in high-quality habitat, were intensively searched for 20 minutes each. Another 20 minutes was spent at other sites throughout the re- mainder of the 4 ha conducting brief, 1-5 minute oppor- tunistic searches. Specimens of either P. coeruleum and P. dubium were placed individually in clean, white film canisters until they produced fecal pellets (typically within 1—4 hours). Fecal pellets from individual animals were taken as they were produced from the animal or were collected where they fell on the surfaces of the canisters. No substrate or plant material from the discovery site was placed in the canister with the animal. Fecal pellets were removed from the canisters and immediately placed in a vial of 70% isopropyl alcohol. The animals were returned to the site of collection or kept as vouchers. Identification of slug species was done by examination of external physical characteristics only. Only specimens which conformed to the described species were used in this study. Voucher specimens currently reside at the Roseburg, Oregon Field Office of the Bureau of Land Management. For fecal analysis, pellets were moved to small vials of 50% ethanol to dissolve lipid layers of viruses which might pose health threats to humans (Colgan et al., 1997). One to two drops of distilled water were then added to rehydrate the samples for 48 hours at room temperature. Pellets were macerated and mixed thoroughly. The re- sulting suspension was transferred to a microscope slide. One to two drops of Melzer’s reagent (iodine, potassium iodide, and chloral hydrate in aqueous solution) were added and the suspension then covered with a 22 X 22 mm cover slip. One slide was made per sample. Seventy- five fields, each 450 ym in diameter, across three hori- zontal lines of view were then examined on each slide at 250 magnification with a compound microscope. Fun- gal spores were identified to family, genus, or species according to Castellano et al. (1989). Plant material, li- chens, molds, fungal hyphae, and other fungal structures, as well as occasional arthropod fragments and nematodes, were recorded. Quantitative analysis of the frequency of detections of ingested material was not the intended focus of this study, and the methods used were not quantitatively rigorous. For instance, fecal pellets were not equal in volume, re- sulting in unequal dilutions in slide preparations. How- ever, an apparent difference was observed in the propor- tions of fungal and plant material detected in spring sam- ples as compared to fall samples. We investigated this trend using Chi-square tests to detect significant differ- ences (a = 0.05) in the frequency of the types of materials identified between fall and spring seasons, and between slug species within seasons. No significance tests were done on the fungal taxa due to the small sample sizes within several fungal taxa. Results and Discussion Both Prophysaon species in this study showed evidence of consumption of fungi (spores or hyphae of mushrooms or truffles), vascular plant material (both root tissue and other plant tissue), lichens, and imperfect fungi, i.e., molds in their fecal samples (Table 1). Fungi were the most common items found in both P. coeruleum 90% (77/ 86) and P. dubium 82% (47/57) samples, with spores from 10 separate fungal families identified. In addition, fragments of arthropods were found in 8% (11/143) of the samples, and nematodes were found in 6% (8/143) of the samples. Nematodes were seen to be whole and in Notes, Information & News Page 263 Table 2 Summary of fungal spore frequency in fecal samples of Prophysaon coeruleum and Prophysaon dubium. Prophysaon coeruleum Spring Fungal spore identity (n = 35) Subclass: Ascomycotina* 1 3% order: Tuberales 1 3% family: Tuberaceae 1 3% genus: Genea 0) 0 Hydnotrya 0) 0) Pachyphloeus 0) 0) Tuber 1 3% Subclass: Basidiomycotina 6 17% order: Ramariales 0) 0) family: Ramariaceae 0) 0) genus: Gautieria 0) 0) order: Agaricales 6 17% family: Bolbitiaceae 2} 6% family: Boletaceae 2 6% genus: Melanogaster D 6% family: Rhizopogonaceae 2} 6% genus: Rhizopogon 2 6% family: Coprinaceae 0) 0) family: Cortinariaceae 0) 0) genus: Hymenogaster 0) 0) family: Entolomataceae 1 3% family: Russulaceae 1 3% genus: Gymnomyces 1 3% Subclass: Zygomycotina 1 3% order: Glomales 1 3% family: Glomaceae 1 3% genus: Glomus 1 3% genus: Sclerocystis 0) 0) NO ‘Sy Noronuunn FPreNNNPHTOWNKFEDADAWNAWND HH Prophysaon dubium Fall Spring Fall (n = 59) (n = 19) (n = 63) 8% 1 5% 4 6% 8% | 5% 4 6% 8% 1 5% 4 6% 7% 0) 0) 3 5% 0) 1 5% 0) 0) 2% 0) 0) 0) 0) 0) 0) 0) 1 2% 46% 0) 0) 30 48% 2% 0) 0) 1 2% 2% 0) 0) 1 2% 2% 0) 0) 1 2% 44% 0) 0) 29 46% 8% 0) 0 Wf 11% 8% 0) 0) 7 11% 5% 0) 0) 5 8% 10% 0) 0) 3 5% 10% 0) 0) 3 5% 2% 0 0) 1 2% 8% 0) 0) 5) 8% 0) 0 0) 1 2% 0) 0) 0) 0) 0) 7% 0) 0) 6 10% 7% 0 0) 6 10% 3% 0) 0) (0) 0) 3% 0 0) 0) (0) 3% 0) 0) 0 0 2% 0) 0) 0 0) 2% 0) 0) (0) 0) * Numbers given for a subclass, order, or family include both specimens identified to genus as well as those identified only to their respective family or order. good condition, suggesting that they were internal para- sites rather than food items. There was no evidence in- dicating that P. coeruleum and P. dubium had different diets at this level of resolution. While acknowledging that the methods used were not quantitatively rigorous, the data suggest a shift in the diet of both species between spring and fall (Table 1). Both species appear to ingest plant material more frequently in spring than in fall. Fungal hyphae, spores, and lichens were more frequently consumed in fall than spring. Chi- square analysis indicates that P. coeruleum had signifi- cantly more plant material in its fecal samples in the spring than in the fall (x? = 4.716, df = 1, P = 0.030), but had more lichens (x? = 10.014, df = 1, P = 0.002) and fungal spores (x? = 11.938, df = 1, P = 0.001) in the fall than in the spring. P. dubium samples had signif- icantly more spores in the fall than in the spring (x? = 22.185, df = 1, P < 0.001). Spores from taxa in the order Agaricales were most commonly recorded. Most of the fungal spores identified (Table 2) were from mycorrhizal taxa that are root sym- bionts with vascular plants (including many conifer spe- cies) and whose hyphae are attached to the rootlets of such plants. In addition, most of the samples with fungal spores identified were of hypogeous fungal species (49/ 78). The term hypogeous, as used here, includes those species with fruiting bodies occurring within the forest duff layer as well as in mineral soil, such as truffles. All of the other epigeous spore species identified are in the order Agaricales. Twenty-five of the 29 samples contain- ing epigeous fungal spores were collected in the fall, which may help to account for the increased proportion of fungal material in fall samples. Fungal and vascular plant material appear both sepa- rately and together in individual fecal samples. We iden- tified plant tissue composed of root cells and also green plant tissue containing chloroplasts and amyloid granules. Green plant matter was present in the absence of fungal material in 10% (14/143) of the samples, but root tissue was never observed in samples that did not contain fungal hyphae. Fungal material was observed in the absence of plant matter in 37% (53/143). Both plant tissue and fun- Page 264 gal tissue were found together in 52% (75/143) of the samples. These slug species are commonly observed in the for- est floor litter layer or associated with coarse woody de- bris into which conifer roots commonly penetrate. We hypothesize that due to the intimate connections of my- corrhizal hyphae with plant rootlets, root material may have been ingested during the process of foraging for these fungal hyphae. Green plant matter may have been ingested either due to its intrinsic food value or due to the presence of bacteria or yeasts on the surfaces of de- composing material. The presence of spores in 55% (78/ 143) of the fecal samples suggests that fungal fruiting bodies were being deliberately targeted because these structures are not typically closely associated with plant roots. Fecal pellets collected from four other mollusk spe- cies, 1.e., Ariolimax columbianus (Gould, 1851), Prophy- saon andersoni (Cooper, 1872), Prophysaon vannattae (Pilsbry, 1948), and Megomphix hemphilli (Binney, 1879) also evidenced ingestion of both plant and fungal mate- rial. The relative importance of plant, fungal, and other ma- terial in the diets of these two slug species warrants fur- ther investigation; however, P. coeruleum and P. dubium in this region are clearly at least partially mycophagous, and especially so in the fall. Most of the fungal species identified are mycorrhizal and hypogeous. Fungal fruiting bodies seemed to be targeted as food items, however fun- gal hyphae were also present in most samples. Spores seemed to be in good condition, and these slug species may be important vectors for spore dispersal of these for- est fungi (Kimmerer & Young, 1995). Future viability studies on the hyphal fragments in mollusk fecal pellets may indicate that dispersal of live hyphae may also be occurring. Acknowledgments. We thank T. Cozine, J. Harvey, and R. Kon- kle for assisting in collecting samples in the field, Julie Knu- rowski for help with fungal taxonomy, and the Roseburg District Bureau of Land Management for support in this study. This pro- ject was supported in part by grants from the USDI Oregon/ Washington Challenge Cost Share Program. Thanks also to Jim Trappe for review and comments on this manuscript. Literature Cited Butter, A. H. R. 1922. Slugs as mycophagists. Researches on Fungi 2:270—283. CASTELLANO, M. A., J. M. TRAPPE, Z. MASER & C. MASER. 1989. Key to Spores of the Genera of Hypogeous Fungi of North Temperate Forests with Special Reference to Animal My- cophagy. Mad River Press: Eureka, California 186 pp. CHATFIELD, J. E., 1967. Studies on food and feeding in some European land mollusks. Journal of Conchology 29:5—20. COLGAN, W. II, A. B. CAREY & J. M. TRAPPE. 1997. A reliable method of analyzing dietaries of mycophagous small mam- mals. Northwest Naturalist 78:65—69. FURNISH, J. L., T. E. BurKE, T. R. WEASMA, J. S. APPLEGARTH, N. L. DuNCAN, R. MONTHEY & D. Gowan. 1997. Survey protocol for terrestrial mollusk species from the Northwest The Veliger, Vol. 45, No. 3 Forest Plan, draft version 2.0. USDA Forest Service (Re- gions 5 and 6), and USDI Bureau of Land Management (Oregon, Washington, and California). vi + 79 pp. KIMMERER, R. W. & C. C. YouNG. 1995. The role of slugs in dispersal of the asexual propagules of Dicranum flagellare. The Bryologist 98(1):149-153. PALLANT, D. 1969. The food of the grey field slug (Agriolimax reticulatus (Muller)) in woodland. Journal of Animal Ecol- ogy 38:391-397. USDA Forest SERVICE, AND USDI BuREAU OF LAND MANAGE- MENT. 1994. Record of Decision for Amendments to the For- est Service and Bureau of Land Management Planning Doc- uments within the Range of the Northern Spotted Owl. [Portland, Oregon]: U.S. Department of Agriculture, Forest Service; U.S. Department of Interior, Bureau of Land Man- agement. The Taxonomic Status of the Freshwater Snail Antillobia margalefi Altaba, 1993, from Hispaniola (Hydrobiidae: Cochliopinae) Fred G. Thompson Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA A recent paper (Altaba, 1993) described a freshwater snail from Lago de Enriquillo, Dominican Republic, as Antillobia margalefi, new genus and new species. The description is based on “‘very few specimens,”’ of which two males and two females were dissected. The speci- mens were preserved unrelaxed in the field in 10% for- malin and later transferred to 70% ethanol. They were highly contracted and distorted within their shells because of how they were preserved. The holotype and two fig- ured paratypes were deposited in the Museu de la Natur- alesa de les Illes Balears, Ciutat de Mallorca. A third figured paratype remained in the author’s collection. Oth- er uncited and unfigured paratypes were said to be in the Florida Museum of Natural History, but they cannot be located. Altaba (1993) used 27 character-states to compare An- tillobia with three closely related genera, Spurwinkia Da- vis, Mazurkiewicz & Mandracchia, 1982, Heleobia Stimpson, 1865, and Heleobops Thompson, 1968 (Coch- liopinae) and with the distantly related genus Hydrobia Hartmann, 1821 (Hydrobinae). Anatomical data for the four genera were taken from the literature, and were based on abundant specimens that had been properly re- laxed and fixed prior to preservation. The 27 character- states are as follows. 1. Hypertrophied ciliation of left tentacle simple (0), grouped in transversal bands (1), or forming subdivided transversal bands (2). Mantle edge with (0) or without (1) pallial tentacle. N Notes, Information & News ~ Osphradium annular (0) or voluted (1). 4. Posterior caecum of stomach deep and bent laterally (0), or median and shallow (1), or altogether absent (2). 5. Typhosole d and the dorsal groove it defines absent (0) or present (1). 6. Opening of anterior digestive gland absent (0), anterior (1), posterior (2), or fused with that of posterior digestive gland (3). 7. Gastric shield small (0) or large (1). 8. Ovary lobes few and wide (0), or few globose (1), or several wide (2), or numerous digitiform (3). 9. Anterior end of ovary covering stomach (0) or posterior to it (1). 10. Posterior end of ovary reaching close to posterior end of body (0), or placed far from it (1). 11. Ovary entering ventral sperm canal (0) or posterior pallial oviduct (1). 12. Oviduct coiled (0), or just bent over itself (1). 13. Pallial oviduct divided into two (0) or three (1) distinct re- gions. 14. Albumen gland straight (0) or bent on itself (1). 15. Lobes of albumen gland small (0), or large and columnar (1). 16. Spermathecal duct absent (0) or present (1). 17. Spermathecal duct coalesced with (1) or independent of (2) oviduct. 18. Spermathecal duct long (1) or short (2). 19. Duct of seminal receptacle stemming off of oviduct (0), con- nected to it by a short sperm duct (1), or through a simple orifice where they are oppressed (3). 20. Uneverted penis straight (0) or coiled (1). 21. Terminal papilla on the verge simple (0) or eversible (1). 22. Surface of verge smooth (0), or creased and glandular (1). 23. Globose glands on convex side of verge absent (0) or present (1). 24. Stalked glands on convex side of verge absent (0), short (1), or cuplike (2). 25. Anterior concave side of verge with a non-glandular lobe (O), or with a lobe carrying discrete glands along its edge (1), or with a lobe of glandular tissue (2), or without such a lobe (3). 26. Subterminal ciliation on the verge present (0) or absent (1). 27. Longitudinal groove on verge absent (0) or present (1). Six of the character-states used by Altaba are non-var- iable within the four cochliopine genera and have no comparative value except to separate the Cochliopinae from the Hydrobiinae. These are character-states 2, 5, 7, 11, 13, and 16. Eight character-states also have little comparative value because of the manner in which the specimens were pre- served and how these character-states were interpreted. For example, the head is illustrated as though it were in a natural relaxed condition (Altalba: 1993, fig. 3), yet if the specimens had been killed unrelaxed in formalin, the head and tentacles would have been severely contracted. Surely the head as illustrated is an interpretation and not an actual depiction. Interpretations of eight character- states used to separate Antillobia from Heleobops are questionable for the same reason. These include: (3) the Page 265 shape of the osphradium, (4) the size and shape of the posterior caecum of the stomach, (6) the opening of the digestive gland, (14) the shape of the albumen gland, (22) the texture of the penis surface, and (24) having unstalked or weakly stalked glands along the convex side of the penis. Antillobia is described as having discrete glands along the anterior concave side of verge (25), The depic- tion of these structures in Altabla: 1993, fig. 9 is non- convincing as glands and not as contracted folds of skin. Antillobia is said to have a longitudinal groove on [the dorsal surface of] the penis (27). This also is an artifact of preservation due to intense contraction and partial des- iccation of the animals caused by having been killed and fixed in formalin. Five character-states pair Antillobia with Heleobops, and separate the two from Spurwinkia and Heleobia. These are: the ciliation pattern on the tentacles (1-1), the anterior extent of the ovary over the stomach (9-1), the weak coiling of the oviduct (12-1), the short spermathecal duct (19-2), and the presence of globose glands along the convex side of the verge (23-1). Five-character states group Antillobia and Heleobops with Heleobia, and separate the three from Spurwinkia. These are: the independent spermathecal duct from the oviduct (17-2), the short spermathecal duct (18-2), the coiled uneverted penis (20-1), the simple terminal papilla on the verge (21-0), and the absence of subterminal cil- iation on the verge (26-1). Three character-states are left to separate Antillobia from Heleobops. These are (8) the size and number of the ovary lobes, (10) the location of the ovary within the digestive gland, and (15) the size and shape of the albu- men gland lobes. These three characters hardly constitute a basis for separating genera, especially considering that the data are based only on two inadequately preserved specimens. Two taxonomic questions are posed by the description of Antillobia margalefi. One question is the status of the genus name Antillobia, and the other question is the status of the species name margalefi. The description and illus- trations given for Antillobia pertain to two previously known species, Pyrgophorus coronatus bermudezi (Aguayo, 1947) and Heleobops clytus Thompson & Her- shler, 1991. Both are common species about Lago de En- riquillo, and they are the only two hydrobiids known to occur there. Heleobops clytus is oviparous with the uterus unmodified into a brood pouch, and the verge (penis) bears unstalked apocrine glands along its outer curvature. Pyrgophorus coronatus bermudezi is viviparous, with a brood-pouch containing developing juveniles, and the verge bears elongate papillae along the outer curvature and elsewhere, as is typical for Pyrgophorus (Hershler & Thompson, 1992:90—-91). The female reproductive anat- omy of Antillobia, as described and figured by Altaba, lacks a brood pouch with developing embryos and juve- niles (Altaba, 1993, fig. 4), as is typical for Heleobops. Page 266 The penis, as described by Altaba, has unstalked apocrine glands along its outer curvature. The anatomical data pre- sented by Altaba for Antillobia pertains to Heleobops. Under normal circumstances, the anatomical informa- tion would resolve the identity of A. margalefi, but shell features add confusion. The designated holotype is a “large” intact specimen in alcohol (approx. 2.4 mm long and consisting of five whorls). Shells of H. clytus and P. c. bermudezi are very similar to each other, and some- times it is not possible to separate the shells of immature specimens (see Thompson & Hershler, 1991:674). The shell length and number of whorls of the holotype suggest a juvenile male of either species. Both species are sexu- ally dimorphic in size, with females being much larger than males with the same number of whorls. Females 2.4 mm in length of either species typically have four or few- er whorls. The description of the shell seems to be a com- posite of characters from two species. Antillobia marga- lefi is described as having slightly swollen whorls with a moderately deep suture. The periostracum is pale ochre in color and has numerous exceedingly faint, thin, irreg- ularly spaced spiral striations. The peristome is continu- ous across the parietal margin. The traits in italics are typical for P. c. bermudezi. The other traits are typical for H. clytus. The figure of the holotype of A. margalefi (Altaba, 1993, fig. 1) is most similar in appearance to typical male P. c. bermudezi. However, the specific iden- tity cannot be resolved unless the holotype is dissected, which undoubtedly would require destroying the shell. Under the circumstances, the name Antillobia margalefi must be considered a synonym of Pyrgophorus coronatus bermudezi because of the holotype shell, even though the anatomical data given by Altaba pertain to Heleobops cly- Tus. The following taxonomic changes are in order. (1) The species name Antillobia margalefi Altaba, 1993, is a subjective junior synonym of Pyrgophorus co- ronatus bermudezi (=Lyrodes coronatus bermudezi Aguayo, 1947). (2) The genus name Antillobia Altaba, 1993, is a sub- jective junior synonym of Pyrgophorus Ancey, 1888, be- cause its type species is a Pyrgophorus. (3) The anatomical data presented by Altaba, which pertain to Heleobops clytus, do not justify separation of Heleobops clytus Thompson & Hershler, 1991, as a genus distinct from Heleobops docimus Thompson, 1968, the type species of Heleobops. Synonymies for the two spe- cies are as follow. Pyrgophorus coronatus bermudezi (Aguayo, 1947) Lyrodes coronatus bermudezi Aguayo, 1947:81—83; fig. 1 (holotype), fig. 2 (paratypes). Pyrgophorus coronatus bermudezi (Aguayo), Thompson & Hershler, 1991: 679; fig. 4. Hershler & Thompson, 992292: Antillobia margalefi Altaba, 1993: 73, 90; fig. 1. The Veliger, Vol. 45, No. 3 Type locality: Lyrodes corontus bermudezi: Reptblica Dominicana, Provincia de Barahona, Lago Enriquillo, cerca de Mella (now in Provincia Independencia), Pleis- toceno (?). Holotype: Museo Poey, no. 12146. Antillobia margalefi: Lago Enriquillo (sic), Dominican Republic. Holotype: Museu de la Naturalesa de les Illes Balears, Ciutat de Mallorca, uncatalogued. Distribution: Known only from the vicinity of Lago de Enriquillo. Other forms of Pyrgophorus coronatus are found elsewhere on Hispaniola. Specimens examined: DOMINICAN REPUBLIC. JIn- dependencia Prov.: spring 2 km ESE of Duverge (UF 175165); spring, 6 km WNW of Duverge (UF 174885, preserved UF 252046); spring, Boca de Cachén (UF 175215); spring, 4 km E of La Descubierta (preserved UF 252048); spring, I km W of Las Baitoas (UF 174889). Heleobops docimus Thompson & Hershler, 1991 Heleobops clytus Thompson & Hershler, 1991: 672-674; fig. 3. Hershler & Thompson, 1992; Malacological Review, Suppl. 5:60; figs. 34, 35a. Antillobia margalefi (in part) Altaba, 1993: 73, 90; figs. 3— 10. Type locality: A spring 2 km ESE of Duverge, Indepen- dencia Prov., Dominican Republic. Holotype: UF 175170. Distribution: At present known only from the environs of Lago de Enriquillo and the Laguna del Rincon, Do- minican Republic. All of these stations are in the cul de sac that extends from Barahona, Dominica Republic to Port-au-Prince, Haiti. Heleobops is widespread elsewhere on Hispaniola, but the taxonomy of these other popula- tions has not been resolved yet. Specimens examined: HISPANIOLA. DOMINICAN REPUBLIC. Independencia Prov.: spring 2 km ESE of Duverge (holotype, paratypes UF 135428, 174880, pre- served UF 93973); Laguna Del Rincon, 6 km. WNW Ca- bral (UF 175203, UF 174884, preserved UF 93976); spring 5 km WNW Duverge (UF 174881, UF 175202): spring, Boca de Cachon (UF 174891, preserved UF 93974); spring 1 km W of Las Baitoas (UF 174887, pre- served UF 175199); spring along N shore Lago de En- riquillo, 4 km E La Descubiertia (UF 174894, preserved UF 175201); Laguna La Sequia, 1 km S of Augostura (UF 45687); spring, 4 km ENE Neiba (UF 174896, pre- served UF 175200). Lago de Enriquillo is fed by seasonal rivers and by numerous springs along the south, west, and north shores. The two hydrobiid species are abundant on vegetation in springs and spring-fed streams that drain into the lake. The more saline environ of the lake is nearly devoid of aquatic angiosperms, and snails are very sparse or absent there. Notes, Information & News Literature Cited AGuAyo, C. G. 1947. Notas y variadades (VIII). Revista de La Sociedad Malacologica “‘Carlos de la Torre,” 5:81—83. ALTABA, C. R. 1993. Description and relationships of a new brackish-water snail genus (Gastropoda: Hydrobiidae: Lit- toridininae) from Hispaniola. Zoological Journal of the Lin- nean Society of London 107:73-—90; figs. 1-11. HERSHLER, R. & EF G. THOMPSON. 1992. A revision of the aquatic gastropod family Cochliopinae (Prosobranchia: Hydrobi- idae). Malacological Review, Supplement 5:1—140. THompson, FE G. 1968. The Aquatic Snails of the Family Hydro- biidae of Peninsular Florida. University of Florida Press: Gainesville. 268 pp. THompson, FE G. & R. HERSHLER. 1991. New hydrobiid snails (Mollusca, Gastropoda: Prosobranchia: Truncatelloidea) from North America. Proceedings of the Biological Society of Washington 104:669—683. Predation of Water Bug Sphaerodema rusticum on the Freshwater Snails Lymnaea (Radix) luteola and Physa acuta G. Aditya and S. K. Raut Ecology and Ethology Laboratory, Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata - 700019, India The freshwater snails Lymnaea (Radix) luteola Lamarck, 1822, and Physa acuta Draparnaud, 1805, are found side by side in nature where they are occurring. It is practi- cally impossible to distinguish them at a glance. The wa- ter bug Spherodema rusticum Fabr. preys upon both the snail species (Raut et al., 1988; Aditya & Raut, in press). Since the prey individuals are of similar type with respect to their shell contour and size, the aim of this study was to determine whether the water bug Spherodema rusticum has preference for either of the species and, if so, whether the water bug is able to select the individuals belonging to the preferred prey species when both the prey species are found together. The snail L. (R.) luteola is involved in the spread of worm diseases in man and animals (Raut, 1986, 1991; Subba Rao, 1989; Mukhopadhyay, 1991; Sri- vastava, 1991; Subba Rao & Mitra, 1991), and P. acuta is causing serious problems in sewage purification plants (Macha, 1971). Attempts are being made to control these snails through the use of biological agents. Therefore, the findings of the present study will enable us to gain some knowledge on the effective use of the water bug S. rus- ticum to control the snails L. (R.) luteola and P. acuta. Materials and Methods A large number of L. (R.) luteola and P. acuta 6—7 mm in shell length were collected from the municipality Page 267 drains in Kolkata, India. The adult morphs of the water bug S. rusticum were also collected from the same drain simultaneously. They were kept in the laboratory in pond water, in plastic containers. The snails were fed with let- tuce regularly for a period of 7 days. The water bugs were allowed to feed on the snails kept in the containers. After 1 week, the following experiments were performed to note the rate of predation of S. rusticum on the prey in- dividuals supplied. Experiment I. 40 L. (R.) luteola were exposed to an adult S. rusticum. 40 P. acuta were exposed to an adult S. rusticum. Experiment III. 40 prey individuals (20 L. (R.) luteola and 20 P. acuta) were exposed to an adult S. rusticum. Experiment II. The same-sized L. (R.) luteola and P. acuta were al- most equal in weight. Experiments were carried out in plastic containers, each 25 cm in diameter and 8 cm in depth, containing 2.5 L pond water. All the experiments were carried out for 7 consecutive days. Experiments with the single prey species were repeated three times, while those with the combination of two prey species were repeated six times. Data were collected on the number of snails consumed completely (except the shell) and partially, at the end of each 24 hour period. The water in the container was re- placed by fresh pond water, and the prey snail individuals, as per specification were released into the container every 24 hours. In all cases, mean and standard error (+ SE) were calculated. Analysis of variance (ANOVA) was ap- plied (Campbell, 1989) to ascertain whether the rate of predation differed significantly with the prey species, sin- gly, or in combinations of the two, or not. Results Experiment I In 21 trials the adult S. rusticum killed a total of 262 L. (R.) luteola. Of these, 179 (68.32%) and 83 (31.68%) were devoured completely and partially, respectively, by the water bug. The water bug killed 8—18 (average 12.48 + 0.65) individuals per day. The number of completely and partially consumed individuals ranged from 6-10 (average 8.52 + 0.31) and 0-9 (average 3.96 + 0.51) per day (Figure 1), respectively. Experiment II The water bug killed a total of 217 P. acuta in 21 trials in 7 days. The number of completely and partially de- voured individuals was 82 (37.79%) and 135 (62.21%), respectively. The daily rate of predation ranged from 7— 16 (average 10.33 + 0.56). Of these, O-10 (average 3.9 + 0.45) and 2—14 (average 6.43 + 0.7) individuals were Page 268 20 OL. (R.) luteola AP. acuta 15 DIL. (R.) luteola + P. acuta Prey individuals (in number) Killed Consumed completely | Consumed partially Figure 1. The number (mean + SE) of prey individuals be- longing to L. (R.) luteola and P. acuta killed, completely con- sumed, and partially consumed per day (24 hours) by an adult S. rusticum (40 individuals of each prey species were supplied separately for 24 hours). devoured completely and partially, respectively (Figure 1). Experiment III Irrespective of prey species, a total of 405 individuals were killed by the water bug in 42 trials. Of these, 295 (72.84%) and 110 (27.16%) individuals were devoured completely and partially, respectively. The daily rate of predation, irrespective of prey species, ranged from 4-19 (average 9.64 + 0.55), and the number of completely and partially consumed individuals ranged from 4—14 (aver- age 7.02 + 0.4) and O-11 (average 2.62 + 0.28) per day, respectively (Figure 1). Analysis of the data revealed that the water bug killed 263 L. (R.) luteola and 142 P. acuta in 42 trials. Of the 263 L. (R.) luteola, 229 (87.07%) and 34 (12.93%) were consumed completely and partially, respectively. The wa- ter bug consumed 66 (46.48%) and 76 (53.52%) P. acuta completely and partially, respectively. A comparative ac- count of the rate of kill and consumption, completely and/ or partially by the water bug is shown in Figure 2. ANOVA tests clearly revealed no significant difference in the rate of predation in terms of killing of the prey individuals per day by S. rusticum between the prey snail species L. (R.) luteola and P. acuta. However, the rate of complete consumption of the prey individuals by the predator differs significantly (P < 0.01) with the prey species. Similarly, the difference in partially fed individ- The Veliger, Vol. 45, No. 3 OL. (R.) luteola P. acuta Prey individuals (in number) wn Killed Consumed completely Consumed partially Figure 2. The number (mean + SE) of L. (R.) luteola and P. acuta killed, completely consumed, and partially consumed by an adult S. rusticum per day (24 hours) when 20 L. (R.) luteola and 20 P. acuta were supplied together. uals between the prey species is statistically significant (P < 0.01). In L. (R.) luteola the difference in the number of completely and partially consumed individuals is sta- tistically significant (P < 0.01). In the case of P. acuta, however, such differences are insignificant. The water bug, while exposed to both the prey species, killed a varying number of individuals with respect to species. Such variations are statistically significant (P < 0.01) as is evident from the results of ANOVA tests. Also, the variations in the rate of completely consumed (P < 0.001) and partially consumed (P < 0.05) prey individuals are statistically significant with respect to the prey species concerned. Discussion The water bug S. rusticum killed on an average 12.48 and 10.33 L. (R.) luteola and P. acuta, respectively, when they were supplied separately in equal numbers daily. Al- though the rate of killing of the prey snails varied with the treatment, such variations are statistically insignifi- cant. Therefore, it appears that both species of prey snail were almost equally acceptable to the water bug S. rus- ticum. However, it appears that S. rusticum 1s sensitive to the quality of the food materials of the snail species con- cerned. It consumed 68.27% and 37.75% of the captured (killed) L. (R.) luteola and P. acuta completely, respec- tively, daily when predation was confined to the individ- uals belonging to a single prey species. It is difficult to accept the idea that the quantity of food present in an individual P. acuta is double the amount contained in a same-sized (equal weight) L. (R.) luteola. If that were the Notes, Information & News case, why did the predator feed on 62.25% P. acuta par- tially? In the case of predation on both prey species, S. rusticum killed 6.26 L. (R.) luteola and 3.38 P. acuta per day. Since there were 40 prey individuals, 20 L. (R.) lu- teola and 20 P. acuta, the water bug would have con- sumed only L. (R.) luteola to satisfy its needs. In reality, it killed 6.26 and 3.38, and consumed 5.45 and 1.57 L. (R.) luteola and P. acuta individuals completely, respec- tively, daily. As the water bug consumed 1.57 P. acuta in contrast to 5.45 L. (R.) luteola completely, the possi- bility of selection of the prey individuals by S. rusticum prior to capture is very remote. If that were the case, there would have been no chance of victimization of P. acuta by S. rusticum. The results show that S. rusticum was reluctant to swallow the flesh of P. acuta. Therefore, it is not expected that the water bugs would spend energy unnecessarily to capture and handle P. acuta. In reality this did occur. Thus, it seems that the water bug was unable to recognize the prey individuals with respect to the species under reference. This again raises the question of the swallowing of the snail P. acuta. If P. acuta were captured by mistake, then it would be expected that the water bug would refuse the same, when it became known because of taste that the prey was not L. (R.) luteola. But we have cases where S. rusticum devoured the flesh of P. acuta completely. However, this was not a case of parallel choice of the prey individual P. acuta with re- spect to L. (R.) luteola, but more likely a feeding choice to satisfy hunger and ensure survival. However, whatever the degree of preference for the prey snails, L. (R.) luteola and P. acuta, the water bug S. rusticum would prove effective in killing both prey spe- cies at an almost equal rate in a natural population, be it a single prey species population or a mixed population of both species. Therefore, consideration should be given to employing S. rusticum to control the snails L. (R.) luteola and P. acuta with a view to minimizing the hazards as- sociated with these species (Macha, 1971; Raut, 1986; Subba Rao, 1989; Srivastava, 1991). Acknowledgements. We thank the Head of the Department of Zoology, University of Calcutta, for the facilities provided. Literature Cited ApityA, G. & S. K. Raut. In press. Predation potential of the water bugs Sphaerodema rusticum on the sewage snails Phy- sa acuta. Memorias do Instituto Oswaldo Cruz. CAMPBELL, R. C. 1989. Statistics for Biologists. 3rd ed. Cam- bridge University Press: Cambridge. xvii + 446 pp. Macnwa, S. 1971. Kultureinflusse auf die Molluskenfauna. Tschech casop Acta Musci Silesiae, Ser. A. Sciences natu- relles 20:121—146. Mukuopapuyay, B. 1991. Ecology of the water bug Sphaero- dema rusticum Fabr. Ph. D. Thesis, University of Calcutta, India. Raut, S. K. 1986. Snails and slugs in relation to human diseases. Environment and Ecology 4:130—138. Raut, S. K. 1991. Laboratory rearing of medically and econom- Page 269 ically important molluscs. Pp. 79-83 in Snails, Flukes and Man. Zoological Survey of India: Calcutta. 116 pp. Raut, S. K., T. C. SAHA & B. MUKHOPADHYAY. 1988. Predacious water bugs in the control of vector snails. Bicovas 1:175— 185. SRIVASTAVA, C. B. 1991. Schistosomes and schistosomiasis with particular reference to India. Pp. 103-111 in Snails, Flukes and Man. Zoological Survey of India: Calcutta. 116 pp. SuBBA Rao, N. V. 1989. Freshwater Molluscs of India. Hand- book. Zoological Survey of India: Calcutta. xxiii + 289 pp. SUBBA RAO, N. V. & S.C. Mitra. 1991. Systematics and ecology of freshwater gastropods of parasitological importance. Pp. 55-66 in Snails, Flukes and Man. Zoological Survey of In- dia: Calcutta. 116 pp. Two Genera of North American Freshwater Snails: Marstonia Baker, 1926, Resurrected to Generic Status, and Floridobia, New Genus (Prosobranchia: Hydrobiidae: Nymphophilinae) Fred G. Thompson! and Robert Hershler? ' Division of Malacology, Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611-7800, USA ? Department of Systematic Biology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560-0118, USA Herein we recognize two genera of North American freshwater snails of the hydrobiid subfamily Nympho- philinae. One genus is resurrected from the synonymy of Pyrgulopsis Call & Pilsbry, 1886, while the other is new- ly proposed to accommodate species from the eastern United States previously placed in the genus Cincinnatia Pilsbry, 1891. Baker (1926) proposed Marstonia as a subgenus of Amnicola Gould & Haldeman, 1840, containing A. Jus- trica Pilsbry, 1890. Subsequently Baker (1928) added seven other species (all from northeastern North America) to this group, all of which are either currently placed in other genera or are fossils that are not readily assignable to genus. Berry (1943) showed that the penes of Amni- cola and Marstonia differ in terms of internal ducts (and other features), and Morrison (1949) implied that these taxa should be placed in separate subfamilies of Hydro- biidae on this basis. Thompson (1970) redefined Mar- stonia and restricted it to the type species and one (new) species from the southeastern United States. Thompson (1977) subsequently expanded Marstonia to include six other eastern North American species which he described in detail. He noted the close morphological similarity be- tween Marstonia and eastern species of Pyrgulopsis, but continued to recognize these as separate genera pending Page 270 The Veliger, Vol. 45, No. 3 study of the poorly known, extinct type species of the latter, P. nevadensis (Stearns, 1883). Hershler & Thomp- son (1987) studied resuscitated dried material of this western species, showed that its penis is closely similar to that of Marstonia, and synonymized the latter with Pyrgulopsis largely on this basis. However, a subsequent study showed that eastern North American species as- signed to Pyrgulopsis are strongly differentiated morpho- logically from western congeners (Hershler, 1994) and has led us to re-evaluate the status of Marstonia and again recognize it as a distinct genus. Marstonia Baker, 1926 Marstonia Baker, 1926:195. Diagnosis: Eastern North American nymphophilines with ovate- to elongate-conic shells. The penis bears a small terminal lobe. The penial filament is variably sized. The penial ornament consists of a terminal gland and some- times a ventral gland. Marstonia is distinguished from other nymphophilines in that the oviduct and bursal duct join well in front of the posterior pallial wall (Hershler, 1994:fig. 5C). Marstonia is further distinguished from Pyrgulopsis by the more coarsely pitted protoconch sculpture, incomplete inner shell lip across the parietal wall, banded (as opposed to diffuse) pattern of mantle pigmentation, narrowly vertical oviduct coil, and bursal duct largely or entirely imbedded in (as opposed to su- perficial to) the albumen gland (Hershler, 1994). Type species: Amnicola lustrica Pilsbry, 1890 (original designation). Other species included: Marstonia agarhecta Thomp- son, 1970; Marstonia arga Thompson, 1977; Marstonia castor Thompson, 1977; Marstonia comalensis (Pilsbry & Ferriss, 1906) (originally Amnicola comalensis Pilsbry & Ferriss, 1906); Marstonia halcyon Thompson, 1977; Marstonia letsoni (Walker, 1901) (originally Amnicola letsoni Walker, 1901); Marstonia ogmorhaphe Thomp- son, 1977; Marstonia olivacea (Pilsbry, 1895); Marstonia ozarkensis (Hinkley, 1915) (originally Pyrgulopsis ozar- kensis Hinkley, 1915); Marstonia pachyta Thompson, 1977; Marstonia scalariformis (Wolf, 1869) (originally Pyrgula scalariformis Wolf, 1869). Distribution: Eastern North America from south-central Texas to the Atlantic Coastal Plain. Remarks: As circumscribed herein, Marstonia includes species that Thompson (1977) previously allocated to the genus, and other eastern species that were previously placed in Pyrgulopsis (Hershler, 1994). We also transfer Amnicola comalensis to Marstonia based on our unpub- lished studies which show this species to conform mor- phologically to this genus. Cincinnatia Pilsbry, 1891, was established as a sub- genus of Amnicola to include Paludina cincinnatiensis Anthony, 1841 (a synonym of Paludina integra Say, 1821). Baker (1928) elevated Cincinnatia to full generic status, and Thompson (1968) expanded it to include 11 species which share a simple conical shell and a complex pattern of penial glandular ornament. Hershler & Thomp- son (1996) showed that the type species, C. integra, uniquely has two female bursal ducts; other species placed in Cincinnatia share a completely different female genitalic groundplan (Davis & Mazurkiewicz, 1985; Her- shler & Thompson, 1996; Thompson, 2000; Hershler, un- published data). Based on these observations, we restrict Cincinnatia to its type species and erect a new genus for other species from Florida and Maine. We propose that this genus be named for its center of diversity. Floridobia Thompson & Hershler, gen. nov. Diagnosis: Eastern American nymphophilines with ovate-conic shell. The penis has a large terminal lobe and a short filament. The penial ornament consists of large, crescent-shaped terminal and ventral glands, one or two narrow glands on the filament, and dorsal glands corre- sponding to Dg 1-3 (sensu Hershler, 1994). Additional glands on the dorsal and ventral surface are variably pre- sent and developed. Floridobia differs from all other North American nymphophilines in that females have a second, small anterior seminal receptacle (Thompson, 2000:figs. 23, 24). Floridobia further differs from Cin- cinnatia in that the dorsal glandular fields on the penis are not extensively fused; the bursa copulatrix is ovate or pyriform (but not cylindrical) and considerably overlaps the posterior end of the albumen gland; and there is only a single bursal duct which is superficial to or shallowly imbedded within the albumen gland. Type species: Amnicola floridana Frauenfeld, 1863. Other species included: Floridobia alexander (Thomp- son, 2000) (originally Cincinnatia alexander Thompson, 2000); Floridobia fraterna (Thompson, 1968) (originally Cincinnatia fraterna Thompson, 1968); Floridobia heli- cogyra (Thompson, 1968) (originally Cincinnatia heli- cogyra Thompson, 1968); Floridobia leptospira (Thomp- son, 2000) (originally Cincinnatia leptospira Thompson, 2000); Floridobia mica (Thompson, 1968) (originally Cincinnatia mica Thompson, 1968); Floridobia mon- roensis (Dall, 1885) (originally Bythinella monroensis Dall, 1885); Floridobia parva (Thompson, 1968) (origi- nally Cincinnatia parva Thompson, 1968); Floridobia petrifons (Thompson, 1968) (originally Cincinnatia pe- trifons Thompson, 1968); Floridobia ponderosa (Thomp- son, 1968) (originally Cincinnatia ponderosa Thompson, 1968); Floridobia porteri (Thompson, 2000) (originally Cincinnatia porteri Thompson, 2000); Floridobia van- hyningi (Vanatta, 1934) (originally Lyogyrus vanhyningi Vanatta, 1934); Floridobia wekiwae (Thompson, 1968) (originally Cincinnatia wekiwae Thompson, 1968); Flor- Notes, Information & News Page 271 idobia winkleyi (Pilsbry, 1912) (originally Amnicola winkleyi Pilsbry, 1912). Distribution: Eastern United States. Numerous species occur in Florida, while one congener (F. winkleyi) lives along coastal Maine. Etymology: The name Floridobia (f.) is derived from the name of the State of Florida plus the Classical Greek Bios, meaning life. The name is feminine in keeping with the usual practice for diminutive creatures. Literature Cited BAKER, FC. 1926. Nomenclatural notes on American fresh water Mollusca. Transactions of the Wisconsin Academy of Sci- ences, Arts, and Letters 22:193—205. BAKER, E C. 1928. The Fresh Water Mollusca of Wisconsin. Part I. Gastropoda. Wisconsin Academy of Sciences, Arts, and Letters: Madison. 507 pp., 28 pls. Berry, E. G. 1943. The Amnicolidae of Michigan: distribution, ecology, and taxonomy. Miscellaneous Publications, Muse- um of Zoology, University of Michigan 57:1—68, 9 pls. Davis, G. M. & M. MAzurktewicz. 1985. Systematics of Cin- cinnatia winkleyi (Gastropoda: Hydrobiidae). Proceedings of the Academy of Natural Sciences of Philadelphia 137:28— 47. HERSHLER, R. 1994. A review of the North American freshwater snail genus Pyrgulopsis (Hydrobiidae). Smithsonian Contri- butions to Zoology 554:1-115. HERSHLER, R. & E G. THompson. 1987. North American Hydro- biidae (Gastropoda: Rissoacea): redescription and systematic relationships of Tryonia Stimpson, 1865 and Pyrgulopsis Call and Pilsbry, 1886. The Nautilus 101:25—32. HERSHLER, R. & E G. THOMPSON. 1996. Redescription of Palu- dina integra Say, 1821, type species of genus Cincinnatia (Gastropoda: Hydrobiidae). Journal of Molluscan Studies 62:33-55. Morrison, J. P. E. 1949. The cave snails of eastern North Amer- ica. Annual Report of the American Malacological Union for 1948:13-15. THOMPSON, FE G. 1968. The Aquatic Snails of the Family Hydro- biidae of Peninsular Florida. University of Florida Press: Gainesville. 268 pp. THompson, E G. 1969 [1970]. Some hydrobiid snails from Geor- gia and Florida. Quarterly Journal of the Florida Academy of Sciences 32:241-265. THompson, F G. 1977. The hydrobiid snail genus Marstonia. Bulletin of the Florida State Museum, Biological Sciences 3:113-158. THompson, E G. 2000. Three new freshwater snails of the genus Cincinnatia from peninsular Florida (Prosobranchia, Hydro- biidae). Walkerana 11:55-73. f iy i — 1 ae Ma ” f ' i f j i i - 1 te i i | ; | ! S | i fi} | | il i} . 1 i ih} | | Hi | i} | } st aN ‘ hein { v { : Fie Cha | ; 4} | ‘ ie Caan If ‘ ‘ | | ; By tact ee | r Nise | ‘ | ‘ | , , | - G i w) i fh , : ol | 5) ae * J } | ‘ a f , eh = | wer at ey ana V4 x ©: ptr ' “ i (sae aay i y ; \ 4 =| f bay i Mh: i ‘ | a: Information for Contributors Manuscripts Manuscripts must be typed, one side only, on A4 or equivalent (e.g., 842” X 11”) white paper, and double-spaced throughout, including references, figure legends, footnotes, and tables. All margins should be at least 25 mm wide. Text should be ragged right (i.e., not full justified). 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NOTES, INFORMATION & NEWS Kalidos griffithshauchleri, sp. nov., Madagascar’s largest helicarionid snail (Pulmonata) KENNETH: G EMBERTON iis ce actin ala, nits, 108 A cen aioe cer nt ar ETS ee Fungi and other items consumed by the blue-gray taildropper slug (Prophysaon coeruleum) and the papillose taildropper slug (Prophysaon dubium) REX McGRAW, NANCY DUNCAN, AND EFREN CAZARES ........00000 ce eeceeeeee The taxonomic status of the freshwater snail Antillobia margalefi Altaba, 1993, from Hispaniola (Hydrobiidae: Cochliopinae) FREDIG: HOMPSONG ctor hie Siena chee) rye Pree peneiate necee eee ae Predation of water bug Sphaerodema rusticum on the freshwater snails Lymnaea (Radix) lute- ola and Physa acuta GADITYA AND SY KO pRAUWIE) 2.1575 2 silafe cos) 10 cm. Many of the tagged mussels disappeared over the course of the 3—4 week monitoring intervals, most likely due to wave dislodgment. The frequency of mussel disappearance was generally similar inside and outside of patches and between habitats, with the exception of a higher disappearance rate in October than July 1995 for mussels in tidepools but not on emergent rock. This study demonstrates that mussel patches on a wave-exposed shore are dynamic, with movements constantly rearranging individuals within patches, and high rates of loss of individuals, presumably from wave disturbance. INTRODUCTION Mussels form patches or large beds on rocky shores, and often are major occupiers of space in the intertidal zone (Seed & Suchanek, 1992). Although mussels generally are thought of as sessile, they are not permanently at- tached to the substratum. Young postlarval mussels can use byssal threads that increase hydrodynamic drag to drift in the water column (Sigurdsson et al., 1976; De Blok & Tan-Maas, 1977). Larger juvenile and adult mus- sels may disperse actively over short distances by crawl- ing, or passively over greater distances by wave dislodg- ment. Active dispersal by crawling generally has not been considered important in prior studies of intertidal mussel assemblages, although Mytilus edulis Linnaeus, 1758, within subtidal aggregations have been observed to con- stantly move and reorient themselves (Dolmer et al., 1994; Anthony & Svane, 1995). Mussels may be less mo- bile in the intertidal zone of wave-exposed shores, where they must attach firmly to the substratum to withstand wave forces, than in the subtidal zone. Nevertheless, even movements over small distances could greatly influence rates of growth and mortality if they change a mussel’s location within a patch or result in movement to a new patch. Mussels living in the center of groups generally experience reduced growth, but greater protection from * Current address: Institute of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, New Jer- sey, 08901, USA; email: hunt @imcs.rutgers.edu predation compared to individuals around the edge (Oka- mura, 1986). Living within an aggregation also shields mussels from hydrodynamic forces acting along the di- rection of flow (Denny, 1987) and is predicted to buffer individuals against rapid changes in temperature (Hel- muth, 1998). Studies have found a negative (Okamura, 1986; Newell, 1990; Svane & Ompi, 1993) or positive (Hunt & Scheibling, 2001a) relationship between mussel growth rate and patch size. Larger displacements of adult mussels are likely to oc- cur passively through dislodgment and redistribution by waves. Dislodgment by waves is a major cause of loss of mussels in the intertidal zone (e.g., Paine & Levin, 1981). Although some of the mussels dislodged by waves un- doubtedly die, others probably are redistributed to new patches. Adult mussels have been observed colonizing cleared areas on rocky shores (Paine, 1974; Wootton, 1993). At our study site in Nova Scotia, we found that most mussel colonists were >2 mm in shell length (Hunt & Scheibling, 1998b). Also, the greatest changes in mus- sel patch size usually occurred suddenly and often were associated with storms, suggesting that large mussels were dislodged and re-deposited by waves (Hunt & Scheibling, 2001a). In this study, we quantified rates of movement and dis- appearance of tagged mussels on a wave-exposed shore in Nova Scotia, Canada. Rates of movement were com- pared between habitats (tidepools and emergent rock), po- sitions (inside and outside of patches), seasons (summer and fall), and years. Mussels were tagged in situ to avoid disturbance of their attachment to the substratum. The Veliger, Vol. 45, No. 4 METHODS This study was conducted on an exposed rocky shore at Cranberry Cove (44°28'N, 63°56'W) near Halifax, Nova Scotia, Canada. The shore is composed of granite plat- forms and outcrops with occasional large boulders. There are numerous tidepools in irregular depressions along the shore, ranging from a few decimeters to over 10 m in maximum dimension. The shore is exposed to large southerly swells during fall and winter storms. Mussel assemblages at Cranberry Cove consist of a mixture of Mytilus trossulus Gould, 1850, and M. edulis: approxi- mately 65—80% of mussels in tidepools and on emergent rock are M. trossulus, the remainder consist of M. edulis and hybrids of the two species (Hunt & Scheibling, 1998b). M. trossulus and M. edulis cannot be distin- guished visually at the small size of the individuals at our study site. Most mussels are < 5 mm in shell length (SL): very few exceed > 20 mm (Hunt & Scheibling, 1998a). We investigated the mobility of mussels by tagging in- dividuals ~ 5 to 25 mm in shell length with numbered plastic bee tags (Steele & Brodie Ltd., Hampshire, Eng- land). These tags are small (2.6 mm diameter, 0.02 mm thickness) and lightweight (0.0014 g) and presumably have no measurable effect on movement of mussels. The same tags have been used to study swimming movements of juvenile scallops within a similar size range (Carsen et al., 1995). In August 1994, we tagged 15 individuals in each of two tidepools and two plots of emergent rock and monitored them for 2—3 weeks. In July and October 1995, we tagged 20 mussels in both a tidepool and an adjacent plot of emergent rock and monitored them for ~ 4 weeks. The mussels were tagged in situ after temporarily draining the water from the tidepools. We dried one shell valve on each selected mussel, cleaned it with acetone, and affixed a tag using cyanoacrylate glue. Mussels < 5 mm were not tagged because their small size made it difficult to attach a tag without gluing the valves shut. Tagged mussels were grouped into two categories of ini- tial position: in natural patches (at center or edge) and outside of them (alone or in a small group, or on top of the single layer of mussels in a patch). Mussels on top of a patch were considered to be outside because their fre- quencies of movement and disappearance were more sim- ilar to those of solitary mussels than to those in patches. We determined the location of each tagged mussel at 2— 10 day intervals by measuring the distances between the mussel and two reference bolts drilled into the rock. We converted these distances to x and y coordinates and trig- onometrically calculated the distance moved by a mussel between sampling dates from the coordinates for each date. These distances are minimum values, since mussels could have moved nonlinearly between sampling dates. We compared distances of movement between habitats, positions, and dates using ANOVA or t-tests, and the fre- quencies of movement and disappearance of mussels us- ing contingency tables (G-test). RESULTS The tagged mussels were mobile, although they moved infrequently and for short distances. In August 1994 and July 1995, 21 to 56% of mussels in patches and 67 to 86% of those outside of patches moved within 13-27 days (Figure 1). In October 1995, only 7—10% of mussels in patches and 43—66% of isolated mussels moved within 30 days (Figure 1). The percentage of mussels that moved did not differ significantly between tidepools and emer- gent rock during each monitoring interval (August 1994: in patches, G, = 2.87, P = 0:09; outside, G) = 0275. = 0.60: July 1995: in patches, G, = 1.44, P = 0.23; outside, G, = 0.07, P = 0.79; October 1995: in patches, G, = 0.11, P = 0.74; outside, G, = 0.56, P = 0.46). Mussels outside of patches in both habitats were signifi- cantly more likely to move than those in patches (habitats pooled; August 1994, G, = 6.66, P = 0.01; July 1995, G, = 10.48, P = 0.001; October 1995, G, = 11.49, P = 0.001). In 1995, a higher percentage of mussels in patches moved in July than in October (habitats pooled, G, = 4.93, P = 0.03), when wave heights were much greater (Hunt & Scheibling 2001b). The percentage of mussels outside of patches that moved did not differ significantly between these dates (habitats pooled, G, = 1.16, P = 0.28). Distances moved by tagged mussels were usually < 5 cm with a modal class of 1—2 cm, although six out of 68 individuals moved 10—49 cm (Figure 2). Distance moved during August 1994 and July 1995 did not differ signif- icantly between tidepools and emergent rock (August 1994, pooled across plots: F,,, = 1.20, P = 0.29; July 1995, F,5, = 0.84, P = 0.37; October 1995, outside mus- sels (there was insufficient data to include mussels in patches in the analysis): t; = 0.49, P = 0.64), or between mussels in patches and those outside (August 1994: F, 5, = 0.009, P = 0.93; July 1995, F, 55 = 0.008, P = 0.93), and there was no significant interaction between habitat and position (August 1994: F,,, = 0.93, P = 0.35; July 1995: Fy55 = 0.37, P = 0:55). During each of the monitoring intervals, some tagged mussels were not relocated. These mussels probably were dislodged by waves and moved beyond our limited sur- vey range of ~ 50 cm radius around their initial location. These disappearances were unlikely to have been tag losses because some tags from 1994 were still visible in 1995. Disappearances also were unlikely to have resulted from predation. Mussels eaten by the whelk Nucella la- pillus, the only abundant predator of mussels at this site (Hunt & Scheibling, 1998a, 2001a), remained attached to the substratum and were identified by the presence of a drill hole. We have occasionally observed crabs at Cran- ——EE H. L. Hunt & R. E. Scheibling, 2002 Page 275 August 1994 S 100 (7) me 75 oO (16) = BO = 25 2 (18) (20) LL = In Patches Outside Tidepool 5 Moved © Disappeared Emergent Rock = Moved & Disappeared Figure 1. July 1995 100 In Patches Outside —~ 100, October 1995 & > 75 8) m= 60 S 25 2 (14),(19) In Patches Outside Frequency (%) of movement and disappearance of tagged mussels in patches and those outside of them (alone or in small group, or on top of the single layer of mussels in a patch) in tidepools and on emergent rock in August 1994 (pooled across plots within a habitat) and July and October 1995. Frequency of movement was calculated as a percentage of the mussels that were tracked throughout a monitoring interval. Frequency of disappearance was calculated as a percentage of the total number of tagged mussels. Sample size is indicated in parentheses. berry Cove, but have found little evidence of crushed mussel shells indicative of crab predation. In August 1994 and July 1995, 10—22% of mussels in patches and 13-27% of those outside of patches disap- peared (Figure 1). In October 1995, when wave heights were greater, 42% and 17% of mussels in patches in ti- depools and on emergent rock, respectively, and 44-50% of mussels outside of patches in both habitats, disap- peared (Figure 1). The frequency of disappearance of mussels in July 1994 and August 1995 was too low to permit statistical comparisons of disappearance rate be- tween habitats and positions. In October 1995, the fre- quency of disappearance did not differ significantly be- tween tidepools and emergent rock, both for mussels in patches, (G, = 3.40, P = 0.065), and for those outside of patches (G, = 0.13, P = 0.72). The frequency of disap- pearance also did not differ significantly between mussels in patches and those outside (habitats pooled, G, = 2.38, P = 0.12). In 1995, the frequency of disappearance in tidepools was significantly greater in October than in July, both for mussels in patches (G, = 10.8, P = 0.002) and those outside (G, = 6.5, P = 0.011). In contrast, the frequency of mussel disappearance on emergent rock did not differ significantly between dates for mussels in patches (G, = 0.14, P = 0.710) and those outside (G, = 3.2, P = 0.07). These results indicate that the frequency of mussel disappearance was generally similar in and out- side of patches and between habitats, with the exception of a higher disappearance rate in October than July 1995 for mussels in tidepools but not on emergent rock. DISCUSSION It has long been recognized that Mytilus edulis detached from the substratum will crawl using their foot and byssal threads (e.g., Maas Geesteranus, 1942). However, most studies of mussels on hard substrates have recorded little mobility of undisturbed Mytilus. Our tagging study indi- cated that a significant proportion of mussels moved short distances. For example, 21—56% of mussels in patches in summer moved within 4 weeks. Some of these move- ments could have occurred by wave dislodgment rather than by crawling. In a study that examined mussels as a substrate for anemones, Anthony & Svane (1995) moni- tored movements of M. edulis in a subtidal mussel bed photographically. The frequency of movement of mussels in their study was higher (94% moved within 4 weeks) than in ours, possibly because lower water velocities in the subtidal permit mussels to be less strongly attached to the substratum. In contrast, Okamura (1986) found that M. edulis established in patches on tiles did not move from edge to central positions or vice versa. Paine (1974) —, Oo oO OA eh ee ey Ge 8) 2) 0) 0) Distance Moved (cm) Figure 2. Frequency distribution of distances moved by tagged mussels. Mussels were pooled over habitats (tidepools, emergent rock), positions (in patch, outside) and dates (August 1994, July and October 1995). Sample size, n = 68. found no distortion over 20 months of circles painted on undisturbed beds of Mytilus californianus, Conrad, 1837, although circles gradually became distorted if mussels were removed from an adjacent area. Mobility of mussels may depend on the availability of free space, the habitat type, and the species of mussel. Low mobility may be characteristic of M. californianus, the dominant mussel on the West Coast of North America. M. californianus crawls less rapidly (Harger, 1968), and has a stronger bys- sal attachment than other mytilids such as Mytilus edulis, M. trossulus, and M. galloprovincialis Lamarck, 1819 (Harger, 1970; Bell & Gosline, 1997). In our study, mussels inside patches, which are bound by the byssal threads of their neighbors as well as their own attachment to the substratum, moved less frequently than mussels outside of patches. Movement rates of mus- sels within patches were two to three times higher in July than in October 1995, whereas movement rates of indi- viduals outside of patches were similar in the two sea- sons. Byssal attachment of mussels varies seasonally (Price, 1980; Hunt & Scheibling, 2001b), and active movement by crawling may be easier in summer when byssal attachments are weaker (Hunt & Scheibling, 2001b) than in the fall. The distances moved by tagged mussels in our study were generally small (< 10 cm), resulting in changes in the position of a mussel within a patch or, less frequently, in emigration to a new patch (natural patches were usu- ally separated by 5-15 cm). Distances of movement did not vary seasonally, between habitats, or between indi- viduals inside or outside of patches. Movement within a patch may result in changes in growth rate or risk of predation, as these factors may vary with position in a patch (e.g., Okamura, 1986). Movement to a new patch may have similar consequences, as growth rate often de- The Veliger, Vol. 45, No. 4 pends on patch size (Okamura, 1986; Newell, 1990; Sva- ne & Ompi, 1993; Hunt & Scheibling, 2001a). Many of the tagged mussels disappeared during the study (e.g., up to 27% of individuals tagged in summer). Although there may have been some tag loss, we believe that most of these individuals were dislodged by waves. Wave dislodgment is an important cause of disturbance for mussels on rocky shores (e.g., Paine & Levin, 1981). Loss rates of mussels in this study were consistent with probabilities of wave dislodgment calculated for mussels at Cranberry Cove using measurements of attachment strength and wave forces (Hunt & Scheibling, 2001b). The disappearance rate of mussels in tidepools was great- er in October than July 1995, but did not differ between seasons on emergent rock. Dislodgment rates depend on both the wave forces imposed on individuals and on their attachment strength at a given time. Attachment strength and wave action vary seasonally, and these variations may counteract one another to dampen seasonality in the probability of wave dislodgment (Hunt & Scheibling, 2001b). At Cranberry Cove, wave forces are slightly higher on emergent rock than in tidepools (Hunt & Schei- bling, 2001b). However, between-habitat differences in probability of dislodgment of mussels were predicted to vary over time as a result of variations in attachment strength. Some of the mussels dislodged by waves likely attach in new locations. We found that both juvenile and adult mussels immigrate into mussel patches (Hunt & Scheibling, 2001a) and colonize cleared areas (Hunt & Scheibling, 1998b). In summary, we have documented movements of mus- sels in undisturbed patches on a wave-exposed shore. De- tailed monitoring of individual mussels, such as that done in this study, can reveal small movements that otherwise may be overlooked. Such movements potentially have consequences for rates of growth and risk of predation of mussels, since these rates vary with patch size and posi- tion within a patch. We also measured rates of loss of mussels that were consistent with our previous predic- tions of rates of wave dislodgment at Cranberry Cove (Hunt & Scheibling, 2001b). These results, together with our previous work on colonization (Hunt & Scheibling, 1998b) and patch dynamics (Hunt & Scheibling, 2001a) of mussels at this site, demonstrate that postlarval dis- persal can play an important role in the dynamics of mus- sel aggregations on rocky shores. LITERATURE CITED ANTHONY, K. R. N. & I. SvANe. 1995. Effects of substratum instability on locomotion and pedal laceration in Metridium senile (Anthozoa: Actiniaria). Marine Ecology Progress Se- ries 124:171—180. BELL, E. C. & J. M. GosLine. 1997. Strategies for life in flow: tenacity, morphometry, and probability of dislodgment of two Mytilus species. Marine Ecology Progress Series 159: 197-208. a ee H. L. Hunt & R. E. Scheibling, 2002 CarsEN, A. E., B. G. HATCHER, R. E. SCHEIBLING, A. W. HEN- NIGAR & L. H. TAyYLor. 1995. Effects of site and season on movement frequencies and displacement patterns of juvenile sea scallops Placopecten magellanicus under natural hydro- dynamic conditions in Nova Scotia, Canada. Marine Ecol- ogy Progress Series 128:225—238. De BLoK, J. W. & M. TANn-Maas. 1977. Function of byssus threads in young postlarval Mytilus. Nature 267:558. Denny, M. W. 1987. Lift as a mechanism of patch initiation in mussel beds. Journal of Experimental Marine Biology and Ecology 113:231—245. Do_mMer, P., M. KARLSSON & I. SVANE. 1994. A test of rheotactic behaviour of the blue mussel Mytilus edulis L. Phuket Ma- rine Biological Center Special Publication 13:177—184. HArGER, J. R. E. 1968. The role of behavioral traits in influencing the distribution of two species of sea mussel, Mytilus edulis and Mytilus californianus. The Veliger 11:45—49. Harcer, J. R. E. 1970. The effect of wave impact on some as- pects of the biology of sea mussels. The Veliger 12:401— 414. HetmutH, B. S. T. 1998. Intertidal mussel microclimates: pre- dicting the body temperature of a sessile invertebrate. Eco- logical Monographs 68:51—74. Hunt, H. L. & R. E. SCHEIBLING. 1998a. Effects of whelk (Nu- cella lapillus (L.)) predation on mussel (Mytilus trossulus (Gould), M. edulis (L.)) assemblages in tidepools and on emergent rock on a wave-exposed rocky shore in Nova Sco- tia, Canada. Journal of Experimental Marine Biology and Ecology 226:87-113. Hunt, H. L. & R. E. SCHEIBLING. 1998b. Spatial and temporal variability of patterns of colonization by mussels (Mytilus trossulus, M. edulis) on a wave-exposed rocky shore. Marine Ecology Progress Series 167:155—169. Hunt, H. L. & R. E. SCHEIBLING. 2001a. Patch dynamics of mus- sels on rocky shores: integrating process to understand pat- tern. Ecology 82:3213-3231. Page 277 Hunt, H. L. & R. E. SCHEIBLING. 2001b. Predicting wave dis- lodgment of mussels: variation in attachment strength with body size, habitat, and season. Marine Ecology Progress Se- ries 213: 157-164 MAAS GEESTERANUS, R. A. 1942. On the formation of banks by Mytilus edulis L. Archives Neerlandaises de Zoologie 6: 283-326. NEWELL, C. R. 1990. The effects of mussel (Mytilus edulis, Lin- naeus, 1758) position in seeded bottom patches on growth at subtidal lease sites in Maine. Journal of Shellfish Research 9:113-118. OKAMURA, B. 1986. Group living and the effects of spatial po- sition in aggregations of Mytilus edulis. Oecologia 69:341— 347. PAINE, R. T. 1974. Intertidal community structure: experimental studies on the relationship between a dominant competitor and its principal predator. Oecologia 15:93—120. PAINE, R. T. & S. A. LEVIN. 1981. Intertidal landscapes: Distur- bance and the dynamics of pattern. Ecological Monographs 51:145-178. Price, H. A. 1980. Seasonal variation in the strength of byssal attachment of the common mussel Mytilus edulis L. Journal of the Marine Biological Association of the United Kingdom 60:1035—1037. SEED, R. & T. H. SUCHANEK. 1992. Population and community ecology of Mytilus. Pp 87-169 in Gosling, E. (ed), The Mus- sel Mytilus: Ecology, Physiology, Genetics, and Culture. El- sevier: New York. SIGURDSSON, J. B., C. W. TITMAN & P. A. Davies. 1976. The dispersal of young post-larval bivalve molluscs by byssus threads. Nature 262:386—387. SVANE, I. & M. Ompr. 1993. Patch dynamics in beds of the blue mussel Mytilus edulis L.: effects of site, patch size, and po- sition within a patch. Ophelia 37:187—202. Wootton, J. T. 1993. Size-dependent competition: effects on the dynamics vs. the end point of mussel bed succession. Ecol- ogy 74:195—206. The Veliger 45(4):278—289 (October 1, 2002) THE VELIGER © CMS, Inc., 2002 Ankoravaratra, a New Genus of Land Snails Endemic to Northern Madagascar (Cyclophoroidea: Maizaniidae?) KENNETH C. EMBERTON Florida Museum of Natural History, Box 117800, Gainesville, Florida 32611, USA Abstract. Ankoravaratra, gen. nov. has a simple shell resembling that of the East-African subgenus Maizania (Mi- cromaizania) Verdcourt, 1964, from which it differs in having opercular coiling only half as tight. In reproductive morphology, Ankoravaratra, gen. nov. differs substantially from all anatomically known cyclophoroids, including mai- zaniids, so its familial placement remains uncertain. The genus contains five species, of which four are new and one is transferred. INTRODUCTION This paper is one in a series reporting taxonomic results from the author’s 1992-1996 survey and inventory of Madagascar’s land mollusks (references in Emberton, 2002). MATERIALS AnD METHODS Materials were collected in 1995 using methods of Em- berton et al. (1996). Identification and comparisons were made using Bequaert & Clench (1936), Wenz (1938-— 1944), Tielecke (1940), Morton (1952), Zilch (1959— 1960), Solem (1959), Verdcourt (1963, 1964), Thompson (1969), Girardi (1978), Bruggen (1982, 1985, 1986, 1990), Fischer-Piette et al. (1993), and Emberton & Pear- ce (1999), and using the collections of the Florida Mu- seum of Natural History. Templeton’s (1989) cohesion concept was applied in delimiting species. Measurements were made using an ocular micrometer on a Wild M3C dissecting microscope. Dissections were on black wax under 70% ethanol, following procedures of Emberton & Pearce (1999:figures 32, 49, 50). Photographs were taken at standard magnifications (10 and 25x). LOCALITIES Of the 1126 stations collected throughout Madagascar in 1992-1996, only the following 11. stations—all north- ern—yielded Ankoravaratra, gen. nov. 191-195. Montagne d’ Ambre National Park, rainforest. 191. 12°35'S, 49°09’E, 1260 m, 11 July 1995. 192-195. 12 July 1995. 192. 12°35'S, 49°08’E, 1235 m. 193-194. 12934'S, "49509'E 4 193.) 11305: ms 1945 1280) my 195: 12°31’S, 49°10’E, 1050 m. 201-213. Analamera Reserve. 201, 203. 12°44’S, 49°30'E. 201. 315 m, dry deciduous forest, 15 July 1995. 203-213. 16 July 1995. 203. 285 m, bamboo-dry decid- uous thicket. 210, 213. 12°44'S, 49°29’E, dry deciduous floodplain forest. 210. 35 m. 213. 30 m. 256. South of Vohimar, 13°35’S, 49°59’E, 90 m, viny rainforest, 2 September 1995. 405, 407. Cap d’Ambre, Ambongoabo, 12°15’S, 49°15'E. 405. 320 m, baobab-deciduous forest, 25 August 1995. 407. 290 m, dry deciduous forest, 26 August 1995. SYSTEMATICS Higher classification follows Ponder & Lindberg (1997; above superfamily) and Vaught (1989; superfamily and family). Latitudes and longitudes are given in degrees and minutes. To aid future workers, alcohol-preserved para- types are listed separately. Types are placed in the Florida Museum of Natural History, University of Florida, Gainesville (UF); the Australian Museum, Sydney (AMS); the Academy of Natural Sciences of Philadelphia (ANSP); and the Muséum National d’ Histoire Naturelle, Paris (MNHN, which does not assign catalogue numbers to types). Class GASTROPODA Clade CAENOGASTROPODA Clade ARCHITAENIOGLOSSA Superfamily CYCLOPHOROIDEA Family MAIZANIIDAE? Ankoravaratra Emberton, gen. nov. (Figures 1—33) Type species: Ankoravaratra ambrensis, sp. nov. Other species: A. ambalaniranae, sp. nov.; A. ana- lamerae, sp. nov.; A. capdambrae, sp. nov.; A. imani K. C. Emberton, 2002 (Fischer-Piette, Blanc, Blanc & Salvat, 1993), comb. nov. Diagnosis: Ankoravaratra, gen. nov. has a simple shell and thin, horny, single-layered, nearly circular, spiral operculum resembling those of East-African subgenus Maizania (Micromaizania) Verdcourt, 1964, from which it differs in having opercular coiling only half as tight (opercular whorls equal to number of shell whorls versus double the number of shell whorls). Anatomically, Ankoravaratra resembles Owengriffith- sius (Emberton, 2002) in its bulbous-tipped penis in which seminal tube is enclosed (no seminal groove), api- cally looped, and subapically opening, and which bears a thick, semi-circular, flaplike gland; but Ankoravaratra has an extremely different shell morphology and has sin- gle-saccate (versus double-saccate) bursa copulatrix. In penial morphology, Ankoravaratra differs substan- tially from all other (of the relatively few) anatomically known cyclophoroid genera, including maizaniids Mai- zania Bourguignant, 1889; Maizaniella Bequaert & Clench, 1936; and Neomaizania Bruggen, 1985. Female reproductive system of Ankoravaratra, gen. nov. is drastically different from that of type species of Maizania in its unstalked (versus long-stalked) bursa co- pulatrix, absence (versus presence) of accessory sac on seminal receptacle, and relatively short and S-shaped (versus long and very convoluted) seminal receptacle. Conchologically, Theobaldius G. Nevill, 1878, has similar operculum, shell shape and size, and smoothish sculpture to Ankoravaratra, gen. nov., but its peristome is more broadly reflected and is either doubled, or has a distinct anal notch, or both. Other cyclophorid genera with similar operculum, such as Cyclophorus Montfort, 1810, have much larger, more robust shells with much thicker, more reflected peri- stomes. Ptychopoma Mollendorf, 1885, has a somewhat similar shell, but its operculum is thick and calcified and its sculpture is not smoothish. Other cyclophorid general that can be similar in shell shape and size, such as Cyclotus Swainson, 1840, and Poteria Gray, 1850, have extremely different opercula. Description: Shell depressed-helicoid, diameter 6.4—9.6 mm, height/diameter 0.5—0.8, whorls 4.2—5.7, umbilicus/ diameter 0.23—0.33. Spire low conic, sides of apex gen- erally slightly concave. Body-whorl periphery rounded; suture deeply impressed, simple; whorl shoulders round- ed. Aperture round; pre-apertural downward deflection slight, approximately 0.1 whorl. Apertural lip unreflected at upper suture, grading to partially and very narrowly reflected at umbilicus. Embryonic whorls 1.7—2.0; first 1.5 whorls 0.96—1.15 mm in diameter. Embryonic sculp- ture smooth. Body-whorl sculpture either smooth, with faint, irregular, axial growth lines; or with low, dense rib- lets. Color generally light, often with whitish flecks, Page 279 sometimes with single, reddish brown, peripheral color band. Operculum fairly thin, horny, orange-yellow, broadly ovate, nearly circular, with parietal edge straight and rolled inward. Nucleus slightly eccentric toward baso-col- umellar edge. Whorls gradually and evenly increasing, approximately equal in number to shell whorls. On both external and internal surfaces, whorls bearing a low, broad, spiral ridge near suture. External surface smooth, glossy; internal surface rougher, with substructure resem- bling spirally radiating cross-laminated layers of parallel fibers. Foot relatively short and broad, undivided. Snout short, divided into two lobes by narrow, central cleft. Testis large, nearly completely displacing apical digestive gland. Penis with completely enclosed seminal tube, without seminal groove. Penis cylindrical, apically swelling then tapering and coiling back on, and adhering to, itself in a 230—260° loose spiral. Penial pore thus subapical behind bulbous, false tip, and opening to side, but angled some- what forward. Within penial pore, through translucent wall of true tip of the penis, a terminal, invaginable, in- tromittant portion of penis is visible. Left side of penis bearing a thick, semi-circular, flaplike gland that rolls par- tially around penial shaft. Ovary relatively small, lying along inside curve of apical digestive gland, consisting of tightly packed, bulbous acini. Oviduct (= “tube of FPSC” of Emberton & Pearce [1999]) with a sharp, V- shaped bend before running alongside, then tapering into, seminal receptacle. Seminal receptacle (= ‘‘albumen gland”’ of Thompson [1969] = “glandular base of FPSC”’ of Emberton & Pearce [1999]) narrow and V- to U- shaped shortly after its indistinct junction with oviduct, then swelling greatly and forming an S-shaped curve that straightens distally, before its junction with bursa copu- latrix. Bursa copulatrix (= “seminal receptacle” of Thompson [1969] = “gland of FPSC”’ of Emberton & Pearce [1999]) a single, ductless sac. Etymology: Malagasy ‘“‘snail’’ (ankora) of the ‘“‘north”’ (avaratra), for the strictly northern distribution of this ge- nus in Madagascar. Gender: Feminine. Key to Species of Ankoravaratra: la. Diameter of first 1.5 whorls less than 1.00 mm __. 2 1b. Diameter of first 1.5 whorls greater than 1.00 mm __ 3 2a. Diameter of first 1.5 whorls about 0.89 mm; in- habiting dry-deciduous forest on limestone karst Se ion oD Aart eee Ree SSD on RS, IL Sek imant 2b. Diameter of first 1.5 whorls 0.96—0.98; inhabiting rainforest on non-calcareous base rock ——— PI Sarees AG Sess fs Ramicee ce, Steet ie ON ETTaE eee ambalaniranae 3a. Body-whorl sculpted with low, dense riblets; Page 280 The Veliger, Vol. 45, No. 4 body-whorl periphery faintly angulate; inhabiting OFAN ON C6) REA tetas eee ar at I ole ambrensis 3b. Body whorl smooth, with only faint, irregular growth lines; body-whorl periphery round; inhab- iting dry-deciduous forest 2 4 4a. Diameter of first 1.5 whorls 1.10—1.15 mm; em- bryonic whorls 1.7—1.8; umbilicus broader, 0.29— 0.32 shell diameter; shell generally with color ena Eto as 2 UPA eet nee analamerae 4b. Diameter of first 1.5 whorls 1.03—1.06 mm; em- bryonic whorls 1.9—2.0; umbilicus narrower, 0.23-0.27 shell diameter; shell generally without Color! band ie 2s eee aes capdambrae Species Descriptions Ankoravaratra ambalaniranae Emberton, sp. nov. (Figures 25—29) Diagnosis: Unique within genus for its combination of small initial-whorl size (diameter of first 1.5 whorls 0.96— 0.98 mm) and rainforest habitat. Holotype: Station 256 (UF 285436, | ad). Illustrated dry paratypes: Station 256 (UF 285437, 3 ad, 1 juv). Other dry paratypes: Station 256 (AMS C. 204777, 1 ad; ANSP 407915, 1 ad; MNHN, | ad; UF 285477, 4 ad, 7 juv). Type locality: Madagascar, South of Vohimar, 13°35’S, 49°59’E, 90 m, viny rainforest. Description of holotype shell (Figure 25): Female. Di- ameter 9.6 mm, height 6.5 mm, whorls 5.3, umbilicus 2.8 mm. Spire low conic, sides of apex slightly concave. Body-whorl periphery rounded; suture deeply impressed, simple; whorl shoulders rounded. Aperture round; height 3.6 mm, width 3.6 mm; downward deflection slight, 0.1 whorl. Apertural lip reflection grading from zero degrees at upper suture to about 60 degrees at umbilicus, narrow. Embryonic whorls 1.9; first 1.5 whorls 0.98 mm in di- ameter. Embryonic sculpture smooth. Body-whorl sculp- ture smooth, with faint, irregular, axial growth lines. Col- or light beige with white flecks. No color band. Shell variation: See Table | and Figures 26-29. Operculum (Figure 29): As for the genus. Etymology: For Mount Ambalanirana, north of Sambava. Ankoravaratra ambrensis Emberton, sp. nov. (Figures 1-19) Diagnosis: Unique within the genus for its body-whorl sculpture of low, dense riblets and its faintly angulate body-whorl periphery. Holotype: Station 191 (UF 285442, 1 ad). Illustrated dry paratypes: Station 191 (UF 285443, 4 ad, 1 juv, 2 operc). Illustrated alcohol paratypes: Station 191 (UF 285571, 6 ad [dissected]). Other dry paratypes: Stations 191 (AMS C. 203496, 3 ad, 2 operc; ANSP 407916, 3 ad, 1 operc; MNHN, 3 ad, 1 operc; UF 285567, 28 ad, 63 juv); 192 (UF 285569, 3 ad, 3 juv); 193 (UF 285568, 5 ad, 8 juv); 194 (UF 285570, 2 ad); 195 (UF 285566, 1 ad). Other alcohol paratypes: Stations 191 (UF 285572, 11 ad, 2 juv); 192 (UF 285573, 1 ad). Type locality: Madagascar, Montagne d’ Ambre National Park, 12°35’S, 49°09’E, 1260 m, rainforest. Description of holotype shell (Figure 1): Female. Di- ameter 8.7 mm, height 5.7 mm, whorls 4.7, umbilicus 2.3 mm. Spire low conic, sides of apex slightly concave. Body-whorl periphery rounded, with just faint trace of angulation; suture deeply impressed, simple; whorl shoul- ders rounded. Aperture round; height 3.3 mm, width 3.4 mm; downward deflection slight, 0.1 whorl. Apertural lip reflection grading from zero degrees at upper suture to about 60 degrees at umbilicus, narrow. Embryonic whorls 1.8; first 1.5 whorls 1.09 mm in diameter. Embryonic sculpture smooth. Body-whorl sculpture consisting of low, dense riblets, continuing into umbilicus. General color orangish beige with whitish flecks. Color band present, subperipheral, reddish brown. Shell variation: See Table 1 and Figures 2-5. Operculum (Figures 6, 7): As for the genus. Anatomy (Figures 8-19, ethanol-fixed and -pre- served): As for the genus. Etymology: For Montagne d’Ambre (Amber Mountain) National Park. Ankoravaratra analamerae Emberton, sp. nov. (Figures 20—24) Diagnosis: Unique within the genus for its large initial whorl size (diameter of first 1.5 whorls 1.10—1.15 mm). Holotype: Station 213 (UF 285438, 1 ad). Illustrated dry paratypes: Stations 201 (UF 285440, 2 ad); 203 (UF 285441, 1 ad); 213 (UF 285439, 1 ad). Other dry paratypes: Stations 201 (AMS C. 203497, 1 ad; ANSP 407917, 1 ad; MNHN, 1 ad; UF 285466, 7 ad, 1 juv); 203 (UF 285468, 6 ad, 4 juv); 210 (UF 285469, 1 ad, 1 juv); 213 (UF 285467, 8 ad, 5 juv). Type locality: Madagascar, Analamera Reserve, 12°44'S, 49°29'E, 30 m, dry deciduous floodplain forest. K. C. Emberton, 2002 Figures 1-5. Shells of Ankoravaratra ambrensis Emberton, gen. & sp. nov. Figure 1. Holotype in three views (UF 285442). Figures 2-5. Paratypes from type locality, in one view (UF 285443). Figures 2, 3. Males, specimens #1, 2. Figures 4, 5. Females, specimens #3, 4. Scale bar = 1 mm. Description of holotype shell (Figure 20): Female. Di- ameter 9.1 mm, height 6.3 mm, whorls 5.2, umbilicus 2.6 mm. Spire low conic, sides of apex slightly concave. Body-whorl periphery rounded; suture deeply impressed, simple; whorl shoulders rounded. Aperture upright broad- ly oval; height 3.5 mm, width 3.4 mm; downward de- flection slight, 0.1 whorl. Apertural lip reflection un- known, but reflected at umbilicus. Embryonic whorls 1.8; Page 282 The Veliger, Vol. 45, No. 4 Figures 6, 7. Opercula of Ankoravaratra ambrensis Emberton, gen. & sp. noy., in exterior (left) and interior (right) views (ex UF 285571). Figure 6. Type-locality male, specimen #3. Figure 7. Specimen #6. Scale bar = 1 mm. Kee Emberton) 2002 Page 283 Figures 8-13. Bodies (shells removed) of Ankoravaratra ambrensis Emberton, gen. & sp. nov., from the type locality (UF 285571). Figures 8—10.Males, specimens #1—3, respectively. Figures 11-13. Females, specimens #4—6, respectively. Scale bar = 1 mm. Page 284 The Veliger, Vol. 45, No. 4 Figures 14-19. Reproductive organs of Ankoravaratra ambrensis Emberton, gen. & sp. novy., from the type locality (UF 285571). Figures 14-16. Penes in dorsal and ventral views (upper and lower, respectively) of males, specimens #1-—3, respectively. Figures 17— 19. Oviduct-plus-seminal receptacle-plus-bursa copulatrix of females, specimens #4—6, respectively. Scale bar = 1 mm. K. C. Emberton, 2002 Page 285 Table | Shell variation. Abbreviations: # specimen number, CBand color bands, D1.5W diameter of first 1.5 whorls, Dm shell diameter, EmW embryonic whorl count, fem female, Ht/D shell height divided by shell diameter, Um/D umbilicus diameter divided by shell diameter, W/InD shell whorl count divided by natural logarithm of shell diameter (= index of coiling tightness), Whrl shell whorl count. Species Catalog # # Sex Dm Ht/D Whrl W/InD Um/D D1.S5W EmW_- CBand ambalaniranae UF 285436 - fem 9.6 0.7 Sc) 2.35 0.29 0.98 1.9 no ambalaniranae UF 285437 1 male 7.0 0.7 4.7 2.41 0.27 0.96 1.9 trace ambalaniranae UF 285437 2 male VP 0.7 4.8 2.44 0.31 0.98 t&) yes ambalaniranae UF 285437 38 fem 9.6 0.7 Sl 2.26 0.30 0.98 1.8 no ambrensis UF 285442 — fem 8.7 0.7 4.7 2.18 0.26 1.09 1.8 yes ambrensis UF 285443 | fem 8.7 0.6 Sal) 2.64 0.31 1.06 1.9 yes ambrensis UF 285443 2 fem 8.6 0.6 5.6 2.60 0.33 1.03 1E9 no ambrensis UF 285443 3 male Hol 0.7 4.5 2.30 0.28 1.08 1.8 yes ambrensis UF 285443 4 male 6.7 0.7 4.4 2.33 0.29 1.06 19. yes ambrensis UF 285571 1 male VS 0.6 4.3 2.14 - - 1H no ambrensis UF 285571 2 male VP 0.7 4.5 2.28 _ - 1.8 no ambrensis UF 285571 3 male 2 0.6 4.2 2.13 - - 1.7 no ambrensis UF 285571 4 fem 8.3 0.6 4.7 2.23 - - Te no ambrensis UF 285571 5 fem 8.9 0.6 4.7 2.15 - - 1.8 yes ambrensis UF 285571 6 fem OD 0.7 4.8 2.16 - ~ sy yes analamerae UF 285438 - fem 9.1 0.7 SS DSS 0.29 1.10 1.8 yes analamerae UF 285440 1 male Vol 0.5 4.3 Dr aeD, 0.32 13} — yes analamerae UF 285440 2 fem 9.3 0.5 4.6 2.06 0.31 1S - yes analamerae UF 285441 = male 6.8 0.6 4.2 2.19 0.31 1.15 = yes analamerae UF 285439 - fem 8.5 0.6 4.7 2.20 0.29 1.10 Noy trace capdambrae UF 285444 — fem 9.1 0.8 Sl 2.31 0.23 1.06 1.9 no capdambrae UF 285445 - male 6.7 0.7 4.6 2.43 0.27 1.03 2.0 no capdambrae UF 285446 1 fem Te 0.8 4.9 2.40 0.27 1.04 1.9 no capdambrae UF 285446 2 male 6.4 0.8 4.7 DES 0.25 1.04 1.0 no first 1.5 whorls 1.10 mm in diameter. Embryonic sculp- ture smooth. Body-whorl sculpture smooth, with faint, irregular, axial growth lines. General color orange-beige with purplish cast. Color band present, purplish brown, edged with white above and below. Shell variation: See Table 1 and Figures 21—24. Etymology: For Analamera Reserve. Ankoravaratra capdambrae Emberton, sp. nov. (Figures 30-33) Diagnosis: Unique within the genus for its combination of large initial-whorl size (diameter of first 1.5 whorls 1.03—1.06 mm) and dry-deciduous-forest habitat. Holotype: Station 407 (UF 285444, 1 ad). Illustrated dry paratypes: Stations 405 (UF 285445, 1 ad); 407 (UF 285446, 2 ad). Other dry paratypes: Stations 405 (UF 285472, 3 ad, 5 juv); 407 (AMS C.203498, 1 ad; ANSP 407918, | juv; MNBN, | ad; UF 285473, 1 ad, 4 juv). Type locality: Madagascar, Cap d’ Ambre, Ambongoabo, 12°15'S, 49°15’E, 290 m, dry deciduous forest. Description of holotype shell (Figure 30): Female. Di- ameter 9.1 mm, height 7.1 mm, whorls 5.1, umbilicus 2.1 mm. Spire conic, slightly domed. Body-whorl periphery rounded; suture deeply impressed, simple; whorl shoul- ders rounded. Aperture upright broadly oval; height 3.4 mm, width 3.3 mm; downward deflection great, 0.2 whorl. Apertural lip reflection grading from zero degrees at upper suture to about 60 degrees at umbilicus, extreme- ly narrow. Embryonic whorls 1.9; first 1.5 whorls 1.06 mm in diameter. Embryonic sculpture smooth. Body- whorl sculpture smooth, with faint, irregular, axial growth lines. General color brownish yellow, apex and upper whorls light orange. No color band. Shell variation: See Table | and Figures 31-33. Operculum (Figure 33): As for the genus. Etymology: For Cap d’Ambre (Tanjona Bobaomby). Ankoravaratra imani (Fischer-Piette, Blanc, Blanc & Salvat, 1993), comb. nov. Chondrocyclus (?) imani n. sp., Fischer-Piette et al., 1993: 17-19, figure 11. Diagnosis: Unique within the genus for its very small initial whorl (diameter of first 1.5 whorls about 0.89 mm). Page 286 The Veliger, Vol. 45, No. 4 Figures 20-24. Shells of Ankoravaratra analamerae Emberton, gen. & sp. nov. Figure 20. Holotype in three views (UF 285438). Figures 21—24. Paratypes in one view. Figures 21, 22. Males (UF 285440, specimen #1; and UF 285441, respectively). Figures 23, 24. Females (UF 285440, specimen #2; and UF 285439, respectively). Scale bar = 1 mm. K. C. Emberton, 2002 Page 287 Figures 25-29. Shells of Ankoravaratra ambalaniranae Emberton, gen. & sp. nov. Figure 25. Holotype in three views (UF 285436). Figures 26-29. Paratypes from the type locality, in one view (UF 285437). Figures 26, 27. Males, specimens #1 and 2. respectively. Figure 28. Female, specimen #3. Figure 29. Juvenile with its operculum in interior view, specimen #4. Scale bar = 1 mm. Description of holotype shell: Based on Fischer-Piette et al.’s (1993) figure 11. Diameter 7.1 mm, height 4.0 mm, whorls 4.7, umbilicus 2.4 mm. Spire low domed- conic, sides of apex slightly concave. Body-whorl pe- riphery rounded; suture deeply impressed, simple: whorl shoulders rounded, apparently. Aperture nearly round: height 2.4 mm, width 2.5 mm; peristome reflection slight, narrow, greatest at columella. First 1.5 whorls approxi- The Veliger, Vol. 45, No. 4 Page 288 Shells of Ankoravaratra capdambrae Emberton, gen. & sp. nov. Figure 30. Holotype in three views (UF 285444). respectively, from type locality (UF > Figures 30-33. Figures 31-33. Paratypes in one view. Figures 31, 32. Male and female, specimens #2 and | 285446). Figure 33. Male with its operculum in exterior view (UF 285445). Scale bar = 1 mm. K. C. Emberton, 2002 mately 0.89 mm in diameter. Embryonic sculpture smooth. Body-whorl sculpture of “‘very irregular growth lines, often located on the lower part of the whorl, with- out reaching the suture. Color “‘opaque, whitish, with the summit brownish-rosish.”” No color band. Distribution: Ankarana Reserve, northern Madagascar. Acknowledgments. Collection, sorting, housing, identification, and computer cataloguing funded by the U.S. National Science Foundation (DEB 9201060/9596032): description funded by Owen Griffiths. Permits were issued by the Madagascar govern- ment agencies DEF and ANGAP. Ranomafana National Park Project gave logistic support. Very many people collected or oth- erwise assisted, but particular thanks go to Dr. Tim Pearce, Jean Rakotoarison, the late Max Felix Rakotomalala, and Josephine Emberton. Dr. Fred Thompson and two anonymous reviewers gave useful comments on drafts of the manuscript. EEE RAGORE CUED BEQUAERT. J. & W. J. CLENCH. 1936. Studies of African land and freshwater mollusks. VII. New species of land operculates, with descriptions of a new genus and two new subgenera. Revue de Zoologie et de Botanique Africaines 29:97—104, pls. I and Il. BRUGGEN, A. C. VAN. 1982. A revision of the African operculate land snail genus Maizaniella (Gastropoda Prosobranchia: Maizaniidae), with the description of six new taxa. Proceed- ings of the Koninklijke Nederlandse Akademie van Weten- schappen, Series C 85:179-204. BRUGGEN, A. C. VAN. 1985. Neomaizania coryli, a new genus and species of Maizaniidae (Mollusca Gastropoda Proso- branchia) from Malawi, South Central Africa. Proceedings of the Koninklijke Nederlandse Akademie van Wetenschap- pen, Series C 88:395—403. BRUGGEN, A. C. VAN. 1986. Further notes of Afrotropical pros- obranch land molluscs (Gastropoda Prosobranchia: Maiza- niidae). Proceedings of the Koninklijke Nederlandse Aka- demie van Wetenschappen, Series C 89:357-378. BRUGGEN, A. C. VAN. 1990. Notes on the genus Maizaniella (Gastropoda, Prosobranchia: Maizaniidae), with the descrip- tion of a new species from West Africa. Basteria 54:187— 195. EMBERTON, K. C. 2002. Owengriffithsius new genus of cyclo- phorid land snails endemic to northern Madagascar. The Ve- liger 45(3):203-217. Page 289 EMBERTON, K. C. & T. A. PEARCE. 1999. Land caenogastropods from Mounts Mahermana, Ilapiry, and Vasiha, southeastern Madagascar, with conservation statuses of 17 species of Boucardicus. The Veliger 42:338—372. EMBERTON, K. C., T; A. PEARCE & R. RANDALANA. 1996. Quan- titatively sampling land-snail species richness in Madagas- can rainforests. Malacologia 38:203—212. FISCHER-PIETTE, E., C. P- BLANC, EF BLANC & FE SaLtvart. 1993. Gastéropodes terrestres prosobranches. Faune de Madagas- car 80:1—281. GiRARDI, E.-L. 1978. The Samoan land snail genus Ostodes (Mollusca: Prosobranchia: Poteriidae). The Veliger 20:191— 250. Morton, J. E. 1952. A preliminary study of the land operculate Murdochia pallidum (Cyclophoridae, Mesogastropoda). Transactions of the Royal Society of New Zealand 80:69— 79, pls. 25-26. PONDER, W. F & D. R. LINDBERG. 1997. Towards a phylogeny of gastropod molluscs: an analysis using morphological characters. Zoological Journal of the Linnean Society 119: 83-265. SoLeM, A. 1959. Systematics and Zoogeography of the land and fresh-water Mollusca of the New Hebrides. Fieldiana:Zool- ogy 43:1-359, pls. 1-34. TEMPLETON, A. R. 1989. The meaning of species and specifica- tion: a genetic perspective Pp. 3—27 in D. Otte & J. A. En- dler (eds.), Specification and Its Consequences. Sinauer As- sociates: Sunderland, Massachusetts. THompson, EF G. 1969. Some Mexican and Central American land snails of the family Cyclophoridae. Zoologica: New York Zoological Society 54:35—77, pls. I-VI. TIELECKE, H. 1940. Anatomie, Phylogenie und Tiergeographie der Cyclophoriden (aus der Mollusken-Abteilung des Zool- ogischen Museums der Universitaet Berlin). Archiv fiir Sys- tematische Zoologie, Neue Folge 9:317—371. VAUGHT, K. C. 1989. A Classification of the Living Mollusca. American Malacologists Inc.: Melbourne, Florida. VERDCOURT, B. 1963. A new species of Maizania from northern Kenya. Archiv fiir Molluskenkunde 92:15-17. VERDCOURT, B. 1964. The genus Maizania Bgt. (Gastropoda, Maizaniidae) in eastern Africa. The Journal of the East Af- rica Natural History Society and Coryndon Museum 24:1— 22 WENZ, W. 1938-1944. Gastropoda, Teil 1: Allgemeiner Teil und Prosobranchia. Band 6, Pp. 1—1639 in O. H. Schindewolf (ed.), Handbuch der Paléozoologie. Gebriider Borntrager: Berlin. The Veliger 45(4):290—298 (October 1, 2002) THE VELIGRR © CMS, Inc., 2002 Dichotomous Life History Patterns for the Nudibranch Dendronotus frondosus (Ascanius, 1774) in the Gulf of Maine CHAD G. SISSON Department of Zoology, University of New Hampshire, Durham, New Hampshire 03824, USA Abstract. The nudibranch Dendronotus frondosus has a wide distribution and different morphological, ecological, and life history traits within its range. In the Gulf of Maine, populations can be found with either lecithotrophic or planktotrophic veliger larvae. Adults with these two types of larvae have overlapping habitat distributions, but the veligers differ in size, basic developmental characteristics, and composition of gelatinous clutches. Seasonal patterns of size distribution of adults suggest a sub-annual life cycle for those with planktotrophic larvae and an annual life cycle for those with lecithotrophic larvae. A feeding experiment with two types of hydroid prey resulted in lower growth rates for one dietary treatment, although this did not result in a shift in larval type. Mating recognition trials suggest a behavioral reproductive isolating mechanism between some populations. These results show little evidence for poecil- ogony and are motive for a taxonomic review of a D. frondosus complex in the Gulf of Maine. INTRODUCTION Poecilogony is broadly defined as multiple larval devel- opment modes within members of a single species (Hoag- land & Robertson, 1988; Levin & Bridges, 1995). Ex- amples of this phenomenon have frequently been shown to be sibling species complexes (Hoagland & Robertson, 1988), and proven examples of poecilogonous marine in- vertebrates include a limited number of species of spionid polychaetes and opisthobranch gastropods (Levin, 1984; Bouchet, 1989; Krug, 1998). When studying differences in reproductive traits within these groups, the possibility for poecilogony must be examined. Dendronotus frondosus (Ascanius, 1774) is a cosmo- politan nudibranch in northern temperate coastal waters and one of the most common opisthobranchs in the Gulf of Maine; however, descriptions of the habitat ecology, reproductive ecology, and general morphology of this species vary significantly (Alder & Hancock, 1845-1855; MacFarland, 1966; Robilliard, 1970). For example, a va- riety of hydroid diets have been associated with D. fron- dosus (McDonald & Nybakken, 1999). With this range of diets follow drastic differences in pigmentation pat- terns (Robilliard, 1975) and qualitative variation in ceras and foot morphology (personal observation). In addition, life history information varies considerably for reported reproductive season and general developmental charac- teristics (Swennen, 1961; Clark, 1975; Thompson & Brown, 1984). Because of these varying attributes, over 17 different taxonomic designations have confused the status of D. frondosus, as this species continues to be redefined in the literature (Robilliard, 1970; Thollesson, 1998). Reports of this species have been accumulated from Norway, Greenland, the western and eastern North American coasts, and the northern Asiatic coast (Robil- liard, 1970), largely because this species epithet continues to be a general designation for the genus Dendronotus. Dendronotus frondosus feeds on a variety of athecate (e.g., Tubularia spp.) and thecate (e.g., Obelia spp.) hy- droids (Miller, 1961; Swennen, 1961; Todd, 1981), and differences in diet often are coupled with drastic differ- ences in physical habitats and seasonal population fluc- tuations. In the Gulf of Maine, D. frondosus habitats range from southern coastal areas associated with subtidal hydroid communities (Clark, 1975; Lambert, 1991) to the Bay of Fundy and northern Nova Scotia (Meyer, 1971; Bleakney, 1996). Throughout the region these slugs are commonly found in subtidal thecate hydroid communities and fouling communities with athecate hydroid colonies (Meyer, 1971; Clark, 1975; Lambert, 1991). In northern regions of the Gulf of Maine, D. frondosus regularly oc- curs in intertidal habitats associated with the thecate hy- droid Sertularia pumila, a common rockweed epiphyte (Meyer, 1971; Gionet & Aiken, 1992; Bleakney, 1996). In the North Atlantic, in addition to variability of hab- itats, D. frondosus shows a range of reproductive patterns. Reports of seasonal spawning vary from strictly annual (Clark, 1975) to nearly year-round (Swennen, 1961). Lar- val feeding type may also differ; both lecithotrophic (Thompson & Brown, 1984) and planktotrophic larvae (Clark, 1975) have been described for this species on op- posite sides of the Atlantic. Hoagland & Robertson (1988) noted that these allopatric differences in life his- tory data warrant further examination for the possibility of poecilogony. This paper outlines subtidal and intertidal habitats of D. frondosus in the Gulf of Maine and describes variation in the larval development and feeding type of this nudi- C. G. Sisson, 2002 Page 291 Figure 1. Map of study sites on the Maine and New Hampshire coastline. Southern subtidal sites include York and Isles of Shoals. Northern subtidal sites include Winter Harbor, Eastport, and Pembroke. Northern intertidal sites include Pembroke and West Quoddy Head. branch associated with differences in habitat ecology. These observations were motive for a simple reciprocal feeding experiment to evaluate the effects of two major diets on the type of larvae produced. A mating recogni- tion experiment provided data on the potential for repro- ductive isolation of the most disparate groups of D. fron- dosus, although a formal taxonomic review is not includ- ed in this paper. MATERIALS AND METHODS Collection and Life History Observations I collected Dendronotus frondosus individuals from in- tertidal and subtidal (S—10 m deep) sites in the Gulf of Maine between March 1997 and August 1998 (Figure 1). Southern subtidal sites were at Cape Neddick in York, Maine (43°00'N, 70°36’W), and at the Isles of Shoals, New Hampshire (44°21'N, 68°03’W). Northern subtidal sites were at Winter Harbor (44°53’'N, 67°09’W), Eastport (44°54'N, 66°59’W) and Pembroke (44°53’N, 67°09’W), Maine. Northern intertidal collection sites included Pem- broke and West Quoddy Head (44°49’N, 66°57'’W), Maine. I monitored these sites three to six times/year to establish seasonal patterns in spawning behavior. Adult D. frondosus were maintained in a 10°C temperature-con- trolled room at the University of New Hampshire (UNH) Durham campus and fed hydroids (Obelia spp. and Ser- tularia spp.) found as epiphytes on the rockweed Asco- phyllum nodosum. Lengths of nudibranchs were measured with an ocular micrometer and a dissecting microscope while the animals were actively crawling on a flat sub- merged surface. I isolated individual nudibranchs for 1—2 days at 10°C in order to collect spawn masses when they were depos- ited. All larval measurements were made with an ocular micrometer (+10 wm) and a compound microscope. Zy- gote diameters were measured by haphazardly selecting 10 zygotes in the center region of different spawn masses. The embryos were then placed in 200 mL plastic-covered containers with natural seawater (32-35 ppt) and gently aerated. I changed the water and culture container two times per week and monitored the development of the embryos until they began to hatch from the capsules and gel matrix of the mass. The number of days until hatching for each spawn mass (+1 day) was recorded. I then mea- sured the maximum shell length from the aperture just above the velum of three to seven larvae from four spawn masses for each larval type. Immediately after hatching, several larvae were presented with hydroid material (Obelia and Sertularia spp.) and observed for signs of Page 292 induction of metamorphosis such as resorbtion of the ve- lum and the loss of shell and operculum (Todd, 1981). Planktotrophic and lecithotrophic larvae from four differ- ent spawn masses for each type were placed into glass stacking dishes in seawater at approximately one to two veligers/mL. The larvae were maintained at 10°C and fed small amounts of the cultured microalgae, /sochrysis gal- bana and Rhodomonas salina. After 1 week of culture, the larvae were examined with a compound light micro- scope for the presence of algal material in their gut. Reciprocal Feeding Experiment Two reciprocal feeding experiments helped me deter- mine the quality of two hydroid diets and the plasticity of the larval types produced by adults fed these diets. I haphazardly collected 60 juvenile D. frondosus (12.9— 34.5 mm) from northern intertidal sites in October 1997, and placed them in covered plastic containers (18.4 x 16.5 X 11.1 cm) with two opposite mesh windows in flow-through seawater tables at the UNH Coastal Marine Laboratory in Newcastle, New Hampshire. The two die- tary treatments were either Obelia or Sertularia spp. found as epiphytic colonies on Ascophyllum nodosum on a nearby pier, fed to the nudibranchs one to two times per week, amounting to an ad libitum regime. After 3 months, I measured the remaining 51 individuals (22 fed on Obelia spp. and 29 fed on Sertularia spp.) and paired them for mating and production of spawn masses. Eleven pairs of nudibranchs from the Obelia treatment and 13 pairs fed Sertularia spp. were observed as they spawned for 2 months. A similar experiment used D. frondosus from southern subtidal sites with the same feeding and maintenance schedules. Starting lengths ranged from 3.3—16.7 mm for the 72 juveniles collected between March and April 1998. The final measurements were collected after only 4 weeks of growth when mortality reduced the number of survi- vors to 36 slugs (24 fed Obelia spp., 12 fed Sertularia spp.). Additional mortality reduced the number of pairs of nudibranchs to 10 pairs for the Obelia treatment and five pairs for the Sertularia treatment which were ob- served as they spawned for an additional 2 weeks. The total number of spawn masses was then recorded and the larvae were allowed to develop until I could dis- tinguish them as either planktotrophic or lecithotrophic larvae. The assessment of these larval types was based on morphological characteristics of the digestive gland, propodium, and shell. Growth data were analyzed using a 2-tailed t-test, and the number of spawn masses between treatments was compared using a Mann-Whitney test for non-parametric data. Mating Recognition Behavior Adult slugs between 1.3 and 4.1 cm long were col- lected in May 1998 from breeding populations at northern The Veliger, Vol. 45, No. 4 intertidal and southern subtidal sites. I isolated individu- als in covered plastic containers (18.4 X 16.5 x 11.1 cm) at 10°C for at least 5 days prior to the experiment. Three treatment groups consisted of 18 pairs of similarly sized slugs (+1.0 cm). Pairs of adults that were both collected from northern intertidal sites composed one treatment group, another used pairs from southern subtidal sites, and the experimental group consisted of one adult D. frondosus from each of the two habitats. I checked the pairs every hour during a 7-hour period on the first day and a 4-hour period for another 4 days and recorded the number of pairs engaged in copula. Coupling lasted be- tween 2-7 hours, so this monitoring routine was adequate for recording these mating events. I compared frequency counts of mating between the mixed pairs and either the northern intertidal or southern subtidal pairs using a 2 X 2 contingency table with a Log-likelihood ratio (G-test) and a Yates correction for continuity. In addition, I paired four adults from northern subtidal sites: two with indi- viduals from northern intertidal sites and another two with adults from southern subtidal sites. After observing for mating recognition, I then switched pairings to doc- ument the behavior with adults from the other sites (either northern intertidal or southern subtidal). RESULTS Habitats and General Characteristics Southern Subtidal Habitats. D. frondosus is found as- sociated with colonies of Obelia spp. growing on rocky ledges and as epiphytes on the kelps Laminaria spp. and Agarum cribosum (Lambert, 1991). Other nudibranchs common to these communities include Coryphella ver- rucosa, Tergipes tergipes, and Doto coronata. D. fron- dosus at these sites produces only spawn masses with developing planktotrophic larvae. Adult D. frondosus commonly had extensive white or dark brown mottling on a reddish brown body. Northern Intertidal Habitats. D. frondosus is found midway through the protected rockweed zone in dense beds of Ascophyllum nodosum (Gionet & Aiken, 1992; Bleakney, 1996). Here, these slugs are commonly found eating the epiphytic and epilithic hydroid Sertularia pum- ila. The only other nudibranch frequently found in these habitats is a bryozoan feeder, the dorid Acanthodoris pi- losa. D. frondosus is found in rocky crevices at the base of A. nodosum. They deposit spawn masses on the algae and primary substrate, frequently intertwined with the hy- droid colonies. Their color is strictly pale white-yellow, with extremely limited mottling on the dorsal side adja- cent to the cerata. More colorful D. frondosus with ex- tensive mottling can be found infrequently in the littoral zone in southern regions of the Gulf of Maine such as Appledore Island, Maine, but never with the consistency and relatively high densities of those sites in the northern Gulf of Maine. Northern intertidal sites at West Quoddy C. G. Sisson, 2002 Head and Wilbur Neck (Figure 1) always had D. fron- dosus spawn masses that yielded lecithotrophic larvae. No planktotrophic larvae were found in D. frondosus masses at these habitats. Northern Subtidal Habitats. 1 found D. frondosus at subtidal sites in Winter Harbor, Eastport, and Pembroke, Maine (Figure 1) associated with Obelia spp. and related thecate hydroids. These slugs were either reddish brown with white and dark mottling or pale purple or white with limited or no mottling. Collected spawn masses produced either lecithotrophic or planktotrophic larvae depending on the time of year of sampling. Seasonal Spawning and Adult Size Distribution At two southern subtidal sites, York and the Isles of Shoals, D. frondosus had an annual spring spawning event with adults that, when present, were producing spawn masses (Figures 2a, b). After spawning, adult pop- ulations senesced and for several months did not occur at these sites (Figures 2a, b). At two northern intertidal sites, West Quoddy Head and Wilbur Neck, D. frondosus also had an annual spawning period in the spring or early sum- mer (Figures 2c, d); however, new recruits appeared at these sites a few months after the spawning event and gradually increased in size throughout the fall and winter without depositing spawn masses apparently until the fol- lowing spring (Figures 2c, d). Note that there was a brief annual period at the Wilbur Neck site when no D. fron- dosus were found (Figure 2d). The two northern intertidal sites were offset in the timing of these patterns of growth and spawning, with Wilbur Neck having an earlier spawning event than West Quoddy Head (Figures 2c, d). Larval Types and Characteristics No mixed clutches (i.e., both planktotrophic and le- cithotrophic larvae) were found at any of the collection sites. All spawn masses from the two types of D. fron- dosus had one embryo/capsule and each formed a hollow cylindrical capsule-filled cord that was attached along one side, or Type B according to Hurst (1967). All veliger larvae had Type 2 inflated egg-shaped shells (Thompson, 1961). There were large differences in the zygote size, time spent in the embryonic capsule from deposition to hatch- ing, and in larval shell size at hatching (Table 1). Lecith- otrophic larvae began with relatively large zygotes and took approximately a month to hatch. When they did hatch, they were much larger than the planktotrophic lar- vae with a robust velum, a propodium and a visceral mass that occupied a large amount of the larval shell (Figure 3a). When offered microalgae, none were ingested by these veligers or at least were not immediately present in the larval gut. The lecithotrophic veligers began meta- morphosis within a few hours to 1 day of hatching either on the egg mass material or on the hydroids Obelia spp. Page 293 and Sertularia spp. They were never observed metamor- phosing within the embryonic capsule. Planktotrophic veligers originated from smaller zy- gotes, took less time to hatch (approximately 1 week), and were much smaller upon hatching than their lecith- otrophic counterparts (Table 1). These veligers would not metamorphose upon hatching despite the presence of hy- droid material. They actively ingested microalgae when offered it, which was apparent by the presence of red and brown material in the larval gut and digestive gland. The planktotrophic larvae had a shell that was relatively un- filled by larval tissues such as the digestive gland and gut (Figure 3b), and the velum was frequently small with a minimal propodium (Figure 3b). Reciprocal Feeding Experiment Both the northern intertidal and southern subtidal slugs showed less increase in growth on a diet of Sertularia spp. (Figure 4) than on Obelia spp. Although the starting lengths were similar for both trials, the final lengths were much higher for those fed Obelia spp. (Figures 4a, b) and the percent change in lengths was significantly higher for northern intertidal and southern subtidal individuals in this treatment. Similarly, the mean number of spawn mas- ses produced per nudibranch was consistently less for all those fed Sertularia spp. (Figure 4d). The only significant differences for spawn mass output were found for the northern intertidal trial because of high levels of mortality in the southern subtidal treatment group (Figure 4d). De- spite these differences in diet quality, all northern inter- tidal nudibranchs produced spawn masses yielding viable lecithotrophic veligers, and all southern subtidal D. fron- dosus had planktotrophic veligers. Once again, no mixed clutches were deposited. The characteristics presented earlier (Figure 3, Table 1) were used to distinguish these two larval types. Mating Recognition Behavior Adult D. frondosus from northern intertidal and south- ern subtidal habitats did not recognize each other as po- tential mates (Table 2). These slugs did not engage in copula even though others individuals collected at the same sites were actively mating (Table 2). Since only planktotrophic larvae were produced by D. frondosus from southern subtidal sites and only lecithotrophic lar- vae came from those at northern intertidal sites, these crosses reflect the two developmental types. Sperm stor- age from previous mates cannot be ruled out in these trials; therefore, these data do not evaluate fertilization success. These results only represent the potential for be- havioral recognition of adult mates. The limited number of trials with D. frondosus from northern subtidal sites suggests that these individuals mate exclusively with ei- ther the northern intertidal or the southern subtidal adult nudibranchs. None of the four adults from the northern Page 294 The Veliger, Vol. 45, No. 4 fy] Spawning Present but not spawning Absent or unsampled O- York 97 @ York 98 NN — O Shoals 97 @ Shoals 98 3S SEsswe#_e» j 7 S Mean body length (mm) 1 2 3 4 5 6 7 8 9 10 11 12 Figure 2. Mean body length (+ standard deviation, 10 < n < 23) of D. frondosus versus the month of collection in 1997 and 1998 (January = 1, December = 12). Southern subtidal sites are located at (a) Cape Neddick in York, Maine and (b) the Isles of Shoals, New Hampshire. Northern intertidal sites included (c) West Quoddy Head (QH), Maine, and (d) Wilbur Neck (WN) in Pembroke, Maine. Periods of spawning are shaded between consecutive months. C. G. Sisson, 2002 Page 295 Table 1 Morphological and developmental characteristics for planktotrophic and lecithotrophic larvae collected in the Gulf of Maine. Included are the zygote diameter upon deposition, the maximum length of the larval shell and the embryonic capsular period from deposition through hatching. Values include means with the number sampled (n) + standard deviation. Zygote diameters ranged between 85-123 wm for planktotrophic larvae and 183-218 wm for lecithotrophic larvae. Feeding capacity was evaluated with micro-algae in laboratory culture conditions (see Methods). Zygote diameter Capsular period Shell length Larval type (wm) (days) (wm) Feeding capacity Planktotrophic 102 (70) + 12.2 6.7 (11) + 2.5 DAD GID) 28 223) Required Lecithotrophic 194 (70) = 14.8 BDF (22) y8 9. 310 (17) + 49 Incapable subtidal sites would mate with nudibranchs from both of while northern subtidal sites may represent overlapping the other two habitats. populations between the two types. At southern subtidal sites, the irregular size distributions and timing of spawn- DISCUSSION ing events indicate that D. frondosus is a fast-growing, more opportunistic predator with a sub-annual seasonal distribution (Todd, 1981). The most common hydroid at these sites, Obelia geniculata, is extremely ephemeral and may be nearly exhausted by a combination of predators within only a few months (Lambert, 1991). In contrast, the consistent increase in length among northern intertidal populations of D. frondosus followed by a discrete spawning event (Figures 2c, d) indicates that these nu- dibranchs are relatively slow-growing with an annual sea- sonal distribution (Todd, 1981). The most common hy- droid at these sites, Sertularia pumila, is present through- out the year, possibly supplying a constant source of food for these nudibranchs. The senescence of adults after a spawning period (Figures 2c, d) supports the idea of a discrete reproductive event, thus an annual life history pattern (Todd, 1981). The absence of nudibranchs at the Wilbur Neck site following the spawning period (Figure 2d) could be during a period when the larvae are in the water column or when newly recruited individuals are either too small to locate or in a microhabitat different than the adults. These habitats and patterns of feeding ecology have been outlined previously (Meyer, 1971; Clark, 1975; Lambert, 1991; Bleakney, 1996), but not in consideration of the two different larval feeding types produced in these populations and their general biogeo- graphical distribution. Larvae produced from animals collected at these sites had distinctly different characteristics corresponding with habitat and geographic location. D. frondosus produces obligate planktotrophic veliger larvae in southern and northern subtidal habitats. These larvae develop to hatch- ing in a relatively short period of time (Table 1) and may have a longer dispersal potential, corresponding with the opportunistic, highly seasonal occurrence of adult popu- There are two disparate life history patterns for D. fron- dosus in the Gulf of Maine. These patterns are most ev- ident at southern subtidal and northern intertidal sites, Figure 3. Light micrographs of D. frondosus larvae (bar = 100 9 . 2 9 ; wm). a. Lecithotrophic veliger larva from the northern Gulf of etlons. Lectinomoplue weliger lene ame ipteewees) |) Maine. b. Planktotrophic veliger larva from the southern Gulf of populations in northern intertidal and northem subtidal Maine. S = shell, V = velum, P = propodium, M = metapo- habitats, and show the potential for limited dispersal by dium. metamorphosing in response to the egg mass jelly. This Page 296 The Veliger, Vol. 45, No. 4 a) b) 50 25 | me Obelia | 40 - Sertularia | 20 | # * = ‘eo € £ 30) ale is 4 fe s is — od) 2 20 - 2 10, g a 10 | So - 0 1 0 : NI Startlength —_— Final length SS Start length Final length c) d 300 + ) n c 250 1 > 6 3] @ 2004 S [= ne} oD we 7 va no) 1G) A ic =} 3 Ae ve ES | <= Oo 504 : = 41 x rs) B= 0 A , 0 NI Ss NI Ss Figure 4. Results from reciprocal feeding experiment with Obelia sp. and Sertularia sp. fed to D. frondosus collected from northern intertidal (NI) and southern subtidal (SS) sites. All results are mean values (+ standard deviation) and all comparisons are with a two- tailed t-test, except for the non-parametric Mann-Whitney test for spawn mass products. a. Starting (Nope = 30, Dserutaria = 30, t = 0.545, df = 58, P = 0.59) and finishing (Ngyeiqg = 22. Osenuiaria = 29, t = 4.82, df = 49, P < 0.001) lengths for NI trial. b. Starting (Nopetia = 255 Dsermaria = 24, t = 0.533, df = 47, P = 0.60) and finishing (Noycig = 23, Nsertaria = 12, t = 6.63, df = 33, P< 0.001) lengths for SS trial. c. Percent change in length (change in length/initial length) for NI (t = 3.72, df = 49, P < 0.001) and SS (t = 3.83, df = 33, P < 0.001) trials. d. Mean number of spawn masses (s.m.)/nudibranch produced by individuals fed the two treatment diets for NI (U = 235, P < 0.001) and SS (U = 9.0, P > 0.10) trials. response is similar to that found for other opisthobranchs Table 2 (Gibson & Chia, 1989; Chester, 1996) and although the Results of mating recognition behavior crosses between ability to delay metamorphosis (Pechenik, 1990) may still D. frondosus from northern intertidal (NI) and southern exist, this limited dispersal potential corresponds with the subtidal (SS) sites. Northern intertidal adults always pro- year-round persistence of adults and may be adaptive for duced lecithotrophic larvae and southern subtidal adults a seasonally constant food source. always produced planktotrophic larvae. * Denotes signif- Characteristics of egg size and capsular period directly icant difference (G, = 9.1, p < 0.05). + Denotes signifi- correlate to larval feeding types among nudibranchs cant difference (G, = 26.6, p < 0.05). (Todd, 1981). Zygote diameters in this study were similar to published values for planktotrophic (Clark, 1975; Copulation : : j G ann, d lec roph ligers (Th - Cross observed No copulation Total # trials Stathmann : eH) oe SOROS Ne 18 Bee son, 1967) for D. frondosus. Capsular periods were also 2 ae : : i. in the range of published values for planktotrophic (Hurst, Ss x Sst 15 3 18 1967; Williams, 1971) and lecithotrophic (Thompson, 1967) D. frondosus veligers. No mixed clutches were C. G. Sisson, 2002 found in any of the habitats, and zygote diameters and capsular periods did not overlap (Table 1). The dichotomous nature of these characteristics sug- gests that D. frondosus has limited phenotypic plasticity with regard to larval feeding type. In one of the clearest examples of poecilogony, Krug (1998) found mixed clutches of lecithotrophic and planktotrophic larvae in populations of the ascoglossan opisthobranch Alderia mo- desta. Other cases of poecilogony have documented geo- graphically separated populations of a species with dif- ferent larval types where the adults can interbreed (Levin, 1984; West et al., 1984). The lack of mating recognition between individuals from the populations of D. frondosus described in this paper (Table 2) appears to preclude this type of poecilogony. Quality of adult diet and feeding history has been shown to be an important factor resulting in shifts in lar- val type for poecilogonous species (Krug, 1998) and changes in capsular period (Gibson & Chia, 1995; Ches- ter, 1996). In this study, reciprocal feeding experiments with adults fed the lower quality diet of Sertularia spp. from intertidal habitats and the higher quality Obelia spp. from subtidal habitats did not result in any differences in the resulting larval type. Higher growth rates were mea- sured for both types of D. frondosus when fed Obelia spp., and a high level of mortality was recorded for the Sertularia treatment group, especially for the southern subtidal trial. Reduced production of spawn masses on a lower quality diet (Sertularia spp.) indicates some gross changes in reproductive effort. Unfortunately, zygote di- ameters were not measured in these experiments, nor were there any direct measurements of reproductive out- put in response to these treatments. However, the lack of shift in larval feeding types in response to adult diets of differing quality suggests that this remains a fixed trait for these nudibranch types, and poecilogony is unlikely for D. frondosus in the Gulf of Maine. It is important to note here the variation in diameters of zygotes from an- imals collected in the field despite the consistent disparity between feeding requirements of the resultant larvae (Ta- ble 1). Although these life history patterns are dichoto- mous, there may be considerable variation surrounding each developmental mode. Still, there appears to be little evidence for poecilogony for D. frondosus in the Gulf of Maine. Given the differences in larval type and seasonal pat- terns of adult occurrence, the separation of populations of this species may not be explained simply by pheno- typic plasticity of reproductive traits. This study also evaluated the potential for mating behavior between adults in the northern intertidal and southern subtidal pop- ulations. Other mating recognition studies have been used to help clarify sibling species complexes and indicate a strong possibility for reproductive isolation between the two most extreme groups (Hirano & Hirano, 1991; Lan- gan-Cranford & Pearse, 1995). Dendronotus frondosus Page 297 adults collected from northern intertidal and southern subtidal sites in the Gulf of Maine do not recognize each other as potential mates, representing a distinct reproduc- tive isolation mechanism between these two populations. Only a limited number of replicates from northern sub- tidal populations were attempted and these yielded similar results by dividing the two reproductive patterns. These data also suggest that the northern subtidal habitat may support sympatric populations of the two types of D. frondosus corresponding with the presence of both plank- totrophic and lecithotrophic larvae. The division of life history patterns, larval morpholo- gy, and mating recognition behavior is motive for a for- mal taxonomic review of D. frondosus in the Gulf of Maine. This review should include molecular genetic data, comparisons of the radula and reproductive system, and a thorough reanalysis of the literature for the history of this genus in the north Atlantic. Acknowledgments. I thank Dr. L. Harris for his generous sup- port of this research. Dr. S. Chavanich and C. Williams helped with diving and intertidal field collections. Drs. L. Harris, C. Walker, C. Cohen, A. Stork, and two anonymous reviewers pro- vided valuable comments on earlier drafts. This research was submitted in part toward the completion of an M.S. thesis in Zoology at the University of New Hampshire, Durham, and par- tially supported by research grants from the UNH Graduate School and Center for Marine Biology. LITERATURE CITED ALDER, J. & A. HANCOCK. 1845-1855. A Monograph of the Brit- ish Nudibranchiate Mollusca. I-VI. Ray Society: London. BLEAKNEY, J. S. 1996. Sea Slugs of Atlantic Canada and the Gulf of Maine. Nimbus Publishing and the Nova Scotia Museum: Halifax, Nova Scotia. 216 pp. BOoucHET, P. 1989. A review of poecilogony in gastropods. Jour- nal of Molluscan Studies 55:67—78. CHESTER, C. M. 1996. The effect of adult nutrition on the repro- duction and development of the estuarine nudibranch, Te- nellia adspersa (Nordmann, 1845). Journal of Experimental Marine Biology and Ecology 198:113—130. CLARK, K. B. 1975. Nudibranch life cycles in the Northwest At- lantic and their relationship to the ecology of fouling com- munities. 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A. & T. S. Bripces. 1995. Pattern and diversity in reproduction and development. Pp. 1—48 in L. R. McEdward (ed.), Ecology of Marine Invertebrate Larvae. CRC Press: Boca Raton, Florida. MACFARLAND, F. M. 1966. Studies of opisthobranchiate mollusks of the Pacific Coast of North America. Memoirs of the Cal- ifornia Academy of Sciences 6:1—546. McDOoNaLp, G. & J. NYBAKKEN. 1999. A worldwide review of the food of nudibranch mollusks. Part I. The suborder Den- dronotacea. The Veliger 42(1):62—66. Meyer, K. B. 1971. Distribution and zoogeography of fourteen species of nudibranchs of northern New England and Nova Scotia. The Veliger 14(2):137—152. MILLER, M. C. 1961. Distribution and food of the nudibranchiate Mollusca of the south of the Isle of Man. Journal of Animal Ecology 30:95-116. PECHENIK, J. A. 1990. Delayed metamorphosis by larvae of ben- The Veliger, Vol. 45, No. 4 thic marine invertebrates: does it occur? Is there a price to pay? Ophelia 32(1—2):63—94. ROBILLIARD, G. A. 1970. The systematics and some aspects of the ecology of the genus Dendronotus. The Veliger 12(4): 433-479. ROBILLIARD, G. A. 1975. The nudibranch Dendronotus frondo- sus—one species or four? The Festivus 6(8):44—47. STRATHMANN, M. E 1987. Reproduction and Development of Ma- rine Invertebrates of the Northern Pacific Coast. University of Washington Press: Seattle. 670 pp. SWENNEN, C. 1961. Data on the distribution, reproduction and ecology of the nudibranchiate molluscs occurring in the Netherlands. Netherlands Journal of Sea Research 1:191— 240. THOLLESSON, M. 1998. Discrimination of two Dendronotus spe- cies by allozyme electrophoresis and the reinstatement of Dendronotus lacteus (Thompson, 1840) (Nudibranchia, Dendronotoidea). Zoologica Scripta 27(3):189-195. THompson, T. E. 1961. The importance of the larval shell in the classification of the Sacoglossa and the Acoela (Gastropoda Opisthobranchia). Proceedings of the Malcological Society of London 34(5):233-238. THOMPSON, T. E. 1967. Direct development in a nudibranch, Cad- lina laevis, with a discussion of developmental processes in Opisthobranchia. Journal of the Marine Biological Associ- ation of the United Kingdom 47:1—22. THOMPSON, T. E. & G. H. BRown. 1984. Biology of Opistho- branch Molluscs. Ray Society: London. 229 pp. Topp, C. D. 1981. The ecology of nudibranch molluscs. Annual Review of Oceanography and Marine Biology 19:141—234. West, H. H., J. FE HARRIGAN & S. K. PIERCE. 1984. Hybridization of two populations of a marine opisthobranch with different developmental patterns. The Veliger 26(3):199—206. WILLIAMS, L. G. 1971. Veliger development in Dendronotus frondosus (Ascanius, 1774) (Gastropoda: Nudibranchia). The Veliger 14(2):166-171. The Veliger 45(4):299—302 (October 1, 2002) REE AV BEIGER © CMS, Inc., 2002 A New Species of Granigyra Dall, 1889 (Gastropoda: Skeneidae) from Brazil and a Review of Known Western Atlantic Species PAULINO JOSE SOARES bE SOUZA, Jr! AnD ALEXANDRE DIAS PIMENTA? ' Museu de Zoologia, Universidade de Sao Paulo. P. O. Box 42694, Sao Paulo, SP, CEP: 04299-970, Brazil; pjsouza@ yahoo.com * Departamento de Zoologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, CEP: 21941-570, Brazil; alexpim @biologia.ufrj.br Abstract. Granigyra oblatogyra, sp. nov. is described based on the shell morphology of seven individuals collected between 510-1250 m off the Brazilian coast. It is characterized by its apically flattened whorls and anteriorly projected aperture. A brief review of the three previously known west Atlantic species is presented. The lectotype of G. radiata Dall, 1927, (herein designated), and the holotype of G. spinulosa (Bush, 1897) are illustrated by SEM for comparison with the new species. INTRODUCTION The genus Granigyra Dall, 1889, comprises a group of minute, trochoid “‘skeneimorph”’ gastropods character- ized by a sandlike granulation on the shell surface. They are known only from bathyal and abyssal depths, and species are reported primarily from the Atlantic ocean, with a single species from Sumatra (Warén, 1992, 1993). In the western Atlantic, there are species described: G. radiata Dall, 1927, from Florida, USA; G. spinulosa (Bush, 1897), from the Bahamas: and G. limata (Dall, 1889), from Cuba. The taxonomic position of the genus Granigyra is con- troversial. Hickman & McLean (1990) and Hickman (1998) treated Skeneidae as a polyphyletic assemblage of minute-shelled, non-nacreous taxa of widely differing radular morphology, where many genera might reside provisionally. Warén (1992) adopted a more narrow def- inition that included a turbinid-like radula and the pres- ence of a unique propodial penis. Although Warén (1992, 1993) found these features lacking in Granigyra, he re- tained the genus provisionally in Skeneidae. In the pre- sent study, we follow this provisional classification. Herein we describe a new species of Granigyra col- lected by dredging carried out during oceanographic ex- peditions along the Brazilian coast. This is the first record of this genus from Brazilian waters, and review of the other western Atlantic species. In the description section, diameter and number of protoconch whorls were mea- sured following Leal (1991). Abbreviations used through the text: ANSP—Academy of Natural Sciences of Philadelphia, Philadelphia; IB- UFRJ—Instituto de Biologia/Universidade Federal do Rio de Janeiro, Rio de Janeiro; JOPS—Joint Oceano- graphic Projects, Research Vessel Victor Hansen coll; MNHN—Muséum National d'Histoire Naturelle, Paris; MNRJ—Museu Nacional/Universidade Federal do Rio de Janeiro, Rio de Janeiro, MORG—Museu Oceanografico “Eliézer de Carvalho Rios,”’ Rio Grande; MZSP—Museu de Zoologia da Universidade de Sao Paulo, Sao Paulo; PUC—Pontificia Universidade Catélica do Rio de Janei- ro, Rio de Janeiro; USNM—National Museum of Natural History, Washington, DC; YPM—Peabody Museum of Natural History/Yale University, New Haven. SYSTEMATICS [?] Family SKENEIDAE Clark, 1851 Genus Granigyra Dall, 1889 Type species by monotypy Cyclostrema (Granigyra) limatum Dall, 1889 Granigyra oblatogyra de Souza & Pimenta, sp. nov. Figures 1—4 Type material: Holotype: MNRJ 8433, off Rio Doce, Espirito Santo State (JOPS #3228:19°45.5'S, 038°45.8'W, 1100 m), length: 2.5 mm, width: 2.4 mm; paratypes: USNM 894863 (JOPS #3228: 19°45.5’S, 038°45.8'W, 1100 m), length: 1.5 mm, width: 1.4 mm; IBUFRJ 11019, off Macaé, Rio de Janeiro State (22°41'25.36’S, 040°26'49.19”W, 780 m), length: 2.3 mm, width: 2.2 mm; MNHN, off Rio Doce, Espirito Santo State (JOPS #3221: 19°50.6'S, 0.39°34.8'W, 510 m), length: 1.6 mm, width: 1.5 mm (lip broken); ANSP 407933, off Macaé, Rio de Janeiro State (22°37'48.62"S, 043°22'50.14”"W, 720 m), length: 2.0 mm, width: 2.0 mm (protoconch broken); MORG 41034, off Macaé, Rio de Janeiro State (22°37'48.62”S, 043°22'50.14”W, 720 m), length: 1.5 mm, width: 1.4 mm; MZSP 32870, off Macaé, Rio de Janeiro State (22°36'52.65"S, 040°40'25.25”W, 1250 m), length: 1.6 mm, width: 1.6 mm. Type locality: off Rio Doce, Espirito Santo State (JOPS #3228: 19°45.5'S, 038°45.8'W, 1100 m), Brazil. Page 300 Range: Espirito Santo State to north of Rio de Janeiro State, Brazil. Diagnosis: Species with apically flattened whorls and an- teriorly projected aperture. Description: Shell medium sized for the genus (holotype: length:2.5 mm; width:2.4 mm), turbiform. Surface white, covered with somewhat coarse granulation. Granules in- creasing in size, following the growth of the shell, resem- bling striated mountain peaks with flat tops, and much smaller granules in between them (Figure 2). Protoconch (Figure 4) small (diameter: about 220 ym), covered with very fine irregular granules, with about one whorl. Teleo- conch with 2.5 distinctively rounded, posteriorly flattened whorls that increase rapidly in diameter; connection with previous whorls narrow. Aperture rounded, holostomate, slightly elliptical, projecting slightly anteriorly, with a flat, posterior shoulder next to suture. Umbilicus narrow, slitlike, deep. Etymology: This species is named after its posteriorly flattened whorls (oblata = flattened at the poles; gyra = turn). Granigyra limata (Dall, 1889) Cyclostrema (Granigyra) limatum Dall, 1889:395 [holotype: USNM 214280, Blake sta. 19, off Bahia Honda, Cuba]. Granigyra limata (Dall, 1889): Dall, 1927:123; Abbott, 1974:56; Warén, 1992: 175, fig. 31E. Lissospira (Ganesa sect. Granigyra) limata Bush, 1897: 135. Granigyra spinulosa (Bush, 1897) (Figures 5, 6) Lissospira (Ganesa sect. Granigyra) sipinulosa Bush, 1897: 135 [holotype: YPM 15805, USFC sta. 2655 (27°22'N, 078°07'30"W)]. Granigyra spinulosa (Bush, 1897): Abbott, 1974:56; John- son, 1989:65, pl. 10 fig. 1. Granigyra radiata Dall, 1927 (Figures 7, 8) Granigyra radiata Dall, 1927:123 [lectotype: USNM 108138, off Fernandina, Florida (herein designated)]; Abbott, 1974:56; Warén 1992: 175, fig. 31E. Remarks: We designate the lectotype of G. radiata, as the genus Granigyra comprises small somewhat similar The Veliger, Vol. 45, No. 4 species that may lead to confusing identifications. The species is illustrated for the first time. Discussion: See Warén (1992) for synonymy and taxonomic discussion of the genus. Granigyra oblatogyra has ellipsoid, and posteriorly flattened whorls that distinguish it from G. limata (holo- type figured in Warén, 1992:232, fig. 31E) that also has much coarser granulation on the body whorl. The higher shell profile and the ellipsoid, posteriorly flattened whorls of G. oblatogyra distinguish it from G. spinulosa (Figures 5, 6). In G. spinulosa the contact be- tween whorls is wider, and the umbilicus is wider than in G. oblatogyra. Granigyra oblatogyra has more convex whorls, a deep- er Suture, and thinner granulation than G. radiata (Figures 7, 8). Granigyra radiata also has coarse granules irreg- ularly fused into radially oriented ridges almost parallel to growth lines (Figures 7, 8). In addition to the western Atlantic species, there are four species in the eastern Atlantic, and one from Sumatra (Warén, 1992, 1993). The most similar to G. oblatogyra is G. granulifera Warén, 1992:236, figs. 35A—E, but it differs by its nearly to totally disjunct whorls, lower pro- file, and thinner, less dense granulation. Acknowledgments. We are grateful to Dr. E. Lazo-Wasen (YPM) for the loan of the holotype of G. spinulosa; Dr. M. Har- asewich and Mr. P. Greenhal (USNM) for providing us with the scanning electron micrographs of the lectotype of G. radiata; Dr. R. Absalao (IBUFRJ) for providing the specimens of G. obla- togyra; Ms. M. E Lopes (PUC-RJ) and Lara Guimaraes (MZSP) for the scanning electron micrographs of the new species; Dr. R. Absalao (IBUFRJ), Dr. C. Hickman, and an anonymous reviewer for their helpful comments on the manuscript. The senior author was funded by doctoral grant FAPESP (‘‘“Fundagao de Amparo a pesquisa do Estado de Sao Paulo”’) 97/11429-3. This study was partially supported by CNPq. (““Conselho Nacional de Desen- volvimento Cientifico e Tecnoldgico’’). LITERATURE CITED ABBoTT, R. T. 1974. American Seashells. 2nd ed. Van Nostrand Reinhold Company: New York. 663 pp., 24 pls. Busu, K. J. 1897. Revision of the marine gastropods referred to Cyclostrema, Adeorbis, Vitrinella, and related genera; with descriptions of some new genera and species belonging to the Atlantic fauna of America. Transactions of the Connect- icut Academy of Arts and Sciences 10:97—144, pls. 22, 23. DALL, W. H. 1889. Reports on the results of dredging, under the Figures 1-8. Figures 1-4. Holotype of Granigyra oblatogyra de Souza & Pimenta, sp. nov. Figure 1. Apertural view (length: 2.7 mm; width: 2.4 mm). Figure 2. Detail of sculpture, scale 50 4m. Figure 3. Ventral view. Figure 4. Detail of protoconch, scale 50 um. Figures 5, 6. Holotype of Granigyra spinulosa Bush, 1897. Figure 5. Apertural view (length: 2.3 mm; width: 2.2 mm). Figure 6. Detail of protoconch, scale 50 um. Figures 7, 8. Lectotype of Granigyra radiata Dall, 1927. Figure 7. Apertural view (length 2.0 mm; width: 1.9 mm). Figure 8. Dorsal view, showing protoconch and radial sculpture. P. J. Soares de Souza & A. D. Pimenta, 2002 Page 302 supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78), by the U.S. Coast Survey Steamer “Blake,” Lieut-Commander C. D. Sigsbee, U.S.N., and commander Bartlett, U.S.N., commanding. Bulletin of the Museum of Comparative Zoology 29(2):1—492, pls. 10—40. DALL, W. H. 1927. Small shells from dredgings off the southeast coast of the United States by the United States Fisheries steamer ‘“‘Albatross’’ in 1885 and 1886. Proceedings of the U.S. National Museum 70 (2667):1—134. HICKMAN, C. 1998. Family Skerneidae. Pp. 690-691 in P. L. Beesley, G. J. B. Ross & A. Wells (eds.), Mollusca: the Southern Synthesis. Fauna of Australia. Vol. 5. CSIRO Pub- lishing: Melbourn. Hickman, C. S. & J. H. MCLEAN. 1990. Systematic revision and The Veliger, Vol. 45, No. 4 suprageneric classification of trochacean gastropods. Science Series, Natural History Museum of Los Angeles County 35: 1-169. JOHNSON, R. I. 1989. Molluscan taxa of Addison Emery Verrill and Katherine Jeannette Bush, including those introduced by Sanderson Smith and Alpheus Hyatt Verrill. Occasional Pa- pers on Mollusks 5 (67):1—143. LEAL, J. H. 1991. Marine Prosobranch Gastropods from Oceanic Islands off Brazil. Universal Book Services: Dr. W. Back- huys: Oegstgeest. 1-418. Waren, A. 1992. New and little known “‘skeneimorph”’ gastro- pods from the Mediterranean Sea and the adjacent Atlantic Ocean. Bollettino Malacologico 27:149-247. Waren, A. 1993. New and little known Mollusca from Iceland and Scandinavia. Part 2. Sarsia 78:159—201. The Veliger 45(4):303—308 (October 1, 2002) tHe yy ELIGER © CMS, Inc., 2002 A New Species of Attiliosa (Muricidae: Neogastropoda) from the Upper Eocene/Lower Oligocene Suwannee Limestone of Florida GREGORY S. HERBERT Department of Geology and Center for Population Biology, University of California, Davis, California 95616, USA; herbert @ geology.ucdavis.edu ROGER W. PORTELL Invertebrate Paleontology Division, Florida Museum of Natural History, University of Florida, P. O. Box 117800, Gainesville, Florida 32611-7800, USA; portell@ fimnh.ufl.edu. Abstract. Attiliosa aenigma, sp. nov., a muricine muricid, is described from the shallow water, carbonate paleoen- vironment of the uppermost Eocene/lowermost Oligocene Suwannee Limestone of Florida. This new species predates all other New World species of Attiliosa Emerson, 1969, by roughly 15 ma and is contemporaneous with, or slightly older than, the oldest known fossil species of Afttiliosa from the Old World. This new occurrence indicates that phylo- genetic diversification and geographic range expansion in Aftiliosa took place much earlier than previously thought. Attiliosa aenigma, sp. nov. is most similar in morphology to the Recent A. bozzettii Houart, 1993, from Somalia. Both have up to four nodules on the anterior portion of the columella, a posterior channel along the outer lip of the aperture, and fine, closely spaced and paired cords on the upper portion of the body whorl. This latter feature has not been described in muricine muricids until now, although it may have significance for muricine phylogeny. INTRODUCTION In a series of papers revising the systematics and fossil history of the muricid genus Afttiliosa Emerson, 1968, E. Vokes proposed that Aftiliosa likely originated in the Old World from within the Poirieria clan of the muricid sub- family Muricinae (Vokes, 1971, 1976, 1988, 1989, 1992, 1999; Vokes & D’Attilio, 1982). In support of this hy- pothesis, Vokes noted potential synapomorphies in the shells of both fossil and Recent Poirieria (Panamurex) Woodring, 1959, and Aftiliosa, such as the presence of columellar nodules and labral lirations in the aperture, and general similarities between the radulae of living spe- cies of Attiliosa and Poirieria (Vokes, 1976, 1992, 1999). Vokes’ revision of the Afttiliosa fossil record has also shown that the earliest geological occurrence of the genus is an undescribed species from the early Oligocene of France. The oldest Aftiliosa in the fossil record of the Americas reported by Vokes is from the late early Mio- cene Chipola Formation of Florida (Vokes, 1989, 1992, 1999). In the present study, we describe an enigmatic new species of muricid gastropod from the latest Eocene/ear- liest Oligocene of Florida, which we refer tentatively to the genus Afttiliosa. This new fossil species predates all other New World Attiliosa by at least 15 ma, and it is roughly contemporaneous with, or possibly even slightly older than, the oldest known species of Aftiliosa in the fossil record from France. In addition, we discuss the pa- leoecology of the Suwannee Limestone in order to pro- vide general information on the ecology and habitats pre- sent. Finally, we report a previously undocumented shell character found in certain members of the Poirieria clan, which may offer further insight into the phylogeny and evolutionary history of this problematic group. GEOLOGY Aanp PALEOECOLOGY The most diverse Paleogene molluscan fauna known from Florida (Mansfield, 1937, 1939; Vokes, 1992; Petuch, 1997) occurs at a now disused limestone quarry infor- mally named Terramar 01 (= University of Florida [UF] locality POO17). The quarry is located approximately 9.7 km northwest of Socrum, S 1/4, sec. 10, T. 26 S, R. 22 E, Socrum Quadrangle USGS 7.5’ series (1987), Polk County, Florida (Figure 1). Intensive collecting of spoil piles near the water-filled quarry by staff and volunteers of the Florida Museum of Natural History (FLMNH) from 1988 until 1992 yielded numerous silicified inver- tebrate taxa as well as remains of sirenians and fishes (primarily sharks). During de-watering of the pit in 1990, R.W.P. observed in situ, a fine-grained, white limestone underlying an upper silicified zone containing numerous completely or incompletely silicified pseudomorphs of Foraminifera, Cnidaria, Bryozoa, Mollusca, and Echino- dermata. Based on lithology and the abundant presence TERRAMAR ©1 (PO@17) = \ * , BARTOW POLK COUNTY _——L— =) 20 40km Figure 1. Map of Florida showing location of Terramar 01 (= km northwest of Socrum, Polk County, Florida. of the irregular echinoid Rhyncholampas gouldii (Bouvé) throughout the white limestone and silicified zone and the strombid gastropod Orthaulax hernandoensis Mansfield, in the silicified zone, the unit was referred to the Suwan- nee Limestone. Cooke & Mansfield (1936) originally defined the Su- wannee Limestone as a hard, crystalline, yellowish lime- stone exposed along the Suwannee River near Ellaville, Florida with fossils of Cassidulus gouldii (= Rhyncho- lampas gouldii). Typically, the formation is a white to pale orange, soft, and porous wackestone, packstone, or grainstone with loosely cemented foraminifera, common echinoids, and rare to locally abundant mollusks. Mod- erate variation in lithology exists in the formation The Veliger, Vol. 45, No. 4 University of Florida [UF] locality POO17). The quarry is located 9.7 throughout its areal distribution, and induration varies from incompletely cemented to highly cemented to silic- ified. The Suwannee Limestone is exposed intermittently at the surface from central peninsular Florida to the east- ern panhandle region and has been recorded in the sub- surface as far south as Key West (Bryan, 1991). Brewster-Wingard et al. (1997) provided an age esti- mate for the deposition of the Suwannee Limestone of peninsular Florida using an integrated approach of litho- stratigraphic, biostratigraphic (primarily mollusks and dinocysts), and chronostratigraphic (Strontium isotopes) analyses. They determined the Suwannee Limestone to have a depositional age of 36.9 to 30.9 ma (+1-—3 ma), which they considered early Oligocene based on the time G. S. Herbert & R. W. Portell, 2002 Page 305 scale of Berggren et al. (1985). A revised Cenozoic geo- chronology presented by Berggren et al. (1995) now plac- es the Eocene/Oligocene boundary at 33.7 ma; thus, de- position of the Suwannee Limestone may have begun during the late Eocene. Although the Brewster-Wingard et al. (1997) study did not analyze Terramar 01 material, Jones et al. (1993) determined an *’Sr/*°Sr isotope age for the Suwannee Limestone at Terramar to be 33.6 to 34.1 ma (+0.5—1.0 ma) based on analysis of asteroid (cf. Gon- iodiscaster sp.) marginal ossicles. Following the time scale of Berggren et al. (1995), the Jones et al. (1993) strontium dates indicate the Suwannee Limestone at Ter- ramar (01 straddles the Eocene/Oligocene boundary. The environment of deposition of the Suwannee Lime- stone was essentially like that found today off the Florida keys with a shallow water, marine environment floored with carbonate sands and mud and inhabited by a wide range of invertebrates, including corals (Cooke, 1945; Randazzo, 1972; Bryan, 1991; Petuch, 1997). This is gen- erally consistent with what is known of habitat occur- rences for modern species of Aftiliosa, which are com- monly collected from 20-30 m depth under coral rubble (Vokes, 1989, 1992, 1999). Several Suwannee Limestone localities contain coral-dominated buildups; and abundant branches of Stylophora sp., massive colonies of Sider- astrea sp., and large heads of Astrocoenia sp. have been reported from Terramar 01 (Bryan, 1991). However, based on the common remains of dugongs (sea cows) and the low diversity of branching and massive colonial cor- als at Terramar 01, the paleoenvironment probably com- prised a patch reef and/or coral thickets with sea grass beds, not true reef tracts (Bryan, 1991). Petuch (1997) reported four main substrate types at Terramar 01: bio- herms of Stylophora; deeper lagoonal open bottom areas; sea grass beds; and very shallow water oyster beds and intertidal mud flats. While Petuch’s interpretation of the paleoecology represented by this fauna generally agrees with prior interpretations, it must be pointed out that near- ly all the material obtained from Terramar 01 was col- lected as spoil and that material collected in situ during de-watering in 1990 indicated transport. No paired valves of bivalves were found, no preferred orientations were observed, and invertebrate taxa representing different habitats were jumbled together. Clearly, either relatively high wave or current action, as indicated by the presence of small-scale cross beds (Huddlestun, 1993), played a role in the formation of this deposit. Furthermore, Pe- tuch’s report of an unmapped and still-unstudied Oligo- cene coral reef tract that developed farther to the west of Terramar O01 is unsubstantiated. SYSTEMATIC PALEONTOLOGY The following locality number and catalogued specimens are those of the Invertebrate Paleontology Division, Flor- ida Museum of Natural History (FLMNH), University of Florida, Gainesville (collection acronym UF), and the In- stitut royal des Sciences naturelles de Belgique (IRSNB). Class GASTROPODA Order NEOGASTROPODA Superfamily MURICACEA Family MurIciDAE Rafinesque, 1815 Subfamily MurRICINAE Rafinesque, 1815 Genus ATTILIOSA Emerson, 1968 Type species: Coralliophila incompta Berry, 1960 (= Peristernia nodulosa A. Adams, 1855), by original des- ignation. Attiliosa aenigma Herbert & Portell, sp. nov. (Figures 2a—d) Material examined: Holotype (UF 103371). Height 17.1 mm; maximum diameter 10.3 mm. Type locality: UF locality POO17, Terramar 01 (West Coast Mine), 9.7 km northwest of Socrum, Socrum Quad- rangle USGS 7.5’ Series (1987), S 1/4, sec. 10, T. 26 S, R. 22 E, Polk County, Florida. Collected from spoil by Roger Portell and Kevin Schindler, November 1989. Stratigraphic distribution: Known only from the type locality. Etymology: aenigma (L.) = a mystery or puzzle. A ref- erence to our tentative assignment of the new species to the genus Aftiliosa. Description: Shell of average size for genus, body whorl inflated. Protoconch and early teleoconch whorls eroded. Spire low, with six visible teleoconch whorls. Spire, last body whorl, and canal (incomplete) each approximately one-third of total shell height. Axial ornamentation com- prising nine, thick, rounded ribs on earliest teleoconch whorls, reduced to seven on final whorl. Ribs strong over entire last body whorl, arch-shaped, adherent to previous whorl, and converging with other ribs at suture and tip of siphonal canal. Spiral ornamentation on early whorls not visible due to worm nature of holotype. Final whorl with 15 primary cords of approximately equal strength. Cords paired on adapical portion of penultimate and last whorls. Aperture broad posteriorly, constricted anteriorly. Abapical portion of columella with three or four nodules, the adapical-most nodule being strongest and slightly sep- arated from remaining ones. Low parietal ridge formed by protuberance of rib from previous whorl. Parietal shield broad, adherent to whorl, and flattened ventrally over its abapical half. Adaxial margin of outer lip with eight strong lirae becoming obsolete within. Lirae visible again farther back inside aperture (~ 5 mm from edge of Page 306 The Veliger, Vol. 45, No. 4 Figure 2. Attiliosa aenigma Herbert & Portell, sp. nov. UF 103371 (Holotype); height 17.1 mm, maximum diameter 10.3 mm. Locality: Terramar 01 (POO17), Suwannee Limestone, Polk County, Florida. a. Apertural view. b. Abapertural view. c. View of fine, closely spaced, paired cords on the upper portion of the body whorl. d. Apertural view showing presence of columellar nodules. aperture) corresponding to resting point at previous lip. Adapical-most lira within aperture separated from ante- rior seven, delineating a shallow posterior canal. Lower tip and abaxial lip of canal missing. Pre-terminal canals visible over last whorl indicating canal constricted, short, and recurved distally, forming a shallow pseudoumbili- cus. Discussion: We assign the new species, Afttiliosa aenig- ma, to the Muricinae based on conchological similarities between the holotype and members of the Poirieria clan, particularly Poirieria (Panamurex) Woodring, 1959; Cal- otrophon Hertlein & Strong, 1951; Dermomurex (Takia) Kuroda, 1953; and Aftiliosa Emerson, 1968. As in the new species, members of these genera tend to be small (10-30 mm) with inflated body whorls; a broad aperture with a broad parietal shield; lirae on the adaxial margin of the outer apertural lip; six to nine archlike axial ele- ments of equal strength, which extend from the suture to the tip of the siphonal canal; and an open and slightly recurved siphonal canal. The combined presence of three additional morpholog- ical features of the teleoconch whorls, however, is con- sistent only with an assignment of the new species to the genus Afttiliosa. The fine, closely spaced, and paired cords on the upper portion of the body whorl of the new species (Figure 2c), for example, are found in a number of spe- cies of Attiliosa (Vokes, 1999: figs. 1, 41) and Takia (Vo- kes, 1975: pl. 5, fig. 4; Vokes, 1992: pl. 18, figs. 8, 9) but not Panamurex or Calotrophon (Vokes, 1992). The presence of columellar nodules in the new species (Figure 2d) is also characteristic of Afttiliosa, as well as Pana- murex and Calotrophon, but no columellar nodules of this type are found in any species of Takia (Vokes, 1992). Lastly, a posterior channel formed along the posterior portion of the aperture in the new species (Figure 2d) is found in several species of Attiliosa (Vokes, 1999: figs. G. S. Herbert & R. W. Portell, 2002 Page 307 Figure 3. Attiliosa bozzettii Houart, 1993. IRSNB 1G27.873/ 454 (Holotype); height 17.0 mm, maximum diameter 10.1 mm. Locality: Ras Hafun, Somalia, 150-200 m. a. Apertural view. b. Abapertural view. (Photographs courtesy of R. Houart) 2, 5, 7) and at least in one species of Calotrophon (Vokes, 1992: pl. 19, fig. 11), but no clearly delineated posterior channels are formed in species of Panamurex or Takia. Despite this consistency, we regard our generic place- ment as tentative due to the low number of potentially informative characters in the type material. This problem is attributable, in part, to poor preservation, since the pro- toconch and early teleoconch whorls are missing in the holotype. More problematic, however, is the relatively simple morphology of the new species, a condition that characterizes a number of sub-lineages within the Poiri- eria clan and has been a prime source of systematic con- fusion in the Muricinae (Vokes, 1992, 1999). Strength- ening our position somewhat is the close morphological resemblance of A. aenigma to the living Afttiliosa bozzettii Houart, 1993 (Figure 3) from deep waters off the coast of Somalia. Both A. aenigma and A. bozzettii exhibit paired (or bisected) cords, a rounded rather than a shoul- dered body whorl, and up to four rather than only three columellar nodules, although these characters vary some- what in A. bozzettii (Roland Houart, 2001, personal com- munication). These species differ in the more pronounced posterior channel in A. aenigma. Similarities to other species of Attiliosa, however, even to the early fossil taxa, are generic only. Attiliosa aenig- ma differs from the undescribed early Oligocene species from France in having a less angulate and sloped body whorl, a broader parietal shield, heavier spiral ornamen- tation, and a stronger posterior channel. Aftiliosa aenigma differs from the next earliest New World species, Attiliosa gretae Vokes, 1999, of the late early Miocene of Florida, in having a less angulate body whorl, a broader parietal shield, heavier spiral ornamentation, spiral cords of equal rather than unequal strength, a weaker anal channel, and a less recurved siphonal canal. The new species superficially resembles Panamurex rutschi Vokes, 1992 (Vokes, 1992: pl. 11, figs. 1-4) from the Pliocene Punta Gavilan Formation of Venezuela, par- ticularly in the morphology of the axial ribs, apertural lirae, and columellar nodules; however, P. rutschi differs in lacking the prominent anal channel and in having thicker, unpaired, and more widely spaced cords on the body whorl. Older species of Panamurex, particularly the Paleogene and early Neogene species, all have open spines on the body whorl and siphonal canal, and thus are very different from A. aenigma, which lacks spines altogether. The paired condition of the spiral cords in A. aenigma and A. bozzettii is noteworthy because the occurrence of similar spiral ornamentation in a number of species of Tak- ia (see above), including one of its geologically oldest spe- cies, Dermomurex (Takia) cookei MacNeil MS in Vokes, 1975, may indicate a closer phylogenetic relationship be- tween Afttiliosa and Takia than previously recognized. Un- til now, Attiliosa has been compared only to Panamurex or Calotrophon (Vokes, 1971, 1976, 1992, 1999). Detailed studies of the ontogeny of this character and cladistic methods are necessary to determine whether the paired condition is homologous in these different groups. We draw attention to this condition primarily because it has been ignored in past species descriptions and systematic reviews in the literature. A second fossil muricid (Figure 4) collected from Ter- ramar O01 could be referable to A. aenigma because of its nearly identical shell shape, size, and paired spiral cords. However, the axial ribs of this second specimen are nar- rower, and the columellar nodules are more prominent than in the holotype of A. aenigma. Additional material is needed to determine whether this specimen should be included in A. aenigma or whether it represents yet an- other undescribed species. The discovery of A. aenigma has significance for our understanding of the biogeographic history of the genus. Although Vokes (1989, 1992, 1999) proposed that the genus originated in the Old World during the Paleogene and migrated westward in post-Paleogene times, the latest Eocene/earliest Oligocene age of A. aenigma and its oc- currence in the New World questions this interpretation. Although age resolution of the European material and sampling resolution of the Paleogene fossil record are too Page 308 Figure 4. Afttiliosa sp. ct. A. aenigma Herbert & Portell. UF 104450; height 19.0 mm, maximum diameter 11.3 mm. Locality: Terramar 01 (POO17), Suwannee Limestone, Polk County, Flor- ida. a. Apertural view. b. Abapertural view. poor to determine when and where Aftiliosa first evolved, the timing and geographic position of the new species indicates, at the very least, that diversification and geo- graphic range expansion in Afttiliosa were occurring much earlier than previously thought. Future studies should concentrate on refining the systematics of Paleogene Mur- icidae from the Old World. Are there additional unde- scribed or “‘lost”’ taxa referable to Attiliosa and/or closely related groups, and, if so, what do they tell us about char- acter evolution and biogeographic patterns within the Muricinae? Acknowledgments. Rick Carter, Frank Garcia, Gary Morgan, Craig Oyen, Kevin Schindler, and Thomas Stemann assisted R.W.P. in collecting or acquiring specimens and/or bulk matrix from Terramar 01. Partial funding of fieldwork was provided by the Florida Museum of Natural History’s McGinty Endowment. Geerat Vermeij and Roland Houart provided helpful discussions of muricid systematics and biogeography. This is University of Florida Contribution to Paleobiology number 518. LITERATURE CITED BERGGREN, W. A., D. V. KENT, J. J. FLYNN & J. A. VAN Cou- VERING. 1985. Cenozoic geochronology. Geological Society of America Bulletin 96:1407—1418. The Veliger, Vol. 45, No. 4 BERGGREN, W. A., D. V. KENT, C. C. SWISHER, Il, M.-P. AUBRY & D. V. Kent. 1995. A revised Cenozoic geochronology and chronostratigraphy. Pp. 129-212 in W. A. Berggren (ed.), Geochronology, Time Scales and Global Stratigraphic Cor- relation. SEPM Special Publication 54. BREWSTER-WINGARD, G. L., T. M. Scott, L. E. Epwarps, S. D. WEEDMAN & K. R. Simmons. 1997. Reinterpretation of the peninsular Florida Oligocene: An integrated stratigraphic ap- proach. Sedimentary Geology 108:207-228. BRYAN, J. R. 1991. Stratigraphic and paleontologic studies of Paleocene and Oligocene carbonate facies of the eastern coastal plain. Doctoral Dissertation, The University of Ten- nessee. ix + 324 pp. Cooke, C. W. 1945. Geology of Florida. Florida Geological Sur- vey Bulletin 29:1—339. Cooke, C. W. & W. C. MANSFIELD. 1936. Suwannee Limestone of Florida (abstract). Geological Society of America Pro- ceedings for 1935. Pp. 71-72. HUDDLESTUN, P. FE 1993. A revision of the lithostratigraphic units of the Coastal Plain of Georgia. The Oligocene. Georgia Geologic Survey Bulletin 105. ix + 152 pp. Jones, D. S., P. A. MUELLER, D. A. HODELL & L. A. STANLEY. 1993. ®7Sr/*°Sr geochronology of Oligocene and Miocene marine strata in Florida. Pp. 15—26 in V. A. Zullo, W. B. Harris, T. M. Scott & R. W. Portell (eds.), The Neogene of Florida and Adjacent Regions. Proceedings of the Third Bald Head Island Conference on Coastal Plains Geology. Florida Geological Survey Special Publication 37. MANSFIELD, W. C. 1937. Mollusks of the Tampa and Suwannee limestones of Florida. Florida Geological Survey Bulletin 15:7-334. MANSFIELD, W. C. 1939. Note on unreported Oligocene in Citrus County, Florida. Journal of the Washington Academy of Sci- ences 29(2):45—46. Petucnu, E. J. 1997. A new gastropod fauna from an Oligocene back-reef lagoonal environment in west central Florida. The Nautilus 110(4):122-138. RANDAZZO, A. FE 1972. Petrography of the Suwannee Limestone. Florida Geological Survey Bulletin 54 (part 2). 13 pp. Vokes, E. H. 1971. The geologic history of the Muricinae and the Ocenebrinae. The Echo 4:37—54. VoKES, E. H. 1975. Cenozoic Muricidae of the western Atlantic region, pt. 6—Aspella and Dermomurex. Tulane Studies in Geology and Paleontology 11(3):121—162. VOKES, E. H. 1976. Cenozoic Muricidae of the western Atlantic region, pt. 7—Calotrophon and Attiliosa. Tulane Studies in Geology and Paleontology 12(3):101—132. VoKES, E. H. 1988. Muricidae (Mollusca: Gastropoda) of the Esmeraldas beds, northwestern Ecuador. Tulane Studies in Geology and Paleontology 21(1):1—50. VoKEs, E. H. 1989. Neogene paleontology in the northern Do- minican Republic. 8. The Family Muricidae (Mollusca: Gas- tropoda). Bulletins of American Paleontology 97(332):5—94. VoKEs, E. H. 1992. Cenozoic Muricidae of the western Atlantic region, pt. 9—Pterynotus, Poirieria, Aspella, Dermomurex, Calotrophon, Acantholabia, and Attiliosa; additions and cor- rections. Tulane Studies in Geology and Paleontology 25(1— 3):1-108. VoKES, E. H. 1999. Another look at the muricine genus Aftiliosa. The Veliger 42(4):289-305. Vokes, E. H. & A. D’ArtTILio. 1982. Review of the muricid genus Attiliosa. The Veliger 25(1):67—71. The Veliger 45(4):309—315 (October 1, 2002) THE VELIGER © CMS, Inc., 2002 Latitudinal Gradients in Body Size and Maturation of Berryteuthis anonychus (Cephalopoda: Gonatidae) in the Northeast Pacific JOHN R. BOWER', JAMES M. MURPHY? anp YASUKO SATO! "Faculty of Fisheries, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041-8611, Japan *Auke Bay Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, 11305 Glacier Highway, Juneau, Alaska 99801-8626, USA Abstract. Trends in body size and maturation with latitude of the gonatid squid Berryteuthis anonychus in the northeast Pacific are described. Squid were collected during May 1999 at seven stations along 145° and 165°W between 39° and 49°N. Mantle lengths ranged from 10.3 to 102.2 mm and increased significantly in both sexes from south to north. Females were both larger and more numerous than males at the northern stations. Both sexes showed a clear pattern of increasing maturity from south to north, and at each station, males were generally in a more advanced stage of maturity than females. Most mature males occurred at the northernmost stations. No mature females were collected. Our data suggest that B. anonychus migrates northward in the northeast Pacific during spring, with males maturing at a smaller size than females. INTRODUCTION Most studies of squid migration have been conducted on commercially important species that occur relatively near shore. Some of these species, such as Todarodes pacificus pacificus (Steenstrup, 1880), Dosidicus gigas (d’ Orbigny, 1835), and Illex illecebrosus (Lesueur, 1821), have been shown to migrate over long distances (> 1500 km) be- tween low-latitude spawning grounds and high-latitude feeding grounds (Hanlon & Messenger, 1996). Few stud- ies, however, have examined the migration patterns of more oceanic species. Berryteuthis anonychus Pearcy & Voss, 1963, is a small (mantle length to 150 mm), oceanic squid distrib- uted mainly in the northeast Pacific (Roper et al., 1984). It is a major prey for salmonids (Pearcy et al., 1988), Pacific pomfret (Brama japonica Hilgendorf, 1878; Pear- cy et al., 1993), and neon flying squid (Ommastrephes bartramii (Lesueur, 1821); Pearcy, 1991). Despite its im- portance in the food web of the subarctic North Pacific, little is known about its life history. In the present study, inferences are made on the migration and spawning of B. anonychus in the northeast Pacific based on trends in body size and maturation with latitude. MATERIALS anD METHODS Berryteuthis anonychus was collected as by-catch during a United States National Marine Fisheries Service survey of salmon in the northeast Pacific (Carlson et al., 1999). Sam- ples were collected during 6 to 17 May 1999 at seven Please address all correspondence to J. R. Bower; e-mail: akai- ka @fish.hokudai.ac.jp stations along 145° and 165°W between 39°01’ and 49°03'N (Figure 1). Sampling was conducted from just be- fore dawn to just after dusk. Both longitudinal transects were sampled in different directions (145°W—south to north; 165°W—north to south), and there was no diel pat- tern to the times at which stations were occupied, thus eliminating the possibility that any trends in body size and maturation with latitude seen in the data might have been due to sampling bias. At each station, a midwater trawl modified to fish at the surface was towed for | hour. The trawl was 198 m long with hexagonal mesh in wings and body, and a 1.2 cm mesh liner was used in the codend. Trawling speeds were 7-9 km hr', and the average net dimensions while fishing were 16 m vertical spread and 45 m horizontal spread. Subsamples of the total catches were taken at the two stations (#11 and #31) where more than 400 squids were collected. A total of 359 B. anony- chus specimens, including 195 males and 164 females, were examined in the following analyses. Specimens were sexed, and the dorsal mantle length of each was measured. A modified version of the maturity scales described by Lipinski & Underhill (1995) was used for maturity analysis (Table 1). The buccal membrane and inner mantle wall of each female were examined for the presence of discharged spermatophores or spermatangia (sperm vesicles) to deter- mine if any had mated before collection. The relationship between latitude and mantle length was evaluated using standard regression analysis, and the significance of the population regression was tested using analysis of variance (Zar, 1996:338—343). Normality of the size-frequency distribution at each station was tested using normal quantile plots (Sokal & Rohlf, 1995:118— 122). Male and female mantle sizes were compared at Page 310 The Veliger, Vol. 45, No. 4 65 60 55 50 45 AO @21 35 | 180 170 160 150 @ 31 @ 29 e 120 140. 130 Figure 1. Map of the Northeast Pacific showing sampling stations where Berryteuthis anonychus was collected and the long-term mean circulation (adapted from Musgrave et al., 1992). Station numbers correspond to those of Carlson et al. (1999). each station using the Mann-Whitney test. The relation- ship between latitude and the proportion of females in the catch was evaluated using Chi-square analysis (Zar, 1996: 562-565); the two southernmost stations, where more than 20% of the samples could not be sexed, were ex- cluded from this analysis. The relationship between ma- turity stage (dependent variable) and latitude (indepen- dent variable) was examined using polytomous logistic regression. Significance in all tests was accepted at the P = 0.05 level. RESULTS Size Mantle lengths (ML) ranged from 10.3 to 102.2 mm and increased significantly in both sexes from south to north (Figure 2, Table 2). Station #22 was exceptional in having a wide size range (10.3—75.7 mm ML), including eight specimens larger than 64 mm ML. Size-frequency data are normally distributed at all other stations except #11, where data are negatively skewed due to differences in size and abundance of males and females. Sex Females were both larger and more numerous than males at the northern stations. At each station north of 42°00'N, male and female sizes differed significantly. This size difference was most distinct at Station 11, where the mean female size was 14 mm larger than that of males. The proportion of females in the catches in- creased from south to north (Table 2) and followed a sig- nificant linear trend. No females had discharged sper- matophores or spermatangia present in the buccal mem- brane or inner mantle wall, suggesting that none had mat- ed before collection. Page 311 J. R. Bower et al., 2002 uleulal S330 sok sok MO] LO]TQISIA 9 < ON ‘onbedo ss3a Auvul ure}Uuo0S ou Auvul WO ‘9 qISIA 9 < JON ‘anbedo S339 Moj B UIe]UOS ou MJB WO ‘9[qISIA 9 < JON ‘onbedo $3359 OU UIe} 9 < TON ‘anbedo ou ou -UOD Ld] QISTA pue posiejuo 9 > TON ‘onbedo ou ou Q[QISIA JOU Jo quoredsur.n 9 > ION "Ju9 ou ou QIGISIA jou =—- -1ed suv) pue [[euts prosey = sayA900 s1OnplAO spurys Jospue — aanjyeul [eIUSWUIepIN uruy uIe}UOS apury, = SoLleag anbedo onbedo onbedo onbedo onbedo JUDON[SUBT] AI®AQ uondiiosap a8v}s a[euld] JIQISIA o1n} -on.ns SysniyM JIQISIA ony -onays SysniyM SIGISIA o1n} -ons SysoIyM 319 -ISIA JOU 91n} -onays SysoryM 919 -ISIA JOU 9.10} -onas SysoiyM quoredsue.y sysay, sok quasoid Moy SI< sod poyord ou juasoid A|asuap Gl< sok ou 0) T= SIl< sok ou 0 0 cI-S sok ou (0) 0 Cs SoA ou 0 (0) Cs ou prooey stud SN US I'd S[QISTIA Jo/pue ur$ OS ur) jo syed apuryyy ajyeivdas uondriosap o5¥}s a[vyy *xoTduioo quads TA amnieyy A BuLInjeyy AT Aioyeredoig [I] ainyewUy Tf otUsAne | a8e1S s0ydojeunttads ‘Dg ‘soroydoyeunsads *§ ‘OOTX TIW/T1d = Xepul yysue] stuad ‘[qJq :(stuad ay} Jo pus (4oLIa}Uv) [eISIP ay) 07 xa~duIOd SIOYdoyeuLIads oy) Jo ed JSOULIOLIOIUL JY} WOIJ VoURISIP) YISUs] Studd ‘Tq ‘JapuRdUT [RONPIAO ‘JIC {puL]s [eONPIAO ‘NOC ‘ovs ,SUIPYPOON ‘SN ‘OOTXTW/UISU2e] ON = xopul purys [eJUoWIepIU ‘JON :puvys [eJusWepiu ‘ON ‘yIsus] opueU “TY “(S66 [[yJepuy 2: Pysurdry wos paydepe) snyotuoun siyjnajKusag 10} pasn syeos Ayanyepy T 919eL The Veliger, Vol. 45, No. 4 165°W Frequency 1 2 3. 4 5 Crna 8 10) Mantle length (cm) Figure 2, Frequency distributions for mantle size of Berryteuthis anonychus collected in the northeast Pacific along 145° and 165°W. Maturity Both sexes showed a clear pattern of increasing ma- turity from south to north (Figure 3), and the relationship between maturity stage and latitude was significant. At each station, males were generally in a more advanced maturity stage than females. Mature (stage V) males oc- curred at four stations between 40°15’ and 49°O1'N and Table 2 Median mantle length (ML) and % of females in the catch of Berryteuthis anonychus at each station. Latitude Longitude Median ML (N) (W) Station # (mm) Female % 49°01’ 165° 1] 95.7 77 47°02’ 145° 37 92.2 63 42°07’ 165° 20 69.6 38 41°02’ 145° 3] 46.5 42 40°55’ 165° 21 39.3 39 40°15’ 165° 22 38.1 39°04’ 145° 29 26.8 ranged in size from 64.1 to 94.8 mm ML; 71% were collected at the two northernmost stations. The seven ma- ture males collected at and south of 41°02'N differed sig- nificantly in size from those at the two northernmost sta- tions (Mann-Whitney test, P < 0.001). Of males larger than 75.8 mm ML, 94% were mature. Females ranged in size from 23.3 to 102.2 mm ML, but none were mature. Of the most advanced female maturity stage collected (stage IIL), 89% were collected at the two northernmost stations. The five stage III females collected at and south of 42°07'N differed significantly in size from those at the two northernmost stations (Mann-Whitney test, P < 0.001). Station #22 was again exceptional in being the only southern station where advanced maturity stages of both sexes were collected. DISCUSSION Berryteuthis anonychus collected during spring in the northeast Pacific increased in size and maturity from south to north. Didenko (1990, in an abstract from the 5th All-USSR Conference on Commercial Invertebrates in 1990) reported similar trends in size and maturity with J. R. Bower et al., 2002 Page 313 165°W BB temale V7, male “> 145°W >< LS 400- 100- So 42-07N 47-02N Cc 50 Sta. 20 50 _ Sta. 37 S n(m) = 64 n(m) =14 a n(f)=45 n(f)=19 ab) (0) = (0) A — a 100- 100— S 40-55N Hee 41-02N = Sta. 21 2 Sta. 31 = 50— n(m) = 19 50- n(m) =41 om ‘5 n(f)=14 n(f)=27 100- 100-— 40-15N 39-04N n(m) =23 n(f)=27 Maturity stage Figure 3. Relative frequency distributions for maturity stage of Berryteuthis anonychus collected in the northeast Pacific along 145° and 165°W. latitude in this area during spring and summer. In the absence of known northward currents in this area, the simplest explanation for these patterns is that B. anony- chus actively migrates northward during spring and sum- mer. Ommastrephes bartramii, another pelagic squid distrib- uted widely in the North Pacific (Clarke, 1966), shows a similar trend of increasing size with latitude as it migrates northward during summer and fall. It hatches in subtrop- ical waters, migrates to feeding grounds north of 41°N, then returns south of 32°N to spawn (Murata & Naka- mura, 1998). As it migrates northward along 165°W, modal mantle lengths increase from 15 cm near 37°N to 40 cm near 46°N (Murata & Hayase, 1993), which is a mean increase in mantle length of about 19% per degree latitude. Berryteuthis anonychus modal mantle lengths in the present study increased from about 3 cm near 39°N to about 10 cm near 49°N, for a similar mean increase in mantle length of about 23% per degree latitude. The sizes of Berryteuthis anonychus found in predator stomachs collected in the Subarctic Current in the north- east Pacific during summer roughly correspond with the relation between body size and latitude seen in the present data. Pacific pomfret (Brama japonica) at 49-52°N prey heavily on > 70-80 mm ML squid (Pearcy et al., 1993), and salmonids at 45°30’-51°N prey heavily on 80-100 mm ML squid (Pearcy et al., 1988). In the Ridge Domain and Alaska Stream north of the Subarctic Current, small (< 60 mm ML) Gonatus spp. squids replace the larger B. anonychus as the main cephalopod prey of both Pacific pomfret and salmonids (Pearcy et al., 1988; Pearcy et al., 1993), suggesting that it becomes more difficult to prey on B. anonychus as it increases in size. Males matured at a smaller size than females. These data are consistent with those of other gonatids, including Berryteuthis magister magister (Berry, 1913), Gonatopsis borealis Sasaki, 1923, and Gonatus onyx Young, 1972 (Arkhipkin et al., 1996; Nesis, 1997). The occurrence of small maturing specimens south of 41°N suggests that early maturing forms may occur in southern waters. Ear- ly- and late-maturing groups have been reported in other pelagic squids, including G. borealis, and the ommastre- phids Sthenoteuthis pteropus (Steenstrup, 1855), S. oual- aniensis (Lesson, 1830), and Dosidicus gigas (Nesis, 1997; Masuda et al., 1998). Both sexes were of similar size and abundance at southern stations, but females became larger and more numerous than males at the northern stations. Differential growth of the sexes is common in cephalopods as they approach maturity (Forsythe & Van Heukelem, 1987), Page 314 with females growing larger than males in many oceanic squids, including Ommastrephes bartramii (Yatsu et al., 1998) and Berryteuthis magister magister (Natsukari et al., 1993). Off northeastern Japan, the sex ratio in catches of O. bartramii at the northern feeding grounds (42— 44°N) is nearly even, but the proportion of females in- creases as they approach the southern spawning grounds (Murata & Ishii, 1977). The spawning habitat of Berryteuthis anonychus is un- known, but two possible spawning scenarios can be sur- mised based on the present results. The first is that, like Ommastrephes bartramii, after feeding and growing in northern waters, B. anonychus returns to spawn south of 39°N, where the smallest specimens were collected in the present study. Such a pattern is consistent with the “‘one- return journey” migration pattern between low-latitude spawning grounds and high-latitude feeding grounds commonly seen in migrating pelagic squids, such as Dos- idicus gigas (Nesis, 1983), O. bartramii (Murata & Nak- amura, 1998). and Todarodes pacificus pacificus (Oku- tani, 1983)). A second, and more intriguing, scenario is that the main spawning grounds occur in northern waters. Berryteuthis anonychus paralarvae (ML < 10 mm) occur during summer in and near the Alaska Stream (Kubodera & Jefferts, 1984: J. R. Bower, unpublished data), indi- cating that hatching indeed occurs in the northern Gulf of Alaska. Berryteuthis anonychus may spawn near the seafloor along the continental slope as its congener B. magister magister does (Nesis, 1997). A northern-spawning-ground scenario would require southward currents to transport egg masses and paralar- vae to at least 39°N, where the smallest specimens were collected in the present study. Planktonic larvae of En- teroctopus dofleini (Wiilker, 1910) that hatch in coastal waters along the Aleutian Islands occur along 180° lon- gitude as far south as 45°N, 700 km south of the islands (Kubodera, 1991). Darnitsky et al. (1984) described the southerly movement of water from the Alaskan Stream along 170°E as far south as 40°N and suggested that it plays a role in transport of plankton from northern waters to the southern Emperor-Northern Hawaiian Ridge sea- mounts. These observations suggest that there are cur- rents in this area that could transport Berryteuthis anon- ychus eggs and paralarvae spawned near the Aleutian Is- lands southward. Clearly more data are needed, particularly collected over wide geographical and temporal scales, before de- finitive conclusions can be drawn on the complete migra- tory behavior of Berryteuthis anonychus in the northeast Pacific. The present study provides the first step in trying to understand the life history of this little studied, yet ecologically important, squid. Acknowledgments. We thank the late H. Richard Carlson for providing the first author with squids collected during the May 1999 NMFS salmon survey aboard the F/V Great Pacific. We also thank Kir Nesis, Michael Vecchione, and Richard Young for The Veliger, Vol. 45, No. 4 reviewing the manuscript, Marek Lipinski for his advice on con- structing maturity scales, Chingis Nigmatullin for translating a Russian abstract, Bryan Manly and Bradford Hawkins for their advice on regression analysis, and Kubodera-senpai for confirm- ing the identification of specimens. LIERAGURE CiteD ARKHIPKIN, A. I., V. A. Bizikov, V. V. KRYLov & K. N. NEsIS. 1996. Distribution, stock structure, and growth of the squid Berryteuthis magister (Berry, 1913) (Cephalopoda, Gonati- dae) during summer and fall in the western Bering Sea. Fish- ery Bulletin 94:1—30. Carson, H. R., J. M. MurpHy, C. M. KoNDZELA, K. W. MYERS & T. Nomura. 1999. Survey of salmon in the northeastern Pacific Ocean, May 1999. North Pacific Anadromous Fish Commission, Document No. 450, 37 pp. CLARKE, M. R. 1966. A review of the systematics and ecology of oceanic squids. Advances in Marine Biology 4:91—300. DarnitTsky, V. B., V. L. BOLDYREV & A. E VoLkov. 1984. En- vironmental conditions and some ecological characteristics of fishes from the central North Pacific seamounts. Pp. 64— 77 in P. A. Moiseev (ed.), Proceedings, Conditions of For- mation of Commercial Fish Concentrations. Ministry of Fisheries of the U.S.S.R. All-Union Research Institute of Marine Fisheries and Oceanography VNIRO. [Translated from Russian by W. G. Van Campen for the Southwest Fish- eries Center Honolulu Laboratory, National Marine Fisheries Service, NOAA, Honolulu Hawaii, 96922-2396, Translation No. 114] FORSYTHE, J. W. & W. F VAN HEUKELEM. 1987. Growth. Pp. 135— 156 in P. R. Boyle (ed.), Cephalopod Life Cycles, Vol. II: Comparative Reviews. Academic Press: London. HANLON, R. T. & J. B. MESSENGER. 1996. Cephalopod Behaviour. Cambridge University Press: Cambridge. 232 pp. KUBODERA, T. 1991. Distribution and abundance of the early life stages of octopus, Octopus dofleini Wiilker, 1910 in the North Pacific. Bulletin of Marine Science 49:235—243. KUBODERA, T. & K. JEFFERTS. 1984. Distribution and abundance of the early life stages of squid, primarily Gonatidae (Ceph- alopoda, Oegopsida), in the Northern North Pacific (Part 2). Bulletin of the National Science Museum, Series A (Zool- ogy) 10:165-193. Lipnskt, M. R. & L. G. UNDERHILL. 1995. Sexual maturation in squid: quantum or continuum? South African Journal of Ma- rine Science 15:207—223. Masupa, S., Y. YOKAWA, A. YaTsU & S. KAWAHARA. 1998. Growth and population structure of Dosidicus gigas in the southeastern Pacific. Pp. 107-118 in T. Okutani (ed.), Con- tributed Papers to International Symposium on Large Pelagic Squids. Japan Marine Fishery Resources Research Center: Tokyo. Murata, M. & S. Hayase. 1993. Life history and biological information on flying squid (Ommastrephes bartramii) in the North Pacific Ocean. International North Pacific Fisheries Commission Bulletin 53:147—182. Murata, M. & M. IsHu. 1977. Some information on the ecology of the oceanic squid, Ommastrephes bartrami (Lesueur) and Onychoteuthis borealijaponicus Okada, in the Pacific Ocean off northeastern Japan. Bulletin of the Hokkaido Regional Fisheries Research Laboratory 42:1—23. [in Japanese with English abstract] Murata, M. & Y. NAKAMURA. 1998. Seasonal migration and diel vertical migration of the neon flying squid, Ommastrephes bartramii, in the North Pacific. Pp. 13-30 in T. Okutani J. R. Bower et al., 2002 Page 315 (ed.), Contributed Papers to International Symposium on Large Pelagic Squids. Japan Marine Fishery Resources Re- search Center: Tokyo. Muscrave, D. L., T. J. WEINGARTNER & T. C. Royer. 1992. Cir- culation and hydrography in the northwestern Gulf of Alas- ka. Deep-Sea Research Part A. 39:1499—1519. NATSUKARI, Y., H. Mukal, S. NAKAHAMA & T. KUBODERA. 1993. Age and growth estimation of a gonatid squid, Berryteuthis magister, based on statolith microstructure (Cephalopoda: Gonatidae). Pp. 351-364 in T. Okutani, R. K. O’Dor & T. Kubodera (eds.), Recent Advances in Cephalopod Fisheries Biology. Tokai University Press: Tokyo. Nesis, K. N. 1983. Dosidicus gigas. Pp. 215-231 in P. R. Boyle (ed.), Cephalopod Life Cycles, Vol. I: Species Accounts. Ac- ademic Press: London. Nesis, K. N. 1997. 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Prentice-Hall: Upper Saddle River, New Jersey. 662 pp. THE VELVIGER © CMS, Inc., 2002 The Veliger 45(4):316-330 (October 1, 2002) Ultrastructure of Muscle-Shell Attachment in Nautilus pompilius Linnaeus (Mollusca: Cephalopoda) SHINJI ISAJI Natural History Museum and Institute, Chiba, 955-2, Aoba-cho, Chuo-ku, Chiba, 260-8682, Japan TOMOKI KASE National Science Museum, Tokyo, 3-23-1, Hyakunincho, Shinjuku-ku, Tokyo, 169-0073, Japan KAZUSHIGE TANABE Department of Earth and Planetary Science, University of Tokyo, 7-3-1, Hongo, Tokyo, 113-0033, Japan AND KIMIO UCHIYAMA Toba Aquarium, Toba City, Mie, 517-0011, Japan Abstract. The ultrastructure of the muscle-shell attachment in the embryo and adult specimens of Nautilus pompilius Linnaeus, 1758, was investigated by optical and transmission electron microscopy. In adult specimens, myoadhesive mantle epithelial cells at the attachment site of the retractor muscle are high columnar and characterized by elongate microvilli having undulate cytoplasmic membranes, numerous bundles of fibrils, and interconnection with neighboring cells by means of interdigitation. The inner shell wall of the body chamber at the attachment site is covered by a thick (approx. 80 wm thick in adult animals) semi-transparent membrane. The tips of the microvilli are very thin and interwined with each other, and do not insert into the inner surface of the semi-transparent membranes. Similar features are also observed in the myoadhesive cells at both the attachment site of the retractor muscle and the initial portion of the siphuncular cord of the embryo. The myoadhesive epithelium-semi-transparent membrane junction of N. pompilius seems to be physically weak against tensile stress caused by muscle movement. The peculiar mode of muscle-shell attachment in Nautilus appears to have developed as a result of adaptation to a nektonic mode of life and mode of shell growth followed by a chamber formation cycle. INTRODUCTION attachment may also provide an important information source to improve our understanding of the paleobiology of extinct mollusks. Ultrastructural features of the muscle-shell attachment have been investigated in bivalves (Nakahara & Bevelan- der, 1970), gastropods (Tompa & Watabe, 1976), mono- (myoadhesive cells) intervene between the muscle fibers econ toes (as 7prunar eacieitoe 1-2 /7))) Eel See and the shell (e.g., Hubendick, 1958; Nakahara & Beve- phopods | (hime. ae ste eee lander, 1970; Tompa & Watabe, 1976). On the inner shell works, it was realized that the myoadhesive cells are dif- surface, the attached area of the myoadhesive cells is dis- ferentiated into cuboidal, fiber-rich cells having short mi- tinguished with a unique shell structure from the non- crovilli, which are basically common among different Calcareous hard exoskeletons of mollusks play important roles in protecting soft parts from ambient environments and providing a solid base for muscle attachment. In all mollusks hitherto examined histologically, a collagenous intercellular matrix and specialized epithelial cells attached area by the presence of variably depressed scars, VERN which correspond to the exposed surface of the myos- Nautilus is the sole living genus of the ectocochleate tracum. Such attachment scars provide a reliable key to cephalopods. Various attachment scars impressed on the reconstructing the muscle system of fossil mollusks. inner shell surface are the only direct evidence of the Therefore, many biologists and paleontologists have fo- shape and location of the attachment of the soft body to cused on the attachment scars in molluscan shells from the shell. Previous authors have focused mainly on the the viewpoints of taxonomy, functional morphology, and shape and location of the attachment scars in the shell of physiology. Ultrastructural features of the muscle-shell Nautilus (e.g., Grégoire, 1962; Tanabe et al., 1991; Mut- S. Isaji et al., 2002 Page 317 10mm Figure 1. Shape of the attachment scar and the corresponding muscle termination in Nautilus (lateral views). A. Attachment scar on the left side of the body chamber. B. Mirror image of the muscle termination of the left side of the body. Key: abs, anterior band scar; mmb, mantle myoadhesive band; Is, large scar; pns, posterior narrow scar; rm, retractor muscle; smb, septal myoadhesive band. vei et al., 1993; Doguzhaeva & Mutvei, 1996; Mutvei & Doguzhaeva, 1997), but the details of the muscle-shell attachment have been little investigated except for light microscopic observations carried out by Bandel & Spaeth (1983). Bandel & Spaeth (1983) reported that the high columnar myoadhesive epithelial cells have elongate mi- crovilli, whose structure differs from those in the other molluscan groups. Such differences may have specific functional significance; yet no observations by means of transmission electron microscopy have been done on the muscle-shell attachment. The purpose of this paper is to describe the ultrastruc- tural features of muscle-shell attachment in Nautilus pom- pilius. It also discusses possible functional explanations of the attachment system of Nautilus in relation to the animals’ nektonic mode of life and their mode of growth involving the chamber formation cycle. MATERIALS and METHODS One adult (approx. 200 mm diameter) and one young adult (135 mm diameter) of Nautilus pompilius Linnaeus, Figure 2. Diagrammatic representation of a myoadhesive epithelial cell located at the attachment site of the retractor muscle of the adult animal of Nautilus pompilius. Key: bf, bundles of fibrils; bhd, basal hemidesmosome; bi, basal infolding; cz, collagenous zone; d, desmosome:; i, interdigitation; mv, microvilli; n, nucleus; sm, semi-transparent membrane. Page 318 1758, were collected off Tagnan, Panglao Island, Bohol, the Philippines, on 14 May 1996. One embryo came from an egg laid on 6 June 1997, at the Toba Aquarium by an adult animal, which was captured from off Taar area, southern Luzon Island, the Philippines. The embryo was taken from the egg capsule on 6 November 1997, after incubating 154 days at a mean temperature of 23°C. For observation of the shapes of attachment scars and the corresponding lateral termination of the attachment muscle, one young adult animal was examined. The an- imal was fixed with 10% formalin without decalcification. Subsequently, the shell was cut along the medial axis, and the soft tissue was carefully removed from the shell for observation under a binocular microscope. One adult and the embryo were examined by trans- mission electron microscopy (TEM). In the case of the adult specimen, the shell was carefully removed from the soft tissue without decalcification, and the mantle epithe- lium at the attachment site of the retractor muscle to the inner shell wall was sectioned into small pieces and fixed with 2% paraformaldehyde/2% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.5) for several days. The prepa- ration of the embryo was done in the following manner. After removing the yolk mass, the whole body of the embryo was fixed with 2% glutaraldehyde in 0.1 M cac- odylate buffer (pH 7.5) with 6% sucrose added for os- molarity for several days. It was subsequently decalcified with 4.13% EDTA buffered to pH 7.5, and the epithelial portion was sectioned into two pieces along the ventro- dorsal plane, one at the attachment site of the retractor muscle and the other at the mid-apical portion which at- tached to the inner shell wall. Pieces of soft tissue of the adult and embryonic specimens were subsequently washed in cacodylate buffer for 4 hours and post-fixed in 2% osmium tetroxide for 1.5 hours. After dehydration in an ethanol series, they were embedded in Epon 812 resin for the adult materials and in Spurr resin for the embry- onic ones. Ultra-thin sections were prepared for the tissue materials with a diamond knife using an LKB-Ultrotome. Sections of the adult specimens were stained with uranyl acetate and lead citrate. Those of the embryo specimens were stained with potassium permanganate and lead cit- rate to emphasize the contrast of electron density. These sections were examined and photographed with a Jeol JEM-1200EX II TEM. One-ym-thick sections were stained with toluidine blue for optical microscopy. Figure 3. The Veliger, Vol. 45, No. 4 Terminology used in this description is partly that used by Mutvei & Doguzhaeva (1997). RESULTS Shape of Attachment Scar and Muscle Termination The annular attachment scars occur on the lateral and dorsolateral sides of the inner wall of the body chamber in front of the last septum. Figure 1A shows the lateral view of one half of the annular attachment scars pre- served on the left inner side of the body chamber. The scar is divisible into anterior and posterior parts. The an- terior portion of the scar comprises an anterior band scar and a large scar (Figure 1A; abs + Is). The large scar is somewhat trapezoidal in shape showing anterior round and posterior slightly angular outlines. The posterior scar, in contrast, is expressed as a sharply impressed, very nar- row annular scar (Figure 1A; pns). The annular myoad- hesive epithelial regions that produce these scars encircle the body. Figure 1B shows the mirror image of the myoadhesive epithelial regions on the left side of the body. These regions compose the annular band of origin of the longitudinal mantle muscles (= mantle myoadhe- sive band: mmb), large lateral termination of the retractor muscle (rm), and a narrow annular band, along which the muscles from the septal portion of the body wall take their origin (= septal myoadhesive band: smb) in order from anterior to posterior side of the body. The attach- ment area of the retractor muscle is crescent-shaped and overlaps the mantle myoadhesive band at the anterior edge. The septal myoadhesive band (smb) is equal in shape to the corresponding attachment scars (pns). The anterior edge of the mantle myoadhesive band (mmb) also cor- responds to the anterior line of the anterior attachment scar (abs). In contrast, the posterior edge of the large scar (Is) is broader than the lateral termination of the retractor muscle (rm). This fact indicates that the myoadhesive ep- ithelial area is broader than the lateral termination of the attachment muscle. Ultrastructure of Muscle-Shell Attachment In Nautilus, the muscle fibers terminate in a collage- nous zone at the base of the myoadhesive epithelium. Light micrographs of the longitudinal sections of the myoadhesive epithelial regions of adult and em- bryonic animals of Nautilus pompilius. A, Retractor muscle attachment of the adult. B. Retractor muscle attachment of the embryo. Enlarged view at the ventral edge of attachment site (asterisk) is shown in Figure 7. C. Initial portion of the siphuncular cord of the embryo. Enlarged view at the ventral edge of attachment site (asterisk) is shown in Figure 9. Key: cz, collagenous zone; me, myoadhesive epithelium; rmf, retractor muscle fiber; ne, non- adhesive epithelium; nl, nacreous layer; p, periostracum; pl, prismatic layer; sm, semi-transparent membrane. Arrows indicate ventral direction. Scale bar = 100 wm. S. Isaji et al., 2002 Page 319 Page 320 The Veliger, Vol. 45, No. 4 Figure 4. TEM of the myoadhesive epithelial cells at the attachment site of the retractor muscle of the adult Nautilus pompilius. Key: bf, bundle of fibrils; cz, collagenous zone; i, interdigitation; n, nucleus; sd, secretory droplet; sm, semi-transparent membrane. Scale bar = 10 pm. This is basically the same as in other molluscan groups such as monoplacophorans (Haszprunar & Schaefer, 1997), gastropds (Tompa & Watabe, 1976), bivalves (Na- kahara & Bevelander, 1970), and scaphopods (Shimek & Steiner, 1997). However, Nautilus possesses characteristic features in the morphology of the myoadhesive cells and their apical junction to the extracellular sheet (semi-trans- parent membrane), which is directly attached to the inner wall of the body chamber. The ultrastructures of the myoadhesive cells are illustrated diagrammatically in Fig- ure 2. Adult Stage: Attachment Site of Retractor Muscle The myoadhesive epithelium at the attachment site of the retractor muscles is connected indirectly with the shell through the medium of the semi-transparent membrane (Figure 3A; sm), which has been variously termed con- chin layer, pseudo-tendon (Mutvei, 1957), membranous disc (Grégoire, 1962), and an organic (conchiolin) lamella (Mutvei & Doguzhaeva, 1997). Such a membrane attains about 80 ym in thickness and shows a banded structure parallel to the shell surface. It is very similar to the per- iostracum in electron density (Figures 4, 5). The myoadhesive cells (height approx. 45 wm, width 6-10 pm) are high columnar in shape. They have well developed microvilli (length > 10 fm) which occupy a fourth of the cell height (Figure 4). The basal portion of each microvillus (diameter 0.2—0.25 jzxm) is perpendicu- larly arranged to the apical surface of the cell. Its diam- eter gradually decreases distally, showing intertwist fac- ing to the inner surface of the semi-transparent membrane (Figure 5). The tips of the microvilli never insert into the membrane. The cytoplasmic membranes of the microvilli are remarkably undulated. Well developed bundles of fi- brils occur in the microvilli (Figure 5). The bundles of fibrils traverse the entire length of the Figure 5. TEM of the microvilli of myoadhesive epithelial cells at the attachment site of the retractor muscle of the adult Nautilus pompilius. Key: bf, bundle of fibrils; cm, cytoplasmic membrane of microvillus; sm, semi- transparent membrane; v, vesicle. Scale bar = 1 wm. Page 321 S. Isaji et al., 2002 Page 322 The Veliger, Vol. 45, No. 4 S. Isaji et al., 2002 cell (Figures 4, 6). They form very large bundles at the central and basal portions of the cell (Figure 6), and split up apically so as to send a bundle to each microvillus (Figures 5, 6A). The bundles of fibrils are basally con- nected by hemidesmosomes with the basal cytoplasmic membrane (Figure 6B). Electron densities of the cytoplasm of myoadhesive cells are remarkably variable throughout the epithelium (Figure 4). Numerous secretory droplets produced by electron-lucent epithelial cells are observed in apical and interstitial spaces of the microvilli (Figure 4). Electron- lucent vesicles are especially abundant in the apical por- tion of the electron-dense cell (Figure 5). Elongated elliptical nuclei are situated in the basal half of the cell (Figure 4). Their electron densities correspond with those of the cytoplasm. The electron-dense nuclei are more compressed than the electron-lucent nuclei. Each adhesive cell is interconnected to the adjacent cells by belt desmosomes, followed by well developed inter- digitations (Figures 4, 6A). Basal infoldings are also well developed in each adhesive cell (Figure 6B). Embryonic Stage: Attachment Site of Retractor Muscle The myoadhesive epithelial cells at the attachment site of the retractor muscles of the 154-day-old embryo mea- sure about 20 pm in height and 5-10 pm in width. At the ventral edge of the attachment area, the boundary be- tween the adhesive cells and the non-adhesive ones (height about 10 pm) is recognizable by the drastic change of cell height (Figures 3B, 7). In addition, the microvilli of the most ventrally situated myoadhesive cells are longer than those of the adjacent non-adhesive cells (Figure 7). Toward the dorsal portion of the attach- ment area, such microvilli gradually increase their length, and their tips become more slender. In association with this change of microvillous length, the cytoskeleton grad- ually increases, and the cytoplasmic membranes become undulated (Figure 8A). Dense bundles of fibrils are poorly developed as com- pared with those of the adult cells. As observed in the adult specimen, the bundles of fibrils split up apically so as to send a bundle to each microvillus (Figure 8A) and are basally connected by hemidesmosomes with the basal cytoplasmic membrane. Elliptical nuclei are situated in the center of the cell. Mitochondria are often concentrated in the upper half of the cell (Figure 8A). Electron density Page 323 of the cytoplasm within the myoadhesive epithelium is relatively more uniform in comparison with that of the adult, although there is some variation. Numerous characteristic projections are observed in the apical surface of the attachment epithelium (Figure 8A, B). Such projections gradually increase in number dorsally within the attachment area, whereas they are ab- sent in the cells near the ventral edge (Figure 7). Each projection is conical in shape, with a slender tip (diameter approx. 0.5 tm) and has numerous small vesicles (di- ameter 50—100 nm) and a few cytoskeletons (Figure 8A, B). Interdigitations in the interconnection among the ad- jacent cells are more poorly developed than those in the adult cells (Figure 8A). Basal infoldings are unclear. In the attachment site of the retractor muscle of the embryo, the inter- and intra-crystalline organic matrices appear to preserve the shape of the original shell struc- ture. The inner shell wall of the ventral edge of the at- tachment area is composed of a nacreous layer (= mnw in Tanabe & Uchiyama, 1997) (Figures 3B, 7). In going to the dorsal portion of the attachment area, a prismatic layer (= ipw in Tanabe & Uchiyama, 1997) appears un- derneath the nacreous layer (Figures 3B, 8B). In accor- dance with the deposition of the prismatic layer, the in- nermost shell wall is covered by an organic membrane, which shows a similar electron density to the periostrac- um (Figure 8B). This organic membrane appears to be the same as the semi-transparent membrane observed in the adult specimens. The boundary between the nacreous and prismatic lay- ers is clearly marked (Figures 3B, 8B). whereas the boundary between the prismatic layer and organic mem- brane is irregular because both layers are variable in thickness and in places interfinger with each other (Figure 8B). The wall of the organic membrane facing the apical free surface of the myoadhesive cell is smooth and dis- tinct (Figure 8B). Embryonic Stage: Initial Portion of Siphuncular Cord The myoadhesive cells at the ventral edge of the initial portion of siphuncular cord are about 20 pm in height and 5 wm in width (Figure 9A). A drastic change of cell height is also observable at the boundary between the non-adhesive and adhesive cells (Figures 3C, 9A). Characteristic features such as regional variation of the ultrastructure of the microvilli, projections, and interdig- Figure 6. TEMs of the apical and basal parts of the myoadhesive epithelial cells of the adult Nautilus pompilius. A. Bundles of fibrils splitting up so as to send a bundle to each microvillus. Each cell is tightly connected with neighboring cells by well developed interdigitations. B. Bundles of fibrils connected by hemidesmosomes with the basal cytoplasmic membrane which represents basal infoldings. Key: bf, bundles of fibrils: bhd, basal hemides- mosome; bi, basal infolding: cz, collagenous zone; d. desmosome: i, interdigitation: my, microvilli: n. nucleus. Scale bar = 2 pm. Page 324 The Veliger, Vol. 45, No. 4 Figure 7. TEM of the ventral edge of the attachment area of the myoadhesive epithelium at retractor muscle (asterisk in Figure 3B) showing drastic change of cell height between the ventrally situated non-adhesive cells and the dorsally situated adhesive ones. Key: bm, basal membrane; d, desmosome; my, microvilli; n, nucleus; nl, nacreous layer. Scale bar = 2 wm. S. Isaji et al., 2002 Page 325 Figure 8. TEMs of the apical portion of the myoadhesive cells at the retractor attachment site of embryo of Nautilus pompilius. A. Myoadhesive cells showing projections, elongate and undulate microvilli, and weakly developed interdigitation. B. Undissolved organic matrix of nacreous and prismatic layers. Prismatic layer is covered by organic membrane. Key: d, desmosome; i, interdigitation; mt, mitochondria; mv, microvilli; nl, nacreous layer; om, organic membrane; p, projection; pl, prismatic layer. Scale bar = 1 pm. The Veliger, Vol. 45, No. 4 Page 326 \ re ee peasy S. Isaji et al., 2002 Page 327 9 0 ac p 9 AOI Os Figure 10. TEM of non-adhesive epithelial cells located near the initial portion of the siphuncular cord of the embryo of Nautilus pompilius. Key: bm, basal membrane; n, nucleus; tw, terminal web. Scale bar = 10 pm. itation within the interconnected cells and the bundles of fibrils are similar to those of the cells at the attachment site of the retractor muscle of the embryo. Golgi bodies and centrioles are observed occasionally, especially in the upper part of the cells (Figure 9B). At the dorsal edge of the initial portion of the siphun- cular cord, the height of the adhesive cells is the same as that of the adjacent non-adhesive ones, whereas the mi- crovilli are not elongated and the projections do not occur in the non-adhesive cells. A few extracellular matrices are observed at the ventral edge of the myoadhesive epithe- lium (Figure 9A). It is not clear whether these matrices are of undissolved shell origin or represent an organic membrane facing the inner shell wall. Non-Adhesive Epithelium (Simple Mantle Epithelium) Non-adhesive epithelial cells are observed at three dif- ferent epithelial portions of the embryo: the area in front of the ventral edge of the retractor attachment site, and the adjacent sites of the ventral and dorsal edges of the initial portion of the siphuncular cord. These cells are shorter (height approx. 10 pm) than those of the adjacent adhesive cells (Figure 3B, C). The terminal webs are well developed at the apical portion (Figure 10). They do not exhibit specific features such as elongate microvilli with undulate cytoplasmic membrane, projection, interdigita- tion, and bundles of fibrils, all of which occur in the ad- hesive cells. DISCUSSION Ultrastructural Features of Muscle-Shell Attachment As already described by previous workers (e.g., Mut- vei, 1957; Grégoire, 1962) in Recent Nautilus, a thick semi-transparent membrane lines the inner surface of the shell wall of the body chamber in front of the last septum. Our TEM observations have revealed that the membrane at the attachment site of the retractor muscle in the em- bryo has an irregular surface, seemingly providing a firm attachment to the prismatic shell layer of the inner shell wall. Although we could not observe the ultrastructure of the shell-membrane junction in the adult specimens, the same relationship observed in the embryo may exist be- cause the texture of the inner surface of the shell wall just beneath the membrane exhibits ‘““swarming lenticular and spheroidal seed crystallites” (Grégoire, 1962, 1987: 472) and ‘‘vertically oriented acicular crystallites’? (Mut- vei & Doguzhaeva, 1997:48). In addition, such texture differs greatly from that of the membrane-free inner shell surface (Grégoire, 1962, 1987). Therefore, the surface texture of the attachment scars appears to be effective for a firm attachment of the shell to the membrane. Judging from the ultrastructure of the shell-membrane junction, the shape of the scar produced on the internal shell wall should correspond to the attachment area of the semi-transparent membrane, which appears to be secreted by the myoadhesive epithelium. Thus, the attachment area Figure 9. TEMs of the attachment site of the initial portion of the siphuncular cord in the embryo of Nautilus pompilius. A. Boundary between myoadhesive (right) and non-adhesive (left) cells at the ventral edge of the attachment area (asterisk in Figure 3C). B. Enlarged view of the right corner of Figure 9A, showing projections and elongate microvilli. Key: bm, basal membrane; c, centriole; d, desmosome; gb, Golgi body; mt, mitochondria; n, nucleus; om, organic membrane; p, projection. Scale bar = 5 pm. Page 328 of this membrane also should correspond to the myoad- hesive epithelial area. Curiously, the attachment area of the myoadhesive cells occurs beyond the posterior edge of the lateral termination of the retractor muscle (Figure 1). Such a situation has not been reported in other mol- lusks. This fact simply indicates that it is impossible to reconstruct the exact details of the shape of the lateral termination of the muscle based on the attachment scar, if other externally shelled cephalopods in the fossil record have a similar mode of shell-muscle attachment as is ob- served in N. pompilius. This study also revealed that the tips of elongate mi- crovilli do not insert into the membrance and have no specific features showing a firm connection with the membrane. Therefore, there may be a unique intercon- nection by means of an indirect process between the two. Dense slender microvilli that are intertwined with each other appear to form a distinct plane at the free surface. There might be little interstitial space between the micro- villous plane and the inner surface of the membrane. If the interstitial space of microvilli is filled with fluid, it might produce an adhesive property between the two planes. The myoadhesive cell in adult Nautilus has character- istic features such as a tightly packed high columnar shape, interconnection by well developed interdigitations, bundles of fibrils, and basal infoldings, suggesting that the epithelium has sufficient strength to resist the tension produced by muscle movement. Furthermore, the asso- ciation of interdigitations, basal infoldings, and elongate microvilli also suggests that the myoadhesive cells have an active property of ion transport which may be involved in the secretion of the semi-transparent membrane or some kind of fluid. These features are also observed but poorly developed in the myoadhesive cells of the embryo. This fact suggests that the development of myoadhesive cells occurs after hatching in relation to the increase of muscle movement for swimming and some kinds of lo- comotion, although differentiation of myoadhesive cells begins even at the relatively static embryonic stage. Cell projection is a unique feature in the myoadhesive cell of the embryo. It might gradually disappear with growth. Its functional significance is unknown. According to Mutvei & Doguzhaeva (1997), the inside surface of the adult shell aperture of N. pompilius is perforated by vertical canals, in which finger-shaped epithelial exten- sions from the mantle are presumably inserted. Mutvei & Doguzhaeva (1997) suggested that the mantle seems to be firmly attached to the apertural region of the shell. In the embryonic stage, however, the projections do not in- sert into the shell. Thus, it is not plausible that the pro- jections are homologous to each other. In summary, the myoadhesive cell appears to have a physically weak junction at the apical free surface with the semi-transparent membrane, but the epithelium itself is sufficiently strong to resist the tensile stress caused by The Veliger, Vol. 45, No. 4 muscle movement. The method for muscle attachment to the shell of Nautilus is unique as compared with those in other examined mollusks. According to Tompa & Watabe (1976), in gastropods, the myoadhesive cell (Tompa & Watabe’s tendon cell) is attached to the tendon sheath by means of hemidesmosomes at the tips of their very short microvilli, and the tendon sheath inserts fibers into the shell during calcification. The method for muscle attach- ment to the shell and the ultrastructure of myoadhesive epithelium observed in gastropods are the same as those in monoplacophorans (Haszprunar & Schaefer, 1997), scaphopods (Shimek & Steiner, 1997), and bivalves (e.g., Nakahara & Bevelander, 1970). Such a method of mus- cle-shell attachment seems to be physically stronger against some kinds of tension than is the case in Nautilus. Bandel & Spaeth (1983) pointed out the morphological similarities between the myoadhesive and siphuncular ep- ithelia of Nautilus on the basis of light microscopy. The siphuncular epithelium of Nautilus functions as pumping involved in emptying the cameral fluid from the air cham- bers into blood vessels (Denton & Gilpin-Brown, 1966; Greenwald et al., 1982). The siphuncular epithelial cells form an extensive system of basolateral cell infoldings (canaliculi) that are lined with mitochondria and give the cytoplasm a feathery appearance (Greenwald et al., 1982). However, the myoadhesive epithelium does not possess canaliculi, and the number of mitochondria in each cell is less than that in the siphuncular epithelium. In addition, the apical portion of the myoadhesive ep- ithelium of N. pompilius resembles the siphuncular epi- thelium of Sepia officinalis Linnaeus, 1758, in the pres- ence of elaborate microvilli underneath the organic sheet that closes the cuttlebone posteriorly (Wendling, 1987, cited in Budelmann et al., 1997:fig. 55). In both Nautilus and Sepia, the apical infoldings occur in the siphuncular epithelial cells, but they do not occur in the myoadhesive cells of Nautilus. Therefore, the ultrastructural similarities of the myoadhesive and siphuncular epithelial cells be- tween Nautilus and Sepia appear to have originated in the high activity of ion transport. Functional Aspects of Muscle-Shell Attachment As described above, the ultrastructure of the muscle- shell attachment in Nautilus is unique and differs from those of other mollusks. Interestingly, the ultrastructural characteristics observed in the muscle-shell attachment in the latter groups are essentially similar to those of the buccal muscle attachment to the beak in octopods and squids (Dilly & Nixon, 1976), the muscle attachment to the shell of articulated brachiopods (Stricker & Reed, 1985), and the peduncle muscle attachment to the cutic- ular flange in the opercular filament of polychaete anne- lids (Bubel, 1983). In polychaete annelids, for example, the elongate specialized microvilli of the myoadhesive cells penetrate the inner wall of the cuticular flange, sug- S. Isaji et al., 2002 gesting that an extremely tight connection occurs between the epithelium and cuticular flange. These examples sug- gest that a tight connection occurring at the muscle at- tachment to the hard exoskeleton is a common condition among different animals. Why does Nautilus develop such a curious muscle- shell attachment system? How is it effective in relation to the mode of life and ontogenetic growth? The nektonic mode of life in Nautilus may be a key to assuming these questions. Most other externally shelled mollusks are benthic. When benthic mollusks perform various actions such as valve opening and closing, or crawling on and burrowing into substratum, they bear their own weight on the muscular system. In such situations, the myoadhesive epithelium functions as tendon because it receives a large tensile stress caused by muscle movement. In other words, in benthic mollusks, a tight connection between the internal shell wall and the myoadhesive cells appears to be necessary to sustain the large tensile stress. On the contrary, Nautilus maintains neutral buoyancy in the wa- ter column by means of a chambered shell filled with low-pressure gas and small amounts of liquid. Therefore, the tensile stress bearing the myoadhesive cells may be relatively reduced in this animal. Another factor is the mode of mantle shifting through the inside of the body chamber during growth. In Nau- tilus, the formation of a new chamber is episodic. At the stage of a new chamber formation, the septal myoadhe- sive band is rapidly moved forward in the body chamber, where it reattaches to the internal shell wall (Ward & Chamberlain, 1983). It is suggested that a loose connec- tion between the epithelium and the semi-transparent membrane lining the inner wall of the body chamber may be effective for the alternating mode of peeling off and reattachment of the septal myoadhesive band. By con- trast, the shift of the attachment site for the retractor mus- cle corresponds to the apertural shell growth, which is constant throughout new chamber formation (Ward & Chamberlain, 1983). However, there are no structural dif- ferences between the retractor and septal myoadhesive cells based on light microscopic observations. Having a loose attachment of the epithelium to the shell might also be a favorable condition for moving of the myoadhesive cells because they appear to shift more than 30 centi- meters throughout ontogeny, whereas the expansion rate of the lateral termination of the muscle seems to be con- siderably smaller as compared with that of other mol- lusks. As pointed out above, the nektonic mode of life and the mode of shell growth in combination with the cham- ber formation cycle during ontogeny in Nautilus are unique among mollusks. Therefore, the muscle-shell at- tachment in Nautilus might have developed as a response to its own functional demands. If the mechanism of mus- cle-shell attachment in mollusks is highly constrained by mode of life and shell growth, a similar mechanism might Page 329 occur even in distantly related taxa. In fact, all mollusks hitherto examined excluding Nautilus, are sessile or mo- bile benthos. Thus, there is a possibility that nektonic and planktonic mollusks such as janthinid, pteropod, and het- eropod gastropods have a similar mechanism of muscle- shell attachment to that observed in Nautilus. Acknowledgments. We are grateful to Drs. Klaus Bandel (Uniy- ersitat Hamburg), Rudolf Schipp (Justus-Liebig-Universitat), and Neil Landman (American Museum of Natural History) for crit- ical review of the manuscript and for valuable comments. We also thank Dr. Yoshio Fukuda (Chiba Prefectural Institute of pub- lic Health) for helpful discussions. This work was partly sup- ported by a Grant-in-Aid from the Japanese Ministry of Educa- tion, Science and Sports (No. 09304049). This manuscript ben- efited from the comments of Dr. Barry Roth and anonymous reviewers. LITERATURE CITED BANDEL, K. & C. SPAETH. 1983. Beobachtungen am rezenten Nautilus. Mitteilungen aus dem Geologisch-Paldontolo- gischen Institut der Universitat Hamburg 54:9—26. BuBeL, A. 1983. An ultrastructural investigation of muscle at- tachment in the opercular filament of a polychaete annelid. Tissue and Cell 15:555-572. BUDELMANN, B. U., R. Scuipp & S. VON BOLETZKyY. 1997. Ceph- alopoda. Pp. 119-414 in FE W. Harrison & A. J. Kohn (eds.), Microscopic Anatomy of Invertebrates 6A, Mollusca II. Wi- ley-Liss: New York. DENTON, E. J. & J. B. GILPIN-BROWN. 1966. On the buoyancy of the pearly Nautilus. Journal of the Marine Biological As- sociation of the United Kingdom 46:723-759. Ditty, P. N. & M. Nixon. 1976. The cells that secrete the beaks in octopods and squids (Mollusca, Cephalopoda). Cell and Tissue Research 167:229-241. DOGUZHAEVA, L. & H. Mutvet. 1996. Attachment of the body to the shell in ammonoids. Pp. 43—63 in N. Landman et al. (eds.), Ammonoid Paleobiology 13 of Topics in Geobiology. Plenum Press: New York. GREENWALD, L., C. B. Cook & P. D. Warp. 1982. The structure of the chambered Nautilus siphuncle: the siphuncular epi- thelium. Journal of Morphology 172:5—22. GREGOIRE, C. 1962. On submicroscopic structure of the Nautilus shell. Bulletin Institut royal des Sciences naturelles de Bel- gique 38:1-71. GREGOIRE, C. 1987. Ultrastructure of the Nautilus shell. Pp. 463— 486 in W. B. Saunders & N. H. 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An electron microscope study of the muscle attachment in the mollusc Pinctada ra- diata. Texas Report on Biology and Medicine 28:279—286. SHIMEK, R. L. & G. STEINER. 1997. Scaphopoda. Pp. 719-781 in FE W. Harrison & A. J. Kohn (eds.), Microscopic Anatomy of Invertebrates 6B, Mollusca II. Wiley-Liss: New York. STRICKER, S. A. & C. G. REED. 1985. The ontogeny of shell secretion in Terebratalia tranversa (Brachiopoda, Articula- ta) Il. Formation of the protegulum and juvenile shell. Jour- nal of Morphology 183:251—271. TANABE, K., J. TSUKAHARA, Y. FUKUDA & Y. Taya. 1991. His- The Veliger, Vol. 45, No. 4 tology of a living Nautilus embryo: preliminary observa- tions. Journal of Cephalopod Biology 2:13-22. TANABE, K. & K. UcuHtyAMa. 1997. Development of the embry- onic shell structure in Nautilus. The Veliger 40:203-215. Tompa, A. S. & N. WATABE. 1976. Ultrastructural investigation of the mechanism of muscle attachment to the gastropod shell. Journal of Morphology 149:339-352. WARD, P. & J. CHAMBERLAIN. 1983. Radiographic observation of chamber formation in Nautilus pompilius. Nature 303:57— 3); WENDLING, J. 1987. On the buoyancy system of the cuttlefish Sepia officinalis L. (Cephalopoda). M.D. Dissertation, Uni- versity of Basel, Switzerland. The Veliger 45(4):331—336 (October 1, 2002) THE VELIGER © CMS, Inc., 2002 Range Extensions of Sacoglossan and Nudibranch Mollusks (Gastropoda: Opisthobranchia) to Alaska JEFFREY H. R. GODDARD Marine Science Institute, University of California, Santa Barbara, California 93106, USA AND NORA R. FOSTER University of Alaska Museum, Fairbanks, Alaska 99701, USA Abstract. Range extensions to or within Alaska are described for 16 species of opisthobranch mollusks. The ranges of nine of these, including the sacoglossans Alderia modesta and Olea hansineensis and the arminacean nudibranch Janolus fuscus, are extended northward from British Columbia or southeast Alaska. The ranges of another five species, including four dorids and the arminacean Armina californica, are extended westward from sites within Alaska. The range of an arctic species, Calycidoris guentheri, is extended southward into the central Bering Sea, and that of the circumboreal Palio dubia northeastward to south-central Alaska. Given the circumboreal or amphi-Pacific distributions of about half of these species, as well as the paucity of previous observations in much of Alaska, we consider most, if not all, of these range extensions the result of increased or fortuitous search efforts, rather than actual range expansions by the species themselves. INTRODUCTION Lee & Foster (1985) reviewed the literature and sum- marized the known records of opisthobranchs from Alas- ka, greatly expanding our knowledge of the fauna from the Gulf of Alaska, Bering Sea, and Arctic Ocean. More recently, Foster (1987a, b), Millen (1989), Behrens (1997, 1998), and Goddard (2000) extended the ranges of ad- ditional species to southeast and south-central Alaska; and Millen (1985, 1987) synonymized several species of onchidoridid nudibranchs reported from Alaska. Since these reports, we have continued our studies of the opis- thobranch fauna of Alaska, focusing especially on sites on the Kenai Peninsula and in Prince William Sound dur- ing surveys of non-indigenous marine species led by re- searchers from the Smithsonian Environmental Research Center (SERC) (Hines et al., 2000). In addition, we have examined specimens collected by other researchers and deposited in the University of Alaska Museum since 1985. As a result of these studies, we have extended the known ranges of two sacoglossans and 14 nudibranchs to or within Alaskan waters. This paper documents these range extensions and discusses some of their biogeo- graphic implications. STUDY SITES anp METHODS We searched for opisthobranchs at sites on the Kenai Pen- insula and in Prince William Sound (Figure 1, Table 1), during June and September 1998, August 1999, and July 2000. We collected specimens by hand from intertidal mudflats and rocky shores, floating docks and buoys, rock jetties, and from settling plates deployed in the shallow subtidal by personnel from SERC earlier in the year. We used a dissecting microscope or hand lens to observe specimens alive, and then fixed them in either 5 to 10% formalin or 70% ethanol. Specimens not identified in the field, or those collected by other workers and already de- posited in the University of Alaska Museum, were ex- amined, dissected, and identified in the laboratory at ei- ther the University of California at Santa Barbara or the University of Alaska in Fairbanks. We deposited voucher specimens in the University of Alaska Museum (UAM) in Fairbanks or in the California Academy of Sciences invertebrate zoology collection (CASIZ) in San Francis- co. Catalogue numbers for these are given with the spe- cies accounts below. RESULTS We extended the known ranges of 16 species: nine spe- cies northward from British Columbia and southeastern Alaska, five species westward from sites within Alaskan waters, one species northeastward from the Aleutian Is- lands, and one species southward within the Bering Sea. These species are listed below (alphabetically within each higher taxon) with notes on their classification, habitats, and prey. In addition to the following species, we also found Cu- thona albocrusta (MacFarland, 1966) on floating docks The Veliger, Vol. 45, No. 4 Arctic Ocean Shotgun Cove Whittier Seward Kenai Peninsula CLL Homer y ” ; i, : Kachemak Bay 968 Figure 1. in Cordova, Prince William Sound (Figure 1). Goddard (2000) reported this range extension from southern Brit- ish Columbia, but we only recently deposited the speci- men on which that range extension was based in the Cal- ifornia Academy of Sciences (CASIZ 146069). Sacoglossa Alderia modesta (Lovén, 1844) Adults and their egg masses were abundant on the yel- low-green alga Vaucheria sp. on the high intertidal mud- Fairmont Bay Tatitlek Cordova Prince William Sound Map of the Kenai Peninsula and Prince William Sound, Alaska, showing location of the study sites. flats immediately southwest of the Cordova marina on 13 August 1999. We have deposited three specimens in the California Academy of Sciences (CASIZ 142448). This is a range extension of 1620 km northwest from Port Alice, Vancouver Island, British Columbia (Millen, 1980). Millen (1980:1209) noted that Alderia albopapillosa Dall, 1871, collected by Dall (1871) from Sitka, Alaska, might be synonymous with A. modesta. However, as pointed out by Hand & Steinberg (1955:26), Bergh J. H. R. Goddard & N. R. Foster, 2002 Page 333 Table | Location of study sites for opisthobranch gastropods in south-central coastal Alaska. Longitude Site Latitude (N) (W) Cordova 60°32.50' 145°46.47’ Fairmont Bay 60°53.05’ 147°23.52' Hanning Bay, Montague Island SS” 147°46' Homer spit marina SEBUM WSEAS SIT? Little Takli Island 58°04’ 154°29’ Port Etches, Hinchinbrook Island 60°13’ 146°42' Seward 60°07.43' 149°22.72' Shotgun Cove 60°47.43' = 148°32.50' Tatitlek 60°52.10' 146°43.47' Valdez 61°07.42' 146°21.25' Whittier 60°46.62' 148°41.40' (1880) showed that Dall’s specimens of A. albopapillosa actually belonged to the dorid nudibranch genus Adalar- ia. Millen (1987) later synonomized Adalaria albopapil- losa (Dall, 1871) with Adalaria proxima (Alder & Han- cock, 1854), but did not mention its previous and short- lived placement in the genus Alderia. Olea hansineensis Agersborg, 1923 One specimen (CASIZ 142449) of this opisthobranch egg-eating sacoglossan was found on an egg mass of the cephalaspidean Melanochlamys diomedea (Bergh, 1894) on the mudflat southwest of the Cordova marina on 13 August 1999. This is a range extension of 1825 km north- west from Sechelt Inlet, British Columbia (Millen, 1980). Nudibranchia, Doridacea Adalaria jannae Millen, 1987 This species was abundant, along with its ribbon-shaped egg masses, on the encrusting bryozoan Membranipora sp. growing on the kelp Laminaria sp. on floating docks at Whittier and on a moored buoy in Shotgun Cove, both on 10 August 1999. Owing to the influence of glaciers and snow fields in the fjord surrounding Whittier, the sa- linity (and temperature) of the surface water in the marina was very low, and we found nudibranchs, their prey, and other fouling invertebrates at this site only on Laminaria growing below the fresh water lens. Adalaria jannae closely resembles Onchidoris muricata, but lacks the me- dial radular teeth found in the latter; A. jannae also has four to six small lateral teeth on each half row of the radula, as well as ribbon-shaped egg masses (Millen, 1987). The radular formula from an 8 mm-long (pre- served) specimen from Shotgun Cove was 30 4.1.0.1.4. Eight specimens from Whittier have been deposited in the California Academy of Sciences (CASIZ 142450). This is a range extension 1745 km northwest from Sointula, British Columbia (Millen, 1987). Adalaria sp. 1 of Behrens (1991) and Millen (1987:2701) One specimen (CASIZ 142451), 3.3 mm long (preserved) was found on the low intertidal rocky shore at Tatitlek on 12 August 1999. The morphology of this specimen matched that of specimens observed by one of us (JHRG) in Oregon and Washington (Goddard, 1984, Goddard et al., 1997). This is a range extension of 1080 km northwest from Ketchikan, Alaska (Millen, 1989). Ancula pacifica MacFarland, 1905 A single specimen (CASIZ 142452), lacking orange lines on the body, was found on the floating docks in the Cor- dova marina on 13 August 1999. This species (or just the color form of A. pacifica lacking orange lines on the body) may be a junior synonym of Ancula gibbosa (Ris- so, 1818), which is known from the north Atlantic Ocean and Barents Sea (McDonald, 1983; Thomson & Brown, 1984). This is a range extension of 1080 km northwest from Grant Island, Ketchikan, Alaska (Millen, 1989). Archidoris odhneri (MacFarland, 1966) One specimen (UAM 7153) was collected from unknown depth by R. Baxter 31 January 1985 using a bottom trawl on the continental shelf off the north side of the Alaska Peninsula (57°00'N, 162°03.40’'W) in the Bering Sea. This is a range extension of 660 km southwest from Port Dick on the Kenai Peninsula, Alaska (Robilliard & Barr, 1978). Calycidoris guentheri Abraham, 1876 One specimen (UAM 7154) was collected from unknown depth by R. Baxter 2 September 1985 using a bottom trawl on the continental shelf in the central Bering Sea (57°17.68'N, 178°20.15'W). This is a range extension of 1250 km southwest from the Bering Strait (Lee & Foster, 1985). Diaulula sandiegensis (Cooper, 1863) One specimen (UAM 7155) was collected from unknown depth by R. Baxter 9 October 1986 using a bottom trawl in the central Aleutian Islands (52°21.44'N, 179°49.23'W). This is a range extension of 850 km west from Unalaska Island (Bergh, 1894). Doridella steinbergae (Lance, 1962) Foster (1987a) extended the range of this species from Bamfield, Vancouver Island, British Columbia to Prince William Sound, Alaska. During the present study we found 12 specimens of Doridella steinbergae, 1 to 5 mm Page 334 long, on its prey, Membranipora sp., on drift kelp Lam- inaria sp. on the mudflats at Cordova on 13 August 1999 (CASIZ 146077). We also found this species on Lami- naria sp. in the low rocky intertidal zone at Little Takli Island, Katmai National Park on 27 July 1998, extending its range 475 km southwest from Prince William Sound (Foster, 1987a). Geitodoris heathi (MacFarland, 1905) Four specimens were found on the low intertidal rocky shore at Tatitlek on 12 August 1999; three of these have been deposited in the California Academy of Sciences (CASIZ 142453). This is a range extension of 1080 km northwest from Ketchikan, Alaska (Millen, 1989). Palio dubia (M. Sars, 1829) Adults and egg masses (CASIZ 142454) were abundant on the bryozoan Membranipora sp. growing on the kelp Laminaria sp. on the floating docks at Whittier on 10 August 1999. Additional specimens were found on the buoy at Shotgun Cove on 10 August 1999 and on the docks at Cordova on 13 August 1999. Our specimens were uniformly translucent light brown in color, with del- icate and flaccid bodies, and had five branchial plumes. The rhinophores on one specimen had 12 lamellae. The radula from another specimen had a formula of 15 X 5.2.0.2.5, with the marginal teeth ranging in size from (inner to outermost) 135 to 45 wm high by 50 to 10 pm wide. These characters closely match those of P. dubia described by Thompson & Brown (1984) and Picton & Morrow (1994). They also match Bergh’s (1880) descrip- tion of P. pallida. Thompson & Brown (1984) consider the latter a junior synonym of P. dubia; we concur. The specimens from Cordova represent a range extension of 2450 km northeast from Kiska Island in the Aleutians (Bergh, 1880). Palio dubia has also been recorded from the northern Sea of Japan (Martynov, 1998a). Triopha catalinae (Cooper, 1863) One specimen (UAM 7156) was collected by C. Simen- stad from 6 m depth on 30 June 1987 off Shemya Island (52°43.33’N, 174°07.00’E) in the Aleutians. This is a range extension of 360 km northwest from Amchitka Is- land (Robilliard, 1974). Nudibranchia, Arminacea Armina californica (Cooper, 1863) One specimen (UAM 7157) collected from unknown depth by R. Baxter on 23 September 1986 using a bottom trawl off the north side of Akutan Island (54°16.9'N, 165°57.09'W) in the Aleutian Islands. This is a range ex- tension of 1450 km southwest from Kayak Island in the Gulf of Alaska (Lee & Foster, 1985). Additional speci- The Veliger, Vol. 45, No. 4 mens (UAM 7158 & 7159) were collected by one of us (NRF) in March 1986 from between 102 and 140 m depth in Hanning Bay, Montague Island and between 55 and 129 m in Port Etches, Hinchinbrook Island. Both of these latter sites are in Prince William Sound (Table 1). Janolus fuscus (O’ Donoghue, 1924) Two specimens, 60 and 70 mm long, of this distinctive species were found with their egg masses on the bryozoan Bugula sp. on floating docks in the Homer marina at the mouth of Kachemak Bay on 8 August 1999. We returned these specimens to their habitat after making our obser- vations, confirming their identity, and showing them to others members of the SERC survey team. This is a range extension of 1250 km northwest from Klu Bay, Revilla- gigedo Island, southeast Alaska (Robilliard & Barr, 1978). Nudibranchia, Aeolidacea Cuthona pustulata (Alder & Hancock, 1864) Four specimens (CASIZ 146070), 4 to 5 mm long, were found feeding on the hydroid Sarsia sp. on a dock in the marina at Homer on 8 August 1999. These specimens resembled Gosliner & Millen’s (1984) description of Cu- thona pustulata from British Columbia, especially with regard to overall shape of the body, cerata, and head ten- tacles. However, our specimens were smaller than those examined by Gosliner & Millen (1984) and differed by lacking large white spots on the cerata (they did have smaller opaque white flecks). They also had slightly few- er rows of cerata (six to eight compared to eight to 14), with fewer cerata per row (one to three, compared to two to eight reported by Gosliner & Millen (1984) for a 16 mm-long specimen). The radula and shape of the radular teeth of our specimens were virtually identical to that described by Gosliner & Millen (1984) but differed in having four to five lateral denticles, instead of five to nine. These specimens represent a range extension of 2160 km northwest from Galiano Island, British Colum- bia (Gosliner & Millen, 1984). Eubranchus olivaceus (O’ Donoghue, 1922) We found 10 specimens with their egg masses on the hydroid Obelia sp. growing on floating docks in the Ho- mer marina on Kachemak Bay on 8 August 1999 (CASIZ 146071). We found an additional specimen on Obelia sp. on docks at Whittier on 10 August 1999. The body of these specimens was translucent with small epidermal flecks of either encrusting white or encrusting reddish brown. The cerata, but not the rhinophores or cephalic tentacles, had a subterminal band of encrusting brown pigment. On some specimens, encrusting white pigment was concentrated distally on the rhinophores and cerata. The cerata cores and the branches of the digestive gland J. H. R. Goddard & N. R. Foster, 2002 Page 335 in the body were green to greenish brown, imparting an overall greenish hue to the body. The coloration of these specimens was virtually identical to that observed by Goddard et al. (1997) in specimens from Obelia sp. in Neah Bay, Washington. The specimens from Homer rep- resent a range extension of 970 km west from Amalga Harbor near Juneau in southeast Alaska (Behrens, 1997). Eubranchus olivaceus has also been reported from Ket- chikan, Alaska (Millen, 1989). As described in Just & Edmunds (1985:114), Henning Lemche considered Eubranchus olivaceus very similar to, if not synonymous with, E. rupium (MOller, 1842) from the north Atlantic Ocean. Martynov (1998b) synonymized the former with the latter; he also erected a new genus, Nudibranchus, to include E. rupium and some other spe- cies of Eubranchus based on the branching of the diges- tive gland and details of their reproductive systems. Until the changes proposed by Martynov (1998b) are critically evaluated by other systematists, we consider it expedient to list our specimens under O’ Donoghue’s name. DISCUSSION Dall’s (1871) report of Alderia albopapillosa notwith- standing (see above), no sacoglossans were known from Alaskan waters until Foster (1987a) reported Hermaea vancouverensis O’Donoghue, 1924, from Kodiak and Unga Islands in southwest Alaska. Millen (1983) noted this lack of records of sacoglossans from Alaska com- pared to neighboring regions to the south, and suggested it was due in part to a lack of sampling, as well as to the ease with which these generally small, seasonal herbi- vores can be overlooked. She predicted that more species would eventually be found in Alaska. Millen (1989) then reported Aplysiopsis enteromorphae Cockerell & Eliot, 1905 (as A. smithi (Marcus, 1961)) and Stiliger fuscov- ittatus Lance, 1962, from southeast Alaska; and Behrens (1998) reported Placida dendritica (Alder & Hancock, 1843) from Chichagof Island, southeast Alaska. Our ob- servations of Alderia modesta and Olea hansineensis in Prince William Sound bring to six the number of sacog- lossan species known from the Aleutian biogeographic province, which extends from the Queen Charlotte Is- lands out into the Aleutians and into the Bering Sea as far north as Nunivak Island (Briggs, 1974). All six of these species are also known from British Columbia and California (Millen, 1980; Behrens, 1991), leaving only two species from the Oregonian province, Elysia hedg- pethi Marcus, 1961, and Aplysiopsis oliviae (MacFarland, 1966), yet to be found in Alaskan waters (Behrens, 1991; Trowbridge, 2002). The sacoglossan fauna of the Gulf of Alaska is therefore very similar to that of the neighboring and more extensively studied Oregonian Province, but is probably more seasonal in occurrence owing to the more extreme winter conditions in the former. No sacoglossans are known yet from the Aleutian Islands and Bering Sea, and we did not find any sacoglossans during surveys of Kachemak Bay, off of the lower Cook Inlet, conducted during July 2000. Three of the opisthobranch species whose ranges we extend (Alderia modesta, Palio dubia, and Cuthona pus- tulata) are also known from the north Atlantic and are therefore circumboreal in distribution (Thompson, 1976; Thompson & Brown, 1984). The same may also apply to Ancula pacifica and Eubranchus olivaceus, depending on their above-mentioned taxonomic relationships to the north Atlantic Ancula gibbosa and Eubranchus rupium, respectively. An additional four species (Adalaria jannae, Diaulula sandiegensis, Palio dubia, and Triopha catali- nae) are known from either the Sea of Japan or northwest Pacific Ocean and therefore have amphi-Pacific distribu- tions (Behrens, 1991; Martynov, 1998a, personal com- munication to JHRG 17 February 2001). The same may apply to Eubranchus olivaceus and Alderia modesta, de- pending on their respective relationships to Eubranchus rupium and Alderia sp. reported from the northwestern Pacific by Martynov (1998a, b). One species, Calycidoris guentheri, is strictly arctic in distribution (see Platts, 1985; Lee & Foster, 1985), and the remaining species (Olea hansineensis, Adalaria sp. 1, Archidoris odhneri, Doridella steinbergae, Geitodoris heathi, Armina califor- nica, Janolus fuscus, Cuthona albocrusta) are found only in the northeastern Pacific (Behrens, 1991). The propor- tion of species with these different distributions reflect those for the Alaska opisthobranch fauna as a whole (see Lee & Foster, 1985). Most of the range extensions documented above are for species that are either: (1) easily overlooked (owing to their small size, cryptic coloration, or seasonal occur- rence), (2) recorded for the first time from remote, little- studied parts of Alaska, or (3) already known from both the northeastern Pacific Ocean and either the north At- lantic Ocean or the northwest Pacific Ocean. Therefore, we consider most, if not all, of these range extensions to be the result of increased or fortuitous search efforts, rath- er than actual range expansions by the species them- selves. One possible exception to this may be represented by Janolus fuscus, a conspicuous arminacean that com- monly reaches 30 to 40 mm in length (personal obser- vations). Extensive faunal surveys conducted along the entire coast of British Columbia in the 1950s and 1960s found this species only as far north as central Vancouver Island (Bernard, 1970). Lambert (1976) and Robilliard & Barr (1978) then extended the range of J. fuscus to sites in southeast Alaska. While these and our own records are consistent with a recent range expansion by this species, we cannot rule out that J. fuscus has been a rare or in- termittent member of the Alaskan fauna for a much lon- ger time period. Acknowledgments. Much of our research was conducted as part of a larger study of non-indigenous species in Prince William Sound. This latter study was funded by the Regional Citizen’s Page 336 Advisory Council of Prince William Sound, U.S. Fish and Wild- life Service, National Sea Grant, Smithsonian Environmental Re- search Center, Maritime Studies Program with Williams College, Alyeska Pipeline Service Company, SeaRiver Maritime, ARCO Marine, and British Petroleum. We are grateful for all their sup- port. We particularly thank Drs. Greg Ruiz and Anson Hines for the opportunity to participate in the surveys, Elise Schickel for assistance in the field with collecting and record keeping, and the community of Tatitlek for their hospitality and permission to examine their rich intertidal shores. We thank the staff of the Department of Invertebrate Zoology at the Santa Barbara Mu- seum of Natural History for assistance in obtaining literature per- tinent to this study, and Dr. Alexander Martynov for sending us English translations of his papers on the opisthobranchs of the northwestern Sea of Japan. Finally, we are grateful to Sandra Millen for alerting us to Dr. Martynov’s work and for her advice on matters of nomenclature. LITERATURE CITED BEHRENS, D. W. 1991. Pacific Coast Nudibranchs. Sea Challeng- ers: Monterey, California. 107 pp. BEHRENS, D. W. 1997. Locality data: Eubranchus olivaceus (O’ Donoghue, 1921). Opisthobranch Newsletter 23:18. BEHRENS, D. W. 1998. Locality data; Placida dendritica (Alder & Hancock, 1843). Opisthobranch Newsletter 24:41. BerGu, L. S. R. 1880. On the nudibranchiate gasteropod Mol- lusca of the north Pacific Ocean, with special reference to those of Alaska. Part II. Proceedings of the Academy of Natural Sciences of Philadelphia 32:40—127. BerGu, L. S. R. 1894. Die Opisthobranchien. Reports on the dredging operations off the west coast of Central America to the Galapagos, to the west coast of Mexico, and in the Gulf of California. XIII. Bulletin of the Museum of Com- parative Zoology at Harvard College 25:125—333. BERNARD, E R. 1970. A distributional checklist of the marine molluscs of British Columbia: based on faunistic surveys since 1950. Syesis 3:75—94. Briccs, J. C. 1974. Marine Zoogeography. McGraw-Hill: New York. 475 pp. DaALL, W. H. 1871. Descriptions of sixty new forms of mollusks from the West Coast of North America and the North Pacific Ocean, with notes on others already described. American Journal of Conchology 7:93—160. Foster, N. R. 1987a. Range extension for Doridella steinbergae (Lance, 1962) to Prince William Sound, Alaska. The Veliger 30:97—-98. Foster, N. R. 1987b. Hermaea vancouverensis O’ Donoghue, 1924, from Kodiak Island and Unga Island, Alaska. The Veliger 30:98. GopDARD, J. H. R. 1984. The opisthobranchs of Cape Arago, Oregon, with notes on their biology and a summary of ben- thic opisthbranchs known from Oregon. The Veliger 27: 143-163. GopDArRD, J. H. R. 2000. Northern and southern range extensions of the aeolid nudibranch Cuthona albocrusta. Opisthobranch Newsletter 26:9. GoppDArRD, J. H. R., T. R. WAYNE & K. R. Wayne, 1997. Opis- thobranch mollusks and the pulmonate limpet Trimusculus reticulatus (Sowerby, 1835) from the outer Washington coast. The Veliger 40:292—297. GOSLINER, T. M. & S. V. MILLEN, 1984. Records of Cuthona pustulata (Alder & Hancock, 1854) from the Canadian Pa- cific. The Veliger 26:183—187. The Veliger, Vol. 45, No. 4 HAND, C. & J. STEINBERG. 1955. On the occurrence of the nu- dibranch Alderia modesta (Lovén, 1844) on the central Cal- ifornia coast. The Nautilus 69:22—28. Hines, A. H., G. M. Ruiz, J. CHAPMAN, G. I. HANSEN, J. T. CARL- TON, N. FosTeR & H. M. FEDER. 2000. Biological invasions of cold-water coastal ecosystems: ballast-mediated introduc- tions in Port Valdez/Prince William Sound, Alaska. Final Report to the Prince William Sound Citizen’s Advisory Council, U.S. Fish and Wildlife Service and National Sea Grant Program. Just, H. & M. Epmunps. 1985. North Atlantic Nudibranchs (Mollusca) Seen by Henning Lemche. Ophelia Publications: Marine Biological Laboratory, Helsinggr, Denmark. 170 pp. LAMBERT, P. 1976. Records and range extensions of some north- eastern Pacific opisthobranchs (Mollusca: Gastropoda). Ca- nadian Journal of Zoology 54:293—300. Lee, R. S. & N. R. Foster, 1985. A distributional list with range extensions of the opisthobranch gastropods of Alaska. 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Canadian Journal of Zoology 56:152-153. THompson, T. E. 1976. Biology of Opisthobranch Molluscs. Vol. I. Ray Society: London. 207 pp. THompson, T. E. & G. H. Brown. 1984. Biology of Opistho- branch Molluscs. Vol. II. Ray Society: London. 229 pp. TROWBRIDGE, C. D. 2002. Northeastern Pacific sacoglossan opis- thobranchs: natural history review, bibliography, and pro- spectus. The Veliger 45(1):1—24. THE VELIGER © CMS, Inc., 2002 The Veliger 45(4):337—355 (October 1, 2002) Mollusca of Assateague Island, Maryland and Virginia: Additions to the Fauna, Range Extensions, and Gigantism ROBERT S. PREZANT;' CLEMENT L. COUNTS, III’ anp ERIC J. CHAPMAN! ‘Department of Biology and Molecular Biology, College of Science and Mathematics, Montclair State University, Upper Montclair, New Jersey 07043, USA *Department of Natural Sciences, University of Maryland Eastern Shore, Princess Anne, Maryland 21853-1299, USA Abstract. Collections of 108 species of marine and estuarine mollusks from and around Assateague Island, Maryland and Virginia, from 1991 to 1996, vary from and extend the known species lists generated by three previously published collections over the past 100 years. Extensive sampling, including benthic grabs, trawls, and hand collecting, has added 54 species of mollusks (20 bivalves, 31 gastropods, one polyplacophoran, and two cephalopods) to the 1914 list of Henderson & Bartsch and 46 (19 bivalves, 26 gastropods and one cephalopod) to that of Counts & Bashore from 1991. Homer et al. in 1997 provided a mollusk survey of Maryland coast bays and listed 73 molluscan species (including 10 species recorded as shells only and eight as taxonomic uncertainties). To the latter we have added 51 molluscan taxa they did not find (19 bivalves, 29 gastropods, one polyplacophoran, and two cephalopods). All collections represent a total described malacofauna of this region of 146 shallow-water species excluding undescribed or non-described taxa in earlier papers. Within the populations of some of the species collected were a few exceptionally large individuals, adding to previous records of unusually large specimens of mollusks from this region of the Atlantic coast. Additionally, some species of mollusks (Tectura testudinalis, Eupleura semisulcata [Gastropoda], Tridonta borealis [Bivalvia]) and some non-mollusks (the ascidian Ecteinascidia turbinata and a confirmation of an extension of the anthozoan Peachia par- asitica) have been found in the waters surrounding Assateague, well outside of their previously reported geographic ranges. The results of the present study suggest the need for a re-evaluation of possible environmental shifts that could have taken place since the collections of the early 1900s and have elsewhere been implicated in the change of mala- cofauna of Assateague Island since that time. Additionally, range extensions reported could reflect a subtle geographic transition zone, newly introduced species, or, most likely, an understudied coastal area. INTRODUCTION Three previous notable surveys of marine and estuarine mollusks have been conducted at or just adjacent to As- sateague Island along the Maryland and Virginia, USA, coast. The first, by Henderson & Bartsch (1914), reported 37 species of bivalves and 44 species of gastropods from nearby Chincoteague Island, Virginia, from collections made during the course of a week in the summer of 1913. Fourteen of the gastropods reported in their study were described as new species. In particular, among other gas- tropods, they described as new some very small snails including: Bittiolum alternatum virginicum, Odostomia pocahontasae, O. virginica, Turbonilla pocahontasae, T. powhatani, T. toyatani, and T. virginica. Among the 14 new species were three others they believed were new but of which the specimens were “‘too poor to serve for description”’ (Henderson & Bartsch, 1914). It is unlikely that these latter specimens truly represent new species. Within the individual genera, their other ‘“‘new species” are often difficult to distinguish as morphologically unique, and some are likely subtaxa or ecophenotypes of other species, e.g., Diastoma virginica Henderson & Bartsch 1914 = Bittiolum alternatum virginicum = prob- ably a variant of Bittiolum varium (Pfeiffer, 1840). The validity of several of their new species awaits detailed examination, as many other species described as new by Bartsch have already been placed in synonomy of pre- viously described taxa. Counts & Bashore (1991) made similar collections between April 1988 and August 1989, but expanded their geographic coverage to include all of Assateague Island. They found 73 species of mollusks, 32 species of bivalves, 39 species of gastropods, and one species each of Polyplacophora and Cephalopoda. How- ever, of the 81 valid or newly described species of Mol- lusca reported by Henderson & Bartsch, only 50 were reported as still present 75 years after their 1913 collec- tion, and Counts & Bashore (1991) reported an additional 25 species not found during the study of Henderson & Bartsch. More recently, Homer et al. (1997) surveyed the mollusks of the Maryland coast in a “‘shellfish inventory” for the Maryland Department of Natural Resources. The latter study was intended to form a baseline for ‘future management needs” of the Maryland coast, in particular for commercially important mollusks (e.g., Crassostrea virginica, Mercenaria mercenaria) of the region. They Page 338 recovered 63 live molluscan taxa during their study plus 10 species represented by shells only. Of their recovered species, 16 were previously unrecorded from the Mary- land coast. During several collections from 1994-1996, we found live representatives of 101 species and valves of an ad- ditional seven species of mollusks from along areas com- parable to these other collections. Our data showed sig- nificant variation in the malacofauna reported in all pre- vious studies plus some interesting range extensions, and evidence of “‘gigantism’’ among some of the mollusks in the area. This study collected 27 species of mollusks not recorded in the previous three major studies. Similarly, each of the studies had at least some species not found by the others. The faunal variations found among the var- ious studies are significant, and while our overall collec- tion most closely overlaps with that of Counts & Bashore (1991) Gin terms of most species matches), interesting dif- ferences appear between various collections of gastropods and between all pairs of previous collections. If nothing else, it is clear this mid-Atlantic coastal region has a wide array of microhabitats that hold many hitherto unrecorded taxa. METHODS Quantitative and qualitative sampling was carried out dur- ing midsummer, late autumn, and early spring during 1994, 1995, and 1996. All primary shallow-water marine habitats along coastal Assateague and Chincoteague were sampled. Qualitative samples were taken at irregular sites along Assateague, Maryland, and Virginia (Figure |) with kicknets, Yabby pumps, trawls, seines, and by hand col- lecting. Habitats sampled qualitatively included jetties, extensive mudflats (Tom’s Cove, Little Tom’s Cove, and Wash Flats), benthic trawls (especially in Cockle and Mosquito creeks), grabs to depths of 15 m (especially near the mouth of Chincoteague Bay at Turner’s Lump and adjacent waters), and oyster beds. The rock jetty at Memorial Park, Chincoteague was also carefully searched for epifauna and crevice dwellers. Since the time of col- lection, the original rock jetty at Memorial Park has been replaced with a much more extensive wooden (treated) and rock structure and boat launch. Additionally, we sam- pled the eelgrass beds adjacent to nearby Greenbackville, Virginia. As part of a larger survey of macroinvertebrates of Assateague Island (Counts & Prezant, 2001), sampling stations were established along transects at uniform dis- tances from shore and/or water depths along the island to include ocean near-shore sandy bottom, bay sandy bot- tom, bay submerged aquatic seagrass beds, bay intertidal mudflats, fringing marshes, and bay muddy bottom/tidal gut/embayments. Specifically (Figure 1), along each of four separate oceanside transects (O-2, O-7, O-12, O-16), three sampling stations were established at mid-swash The Veliger, Vol. 45, No. 4 zones, 5 m from shore (subtidal), and 25 m from shore (also subtidal). Twelve transects within Chincoteague Bay were established (B-1 through B-4 and B-7 through B- 16), each with four sampling stations that included: mid- swash zone, 0.5 m depth relative to mean high tide (sub- tidal), 1.0 m depth (subtidal), and 1.5 m depth (subtidal). Six replicates were taken at each site with a small box core sampler. These individual sites are described in the the next section. All samples were preserved with 5% (CaCO,;) buffered formalin, washed in water and transferred to 70% ethanol for storage. Identifications were made in the laboratory using standard reference works. Collections have been deposited in the mollusk collections of Montclair State University, the University of Maryland Eastern Shore, and the American Museum of Natural History, New York. Our qualitative data allowed a comparison with the few more complete compilations of molluscan taxa collected from the Assateague and Chincoteague coasts. We used a Bray-Curtis similarity index using PRIMER version 5.0 (Plymouth Routines in Multivariate Ecological Research, Carr [1997]) to compare our species list with those com- piled by Henderson & Bartsch (1914), Counts & Bashore (1991), and Homer et al. (1997). Additionally, we used this program to perform cluster analyses among the var- ious studies to find highest levels of similarity in collec- tions. In all analytical work, we discounted any taxa not fully identified in previously published work (e.g., Tur- bonilla sp.). RESULTS anp DISCUSSION Description of the Study Area Assateague Island is a barrier island system located on the southern Atlantic coast of Maryland extending south- ward to the northern coast of Virginia (Figure 1). The island is approximately 58 km in length and averages 0.8 km in width. It is bounded on the north by Ocean City Inlet (separating Assateague from Fenwick Island), on the south by Chincoteague Inlet, on the east by the Atlantic Ocean, and on the west by Sinepuxent and Chincoteague Bays. The average depth of Sinepuxent Bay ranges from 1.0 to 1.5 m, with a 2 m deep channel, and deepens to 5—6 m at Ocean City Inlet. The maximum width of Chin- coteague Bay is 11.6 km, and the entire back bay system has an area of 428.9 km? (Biggs, 1970). The depth of Chincoteague Bay ranges from 1 to 3 m, deepening to 38 m at Chincoteague Inlet. The southern end of the island contains Tom’s Cove, formed by an eastward-bending sand spit (Fishing Point) and the main body of the island. The average depth of Tom’s Cove is 1 m. Seiling (1954) described the physical characteristics of the waters surrounding Assateague Island. In summer months, water temperatures are cooler at the inlets and warmer in the shallow bays. In the winter, the pattern is Rais, Prezant et al-, 2002 Page 339 Ocean City Inlet oe Sinepuxent Bay QP x = Assateague Island ( © Atlantic Ocean Greenbackville Maryland Virginia Chincoteague Island Wash Flats Mosquito Creek Memorial Park Queen Sound Cockle Creek ax SS Little Tom's Cove — y & 7 Tom's Cove ee — Chincoteague Inlet Wallops Island Turner's Lump Figure 1. Assateague Island, Maryland and Virginia. The map shows transect lines along Chincoteague Bay (represented by B-transect lines) and ocean coast (represented by O-transect lines). See text for description of transect sites. Other sampling areas are labeled by name. Page 340 reversed, and occasionally the bays will freeze over. In summer, salinities decrease toward the inlets where tidal surge mixes seawater with high salinity bay water. The salinity pattern reverses during the winter and spring months. Summer salinity patterns result from a net loss from evaporation that is made up by tidal inflow and min- imal freshwater inflow streams on the mainland (Pellen- barg & Biggs, 1970). Summer 1989 was characterized by higher than usual rainfall, and salinities ranged from 24 to 35 ppt in Chincoteague Bay, the highest salinities being measured at the inlets. Tidal amplitudes are not remark- able, being approximately 1 m at the inlets and 0.33 m in the bays. Tidal currents of Chincoteague and Sinepux- ent bays are mostly independent of the non-tidal oceanic currents, and water flows away from the inlets at Ocean City and at Chincoteague as the tide rises (Pellenbarg & Biggs, 1970). Bay water circulation is such that the total water movement of the bays allows a daily water ex- change of approximately 7.5% from outside sources (Prit- chard, 1960). Pellenbarg & Biggs (1970) reported the bays to be essentially stagnant and intensely heated and stratified during the summer months. Seiling (1954) noted that currents throughout the bays, although of no great magnitude, could have some influence on shellfish larval distribution. Atlantic coastal waters of Assateague Island are shal- low, and Pellenbarg & Biggs (1970) noted that they be- come rapidly stratified by mid-April and that there is little mixing between thermally stratified waters. Summer sur- face currents are generally onshore, and the entire water mass has a northerly drift, perhaps due to the nearby Gulf Stream (Pellenbarg & Biggs, 1970). While the overall exposed beach along Assateague was quite uniform (mid-energy medium course sand _ sedi- ment), the bay side was somewhat variable. The sites used for transects (as indicated on Figure 1) include the following (B = Bay side; O = Ocean side): B-1: 1 km south of Ocean City Inlet. A sandy shore bordering a Spartina alterniflora dominant marsh. Rela- tively firm substratum with some fragmented macroalgae accumulations. The 1.0 m depth site along the transect was located 40 m from shore indicating a relatively shal- low beach slope. Sediments from deeper (0.5 and 1.0 m depths) sites were muddy with a diatom or cyanobacter coating (slippery surface over firm mud). Sediments from all depths had a hydrogen sulfide odor, which was stron- gest at the 0.5 m depth site. B-2: 3 km south of Ocean City Inlet. The swash zone occurred as an overwash flat with soft sediments; sporad- ic algal clumps; swash zone sediment was dark colored with hydrogen sulfide odor; 0.5 m depth subtidal sedi- ments had a muddy silt covering. The gently sloping beach dropped to the 1.0 m depth site at 50 m from the swash zone. B-3: 5 km south of Ocean City Inlet. Swash zone is an eroding salt marsh perimeter. Substratum in swash had The Veliger, Vol. 45, No. 4 a hydrogen sulfide odor; no odor from subtidal sediments; No shell fragments. 1.0 m depth site located 50 m from shore. B-4: 7 km south of Ocean City Inlet. Very shallow decline to about 0.75 m. Sandy sediments. No sulfide odors in sediments collected. 1.0 m depth station located 80-85 m from shore. B-7: 13 km south of Ocean City Inlet. Swash zone along a Spartina marsh gut, other station sites within gut. Turbid water caused by suspended solids; sediment an- aerobic close to surface. Steeper slope beach with 1.0 m depth located 10 m from shore. Some submerged vege- tation at 1.0 m depth. B-8: 15 km south of Ocean City Inlet. Very shallow sloping beach with swash zone within Spartina marsh and 0.5 and 1.0 m depth stations in embayment. 1.0 m depth station located 125 m from shore. Sandy, firm substratum; anaerobic in shallower stations. B-9: 17 km south of Ocean City Inlet. Beach front a bit steeper with 1.0 m meter station located 30 m from shore. Swash zone at edge of shallow gut with 0.5 m and 1.0 m stations located within submerged aquatic vegeta- tion (SAV). Soft sediments black to gray in color. B-10: 19 km south of Ocean City Inlet. Swash zone along marsh front with deeper stations in shallow gut about 45 m from shore. Plant fragments in swash zone; swash zone sediments with hydrogen sulfide odor. B-13: 25 km south of Ocean City Inlet. Very shallow beach with 1.0 m depth located 140 m beyond swash zone. Entire station part of a tidal flat with fine sand sub- stratum; only swash zone sediment had a sulfide odor. B-14: 27 km south of Ocean City Inlet. 1.0 m depth located only 15 m from shore, comparatively steep beach. Swash zone an eroding marsh front; 1.0 m depth station with SAV (Zostera marina). Swash zone sediment clumped mud grading to fine to medium sands with in- creasing depth. B-15: 29 km south of Ocean City Inlet. Relatively steep beach with 1.0 m depth located 20 m from shore. Swash zone part of Spartina marsh; 1.0 m depth with SAV. Firm substratum with sulfide odor in swash zone sediments only. B-16: 31 km south of Ocean City Inlet. Relatively steep beach with 1.0 m depth located 20 m from shore. Swash zone is part of Marsh Island Cove, a low Spartina marsh. Eelgrass beds at 0.5 and 1.0 m depths. Swash zone sediments with sulfide odor. Sediments in swash zone muddy with probable cyanobacter and/or diatom cover. Deeper sites with sandier substratum. Ocean sites were located in direct line with bay sites B-2, 7, 12, and 17 and were nearly identical in general appearance: fine to medium sand, low to mid-energy beaches with mid-grade slope. Each ocean transect had samples taken (six replicates) at the swash zone, 0.5 and 1.0 m depths. R. S. Prezant et al., 2002 Page 341 Malacofauna, Environment, and Changes through Time and among Studies Assateague and Chincoteague Islands and their near- shore environments offer a wide array of soft sediment habitats ranging from mud flats to marshes, sea grass beds to sand beaches. Numerous jetties and piers add artificial hard substrata that are densely colonized by epifauna. Oyster beds, natural and planted, offer an additional hard surface and crevice habitat for various mollusks. A large number of variably detailed general surveys have includ- ed at least part of our study sites. Casey & Wesche (1981) examined the coastal benthos of Maryland’s bays. Their seasonal collections included two locations in Chinco- teague Bay. Using an otter trawl (6.35 mm mesh) and a Ponar grab (sieved at 1.0 mm), they recovered a total of 15 species of mollusks. They also collected another 142 species of non-molluscan benthic organisms. In all of their samples, Mytilus edulis dominated in terms of sheer numbers, composing 87% of all individuals collected (T = 50,033 in spring and winter samples). The bias toward M. edulis probably indicates a bias in sample sites and thus sampling substratum and habitat. Blue mussels are frequently not only dominant organisms in terms of sheer numbers in a community, but also can serve to inhibit settlement of other species, thus reducing overall diver- sity. Seasonally, however, the authors found a significant overall decline in the number of organisms and number of taxa recovered from their spring sampling period (late April to early May) to their summer sampling (late July to early August). In spring 1981, they collected 11 species of mollusks. This dropped to nine in the summer collec- tion. In fall 1981, they collected nine species of mollusks (six gastropods, three bivalves) while in their winter col- lection this dropped to a total of five (two gastropods, three bivalves). The most commonly collected species for all seasons combined was the relatively small Tellina agilis, an infaunal bivalve usually inhabiting fine sand to mud. The likelihood that there were only 15 species of mollusks present during the latter study is remote. More likely, the low diversity reflects a combination of com- promised sampling techniques (the authors allude to grab samples that lacked adequate “‘bite’’), relatively infre- quent sampling, and poor preservation (some specimens were difficult to identify because of preservation prob- lems). Similar to the study noted above, Drobek et al. (1970), in a final report on the environment of Assateague Island, listed only 12 species of mollusks. These authors sampled 64 sites within Chincoteague Bay, from Ocean City Inlet to the Virginia border, using a shallow-water escalator harvester. They note that this ““gear permits a quantitative removal from the bottom of all bottom-dwelling animals over approximately 1 cm in length.”’ Thus, their sampling missed the smaller biota. More comprehensive studies targeted the malacofauna specifically and revealed a much more diverse molluscan biota. Henderson & Bartsch (1914) reported 81 species (excluding two Turbonilla that they presumed new but did not describe) from Chincoteague Island. Counts & Bashore (1991) found 73. (Note: The text and tables in Counts & Bashore [1991] are not in agreement; the ap- propriate counts for that paper are taken from their Table 1.) Homer et al. (1997) reported a total of 73 molluscan taxa from the Maryland coast. We found 108 species of mollusks from this region (Table 1), a total greater than that in any previous study. In all studies combined, there are 146 species of mollusks listed from this region (also excluding undescribed or nondescribed taxa listed by Ho- mer et al. [1997]). Homer et al. (1997) suggested that there were several factors that could be associated with the molluscan diversity found. These include the poly- haline environment that “allows the more tolerant marine species to exploit this system, adding to the true estuarine species.’ Additionally, they note the diversity of benthic habitats based on a wide array of sediment types as a possible factor accounting for the relatively high mollus- can diversity. In our collections, mollusks were found in a wide array of habitats that reflect the diversity of sub- strata and other resources available in the region for ini- tial settlement (see Table 2 for listing of general habitat distribution and specific localities based on transects). Lastly, Homer et al. (1997) suggested that the location of Chincoteague Bay offers a transitional zone, located at the south end of the Virginian province, allowing a blend- ing with several Carolinian species. Nevertheless, among all studies through time, we see significant differences among total species listed. We found 47 species of bivalves, compared to 32 by Counts & Bashore (1991), 37 by Henderson & Bartsch (1914), and 31 by Homer et al. (1997) (Table 3). Of these, we found 19 not reported by Counts & Bashore (1991), 20 not found by Henderson & Bartsch (1914), and 19 not reported by Homer et al. (1997) (Table 4). On the other hand, Counts & Bashore reported six bivalve species we did not discover, Henderson & Bartsch found 10 not on our present list, and Homer et al. (1997) reported three that we did not recover. These kinds of differences are evaluated more carefully below where we examine spe- cific similarities and differences in malacofauna. In some cases they represent subspecies of questionable validity; in others, they could represent drift of empty valves (re- ported as such in our study but not differentiated from living mollusks by Henderson & Bartsch (1914) and Counts & Bashore (1991). In all, the three earlier studies and the present study have a total overlap of only 13 species of bivalves. We found nine species of bivalves not found by Henderson & Bartsch (1914), Counts & Bashore (1991), nor Homer et al. (1997). Thus only about 22% of the species of bivalves we found in the present study were found in all three previous studies. Of the 58 reported gastropods in the present study, we Page 342 The Veliger, Vol. 45, No. 4 Table 1 Mollusca of Assateague Island, Maryland and Virginia. A comparison of results from Henderson & Bartsch (1914) (A), Counts & Bashore (1991) (B), Homer et al. [coastal Maryland study, 1993-1996] (1997) (C) and the present study (D). Notes are presented in right hand column. + = Present; — = Absent; G = “‘Giant’’ specimen(s); R = Range extension; S = Shell only. (Note: Counts Bashore [1991] did not distinguish live animals from shells only.) In cases where the taxonomic validity of a particular species is in question (either because of a debate or question in the literature; overviews in Turgeon et al., 1998), it is also indicated under the notes column. Undescribed species, species thought to be new, or nondescribed taxa (e.g., two species of Turbonilla in Henderson & Bartsch and seven species of gastropods in Homer et al. listed as sp.) are not included in this list nor in any numerical analyses. Species A B Cc D Notes BIVALVIA Abra aequalis (Say, 1822) cts = = a Aligena elevata (Stimpson, 1851) Anadara ovalis (Bruguiére, 1789) + + + + Scapharca campechiensis pexata in Henderson & Bartsch (1914) Anadara transversa (Say, 1822) + oF ar + Scapharca transversa Say in Hender- son & Bartsch (1914) Anomia simplex d’Orbigny, 1842 + + at F Anomia glabra also listed by Hender- son & Bartsch (1914) but almost certainly an error Argopecten gibbus (Linnaeus, 1758) + aF = = Henderson & Bartsch (1914) list as Pecten gibbus irradians—probably a juvenile A. irradians irradians Argopecten irradians £. concentricus (Say, 1822) = ate = = Planted by M. Castagna, VIMS, Wachapreague, VA Argopecten irradians irradians (Lamarck, 1819) = + S S Planted by M. Castagna, VIMS, Wachapreague, VA Astarte castanea (Say, 1822) + + — Barnea truncata (Say, 1822) = + = + Brachidontes exustus (Linnaeus, 1758) a 7 73 al Chione cancellata (Linnaeus, 1767) + + = S Circomphalus strigillinus (Dall, 1902) = = = + Cyrenoidea floridana (Dall, 1896) t Corbula contracta Say, 1822 a = = + Crassinella lunulata (Conrad, 1834) + + — = Crassostrea virginica (Gmelin, 1791) ar aR at ar Cyclinella tenuis (Récluz, 1852) = — R _ Cyclocardia borealis (Conrad, 1831) + + — — Venericardia granulosa Say = Cardi- ta borealis Henderson & Bartsch in Henderson & Bartsch 1914) Cyrtopleura costata (Linnaeus, 1758) + + + + Dinocardium robustum (Lightfoot, 1786) S = = = Divaricella quadrisulcata (d’Orbigny, 1842) + + = S Donax variabilis Say, 1822 + + + + Ensis directus Conrad, 1843 = ap yesh; a5 Ensis minor Dall, 1900 als a oa ae Gemma gemma (Totten, 1834) = + + + Very common on mudflats, within Limulus depressions Geukensia demissa (Dillwyn, 1817) — + + + Gouldia cerina (C.B. Adams, 1845) = = = + Ischadium recurvum (Rafinesque, 1820) = ar at mi Laevicardium mortoni (Conrad, 1830) at 7 = a Linga pensylvanica (Linnaeus, 1758) S = = = Phacoides aurantia Deshayes in Hen- derson & Bartsch (1914) Lyonsia hyalina Conrad, 1831

Table 8 Molluscan species demonstrating “‘gigantism’’ (or exceptionally large size) at Assateague Island. Dimensions of Assateague specimens from present study or as noted. Size of specimens denoted from literature have not been verified here. True “giants” (here defined as at least 25% larger than previously recorded maximum size) are indicated with an asterisk. Species BIVALVIA *Tyonsia hyalina GASTROPODA Bittiolum alternatum virginicum Busycon carica *Crepidula convexa Crepidula fornicata Urosalpinx cinerea folleyensis Previously reported dimensions Dimensions of assateague specimens 12.68 to 19.02 mm shell length (Abbott, 1974) Possibly a giant ecological form of Bittiolum alternatum (Say, 1822); shell height of 6.3 mm (Abbott, 1974) 125.85 to 228.33 mm in length (Abbott, 1974) (but recorded at 281 mm from S. Carolina in Hutsell et al. 1999) 6.34 mm to 12.68 mm (Abbott, 1974) 19.02 to 51.74 mm (Abbott, 1974) (but re- corded at 66.7 mm (no locality data) in Hustell et al., 1999) 68.3 mm from Washington noted (Hutsell et 25.5 mm shell length, 14.2 mm shell height; rate in area Exceptionally large specimens of 8.3 mm from Chincoteague recorded in Henderson & Bartsch (1914) as Diastoma virginica n. sp. 253 mm shell length 24.5 mm Many large specimens, largest being 58.7 mm; all female stage Exceptionally large Delmarva specimens re- al., 1999) POLYPLACOPHORA *Chaetopleura apiculata 7 to 20 mm in length (Abbott, 1974) ported by Baker (1951) and from Chinco- teague by Henderson & Bartsch (1914) 30.5 and 40.0 mm in length, four remarkably large specimens; rare in area tion, environmental energetics (i.e., high wave intertidal versus quiescent mud flat), population density, offspring size, temperature, and other environmental variables (Branch & Branch, 1980; Branch, 1981; Underwood, 1984a, b; Bowling, 1994; Schindler et al., 1994; Sibly & Atkinson, 1994; Strayer, 1994; Atkinson, 1995; Takada, 1995; Kozlowski, 1996; Yampolosky & Schneiner, 1996). Homer et al. (1997) noted that coastal bay populations of Nassarius vibex tend to reach larger sizes than usually reported (they found that N. vibex in Chincoteague Bay averaged 15.8 mm long with a range between 9.0—18.0 mm, whereas “‘shell guides”’ typically report them to be smaller). Causative effects of within-habitat variation in size of relatively sedentary mollusks can reflect tide level and differences in microhabitat (Sutherland, 1970; Creese, 1980: Fletcher, 1984; Takada, 1995). Ost & Kilpi (1997) and Kautsky (1982) discussed a variety of envi- ronmental parameters that influence the maximum size of the blue mussel Mytilus edulis in Baltic waters. These include temperature, salinity, wave and light exposure, food supply, and population structure. Parasitism is also an occasional cause of gigantism in some snails (Mour- itsen & Jensen, 1994). For example, trematodes of “‘low- pathogenecity”’ have been shown to cause gigantism in Hydrobia spp. (Gorbushin, 1997). De Jong-Brink (1995) suggested that trematodes could influence neuroendocrine functions in snails (in this case Lymnaea stagnalis) and induce increased growth. Baker (1951) reported a case of “gigantism”’ of Urosalpinx cinerea folleyensis from Chincoteague. Similarly, Henderson & Bartsch (1914) noted the “‘enormous size’’ of specimens of this gastro- pod taken from Chincoteague oyster beds. In the present study, we found exceptionally large specimens of two species of bivalve, four species of gastropod, and the chi- ton Chaetopleura apiculata (Table 8). These mollusks range from filter feeders (Lyonsia hyalina and Crepidula convexa) to grazing herbivores (Chaetopleura apiculata) to predatory carnivores (Busycon carica). None were found in particularly large numbers and there was little evidence of disproportionately intense predation of small- er cohorts of the filter feeders or grazers, although only large Chaetopleura apiculata and Lyonsia hyalina were found. The list includes both infaunal and epifaunal spe- cies, subtidal and intertidal species, and common and rare species. Nevertheless, L. hyalina and C. apiculata are noteworthy for their extreme sizes. Tablado et al. (1994) found that the pulmonate limpet Siphonaria lessoni grew to larger sizes in sewage polluted areas of Argentina. These authors suspected the cause of larger snails was either directly or indirectly a result of organic enrichment. The anthropogenic input in the As- sateague region is relatively high, especially during sum- mer tourist season. However, the larger specimens found in our study represented only a small minority of the total population (except for Chaetopleura apiculata, which had an overall small population), and it seems unlikely that any general environmental factor could be causative. Recent studies by Rex & Etter (1997) showed that both Page 354 larval and adult shells increase in size with depth into the abyss. They suggested that the decreased input of nutri- ents into these deep waters will select for the larger spec- imens that would have a competitive or metabolic advan- tage. Whether this is accurate or not, it is clear that lo- cation plays a significant role in size distribution. Chin- coteague and Assateague are in the Boreal province and Virginian subprovince. The region offers a wide array of temperate marine and estuarine habitats that are not as warm as those to the south or as seasonally cool as those to the north. While not a delineated provincial zone, this region offers a blend or transition between the Carolinian province and the Boreal. Although Cape Hatteras is the identified division between these provinces, temporal var- iations in the Gulf Stream can bring decisively Carolinian fauna up along Assateague. Similarly, shifts in the Lab- rador Current can bring cooler water species south. Such displaced species are common along northern coastal Vir- ginia and southern Maryland (see list of range extensions; also note that during these collections several species of semitropical fish [e.g., Chaetodon] were found along our field sites). Does the integrative nature of this region in- fluence growth rates or longevity as well as allowing an out-of-range existence? The possibility, in all studies that reveal “‘gigantism,”’ that sampling artifact plays a role cannot be overlooked. It is easy to envision an artificial selection of larger spec- imens in any collection. Here, however, our collections were Over many years, and the “‘giants”’ included species that are considered uncommon in the region (e.g., Lyonsia hyalina, Chaetopleura apiculata). The extensive sam- pling Gn terms of number of individuals doing the sur- veys plus time allotments) would certainly have revealed larger populations of these species through time. In most cases, the specimens of a particular species, large or not, were only rarely collected. Smaller specimens of the same species were equally atypical in these communities. Along the opposite spectrum, Prezant (1979, 1981) re- ported a “‘dwarfed’’ population of Lyonsia hyalina from Nahant Bay, Massachusetts. This population was com- posed of significantly smaller individuals, averaging half or less the size of those from more southerly populations (e.g., Cape Cod). The exact reason for this smaller size was not determined; however, the Nahant population was consistently infected with dense populations of coccidia that almost occluded the proximal limbs of their kidneys. In this case, as opposed to the “‘gigantism’’ apparently induced by trematode-infected Hydrobia (Gorbushin, 1997), it is possible that a parasitic infestation reduced maximum growth attained. High seasonal primary productivity, coupled with the large array of protected natural and manmade habitats, offers conditions for a rich and stable food supply. The question then is, at least in part, not why a few species in this region have a few specimens that are large, but why the hundreds of other species lack these unusually The Veliger, Vol. 45, No. 4 large representatives and why so few within a population grow to unusually large sizes? Aside from the obvious ease with which the larger specimens are found, the an- swer probably rests with a few genetic anomalies con- fined within overall genetic constraints. Acknowledgments. This research was funded in part by Department of Interior, National Park Service Cooperative Agreement No. 400- 4-3007, “Inventory of Marine/Estuarine Benthic Invertebrate Com- munities, Assateague Island National Seashore, Maryland.” We es- pecially thank Carl Zimmerman of the National Park Service for his extensive support during this project. We gratefully acknowledge the tremendous field and/or laboratory efforts of Heather Bennett, Matthew Tieger, Matthew Foradori, Sonya Skoog, Andrew Reed, Michel Cupples, Brandon Repko, Janet Schultz, Justin Foley, Mat- thew Vasil, Alexis Gray, Paul Dolderer (all IUP students), Jack Ku- mer, Elaine Furbish, Michael Klensch, Sheila Pfalzer, Denise Ernst, Michele Juliano, Charles Oshaben, Sherrie Thomas, Scott Hoenin- ghausen, Rose Railey, Karen Rota, Brendan Williams, William Hus- lander, Phil Heckman, Cheryl Hightower, Allison Turner, Gary Lud- wig and Cyndi Smialek (all associated with the National Park Ser- vice). We also thank all the students of BI 481, Biology of Mollusks, taken at the Marine Science Consortium, Wallops Island, Virginia. Paula Mikkelsen kindly helped update our molluscan taxonomy. Our thanks to Barry Roth who helped make this a much better manu- script. 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Lindberg Department of Integrative Biology, University of California, Berkeley, California 94720, USA At the beginning of the last century the malacological world was privileged to have an array of distinguished practitioners. William H. Dall and Paul Bartsch at the Smithsonian Institution, Henry A. Pilsbry at the Academy of Natural Sciences in Philadelphia, Harold Heath at Stanford University, S. Stillman Berry in Redlands, Cal- ifornia, and numerous others led the way in describing the living and fossil molluscan fauna of North America. These workers ultimately described over 10,000 taxa, and their efforts capped what might be thought of as the “Golden Age’’ of American malacology. However, the most influential malacologist of the twentieth century would not be born for another 40 years. In contrast, he would describe only a handful of taxa in a career that spanned the last half of the century, but there is no de- nying the import of his contributions to the field of mal- acology and far beyond. Stephen Jay Gould was born on September 10, 1941, in Queens, New York. Like many students of natural his- tory his fascination with organisms began at an early age, and the dinosaur exhibit in the American Museum of Nat- ural History in New York was a favorite destination. Steve obtained his undergraduate degree in Geology at Antioch College, and went on to graduate work at Co- lumbia University, receiving his Ph.D. in 1967. However, the question he chose for his dissertation was not in deep time but rather in the shallow sand dunes of Bermuda. Steve had become fascinated by the diversity of land snails there and in the Bahamas and he sought to under- stand their insular evolutionary patterns. Papers on Poe- cilozonites and Cerion soon followed, many co-authored with David Woodruff. In 1984, Steve described his first two species—the Giant and Dwarf Smokestack Cerion (Cerion excelsior Gould, 1984a, and Cerion caminus Gould, 1984a, respectively). From his study of Bahaman land snails Steve noticed that morphological evolution in Poecilozonites was not gradual; rather, large changes appeared suddenly, and these morphological reorganizations were short lived in the fossil record and followed by another period of stasis. Another Columbia University graduate student had no- ticed a similar pattern in the diversification of trilobites, and after comparing notes they joined forces as Eldredge & Gould (1972) to unleash punctuated equilibrium on a paleontological world unaware of its reliance on a cloven hoof print of theory—gradualism. To be certain, the pres- ence of stasis in the fossil record had been noticed much earlier (e.g., Dall, 1877), but rather than eschew it as ar- tifact (or use it to argue against Darwinian evolution), Eldredge and Gould embraced it as the fossil signature of allopatric speciation and extended its implications into macroevolution theory. In 1977 Ontogeny and Phylogeny was published. This seminal volume recovered the baby that had been thrown out with Haeckel’s bathwater, and foreshadowed the re- surgence of the field of evolutionary development. It also had a profound influence on a cohort of graduate students who read the book in seminars across the country. Mol- luscan examples were scattered throughout the text, in- cluding Ockelman’s (1964) study of small insular bi- valves, Stanley’s (1972) progenetic transitions in bivalve habits, Hoagland’s (1975) dissertation work on life his- tory evolution in Crepidula, as well as Steve’s own work on Poecilozonites and Cerion. It is not surprising that mollusks also figured promi- nently as study organisms among Steve’s students. These students included Warren Allmon (1988) who investigat- ed heterochrony in the evolution of Turritella shell mor- phology, Dana Geary (1986) who studied a Late Miocene radiation of melanopsid gastropods, and Jane Rose (1990) who examined the relationship between ecology and var- iation in Cerion. Many of his students’ themes were fa- miliar, the relationships between ontogeny and phyloge- ny, and comparisons of punctuated vs. gradual patterns of diversification. Where necessary, there was a sophis- ticated array of statistical and multivariate analyses to quantify morphology and search for patterns through time. Steve often had an impressive multivariate meth- odology in his own work (e.g., Gould, 1967, 1970, 1984b) and his rigorous quantitative approach was mir- rored in the work of many of his students. It is also well known that Steve was not a “‘computer geek,’ and many obituaries have commented on his avoidance of word processors and POP3 compliant pro- grams. I also doubt that Steve ever navigated PAUP* or MacClade, but his own personal aversions never limited his students’ research programs; for example phylogenet- ic analyses were prominent in the work of Morris (1991) and Yacobucci (1999). Mollusks also served as exemplars in Steve’s column “This View of Life’’ that appeared in the pages of Nat- ural History Magazine. His commentaries dealt with nat- ural history issues that ranged from hens’ teeth to the dating of the beginning of the millennium; and mollusks often graced those pages as well. In fact, the story of an extinct little limpet once even found its way into a col- umn! However, the importance of those articles (and their Notes, Information & News Page 357 afterlives in collected volumes) should not be underesti- mated for they translated the esoteric reports of our re- search into popular pieces that have so far entertained and educated two generations of lay naturalists. Although Steve’s presence in the twenty-first century will be remembered as fleeting, this century will be marked by his greatest contribution, his magnum opus— The Structure of Evolutionary Theory (2002). Steve’s view of evolution as outlined in 1433 pages is (as it ever was) pluralistic and hieratical, and for that he took sub- stantial criticism from fundamental Darwinians and oth- ers (Morris, 2001). Steve’s ideas (as well as his prose) often exasperated some while inspiring others and this book is no different. David Wake (2002) has predicted that The Structure of Evolutionary Theory “*... will be a permanent factor in the struggle to understand how life has evolved.” Like Steve’s other writings, The Structure of Evolutionary Theory contains numerous molluscan ex- amples supporting his view of the history of life—from the punctuated evolutionary patterns of melanopsid spe- ciation to the spandrels of trochacean brooding. Steve Gould’s death on May 20, 2002, ended the career of the last century’s finest malacologist, but his legacy to malacology is immense. Steve never produced a classic monograph or performed cladistic analyses that spawned cascades of nomenclatural changes, and his name will appear as taxon author on only a few leaves on the tree of life. Nevertheless, his contribution to our field tran- scends all of these conventional measures. Steve showed us how mollusks could be used to unravel the patterns and processes of the last half a billion years of life, and when current theories and models failed to explain these patterns, Steve was not shy about proposing new ones. In fairness, Steve was not the only one to travel down this path. His cohort includes such eminent colleagues as Michael Ghiselin, Steve Stanley, and Geerat Vermeij— malacologists all—who have extended our collective vi- sion beyond the usual taxon-based questions and practic- es that we typically undertake. They took our (and their) favorite taxon and addressed a broad suite of evolutionary questions that provide insights into some of the processes that have shaped the history of life on earth, and they shuffle shells (and the shell-less) with the best of them. I observed Steve during a visit he made to Berkeley in 1988 move effortlessly through our Cerion holdings, sug- gesting mixed lots and re-identifying specimens. He also searched the vermetids for especially meandering speci- mens. Their openness intrigued him, rules were being broken, and the transition seemed to mark an important yet unknown event in both their ontogeny and phylogeny. He clearly understood and relished the value of museum collections and was just as accomplished there as he was penning an introduction to a research paper that would cast Achatinella as the devil’s advocate and the Rev. Gul- ick as Mephisto (Gould, 1971). One cannot help but notice the parallels between the turn of the last century and today. The malacological con- tributions and scope of work by Dall, Pilsbry, Berry, and others in the early 1900s were enormous and often viewed as insurmountable by later workers. Up until about 20 years ago, most American malacological polls would have undoubtedly chosen one of these gentlemen’s contributions as the most significant of the twentieth cen- tury. Today the work of Gould and others has shown us the potential of molluscan studies, and set new standards and expectations for modern malacological research. However, I doubt that Steve will vie for first place at the end of the current century. That spot will likely be re- served for a malacologist who has yet to undergo meiosis. We cannot predict where his or her future contributions may lie. I suspect that assembling the unfalsified Mollus- ca branch of the tree of life or determining the regulatory cascades of the key innovations in the diversification of the molluscan bauplan will certainly occur in the next 98 years. However, since we cannot know our future intel- lectual descent’s contingencies we have no way to predict the directions of that future research. Therefore we might as well just get on with the work before us—Steve would have it no other way. Literature Cited ALLMON, W. D. 1988. Evolution and environment in turritelline gastropods (Mesogastropoda, Turritellidae), lower Tertiary of the U.S. gulf and Atlantic coastal plains (United States). Ph.D. Dissertation, Harvard University. 826 pp. Da.i, W. H. 1877. On a provisional hypothesis of saltatory evo- lution. American Naturalist 11:135—137. ELprebceE, N. & S. J. GouLp. 1972. Punctuated equilibria: an alternative to phyletic gradualism. Pp. 82—115 in T. J. M. Schopf (ed.), Models in Paleobiology. Freeman, Cooper & Company: San Francisco. Geary, D. H. 1986. The evolutionary radiation of melanopsid gastropods in the Pannonian Basin (late Miocene, eastern Europe). Ph.D. Dissertation, Harvard University. 238 pp. GouLD, S. J. 1967. Evolutionary patterns in pelycosaurian rep- tiles: a factor-analytic study. Evolution 21:385—401. GouLp, S. J. 1970. Land snail communities and Pleistocene cli- mates in Bermuda: a multivariate analysis of microgastropod diversity. Proceedings of the North American Paleontologi- cal Convention, Part E:486—521. GouLp, S. J. 1971. Environmental control of form in land snails: a case of unusual precision. The Nautilus 84:86—93. GouLD, S. J. 1977. Ontogeny and Phylogeny. Harvard University Press: Cambridge, Massachusetts. 501 pp. GouLD, S. J. 1984a. Morphological channeling by structural con- straint: convergence in styles of dwarfing and gigantism in Cerion, with the description of two new fossil species and a report on the discovery of the largest Cerion. Paleobiology 10:172-194. GouLD, S. J. 1984b. Covariance sets and ordered geographic var- iation in Cerion from Aruba, Bonaire and Curacao: way of studying nonadaptation. Systematic Zoology 33:217—237. GouLp, S. J. 2002. The Structure of Evolutionary Theory. Har- vard University Press: Cambridge, Massachusetts. 1433 pp. HOAGLAND, E. 1975. Reproductive strategies and evolution in the Page 358 genus Crepidula (Gastropoda: Prosobranchia). Ph.D. Disser- tation, Harvard University. 360 pp. Morris, P. J. 1991. Functional morphology and phylogeny: an assessment of monophyly in the Kingdom Animalia and in Paleozoic nearly-planispiral snail-like molluscs. Ph.D. Dis- sertation, Harvard University. 435 pp. Morris, R. 2001. The Evolutionists: The Struggle for Darwin’s Soul. W. H. Freeman: New York. 262 pp. OCKELMAN, N. 1964. Turtonia minuta (Fabricius), a neotenous veneracean bivalve. Ophelia 1:121—146. Rose, J. A. 1990. Cerion on San Salvador, Bahamas: ecology and intraspecific variation. Ph.D. Dissertation, Harvard Uni- versity. 149 pp. STANLEY, S. M. 1972. Functional morphology and evolution of byssally attached bivalve mollusks. Journal of Paleontology 46:165-212. WAKE, D. B. 2002. A few words about evolution. Nature 416: 787-7188. Yacosuccl, M. M. 1999. The evolutionary radiation of acantho- ceratid ammonites in the Cenomanian western interior sea- way of North America. Ph.D. Dissertation, Harvard Univer- sity. 414 pp. Anatomical Description of Pisidium johnsoni E.A. Smith, 1882 (Bivalvia: Sphaeriidae) from Madagascar A. V. Korniushin National Museum of Natural History, B. Khmelnitsky str. 15, 01601 Kiev, Ukraine; akorn @carrier.kiev.ua and J. Gerber Department of Zoology, Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, Illinois 60605, USA; jgerber @ fieldmuseum.org Kuiper (1966) reported five species of the genus Pisidium C. Pfeiffer, 1821, from Madagascar, one of them [P. cas- ertanum (Poli, 1791)] being cosmopolitan, two (P. ovam- picum Ancey, 1890, and P. viridarium Kuiper, 1956) rep- resenting the African fauna, and two (P. johnsoni E.A. Smith, 1882, and P. betafoense Kuiper, 1953) being restrict- ed to the island. P. johnsoni was the most interesting among these species, since its similarity to the Holarctic P. milium (Held, 1836) was noted (Kuiper, 1966). However, no ana- tomical data on the species were available until now, where- as soft body characters have proved to be rather informative for the systematic and phylogenetic studies in Palearctic and African Sphaeriidae (Korniushin, 1998a, b). Recently, we examined a sample from Central Mada- gascar, now deposited in the Field Museum of Natural History, Chicago (FMNH), containing two Pisidium spe- cies. One of the species (FMNH 296603) was identified as P. viridarium, and its anatomical characters were in good agreement with those reported in the literature (Kor- niushin, 1998b). The other species (now FMNH 296604) The Veliger, Vol. 45, No. 4 appeared to be P. johnsoni, and a description of its anat- omy is provided below. The species identification was confirmed by comparison with the lectotype of P. john- soni deposited at the Natural History Museum, London (BMNH) and examined by the senior author in 1995. For comparison, materials from the collections of D. S. Brown (Pisidium ovampicum) and A.V. Korniushin (P. milium) were used. All samples were preserved in alcohol. Anatomical characters were observed under a stereomicroscope and drawn with a camera lucida. Gill and mantle preparations were processed according to Korniushin (1995). Below a description of the anatomical characters and a brief discussion of the possible relationships of the ex- amined species are provided. Pisidium johnsoni E.A. Smith, 1882 Material: Lectotype BMNH 82.3.5.23, 20 lieu (about 80 km) from Tananarivu, Madagascar; FMNH 296604, | km N of Ilempona, approx. 40 km NE of Antsirabe, Central Madagascar, in a shallow ditch along railroad tracks, leg. R. Webranitz 15 December 1989, 3 specimens. Shell characters (Figures 1A, B): Specimens FMNH 296604 corresponding with the published description (Kuiper, 1966) and the lectotype. Adductor muscles: Posterior adductor small, oval (Fig- ure 1C). Anterior adductor bean-shaped, markedly shifted upward (dorsally). Mantle: Mantle edge thickened by strong development of longitudinal muscles (Figures 1C, F). Presiphonal su- ture markedly elongated, longer than pedal slit. Inner ra- dial mantle muscles arranged in four strong and clearly defined bundles, three of them (anterior) placed at edge of pedal slit close to each other, posterior bundle at distal end of presiphonal suture. Gill: Outer demibranch placed at tenth filament of inner one (two specimens examined). Brood pouch in low po- sition (Figure 1D), formed by four filaments of inner de- mibranch and partly covered by the inner (ascending) la- mella. Three large larvae found in each of studied pouches. Nephridium: Open type (pericardial duct visible between branches of dorsal lobe), dorsal lobe quadrangular (Figure 1B). Remarks: The elongated presiphonal suture and very short pedal slit were noticeable also in the dried soft body of the lectotype (Figure 1G). Pisidium johnsoni has a very peculiar anatomy and is distinctly different from other species of Pisidium. How- ever, it is similar to the Holarctic P. milium (see Korni- ushin, 1996) in its very short pedal slit, in addition to the shell characters reported by Kuiper (1966). A similar anatomy was also reported for the Madagascar and Af- Notes, Information & News Page 359 Figure 1. A—F Shell and anatomy of Pisidium johnsoni from Madagascar (FMNH 296604). A. Lateral and frontal view of shell. B. Hinge (above—left valve, below—right valve). C. Gross anatomy. D. Gill from inner side. E. Dorsal view of nephridium. E Mantle edge from inner side. G. Lectotype of P. johnsoni (BMNH 82.3.5.23), mantle edge of dried soft body from outside. H. Pisidium ovampicum, South Africa, D. Brown collection, mantle edge from inner side. I. The same structure in Pisidium milium, Ukraine, A. Korniushin collection. Key: aa, anterior adductor; bp, brood pouch; c, cardinal teeth; ct, ctenidium; dg, digestive gland; dl, dorsal lobe: es, exhalant siphon; id, inner demibranch; is, inhalant siphon (opening); 1, lateral teeth; 1g, ligament; Ip, labial palps; mri, inner radial mantle muscles; n, nephridium; od, outer demibranch; pa, posterior adductor; pd, pericardial duct; ps, pedal slit; pss, presiphonal suture. Scale bars = | mm. rican species P. ovampicum (see Korniushin, 1998b). The three species under consideration share the following an- atomical characters: bean-shaped anterior adductor, mark- edly elongated presiphonal suture, concentrated inner ra- dial mantle muscles, and open type of nephridium. Pisi- dium johnsoni is unique in the strong development of its longitudinal mantle muscles, especially in the presiphonal suture. Pisidium milium differs from P. johnsoni in the lower placement of its anterior adductor, as well as in much more pronounced and more concentrated inner ra- Page 360 The Veliger, Vol. 45, No. 4 dial mantle muscles (Figure 11). Concerning the arrange- ment of muscle bundles, P. johnsoni is more similar to P. ovampicum than to P. milium (Figure 1H). Korniushin (1998a) suggested that an elongated presi- phonal suture and concentrated radial mantle muscles were apomorphic character states among species of Pis- idium. Also, the large bean-shaped adductor has not been observed in the other studied species of this genus. Thus, at least some of the similarities between the three dis- cussed species may be synapomorphies supporting their belonging to a separate clade within Pisidium. However, their relationships cannot be resolved now. Either P. mil- ium and P. johnsoni, or, under the assumption that the strong similarities of the latter two species are resulting from parallel evolution, P. ovampicum and P. johnsoni might be regarded as a pair of sister taxa. A phylogenetic analysis of the whole genus Pisidium is needed in order to support or reject these hypotheses. Literature Cited KorNIUSHIN, A. V. 1995. Anatomy of some pill clams from Af- rica, with the description of new taxa. Journal of Molluscan Studies 61:163-172. KORNIUSHIN, A. V. 1996. Bivalve Molluscs of the Superfamily Pisidioidea in the Palaearctic Region: Fauna, Systematics, Phylogeny. Schmalhausen Institute of Zoology: Kiev. 176 pp. [In Russian] KORNIUSHIN, A. V. 1998a. Evaluation of anatomical characters and their applicability for reconstructing phylogenetic rela- tionships in the Palearctic species of Pisidium s. 1. (Mollus- ca, Bivalvia). Vestnik Zoologii 32(1—2):88—97. KORNIUSHIN, A. V. 1998b. Anatomy of South African species of the genus Pisidium (Mollusca Bivalvia Sphaeriidae) and their taxonomic affinities. Journal of African Zoology 112(3):223—235. KuIPER, J. G. J. 1966. Les espéces africaines du genre Pisidium, leur synonymie et leur distribution (Mollusca, Lamellibran- chiata, Sphaeriidae). Annales du Musée royal de I’ Afrique Central, Sciences zoologiques 151:1—77. Notice to Veliger Contributors At its 2002 meeting, the Board of Directors of the Cali- fornia Malacozoological Society, Inc. voted to raise au- thors’ contributions to page costs. This measure is neces- sitated by economic considerations. The standard author’s contribution for manuscripts received in submission after July 31, 2002, will be US $50.00 per printed page. Pro- fessional biologists and others for whom publication in peer-reviewed journals such as The Veliger is normal in the course of their work are expected to contribute at this rate. 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R: GODDARD ANDINORAGR: FOSTER: s::c.-se---o0stseseses sss tscs steeesse state se 3/2)! Mollusca of Assateague Island, Maryland and Virginia: additions to the fauna, range exten- sions, and gigantism y ROBERT S. PREZANT, CLEMENT L. Counrts, III, AND ERIC J. CHAPMAN ....csccscsessecessseeseseee 3)ai NOTES, INFORMATION & NEWS The century’s finest DAVID: RE MINDBERG ii.ccseeeces dees oseueoeseteesiicds ces chccscence ce Sea dee oec eee Ese eae ona 356 Anatomical description of Pisidium johnsoni E. A. Smith, 1882 (Bivalvia: Sphaertidae) from Madagascar A. V. KORNIUSHIN AND'J.. 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