fit
>• I I I f* »1^ -t- #- t- t * .■?»' .
I f I 4 )
rr#*j
rfr-ffc
%'mm^^^-
^^*^
j^ #. ^- m ^. .^. Sr ik W: ^ t k-' Ik 1^ i^ »^^ i" 1^ i» ft*' !^ "^^ 1
« lit % ^ ^ ^
^^Vl.**^^
•':j*^.i^ y..* i^.#f''
r m mm ^^i^^^ ^ ^ # J
.1 A m- .^ .i^
An
* #■ 'jl' >■
'.v,'>X-\'.-i
tP T' r
'm^-wtrwi
i:»_*
jf-'
f > *■ « fr » * * *■ f- * ♦' * 9" 9- ^ '■
>v*v
*V**»*»*f'>%*»*VW^
HOI
FHE NAUTILUS
Volume 104 1990
AUTHOR INDEX
Annis. C G , Jr. Belancer, T. V.
Bcx;an, a. E
Cairns. J , Jr., . . .
Cherrv, D. S
Coney. C. C
doherty, f. g. Emberton. K. C. Emerson. V\'. K P'airbanks. H. L
CilLMER, R \\
Harasewych. M. G. houbrick, r. s.
Hl'NTER. R D. ...
. 4 Lodge. DM
4 Marshall, B ,\
29 McLean, J. li
10 Neck, R. W
10 Petuch, E. J 5'
130 Pierce, H. G
10 Richardson, L
■W Robertson, R
108 Rosenberg, G,
71 Sage, W E. Ill 1,
1 1 1 Spamer, E. E
120 Stahl, T
3.5 Toll, R B
87 VanEpps, D. D
92
10,3
I i
16
, 96 53 33
145 29
108 29 92 26
. 4
NEW TAXA proposed IN VOLUME 104 (1990)
MONOPLACOPHORA
Micropilina tangaroa Marsli.ill, new .species 107
GASTROPODA
Cvathermiidae McLean, new family (Archeogastropoda) 78
Stjmmetrophalus McLean, new genus ((\!yallierniiidae) 79
Symmctrophalus regitlaris McLean, new Species (Cyathermiidae) 79
Turritella tiiarianopsis Petuch, new species (Turitellidae) 59
Cypraea (Macrocypraea) spengleri Petuch, new Species (Cypraeidae) 97
Cypraea (Pseiidozonaria) porteUi Petuch, new species (Cypraeidae) 97
Chicoreus hilli Petuch. new species (Muricidae) 59
Dermomurex (TrialatcUa) cuna Petuch, new species (Muricidae) 60
Murt'X ruhitlus fxinuniicits Petuch, new species (Muricidae) 62
Mtirexiella eduardpauli Petuch, new species (Muricidae) 62
Miccosukea Petuch. new subgenus (Melongenidae) 99
Melongena (Miccosukea) cynthiac Petuch. new species (Melongenidae) 99
Melongena (Miccosukea) holeylandica Petuch, new species (Melongenidae) 100
Latirus cuna Petuch, new species (Fasciolariidae) 62
Latirus deynzcrorum Emerson and Sage, new species (Fasciolariidae) 1
Milra (Sehularia) leonardi Petuch. new species (Mitridae) 63
Ohta (Strepliona) reticularis erncsti Petuch. new species (Oiividae) 63
Prunum leonardhilli Petuch. new species (Margineiiidae) 63
Falsilyria ernensti Petuch. new species (V'oi\itidae) 64
Sraphella seminolc Petuch. new species (Volutidae) 100
Voluta lacertina Petuch. new species (Volutidae) 64
Conux brunneufilaris Petuch, new species (Conidae) 66
Conus capeletii Petuch, new species (Conidae) 100
Conus ernesli Petuch, new species (Conidae) 67
Conus granarius panamicus Petuch, new species (Conidae) 67
Conus griffini Petuch, new species (Conidae) 103
Conus hilli Petuch, new species (Conidae) 67
Conus lemoni Petuch, new species (Conidae) 103
Conm roscmarijae Petuch. new species (C^onidae) 68
Fusiturrictda sunderlandi Petuch, new species (Turridae) 69
Knejastia hilli Pclucli tii\.. species (Turridae) 70
Procijmhulia phillporum Gilmer, new species (Peraclididae) 112
BIVALVIA
Bellascinlillii Coney ii'"' <p.'cies (Galeommatidae) 137
Bellascintilln parmaUr,. n f miey. new species (Galeommatidae) 138
THE NAUTILUS
Volume 104, Number 1 June 25, 1990 ISSN 0028-1344
A quarterly devoted to malacology.
iAdU^^i Biological Laboralcr^ LIBRARY
JUL 9 1990
j Woods Hole, Mass.
EDITOR-IN-CHIEF Dr. M G. Harasewych Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
ASSOCIATE EDITOR Dr. R. Tucker Abbott American Malacologists, Inc. P.O. Box 2255 Melbourne, FL 32902
CONSULTING EDITORS Dr. Riidiger Bieler Department of Malacology Delaware Museum of Natural History P.O. Box 3937 Wilmington, DE 19807
Dr. Robert T. Dillon, Jr. Department of Biology College of Charleston Charleston, SC 29424
Dr. William K. Emerson
Department of Living Invertebrates
The American Museum of Natural
History
New York, NY 10024
Mr. Samuel L. H. Fuller 1053 Mapleton Avenue Suffielcl, CT 06078
Dr. Robert Hershler Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
Dr Richard S. Houbrick Division of Mollusks National Museum of Natural History Smithsonian Institution Washington. DC 20560
Mr. Richard I. Johnson Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, OH 43210
Dr. James H. McLean Department of Malacology Los Angeles County Museum of Natural History 900 Exposition Boulevard Los Angeles, CA 90007
Dr. Arthur S. Merrill % Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Ms. Paula M. Mikkelsen Harbor Branch Oceanographic Institution, Inc. Ft. Pierce, FL 33450
Dr. Donald R. Moore
Division of Marine Geology
and Geophysics
Rosenstiel School of Marine and
Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149
Mr. Richard E. Petit
P.O. Box 30
North Myrtle Beach, SC 29582
Dr. Edward J. Petuch Department of Geology Florida Atlantic University Boca Raton, FL 33431
Dr. David H. Stansbery Museum of Zoology The Ohio State Universit\ Columbus, OH 43210
Dr. Ruth D. Turner Department of Mollusks Museum of (Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Geerat J. Vermeij Department of Geology University of California at Davis Davis, CA 95616
SUBSCRIPTION INFORMATION
The subscription rate per vohmie is US $25.00 for individuals, US $35.00 for institutions. Postage outside the United States is an additional US $4.00 for surface and US $12.00 for air mail. All orders should be accompanied by payment and sent to: THE NAUTILUS, P.O. Box 3430, Silver Spring, Ml) 20901.
Change of address: Please inform the publisher of your new address al least 6 weeks in advance. All conununications should include both old and new addresses (with zip codes) and state the effective date.
THE NAUTILUS (ISSN 0028- 1344) is published quarterly by Trophon Corporation, 8911 Alton Parkway, Silver Spring, MD 20910.
Second Cla.ss postage paid at Silver Spring, MD and additional mailing offices.
POSTMASTER: Send address changes to: THE NAUTILUS P.O. Box 3430 Silver Spring, MD 20901
TH Ef^NAUTI LUS
CONTENTS
Volume 104, Number 1
June 25. 1990
ISSN 0028-1344
William K. Emerson Walter E. Sage, III
A new species of Latirua from the Philippine Islands (Gastropoda: Fasciolariidae)
T^t::
Thomas V. Belanger Growth rates of the Asiatic Clam, Corhicula fluminea, in \
Clifford G. Annis, Jr. the Upper and Middle St. Johns River, Florida J(JL 9 1990 ^
Delmar D. VanEpps 1
' ',
Francis G. Doherty Multiseasonal tissue growth trends in Corhicula fluminea
Donald S. Cherry (Bivalvia: Corbiculidae) from the New River, Virginia 10
John Cairns, Jr.
Raymond W. INeck Geological substrate and human impact as influences on
bivalves of Lake Lewisville, Trinity River, Texas 16
Ronald B. Toll A reaffirmation of the nomenclatural status of Octopus
filosus Howell, 1868, the senior synonym of Octopus Inimmclincki Adam, 1936 26
Gary Rosenberg Coelatura Conrad, 1853, Caelatura Conrad, 1865 and
Arthur E. Bogan Coelatura Pfeiffer, 1877 (Mollusca): a tale of two
Earle E. Spamer diphthongs 29
Kenneth C. Emberton Eduardus Pilsbry, 1930, a subgenus of Praticolella
Leonard Richardson Martens, 1892 (Gastropoda: Stylommatophora:
Polygyridae) 33
INews and Notices 34
WESTERN SOCIETY OF MALACOLOGISTS
in conjunction with the
SANTA BARBARA SHELL CLUB
is offering a
STUDENT RESEARCH GRANT IN MALACOLOGY
As part of their commitment to the continued study of molkisks, tlie Western Society of Malacologists and the Santa Barbara Shell (^lub are pleased to announce the availability of grants to support student research in malacolog\ . Funds are available for actual research costs, including iiut not limited to, field and laboratory equipment, chemicals, photographic supplies, computer time and supplies, microscope usage fees, and reasonable research travel costs.
ELIGIBILITY
Applicant must be a full time student in a formal graduate or undergraduate degree program.
The thesis, di.ssertation or research project must be focused primarily on the systematics, biology, ecology or paleontology of marine, terrestrial or freshwater mollusks. Research currently in progress or beginning in the 1990- 91 academic year w ill be considered.
REQUIREMENTS
Five copies of the following ilocuments are required for each application:
1. A completed application form.
2. A proposal, limited to two pages, which discusses the research project and its malacological significance including details of the work to be aided by this grant.
3. A budget which outlines how the grant funds will be used.
4. A resume or outline of the applicant's academic background.
5. A letter of recommendation from the applicants research advisor.
6. A list of grants and amounts which are currently being received or have been applied for the 1990- 91 academic year.
AWARD
One or more research grants up to $1,500 are available.
APPLICATION DEADLINE
Completed applications musi be received no later than .'J I July 1990. .Awards will be announced by 15 S(^ptember 1990. Plea.se send applications to:
Malacology Grant
Department of Invertebrate Zoology
Santa Barbara Museum of Natural History
2559 Puesta del Sol Road
Santa Barbara, CA 93105
For further information or applications contact:
Dr. Vida Kenk (408) 924-4894, or Paul Scott (805) 682-4711
THE NAUTILUS 104(l):l-3. 1990
Page 1
A New Species of Latirus from the Philippine Islands (Gastropoda: Fasciolariidae)
William K. Emerson Waller E. Sage, III
Department (if Iinertebrates American Museum of Natural Histors Ne« York, NY 1002-1, USA
ABSTRACT
Latirus deynzcrorum new species is descril^ed from specimens obtained in tangle nets set off Bogo, NE Cebu Island, Philippine Islands and elsew here in the central Philippine Archipelago.
INTRODL'CTION
During the past ten years many new species or otherwise significant specimens of marine mollusks have Ijeen col- lected by fishermen from tangle nets set in moderateK' deep water in the channels off the central Philippine Islands, mostK in the region of Cebu and Bohol. Speci- mens of the new species of Latirus described herein were obtained several years ago from these sources by Major Al Deynzer of Showcase Shells, Sanibel, Florida, who recently submitted the specimens for study. We take pleasure in describing this nev\' ta.xon in honor of Bev and Al De>nzer, \\ ho, as avid students of mollusks, have generously shared their discoveries with us and others through the years.
SYSTEMATIC ACCOUNT
Family Fasciolariidae Gray, 1847 Subfamily Peristerniinae Tryon, 1880 Genus Latirus Montfort, 1810
Type species: by monotypy, Latirus aurantiacus Mont- fort, 1810 [= L. gihhulus [QmeWn. 1791)], Recent, Indo- Pacific,
Latirus deijnzerorurn new species
(figures 1-3)
"Latirus sp. Springsteen, 1985:4,
■, fig. 4.
Diagnosis: A mediimi-size latirid, ornamenteil with prickled varices. Shell somewhat resembles Latirus mac- ulata (Reeve, 1847; Turbinclla species 70, pi. 13:70a, 70b) from the Indo-Pacific (Springsteen & Leobrera, 1986: 181, pi. 48:22). It differs from Reeves taxon in having a
larger, more angular shell, with a much longer and more recurved siphonal canal and by distinctive sculptural characters and color patterns, Peristernia cremnochione Melvill (1891:397, pi. 2:9), a smaller species attaining 24 mm in length, from Mauritius, more closely resembles this new taxon in the outline and color pattern of the shell. Melvill's taxon, however, lacks a siphonal fascicle, and has a short, straight siphonal canal, characteristic of Peristernia.
Description: Shell solid, fusiformly elongate, attaining 40-1- iTim in length, whorls angularK rounded, axialh ribbed and crossed by conspicuous spiral lirae forming small prickle-like profusions medially on varices, si- phonal canal narrowly elongated and recurved, outer lip thin, edge of labrum lirate.
Protoconch glossy, smooth, consisting of 1 Vz embryonic whorls; postnuclear whorls 6 to 6'/2 in number, with 8 to 9 widely spaced, rounded axial ribs, crossed by about 14 strong spiral cords on the body whorl posterior to the siphonal canal. Suture partialK obscuretl b\ fluted axial riblets. Dorsal surface of siphonal canal with 2 prominent spiral ridges and numerous lesser intervening lirae. Ap- erture widely ovate, outer lip with weak lirations; col- umella smooth, with inner margin raised to form a thin detached edge anteriorly, extending to near the terminal end of the narrow, recurved siphonal canal; siphonal fascicle well-formed and strongly corded. For measure- ments, see table 1. Radula and soft parts not seen.
Color: Protoconch light tan; base color of shell orange buff, early whorls of spire grayish brown, subsequent whorls with broken bands of brown forming prominent blotches (figure 1); some specitnens weakK blotched or entirely lacking blotches (figures 2, 3); fascicle stained dark brow n above and w ithin the groove; aperture pink- ish white.
Type locality: Off Bogo, NE Cebu Island (11°03'N, 124°E), from tangle nets set in moderateK deep water. May, 1981.
Type depository: Holotype AMNH 232138, 4 paratypes AMNH 232139; 2 paratypes in the Deynzer collection.
Page 2
THE NAUTILUS, Vol, 104, No. 1
Figures 1-3.
X 1V4.
Type specimens of Latirus deynzerorum new species. 1. Holotype AMNH 232138; 2, 3. Paratypes AMNH 232139;
Range: Known from the type locality in the central Philippine Islands; also off Panglao Island (9°35'N, 123°48'E), October, 1985, in "deep water," tangle nets, AMNH 239585 (2 specimens, ex-F. J. Springsteen coll.); and off Punta Engano, Mactan Island, NE Cebu, in tangle nets (Springsteen, 1985:4).
Remarks: Our knowledge of the ta.xonomic relation- ships of the multitude of latirid-like species that are re- ferable to Peristerniinae genus-group taxa has not pro- gressed much since the appearance of the early reviews of Kiener (1840), KiJster and Kobelt (1844-1876), Reeve (1847), Tryon (1880, 1881), Cossmann (1889) and Melvill (1891, 1911). At the present time (see Boss, 1982:1016, 1017; Vaught, 1989:50), most of these species are assigned to either the genus Latirus scnsu tato (with several non- nominate subgenera), or to the genus Peristernia Mcirch (1852:99), type species (by subsequent designation: Coss- mann 1889:166), Turhinella crenulata Reeve (1847, pi.
4, fig. 24). Based on shell characters alone, however, generic placement of these species is largely arbitrary, without knowledge of the radular morphology. For ex- ample, the type of Fu.solatinis Kuroda and Habe (1971: 182), Fusolatirus pilsbryi (Kuroda and Habe, 1971:183, pi. 50, figs. 1, 2), was described as having '". . . the shell of Latiriis-form and the radula of Peristernia-{onnu\a.." Therefore, the precise generic allocation of the new species described herein must remain provisional until the nature of the radula is known.
ACKNOWLEDGEMENTS
In addition to Major Deynzer, we thank F. J. Springsteen for contributing comparative material. We also thank Andrew S. Modell and Stephanie Crooms of the Amer- ican Museum of Natural History, respectiveK , for the photography and word-processing.
Table 1. Latirus deynzerorum new species. Shell measure- ments of specimens in mm and number of postiiuciear whorls; widths measured including varices, n = 9. Specimens deposited in the AMNH collection unless otherwise stated.
|
No. |
||||
|
Length |
Width |
whorls |
||
|
Holotype (figure 1) |
39.6 |
17.3 |
6'/2 |
|
|
Paratype (figure 2) |
39.4 |
16.4 |
Wz |
|
|
Paral)pe (figure 3) |
33.4 |
15.3 |
6 |
|
|
Paratype (Deynzer |
L'Oll.) |
34.2 |
15.7 |
6 |
|
Paratype (De\nzer |
L-Oll.) |
33.9 |
15.0 |
6 |
|
Paratype |
31.0 |
14.4 |
6 |
|
|
Paratype |
27.2 |
12.8 |
6 |
|
|
Referred specimens |
■>.5..5 |
16.1 |
6'/2 |
|
|
(AMNH 2.39.58.51 |
■■A :} |
13.3 |
6 |
LITERATURE CITED
Boss. K. J. 1982. Mollusca. In: Parker, S. P. (ed.). S>nopsis and classification of living organisms. McGraw-Hill Book Company, New York, 1:945-1166.
Cossmann, M. 1889. Catalogue illustre des coquilles fossiles de I Eocene des environs de Paris. .Annales de la Societe Royale Malacologiqvie de Belgique, Memoires 24(4):3-381.
Gtnelin, J. E. 1791. Caroli a Linne Systema naturae per regna
tria naturae, 13th ed. Leipzig, vol. 1, pt. 6, cl. 6, \'ernies,
p. 3021-3910 Gray, J. E. 1847. .\ list of the genera of Recent Mollusca,
their synonyma and tvpes. Proceedings Zoological Society
of London.'for 1847:129-219. Kiener, L. C. 1840. Genre Turhinelle, Species general et icon-
ographie des cotjuilles \i\ antes. . . , Paris, 5:1-50. pis. 1-
21.
W. K. Emerson and W. E. Sage, III, 1990
Page 3
Kuroda, T. and T HuIk-. 1971 Iii: kuioda. T., T. llalw and K. Oyama (eds. ). The sea sliells ot Sagami Bay, collected by HLs Majest)' The Emperor ol Japan. Marnzen C^o,, To- kyo, p. i-xix, 1-741. Tokyo, p. \vi + 748 [Japanese text]; 121 pis., p. 1-489 [English text], p. 1-51 [index].
Kiister, H C. and \V. Kobelt. 1844-1876. Systematisches Con- chylien-Cabinet von Martini und Chemnitz, neu heraus- gegeben Turhinella und Fasciularia. . . . Nuremberg, 3(3a): 1-164.
Melvill, J. C;. 1891. .An historical account of the genus Ldtinis (Monttort) and its dependencies, with ilescriptions of elev- en new species, and a catalogue ot Latirus and FeristcnUa. Memoirs and Proceedings of the Manchester Literary & Philosophical Societ)', series 4, 4(5):365-411.
Melvill, J. C. 1911. An enumeration of the additions made to the genus Latirus Montfort, since 1891, with descriptions of three new species. The Journal of Conchologv 13(6): 164-178.
Moiitlnrt, P. D, dc 1810. t:onch\ liiilogic s\slematique et classilication methodique des ciHiuilles, . . Paris 2:1-676.
Morch, O. A. L. 1852. C;atalogus conchyliorum quae reliquit D .Alphonso D'Aguirra et (ladea CJomes de Yoldi. Typis Ludosici Kleini, Fasciculus Primus, C^openhagen, [Gastro- poda, etc.], 170 p.
Reeve, L. A. 1847. Conchologia Iconica: illustrations of the shells of Molluscous animals, vol. 4. Monograph of the genus Turhinella, text & 13 pis.
Springsteen, V. J. 1985. Some unusual I'hilippine shells, pt. 111. Carfel Philippine Shell News 7(4):3-7.
Springsteen, F. J. and F. M. Leobrera. 1986. Shells of the Philippines. Carfel .Seashell Museum. Manila, 377 p., illus.
Trvon, G. V\'., Jr. 1880, 1881. Family Fusidae, Manual of Conchology, series 1, 3(9):46-64, [issued, Jan. 2, 1880]; 3(10):65-97 [issued. Mar. 28, 1881].
Naught, K. C. 1989. A classification of the living Mollusca. American Malacologists, Melbourne. FL. \ii + 195 pp.
THF NAUTILUS 104(l):4-9, 1990
Page 4
Growth Rates of the Asiatic Clam, Corhicula fluminea, in the Upper and Middle St. Johns River, Florida
Thomas V. Bclanger Clifford G. Aniiis, Jr. Delmar D. VanEpps
Departnieiit of (^licinical and Em iroiiinental Knginecriiig Florida Institute of Tecfinology Melbourne, FL 32901, USA
ABSTRACT
Growth rates and population densities of Corhicula jiuminca were studied over a two year period in the Upper and Middle St. Johns River, Florida Measured grow th rates were compared with published data from other systems, and factors influencing growth rates were identified. Growth rates of C. fluminea were affected by flow rate and sediment type, and ranged between 0.0043 and 0.0437 mm/day in this study. Corlncula were found to dominate the sandy sediment regions, usually characterized by higher flow rates, while unionid mussels inhabited the more flocculent organic sediments present in slower moving water. Of the 1,6.50 bivalves collected from dredge samples, 79.3% were C. fluminea and 20.7/'; were unionids. Unionid growth was adversely affected by the presence of Corlncula. as mussel growth rates decreased when numbers of C. fluminea in- creased.
INTRODUCTION
Corhicula fluminea (Miiiler, 1774) has spread rapidly throughout the United State.s and has become a species new to many freshwater systems throughout the country (McMahon, 1982). It appears that the great success of C. fluminea is primarily due to its lack of predators, resis- tance to environmental stresses, tolerance of many sub- strates, high reproductive ability, rapid growth, and abil- ity to filter large volumes of water (McMahon, 1977; Mattice, 1979; Graney et al, 1980; Rodgers et ai, 1980; Gottfried & Osbourne, 1982). Population density and growth rate data from various aquatic systems have been well documented (Gardner et ai, 1976; O'Kane, 1976; Sickel, 1976; Britton et al., 1979; Kng, 1979; Buttner & Ileidinger, 1980; Scott-Waslik et ai, 1983; Welch & Joy, 19>-;4; Joy, 1985).
Mtfioiigh macroinvertebrate surveys noting the pres- '•ula fluminea were conducted in the Upper S! cr by Mascjn and Beianger (1979), Biizzi
(1979) '.ox ai.'.l Moody (1980) and Llibre (1982), little is known about the population dynamics and growth rates of the clams in tjiis river system. The purpose of
this research was to determine population densities, dis- tributions, and growth rates of C. fluminea in the I'pper and Middle St. Johns River so that comparisons with other aquatic systems could be made and possible factors in- fluencing growth rates could be identified. A secondary purpose was to investigate the effect of C. fluminea on the growth of indigenous unionid bivalves.
STUDY AREA
The St. Johns River basin encompasses 18,290 sq. km and is one of the few large rivers in the world that flows from south to north. The river originates in the dense marshes of St. Lucie County and flows approximately 300 km north to the Atlantic Ocean, east of Jacksonville, Florida. The topography of the study region is relatively flat, resulting in a shallow river-lake system. This study considered the upper and middle sections, with sampling sites extending from Zig-Zag Canal, Brevard County, to Lake Monroe, Seminole County (figure 1).
MATERIALS AND METHODS
Clams were collected at all sites from August 1983 through May 1984. Caged clams were maintained in the field during three separate periods, September 1983 to July 1984, August 1984 to February 1985, and February 1985 to July 1985. Each clam was measured to the nearest 0.05 mm for length (greatest anterior-posterior distance), width (greatest distance through the valves), and height (gre^itest dorso-ventral distance perpendicular to the the hinge line), using vernier calipers. Clams were measured before being placed in the cages and after retrieval. C^ages were constructed from 19-liter plastic buckets and approximately 100 holes 1 cm in diameter were drilled in the sides of each container. The bottom of each cage was filled with acid-waslied .sand to a depth of 25 cm and the cage fitted with a locked lid. Ten (first and second study periods) to 15 clams (third study period) were placed in each cage. In addition, five cages were placed
T. V. Belanger et ai. 1990
Page 5
R 60 Ver o Beoch
lor Ida ur npike
Figuro 1. Thf St Johns River hasin with Ideation of sampling sites. 1 = Zig-Zag Canal*; 2 = Lake Sawgrass Outlet; 3 = Camp Holly (Route 192)**; -4 = Lake Washington; 5 = Lake Wash- ington Outlet**; 6 = Lake Poinsett Outlet; 7 = Route 50 Bridge; 8 = Lake Harne> Inlet Bridge; 9 = Lake Harney Outlet; 10 = Lake Jessup Outlet, 11 = Lake Monroe Inlet*; 12 = Lake Monroe Outlet*; 13 = Lake Monroe Power Plant Outfall; * = sampling and cage site; ** = cage site only.
at the Lake Washington site to determine the effect of Corbicula fluminea populations upon the growth rates of unionid mussels. In this experiment, ten unionid mus- sels (Elliptio sp.) were placed in each cage together with C. fluminea in densities equivalent to 500, 1,000, 2,000 or 3,000 clams/m^. After five months, the unionid mus- sels were retrieved and measured to determine growth rates. Water quality parameters (depth, dissolved oxygen [D.O.], water temperature, flow rate, pH, and percent sediment volatile solids) were measured routinely (at least bimonthly) using standard techniques (A. PH. A., 1980). The mean values for these parameters at the sites are presented in table 1.
RESULTS AND DISCUSSION
Population Density and Distribution
Population densities of Corbicula fluminea varied widely along the St. Johns River system. Of the 1 1 sites sampled, only one site (Site 12) was completely devoid of clams. With the exception of the Lake Jessup site (Site 10), clams were found in densities greater than 100/m- at least once
Table 1. Mean plusical and chemical data from routine sam- pling at selected sites in the Upper and Middle St. Johns River. Data were collected at least bimonthK from August 1983 through May 1984.
|
Sedi- |
|||||||
|
ment |
|||||||
|
Flow |
vol. |
||||||
|
Depth |
DO* |
Temp* |
rate* |
solids |
|||
|
Site |
(m) |
(mg/l) |
CC) |
(ft/sec) |
pH |
(%) |
|
|
1 |
2.9 |
3.0 |
20.0 |
0.09 |
6.69 |
13.72 |
|
|
c |
2 |
2.0 |
4.7 |
21 0 |
0 20 |
7.19 |
18.20 |
|
:an |
-4 |
1.5 |
5.6 |
23.0 |
001 |
7.70 |
3.34 |
|
b |
2.5 |
6.1 |
22.0 |
0.30 |
7.42 |
2.00 |
|
|
1 |
7 |
3 4 |
4.9 |
22.0 |
0 19 |
7.04 |
4.73 |
|
8 |
2.6 |
5.3 |
20.7 |
0.47 |
724 |
2.13 |
|
|
9 |
2.7 |
8.0 |
19.5 |
0.29 |
7.71 |
7.35 |
|
|
10 |
2.4 |
8.2 |
20.4 |
0.20 |
8.74 |
3.70 |
|
|
11 |
4.3 |
5.7 |
23.2 |
0 39 |
7.88 |
474 |
|
|
12 |
44 |
5.8 |
24.3 |
0.16 |
8.23 |
11.42 |
|
|
13 |
4(1 |
5 5 |
20 9 |
0.17 |
8.30 |
3.14 |
Measured near sediment-water column interface.
during the nine sampling events. Four sites contained densities greater than 1,000/m-, with Lake Harney Inlet (Site 8) exhibiting the maximum density of 2,700 indi- viduals/m- in November, 1984. Table 2 lists the popu- lation densities of C. fluminea recorded throughout the study. Only juveniles were found in Zig-Zag Canal (Site 1), where they did not become established.
When only adult populations are considered, some generalities may be draw n from the data. Corbicula flu- minea were most abundant in sandy sediment with low organic content, such as the Lake Harney Inlet site (Site 8), where the highest mean monthly density of 839 clams/ m- was recorded. Sandy substrates were favorable for C. fluminea growth from Lake Washington (Site 4) down- stream to the Lake Harney Inlet (Site 8), and clams from
100
80--
o 60--
40
20
0
Total: 1,268 clams
1 2 4 6 7 8 9 10 11 12 13
Figure 2. Corhiciila fluminea population distributions, at the Upper and Middle St. Johns River sampling sites, 1983-84. (% frequencN = Corbicula percentage of total collected inverte- brates at each site; dotted line = only juvenile clams)
Page 6
THE NAUTILUS, Vol. 104. No. 1
Table 2. Carbicula fluminca population densities (no 'm^'), from sanipliriK .sites in tlie Upper and Middle St Johns Hi\er (.August 1983-Mav 1984)
198:5
1984
|
Site |
Aug |
Sep |
Oct |
Nov |
Jan |
Feb |
Mar |
.Apr |
May |
Mean |
SD |
|
1 |
|
|
*1.417 |
*233 |
*250 |
— |
— |
— |
— |
*211 |
464 |
|
2 |
|
— |
33 |
— |
150 |
— |
— |
— |
— |
20 |
50 |
|
4 |
600 |
567 |
217 |
117 |
217 |
17 |
67 |
433 |
17 |
250 |
229 |
|
6 |
183 |
67 |
33 |
117 |
700 |
383 |
583 |
— |
— |
230 |
263 |
|
7 |
200 |
283 |
117 |
117 |
433 |
517 |
1,033 |
183 |
217 |
344 |
292 |
|
8 |
|
— |
2,217 |
2,700 |
233 |
17 |
2,217 |
167 |
— |
839 |
1,166 |
|
9 |
|
— |
— |
— |
— |
17 |
17 |
— |
100 |
15 |
33 |
|
10 |
|
33 |
— |
17 |
17 |
— |
— |
— |
— |
7 |
12 |
|
11 |
117 |
367 |
267 |
— |
— |
— |
— |
— |
— |
188 |
162 |
|
12 |
— |
— |
— |
— |
NS |
NS |
NS |
NS |
NS |
— |
— |
|
13 |
NS |
NS |
NS |
NS |
— |
783 |
1,083 |
50 |
1,217 |
627 |
572 |
|
* — Ju\cni |
le elanis |
onl\. |
|||||||||
|
NS — Not sampled. |
these sites represented 68% of the total clams collected. Helanger et al. (1985) reported similar results and sug- gested that rivers with fine, well-oxygenated sand sub- strates would be optimal for the establishment of C. fluminca populations in newly colonized sites.
The distribution ol C. fluniinea in the Llpper and Middle St. Johns River (figure 2) is primarily related to sedinu'iit t\ pe and flow rate. The distribution of C. flii- minea varied from 34.2% of the total fauna at the Lake Harney Inlet site (Site 8) toO% at the Lake Monroe Outlet site (Site 12), where deep deposits of organic sediment occurred. Also, few clams were observed in the upper reaches of the study area (Sites I and 2), as peat sedi- ments, low flow rates and low dissolved o.xygen conditions predominated.
.\lthough it was found that both sediment type and Dow rate affected the density of C. fluminea populations, results from this study indicated sediment type was the most important limiting factor, as high flow can be in- effective if the sediment type is imsuitable. For example, samples taken from organic muck and peat .sediments
revealed only small numbers of C. fluminea. even though flow rate was often suitable. The reverse situation, sandy sediment and no flow, was encountered at the Lake Washington site (Site 4) where an average clam density of 250/m- was found. Flow rate is an important factor because it is responsible, in part, for the transport of essential materials to the clams, such as food and oxygen. It is also important for the dispersal of waste products and clam larvae. However, it appears that a very high flow rate can limit C. fluminca. At Camp Holly, ap- proximately 1 km upstream of the Lake Washington site, the flow rate averaged 1.0 ft/sec over sandy substrate during sampling trips but no clams were found. Obser- vations using SCL'BA revealed that the high current had .scoured the sediment surface, exposing hard-packed sand. Under these sediment and flow conditions it is very dif- ficult for clam larvae to become established in the river- bed. Instead, they are generally swept downstream to sites where the current velocity has decreased, enabling them to settle out. The natural spread of C. fluminea is limited bv the nonswimming larval stage, thus river cur-
|
Table 3. |
Elliptio sp. population density (no. nr) at tlie sanipl |
ling sites, 1983-84. |
||||
|
1 ^)8.> |
1984 |
Mean |
||||
|
Site |
Aug Sep Oct Nov Jan |
Feb Mar |
Apr |
May |
SD |
2 4 6
i
S
•I
10
1 1
12
1)
100
\i
*4,866
\S
* — Juvenile cLiiiit- ur.l\ NS— Not sampled
|
67 |
133 |
|
50 |
17 |
|
17 |
17 |
|
17 |
— |
NS
50
NS
67
17
17 50
33
NS NS NS
NS
NS
|
\541 |
1,622 |
|
41 |
52 |
|
19 |
21 |
|
4 |
8 |
|
2 |
6 |
|
2 |
6 |
|
6 |
17 |
T. V. Belanger et at., 1990
Page 7
rent can be an important dispersal mechanism leading to rapid down-river range expansion (McMahon, 1982). Corbictila fltiminea population densities in the St. Johns River are intermediate to the ranges reported in other areas of the United States. Hall (19(S4) reported densities as high as 6,663 clams/m- in the littoral zone of Lake Norman, North Carolina. Eng (1979) found C. fluminea population densities in sand bars in the concrete lined Delta-Mendota Canal in California to be between 10,000- 20,000 clams/m-. Population densities of C. fluminea were noted to be greatest in fine sand (452 clams/m-), followed by sand/gravel substrata (177 clams/m-) in the New River, Virginia (Belanger et ai, 1985). In a study on the Wekiva River, F"lorida, Gottfried and Osbourne (1982) reported population densities of 1,210 clams/m". Gardner et al. (1976) reported the C. fluminea popu- lation density increased from 0 to 10,000 clams/m- from 1971 to 1974 in the Altamaha River, Georgia.
Effects of Cohbicvl.x Den.sities on Unionids
I'nionid mussels (Elliptio sp.) were observed in much lower population densities than Corbicula fluminea. Al- though mussels occurred in high density (4,866 clams/ m-) at the Zig-Zag site, this number represented only larval mussels and neither C. fluminea nor Elliptio sp. became established at this site during the study. The largest adult population of unionids was found at the Lake Sawgrass site (Site 2) in November, when 133 unionids/m- were collected. All other sites contained densities of 50 unionids/m- or less, and adult populations were found at only six of the eleven sites. Table 3 shows the mean population densities of unionids at the sampling sites and indicates that density decreases downstream, with few mussels occurring downstream of the Lake Poinsett site (Site 6).
Elliptio sp. population densities were inversely cor- related to those of Corbicula fluminea (F test; p < 0.05). As the mean C. fluminea population density increased in a downstream direction through the first six sites, £/- liptio sp. mean population densities decreased to zero. Of 1,600 bivalves collected from dredge samples, 79.3% were C. fluminea and 20.7% were of the family Union- idae (Elliptio sp. ). Only in the upper reaches of the river, where peat sediments dominated, were Elliptio sp. pop- ulation densities greater than those of the Asiatic clam. In sandy regions where both bivalves occurred, C. flu- minea predominated. Thus, Elliptio sp. predominated only where the sediment type was limiting to C. flu- minea.
SCUBA diving observations at Lake Harney Inlet (Site 8) showed that unionids do exist at the site, even though no individuals were captured in the dredge samples, and revealed the distributional relationships of the two bi- valves under natural conditions. In general, Corbicula fluminea outnumbered Elliptio sp. in the central region of the channel where sandy sediments and measurable flow existed. Toward shore, the sediments changed from sand to silt-covered sand, and then to sand covered with
2.00
.50
1/1 1.00
■» 0.50
I July 12 - Oct. 28, 1984 )
0 500 1000 3000
CORBICULA DENSITY (#/m2)
Figure 3. Cage experiments data .showing the effect of Cor- hicula fluminea densities on grovvtli of Elliptio sp.
heavy accumulations of silt and detritus. Increasing or- ganic silt accumulations near the river banks were ac- companied by increasing numbers of unionids. In con- trast, the number of C. fluminea decreased as silt accumulation increased. It appeared that C. fluminea could not tolerate silt accumulations deeper than 0.5 to 1.0 cm. As the silt depth increased beyond 1 cm, only unionid mussels were observed. The size and shape of the shell of Corbicula fluminea may contribute to its preference for sandy substrates. Corbicula fluminea shells are more circular in comparison to the elliptical shape of the Elliptio sp. Unionid bivalves, being elliptical and usually larger, may extend their shells and siphons be- yond the silt while still remaining within the firm sandy substrate below. In the case of C. fluminea. only large specimens would be able to accomplish this. Smaller C. fluminea. such as those found at Site 8 (20-25 mm size class), would not be able to extend their siphons beyond the silt or muck layer to the more oxygenated flowing river water. The 20-25 mm and 15-20 mm shell-length size classes were the dominant groups collected in the St. Johns River, comprising 46%- and 23% of the C flu- minea found, respectively.
Several investigators have reported that Corbicula flu- minea can outcompete native unionid and sphaeriid bi- valves (Boozer & Mirkes, 1979; Cooper & Johnson, 1980; Taylor & Hughart, 1981). In thisstud\ , growth of Elliptio sp. and C. fluminea were observed together to confirm previous observations that unionid population densities are inversely correlated with C. fluminea population densities. Elliptio sp. mussels, placed in control cages, increased their shell length by an average of 1.76 mm during the period between July 12 and October 28, 1984. Elliptio sp. growth rates in cages that contained various densities of C. fluminea were reduced and the reductions in growth were related to the po[)ulation density of the Asiatic clams in each particular cage. Figure 3 shows the
Page 8
THE NAUTILUS, Vol. 104, No. 1
Table 4. Curbicula growth rales from representative areas of the I nited States
|
Growth rale |
|||
|
Site |
Measurement period |
(mm/day) |
Reference |
|
St. Johns River, FL |
|||
|
Lake Washington |
10/28/84-2/22/85 |
0.03 |
This Study' |
|
Lake Monroe Inlet |
8/15/84-2/23/85 |
0.0197 |
|
|
Lake Monroe Outlet |
8/13 S-)-2 23/85 |
0.0296 |
|
|
Lake Washington |
2/23 85-7 22/85 |
0.0112 |
|
|
Lake Harnev Inlet |
2/23/85-6/30/95 |
0.0437 |
|
|
St. Johns River. FL |
|||
|
Zig-Zag Canal |
1/8/84-7/2/84 |
0.0063 |
|
|
Camp Holly |
9/15/83-7/2/84 |
0,0273 |
|
|
Lake Washington |
1/8/84-7/2/84 |
0.0060 |
|
|
Lake Monroe Outlet |
11/13/83-7/2/84 |
0.0043 |
|
|
Southern Illinois Fish Poiul |
|||
|
Summer |
7/20/79-9/22/79 |
0.012 |
Buttner and Heidinger (1980)- |
|
Winter |
12/6/79-1/16/80 |
0.003 |
|
|
Selected Texas Reservoirs |
1975 |
0.044 |
O'Kane (1976) |
|
.Altamaha River. C,.\ |
1975 |
0.072 |
Sickel (1976) |
|
Oelta-Mendota Canal, C\ |
2/20/73-6/25/73 |
0.0516 |
Eng (1979) |
|
Lake Renbrook, TX |
|||
|
Sandbar Specimens |
6/7/75-9/9/77 |
0.056 |
Britton et al. (1979)' |
|
Container Specimens |
6/14/77-9/30/77 |
0.054 |
|
|
Kanawha River, WV |
|||
|
Container Specimens |
3/12/83-12/16/83 |
0.094 |
Jov (1985)^ |
|
Lake Frie, OH |
6/82-9/82 |
0,114 |
Scott-Wasilk ('/ al. (1983) |
|
Kanawha River, WV |
|||
|
Container Specimens |
Summer, 1983 |
0.136 |
Welch and Jo\ (1984)^ |
1 = 19 liter containers (cages) — with covers, placed on the bottom
2 = Open top cages, 0 3 m- and 9 cm deep, placed on the bottom.
3 = Floating units (each unit consisted of .5 cages).
effect of C. fluminea population den.sities on the growth rates of Elliptio sp. The reductions in growth rates were: 19.3% when the C. fluminea population density was 500 clams/m-; 40.9% for a density of 1,000 clams/m- and 37.5% at a density of 3,000 ciams/m-. The steady de- crease in FJliptio sp. growth is evident at C. fluminea population densities up to 1,000 clams/m-. Beyond this point, for reasons unknown, growth rate reduction seemed to level off. The decreases in growth rate of the Unionidae may have been due to increased competition for essential requirements such as food or oxygen.
In summary, the growth and distribution of Corbicula fluminea in the St. Johns River .seems to be related to substratum and Dow rate. Elliptio sp. growth was ad- versely affected by the presence of C. fluminea. How- ever, the adaptability of this unioiiid mu.ssel to organic sediment types which are generally uninhabitable by C. fluminea may serve to protect it from the dangers of overcrowding or the possibility of becoming replaced altogether by populations of the Asiatic clam.
Growth Raiks
A summary of Corhicula fluminea growth rates at the cage sites, and ;i comparison with growth rates reported
from other areas of the United States, are presented in table 4. Fastest growth was seen at Lake Harney Inlet (Site 8) during the third sampling period (0.0437 mm/ day), as all conditions for growth were favorable at this site (high flow, high D.O., sandy sediment). In general, growth rates in this study were intermediate in com- parison to rates reported in other areas of the United States (table 4), although very low rates were measured at the Zig-Zag (Site 1), Lake Washington (Site 4) and Lake Monroe Outlet (Site 10) sites. The average growth rates reported by Eng (1979) from concrete lined canals in (California, were 0.45 and 0.70 mm for the months of March-May in 1974 and 1976, respectively. By com- parison, the St. Johns River C. fluminea grew an average of 0.70 mm and 1.00 mm during the same months in 1984 and 1985. The data in table 4 were collected from many different aquatic systems with site specific varia- tions in habitat conditions which undoubtedly affect growth rates. Britton et al. (1979) reported on clams grown in lake environments in northern Texas, while the St Johns Ri\ er clams inhabit hiimic-colored waters under both lake and river conditions. The most important fac- tors leading to slower C. fluminea growth in the St. Johns River than in many other areas were probably the lack of food due to low flow rates, periodic low oxygen levels
T. V. Bellinger et al.. 199U
Page 9
in the water column and the predominance of organic sediment in the river.
ACKNOWLEDGEMENTS
The authors with to thank John Platko and Jim Yount for their valuable assistance throughout the course of this research.
LITERATURE CITED
.American Public Healtli .Association 1980 Standard methods for the examination of water and wastewater, 15tli etl .\ P H A , Inc , NY
Belanger, S. E.. J. L. Farris, D. S. Cherry, and J. Cairns, Jr. 1985. Sediment preference of the freshwater Asiatic clam, Corbicula fluminea. The Nautilus 99(2-3):66-73,
Boozer, A. C. and P. E. Mirkes. 1979. Observations on the Fingernail clam, Museulium partumeium ( Pisidiidae) and its association with the introduced Asiatic clam, Corbicula fiuminea. The Nautilus 94(4):1:30-1.'3.5.
Britton, J. C, D. R Coldiron, L, P Evans, C Golightly, K D O'Kane, and J. R TenEyck. 1979. Reevaluation of the growth pattern in Corbicula fluminca (Miiller) /)!; Brit- ton, J. C. (ed.). Proceedings ot the First International Cor- bicula Symposium, Texas Christian University Research Foundation, Fort Worth, Texas, p. 177-192.
BuUner, J K and R. C Heidinger. 1980 Seasonal \ariations in growth of the Asiatic clam, Corbicula fluniinea (Bi- valvia: C^orbiculidae) in a Southern Illinois fish pond The Nautilus 94(1):8-10,
Buzzi, R. A- 1979. Macroinvertebrates of Lake Washington. M.S. Thesis, Floriila Institute of Technolog\ , Melbourne, Florida, 62 p.
Cooper, C. M. and \' W Johnson 1980 Bivalve Mollusca of the Yalobusha River, Mississippi, Tlie Nautilus 94:22-24.
Cox, D T. and D L. Moody. 1980 .\nnual progress report for research project F-.'33-4. Florida Game and Fresh Water Fish C^immission, Tallahassee, Pdorida, 218 p,
Eng, L, L. 1979, Population dynamics of the .Asiatic clam, Corbicula fluminca (Miiller), in the concrete-lined Delta Mendota Canal of Central California. In: Britton, J C. (ed.). Proceedings of the First International Corbicula Symposium, Texas Christian University Research Foun- dation, Fort Worth, Texas, p. 39-68,
Gardner, J .A,. W, R, Woodall, A, A, Staats, and J F Napoli 1976 The invasion of the .Asiatic clam (Corbicula rnan- ilcnsis Philippi) in the .Altamaha River, Georgia The Nau- tilus 90(3):1 17-125,
Gottfried, P K and J, .A Osbourne 1982 Distribution, abun- dance and size of Corbicula rnanilensis (Philippi) in a spring-fed Central F'lorida stream. Florida Scientist 45(3); 178-188.
Cirane), H L, D S Cherr\, J H Rodgers, and J Cairns, Jr 1980, The influence of thermal discharges and substrate composition on the population structure and distribution of the Asiatic clam, Corlricula fluniinea. in the New River, Virginia, The Nautilus 94(4): 130-135,
Hall, J, J, 1984, Production of immaiuTe C'orbicula fluntinca (Bi\alvia: C-orbiculidae) in Lake Norman, North CJarolina, The Nautilus 98(4):153-1.59,
Jov, J, E. 1985, A 40-week study on growth of the .Asian clam, Corbicula flumenea (Muller), in the Kanawha River, West Virginia, The Nautilus 99(4):1 10-1 16,
Llibre, J H 1982 Benthic macroinvertebrates, biological indicators, and diversity indices ot the I'pper St. Johns River, Florida MS Thesis, Florida Institute of Technol- ogy, Melbourne, Florida
Mason, D, R, and T \', Belanger, 1978, Lake Washington: final report Dei)artment of Environmental Science and Engineering, Florida Institute of Technolog), .Melbourne, Florida,
Mattice, J, S 1979 Interactions of Corbicula sp with power plants. In: Britton, J. C. (ed.). Proceedings of the First International Corbicula Symposium, Texas Christian L'ni- versitv Research Foundation, Fort Worth, Texas, p, 119- 1.38,
McMahon, R, F 1977, Shell size-frequenc\ distrilnitions of Corbicula rnanilcnsi.s Philippi from a clam fouled stream condenser. The Nautilus 91(2):54-59.
McMahon, R F 1982, The occurrence and spread of the introduced Asiatic freshwater clam, Corbicula fluniinea (Miiller), in North America: 1924-1982, The Nautilus 96(4): 134-141,
O Kane, K, D, 1976, .A po])ulation studs of the exotic bixaUe Corbicula rnanilensis (Philippi, 1841) in selected Texas Resersoirs, MS, Thesis, Texas Christian Universit\, P'ort Worth. Texas.
Rodgers, J. H., D. S. Cherr\ , R. L Grane\, K L Dickson, and J. Cairns, Jr. 1980. Comparison of heavy metal inter- actions in acute and artificial stream bioassay techniques for the Asiatic clam (Corbicula fluminea). In: J. G Eaton. P. R. Parrish and A. C. Hendricks (eds ). .Aquatic Toxi- cology. .Am, Soc, Test, Mater, Philadelphia, Pa,: 266-280
Scott-Wasilk. J , J S Lietzow, G, G Downing, and K, L Clay- ton, 1983, Growth of Corbicula fluminea in Lake Erie, North American Benthological Society 31st .Annual Meet- ing, La Crosse, Wise, 27-29 April,
Sickel, J, B, 1976 Population growth and productivity of Corbicula rnanilensis (Philippi) in the .Altamaha River, Georgia, ASB Bulletin 23(2):96,
Taylor, R, W, and R, C, Hughart, 1981, The freshwater naiads of Elk River, West \'irginia with a comparison of earlier collections. The Nautilus 95:21-25,
Welch, K J and J E, Joy 1984 Growth rates of the Asiatic clam, Corbicula fluminea (Miiller), in the Kanawha River, West Virginia, Freshwater Invertebrate Biology 3:139- 142.
THE NAUTILUS 104(1):10-15, 1990
Page 10
Multiseasonal Tissue Growth Trends in Corbiciila fliiminea (Bivalvia: Corbiculidae) from the New River, Virginia
Francis G. Dohcrty' Donald S. Cherry John Cairns, Jr.
Dt-parliiifiit of Biology and
I'niversity Center for
Environmental and Hazardous
Materials Studies \ irginia Foiytechnic Institute and
State University Biacksburg, VA 24061, USA
ABSTRACT
Juvenile and adult Corhirula fluminea were collected monthly in 1985 from the New Biver in Narrows, Virginia. Shell length, shell height, shell inflation, and soft tissue dry weight were recorded for each individual Regression analyses among all pairs of data sets were calculated monthly All comparisons among shell dimensions and between shell dimensions and dry tissue weight generated coefficients of determination (B-) >0.801. In all instances, comparisons between shell dimensions and the cube root of dry tissue weight generated higher R- values than comparisons between shell dimensions and dry weight. A comparison of monthly regression lines generated between shell secretion and the cube root of dry weight suggests that shell accretion and ti.ssue grow th are not equivalent for all individuals in a population and are dependent on initial size of an individual and on season.
Key words: Corlncula fluminea: Asiatic clam; shell dimen- sions; tissue weight; regression analvsis.
INTRODUCTION
Studies assessing the growth of Corbicula fluminea (Miil- ier, 1774) have been conducted previously to establish energy budgets for juveniles (Foe & Knight, 1986a), de- termine the effect of various artificial and algal diets and suspended sediment on growth (Dauble et al., 198,5; Foe 6i Knight, 1985), or monitor growth rates of clams under natural conditions (Welch & Joy, 1984; Joy, 1985). In general, these studies monitored individually marked clams or narrow size ranges of clams in the laboratory for defined durations (usually <30 days) or in the field for as long as 4 years. Potential applications for data collected in such studies include use of growth rates as
' Present Address: Syracuse Research Corporation, Merrif Lane, Syracuse. NY 13210.
a sublethal monitor for exposure of clams to to.xic ef- fluents and chemicals (Reianger et ai. 1986a, b; Foe & Knight, 1986b), estimation of soft tissue mass based on shell size in aquaculture efforts (Joy & McCoy, 1975; Buttner, 1986), calculation of condition indices to deter- mine levels of physiological fitness (Joy, 1985), and per- haps as a means by which decisions may be reached concerning optimal periods for chemical control efforts in fouling populations. Few, if any, of these studies ad- dressed growth of both shell and soft tissue simultaneous- ly over a continuum of clam sizes in a natural population. The present study was undertaken to document rela- tionships in tissue weight and shell size in a natural pop- ulation of C. fluminea for a minimum of 1 year to de- termine if the two parameters provided equivalent conclusions concerning growth in C. fluminea.
MATERIALS AND METHODS
Specimens were collected from the New River at Nar- rows, Giles County, Virginia, on the last Monday of each month during 1985. Clams were sampled by means of a .3-m handled dredging cage (mesh size = 7.0 mm), permitting collection of individuals as small as 6 mm in shell length (SL). Clams were returned to the laboratory within 2 hr of collection for measurement of shell di- mensions and dry tissue weights (DW) of 100 individuals. Voucher samples of intact clams have been deposited with the Department of Malacology at the Academy of Natural Sciences in Philadelphia (ANSP A12516).
Shell dimensions measured included shell length (SL), the maximum anteroposterior dimension; shell height (SH), the distance between dorsal and ventral margins of the shell measured at the apex of the umbo; and shell inflation (SI), the lateral thickness of a bivalve (Britton & Morton, 1982). Shell dimensions were measured with vernier calipers to the nearest ±0.05 mm on the intact animal. Prior to shucking the soft tissues from the shell.
F. G. Dohertv cf al., 1990
Page 11
35i
30
15
X
'to
u.
u
.2 10
Q
0-
Discharge Temperature
< I I
J F M
M
J J
Month
1 I
O N D
■30
25
U
|
20 |
|
|
3 |
|
|
«^ |
|
|
(0 |
|
|
b |
|
|
« |
|
|
15 |
|
|
A) |
|
|
►- |
|
|
w |
|
|
0) |
|
|
10 |
^ |
|
$ |
Figure 1. Mean vveekls water temperature (Narrows) and mean dail\ discharge rate (Radford) for the New River, Virginia, in 1985.
mantle cavity water was drained from the clam by sev- ering the shell adductor muscles and standing the clam on the ventral edges of its shell over absorbent paper toweling. Soft tissues were scraped from the shell, trans- ferred to preweighed aluminum pans, and dried in a drying oven at 80 °C for 48 hr. Pans with tissues were weighed on a Mettler balance to the nearest ±0.5 mg. Abiotic data available at the time of the study included New River water temperatures and discharge levels pro- vided by a local industry and federal agency, respectively (figure 1).
Least squares regression (LSR) analyses were per- formed monthly among shell dimensions (SL, SH, SI), between individual shell dimensions and DW, and be- tween individual shell dimensions and the cube root of tissue dry weight (CRDW). Regressions of CRDW against a shell dimension resulted in a linearization of the allo- metric relationship between the untransformed variables (Schmidt-Nielsen, 1984). Generation of LSR analyses was facilitated by programs (general linear models) of the Statistical Analysis System (SAS Institute, Inc., 1982). Coefficients of determination (R-) were generated in con- jvuiction with the LSR analyses as a feature of the com- puter programs employed.
RESULTS
All comparisons among shell dimensions and between shell dimensions and tissue weights generated a R- > 0.801 (table 1). The highest R- values were generated
between SH and SL for shell dimension comparisons and between SH and CRDW for comparisons between a shell dimension and dry tissue weight. Values for R' ranged from 0.988 to 0.996 and 0.895 to 0.970, respectively. Linear regressions of CRDW against shell dimensions always generated better lines of best fit than regressions between untransformed variables.
Intermonthly comparisons of regressions between SH and CRDW revealed marked seasonal trends in weight gain and loss relative to a constant shell size (figures 2- 5; table 2). The monthly regression lines are presented
Table 1. Coefficient of determination (R-) ranges for com- parisons among all potential pairings of shell dimensions and untransformed as well as transformed dr> tissue weights for all collections in 1985.
|
Parameters |
||
|
compared* |
Minimum R- |
Ma.vimum R- |
|
SH, SL |
0.988 |
0.996 |
|
SL, SI |
0.980 |
0 990 |
|
SH, SI |
0.922 |
0.992 |
|
SL, DW |
0.826 |
0-953 |
|
SL, c;rdw |
0.884 |
0.958 |
|
SH, DW |
0.832 |
0.949 |
|
SH, CRDW |
0.895 |
0.970 |
|
SF, DW |
0.801 |
0.935 |
|
SI, CRDW |
0.865 |
0.953 |
* CRDW = cube root dr\ weight, DW = dry weight, SH shell height, SI = shell inflation, SL = shell length.
Page 12
THE NAUTILUS, Vol. 104, No. 1
Table 2. Regression parameters and coefficients ol dcternii- nation (R-) for lines of best fit equations predicting the cube root of dry weight from shell height for clams collected on a monthly basis in 1985 from the New River, Virginia, at the colleclioti temperatures listiil
|
Collec- |
||||
|
tion |
||||
|
temper- |
||||
|
ature |
||||
|
Month |
Slope |
Y-Iiitercept |
R- |
CO |
|
January |
0.0185 |
0.031 |
0.955 |
2.0 |
|
February |
0.0178 |
0 033 |
0.914 |
5.0 |
|
March |
0 0194 |
0.037 |
0.924 |
7.8 |
|
April |
0.0195 |
0.073 |
0.895 |
15.0 |
|
May |
0.0258 |
-0018 |
0.970 |
19.4 |
|
June |
0.0230 |
-0.009 |
0.960 |
22.5 |
|
July |
0.0215 |
0005 |
0.935 |
22.0 |
|
August |
0.0191 |
0017 |
0.939 |
22.0 |
|
September |
0.0182 |
0 026 |
0.956 |
17.0 |
|
October |
0.0178 |
0.028 |
0.943 |
16.0 |
|
November |
0.0188 |
0 0.33 |
0.960 |
95 |
|
December |
0 0192 |
0028 |
0.960 |
2.0 |
in chronological order in figures 2, 3, and 4 to illustrate the month-to-rnonth progressions. Selected monthly regression lines are presented in figure 5 to illustrate comparisons between seasons Although there was a trend towards declining dry weight in all clams in February relative to the initial collection in January, CRDW in- creased among all clams through April (figure 2). This
was demonstrated by progressively higher Y-intercepts, indicating that increases in tissue mass surpassed in- creases in SH (table 2). As a point of reference, a 15-mm (SH) adult possessed 81.5% more tissue (DW) in April than it did in February. The relationship between CRDW and SFJ shifted in May from that previousK observed, as demonstrated by an increase in the slope of the regres- sion line. Larger individuals (>13 mm SH) possessed more tissue mass relative to SH than in previous months, while smaller individuals (<13 mm SH) had less tissue relative to SH in May than in previous months (figure 2; table 2). Declining slopes and increasing intercept values were observed from May through October (figures 3, 4; table 2) until a distinct increase in CRDW relati\e to SH was observed in November and December (figures 4, 5). This shift in the regression lines coincided with major flooding of the New River in early November (figure 1). As a point of reference, a 15-mm (SH) adult possessed 22 and 23% more tissue (DW) in November and Decem- ber, respectively, than it did in October.
DISCUSSION
Regressions among shell dimensions and between shell dimensions and tissue dry weights generated high R- values that were comparable to the findings of other investigators. The approach to analysis of the data gen- erated in this study differed from that used by others, in that some investigators failed to transform their data (Joy & McCoy, 1975; Rodgers et al., 1977) while others uti- lized a log-log transformation prior to generating lines
06- 04-
^ 0.2
I 06-1
?r> 0.4-
02
0.0
— r- 8
12
16
20
— r- 4
8
— I— 12
—I — 16
20
Shell Height (mm)
Figures 2-5. Ni'.nlhlv lines of best fit for the cube roots of tissue dr\ weiglit regressed against shell height for CorhUula fluniinea indi\idudK o.Jlf. I. d troni the New River, Virginia, in (2) January, February, March, .Xpril, and May; (3) May. June, and .August; (4) August SeptcMili r October, and November; and (5) February/October, ,\pri], November, and December, 1985.
F. G. Dohertv ct al., 1990
Page 13
of best fit through regression analysis (Sickel, 1979; Al- dridge & McMahon, 1978; Kennedy & Heukelem, 1985; Foe & Knight, 1986a, 1987). Comparisons between a shell dimension and either viscera wet or dry weight reveal a curvilinear relationship that is not appropriate!) ana- lyzed b> linear regressions. While log-log transformations do provide a linearization of the relationship between these variables, we believe that use of a cube root trans- formation may be more biologically appropriate, because body weight is a function of volume and height is a measure of a single, linear dimension. Transformation of weight to its cube root permits a simpler linear regres- sion comparison between shell dimensions and tissue weight rather than regressions between log-log trans- formed variables. Previously, Dauble et al. (1985) uti- lized a similar approach by regressing the square root of clam weight against SL. One other factor distinguishing our study from those previously reported is that all of the above cited studies used either SL or SI in regressions against tissue weight. Our data demonstrate a lower de- gree of variability in measurements of SH and, therefore, greater precision in the estimation of tissue weights.
Regressions of CRDW against SH (figures 2-5; table 2) demonstrated that no single monthly or quarterly es- timate of tissue mass based on SH can be extrapolated to all other periods of the year. Consistent slopes for the relationships from January through April suggested that the individuals from all size classes were responding to environmental variables in a proportionately common fashion through either the loss (January to February) or accumulation (February through April) of tissue. While the manner in which the data were collected prohibits statements concerning actual shell growth rates, the fact that Y-intercepts declined and increased demonstrates active soft tissue degradation and growth, respectively, at rates not comparable to shell growth. The slope of the regression line describing the relationship rose markedly in May, documenting a change in the relationship among different size clams. Larger individuals were apparently accumulating tissue at a rate proportionately greater than previously observed. Smaller individuals were most likely continuing to accumulate tissue, but the apparent re- duction in tissue mass relative to SH probably signified a rapid increase in rate of shell growth.
The increase in tissue mass in larger individuals ( ~ 15 mm and greater) in May was most likely in preparation for reproductive activities, while the marked decrease in slope of the regression line from May to June could have reflected initiation of spawning. Reproductive effort in this population for 1984 was greatest during June and July (Dohert> et al., 1987). This interpretation is consis- tent with the observations of Morton (1982). He reported a 42?t decline in the slope of the regression line between DW and SL for groups of Corbicula fluminialis collected both prior to and after spawning. In contrast, Aldridge and McMahon (1978) did not find significant differences for regressions between log transformed variables of SL and DW for 28 groups of Corbicula fluminea collected over a 16-month period. The gradual reduction in slope
from June to October may have reflected a continuing release of juveniles by adults, although the need for in- creased energy e.xpenditure during the warmest period of the year may have also contributed to the decline.
The changes in CRDW relative to SH for smaller clams (~10 mm or less) between April and May were probably a reflection of increased shell secretion rather than tissue loss or resorption. If clams of this size were sexually immature, they would not require a massive increase in tissue to accommodate reproductive efforts. An overlap of the April and May regression lines for clams ranging in size from ~10 to 14 mm may indicate that physio- logical activities are allocated equally to shell secretion and tissue growth. This interpretation also suggests that size of an individual at the time of spawning dictates the total number of veligers released by that individual.
Increases in the slopes and Y-intercepts for November and December could have been due to tissue growth, resulting from an abundance of nutritive material as- sociated with high river discharge from locally heavy flooding (figure 1). Doherty et al. (1987) hypothesized that high river discharges provided high levels of nu- trients that permit more than two spawning episodes per year while Foe and Knight (1985) concluded that sus- pended sediments, up to a concentration of 150 mg/liter, do not adversely affect growth of the Asiatic clam. Since lower temperatures during these months might result in reduced metabolic demands, the potential for growth and maintenance of tissue mass could have been en- hanced.
These data also support earlier observations by other investigators that an inverse relationship exists between growth rate and initial size of an individual (Britton et al, 1979; Dreier & Tranquilli, 1981; Welch & Joy, 1984). For example, a 6-mm (SH) juvenile had a dry weight of 2.7 mg in February, whereas the dry weight of an in- dividual of similar shell size had a dry weight 154% greater in April. The increase in tissue mass for a 20- mm (SH) adult was only 68% between February and April (59 and 99 mg dry tissue weight, respectively).
Similarly, the magnitude of the difference between regression lines between any two months is unequal, supporting observations by other investigators that growth is seasonally influenced. Both Fuji (1957) and Joy (1985) observed no growth (SL) in clams maintained at water temperatures <10°C. Measurable growth was observed when temperatures rose above 14 °C, while the greatest rates of growth were observed at 24 to 30 °C. Britton et al. (1979) reported a slowing of shell deposition in clams with shell >10 mm in length during winter, while McMahon and Williams (1986) found growth rates of Corbicula fluminea individuals to be characterized by large seasonal variation. Mattice and Wright (1986) ob- served varying growth rates for the Asiatic clam in field studies and suggested that temperature played a major role in growth determination. These conclusions, though, were formulated from observations of shell growth rate. Our study demonstrates that growth of tissue can occur at temperatures below those which appear to be necessary
Page 14
THE NAUTILUS, Vol. 104, No. 1
for measurable increases in sliell height, length, or infla- tion (February to April; October to November; table 2). Russell-Hunter et at. (1984) have reported comparable observations for populations of freshwater puimonate snails. Comparisons between pre- and post-winter sur- viving individuals of Helisoma trivolvis and Lijmnaea palustris revealed reductions in soft tissue ranging from 19-169% ba.sed on predictive equations between shell and tissue ma.ss for pre-winter snails.
This study demonstrates that shell growth as defined bv increases in shell height, length, or inflation is not equivalent to, and does not necessarily parallel, tissue growth. Initial size, reflective of the reproductive ma- turit\' of an individual, and season, reflective of temper- ature and food availability among other things, are pos- sibK' major factors in determining whether shell or tissue growth will predominate. These data imply that regres- sions between a shell dimension and soft tissue mass gen- erated at one time of the year are not applicable to the same population in other months or seasons.
ACKNOWLEDGEMENTS
This research was funded in part by a grant from Amer- ican Electric Power Company and a Cunningham Dis- sertation Year Fellowship awarded to the senior author by Virginia Polytechnic Institute and State University. Water temperatures and discharge rates for the New River were provided by R. Roy (Celanese Corporation) and H. Williams (United States Geological Survey), re- spectively. Appreciation is extended to J. Grudzien for drafting the figures, to Daria Donald for editorial assis- tance, and Betty Higginbotham for typing the final draft.
LITERATURE CITED
Aidridgf, D W and K V McMahoii 1978. Growth, fecun- dity, and bioeneri^etics in a natural population of fresh- water clam, Corhinilu riuinilrnsis Pliilippi, from North Central Texas. Journal Molluscan Studies 4^:49-70
Belanger, S. E., 13. S. Cherry, and J Cairns, Jr. 198(ia. Sea- sonal, behavioral, and growth clianges of juvenile Corl/ic- ula fluminea exposed to chrysotile asbestos. Water Re- search 20:1243-1250.
Belanger, S. E., J. L. Farris, I). S Cherry, and J Cairns, Jr 19S6b. Growth of Asiatic clams (Corlnrtda sp ) during and after long-term zinc exposure in field-located and laboratory artificial streams. Archives Eru ironmenlal ( loii- laniination Toxicology 15:427-4.34
Brilton. J C. and B Morton. 1982 A dissection guide, field and laboratory manual for the introduced bivalve Corlric- ula fluminea. Malacological Review Supplement No. 3. 82 p.
Brilton, J. C, D. R C;oldiron, L. P. Evans, Jr., C. Golightlv, K. D O'Kane, and J. R. TenE\ck 1979. Reevaluation of I Ik- growth paltern in Corbkula fluminea (Miiller). In: liritlon, J (; (ed.). Proceedings of the First International Ciirlnnila Svniposium. Texas Christian University Rc- scarcli 1-oiindalion. IVjrl Worth, TX, p. 177-192.
Butlner, J K l')8B Biology of Corbicula in catfish rearing ponds In: Brill. .n. J C (ed.). Proceedings of the Second
Inlernalional C'orhicula Symposium .Xmerican Malacol- ogical Bulletin Special Edition No. 2:211-218.
Dauble, D. D., D. S. Daly, and C. S. Abernathy. 1985. F"actors affecting growth and survival of the Asiatic clam, Corbic- ula sp., under controlled laboratory conditions. In: Card- well, R. D., R. Purd\ and R C. Bahner (eds ). Aquatic Toxicology and Hazard Assessment: Seventh Symposium. STP 854. American Societv for Testing and Materials, Philadelphia, p 1.34-144.
lioherty, F G., D S. C^herry, and J. Cairns, Jr 1987 Spawning periodicity of the Asiatic clam, Corbicula fluminea in the New River, Virginia. ,'Vmerican Midland Naturalist 117: 71-82,
Oreier. H and J. Tranquilli. 1981. Reproduction, growth, dislribution, and abundance of Corlncula in an Illinois cooling lake. /;i; Larimore, R W. and J. .\. Tranquilli (eds.). The Lake Sangchris study: case history of an Illinois cooling lake. Illinois Natural Historv Survev Bulletin .32: 378-393.
Foe, G and A. W. Knight 1985. The effect of ph\ toplankton and suspended sediment on the growth of Corbicula flu- minea (Bivalvia). Hydrobiologia 127:105-115.
Foe, C. and A. W Knight. 1986a. A thermal energy budget for juvenile Corbicula fluminea. In: Britlon, J. G (ed.) Proceedings of the Second International Corbicula S>tn- posium. American Malacologiral liulletin Special Edition No. 2:14.3-1.50.
¥oe, C. and A W. Knight. 1986b. .\ method for evaluating the sublethal impact of stress employing Corbicula flu- minea. In: Brittou, J. G. (ed). Proceedings of the Second International Corlncula Symposium. American Malaco- logical Bulletin Special Edition No. 2:133-142.
Foe, G and A. W. Knight. 1987. Assessment of the biological impact of point source discharges employing Asiatic clams. Archives Environmental Contamination Toxicology 16:.39- 51.
F'uji, A. 1957. Growth and breeding season of the brackish water bivalve, Corbicula japonica in Zyusa-Gata inlet. Bulletin of the Facult\ of F"isheries, Hokkaido I'niversit) 8:178-184.
Joy, J. E 1985, A 40-week stud\ on growth of the .\sian clam, Corlncula fluminea (Miiller), in ihe Kanawha River, West Virginia. The Nautilus 99:110-116.
joy, J. E. and L. E. McC^ov. 1975. Compari.sons of shell di- mensions and viscera mass weights in Corbicula nianilcn- sis (Philippi, 1844). The Nautilus 8951-54.
Keiuiedy, V. S. and L. Van Heukelem. 1985. Gametogenesis and larval production in a population of the introduced Asiatic clam, Corlncula sp. (Bivalvia: (-orbiculidae). in Maryland Biological Bullelin 168.50-60.
Mallice, j S and I, D. Wright 1986. Aspects of growth of Corbicula fluminea. .Vmerican Malacological Bulletin Spe- cial lulition No, 2:167-178.
McMalion, R. F. and C. J. Williams 1986 .\ reassessment of grow th rate, life-span, life-cycles and population dynamics in a natural population and field caged individual of Gor- bicula fluminea (Miiller) (Bivalvia: Gorbiculacea) In: Bril- ton, J, (;. (ed). Proceedings of the Second International Corbicula S\niposium .American Malacological Bullelin Special Edition No, 2: 151-166,
Morton, B, 1982, Some aspects of ihe [jopulalion sirueture and sexual strateg\ of Corbicula ef fluminialis (Bivalvia: Gorbiculacea) Irom the Pearl River, Peoples Republic ol China Journal of Molluscan Studies 48: 1 -23
Kodgers, J H , Jr . D S Cherry. J R Clark, K E Dickson,
F. G. Doherty et al.. 1990 Page 15
and J. Cairns, Jr 1977 The invasion of Asiatic clam, Sickel, J 1979. Population d>'naniics of Curhicula in the Al-
Corbicula manilcnsis in tfie New River, Virginia. The taniaha River, Georgia 7n. Britton, J. C;. (ed). Proceedings
Nautilus 91:43-4(1 ot the First International Corhiciila .Symposium Texas
Russell-Hunter, W D., R A. Browne, and D W Aldridge Christian Llniversit\ Research Foundation, Fort Worth, p
1984. Overwinter tissue degrowth in natural populations 69-80.
of freshwater pulmonate snails (Helisoma thvolvis and Welch, K. J. and J, E. Joy 1984 Growth rates ol the Asiatic
Lymnaca palu.slris). Ecology (55:22.3-229. clam, Corhiciila flurninea (Miiller), in tlie Kanawha River,
SAS Institute, Inc. 1982. SAS user's guide: basics, 1982 ed. West Virginia, Freshwater Invertebrate Biology 3:1.39-
.SA8 Institute, Inc., Gary, North Garolina, 923 p. 142.
Schmidt-Nielsen, K, 1984. Scaling, why is animal size so im- portant'r* C^ambridge I'niversity Press, Cambridge, 242 p.
THE NAUTILUS 104(1): 16-25, 1990
Page 16
Geological Substrate and Human Impact as Influences on Bivalves of Lake Lewisville, Trinity River, Texas
Raymond W. Neck
Texas Parks and Wildlife Department 4200 Smith School Road Austin, Texas 78744, USA
ABSTRACT
The bivalve fauna of Lake Lewisville (Elm Fork Trinity River), Denton County, Texas, consists of 16 species. Present are the introduced Asian clam and 1,5 native unionids. Relative abun- dances of species in different areas of the reservoir are related to inundation history and geological substrate Inundation has localK extirpated some species while other species ha\e flour- ished. Utilization of shell material for the cultured pearl in- dustry is documented. Ecological, taxonomic, and zoogeo- graphical notes are presented for each species.
Ketj icords: Freshwater bi\aKes; Lake Lewisville; Trinity Riv- er, faunal changes; commercial utilization.
INTRODUCTION
Little is known of the detailed distributions of the fresh- water mussels of Texas. Two comprehensive lists have been published (Singley, 1893; Strecker, 1931), but these compilations are in need of updating. Even recent treat- ments of North .\inerican unionids (Burch, 1973, 1975) do not adequately cover the Texas fauna. The only stud- ies of freshwater bivalves from north central Texas lo- calities cover Lake Texoma (N'alentine & Stansbery, 1971; White and White, 1977) and Lake ,\rrowhead (Neck, 1989b). Murray (1972, 1978) has summarized the unio- nids present in two reservoirs in central and southern Texas. Localized faunal surveys of freshwater bivalves of other portions of Texas have been published recently (Neck, 1986, 1987, 1989a; Neck ti Metcalf, 1988).
Below is a summary of a survey of the mussel fauna of Lake Lewisville, a reservoir in north central Texas on the Elm Fork of the Trinity River (figure 1 ). The purposes of this survey were to determine relative abundance of resident species, intra-reservoir distributions of various species, and human impact upon this fauna. Justifications for the nomenclature used are provided where proper usage has been unclear; nomenclature follows Turgeon pl al. (198S).
Previous reports of freshwater bivalves from the upper Trinity River drainage have been published. Flook and Ubelaker (1972) reported nine species from a single lo- cality in Lake Lewisville. Strecker (1931) reported four-
teen species from the Elm Fork of the Trinity River "near Lewisville, Denton County. The naiad fauna of Dallas County (which borders the southern edge of Den- ton County) was studied by Read (1954; Read & Oliver, 1953). A survey of unionids of several reservoirs of Tar- rant County (Fort Worth, to the west of Dallas County) is available (Mauldin, 1972).
STUDY AREA
Lake Lewisville (figure 2) is located in north central Texas in central Denton County, approximately 24 ki- lometers southeast of Denton and 35 kilometers north- west of Dallas. Impounded watercourses include the mainstem and lower reaches of some tributaries of the Elm Fork of the Trinity River. The Elm Fork of the Trinity River is formed from the coalescence of many small tributaries in Cooke, Montague, Clay, and Archer Counties to the west of Denton County.
Lake Lewisville has a dual history; information below is from Dow ell and Breeding (1967). The original im- poundment (Lake Dallas) was created by Garza Dam built during 1924 through 1927; deliberate impound- ment of water began 16 February 1928. The area of the original impoundment was 44.5 km- at spillway eleva- tion. Original capacity was 2.4 million cubic meters (drainage area 3,018 km-). Accumulation of sediment became a severe problem in the original Lake Dallas. By 1952, capacity of the reservoir had decreased 19.3% to 1.9 million cubic meters. Hydrochemical and vegeta- tional conditions of Lake Dallas were reported by Harris and Silvey (1940).
Construction of a second dam downstream near Lew is- ville was begun in November 1948 and completed in .■\ugust 1955. Impoundment of water began 1 November 1954. Following a prolonged filling period during a se- vere drought, a passageway was created through Garza Dam on 28 October 1957. The combined reservoir system has a surface area of approximately 94.28 km- at con- servation pool level (156 meters above mean sea level). Surface area of the flood pool (161 m msl) is 158.17 km^. Capacity of the combined reservoir system is 5.7 million cubic meters at conservation ()ool and 12.2 million cubic
R. W. Neck, 1990
Page 17
Lake Bridgeppr t
.^Lahe Ray Roberts
Lake Lewisville
Lake Lavon
Grapevine Lake
Lake Ray Hubbard Cedar Creek Res.
Lake Worth Benbrook Lake
Lake Arlmgtor) Mountain Creek Lake
Navarro Mills Lake
Fairfield Lake
Lake Livingston-
TRINITY RIVER DRAINAGE
Houston County fles
Lake Anahuac -
Figure 1. Mali "f TriiiiU Knci drainage, Texas, showing location of Lake Lewisville and other reservoirs.
LAKE LEWISVILLE
Figure 2. Map of Lake Lewis\ ilie, Texas, showing geological snlistrate, reservoir subdivisions (Roman numerals), and col- lecting localities (Arabic numbers;.
meters at spillwav level. Drainage area above the dam is 4,300 square kilometers. Shoreline of the conservation pool is appro.ximateK 295 kilometers. Primary purposes of the reservoir are flood control, municipal/industrial water supply, and recreation.
More recentK Smith (1973) studied the physicochem- istrv of Lake Lew is\ ille. Nariation in water phv siochem- ical parameters was found to be due more to the original characteristics of the basin rather than the length of impoundment. Algal species composition was fairly uni- form throughout the surveved portions of the reservoir. Water temperature varied seasonally from 5.0 °C to 28.5 °C and pH varied from 7.3 to 8.4. Alkalinit)' varied from 90 to 107 mg/L (mostly bicarbonate) for area II and from 116 to 151 mg/L for area I. Nitrate levels varied from 0.354 to 3.588 mg/L, while phosphate levels ranged from 0.017 to 0.165 mg/L. The Lake Dallas basin (area I) had greater turbiditv' and higher nutrient enrichment (phosphate and bicarbonate) than area II.
This reservoir has suffered from a lack of name stan- dardization. Originally both the combined impound- ment and the dam structure were known as Garza-Little Elm Reservoir and Garza-Little Elm Dam. In 1955 the name of the dam was changed to Lewisville Dam al- though the reservoir name was unaltered Subsequently the U.S. Army Corps of Engineers (which operates the dam and reservoir) has changed the name of the reservoir to Lake Lewisville.
The surface geology of the area covered by Lake Le- wisville is rather simple (VVinton, 1925). The eastern portion is underlain bv the Eagle Ford Formation and alluvial deposits, whereas the western portion is under-
lain by the Woodbine Formation and limited alluvial areas. All deposits are Upper Cretaceous except for the Pleistocene and Recent alluvial terraces. The Eagle Ford consists of a series of black oily shales with a few thin ledges of sandstone. The Woodbine is somewhat variable ( Winton, 1925); several lavers of indurated sandstone are separated by softer sandstone, loose sand, and clav' layers. The Eagle Ford /Woodbine contact is aligned approxi- mately along a NNE to SSW line and passes very close to the axis of Garza Dam, w liich formed Lake Dallas.
Climate of the studv area is transitional between mar- itime-subtropical and continental-temperate. The near- est recording weather station is at Denton, where the average monthly temperature varies from 7.2 °C in Jan- uary to 29.3 °C in .\ugust. Extreme temperatures re- corded are 45 °C and —19.4 °C. Annual precipitation averages 804 mm, but has varied from 384 mm in 1963 to 1,433 mm in 1957. The growing season is 226 days (27 March to 8 November). Weather records for any particular year often are far from the mathematical "norms" because this region is characterized b> dramatic year-to-year fluctuations. Fluctuations in precipitation usually are larger than those in temperature. Major droughts occurred in the 1930's and 1950's.
Drought during the mid 1950's was severe enough that 1.2 million cubic meters (98,470 acre-feet) of water were diverted from the Red River into Lake Dallas. Water was pumped from the Red River in Cooke County into Pecan Creek through which the water flowed by gravity into the Elm Fork of the Trinitv River (Dovvell & Breed- ing, 1967:36).
Page IS
THE NAUTILUS, Vol. 104, No. 1
METHODS
Twelve survey sites (Appendix) were chosen in a manner that all major areas of the reservoir were sampled. Most of the sites were located in various recreation parks built by the U.S. Army Corps of Engineers. Time of sampling activities (Winter 1977 through Fall 1978) coincided with an extended drought, which resulted in substantial low- ering of the reservoir level. Many hectares of reservoir bottom were exposed to air. Bivalve shells were extremely abundant and readily counted.
Survey transect areas were four meters wide along the water edge for varying distances. Length of transects varied from 50 to 70 meters, but some were lengthened be\ond 70 meters in order to increase sample number. Counts should not be taken as relative densities, but as estimates of relative species occurrence at particular sites. Only paired valves were counted in order to reduce the effect of water movement of "dead" valves to localities unsuitable for the species. Such movement is believed to be of minimal significance because most valve pairs lay in situ, partialK' covered with sediment at the place of death. .After counts along the pre-selected transect were completed, additional lengths of adjacent reservoir edge were walked. Additional species at times were added to the list of species occurring at a given sampling area. Such occurrences are not recorded in the relative counts for a particular site (tables 1 and 2).
Representative specimens collected during this study have been deposited in the Dallas Museum of Natural Historv.
BIVALVE FAUNA
A total of 16 species were observed at the various sam- pling stations around the reservoir shore (table 1). All but one, Corhicula fluminea, are native members of the Unionidae. No fingernail or pea clams (family Sphaeri- idae) were observed during this study. Below is a list of species recovered from Lake Lewisville with nomencla- torial discussion, publisheil haliitat notations, and habitat occurrences in Lake Lewisville.
Corbicula fluminea (Miiller, 1774) was not abundant in Lake Lewisville; no living specimens were found. Fa- vorable habitat areas (moving water over sand or gravel substrate) were in small creeks feeding into the reservoir. A few young shells (7 mm length) were found on sand at Fish-O-Hama (private commercial development). All specimens from Lake Lewisville were referable to the "white form" (Hillis & Patton, 1982).
Anodonta grandis Say, 1829, is an extremely variable taxon as several names have been applied to different phenotypes. Read (1954) reported this species to be the 'most abundant and widely distributed species in Dallas Coimty, ' but referred his specimens to A. corpulcnta '-('opei. 1S.'34; Strecker (1931) called all specimens A. taaudus Lake Lewisville specimens tended toward the corpuhnln phuiiolype (largest specimen measured 148.3 mm in slieli Irngth). A. grandis was a common species
in Lake Lewisville; 106 specimens were taken, and all 12 reservoir localities were represented (table 1).
Anodonta imbecillis Sa\, 1829, occurs in the eastern United States, throughout the entire Mississippi system, and southward through the Gulf drainages into Mexico (Simpson, 1914:396; Burch, 1975:15). Mauldin (1972) re- ported A. imbecillis to be more frequent in ponds and small reservoirs than in large reservoirs. Only 18 indi- viduals of A. imbecillis from 8 scattered localities were found in Lake Lewisville (table 1). Anodonta imbecillis probably was more abundant in backwater sloughs and pools of small creeks that drain into Lake Lewiss ille.
Arcidens confragosus (Say, 1829) is distributed throughout the Mississippi drainage (Murray is. Leonard, 1962). In Dallas Co., Read (1954) found A. confragosus only in Parson's Slough in shallow water with a "fair current " over a mixed sand and mud substrate. This species was found at 9 reservoir localities, but only 16 individuals appeared in 7 transects (table 1).
Amblema plicata (Say, 1817) was the most abundant naiad in Lake Lewisville; 624 specimens (38.8% of total) were counted at 12 transect locations (table 1). This species was the most abundant bivalve at all locations. Amblema plicata occurs throughout much of eastern North Amer- ica, south to the Nueces River, Texas (Burch, 1975). A number of taxa have been established for the A. plicata complex in the United States. Read (1954) reported both A. costata Rafinesque, 1820, and A. perplicata (Conrad, 1841) from the Elm Fork of the Trinity River in Dallas County. Flook and Ubelaker (1972) recorded both A. plicata and A. costata for Lake Lewisville, but only 4 of 150 were referred to A. costata. These two forms are believed to be either genetic morphs or ecophenotypes; in either case no taxonomic rank is recognized herein.
Quadrula mortoni (Conrad, 1834) is restricted to the eastern half of Texas (Strecker, 1931). This species is represented in Lake Lewisville by pustulate and non- pustulate forms, which are known from reservoirs in neighboring Tarrant County (Mauldin, 1972). Some of the less angulate specimens, particularly those with a large number of pustules, approach Quadrula pustulosa (Lea, 1829). However, specimens similar to Q. pustulosa from Lake Lewisville differ from Q. pustulosa from southeastern Texas in general shape of shell as well as number, form, and arrangement of pustules. Specimens of Q. mortoni differ from Q. pustulosa by being broader and somewhat flatter along the dorsal portion of the valves. Individuals of Q. mortoni (pustulate and non- pustulate) in Lake Lewisville are most abundant on a sand substrate, even if the sand exists only as a shallow bar over bedrock shale (as in area II).
Shells referred to t\ pical Q. mortoni in this stud) can be keyed to Q. houstonensis (Lea, 1859) b\ using Read (1954), who reported the latter taxon to be "not common in Dallas County," from Elm Fork of the Trinity River on gra\el bottom in about a meter of water. Strecker (1931) noted, however, that Q. houstonensis from the Elm Fork near Lewisville was "rather inflated and seems peculiar to this branch of the Trinity." Examination of
R. W. Neck, 1990
Page 19
a o _o
c
a
-J
Z ° ■-
to C] a? 00 CJ O^ C] -^ CJ ^ (M CJ O (M IC -^
£ P
C— irtM— IOC —I [~X1-T00 (£■
-^ <D CM oq
|0)(M<MO-^t~- \ X^ |-^0OI-a^» O <r>tC
iC o
— ' t~- c] -r — >
Z^ I ^ I T — CD X! I -H
-^ 00
T I QC I
lO -r 00 lo I — <
^-rci— "O^TO I 00 icoc^ot I 00 r^r
I ^
* C] — < CI CO I ^ CO O'
CO -^ a>
00
T CO I —"CD
|-;|-r|,^|^^|^^
I -^ I I ?? " - I 2 I
I ■"' r' ,■;? - s I - I
» coco* CO* io» <y>
<M O) — 00
2.
I ^-o,
I CO [ lO — (
|
Oi |
c |
W) |
|
|
rt |
|||
|
m |
(— > |
c |
|
|
■^ |
V, |
||
|
Clj |
|||
|
._ |
_Q |
||
|
^_^ |
~c |
P |
|
|
c |
— |
||
|
- — |
r |
^ |
|
|
OJ |
|||
|
-^ |
CJ^ |
.^ |
|
flu mini grandi inihcci |
^■f |
||
|
a o a |
■iJ -^ |
||
|
~^ "^ ~ |
|||
|
'~ o o |
*^ w |
y s. |
|
|
"^ ~^ |
|||
|
"t; o o |
'r* "^ |
^3 a |
-^ <>- |
|
^ < < |
< -^ |
s-A ,»r |
r— 1-^ |
, at ?
■ o c
S S 5 5. ^ t ^ ? ^
■"-■--:-J'~l'-ja,&.i~'r~ JT —
o.
c
|
Page 20 |
THE NAUTILUS, Vol. 104 |
, No. 1 |
|||||||
|
Table 2. Relative counts and percentages |
of bivalves |
of Lake |
Lewisville and |
subdivisions |
|||||
|
1 |
11 |
III |
Total |
||||||
|
n |
r;** |
n |
^; |
n |
'■; |
n |
'■; |
||
|
Corbicula fltiminea |
* |
— |
5 |
0.6 |
1 |
0.2 |
6 |
04 |
|
|
Anodonia grandis |
16 |
5.4 |
50 |
6.2 |
40 |
/ - / |
106 |
6.5 |
|
|
Anodonta imliecilis |
4 |
1.3 |
/ |
0.9 |
/ |
1.3 |
18 |
1.1 |
|
|
Arcidens confragosus |
4 |
1.3 |
2 |
0.2 |
10 |
1.9 |
16 |
1.0 |
|
|
Aniblema plicala |
128 |
42.8 |
301 |
37.5 |
195 |
37.6 |
624 |
38.5 |
|
|
Quadrula morttmi |
3 |
10 |
8 |
1.0 |
2 |
04 |
13 |
0.8 |
|
|
Qiiarida apictilala |
83 |
27.8 |
116 |
14.5 |
82 |
15.8 |
281 |
17.3 |
|
|
Tritogunia verrucosa |
* |
— |
— |
— |
— |
— |
* |
— |
|
|
Lampsilis hiidiana |
13 |
4.3 |
124 |
15.5 |
77 |
14.8 |
214 |
13.2 |
|
|
Lampsilis satura |
— |
— |
* |
— |
— |
— |
* |
— |
|
|
Lampsilis teres |
6 |
2.0 |
50 |
6.2 |
20 |
3.9 |
76 |
4.7 |
|
|
Leplodea fragilis |
3 |
10 |
37 |
4.6 |
23 |
4.4 |
63 |
3.9 |
|
|
Polarrtdus amphichaenus |
3 |
10 |
16 |
2.0 |
21 |
40 |
40 |
2.5 |
|
|
Potamilus purpura! us |
26 |
8.7 |
43 |
5.4 |
19 |
3.7 |
88 |
5 4 |
|
|
Toxolasma parvus |
* |
— |
6 |
0.7 |
* |
— |
6 |
0 4 |
|
|
TrunciUa truncata |
10 |
3.3 |
37 |
4.6 |
22 |
4.2 |
69 |
4.3 |
|
|
Si^ecies |
15 |
— |
15 |
— |
14 |
— |
16 |
— |
|
|
Individuals*** |
299(13) |
— |
802(14) |
— |
519(12) |
— |
1,620(14) |
— |
|
|
% of Total Sample |
18.5 |
— |
49 5 |
— |
.32 0 |
— |
100,0 |
— |
* Present, but not recorded in transect. ** % of transect sample *** N'imiber in parentlieses is number of species present in transect.
shells at the Streckcr Museum (SM) from the Elm Fork near Lewisville identified as Q. houslonensis by Strecker (SM 325-329) revealed shells of Q. pustulosa that are somewhat more ciuadrate than typical Q. mortoni. No such shells were found in the present survey. Examina- tion of other shells referred to Q. houslonensis by Streck- er revealed robust shells that appear to represent several species of Quadrula.
Quadrula nodulata (Hafinesque, 1S20) has been re- ported from various portions ot eastern Te.xas (Strecker, 1931). A single specimen that resembles Q. nodulala was found in Lake Lewisville in transect samples. Exami- nation of specimens from Lake Lewisville that resemble Q. nodulata indicated that these shells were Q. mortoni. These Lake Lewisville specimens did not exhibit nodules on the posterior ridge as in typical Q. nodulata; nodules are restricted to the middle of the shell (below the umbo area).
Read (1954) reported Quadrula metanevra (Hafin- esque, 1820) from adjacent Dallas County. These shells may have been these nodtdala-]\ke shells or an extremely angulate Quadrula apiculata.
Quadrula apiculata (Say, 1829) ranges from the Rio Grande through all Texas streams to the .\labama River ( Xeel, 1941). The southern maple-leaf mussel is the sec- ond-most abundant naiad species in Lake Lewisville; 281 individuals were taken at all 12 sites (table 1). Read I HJ.J4) rcpiirtcd two phenotypes in Dallas County in- cluding l"lm Fork below the present Lake Lewisville: 1) "specinsu [.( 1, 1 sfi2" with pustules extending to the ven- tral margin, and 2 "for.sheyi Lea, 1859" with pustules
only on the more dorsal portions of the valves. Read (1954) reported that both forms prefer sand bottoms; "speciosa" tended to be found in shallow water while "forsheiji" tended to be found in fairK- deep water. These morphological tvpes represent genetic variation in the Q. apicidata population, but they ma> also be the result of reduced rates of pustule formation in older individuals. Neel (1941), who treated apiculata as a form of Quadrula quadrula (Rafinesriue, 1S20), presented a discussion of the iorms of the Q. quadrula group.
Tritogonia verrucosa (Rafinesque, 1820) has a wide distribution throughout the Mississippi drainage and oth- er Gult coastal tlrainages from Georgia to Texas (\'al- entiiie & Stan.sbery, 1971). In Dallas County, Read (1954) found it only in Elm Fork, where it was "perhaps the most abundant species," on hard gravel or sand in fairly deep water in sw ift current This species most often has white nacre; pink and purple nacres become more com- mon in the southern part of its range according to Val- entine and Stansbery (1971), who found few specimens in Lake Texoma (all of which had white nacre). All specimens located in this study have white nacre. This spe'cies is extreme!) uncommon in Lake Lewisville; no specimens were encountered in the transect censuses (only one specimen was found, at Graveyard Slough, which is near an incoming creek, w hich would "freshen" the water i)ualitv ) The raritv of T. verrtico.sa in Lake Lewisville is the result ol its requirement for a rapid current of water.
Lampsilis hydiana (Lea, 1838) ranges from eastern Texas and Oklahoma eastward to Arkansas and Alabama
R. W. Neck, 1990
Page 21
(Uurcli, 1973:2U). L. hijdiana was reported rare in Dallas County by Read (1954), who found it only in Elm Fork. L. hijdiana is the third most abundant mussel in Lake Lewisville (but is not common in Area 1); a total of 213 individuals were counted in 12 transects (tables 1, 2). Shells exhibit phenotypic variation in details of structure of the pseudocardinal teeth, but this variation tends to be ontogenetic (changing with age). Rays are absent, present on the entire shell, or restricted to the posterior half. Rays may be single and narrow (about 0.1 mm wide) or may coalesce into stripes (whose widths ap- proach 3 mm). Spacing between rays varies such that 80*^0 of the periostracum may be greenish in contrast to the yellowish horn color of the background. Variation in shell morphology may reflect genetic influence by Lamp- silis luteola (Lamarck, 1819), a species that ranges throughout all of the Mississippi River and southern Can- ada east of the Rock\ Mountains (Burch, 1973:21); /;/- teola intergrades with hijdiana in Louisiana and southern Arkansas (Stansbery, 1983).
Lampsilis satiira (Lea, 1852), the southernmost species ot the Lampsilis ovata (Say, 1817) group, is restricted to westernmost Louisiana and eastern Te.xas (D. H. Stans- bery, personal communication). A single shell was found in Lake Lewisville at station 7 (table 1). This specimen is small (47.6 mm, shell length) and had been dead for several years before reco\er\. The umbo is somewhat higher than those of most L. satura from eastern Texas. The recovered specimen probably represents a remnant population (possibly now extirpated) adapted to a free- flowing stream. Read (1954) reported Lampsilis vcntri- cosa (Barnes, 1823) as rare in Dallas County; this record probably refers to L. satura.
Lampsilis teres (Rafinesque, 1820) was reported b\ Read (1954) as being not ver\' abundant in Dallas Count\ on soft mud substrate, but found in the side of a tight mud bank. Lampsdis fallaciosa Smith, 1899, has been utilized to refer to a smaller form with greenish rays (not found in Lake Lewisville but found in Elm Fork below Lewis\ille Dam during this stud\ ). \alentine and Stans- bery (1971) suggested that Lampsilis fallaciosa may have been replaced by L. teres in Oklahoma during the twen- tieth century after they compared their contemporary collections with those of Isely (1924). White and White (1977) reported the two forms from Lake Texoma in similar habitats but in different arms of the reservoir. L. teres was found at every locality sampled in this study; a total of 76 individuals were counted in 11 transects (table 1).
Leptodea fragilis (Rafinesque, 1820) occurs through- out most of the eastern United States (Valentine & Stans- bery, 1971). Read (1954) found L. jragilis widely dis- tributed in Dallas County in soft sand and muck. L. fragilis was found at all 12 of my sample sites although only 63 individuals were found in eleven transects (table 1). This species was more abundant on sand than on clay substrates, although 1 found L. fragilis in mud at the base of a terrace cutbank in moving water in the Elm Fork above Lake Lewisville.
PotamUus ainphichaenus (Frierson, 1898), is known from the Brazos, Trinity and Sabine Rivers of Texas and westernmost Louisiana (Strecker, 1931). Despite Frier- son's (1898) statement that P. amphichaenus was "one oi the most distinct and remarkable Unios, this taxon is little known today. Specimens of P. amphichaenus from Lake Lewisville can be separated from specimens of Potamiliis ohicnsis (Rafinesque, 1820) from the Red River to the north by the following characters of P. amphichaenus: 1) less compressed laterally; 2) more prominent sinus in the posterior portion of the pallial line; 3) prominent umbo scars; 4) much lower wings, anteriorly and especialK' posteriorly; 5) large gape be- tween the valves, especialK anteriorly; and 6) decreased prominence of pallial line anteriorly.
Potamilus purpuratiis (Lamarck, 1819) occurs in streams from western Tennessee to Kansas, southward to Louisiana, w here it is more common in downstream sites (Valentine & Stansbery, 1971). Read (1954) found it abundant in Elm Fork on gravel, hard clay, mud, and sand. P. purpuratiis is the fifth most common naiad in Lake Lewisville; 88 specimens were counted in 12 tran- sects, and presence was noted in two additional sites.
Toxolasma parvus (Barnes, 1823) is the smallest unio- nid found in this area. T. parvus is found in streams from New York to the Dakotas, southward to Texas and Al- abama (N'alentine & Stansbery, 1971). Live specimens from Lake Texoma were found on silt or soft mud in areas protected from v\ ind disturbance (White and White, 1977). Read (1954) found T. parvus widely distributed in Dallas County on mud bottoms in shallow ponds and sluggish streams. The largest T. parvus that I have seen from Lake Lewisville were 24.9 mm in length. Only six individuals were found at three transects; additional specimens were found at three other sites. T. parvus is a monomorphic (presumabK' monoeicious) species in comparison to the larger, dimorphic (presumably dioe- cious) Toxolasma texasensis (I. Lea, 1857), a species not known from Lake Lewisville.
Truncilla truncata Rafinesque, 1820, is known trom the Mississippi River drainage and westw ard into eastern Texas (Strecker, 1931; Burch, 1973). T. truncata was reported from Elm Fork on soft mud, but occasionally in gravel and sand (Read, 1954). Color of periostracum of Lake Lew isville specimens varies from \ ellow ish brown to dark brown; a few specimens have narrow, faint rays. Sixty-nine individuals were collected from 11 transects.
The bivalve fauna of Lake Lewisville as recorded in this survey consists of 16 species (one corbiculid and 15 unionid species). Amhicma plicata is the most numerous species at all 12 sampling localities and includes well over one-third of the individuals counted. The seven most abundant species in the transects comprise 89.9% of the sample. The seven least common species comprise the remaining 10. 1 % of the sample. Seven species were found at all 12 sampling sites; 1 1 species, 9 or more sites. Except for the two species found at only a single locality, all species were found at fi\ e or more sites. No site contained all species, but all sites had at least nine.
THE NAUTILUS, Vol. 104, No. 1
DISCUSSION Zoogeography
The unionid fauna present -Lake Levusville is typical of the West Gulf Province (Hoback et al 1980, Neck, 198'7a) which includes the area drained b> rivers west and'south of the Mississippi River from the Sab.ne system through the l\.o Grande System. The Trinity Hjver drain- age luts the Miss>ssippi drainage just north of Lake Lewisvilie, where the Red and Trinity Rivers are sepa- rated bv a low divide. Little or no recent f aunal exchange haf occurred because of the very 'i-J^d "umber of mussel species in the Red River. Along the Coastal Plain Se drainages of the Trinity and the Red are separated by the Sabine/Neches system.
\he species present in Lake Lewisvdle represent the •upland" component of those species present in the Trin- ity River Strecker (1931) recorded several species in the lower Trinity (but not the Elm Fork) that are not present in Lake Lewisvilie, because the pre-impoundmen con- ditions of the Elm Fork were not suitable for such large- stream or sand-substrate forms. Species included are StrophUis undulatus (Say, 1817), Fusconma cenna (Conrad, 1838), Megalonaias nervosa (Rafmesque, 1820), Plcctomerus domheyanus (Valenciennes, 1827), Irun- cUla donaciformis (I. Lea, 1828), and Truncilk macro- don (1. Lea, 1859).
INTRA-RESERVOIR DISTRIBUTIONS
Lake Lewisvilie can be divided into three major subdi- visions, which are based upon natural and artificial en- vironmental factors (figure 2). Area I consists of the orig- inal Lake Dallas; this area is underlain by the Woodbine Formation. The substrate presently consists of silty clays which have been deposited over the past 50 years. This area receives sewage outfall from the city of Denton (1980 population-48,063) and probably several small towns farther upstream. Area II consists of the larger part of the new reserxoir portion of Lake Lewisvil e which is underlain by thm silty clay terraces that mantle the Eagle Ford Formation (shale). Area III is the Hickory Creek Arm of the new lake portion, which is underlain by the Woodbine Formation. Substantial portions of this area maintain sandy substrates although the upper reach- es are covered by recently deposited sediments.
The Denton County soil survey provides mtormation concerning soils now covered by Lake Lew^isvil e (Ford & Pauls 1980). Soil types presently inundated by the original Lake Dallas (area 1) include Callisburg fine sandy loam Gowen clay loam, and Navo cla> loam. Soils pres- ently under area II include Altoga silty clay Ferns-Hei- den'clays, and Heiden clay. Area III inundates Bastrop fine sand%- loam, Birome-Rayex-Aubrey complex (sands), Callisburg fine sandy loam, and Crockett fine sandy loam. Examination of the data concerning relative percent- ages of species in the three major subdivisions of Lake Lewisvilie indicates that areas II and III are more siniilar to each other than either is to area I (table 2). This
relationship indicates that, as a factor in thi '^^^ s di tribution, similar period of impoundment (11 and 111) i more important than similar geological substrate (I and 111) \lso important is unrestricted water and organism movement between II and III whereas an old dam struc- ture with a narrow breach exists between and I; no direct connection exists between I and III. Shallower water depths and decreased water quality in area I may be additional factors.
Except the stream species that are found onh near creek entrances and probably do not reproduce within the reservoir {Lampsilis satura and Tritogonia verru- cosa), no species are restricted to only one of these hree subgroups. However, as indicated above, area I stands well apart from the other two in terms of f aunal com- position. For example, the two most com'^^"" ""T't in Lake Lewisvilie (Ambler^ia plicata and Quadrula apiculata) together comprise 55.8% of the entire fauna^ and the corresponding values for areas II and HI are comparable (53.0% and 53.4%, respectively), but m area I these two species comprise 70.6% o the fauna. Area supports the least diverse fauna and is the area mos dominated by species that are tolerant of environmental disturbance by humans. ,. ^u -J
In contrast to dominance by abundant taxa, the third most common species, Lampsilis hydiana is distinctly least common in area I. The other species that are least abundant in area I are Anodonta grandis Lampsilis teres Leptodea fragilis, Potamilus amphichaenus and Truncilla truncata. Potamilus purpuratus is distinctly most common in area I. Arcidens confragosus is more common m areas I and III than in area II; this distribution pattern indicates a preference for sandy substrates, pos- sibly in inflowing streams. Rare in all areas are Quadrula mortoni. Anodonta imbecilis. Toxolasma parvus, and Corbicula fluniinea. .
More individuals and more species occurred in areas with clav rather than sand substrates in Lake Lewisvilie, although a few species are more abundant on sand sub- strates (L.'pf odea /ragi/«, Quadrula mortoni, Arcidens confragosus, and Tritogonia verrucosa) Domination ot the fauna by one or two species was frequent in clay substrates and rare in sand substrates. Such relative abun- dance relationships were also observed at several sites in area II where well-developed sand bars overlay shale bedrock Within areas of clay substrate, uniomds were more common on sites with exposure to wave action. Small sloughs in these areas seldom supported more than a few bivalves.
Faunal Change
Several species reported from the Elm Fork by Read (1954) were not found in Lake Lewisvilie. Obhquaria reflexa Rafinesque, 1820, is a species that requires hard substrates and moderate to fast currents (mqtuma re- flexa was reported from Lake Texoma (White k White, 1977) oiiK- in riprap grasel substrate and substantial wmd- generated xvater movement; this was the onK riverine
R. W, Neck, 1990
Page 23
species found in Lake Texoma. I have found O. rcflcxa in the Elm Fork, below Lewisville Dam; isolated indi- viduals could survive in localK favorable micro-habitats within Lake Lewisville, but periodic drought conditions reduce reservoir elevation and feeder creek flows to such low levels that survival of O. reflexa is unlikely
Only two unionid taxa reported by Strecker (1931) from the Elm Fork at Le\\ isville were not found during this survey. His Qiiadrula houstonensis apparently rep- resented shells referred to Qiiadrula mortoni in this study (see previous discussion). Read (1954) reported Strecker's Fiisconaia flaia uiulata to be rare in Dallas County, and found only in the southeastern section. Several other species were reported b\ Read (1954) in Dallas County, i.e.. Lasmigona costata (Rafinesque, 1S20), Ohovaria subwtunda (Rafinesque, 1820), Pleurobema cordatum (Rafinesque, 1820), Qiiadrula meianevra (Rafinesque, 1820) and Qiiadrula petrina (Gould, 1855). These species are not known to have occurred anywhere in the Trinity River; these records appear to represent misidentifica- tions.
Two species not recorded for the Trinitv Ri\er at Lew- isville by Strecker (1931) have established populations in Lake Lewisville. These species are Anodonta grandis and Anodonta imbecillis; the former has become the fourth most common bivalve in Lake Lewisville. Increase in abundance of these Anodonta has been reported by Murray (1982). Causes of this expansion are not under- stood but probably invoke emploving a large number of fish species as hosts during the glochidial stage of the unionid life cycle (Trdan iT Hoeh, 1982). Read (1954) suggested that fish stocking activities "probabK contrib- uted some species . . . since Strecker," but offered no supporting evidence. Changes in the bivalve fauna of this reservoir are similar to those faunal alterations ob- served in Lake Springfield, Illinois (Parmalee, 1955; Klip- pel & Parmalee, 1979).
Human Utilization of Fauna
An additional human impact upon the unionid fauna of Lake Lew isville was observed during this survey. L'nion- id valve material is being utilized in the cultured pearl industry. The high-purity calcium carbonate of unionid shells (Nelson et al., 1966) is formed into spheres to provide large "seeds" for cultured pearls (Peach, 1983). In August 1978 individual shell collectors were being paid twenty cents a pound (total wet \\ eight of shell and animal) for shells of Amblcma plicaia and Qiiadrula apiculata. At least one collector sold 500 kilograms (1,100 pounds) in a single day. The preferred species was A. plicata. which had to measure about 125 mm in length and could not exhibit worn periostracum on the ridges. Only Amblema plicata from the "new lake" (areas II and III in discussion below) were acceptable as shells from the "old lake" (area I) had thin layers with black or purple coloration. Amblcnm plicata from the "old lake possessed thinner shells than those from other por- tions of Lake Lewisville, shell material was often heavily
sufiused with purple, and shells with white nacre did not possess the bright white nacre seen elsewhere in the res- ervoir. Stansber\ (1971) found that young A. plicata on fine substrates (similar to silted portions of the "old lake" bed) grew more slowly than A. plicata on coarse sub- strates.
Individual collectors were experiencing the effects of resource depletion as suitable unionids were "becoming hard to find." Lhiionids in some isolated coves were rea- sonably safe from collection, but some collectors used boats to get to these sites. Most collectors gathered union- ids in water that was less than two meters deep. Unionids were located visually or tactilely (\\ ith hands or feet). In deeper water, diving equipment was used. Neck (1982b) reported amounts of shell removed from various Texas reservoirs, including Lake Lewisville. The 500 kilograms of A. plicata reported above consist of approximately 1,430 animals with an average weight of 350 grams.
ACKNOWLEDGEMENTS
I thank R. W. Fullington for his field assistance, en- couragement, and general introduction to the intriguing, challenging, and befuddling world of unionids. Discus- sions w ith D. H. Stansbery were useful in understanding the complex problems in determining proper nomencla- ture.
LITERATURE CITED
Burch, J B. 197,3. Freshwater unionacean clams (Mollusca: Pelecvpoda) of North America. Biota of Freshwater Eco- s> stems, Identi. Man. II, U.S. Eiivi. Pro. Agency, 176 p.
Burch, J. B. 197.5. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America, revised ed. Malacological Publications, Hamburg, Michigan, 204 p.
Dou f 11, C. L. and S. D. Breeding. 1967. Dams and reservoirs in Texas. Texas Water Development Board Report 48, 267 p.
Flock, J. M. and J E. L'belaker. 1972 A survev of metazoan parasites in unionid bivalves of Garza-Little Elm Reser- voir, Denton Oiuntv , Texas. Texas Journal of Science 2.3: .381-392.
Ford, A and E. Pauls. 1980. Soil survey of Denton County, Texas. U.S. Department of Agriculture, Soil Conservation Service and Texas .-Agricultural Experiment Station, Wash- ington, DC, 160 p.
Frierson, L. S. 1898. Unio (Lampsitis) aniphichacniis. n. sp. The Nautilus 11:109-110.
Harris, B. B. and J. K. G. Silvey. 1940 Limnological inves- tigation on Texas reservoir lakes. Ecological Monographs 10:111-143.
Hillis, D. M. and J. D. Patton 1982. Morphological and elec- trophoretic evidence for two species of Corbicula (Bival- via; Corbiculidae) in North America. American Midland Naturalist 108:74-80.
Isely, F. B. 1924. The freshwater mussel fauna of eastern Oklahoma. Proceedings of the Oklahoma ,\cademy of Sci- ence 4:4.3-118.
Klippel, W, E. and P E. Parmalee. 1979. The naiad fauna of Lake Springfield. Illinois: an assessment after two de- cades. The Nautilus 94:189-197.
THE NAUTILUS, Vol. 104. No. 1
MauldinV L 1972. The bivalvemollusca of selected Tarrant Countv Texas reservo.rs. Masters thesis, Texas (Ju.st.an
University, Ft. Worth. 83 p. , , , l l Rl Texas
u n 1^72 Fresh water mussels of Lake LBJ, iexas.
"" BnlSi^of t!:.f A^ican Malacolog.cal Union 1972:36-
Murrt H D 1978. Freshwater mussels of Lake Corpus Christi, Texas. Bulletin of the .\mencan Malacolog.cal
Muriv'n a^982: Un.onuls trom Ind.an sUes in McMullen and Live Oak counties, Texas. Bulletn, of the .American Malacological Union 1981:10-11 Murray H D and A. B. Leonard. 1962. Handbook of umomd """muils in Kansas. University of Kansas Museum of Nat- ural Historv Miscellaneous Publication 28 184 P Neck R W 1982a. Preliminary analysis o the ecological zoogeographv of the freshwater mussels of Texas. In: Da- vis ] R. (cd.y Proceedings of the symposium on recent benthological investigations in Texas and adjacent states. Texas Academy of Science, Austin, p. .■>3-42. Neck, R. W. 1982b. A review of interactions between humans and freshwater mussels in Texas. In: Davis, J, R. (ed.)^ Proceedings of the symposium on recent benthological Lestigations in Texas and adjacent states. 1 exas Academy of Science, .Xustiii, p. 169-182. , , , t, ,i,„„i
Neck R W. 1986. Freshwater bivalves of Lake Tawakom, Sabine River, Texas. Texas Journal of Science 38 241-249. Neck R W 1987. Freshwater bivalves of the Baffin Bay drainage basin, southern Texas. Texas Journal of Science
Neck^^R'w ^1989a. Freshwater bivalves of Medina Lake, Texas: factors producing a low-diversity launa. Texas Jour- nal of Science 41.319-325. ,. , , , u 1 Neck R W 1989b. Freshwater bivalves ol Lake Arrowhead ' Texas: apparent lack of local extirpation. Texas Journal of
Science 41:371-377. . i • i ^c
Neck R W and A. L. Metcalf. 1988. Freshwaer bivalves ■ of the lower Rio Grande, Texas. Texas Journal of Science
40:259-268. , , , ,
Neel 1 K 1941 A taxonomic stud> ot (Juadrula qnadruta
'(Rafinesque). Occasional Papers of the Museum Zoologv
of the University of Michigan 448:1-8. Nelson, D. J., T. C. Rains, and J. A. Norris. 1966. High-purity
calcium carbonate in freshwater clam shell Science 152:
1368-1370. , . , . ,
Parmalee, P. W- 1955 Some ecologica aspects ol l^^ "^lad fauna of Lake SpringGeld, Illinois. The Nautilus 69.28-34. Peach J L 1983 Comments on the commercial shell in- dustry, past and present In: Miller, A. L^i';™"Pi'''^'- Re- port of freshwater mussels workshop; 26-2, October 1982. U.S. .'\rmy Engineer Experiment Station, \ icksburg. MS,
p. 84-89.' „ „
Read, L. B. 1954. The I'elecypoda ol Dallas County, I exas
Field & Laboratory 22:35-52. Read L. B. and K. H. Oliver. 1953. Notes on the ecology ot the freshwater mussels of Dallas County. Field & Labo- ratory 21:75-80 Roback, S. S., D, J. Bereza, and M F. Vidrine 1980. De- scription of Ablashesmyia (Diptera:Chironomidae:lany- podinael svmbiont on unionid freshwater mussels (Mol- lusc a BivaKia:Unionacea), with notes on its biology and zoogeography. Transactions of the American Entomolog- ical Society 105:577-619. Smipson. C. T 1914. A descriptive catalogue ot the naiades or pearly freshwater mussels. Detroit, 1540 p.
SmsileN J .V 1893. A prclmunary l.st of the land. Ireshwater and marine Mollusca of Texas, Annual Report Geological Survey of Texas, 1892. 4:299-343. S.nilh 1 \ 1973. Primary productivity and nutrient rela- ■ tionships inGarza-LittleElm Reservoir. Ph D. dissertation.
North Texas University, Denton, 118 p. Stansberv D H. 1971. A study of the growth rate and lon- gevity of the naiad Amblema plicata (Say, 1817) in Lake Erie (Bivalvia: Unionidae). Annual Report ot the American Malacological Union. 1970:78-79. , ^ ■ i ,„J
Stansberv, D. H. 1983. Some sources of nomenclaorial and systematic problems in unionid mollusks. In: \ il er, A. L.. (compiler). Report of freshwater mussels workshop; 2b- 27 October 1982, U.S. Army Engin. Waterways Exp, Sta.. Vicksburg, MS, p. 46-62. Strerker 1 K 1931. The distribution of the naiads or pearls freshwater mussels of Texas. Baylor University Museum Special Bulletin 2, 71 p ... r ,
Trdan R J and W, R. Hoeh. 1982, Eur> topic host use lor two congeneric species ot freshwater '"^"f l* ?'''«■> P^^^^ Unionidae: Anodonto). American Midland Naturalist 108:
Turgeon't^D., A. E. Bogan, E. V. Coan, W. K. Emerson, W. G Lyons, W. L. Pratt, C, F. E. Roper, A. Scheltema, F^ g', Thompson, and J. D. Williams. 198a Common and scientihc names of aquatic invertebrates from the Umted States and C:anada: mollusks. American Fisheries Societv' Special Publication 16:1-277, ValenUne, B. D. and D. H. Stansber> , 1971. An mtroduc ion to the naiads of the Lake Texoma region, Oklahoma, w ith notes on the Red River fauna (Mollusca: Unionidae). Ster- kiana 42:1-40. ,
White, D. S. and S, J. White, 197,, Observa ions on the pelecvpod fauna of Lake Texoma, Texas and Oklahoma, after more than .30 years impoundment. Southwestern Naturalist 22:235-254. Winton, W. M. 1925. The geology ol Denton County, Uni- versity of Texas Bulletin 2544, 86 p.
APPENDIX
Below is a list of collecting localities on Lake Lewisyille, Denton County, Texas, that were used for this study. Numbers are keyed to those in figure 3.
1. Northeast end of -old'- Garza Da.B, west or "old- Lake Dallas side. , ,., , cu .
2. Graveyard Slough, 17.5 km south of Shady Shores
community. r .
S. Willow Grove Park, 1.25 km east ot center ot city
of Lake Dallas. r ■ ■ -ll^
4. East Hill Park, ID km north ot spillway ot LewisvUle
Dam. , , .,, ,f
5. Stewart Creek Park, 15 km north ot spillway of
Lewisville Dam. ,
(,. Ilackberrv Park, east side of large cove m south- eastern portion of Lake Lewisville State Park, 3.6
km west of FM 423. ., , , n i /PMl
7 Little Elm bridge on Farm-to-Market Road (FM) 720, .southeast portion 1.5 km southwest ot com- munity of Little Elm. 8. Cottonwood Park, l.S km south-southeast of Little Elm bridge (FM 720).
R. W. Neck, 1990
Page 25
9. Northeast end of "old" Garza Dam, east or "new" Lake Lewisville Side.
10. Oakland Park, 0.7 km northeast of Copperas Point (across Hickory Creek Arm).
1 1 . Fish-O-Rama (private commercial development ), just
southeast of boundary of Hickory Creek Park, 0.85 km west of IH 35 E. 12. Sycamore Bend Park, 2.9 km west of Interstate High- way 35E.
THE NAUTILUS 104(1 ):26-28, 1990
Page 26
A Reaffirmation of the Nomenclatural Status of Octopus filosus Howell, 1868, the Senior Synonym of Octopus hummelincki Adam, 1936
Ronald B. Toll
Depaitmcrit i)l Biology The L niversil\ of llie South Sc«aneo. T\ 37375 USA
ABSTRACT
Voss (1962) placed Octopus Ituinnicliucki Adam, 1936 into the synonyiiu of Octopus filu.sus Howell, 1868; however, the ma- jority of accounts dealing with this ta.xon since that time have continued to use the junior synonym. The type material of both taxa were reexamined and their nomenclatural histories traced. O. filosus is upheld as the correct senior s\ nonvm and a com- plete s) nonynn is provided
Key words: Octopus filosus. Octopus huiniiuliucki. Octopo-
Hovvell (1868) described Octopus filosa from Santa Cruz Island (= St. Ooi.x in the Virgin Islands). The original description, based on the largest of several live animals Howell had seen, is brief but contains details of body morphometry, arm lengths and the lunnber of adoral, uniseriall) arranged suckers along each arm. Howell (1868:241) commented that the animal was "remarkable for the long and thread-like terminations to the arms . . .". As part of his description of the coloration of the live animal he also noted (p. 241) that "it changes the color of its spots with great rapidity." Howell illustrated the holotype in ventral whole view. In his monographic work on the Octopodinae, Robson (1929) included Oc- topus (Octopus) filosus based .solely on Ilowell's original description and corrected the gender of the specific ep- ithet.
Adam (1936) described Octopus hummelincki from Bonaire, Netherlands West Indies baseil on three syn- types (1 male, 2 females). He noted the presence of a pair of ocelli located between the eyes and the edge of the web. The following year, based on the syntypic series, •Adam (1937) expanded his description and provided photographic whole views of two of the types and iihi.s- traliori:i of the hectocotylus, penis, and fuiuiel organ.
Bused .■!! Howell's description alone, Pickford (1945) plated Octopus filosus into the synonymy of O. vulgaris bccau.se o( i,i r (jf-rception of a lack of a clear morpho- logical distinition between several Floridian specimens
of O. vulgaris with attenuate arm tips that approached the condition for filosus as described by Howell.
Voss (1962), in a report on the cephalopods in the collections of The Academy of Natural Sciences of Phila- delphia, reexamined the holotype ot Octopus filosus and noted (p. 2) the presence of a "faded but distinct ocellus beneath each eye and scattered thin, thread-like papillae on the dorsimi of the head and mantle . Based on this combination oi characters, particularly the ocelli (to which Howell s comment regarding the changing colors of the "spots" probably refers), Voss established O. filosus as the senior synonym of O. hummelincki. Voss further noted that due to the use of the name filosus by both Robson (1929) and Pickford (1945) [an additional ref- erence to this taxon by Pickford (1946) apparently was overlooked], its use could not be suppressed by plenary power [e.g., invocation of the 50 year ride as defined by The International Ciode of Zoological Nomenclature (ICZN, 1985: Art. 79)].
Probably because \'oss' 1962 paper is relatively ob- scure and the nomenclatural situation regarding Octcjpus filosus was mentioned only briefly (one paragraph), .Ad- am s hummelincki has been maintained and used rou- tinely as the specific epithet for this taxon in subsequent accounts. In turn, Howells filosus has been relegated to remain among the nimierous taxa recognized as junior synonyms of O. vulgaris and as such is \ irtualK unknown to a new generation of cephalopod workers.
In order to verify the systematic and nomenclatural disposition of Octopus filosus and O. hummelitu^ki. I reexamined the types of both taxa. The holoty pe of O. filosus (Acadetny of Natural Sciences of Philadelphia A6450) is a female (ML 36 mm) with maturing eggs, now in fair condition. Indications of both ocelli are extant and the manllc. ticad, antl basal portions ot the arms are covered w itli thin papillae. Two oi the three sy ntypes of O. hummelincki were obtained from the Zoologisch Mu- seum-Universiteit Van Amsterdam (1 male with sper- matophores, 1 female, ML 21 and 18 mm, respectively). Both specimens are in excellent condition, the ocelli are distinct, and the mantle, head and arms are ornamented
R. B. Toll, 1990
Page 27
with tall, thin papillae. The oiiK other octopod with similar ocelli fouiKl in the Atlantic Ocean is O. maya V'oss and Solis, 1966, which is entlemic to the Gulf of Campeche, Mexico. In addition it attains large size (to 2.0 kg). My reexamination of the types and the known distribution of ocellated octopods from the Atlantic Ocean support \'oss" contention that O. filo.siis and O. hiim- melincki are s\ non\ ms.
The name hummclincki has appeared in 26 accounts including the original description. Of these, five are species catalogues, three others include Octopus hummeliuchi in a dichotomous key onl\-, and two more cite other papers without the addition of new data. The remaining 16 papers (which include 2 unpublished theses) include new information of a systematic, nomenclatural or bio- logical nature. The name filosus has appeared in four svstematic-tvpe treatments within the last fifty years (Pickford, 1945, 1946; Voss, 1962; Toll, 1988). Addition- ally it is listed, without comment, in the synonymy of O. hiimmeliticki b\ Burgess (1966) and Roper et al. (1984); however, these accounts do not constitute usage as defined in Article 79c(l)i of the ICZN (1985). As previously noted by V'oss (1962), Howell s name cannot be suppressed by the use of plenary power (see ICZN, 1985:Art. 79c). .\s a result, O. filo.siis is here reaffirmed as the senior synonym of O. hummclincki and should be used as such. To be the best of m> know ledge, the com- plete synonynn of O. filosus is as follows:
Octopus filosus Howell, 1868
Octopus filosa Howell, 1868:240.
Octopus filosus, Robson, 1929:146.— Pickford. 194.5:709; 1946: 422.— Voss, 1962:2.— Burgess, 1966:770.— Roper et al. 1984:201.— Toll, 1988:209.
Octopus {Octopus) rugosus (= Octopus vulgaris Lamarck. 1798), Robson, 1929 {pars, only specimen B,M.190;3.9.17,9., fide Pickford. 1946424).
Octopus hummclincki Adam, 19:36:1; 1937:2.5, Pickford. 1945: 745; 1946:414; 1950:1:39.— Voss, 1949:3; 1953:7.'3; 1956: 279; 1962:2; 1968:657; 1975:351; 1976:77 —Rees, 1950: 107.— Burgess, 1966:762.— Voss and Solis, 1966:624 —Pa- lacio, 1977:101.— Cairns, 1976:2.58 —Wodinsky, 1977: 947— Nesis, 1982:302,— Aroclia-Pietri, 1983:37,— Roper et al, 1984:201 —Calow, 1987:360,— Mangold, 1987: 182.— Hanlon. 1988:252 —Toll, i988:209 — \'ecchione et al, 1989:20,
Octopus vulgaris. Pickford. 1945708 [pars, non O. vulgaris Lamarck, 1798).
ACKNOWLEDGMENTS
George Davis and Mary Garback, Academy of Natural Sciences of Philadelphia, loaned the holotype of Octopus filosus. Robert Moolenbeck, Zoologisch Museum-lini- versiteit Van Amsterdam, loaned the syntypes of O. Inim- melincki. Michael Sweene\, Division of Mollusks, Na- tional Museum of Natural History, conducted a computer literature search that aided in the construction of the synonymy. Susan Armentrout, Dupont Library, The Llni- versity of the South, assisted in the acquisition of liter-
ature records. Their contributions are gratefully ac- knowledged. This contribution was supported by a grant from the National Science Foundation (BSR 8508439) and general support for research from the University of the South.
LITERATURE CITED
.Arocha-Pietra F 1983, Cephalopodos del genero Octopus en el area insular del oriente de X'enezuela Master's Thesis, L iiiversidad de Oriente. (Aunana, Wnezuela. 135 p.
.\dam, W. 1936. Notes sur les cephalopods. \4. — Une nou- velle espece d'Octopus (Octopus humnteliucki sp. nov.) des les hides occidentales Neerlandaises, Bulletin du Musee ro\al d Histoire naturelle de Belgique 12(40): 1-3,
■\dam, W 1937 Ceplialopodes des lies Bonaire et Curacao. Capita Zoologica 8:1-29
Burgess, L. A, 1966, \ stud\ of the morphology and biniogv of Octopus hummclincki .\dam, 19:36 (Mollusca: Cepha- lopoda). Bulletin of Marine Science 16(4):762-813-
Cairns, S. D 1976. Clephalopods collected in the Straits of Florida bv the R/V Gerila. 15ulletin of Marine Science 26(2):233-272.
tialow , P, 1987, Fact and theory — an overview. In: Bovle, P, R, (ed, ), Cephalopod life c\cles, volume IP comparative reviews. Academic Press, London, p, ■351-;365.
llanlun. l\ T 1988. Behavioral and body patterning char- acters useful in ta,\ononi\ anil field itlentificati(}n of cepli- ak)pods, Malacologia 29( f ):247-264.
Howell, S, B, 1868, Descriptions of two new species of ceph- alopods. American Journal of Conchologv 3:239-24 i,
ICZN, 1985. International Code of Zoological Nomenclature, 3rd ed. University of California Press, 338 p.
Mangold, K. 1987. Reproduction. /n: Boyle, P. R. (ed.). Ceph- alopod life cycles, volume II: comparative reviews .-Vca- demic Press, London, p. 157-200,
Nesis, K, .N, 1982, Brief svnopsis of certain cephalopod mol- lusks of the world's oceans (in Russian), L',S,S,R,, 358 p,
Palacio. F, J, 1977, .\ stud\ of the coastal cephalopods from Brazil with a review of Brazilian zoogeography. Doctoral Dissertation, University of Miami, Florida. 311 p
Pickford, G. E. 1945. Le poulpe Americain: a study of the littoral Octopoda of the western Atlantic. Transactions of the Connecticut .Acadenu of .\rts and Sciences 36:701- 811,
Pickford, G, E, 1946. .\ review of the littoral Octopoda from the Central and Western Atlantic stations in the collections of the British Museum. .-Vnnals and Magazine of Natural History, Ser. 11, Vol, 13:412-429,
Pickford, G. E. 1950 Tlie Octopoda of the Oxford L'niversity Cayman Expedition. Proceedings of the Malacological So- cieU of London 28(4,5):139-144.
Rees, W J 19.50. Notes on the cephalopods from the Carib- bean. Proceedings of the Malacological Society of London 28(2,3):107-114,
Robson, G, C, 1929, ,A Monograph of the Octopoda, The Octopodinae, British Museum (.Natural Hislorv), London, 236 p.
Roper, C, F, E., M, J, Sweeney, and C E, Nauen, 1984. Cephalopods of the world. Food and .Agriculture Orga- nization (F.\0) Species Catalogue Vol. 3,277 p. FAO Rome.
Toll, R, B. 1988. The use of arm sucker number in octopodid systematics (Cephalopoda: Octopoda). .American Mala- cological Bulletin 6(2):207-21I.
\ ecchione, M., C. F E Roper, and M J Sweeney. 1989
Page 28
THE NAUTILUS, Vol. 104, No. 1
Marine flora and fauna of the eastern United States. Mol- lusca: Ck'phalopoda. .\OA.-\ Teclinieal Report NMFS 73, 22 p.
Voss, G. L. 19-19. Notes on a specimen of Oclopu.s humnic- lincki .Vdani from the Florida Keys. Revista de la Soeiedad Malacologica Carlos de la Torre 7{l):3-5.
\'oss, G. L. 1953. Observations on a living specimen of Oc- topus hummelincki Adam. Nautilus 66:73-76.
\'oss, G. L. 1956. A checklist of the cephalopods of Florida. Quarterly Journal of the Florida .Xcademy of Science 19: 27-1-2S2.'
Voss, G. L. 1962. List of the types and species of cephalopods in the collections of the Academy of Natural Sciences of Philadelphia. Notulae Naturae No. 356, 7 p.
X'oss, G. L. 1968. Oclopods from the R/V Pillsbury south-
western C^aribbean cruise, 1966, with a description of a new species. Octopus zonatus. Bulletin of Marine Science 18:6-4.5-659.
Voss, G. L. 1975. Etuixoctupm, pillslmnjac. nt-w species, (^1'0\- lusca; Ck'phalopoda) from the southern (Caribbean and Sur- inam. Bulletin ol Marine Science 25(,3);346-.352.
\'oss, G. L. 1976. Seashore life of Florida and the Caribbean. Seemann Publishing, Inc., Miami, 168 p.
\oss, G. L. and M. Solis. 1966. Octopus maya, a new species from the Bay of Campeche, Mexico. Bulletin of Marine Science 16(3);615-625.
W'odinsk), J. 1977. Hormonal inhibition ot feeding and death in Octopus: control by optic gland secretion. Science 198: 948-951.
THE NAUTILUS 104(1 ):29-32, 1990
Page 29
Coelatura Conrad, 1853, Caelatiira Conrad, 1865 and Coelatura Pfeiffer, 1877 (Mollusca): A Tale of Two Diphthongs
Gary Rosenberg Arthur E. Bogan Earle E. Spanier
Acaderii) of Natural Sciences 19th and the Parkway Philadelphia, PA 19103, L'SA
ABSTRACT
Coelatura Conrad, 1853 is the valid name for the genus of unionid bivalves emended to Caclatura by Simpson (1900). The family-group name Caelaturinae Model!, 1942 must be corrected to Coelaturinae Modell. Caclatura Conrad, 1865 is the valid name for the genus of barleeid gastropods renamed Actaeonema Conrad, 1865. Coelatura Pfeiffer, 1877, Coela- tura von Martens, 1880, Caelatura Germain, 1921 and Ario- caelatura Germain, 1921 are objective synonyms of Plegma Gude, 191 1, a genus of heli.xarionid gastropods. Confusion among these names has resulted from the difficulty in distinguishing between the "ae and "oe diphthongs when they are printed as ligatures. The ligature for "ae" in some typefaces is used as an "oe' in others. The only way to be sure of an author's intentions is to compare words of known spelling.
Key words: Barleeidae, Actaeonema. Caclatura: diphthongs; Helixarionidae, Plegma: L'nionidae. Coelatura.
INTRODUCTION
During routine curation of the moUusk collection at the Academy of Natural Sciences of Philadelphia, we came across a nomenclatural problem in trying to put speci- mens identified as Caelatura in their proper position in the systematic collection. The name Caclatura was in use in both the Bivalvia and the Gastropoda, and sub- sequent research in the literature revealed further prob- lems with misspellings and emendations affecting taxa in three families. Most of these complications stem from the difficulty of distinguishing the "ae ' and "oe " diph- thongs when they are printed as ligatures, as they were in the texts in which the names considered here were introduced. We have found that the ligature for "ae ' in some typefaces is used as an "oe " in others and that the only way to be sure of an author's intentions is to compare words of known spelling. To sort out the confusion caused by these diphthongs and their ligatures, we rely on the provisions of the Internatiotial Code of Zoological No- menclature (ICZN, 1985). We note at the outset that ae
and DC are regarded as interchangeable for the purposes of homonymy in species-group names (ICZN Article 58), but not in genus-group names, in which a single letter difterence is sufficient to avoid homonymy (Article 56b). We also make use of the ICZN's provisions for deter- mining if subsequent spellings are misspellings or emen- dations, and for determining if emendations are justified or unjustified.
TAXONOMY
Coelatura Conrad (Bivalvia: Unionidae)
In 1853, Conrad named the genus Coelatura, with the single included species Unio aegyptiacus Cailliaud, 1827. He used the spelling Coelatura twice (p. 267, 268), and the distinction between the "oe" and "ae" ligatures is clear in the text. Simpson (1900) used Conrad's genus for a group of African unionid bivalves, but spelled it "Caelatura," (p. 820, S62 and in the index, p. 1004). The instance on page 862 looks like it is spelled with an "oe," because there is little difference between the ae and oe ligatures in the italic typeface in Simpson's work. In- spection of words such as "aegyptiacus" (p. 821), "lae- vigatas" (p. 600) and "coctcstis" (p. 905) shows that he used the spelling "Caclatura" throughout. This consis- tent use qualifies as an intentional emendation (ICZN Article 33b(i)). As there is no evidence in Conrad's text that Coelatura is an original misspelling, the emendation is unjustified and introduces the name Caelatura Simp- son, 1900, which is a junior objective synonym of Coe- latura Conrad, 1853 (Article 33b(iii)), and is also a junior homony m of Caclatura Conrad, 1865 (Gastropoda). Most authors after Simpson incorrectly used the name Cae- latura, rather than Coelatura, exceptions being Yokes (1980:96) and Vaught (1989:124). Modell (1942:190) in- troduced the subfamilial name Caelaturinae based on the emended spelling of Coelatura and Starobogatov (1970:64) used the tribal name Caelaturini. These must
Page 30
THE NAUTILUS, Vol. 104, No 1
be corrected to Coeiaturinae Model), 1942 and Coela- turini Modell, 1942 (Article 35d(ii)).
There is also a question as to the correct spelling of the name of the type species of Coelatiira (Conrad. Cail- liaud (1823-1827) rendered it Vnio aegyptiacu.s in the text (p. 263), but Vnio egyptiacus in the plate caption (pi. 61, fig. 5-6). Most authors have used the spelling found in the text, which was published in 1827, but the plate might have been published before then as the atlas v\as issued in parts between 1823 and 1827 (Sherborn & Woodward, 1901:334). From the available evidence, we cannot prove that the plates were issued before the text, so we retain the spelling "aegyptiacus."
Caelatura Conr.ad (Gastropoda: Barleeidae)
In 1865, Conrad published a catalogue of Eocene and Oligocene shells of the United States, in which he intro- duced the name Caelatura (Conrad, 1865a). He included the species Pasithea sulcata Lea, 1833 and P. striata Lea, 1833 in Caelatura. w hich he placed in the Terebri- dae on page 28. However, he also listed Caelatura in the .Acteonidae on page 35, including only Pasithea striata. Tr\on (1865), the editor of Conrad's paper, stated that Caelatura striata and sulcata both should have appeared on page 35, not on page 28. Later in the year, Conrad renamed Caelatura as Actaeonerna (1865b: 147), citing page 35 and not page 28 of his earlier work, and illus- trating Actaeonerna striata (pi. 11, fig. 2). He did not state why he replaced the name. One might assume that he replaced Caelatura because of its similarity to the prior Coelatura. Iiut Ponder (1983) argued that Conrad meant to restrict the name Caelatura to Pasithea sulcata on page 28 and to provide a new genus for Pasithea striata on page 35. This interpretation is demonstrably incorrect because of Tryon's editorial correction and be- cause Cionrad later (1866:9) included both sulcata and striata in Actaeonerna and no longer used Caelatura. Thus, both Pasithea sulcata and P. striata Lea, 1833 are originally included species in Caelatura. and Aetaeone- rtia must be regarded as a replacement name for it and therefore an objective synonym.
There is also confusion regarding the type species for Caelatura Conrad, 1865. We note that because Caela- tura and Actaeonerna are objective synonyms, the first valid type designation for either is a type designation for both (Article 67h). Some authors (Tryon, 1887:53; Fischer, 1885:779) have given Pasithea striata as an ex- ample of Actaeonerna, which does not qualify as a type designation. It should be noted that Palmer (1937:154) demonstrated that Conrad (1865b) misidentified Pasi- thea striata Lea; the species he figured (pi. 11, fig. 2) is Tuba cancellata Lea, a mathildid. Palmer (1937:68) sug- Ki'sled that P. striata Lea is ba.sed on a turritellid pro- tucoiuh Inspection of the type lot (ANSP 5502) confirms ih:ii tin- /'. striata is not a barleeid or a mathildid, but its aftinitie."; with turritellids are uncertain, as indicated h\ !'' ,1 II if r i ] 985: 1 05). Because Conrad (1865a) cited only Lea ! tvi- Iv^MiTs of P. striata and P. sulcata, his later
(1865b) misidentification of Pasithea striata has no bear- ing on the type species question, a point not realized b\ later authors. Palmer (1937:156) and Moore (1962:98) treated Actaeonerna striata as a species described by Conrad, but this is incorrect, as Conrad was merely in- troducing a new combination. Cossmann (1893:29) stated of Actaeonerna striata (Lea):
II y a lieu de remarquer que ce nest pas cette espece qui est le veritable t\ pe du genre .Actaeonerna. mais Pyramis striata. C>)nrad, c est a dire Pasithea .sulcata ou I espece precedeiite [.Actaeonerna sulcatum (Lea)], de sorte que Toil pent desormais fi.xer, d uue niariiere beaucoup plus certaine, les caracteres de ce genre.
Cossmann thus equated Conrad's misidentification of Pasithea striata with P. sulcata Lea (Conrad had syn- onymized them as Pyramis striata in 1834), but this is incorrect as shown by Palmer (1937). Because Coss- mann s statement is ambiguous, it does not qualify as a type designation (ICZN Article 67c(3)). Cossmann later (1921:49) explicitly cited Pasithea sulcata Lea as the type species of Actaeonerna: this is the first valid t\pe des- ignation that we have found. Ponder (1983:244) recog- nized P. sulcata as the type species of Caelatura, which he placed in the Barleeidae, but incorrectly considered P. striata to be the type of Actaeonerna.
CoEL.\TVRA PfEIFFER (GASTROPODA:
Hellxarionidae)
Pfeiffer (1877:8) also named a Coelatura. type species, by monotypy, "//. coelatura Fer."[= Helix (Helicogena) coelatura Ferussac, 1821], a Mascarene land snail. Von Martens (1880:192) used Coelatura as a subgenus of Pachxjstyla without attributing authorship to the name, but he included "Pachystyla caelatura Ferussac (Helix Helicogena), among other species, so it appears at first that he was referring to Pfeiffer s genus. However, von Martens (1881:74) cited himself as having introduced Coelatura in ISSO. Therefore, we select Pachystyla cae- latura (Ferussac) [= Helix (Helicogena ) coelatura Ferus- sac, 1821], by reason of virtual tautonomy. as t\'pe species of Coelatura von Martens, 1880, making it an objective synonym of Coelatura Pfeiffer, 1877. Coelatura Pfeiffer non Conrad was replaced b\ Plegnia Gude, 1911 and is now placed in the Helixarionidae. (Helicarionidae is a misspelling based on the unjustified emendation of He- lixarion Ferussac, 1821 to Helicarion b\ Ferussac (1822) (Kennard, 1942).)
Some authors (e.g.. Zilch, 1959:308) consider Pfeiffer's Coelatura to have been emended to "Caelatura" by Fi.scher. However, Fischer spelled Coelatura correctly in the text (1883:461); it is misspelled in the index (1887: 1339), as noted by Schuize et al. (1927:482), but this cannot be construed as an emendation, and has no no- menclatural standing. The first author to have emended Pfeiffer's Coelatura to Caelatura appears to be Germain (1921:103), apparently because he thought that the cor-
G. Rosenberg et al., 1990
Page 31
rect spelling of the type species was Helix caelatura, not Helix coelatura as given by Pfeiffer (1877:192). How- ever, this is an unjustified emendation because Pfeiffer's Coelatura cannot be considered an incorrect original spelling based on evidence in Pfeiffer's text (ICZN Article 32c(ii)). Further complicating matters, Germain (1921: 461), who was unaware of Gude's Plegrna, introduced Ariocaelatitra as a replacement for Pfeiffer's name when he realized that it was preoccupied. Thiele (1931:615) and Viader (1937:79) considered Ariocaelatura and Plegma to be distinct genera although they are objective synonyms. Wenz (1947) introduced the name Psciido- caelatura for Ariocaelatura "Thiele" non Germain, with type species Pachystyla scalpta (von Martens, 1877). Wenz s name is preoccupied by Pseudocaclatura Ger- main, 1921 and was replaced by Dancea Zilch, 1960.
There has been confusion as to the correct spelling of the specific name of Helix (Helicogena) coelatura be- cause of inconsistencies in Ferussac's work (1819-1832). The species was illustrated on plate 28 (fig. 3, 4), the caption of which was published on 6 April 1821. A second reference to the plate appeared later that year in Ferus- sac 1821a (p. 30 of the quarto edition, p. 34 of the folio), which was published 26 Ma\ 1821 (dates from Kennard, 1942:109, 1943:122). In the plate caption, the specific name is spelled "coelatura," but from inspection of other words in the captions in the same italic t\ peface, it is apparent that the typesetter often substituted ligatures, using oe for ae. For example, acavae (pi. 33, 35), acavoe (pi. 25, 30, 32, 34, 36); columellatae (pi. 11, 15, 17), colurriellatoe (pi. 15, 17, 25, 32); and perforatoe for per- foratae throughout. The vernacular descriptor that Fer- ussac gave this species in the caption is "ciselee." mean- ing carved or sculpted, corresponding in meaning to the Latin caelatura. However, coel- is sometimes used as an alternate spelling for the Latin root cael-, so it cannot be proven from the evidence of the original publication that "coelatura" is a misspelling. In 1821a (p. 30) and 1827 (p. 302) Ferussac used the spelling "caelatura." but these do not qualify as emendations as the spelling ap- pears only once in each work. The spelling "caelatura" is repeated four times by Deshayes in Ferussac and De- shayes (1850:162), which qualifies as an emendation. (Deshayes continued Ferussac's work after the latter s death in 1836). In the complete set of plate captions for the work (Ferussac and Deshayes (1851 in 1819-1851)) the spelling "coelatura" recurs, presumabK' copied from the original plate captions. Both spellings have been used with about equal frequency in the literature, as shown in the synonymy by Germain (1921:103). The two most recent references to the species that we have found (Zilch, 1959:308; Groh and Griffiths, 1987:39) use the spelling "coelatura." Because "coelatura" has priority, cannot be proven to be an original misspelling, and does not threat- en nomenclatural stability. Helix (Helicogena) coelatura Ferussac, 1821 is the correct citation for the t\pe species of Plegma. Helix caelatura Deshayes in Ferussac and Deshayes, 1850 is an unjustified emendation and an ob- jective synonym of it.
Summary
We have established the status of the following names; valid names are listed first followed by objective syn- onyms:
Coelatura Conrad. 1853 (Bivalvia: Uiiionidae) [type species, by moiiotypy, Unio aegyptiacus C^ailliaud, 1827] + Caelatura Simpson, 1900 Caelatura Conrad, 186.5a (Ga.stropoda: Barleeidae)[t>pe species, b\ subsequent designation of Cossmann (1921:49), Pasi- thca sulcata Lea, 1833]
+ Actaconcma Conrad. 1865b /'/r^'/iuj Glide, 1911 (Gastropoda; Helixarionidae) [type species, b\ monot>py, "H. coelatura Fer. " = Helix (Helicogena) coelatura Ferussac, 1821] -I- Coelatura Pfeiffer, 1877 + Coelatura von Martens, 1880 -I- Caelatura Germain, 1921 -I- Ariocaelatura Germain, 1921
ACKNOWLEDGEMENTS
We thank Audi Garback for bringing this problem to our attention. Kenneth C. Emberton and two anonymous reviewers provided helpful comments, Robert Robertson aided with translations, and Kenneth J. Boss and P. K. Tubbs advised on interpretation of the ICZN. This work was made possible b\ NSF Grant BSR-8911074 for col- lection support in the ANSP malacology department.
LITERATURE CITED
Cailliaud, F 1823-1827. Voyage a Meroeet au Fleine Blanc, vol. 4, 415 pp., 1 pi , atlas vol. 2, 75 pi
Conrad, T. A. 1834. Fossil shells of the Lower Tertiar\ or Eocene period. In: Morton, S. G. Synopsis of the organic remains of the Cretaceous Group of the United States Key & Biddle, Philadelphia, p. 3-8, appendix
Conrad, T, .\. 1853. A synopsis of the family of naiades of North America, with notes, and a table of some of the genera and sub-genera of the family, according to their geographical distribution, and descriptions of genera and sub-genera. Proceedings of the Academy of Natural Sci- ences of Philadelphia 6:243-269.
Conrad, T, A. 1865a. Catalogue of the Eocene and Oligocene Testacea of the United States, American Journal of Con- chology 1:1-35 [published 25 February 1865].
Conrad, T. A. 1865b Descriptions of new Eocene shells of the United States. American Journal of Conchology 1:142- 149, pf 10-11 [published 15 April 1865].
Conrad, T. A. 1866. Check list of the invertebrate fossils of North America. Eocene and Oligocene. Smithsonian Mis- cellaneous Collections 200, iv -(- 41 p
Cossmann. M. 1893. Notes complementaires sur la faune Eocenique de r.\labania. Annales de Geologic et de Pa- leontologie 12:1-51, pi. 1-2.
Cossmann, M. 1921. Essais de paleoconchologie comparee, vol. 12. Paris, 349 p. pi, a-d, 1-6.
Ferussac, A. E. 1819-1832. Histoire naturelle generale et particuliere des mollusques terrestres et fluviatiles. Atlas, 162 pi. [See Kennard (1942) for dates of plates and ac- companying text.]
Page 32
THE NAUTILUS, Vol. 104, No. 1
Ferussac, A. E. 1821a. Tableau systematique de la famille des lima9on.s, cochleae. Paris. [Quarto edition, 111 p.; folio 114 p. See Kennard (1942) for dates of publication of signatures.)
Ferussac, .'\. E, 1827. C^atalogue des especes de mollusques terrestres et fluviatiles, recueillies par M Rang, offic. de la marine roy., dans un voyage aux grandes hides. Bulletin des Sciences Naturelles et de Geologic 10:298-307, 408- 413.
Ferussac. A. E. and Desliayes, G. P. 1819-1851. Histoire naturelle generate et particuliere des mollusques terrestres et fluviatiles, 2 vols. [For collation see Kennard (1942).]
Fischer, P. 1880-1887. Manuel de concliyliologie et de pa- leontologieconclnliologique. Librairie F. Savy, Paris, x.xiv + 1369 p . 23 pi , frontispiece.
Germain, L. 1921. Faune malacologique terrestreet fluviatile des lies Ma.scareignes. Gaultier et Thebert, Angers, iv + 495 p., 13 pi.
Groh, K. and O. Griffiths. 1987. Africa and Adjacent Islands. In: Parkinson, B., J. Hemmen, and K Groh. Tropical land- shells of the world. Crista Henuiien, Weisbaden, Federal Republic of Germany, p. 30-39.
Gude, G. K. 1911. Further note on preoccupied molluscan generic names and a proposed new genus of the family Helicidae. Proceedings of the Malacological Society of London 9:361-362.
International Commission on Zoological Nomenclature. 1985. International code of zoological nomenclature, third edi- tion, adopted by the XX General .Assembly of the Inter- national L'nion of Biological Sciences. London, x\ + 338 p.
Kennard, A. S. 1942. The llUtoire and Prodrome of Ferussac. Proceedings of the Malacological Societv of London 25: 12-17, 105-118.
Kennard, A. S. 1943. Notes on the nomenclature of the Mas- carene non-marine Mollusca. Mauritius Institute Bulletin 2:115-136.
Lea, 1, 1833 Contributions to (Jeology. Carey, Lea and Blan- chard, Philadelphia, 227 p., 6 pi.
Modell, II. 1942. Das natiirliche System de Najaden. Archiv fiir Molluskenkunde 74:161-191.
Moore, E. J. 1962. Conrad s Onozoic fossil marine mollusk type specimens at the Academy of Natural Sciences of Philadelphia, Proceedings of tfie Academy of Natural Sci- ences of Philadelphia 114:23-120
Palmer, K. \\ W. 1937. The Claibornian Scapliopoda, Gas- tropoda and dibranchiate (Cephalopoda of the southern United States. Part I. Bulletins of American Paleontologv 7(32): 1-548.
Pfeiffer, L. 1877. Leber die systematische Anordiiung der Helicaceen. Malakozoologische Blatter 24:1-14, 75-84.
Ponder, W. F. 1983. Review of the genera of the Barleeidae
(Mollusca: Gastropoda: Rissoacea). Records of the .Austra- lian Museum 35:231-281.
Ponder, VV. F. 1985 (1984). .K re\iew of the genera of the Kissoidae (Mollusca: Mesogastropoda: Rissoacea). Records of the Australian Museum, Supplement 4, 221 p.
Schulze, F. E., W. Kiikenthal, and K. Heider, 1927, \omen- clator animalium generum et subgenerum 2(6):477-636. Preussischen Akademie der Wissenschaften, Berlin.
Sherborn, C. D. and B. B. Woodward. 1901. Dates of pub- lication of the zoological and botanical portions of some F'rench vovages. — Part II. .Annals and Magazine of Natural History (7')8:333-336.
Simpson, C, T. 1900. Synopsis of the naiades, or pearK fresh- water mussels. Proceedings of the United States National Museum 22:501-1044, pi. 18.
Starobogatov, Y. I. 1970 Fauna mollyuskov i zoogeografi- cheskoe raionirovanie kontinental nykh vodoemov zem- nogo shara. Akademiya Nauk SSSR, Zoologicheskii Insti- tut, Leningrad, 372 p,
Tliiele, J 1931, Haiidbuch der s>stematischen Weichtier- kunde. Part 2. Gustav Fischer, Jena, p. 377-778.
Tryon, G. W. 1865. Correctionsandadditions to Mr. Conrad's catalogue of Eocene Mollusca, published in the 1st number of this journal. .American Journal ol Concholog) 1:191- 192. [Published 1 October 1865]
Tryon, G. W. 1887. [lanthinidae, Trichotropidae.Scalariidae.] Manual of Conchology 9:33-111, pi. 7-18.
X'aught, K. C. 1989. .\ classification of the living Mollusca. American Malacologists, Melbourne, Florida, xii + 195 p.
V'iader, R. 1937. Revised catalogue of the testaceous Mollusca of Mauritius and its dependencies Mauritius Institute Bul- letin l(2):xiv -I- 111 p., 1 map.
Yokes, H. E. 1980. Genera of the BivaKia: a systematic and bibliographic catalogue (revised and updated). Paleonto- logical Research Institute, Ithaca, New York, xxvii + 307 p.
von Martens, E. 1877. Ubersicht der wahrend der Reise um die Erde in den Jahren 1874-1876 auf S. M. Schiff Gazelle gesammelten Land- und Siisswasser-Mollusken. Monats- bericht der Koniglichen .Akademie der Wissenschaften zu Berlin, p. 261-291, pi. 1-2.
von Martens, E 1880 Mollusken In. Mobius, K., F. Richters, and E. v Martens. Beitrage zur Meeresfauna der Insel Mauritius und der Seychellen. Gutmann'schen Buchhan- dlung, Berlin, p. 181-336, pi. 19-22.
\()n Martens, E. 1881. Mollusca. Zoological Record 17:1-104 (for 1880).
VVenz, W. 1947. Zur Taxonoinie tier Euth\ neiua, .Archi\ fiir Molluskenkunde 76:36.
Zilch, .A. 1959-1960. Gastropoda: Eutlnneura In: Schinde- wolf, O. H. (ed). Handbuch der Palaozoologie, vol. 6(2). Gebriider Borntraeger, Berlin, p. i-xii, 1-834.
THE NAUTILUS 104(1):33, 1990
Page 33
Ediiardiis Pilsbry, 1930, a Subgenus of
Praticolella Martens, 1892
(Gastropoda: Stylommatophora: Polygyridae)
Kenneth C. Emberton Leonard Richardson
Department iit Malacology Academy of Natural Sciences 19th & the Park\va\ Philadelphia, PA 19103
ABSTRACT
The purpose of this note is to correct a iiomenclatural error that occurs in the literature.
Pilsbry (1930:315) erected Eduardus as a section of the sub- genus Pohjgyra {Daedalochila) Beck, 1837, with P. marten- siana Pilsbr>', 1907, as the type and onl\ member Later, in a brief note, Pilsbry (1937) transferred P. maricnsiana to the genus Praticolella Martens, 1892, based on the genital anatom\ of specimens collected in 1934 at "Ingenio Agua Buena, near Tamosopo, S.L.P., ' Mexico. Pilsbry (1956:30) continued this assignation in a faunal paper on northern Mexico Both the note and the faunal paper were apparently overlooked by Zilch (1960:580, fig. 2036), who figured Praticolella (Eduardus) mar- tensiana, but incorrectly gave the name as Daedalochila (Ed- uardus) martensiana. This error was carried over into Rich- ardson's (1986) catalog of species of the Polygyracea. Both Eduardus and Einisa. which was introduced on the same page, were omitted from Clench and Turner's (1962) "Names Intro- duced b\ Pilsbr>. "
The shell of P. martensiana. with its depressed spire and relatively open umbilicus, is quite distinct from those of all other known members of Praticolella. It seems advisable there- fore to retain Eduardus as a subgenus, pending a generic re- vision, which is much needed although not presently planned by either author of this note Thus. Praticolella comprises four subgenera: Eduardus. Farragutia Vanatta, 1915; Filapex Pils- bry, 1940; and Praticolella scnsu stricto. Pilsbr\ (1940) listed Filapex as a section, which is equivalent to a subgenus (Inter-
national Commission on Zoological Nomenclature, 1985: Ar- ticle He).
LITERATURE CITED
Clench, W. J. and R. D. Turner. 1962. New names introduced by H A. Pilsbry in the Mollusca and Crustacea. Academy of Natural Sciences of Philadelphia, Special Publication No. 4:1-218,
International C^ommission on Zoological Nomenclature. 1985. International Code of Zoological Nomenclature, Third Edition. University of California Press, Berkelev and Los .Angeles, p. 1-338,
Pilsbry, H. A. 1930. Anatomy and relationships of some .\mer- ican Helicidae and Pol) g\ ridae. Proceedings of the .\cad- emy of Natural Sciences of Philadelphia, 82:303-327.
Pilsbr\. H. A. 1936. Praticolella martensiana. Nautilus 49: 140
Pilsbry, H. A. 1956. Inland Mollusca of northern Mexico. III. Polygyridae and Potadominae. Proceedings of the .Acad- emy of Natural Sciences of Philadelphia 108:19-40.
Richardson, L. 1986 Pol\g\racea: catalog of species (parts 1, Polvgvridae; 2, Corillidae; 3, Sagdidae). Tryonia 13:1- 139, ]'-40, 1-38,
Zilch, A 1960. Gastropoda. Teil 2. Euthyneura. Band 6 In: Schindewolf, O. H. (ed). Handbuch der Palaozoologie. Gebrueder Borntraeger, Berlin, p 1-834
Page 34
THE NAUTILUS, Vol. 104, No. 1
News and Notices
SMITHSONIAN FUNDS FOR MALACOLOGY STUDFNTS
The Division of Mollusks, Department of Invertebrate Zoology, National Museum of Natural History, Smith- sonian Institution annoimces the availability of the Rose- water Fellow Award (up to $1,000) to be awarded to graduate students of systematic malacology. This award provides support for students conducting systematic stud- ies of Mollusca (leading to publication) who require ac- cess to collections and libraries of the Division of Mol- lusks, National Museum of Natural History. Funds can be used for travel, subsistence, and research costs. Inter- ested students should submit a succinct proposal (1-2 pages), including budget with indication of any matching funds, and a supporting letter from faculty advisor(s). Application deadline is July 15, 1990. Award(s) will be announced on August 15, 1990.
BACK ISSUES OF THE NAUTILUS
Volumes 101-103 of THE NAUTILUS are available from the business office at $25.00 per volume. The Supplement to volume 103 [Catalogue of the superfamily Cancellar- ioidea Forbes and Haiiley, 1851 (Gastropoda: Proso- branchia) by R. E. Petit and M. G. Harasewych] is avail- able separately at $15.00.
A small and ever-changing supply of earlier volumes is also maintained. Prices may vary depending on age and condition of individual issues. Inquiries are invited and want lists will be maintained.
INSTRUCTIONS TO AUTHORS
THE NAUTILUS publishes papers on all aspects of the biolog) and systematics of mollusks. Manuscripts de- scribing original, unpublished research as well as review articles will be considered. Brief articles, not exceeding 1000 words, will be published as notes and do not re- quire an abstract. Notices of meetings and other items of interest to malacologists will appear in a news and notices section.
Manuscripts: Each original manuscript and accompa- nying illustrations should be submitted in triplicate. Text must be typed on one side of 8'/2 x H inch white paper, double spaced throughout (including literature cited, ta- bles and figure captions), with at least 1 inch of margin on all sides. All pages must be numbered consecutively. If printed on a word processor, the right margin should be ragged rather than justified. Authors should follow the recommendations of the Council of Biology Editors Style Manual, which is available from the Council of Biology Editors, Inc., 9650 Rockville Pike, Bethesda, MD 20814, U.S.A. The first mention of a scientific name in the text should be accompanied by the taxonomic au- thority, including year. Latin names and words to be printed in italics must be underlined; leave other indi- cations to the editor. Metric and Celsius units are to be used.
The sequence of sections should be: title page, abstract page, introduction, materials and methods, results, dis- cussion, acknowledgements, literature cited, tables, fig- ure captions, figures. The title page should include the title, author "s name(s) and address(es). The abstract page should contain tfie title and abstract, which should sum- marize in 250 words or less the scope, main results and conclusions of the paper. The abstract may be followed by a maximum of 8 key words. All references cited in the text must appear in the literature cited section and vice versa. In the literature cited section, all authors must be fully identified and listed alphabetically. Follow a recent issue of THE NAUTILUS for bibliographic style, noting that journal titles must be unabbreviated. Infor- mation on plates and figures should be cited onl\ if not included in the pagination. Tables must be numbered and each placed on a separate sheet. A brief legend must accompany each table. Captions for each group of illus- trations should be typed on a .separate sheet and include a key to all lettered labeling appearing in that group of illustrations.
All line drawings must be in black, high quality ink, clearly detailed and completely labeled. Photographs must be on glossy, high contrast paper. All figures are to be consecutively numbered (figs. 1, 2, 3, ... , NOT figs. la. lb, Ic, . . . NOR plate 1, fig. 1 . . .). Illustrations must be arranged in proportions that will conform with the width of a page (6% inches or 171 mm) or a column (3'/4 inches or 82 mm). The maximum size of a printed figure is 6% by 9 inches or 171 by 228 mm. All illus- trations must be fully cropped, mounted on a firm, white backing, numbered, labeled and camera ready. The au- thor s name, paper title and figure number(s) should ap- pear on the back. Original illustrations must be between one and two times the desired final size. It is the author's responsibility that the line weight and lettering arc ap- propriate for the desired reduction. Original illustrations will be returned to the author if requested. Color illus- trations can be included at extra cost to the author.
Voucher Material: Deposition of type material in a recognized public museum is a requirement for publi- cation of papers in which new species are described. Deposition of representative voucher specimens in such institutions is strongly encouraged for all other types of research papers.
Processing of Manuscripts: Upon receipt, every manu- script is acknowledged and sent for critical review by at least two referees. These reviews serve as the basis for acceptance or rejection. Accepted manuscripts are re- turned to the author for consideration of the reviewers' comments. A finalized version of the manuscript is re- turned to the editor and sent to press. Two sets of proofs are sent to the author for correction. Changes other than typesetting errors will be charged to the author at cost. One set of corrected proofs should be sent to the editor as soon as possible. Authors with institutional, grant or other research support will be billed for page charges at the rate of $60.00 per printed page.
An order form for reprints will accompany the proofs. Reprints may be ordered through the editor.
Manuscripts, corrected proofs and correspondence re- garding editorial matters should be sent to: Dr. M.G. Harasewych, Editor, Division of Mollusks, NHB stop 118, National Museum of Natural History, Smithsonian In- stitution. Washington, DC 20560, USA.
THIS PUBLICATION IS PRINTED ON ACID-FREE PAPER.
rHE NAUTILUS
Volume 104, Number 2 September 6, 1990 ISSN 0028-1344
A quarterly devoted to malacology.
Marine Biological Laboratory LIBRARY
S
SEP 1 7 1990 \
Woods Hole, Mass. j
EDITOR-IN-CHIEF Dr. M. G. Harasewych Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
ASSOCIATE EDITOR Dr. R. Tucker Abbott American Malacologists, Inc. P.O. Box 2255 Melbourne, FL 32902
CONSULTING EDITORS Dr. Riidiger Bieler Department of Malacology Delaware Museum of Natural History P.O. Box 3937 Wilmington, DE 19807
Dr. Robert T. Dillon, Jr. Department of Biology College of Charleston Charleston, SC 29424
Dr. William K. Emerson
Department of Living Invertebrates
The American Museum of Natural
History
New York, NY 10024
Mr. Samuel L. H. Fuller 1053 Mapleton Avenue Suffield, CT 06078
Dr. Robert Hershler Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
Dr. Richard S. Houbrick Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
Mr. Richard I. Johnson Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, OH 43210
Dr. James H. McLean Department of Malacology Los Angeles County Museum of Natural History 900 Exposition Boulevard Los Angeles, CA 90007
Dr. Arthur S. Merrill % Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Ms. Paula M. Mikkelsen Harbor Branch Oceanographic Institution, Inc. Ft. Pierce, FL 33450
Dr. Donald R. Moore
Division of Marine Geology
and Geophysics
Rosenstiel School of Marine and
Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149
Mr. Richard E. Petit
P.O. Box 30
North Myrtle Beach, SC 29582
Dr. Edward J. Petuch Department of Geology Florida Atlantic University Boca Raton, FL 33431
Dr. David H. Stansbery Museum of Zoology The Ohio State Universitv Columbus, OH 43210
Dr. Ruth D. Turner Department of Mollusks Museum of (Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Geerat J. Vermeij Department of Geology University of California at Davis Davis, CA 95616
SUBSCRIPTION INFORMATION The subscription rate per volume is US $25.00 for individuals, US $35.00 for institutions. Postage outside the United States is an additional US $4.00 for surface and US $12.00 for air mail. All orders should be accompanied by payment and sent to: THE NAUTILUS, P.O. Box 3430, Silver Spring, MD 20901.
Change of address: Please inform the publisher of your new address at least 6 weeks in advance. All communications should include both old and new addresses (with zip codes) and state the effective date.
THE NAUTILUS (ISSN 0028- 1344) is published quarterly by Trophon Corporation, 8911 Alton Parkway, Silver Spring, MD 20910.
Second Class postage paid at Silver Spring, MD and additional mailing offices.
POSTMASTER: Send address changes to: THE NAUTILUS P.O. Box 3430 Silver Spring, MD 20901
THE
CONTENTS
N AU T I L U S
Volume 104, Number 2
September 6. 1990
ISSN 0028-1344
Review of the genus Colina H. and A. Adams, 1854
(Cerithiidae: Prosobranchia) 35
Richard S. Houbrick
|
Harold G. Pierce |
Two unusual gastropods from Late Pliocene lakes in northeast Nebraska |
53 |
|
Edward J. Petuch |
A new molluscan faunule from the Caribbean coast of Panama |
57 |
|
H. Lee Fairbanks |
Morphological comparisons of the species of Megapallifera (Gastropoda: Philom>cidae) |
71 |
|
M. G. Harasewych |
Ovophagy in Anachis avara (Say, 1822) (Gastropoda: Columbellidae) |
76 |
Marine Biological Laboratory \ LIBRARY
SEP 1 7 1990
Woods Hole, Mass.
THE NAUTILUS 104(2):35-52, 1990
Review of the Genus Colina H. and A. Adams, 1854 (Cerithiidae: Prosobranchia)
Richard S. Houbrick
Department of Iinertehrate Zoology National Museum of Natural Histor\ Smithsonian Institution Washington. DC; 20560, USA
Page 35
ABSTRACT
The t\'pes of all nominal Colina species were examined as well as numerous specimens in museum collections. Based on this material and gross anatomical study of one species, a diagnosis of the genus is presented. Fourteen species-level taxa have been proposed; of these, three species are recognized herein: the t\ pe-speeies. Colina macrostoma Hinds. 1844. Colina selccta MeKill and Standen. 1S98. and Colina pinguis {A. .^dams. 18.541, The radulae of Colina macrostoma and Colina pinguis were examined and anatomical features of the latter species were studied for character analysis. Lectotypes for Colina cos- tatum and Colina pinguis are selected, and Colina gracilis is determined a nomcn dubium. The genus Colina is assigned to the family Cerithiidae. subfamily Cerithiinae. near the genera Biltium. Clypeomorus. and Cerithium.
INTRODUCTION
One of the more poorly known genera of the Family Cerithiidae Ferussac, 1819, is Colina H. and A. Adams, 1854. Shells of members of this genus differ considerably from those of all other cerithiids in having an overall pupoid, fusiform, frequently-slender shape, and a mark- edly constricted body whorl. The genus is not species- rich, but the alpha taxonomy of the group has never been comprehensively reviewed. Colina species are not well- represented in museum collections and some appear to be relatively uncommon in their natural habitats. To date, their radular morphology has been obscure and nothing has been published about their soft anatomy.
Colina has been assigned to or grouped with a com- posite mixture of cerithiid and cerithiopsid genera, and its placement among these groups has varied among au- thors. For example, H. and A. Adams (1856:286) listed Colina after Cerithium Bruguiere, 1789, and Vertagus Schumacher, 1817. Tryon (1883:247-248) considered it to be a subgenus of Cerithium, placing it between Cer- ithioderma Conrad, 1860 and Cerithiella Verrill, 1882. This allocation was obviously based on convergent shell resemblance, as Cerithioderma is in Calyptraeoidea, while Cerithiella is now considered a member of the Ceri- thiopsoidea (see Marshall, 1980:85-86). Cossmann (1889:
61) believed that the protoconch of Colina was unlike those seen in Cerithium species and suggested that it was more like that of Lovenella Sars, 1878. a cerithiopsoide- an. He subsequently pointed out that the name Colina was preoccupied and considered it to be a subgenus of Bezanconia Fischer, 1884, a fossil taxon, close to Atax- ocerithium Tate, 1894 (Cossmann, 190690). Fossil Be- zanconia species look very much like living species of Ataxocerithium, a group which has been excluded from the Cerithiidae and shown to belong to Cerithiopsoidea (see Houbrick, 1987a). Both Thiele (1929:212) and VVenz (1940:758-759) placed Colina within the Cerithiidae, but grouped it with Ataxocerithium and other non-cer- ithioidean taxa. Colina was placed after Vertagus but before Campanile by Fischer (1884:680), thus further linking it with non-cerithioidean taxa {Campanile is no longer regarded as a cerithioidean. but has been raised to superfamilial rank, Campanioloidea [see Houbrick, 1989]). Thiele (1929:212) proposed hchnocerithium as a subgenus of Colina, but anatomical examination of the type-species of the former taxon shows it to be a txpical Cerithium representative (Houbrick. pers. obs. ).
As seen in the taxonomic historx presented above, the composite systematic concept of Colina has oscillated between cerithioidean and cerithiopsoidean assignments due to the failure of authors to recognize convergent shell characters in members of both superfamilies. \ comprehensive study (Houbrick, in press) of the alpha taxonomy of Cerithium Bruguiere, sensu lato, led to questions about Colina, as several species have been at- tributed to both genera Examination of the types of the nominal species of Colina and study of some preserved anatomical material has revealed a number of interesting characters and has prompted this review, which should expose the genus to more comprehensive studies.
MATERIALS AND METHODS
The types of all nominal Colina species were examined and specimens in major museums were studied to de- termine the range of variation in shell sculpture. As few preserved samples of Colina species were available for
Page 36
THE NAUTILUS, Vol. 104, No. 2
anatomical sIikIn. the radiila and opcrculuni ot some species remain unkiumn. No live specimens ol Colina were e.\amine(l Despile repeated attempts to obtain live- collected, well-preserved specimens, the only available material was unrelaxed, ethanol-preserved specimens of Colina pinguis. from eastern Africa. Unfortunately, no adult females were found during the course of this study, and the pallia! oviducts could not be .studied.
Specimens were dissected under a Wild M-8 dissecting microscope. Radulae and protoconchs were studied using an Hitachi Scanning Electron Microscope.
.Abbreviations: AMS, .Australian Museum, Sydney; ANSP, Academy of Natural Sciences, Philadelphia; BMNM, British Museum (Natural History); BPBM, Bern- ice P. Bishop Museum, Hawaii; DMNH, Delaware Mu- seum of Natural History; LACM, Los Angeles County Museum of Natural History; MCZ, Museum of Com- parative Zoology; MNHNP, Museum National d'Histoire Naturelle, Paris; NMW, National Museum of Wales; USNM, United States National Museum; WAM, Western Australian Museum.
As mentioned earlier, morphological characters de- rived from soft part anatomy are known chiefly from ethanol-preserved specimens of Colina pingins and from one dried sijecirnen of C. macrosionia; thus, what follows is incomplete and may be inaccurate, as some anatomical features have been distorted due to poor preservation.
SYSTEMATIC REVIEW
An overview of the taxonomy, morphology, and the ecol- og> of Colina species is presented below. A discussion of the relationship of this genus to other cerithiids and a review of the species follows.
Colina W and A. .Adams, 1S54
Colina H. and \ .\danis, 1854:2SH, pi oO, fig. 2 (type species by o.d.: Cchthium macwstonia Hinds, 1844); Tryon, 1883: 247-248. pi, 69, fig. 52; 1887:141; Fischer, 1884:680; Coss- mann, 1889:61-62; Thiele, 1929:212; Wenz, 1940:758.
Colinia H. and .A. .Adams, 1858 [emended] Cossmann, 1906: 90-91 (not C.oliuia Nuttaij, 1832, Aves); Wenz, 1940:758.
Diagnosis: Shell small, elongate, usually decollate, and pupoid with gibbous midwhorls; teleoconch sculptured with axial ribs; body whorl constricted. Columella with strong internal plait. Aperture narrowly ovoid and with expanded outer lip. Operculum corneous, ovoid, pauci- spiral, with subterminal nucleus. Mantle edge dorsalK fringed with papillae. Foot large, having epipodial skirt fringed with papillae and large, posterior operculiferous lobe; sole with well-developed propodial mucus gland tih! massive centrally located, metapodial mucus gland •!i longitudinal slit-like opening. Alimentar\ system -,•; rising taenioglossate radula with scjuarish rachidian (■" '.'i i.inf esophageal gland, and stomach with gastric blii'-l'i jr .1 ,tyln sac. Osphradium bipectinate, very broad CtcdiJi uin <-.\tending length ol mantle cavity and com- prising i :ig digit .ip filaments. Pallial gonoducts open.
Epiathroid nervous system w ith long cerebro-pedal con- nectives.
Synonymic Remarks: The name Colina was thought to be a secondary homonym of the bird taxon, Colinus Goldfuss, 1820; by Cossmann (1906:90-91), who emend- ed the name to Colinia (preoccupied by Colinia Nuttall, 1832, also Aves). This action was unnecessary, as Article 56b of the International Code of Zoological Nomencla- ture (ICZN, 1985) clearly states that even if the differ- ence between two genus-group names is only one letter, these two names are not homonyms; thus, Colina is a valid genus group name, and is not preoccupied
Colina macrostoma (Hinds, 1844) (figures 6-44)
Ccrithium macruatuma Hinds, 1844:27, pi. 26, ligs. 1 1-12 (llo- lotype [probable]: BMNH 1989181, 10.1 mm; Type local- it\ : Borneo); Sowerb\ , 1855:877, pi. 184, fig. 219; Sowerby in Reeve, 1865: pi 17, fig. 118; Tryon, 1887:142, pi. 26, figs. 10, 13-15 {in part).
Culina pupiformis A. Adams, 1853:176, pi. 20. fig. 14 iHolo- type: BMNH 1989182, 13.6 mm. T\ pe locality: Duma- guete, Philippines).
Ccrithium (Colina) costatum .A. Adams in Sowcrbv, 1855:126, pi. 184, fig. 220(Lectot\pe, here selected: BMNH 1989180, 11.1 mm; Type locality: not given (not CU'rithium costa- tum Defrance, 1817).
Ccrithium pupacjorme A, Adams. Sowerby. 18.55:877, pi. 184, fig. 221; Sowerby in Reeve, 1866, pi. 17, fig. 122.
Ccrithium costifcrum (cmd. pro costatum .\ .Adams) Sowerb\ . 18,55:896, pi. 184, fig, 220; Sowerbv in Reeve, 1866: pi. 17, fig. 117,
Colina gracilis H. Adams, 1866:150-151 (Type material not located, no figure given: nomen dubium).
Colina pijgmaca H. Adams, 1867:308, pi. 19, fig. 20 (Holotype: BMNH 1878.1.28.32, 10.1 mm; Type locality: Borneo).
Ccrithium coarctatum Sowerby, 1866: pi. 12 [supplementary], figs. 321-322 (Type material not found; Type locality: not given; Sowerb) s fig, 32 selectetl to represent le'ctot\pe)-
Cerithium (Colina) macrostoma Hintl.s, E, .\. Smith. 1884:66- 67,
Ccritliiuni rigens Bayle, 1880:244 (replacement name for Cer- ilhiuiu costatum .A, .Adams, 1855). Tryon, 1887:142.
Description: Shell (figures 6-41): Shell narrowly tur- reted, elongated, comprising about 15 inflated whorls. Protoconch small, comprising one smooth whorl. Upper teleoconch whorls sculptured with 3 spiral cords and numerous fine axial striae. Adult teleoconch whorls sculp- tured with about 4 major spiral cords and 4 minor spiral cords; central cord frecjuentK' large, carinate; subsutural cord with minute axial pleats. Spiral cords crossed by 12-13 weak to strong axial ribs, forming cancellate sculp- ture; intersections commonly beaded Suture moderately impressed, distinit Boil) whorl strongly constricted, elongated, .sculptured with broad, flattened spiral cords and weak axial striae and incised lines. Aperture ovately elongate with moderateK elongate, slightK reflexed ca- nal, concave columella; lliiring outer lip of aperture, thick and smooth at edge. Shell color [linkish tan to light brow n.
R. S. Houbrick, 1990
Page 37
cmg
Figures 1-5. Anatomical features of Colina pingttis. 1. ventral aspect of the sole of foot, showing crescent shaped propodium, fringing papillae and operculiferous lobe of the epipodial fringing skirt, and two mucus glands, bar = 1 mm; 2. right lateral aspect showing mantle edge and headfoot, bar = 3 mm; 3, longitudinal cross section through middle of foot showing columella muscle and metapodial mucus gland; 4. frontal section through propodium showing details of propodial mucus gland; 5. section of osphradium showing layout of pectens. Abbreviations: cm — columellar muscle; cmg — columellar muscle groove; d — duct of me- tapodial mucus gland; dp — duct of propodial mucus gland; eps — epipodial skirt; f — flap covering slit into propodial mucus gland; mmg — metapodial mucus gland; mp — mantle papilla; ms — metapodial slit; op — operculum; opl — operculiferous lobe; p — papilla; pmg — propodial mucus gland; s — sole of foot; sn — snout.
with dark brown spiral lines and bands, and blotched with white, especially on beads.
Radula (figures 42-44): Raduiar ribbon small, short, about one-seventh the shell length. Rachidian tooth (Fig- ure 44) with square basal plate having slight median posterior projection and weak lateral fold at each pos- terior base; cutting edge with median, spade-shaped main cusp flanked on each side by 2-.'3 pointed denticles. Lat- eral tooth (figure 44) with rhomboid basal plate having
short lateral extension and wide central pillar with small pustule; cutting edge with large pointed main cusp, one inside denticle and 2-3 outside pointed denticles. Mar- ginal teeth (figures 42, 43) spatulate having wide bases and curved tips w ith long pointed main cusp, 2-3 inner pointed denticles and 2 outer denticles; outer marginal tooth same but lacking outer denticles.
Animal: Dried specimen from Japan (ANSP 240281) with papillate mantle edge, moderately long snout and
Page 38
THE NAUTILUS, Vol. 104, No. 2
R. S. Houbrick, 1990
Page 39
long, thick cephalic tentacles. Foot long, somewhat tu- bular in shape, having narrow sole.
Synonymic remarks: The type lot of Cerithium macro- stoma Hinds originally consisted of five specimens glued to boards The one surviving specimen is labeled "prob- able holot\pe": it is the figured specimen in Sowerby s Thesaurus Conclnjliorum (fig. 219) and in Conchologia Iconica (pi. 17, figs. 118a,b). The type of Colina gracilis H. Adams has not been found. Considering that the de- scription is ambiguous and no figure was presented, it seems prudent to regard this ta.xon as a nomen duhium. H. Adams (1866) noted its close resemblance to Colina macrostoma and later remarked (1866:308) that "The species I lately described as C. gracilis 1 find has been since described by Mr. G. B. Sowerby under the name of C. coarctata. ' Although the type of Cerithium coarc- tatum has not been found, Sowerby s figures adequately represent it, and indicate close resemblance to Colina macrostoma. The many synonyms of this species lia\e resulted from the failure of authors to appreciate the wide range of intraspecific shell characters. Recognition of the variability of Colina macrostoma was first noted by E. A. Smith (1884:66-67), who suggested that Colina costata, C. costiferum. C. pygmaea, and C. pupiforn}is were all ". . . mere variations of one and the same shell, ' and who noted the variation in whorl number and shape due to loss of the upper spire. While it may be difficult to believe tliat extreme phenotypes such as the shells of the nominal species shown in figures 6-41 are conspe- cific, examination of many museum specimens and the types of the nominal species listed in the above synonymy reconfirms E. A. Smith's conclusion.
Colina selecta Melvill & Standen, 1898 (Figures 46, 47), is conchologically ver>' close to Colina macrostoma, and may be a synonym of this species, but this remains unresolved, due to lack of comparative material.
Discussion: This species is highly variable in shell shape and sculpture. Older adult shells have a truncated, pu- pate appearance due to decollation of early whorls and erosion of the apex, and these look very different from nondecollate shells (see figures 37, 38, 40, 41). Some specimens lose more of the early whorls than do others. When the apex of the spire has been broken off, the animal closes the opening with a spiral plug and fre- quently this is inset deeply within the old whorl (figures 33-36).
There is a great intraspecific difference in whorl num- ber and in the number and strength of the axial ribs. A range of phenotypes, from those having extremeK slen- der shells (figures 8-10, 13-16, 19, 20) to those with highly inflated midwhorls with wide axial ribs on their
shells (figures 29-34, 37, 38), may occur within the same population. Shell sculpture is highly variable, but gen- erally comprises 4-6 spiral cords of which the dominant one frequently forms a keel on the middle of the whorl. Spiral cords are crossed by 12-14 strong axial ribs pre- senting an overall cancellate appearance (figures 19, 20, 39). Some phenotvpes have small nodes at the intersec- tions (figures 8, 9,' 13, 14, 17, 18, 22, 23). The subsutural spiral cord has many minute axial pleats. The body whorl cords are flat and weakly sculptured with about 10 in- cised spiral lines (figure 39). There is seldom any axial sculpture on the bod\ whorl except for the axial pleats beneath the suture. Shell color varies from light tan to pinkish-brown, the body whorl and especially its incised spiral lines, frequently being brown. These show through on the inside of the outer apertural lip.
Shells from Japan and the Philippines (figures 6-25) are slender and higliK elongate, while those from Aus- tralia and the Indian Ocean (figures 26-41) tend to be shorter, broader, and more pupate. These shorter phe- notypes have been given the names Colina pupijormis and Colina pygmaea. Initially, I was inclined to recog- nize these nominal species as a subspecies of Colina mac- rostoma because their shorter, more stocky shells tend to occur in more southern and western geographical re- gions. However, there are intergrades (figure 39), and non-decoUate specimens from these regions bridge the gap. Specimens from these parts of the range are fre- cjuently badly eroded and uncommon in collections: when more material is available for study, this putative geo- graphic trend in morphology may become better doc- umented. Currently, there is insufficient material to un- equivocally resolve this issue, and it seems best to be conservative and regard these nominal taxa as pheno- t\pes of Colina macrostoma.
There is little information about the specific micro- habitat of Colina macrostoma. In Japan and the Phil- ippines, the habitat appears to be shallow, subtidal sea grass beds (IISNM 343907, 273627). Although spa\\-n and larvae of Colina macrostoma are unknown, its proto- conch morphology (Figure 28) suggests a lecithotrophic type of development (see Robertson, 1974; Jablonsky and Lutz, 1980).
Geographic distribution (figure 45): This species ap- pears to be confined to the Indo- West-Pacific, having a distribution from Japan south through the Philippines, Indonesia and tropical Australia, and into the Indian Ocean as far west as eastern India and Ceylon.
Specimens examined: INDIA: W of Mandapam, Cull of Mannar (ANSP 302283). CEYLON: (USNM 91248).
Figures 6-25. Colina macrostoma (Hinds) 6-7. iectotype of Cerithium macrostoma Hinds, Borneo, BMNH 1989181, length 10.1 mm; 8-10. Port Douglas, Queensland, Australia, LACM 116089, length 18.9 mm; 11-12. Iectotype of Cerithium (Colina) Costatum A, Adams, BMNH 1989180, length 11.1 mm; 13-18. Sulu Archipelago, Philippines, LACM 76874, length 15.5 mm. 165 mm, 11.6 mm, respectively; 19-20. Shimoda, Shizuoka Pref., Japan. L,'\C:M 9:3102, length 19 0 mm; 21. holotype of Colina pupijormis A. .^dams, Dumaguete, Philippines, BMNH 1989182, length 1'3.6 nmi; 22-23. Sulu Archipelago, Philippines, L.-KCM 76874, length 15 :3 mm; 24-25. Honshu, Japan, ANSP 240281, length 12.0 nmi
Page 40
THE NAUTILUS, Vol. 104, No. 2
R. S. Houbrick, 1990
Page 41
Figures 42-44. Colina macrostoma. scanning electron micrographs of radula 42. portion of radula with marginal teeth spread open, bar = 40 /urn; 43. portion of radula with folded marginal teeth, bar = 40 iim, 44. detail of lateral and rachidian teeth, bar = 20 Mill.
BORNEO: (type-specimen, Borneo (BMNH). JAPAN: Shirahama, near Shimoda, Kii, Shizuoka Pref., Honshu (LACM 93102); Ikenedan (BPBM 229662); Shirahama, Kii, Shizuoka Pref., Honshu (MCZ); Oshima. Osumi, Honshu (USNM 343907, 273627, MCZ); Hachijo Shima, off Tokyo (ANSP 2402S1, 240158, 240223); Kanada Bav, Kyushu (USNM 91115); Banda, Boshiu (ANSP 65275, MCZ); Hirado, Hizen, Kvushu (USNM 343908, ANSP 1217). RYUKYUS: Loo Choo Ids (ANSP 195629); Ada Village, Kumigami Prov., Okinawa (ANSP 320695). PHILIPPINES: Laminusa, Siasi, Sulu Archipelago
(LACM 76874), WESTERN AUSTRALIA: North West Cape Reef, Yardie Creek to Tantabiddi (WAM 1020- 84); Mangrove Bay, North West Cape (WAM 1021-84). QUEENSLAND, AUSTRALIA: Grays Bay, Bovven, Queensland (AMS CI 17180); 2 mi N of Ellis Beach, Queensland (AMS CI 17178); Mission Beach, Queensland (AMS C17177); Clump Pt, N Mission Beach, Queensland (BMNH); Dunk Id, Queensland (ANSP 140135. 140136); Four Mile Reef, 4 mi S of Port Douglas (AMS CI 17175); headland between Kings & Queens Beaches, Bowen (AMS C117169, 117173); Lindeman Ids, N of Mackay (AMS
Figures 26-41. Colina macrostoma (Hinds). 26-27. holotype of Colina pygmaea H. Adams, Borneo, BMNH 1878.1.28.32, length 10 1 mm; 28. protoconch and early whorls, AMS C117177, total length 3 mm; 29-30. N. Mission Beach, Queensland, .Australia, BMNH, length 10.7 mm; 31-34. Ellis Beach, Queensland, Australia, AMS C117178, lengths 95 mm, 99 mm, respectively; 35- 36. N. Mission Beach, Queensland, Australia, BMNH, length 8 3 mm; 37-38. Ellis Beach, Queensland, Australia, AMS C117178, length 9.6 mm; 39. Port Douglas, Queensland, Australia, AMS CI 17177, scanning electron micrograph, length 9.8 mmm; 40-41. Hinchenbrook Id., Queensland, Australia, AMS, length 9 3 mm
Page 42
THE NAUTILUS, Vol. 104, No. 2
20- 40- 60" 8tf
Figure 45. Geographic distribution of Colina species.
100"
120
140
160°
C178174); Hinchenbrook Id, Queensland (AMS); Thurs- day Id, Torres Strait, Queensland (BMNH 8212697).
Colina selecta Melviil & Standen, 1898 (figures 46, 47)
Colina selecta Mclvill & Standen, 189«:31, pi. 1, fijr. 2 (Holo- t\pe: Manchester Museum, 1.5 1 ini'i; Type locality; Ma- dras, India).
Description: Shell (figures 46, 47): Shell turreted, elon- gate, narrow comprising about 12 convex whorls having overall cancellate sculpture. Protoconch unknown. Early teleoconch whorls with 3-4 four spiral cords. Adult te- leoconch whorls scul[)tured with 5 spiral cords crossed by 14-1,5 axial ribs and with siibsutural cord pleated axially. Suture impressed. Body whorl elongate, con- stricted, with about 10 flattened spiral cords, but lacking axial sculpture. Aperture narrow, ovate, with slight si- phonal constriction and short, reflected canal and smooth outer lip. Clolumella concave with slight callus. Shell color %\hitish-gray to tan. Operculum, radula and animal un- known.
l)!-.rii';si<in: This species is based solely upon the type 'uii (i;il .'im prising two specimens. It is mori^hologi- i :iil ■ loM- i(, Molina macroslotna with v\hich it is geo- grapl.'. .liv svnipatric In India. Mclvill & Standen (1898: 31 pon.i, .! iiiif th, resemblance of Colina selecta to Coli-
na macrostoma (cited as C. taeniatum), but noted that it was not as pupiform in shape, and not as nodulated transversely. Colina selecta has highly cancellate sculp- ture, a greater number of axial ribs, and an unflaring aperture. Considering the extreme phenotypic variation observed in Colina macrostoma, it is not unreasonable to suggest that Colina selecta may be mereK another variation of the former species. However, Colina selecta is known only from a few specimens, and as no specimens of Colina macrostoma with intermediate shell sculpture bridging the gap have been seen, it seems best to regard Colina selecta as a good species until evidence is pre- sented suggesting otherwise.
Geographic distribution (figure 45): The range of this species is limited to the t\pe localit\ in Madras, India.
Specimens examined: INDI.\: Madras (type-specimen, Manchester Museum); Krusadi, Madras (paratope, NMW 55158).
Colina pingttis (A. .\dams, 1854) (figures 48-76)
C'cnlhimu pin^uis .\ .\daMis, IS.")l:S(i ll.frtn(\ |H-, Iktc des- ii;natcd: HMNII 1989200 1. 17 7 nun, l paralectotypes; BMNH 19S99()() 2-5; Type loc,ilit\ I'hilippines [in error]; here cdirrclcil lo Cape Natal. .Snulli Africa);
R. S. Houbrick, 1990
Page 43
Figures 46-4-7. Colina selecta Mel\'ill & Standen. 46. liolotvpe, Madras, Manchester Museum, 15,1 mm length; 47. paratype,
NMW 55158, 10,5 mm length.
Cerilhinm pinguc A, Adams, Sowerby, 1855:877, pi, 184, fig. 217; Sowerby in Reeve 18Wi: pi. 17, fig. 121.
Cerithium (Colina) pingue A. Adams. Tryon, 1887:141, pi, 26, figs, 8,9,11; Abrard, 1942:61, pi. 6, fig. 28.
Cerithium taeniatum Sowerby in Reeve, 1866: pi. 17, fig. 119 (Holotype: BMNH 1989199; Type-locality: Cape Natal, South Africa, 16 mm (not Cerithium taeniatum Quo\ and Gaimard, 1834:11.3); Sowerby, 1866: pi. 17. fig, .320; 1866, pi. 12 [supplementar\], fig. 320,
Cerithium contraclum Sowerb\, 1855:877, pi, 184, fig, 218 (Holotype: BMNH 1907.10,28,129, 17 mm; Type localit> : unkown; not Cerithium contractum Bellardi, 1850); Sow- erby in Reeve, 1866: pi. 17. fig. 120.
Cerithium crumena Bayle, 1880:245-246 (replacement name for Cerithium contractum Sowerb), 1855).
Colina perimensis Jousseaume. 1930:28.5-286 (replacement name for Cerithium taeniatum Sowerby, 1866).
Description: Shell (figures 48-73): Shell moderately elongate, decollate (adults usualK' missing 3-4 vvhoris), adults with plug-like apex; upper whorls v\ith concave outline, conve.x, swollen middle whorls, and constricted body whorl. Shell shape pupate due to decollation of early whorls and formation of secondary apex. Proto- conch comprising about 2 imsculptured smooth w horls with slightly sinuous apertural lip. Early teleoconch whorls sculptured with 3-4 spiral striae; teleoconch whorls con- cave, pendant; penultimate whorl convex. Adult whorls
with overall sculpture of fine spiral striae and incised lines and with 10-14 large axial plicae or ribs on lower half. Body whorl large, elongate, tightly constricted, and weakly sculptured w ith subsutural plicae and spiral cords. Suture moderateK impressed. Aperture narrowly ovoid with short, broad weakly reflexed anterior canal, and smooth dilated outer lip. Columella concave, smooth w ith slight wash at aperture; 2 internal columellar plaits ex- tending up pillar. Shell color white, with large tan to brown blotches or maculations; thin brown stripes on body whorl appearing as stripes or brown checks at ap- erture inner lip; axial ribs frequently white. Periostracum tan, thin. Operculum (Figures 67, 68) corneous, ovate, paucispiral with eccentric nucleus.
Animal (figures 1-5): Body comprising about four whorls. Long, wide columellar muscle 2 whorls in length; anterior columellar muscle with 2 deep grooves (figure 3, cmg) corresponding to columellar plaits of shell pillar. Ophalic tentacles moderately elongate, but fat and very broad with large peduncular eyes (figure 2); snout mod- erately elongate, bilobed at tip. Inhalant siphon slightly protruding, with large papillae at edge and darkly pig- mented undersurface. Foot large; epipodial skirt fringed with many short papillae (figure 1, p) and having large, posterior operculiferous lobe (figure 1, opl); sole with
Page 44
THE NAUTILUS, Vol. 104, No. 2
; i.n.rrs 4-8-55. Colina pinguis and types of nominal species. 48-49. lectotype of Cerithium pinguis A. Adams from <^ape Natal a, RMNH 1989200/1, 17 7 mm length; 50-51. paralectotype of Cerithium pinguis. Cape Natal, South Africa, BMNH _ f n.S mm length; 52-53. holotype of Cerithium taeniatum Sowerhy, Cape Natal, South Africa, BMNH 1989199, Iti.w niiT. lei.gln, 54-55. liolotvpe of Cerithium amtraclum Sowerhy, BMNH 1907.10.28.129, 17.0 mm length.
R. S. Houbrick, 1990
Page 45
Figures 56-66. Colina pinguis, showing variation in pattern and sculptural niorpholi)g> . 56-57. Port Alfred, South Africa, DMNH 16073, 17.3 mm length; 58. shell cut axially to show weak columellar fold, 16.0 mm length; 59-60. Port Alfred, South Africa, DMNH 16073, 18.5 mm length; 61-62. Djibouti, Djibouti, MNHNP, 18.5 mm length; 63-64. Port Alfred, South Africa, DMNH 16073, 16.9 mm length; 65-66. Djibouti, Djibouti, MNHNP, 15.8 mm length.
Page 46
THE NAUTILUS, Vol. 104, No. 2
R. S. Houbrick, 1990
Page 47
Figures 74-76. Colina pinguis, scanning electron micrographs of radula (Port Alfred, South Africa, DMNH 16073). 74. general view of ribbon with marginal teeth spread open, bar = 6 nm; 75. half row, bar = 6 ^m; 76. detail of lateral and rachidian teeth, bar = 40 nm.
Figures 67-73. Colina pmguis. scanning electron micrographs of shell and operculum (Oman, BMNH) 67-68. attached and free sides of the operculum, respectively, bar = 0 9 mm; 69. early juvenile whorls (protoconch missing), bar = 0.5 mm; 70-73. lateral and apical views of decollate shell apices, showing broken original shell and replacement plugs, bar (70, 72) = 0.9 mm, bar (71, 73) = 0.,5 mm.
Page 48
THE NAUTILUS, Vol. 104, No. 2
large, centrally-located, slit-like metapodial mucus gland (Figure 1, mmg) extending deeply within central foot. Propodial mucus gland (figures 1, 4, pmg) crescent shaped, slit-like, extending deeply into front edge of foot, and overlain b\ thin epithelial flap.
Radula (figures 74-76): Radula about one-fifth the shell length. Rachidian tooth (figure 76) with square basal plate ha\ing small central bottom projection and with slightly raised fold at each lateral edge; cutting edge convex, with large, central spade-shaped cusp flanked on each side with 2, sometimes 3 small, blunt denticles. Lateral tooth (figure 76) rhomboid-shaped with mod- erate lateral extension and having wide posterior pillar- shaped extension with small bead; cutting edge com- prising small inner denticle, large pointed cusp and 3 small outer denticles. Marginal teeth (figure 76) spat- ulate, broad at middle, curved at tips; inner marginal tooth with 2 inner denticles, long pointed central cusp and 2 outer denticles; outer marginal tooth same but lacking outer denticles.
Synonymic remarks: This species has four synonymous names. The type lot of Colina pinguis comprises five specimens, which vary greatly in sculpture and shape. The largest specimen (figures 48, 49), which corresponds to Sowerby's (1855) fig. 217 in the Thesaurus, also ap- pears to be the figured specimen of Colina pinguis in Conchologia Iconica (1866: pi. 17, fig. 121) and is here designated as the lectotype. The second largest specimen of the type lot (figures 50, 51; paralectotype) was figured by Sowerby (1866) in Conchylogia Iconica on the same plate (fig. 120), and named Cerithium contractum, but this name is preoccupied. The holotype of Colina taenia- tum (name preoccupied) is a weakly sculptured, non- decollate specimen (figures 52, 53) of Colina pinguis. which shows some brown spiral stripes not seen in the type lot. Both Colina taeniatum and Colina contractum were given replacement names by Jousseaume (1930) and Bayle (1880), respectively.
Discussion: Colina pinguis is easily distinguished from its congener, Colina macrostoma, by its larger, wider, and heavier shell. Its upper whorls are concave and pen- dant, sculpture is not usually as cancellate as in Colina macrostoma, and it never attains the narrowly elongate form of that species. There is no geographical overlap between the two species.
Examination of many lots of Colina pinguis from South .\frica and from more northern locations reveals consid- erable sculptural variety within populations (see figures 48-66). Moreover, older, decollate individuals (figures 48-55) have a fatter, more .squat aspect than younger, more fusiform individuals with retained spires (figures 56-66). Specimens from the Red Sea (figures 61, 62, 65, 66) and northwestern Indian Ocean appear to be more darkly colored than those from South Africa.
This species, commonly recorded from South Africa. pr .1 inix occurs in suitable habitats all along the north- eustern I'ncan coast, which is more poorly known. Spec- imens In; tn Kr-rva indicate that southern populations are
probably continuous with more northern ones in the Red Sea. Colina pinguis lives gregariousK in lower midtidal pools, chiefly in clumps of coralline algae (Kilburn & Rippey, 1982:54). A label accompanying specimens from Oman in the British Museum (Natural Histor\ ) collection also cites coralline algae as the habitat. Bosch and Bosch (1982:49) record Colina pinguis occurring on sand and algae at low tide in Oman.
The spawn of Colina pinguis has been briefly de- scribed and illustrated b\ Kilburn and Rippey (1982:55, fig. 20), who recorded that it is deposited among branches of coralline algae, and consists of a gelatinous mauve string. Their depiction of the egg ribbon shows that it is small, about 10 mm in length, and contains few, mod- erately large eggs. This feature, plus the unsculptured protoconch, and the patchy, nearly disjunct geographic distribution of the species suggest a direct type of de- velopment, but this needs confirmation.
Fossil records: This species has been recorded from the Pleistocene of Somalia (Abrard, 1942:61, pi. 6. fig. 28).
Geographic distribution (figure 45): Colina pinguis occurs along the eastern African coast from South Africa north to Kenya, and then jumping north to the Red Sea, the Gulf of Oman, and Persian Gulf, extending eastward to Pakistan. The single records from Suez and the Persian Gulf need reconfirmation.
Specimens examined: RED SEA: Suez, Egvpt (USNM 23227). AFFARS & ISSAS: Djibouti (MNHNP). OMAN: Muscat (USNM 798223); Wadi Haart, near Salalah (BMNH); Slud, near Salalah (BMNH). PERSIAN GULF (MNHNP). IRAN: Chah Bahar (MNHNP). PAKISTAN: Manani Rocks, Karachi (BMNH). KENYA: Mombassa (USNM). SOUTH AFRICA: Albany (USNM 97995); Port Alfred, Eastern Cape (USNM 186801, DMNH 16073); Port Gonubie (USNM 845781); Cape Natal (BMNH).
DISCUSSION
Shell Morphology and .4natomy: There are several notable diagnostic shell features of Colina species. This genus is easily identified by its unusual fusiform, fre- quentK- slender, pupate shell ha\ing inflated midwhorls and a highly constricted bod\ whorl. EarK whorls are concave in outline, while adult midwhorls are inflated and usually sculptured with large axial ribs. The bod> whorl is constricted and narrow, relativel\- weakK sculp- tured, and has an elongate, o\ate aperture. In addition, the upper \\ horls are frequently decollate and a second- ary apex (figures 70-73) is added as a plug, enhancing the pupate shape.
The truncated apex is a distinctive feature of the shell of Colina species, .\lthough decollation and formation of a secondary apex occurs in shells of Cerithidea species, family Potamididae (Houbrick, 1984), this phenomenon is not seen in other genera of the Cerithiidae nor in members of other cerithioidean families.
The protoconch of Colina macrostoma (figure 28) is smooth, comprises one whorl, and is indicative of direct
R. S. Houbrick, 1990
Page 49
development. It differs totally from the elaborately sculp- tured protoconchs of litiopids (see Houbrick, 1987b: 12, figs. S, 10) and is unlike those of most Bittium and Cer- ilhiiim species that have pelagic veliger larvae. However, Cerithium species with direct development have pro- toconchs similar to those in Colina (see Hout)rick, 1973; 1974). Cossmann's (1889:61) assertion that the proto- conch of Colina was unlike those of cerithiids and more like those of cerithiopsids such as LovcncUa. is probably due to his mistaken notion that the secondary ape.x of decollate Colina individuals (see figures 70-73) he ex- amined was the real protoconch.
EarK whorls of Colina species are sculptured with three to four spiral cords (figure 69), the two anterior ones being strongest. Kilburn and Rippey (1982:55, fig. 19) noted that "Juveniles resemble very narrow, very high-spired trochids, with a flattened base and short, sharp siphonal spout." Immature Colina pingttis shells have a concave outline, and look very much like adult Trochocerithium species (see Houbrick, in press).
Of the three Colina species recognized herein, Colina pinguis has the largest, widest shell (figures 48-66). In contrast, Colina macrostoma (figures 6-41) commonly is highly elongate and slender, some morphs attaining almost a nail-like shape (figures 8-10, 14-16, 19-20). This species also has the most variable shell sculpture within the genus. The shell of Colina selecta (figures 46, 47) has a sculpture that closely resembles Colina macrostoma, but is more finely cancellate.
Anatomy: Most of the anatomical knowledge about Co- lina species has been derived from an examination of Colina pinguis; thus, anatomical characters may be aug- mented and/or redefined as the soft parts of other species become known.
Externally, the animal has an overall certithiid aspect and comprises about four w horls. The visceral coils con- sist of a typical digestive gland and gonad, a stomach about one whorl in length, and a moderately large kid- ney. The columellar muscle (figure 3, cm) is long and broad, extending nearK two whorls in length, and has two deep anterior grooves (figure 3, cmg) that corre- spond to the columellar plaits of the shell. The long, broad columellar muscle seen in Colina species does not occur in Bittium species or in litiopids. The dorsal mantle edge is fringed with papillae (figure 2, mp).
The large foot has an epipodial skirt (figure 2, eps) fringed with papillae along its lateral edges and has a large, posterior papillate operculiferous lobe (figure 1, opl), similar to that seen in many Bittium species. The operculum (figure 1, op) overlies the operculiferous lobe. The foot is probably longer and more slender than de- picted in figure 1, and the epipodial papillae more ten- tacular in living snails. The epipodial papillae are short (at least in preserved specimens), and do not appear to be as elongate as in litiopids. In this respect, they are more like the epipodial papillae observed in some Bit- tium species (Houbrick, pers obs. ). The operculigerous lobe of the posterior epipodium of Colina species is also
similar to that observed in Bittium species (see Marcus & Marcus, 1963:75, fig. 80; Houbrick, pers. obs.).
The propodium is crescent shaped (figure 1) and has a long papilla at each side followed by the smaller pa- pillae (figure 1, p) of the epipodial skirt. The leading edge of the propodial sole has a deep slit along its leading edge overlain by a thin propodial flap (figures 1, 2, 4, f). This slit leads into a large deep propodial mucus gland (figures 1, 4, pmg) in the front of the foot. The mor- phology of the propodial mucus gland of Colina pinguis is nearly identical to that of litiopid and Bittium species.
The sole of the foot (figures 1, 3, s) is highly glandular, having many transverse furrows and a deep longitudinal slit (figures 1, 2, ms) beginning at the middle of the foot and extending back to its posterior edge. The slit marks the entrance to a massive metapodial mucus gland (fig- ures 2, 3, mmg) having a large duct (figure 3, d) that extends deep into the headfoot to the pedal ganglia. Similar metapodial mucus glands also occur in litiopids (see Houbrick, 1987b: 12, figs. 7, 12) and in some Bittium species (Marcus & Marcus, 1963:75, fig. 80; Houbrick, pers. obs). In litiopids and in some Bittium species, this gland produces a strong mucus thread, anchoring the animal to the substrate, as seen in Colina pinguis. It is therefore reasonable to infer that it has the same function in other Colina species.
The ovate, corneous, paucispiral operculum (figures 67, 68) is similar to the opercula of cerithiid species such as Bittium Gray, Cerithium Bruguiere, Ctijpeomorus Jousseaume, Rhinoclavis Swainson, and Pseudovertagus Vignal, differing only in having a subterminal nucleus.
The cephalic tentacles are very fat, wide, and stubby, each bearing a large eye at its peduncular base. The snout (figures 1, 2, sn) is short and has a bilobed tip. Both the snout and cephalic tentacles are probabK longer in living animals.
The dorsal mantle margin has a double fringe, but is smooth ventrally. The upper dorsal part of the double fringe is smooth, while the lower part bears long papillae. This fringed dorsal mantle edge occurs among all mem- bers of the Cerithiidae. but is absent in litiopids. The exhalant siphon protrudes slightly, and the dorsal mantle edge adjacent to the inhalant siphon is marked by a deep, left-central cleft, which has enlarged, protruded papillae and a darkK pigmented undersurface.
The mantle ca\ ity is deep and spacious. A ver\- broad bipectinate osphradium (figure 5), comprising tall pec- tens, tapers posteriorly and extends nearly the full length of the ctenidium. The ctenidium is as long as the mantle cavity, twice as broad as the osphradium, and comprises long, tall leaflets, narrow at their left leading edges and becoming long and shallow to the right. The hypobran- chial gland is thick and glandular and as broad as the ctenidium. The rectum is half as wide as the hvpobran- chial gland and is filled with many white, ovoid stacked fecal pellets. The male pallial gonoduct is open, ty pically cerithioid, and has many transverse glandular folds along its entire length. These probably comprise the prostate and possibly a spermatophore forming organ, respec-
Page 50
THE NAUTILUS, Vol. 104, No. 2
lively. No spermatophores were found, but as they are t>pical of teritliioideatis. the\ prohabK occur in this group as well. The fcmaie paliial o\ ickKts are unknown. .■\ltliough the nianllc cavity organs of Colina pingiiis are t\pically cerithioid, the ver\ broad bipectinate osphra- dium is unusual, especially in such a small snail; other- wise, it is typical of those seen in Cerithiuni species (Marcus & Marcu.s, 1964). In litiopids (Houbrick, 1987b: 13) and some Bittium species (Marcus & Marcus, 1963: 78-79, fig. 88, y) the osphradium is monopectinate, while in other Bittium species it is a simple ridge (Houbrick, pers. obs.). The morphology of the ctenidial filaments in Colina piiiguis is very similar to those seen in litiopid and Bittium species.
The buccal mass is moderately large, filling the short snout. There are two semilunar shaped prismatic jaws. A pair of thin, tube-like salivary glands coil tighti\ in front of the nerve ring, but extend through and originate behind it. The taenioglossate radula (figures 42-44 & 74-76) of Colina species is of moderate size, about one- seventh the shell length. The rachidian tooth is square, having a cutting edge with a large pointed central cusp flanked by two blunt denticles on each side. The basal plate of the rachidian tooth has a small median posterior e.xtension and a weak raised fold at each lateral edge. The lateral tooth is rhomboid-shaped, having a wide, posterior pillar-shaped extension on the basal plate and a moderate lateral extension. The marginal teeth are spatulate with curved serrated tips. The shape and den- tition of the rachidian tooth of the radula of Colina species (figures 44, 76) are unlike those of litiopids and man\ Bittium species, which have hourglass-shaped bas- al plates (see Houbrick, 1987b:12, figs. 13-14; 15, figs. 18-19; Marcus & Marcus, 1963:75, fig. 81): in Colina species, the rachidian is more squarish, as in many Cer- it Ilium species.
The stomach and anterior alimentary tract of Colina pinguis are l\pical of cerithiids and litiopids. Immedi- ately behind the nerve ring, the midesophagus is twisted and expands to form a large esophageal gland whose inner epithelium is thrown into many transverse ridges. E.sopliageal glands also occur in Cerithiuni. Clypcomo- rua and Bittium species (Houbrick, 1974, 1985, in press) and in litiopids (Houbrick, 1987b). The posterior esoph- agus is a narrow straight tube. The large stomach is lined interiorly with many small ridges and grooves torming complex sorting areas. A raised central pad divides the sorting area; a cuticular gastric shield and a short, but distinct, style sac are present. Although a crystalline style was not observed in preserved specimens, short style sacs and styles occur in Cerithiuni and Clypcomorus species (Houbrick, 1985). Examination of fecal pellet contents, ;ind the morphology of the radula and alimentary system, ' ariiciilariy the sorting surface, gastric shield, and style ' "I the stomach, suggest that members of this genus ' .i!ii:i. 'uhagous herbivores. I 'i' nt r\oii> system is epiathroid. The right cerebral aini I '. .r,;il ganglia are closely joined, but there are very long M-. l.io-pcdil connectives. The pedal ganglia lie
deep in the foot, each having a statocyst on its inner side. The supraesophageal connective is very long. The gan- glia of the nervous system are thus typically cerithioid in layout, but the long cerebro-pedal connectives are notable.
The kidney extends posteriorly, about one-half of a whorl in length. Only one lobe was discerned, and there is a large kidney opening into the posterior mantle cavity.
Ecology: Very little has been recorded about the hab- itats and life histories of Colina species. In the original description of the genus, H. & A. Adams (1854:286) remarked that "The species known are inhabitants of deep water, living in coarse sand. ..." This statement appears to be erroneous, as museum records of all species examined cite intertidal to shallow subtidal habitats. The few data available from collection records indicate that Colina species are closely associated with weedy or algal substrates.
Colina species appear to use a thread of mucus pro- duced by the large metapodial mucus gland to anchor themselves to their algal substrate in much the same way that litiopids (Houbrick 19S7b:ll) and some Bittium species do (Houbrick, pers. obs). This phenomenon has been observed by Kilburn and Rippey (1982:55). who recorded that Colina pinguis ". . . anchors itseli with elastic threads."
Conclusions: Colina is not a speciose genus and does not have an extensive fossil record, only one Pleistocene record being recorded (Abrard, 1942:61). Although some external anatomical characters such as the epipodial skirt fringed with papillae, a large papillate operculiferous lobe, and deep propodial and mesopodial mucus glands are similar to those seen in species of Alaba H. & A. Adams 1853, and Litiopa Rang, 1829, family Litiopidae (see Houbrick, 1987b), the combination of shell and other anatomical features are more like those observed in members of the Cerithiidae, especialK' in Bittium species. Iri addition, some Bittium species have a mesopodial mucus gland. These include a shell with a distinct si- phonal canal and a protoconch similar to those Bittium, Cerithiuni. and Clypcomorus species with direct de\el- opment. The attached surface of the operculum of Col- ina (Figure 67) does not have the spiral ridge seen in litiopid species (see Houbrick, 1987b:10, fig. 1), but is more like those of the cerithiids (see Houbrick, 1974; 1985). Other anatomical characters of Colina. absent in litiopids, include the fringed papillate dorsal mantle edge, a long broad columellar mu.scle, short, fat cephalic ten- tacles (which may be artifactual), a squarish rachidian tooth, and coiled sali\ary glands (straight tubes in litiop- ids). With the exception of the long, broad columellar muscle and short, fat, cephalic tentacles, these characters are present in Bittium. Cerithiuni. and Clypcomorus s|)ecies.
.•\s the temale paliial oN-iduct anatomy of Colina is unknown, comparison of paliial oviducts of cerithiid gen- era thought to be closely related to it is not possible. Ne\crtlieless, the known shell, radular. and anatomical
R. S. Houbrick, 1990
Page 51
cliaracters of Colina species clearly suggest an assign- ment of this genus to the Cerithiidae, subfamiK Ceri- thiinae Ferussac, 1819, close to the general Bittium Gra%', 1847, Cerithium Bruguiere, 1789, and Clypeomorus Jousseaume, 1888. As more knowledge of the smaller- sized and obscure cerithiid genera is accumulaletl, these data, along with those from Colina. can be utilized in a more complete cerithioidean ph\logenetic analysis (see Houbrick, 1988). Only then will the generic relationships become clearer and have a more substantial basis.
ACKNOWLEDGEMENTS
For loans of types and specimens I thank the curators and collection managers of the follow ing museums: Dr. Riidiger Bieler (DMNH), Dr. Philippe Bouchet (MNHNP), Dr. George Davis (ANSP), Mr, Ian Loch (AMS), Dr. James McLean (LACM), Dr. Richard Petit (Manchester Museum), Ms. Alison Trevv (NMW), Ms. Kathie Way (BMNH), Dr. Fred Wells (WAM). I thank Mr. Victor Krantz, Smithsonian Photographic Services. The Smithsonian Scanning Electron Microscope Labo- ratory assisted w ith preparations of micrographs. I am grateful to Ms. Shelley Greenhouse for checking the orig- inal draft of this manuscript for errors.
LITERATURE CITED
Abrard, R. 1942. Mojlusques Pleistocenes de la Cote Fran(,'aise des Somalis recueillis par E. .Hubert de la Rue. Archives du Museum National d'Histoire Naturelle, 6me serie 18: 105 p., 8 pis.
Adams, A. 1853. Description of new species of shells, in the collection of Hugh Cuming, Esq. Proceedings of the Zoo- logical Society of London, Part 21 173- 176, pi. 20
Adams, A. 1854. A monograph of Cerithidca. a genus of Mollusca, with descriptions of several new species, from the collection of Hugh C^uming, Esq.: to which are adiled two new species of Colina, and one of Donax. Proceedings of the Zoological Society of London, Part 22:83-87,
Adams, A. 1853-1855. The genera of Recent Mollu,sca 1(1- 8):l-256(1853);l(9-15):2.57-484(1854);2(19-24):93-284 (1855). London.
.^dams, H. 1866, Descriptions of a new genus and a new species of niollusks. Proceedings of the Zoological Society of London, 1866, p, 150-151.
Adams, H. 1867, Descriptions of new species of shells. Pro- ceedings of the Zoological Societ\ of London. 1867. p. 307-309, pi. 19, fig. 20.
Adams, H. and A. Adams. 1853-1858. The genera of Recent Mollusca; arranged according to their organization 3 \ols London, 389 p., 138 pis.
Bayle, E. 1880. Liste rectificative de quelques nonis de genres et d'especes. Journal de Conch\liologie 28(3):240-251,
Bellardi, L. 1850. Raisonne des fossiles nunnnuliti(|ues du Conte de Nice. Memoirs de la Societe Geologique de France (serie 2) 4:205-300, pis.
Bosch, D. and E. Bosch. 1982. Seashells of Oman. Longmans, New York, 206 p., illustrated.
Bruguiere, J. G. 1789, 1792. Encyclopedic methodique: his- toire naturelle des vers. l(l):l-344 (1789); l(l):345-758 (1792).
('oinad, T. .\, I S6() Ocsrriptinusol new spccii-s of Cretaceous and Eocene fossils of Mi.ssissippi and Alaliarna, Journal of the .\cadem\ of Natural Sciences, Philadeiplii.i (series 2) 4:275-298, pis. 46-47,
Cossmann, M. 1889. Catalogue illu.slre des eociuilles iossiles de I'Eocene des environs de Paris Societe Ro\ale Mala- cologique de Belgique, Part 4:380 p , 12 pis
Cossmann, M. 1906. Essais de paleoconchologie comparee, X'olume 7, Paris, 261 p., 14 pis.
Delrance, \! J L 1816-18.30. Dietionnaire des sciences iia- turelles. . . . Paris. 60 vols
Ferrussac, J, B. L. d'A de. 1819, Histoire naturelle general et particulire des mollusques terrestres et flu\iatiles. \ol, 1 Paris. (1-28): 128 p., 162 pis.
Fischer, P, 1880-1887. Manuel de conchyliologie el de pa- leontologie conein liologique ou histoire naturelle des mollusques rivants et fossiles. Paris, .\.\iv + 1369 p., 23 pis. (F"ascicule 6, p, 513-608, 1883; fascicule 7. p, 609- 688, 1884),
Goldfuss, G, .\.. von. 1820, Handhuch der Zoologie 2, N'urn- berg
Ciray, J. E. 1847. The classification of the British Mollusca h\ N. E. Leach, M D .Annals and Magazine of Natural His- tor\ 20:267-273,
Hinds, R, B, 1844, Zoology of the voyage of HM.S. Sulphur, under the command of Capt. Sir Edw. Belcher, during the vears 1836-42, X'olume 2. Mollusca. London, 72 p.. 21 pls.^
Houbrick, R. S, 1973. Studies on the reproductiw l)iology of the genus Cerithium (Gastropoda: Prosobranchia) in the western Atlantic, Bulletin of Marine Science 23:875-904,
Houbrick, R, S, 1974. The genus Cerithium in the western Atlantic. Johnsonia 5(50):33-S4, pis. 13-48.
Houbrick, R. S. 1984. Revision of higher ta.\a in genus Cer- ithidea (Mesogastropoda: Potamididae) based on compar- ati\e morphology and biological data. .American Mala- cological Bulletin 2:1-20
Houbrick, R, S, 1985. Genus C7i/pcr;f?if;r(/.s Jousseaume i(!er- ithiidae: Prosobranchia). Smithsonian C'ontributions to Zo- ology, No, 403:iii + 131 p,, 62 figs,
Houbrick, R, S, 1987a. Description of a new giant Ataxoeer- ithium species from Australia with remarks on the system- atic placement of the genus (Prosobranchia: Cerithiopsi- dae). The Nautilis 101(4):155-161,
Houbrick, R, S, 1987b, Anatomy of Alalia and Litiopa (Pro- sobranchia: Litiopidae), The Nautilis 101(1):9-18,
Houbrick, R, S, 1988, Cerithioidean ph\logen\, Malacolog- ical Review, Supplement 4:88-128,
Houbrick, R S. 1989, C'ampanile resisited: implications for cerithioidean phvlogen\ ,\merican Malacological Bulletin 7(l):l-6.
Houbrick, R. S. (in press). Monograph of the genus Cerithium Bruguiere in the Indo-Pacific (Cerithiidae; Prosobranchia). Smithsonian (Contributions to Zoologv.
international C'ode ol Zoological Nomenclature [IGZN], 1985, Third edition. Ride, WD, L, C W Sabrosk\ . G Bernardi, and R \' Mel\ille(eds.). International Trust for Zoological Nomenclature, London xx -i- 338 p.
Jablonski, D. and R. A. Lutz. 1980. Molluscan larval shell morphology: ecological and paleonlological applications. In: Rhoads, D. C. and R. .\. Lutz (eds. ). Skeletal growth of aquatic organisms. Plenum, New York, p. 323-377.
Jousseaume, F. 1888. Description des mollusques recueilles par le Dr. Faurot dans la Mer Rouge et la (;olfe d'.Xden Memoirs de la Societe Zoologique de F'rance 1(2): 12-223
Page 52
THE NAUTILUS, Vol. 104, No. 2
Jousseaume, F. 1930. CA-rilhiidae de la Mcr Rouge. Journal
de C^onchyliologie 7-1:270-296 Kilburn, R. and E. R. Rippey 1982 Sea shells of soutliein
Africa. Hong Kong, 249 p , 46 pis. Marcus E. and E. Marcus. 1963. Mesogastropodeii von der
Kuste Sao Paulos. .Ahhandiungen der Matiieniatiscli-Na-
turwissenshaftliclien Klasse Jalirgang 1963, 1:1-105. Marcus, E. and E. Marcus. 1964. On Cerithium atratum
(Born, 177S)(Gastropoda: Pro.sobrancliia) Bulletin ot Ma- rine Science of the (iult and (;aribl)ean 14(3):494-510.
figs. 1-12. Marshall, B. A. 1980. The systematic positioti of Trifuris
Deshayes (Mollusca: Clastropoda), New Zealand Journal of
Zoology 7:85-88. Melvill, J. C. and R. Standen. 1898. The marine Mollusca ot
Madras and the immediate neighbourhooil. Journal ot
Conchology 9:30-48. pi. 1, Nuttall, T. 1832. A manual of the Ornithologv of the Ignited
States and Canada, the land liirils. 1st ed C'ainhridge. viii
+ 683 p. Quoy, J. C. R and J V. Gaimard. 1833, 1834. Voyage de
decouverts de 1 Astrolabe execute par ordre du Roi pendent
les annees 1826-1827-1828-1829 sous le commandement
de M. J. d'L'rville. Zoologie 3(l):l-366 (1834) + Atlas
(1833), 93 pis. Rang, P. S. 1829. Notice sur le Litiope. Liliopa, genre nou-
veau de MoUusques gasteropdes, .Annales des Sciences Na-
turelles 16(3):303-307. Robertson, R. 1974. Marine prosobranch gastropods: larval
studies and systematics. Thalassiajugoslavica 10(1-2):213-
238. Sars, G. O. 1878. 15idrag til Kundskaben om Norges Arktiske
Fauna. 1. Vlollusca regionis .^rticae Norvegiae (^ristiania,
466 p., 18 pis. Schumacher, C. A. 1817. Essai dune nouveau septeme des
habitations des vers testaces. Copenhagen, 287 p., 22 pis.
Smith, E A. 1884. Mollusca (p, 34-116. pis 4-7) in Report on the zoological collections made in the Indo-Pacilic Ocean during the voyage of H.M S ".Alert" 1881-82 London, 684 p., 54 pis.
Smvthe, K., ed. 1982. Sea shells ol the .\rabian Gulf London, ' 123 p., 20 pis.
.Sowerby, G. B. 1855, 1866. Monograph of the genus Ceri- thitnn. .Adanson. /;i: Thesaurus Conchvliorum, or Mono- graphs of Genera ot Shells. London 2(16):847-899, pis. 176-186. [pi. 12, published as a supplement in 1866].
Sowerby, G. B. 1865-1866. Monograph of the Genus Ceri- thium, .\danson. In: L. A Reeve, Conchologia Iconica: or illustrations of molluscous animals. London, 15 [atlas], 20 pis. + index.
Tate, R. 1894. L'nrecorded genera of the older Tertiar\ fauna of Australia, including diagnosis of some new genera and species. Journal of the Ro\al Societv of New South Wales 27:1(57-198, pis. 10-13.
Thiele, J 1929 Handbuch der systematischen Weichtier- kunde. liand 1, Teil 1, Jena, 376 p., 470 figs.
Tryon, G. W. 1883. Structural and systematic conchology: an introduction to the stud\' of Mollusca, Vol 2. Philadelphia, 430 p., 22 pis.
Tryon, G. W., Jr. 1887. Orithiidae. in Manual of conchology; structural and systematic with illustrations of the species, first series. Philadelphia, 9:112-228 p., 19-39 pis,
\'errill, A. E. 1882. C^atalogue of marine Mollusca added to the fauna of New England during the past ten years. Transactions of the C^onnecticut Academv 5:447-.587, pis. 17-19, 57-58.
Wenz, \V. 1928-1944. Gastropoda. Teil 1: Allgemeiner Teil und Prosobranchia. In: O. H. Schindewolf (ed. ). Handbuch der Paliizoologie. Berlin 6: \i -I- 1,639 p. 4,211 figs.
THE NAUTILUS 104(2):53-56, 1990
Page 53
Two Unusual Gastropods From Late Pliocene Lakes in Northeast Nebraska
Harold C. Pierce
Research Associate
University of Nebraska State Museum
Lincoln, NE 68688, USA
ABSTRACT
Lyninaca {Acella) haldanani Binney 1867 and Acroloxus colo- radoensis (Henderson 1930), rare as living species and unusual as fossils, are found in a late Pliocene lacustrine assemblage in northeast Nebraska in association with two extinct taxa, Ont- alodiscus paltersoni (F. C. Baker, 1938) and Deroceras aenig- ma, Leonard 19,50. Climatic interpretation, based on the re- maining mollu,scan fauna, suggest the late Pliocene climate, immediately preceeding the first glacial advance, approximat- ed that of the present.
curring during pluvial intervals on the High Plains, sug- gesting additional investigations involving other known fossiliferous deposits in the immediate area. A second locality, some 6.5 kilometers (4 s.m.) north of the Clark Mills Locality, the Niekles Gravel Pit, UNSM KX 109 (Figure 1), was sampled, largely on the report of a late Blancan microvertebrate fauna, an associated ash, and an overlying till (Voorhies, pers. comm.). Samples pro- cessed from this locality produced a second molluskan fauna, w hich matched verv well the Clark Mills fauna.
During the 1988 field season. Dr. K. G. Goodwui, De- partment of Geology, Llniversity of Nebraska-Lincoln, discovered fossiliferous lacustrine sediments in Knox County, Nebraska associated with a volcanic ash and underlying a glacial till. Dr. M. R. Voorhies, Curator of Vertebrate Paleontology, University of Nebraska State Museum, quarried and processed approximately one metric ton of sediment from the locality now known as the Clark Mills Local Fauna, UNSM KX 143 (figure 1). Mammals recovered indicated a late Blancan age (2.0- 2.5 MA) for the fauna, and paleomagnetic analyses in- dicate that the sediments were deposited in a reversed magnetic field (Matuyama Reversed Epoch) (Voorhies & Goodwin, 1989). On this basis, the ash is identified as Pearlette Type B, fission-track dated at 1.97 MA (Boells- dorf, 1973:39), hence, of late Pliocene age.
In addition to the mammals, an unusually diverse fish fauna was recovered, to include such northern species as walleye {Stizostedion vitrettm), northern pike (Esox, cf. £. luciiis), muskellunge (Esox. cf. £. masqitinongij), and an undetermined trout (Salmonidae, Gen. et sp. indet.) (Voorhies, pers. comm). The mollusks recovered while sorting for vertebrates were given to me for study. Fur- ther collection of material from this locality in 1989, collected at controlled stratigraphic intervals, was pro- cessed specifically for mollusks and ostracods. The larger gastropods were somewhat crushed, but all taxa were identifiable with confidence. A generally typical cool water fauna was identified, suggesting that cool, pluvial conditions existed at time of deposition (table 1) This fauna differed from the typical Pleistocene faunas oc-
•SD
BROWN
|
"^ |
v.. |
J |
r-^ ^KX 109 |
|
• |
|||
|
.'-KX 14 3 |
|||
|
K |
N |
0 |
X |
Figure 1 Locality map of C:lark Nhlls Locality (KX 1-43), NIckles Pit Locality (KX 109), l)oth Knox County, Nebraska, and Sand Draw Locality (SU), Brown Counts, Nebraska.
Page 54
THE NAUTILUS, Vol. 104, No. 2
Table 1. Comparison of faunas of the Clark Mills Locality (KX 143), Nickles Pit Locality (KX 109) and Sand Draw Locality 6. Frequency data: VR = 1; R = 2-5; F = 6-1.5; C = 16-50; A = 51-200; VA = >200. X = Reported b\ Taylor, 1960, from Sand Draw, but not his complete list * = Extinct taxa, or taxa not known with certainty to still exist locally
I'auiuil list
KX 113
Lower
Up pel
KX 109
Sand Draw
\'alvatidae
Valvata lewisi Curier 1868 v. Iricarinata (Say 1817)
Planorhidae Cijraidus parvus (Say 1817) I'ronu'netiis cxacuous (Say 1821) P. nmhilicatellus (Cockerell 1887) Omalodiscus pattersoni (F. (;. Baker 1938)* Planorlnda annigera (Say 1818) Planorbella trivolvis (Say 1817) //. anceps (Menke 1830)
L\ iMiiaeidae Lyninaea hiirnilis Say 1822 L. palustris (Muller 1774) /.. hnlitnoUlcs Lea 1841 (?) /. Imlclciiiuni Binney 1867*
Pii\si(iae Phijsclla gyrina Say 1821 P. sp. ianalina'i') Phijsa jcnncs.si skinncri (Taylor 1954)*
Ancylidac
Acroloxus coloradocnsis (Hend. 1930)* Fcrrissia mci'kiaiui (Stimpson 1863)*
Carscliiidae
(■/irychiiau cxigiiiiiu (Say 1822) Liinacidac
Dcrocrras acnignia Leonard 1950* Cen. & sp. indet.
Succineidae cf. Sticcinea Oxyloma sp.
Pupillidae Caslrocopta pcniodun (Say 1821) G. armifera (Say 1821) ' ablrreviata G. contracta (Say 1822) C. holzingeri (Sterki 1889) Vertigo nvata Sa\ 1822 V. mdium ((Jould 1840) Pupilla museorum (Liim. 1758)* Pnpoidi's allrilabris (C. B. Adams 1841)
\ allnniidae Vallonia pidrhclla (Muller 1774) \'. parvula Sterki 1893
/nnitidae
Haiiiiiia mmusctda (Binney 1840)
1- in'odiiiilidae
ililiroihsciis .•iinglpyamis (Pilsliry 1890)
Gastropods Aquatic
F C
A C
R C
R
R VR
Terrestrial
R R
VR
R F F
VA C
F R
VR
A A C
VA
C
R
C F
R
C R R
F R
A R
A
A
VA
C
X
X
A C
F X F
X X
|
R |
F |
|
R |
|
|
F |
X |
|
F |
|
|
C |
F |
|
R |
R |
|
\'R |
|
|
R |
|
|
R |
F |
|
\H |
R |
|
\R |
|
|
F |
|
|
\R |
X |
|
R |
|
|
F |
R |
|
H |
X |
H. G. Pierce, 1990
Page 55
Table I . ( 'iintiriurd
FauMul list
K.\ 143
l.uuer
Ippt-r
K\ 109 Sand Drav
Bivalves
Uninnidae Gen. & sp. indet,
Spliaeriidae Pisidium. cf. P. ualkcri Sterki P.. cf. P. ventrkusuni Prime 1 Sphaeritim partumeium (Say S., cf. S. simile (Say 1816)
Ostracodes
Large candnnid
Plant Cliara sp,, oogonia Rhus sp., sumac nutlets C'cltis sp , liackherr\ nutlets
1895 851 1822)
A C F
A C
C VA
F
F
VR
VR
C C
A
F F
and included a good sampling of the terrestrial gastro- pods that were poorly represented in the Clark Mills fauna. Table 1 compares these two faunas and a fauna collected at Taylor's (1960:34) Sand Draw Locality 6, Brown County Nebraska, which is supplemented by oth- er taxa reported by Taylor from Sand Draw Localities.
Two unusual gastropod species make the Knox County faunas remarkable. The fauna of the oldest lacustrine section at the Clark Mills Locality, beneath the ash, in- cluded three incomplete (2.5-4 whorls), but readiK iden- tifiable Lymnaea (Acella) haldemani Binney, 1867 (fig- ure 2) and eleven Acroloxus coloradoensis (Henderson, 1930) (figures 3, 4). Although no L. haldemani were recovered at the Nickles Pit Locality, that fauna did include A. coloradoensis. Two extinct species were also found, Omalodiscus pattersoni (F. C. Baker 1938), re- covered only at the Clark Mills locality, and Deroceras aenignia Leonard 1950, found at both localities. For L. haldemani, this represents a considerable extension in range, both geographic and stratigraphic. Records of liv- ing specimens are restricted to the Great Lakes drainages and the Hudson River system (F. C. Baker, 1928:270; LaRocque, 1968:456). Fossil occurrences have been un- common, restricted to latest Pleistocene (Wisconsinan) of Ohio (LaRocque, 1968:456), and from two medial Pleistocene (Illinoian) localities in Illinois (Leonard et al.. 1971:6). Acroloxus coloradoensis is even less common, currently known to exist only in a very few lakes of river systems tributary to the Arctic Ocean or Hudson Ba\ (Clarke, 1973:263: Mozley, 1926:56), and in a remote mountain lake in Colorado (Walker, 1925:1). Fossil oc- currences are only two, the Sand Draw Local Fauna, Brown County, Nebraska, and the Dixon Local Fauna, Kingman County, Kansas (Taylor, 1960:32-40), both of late Pliocene age (late Blancan, 2.2-3.0 MA).
Comparison of the faunas of these two Knox County localities with nearb\' modern faunas is most instructi\e.
With the exception of the four aforementioned species, over 90% of the mollusks listed in table 1 are currently found living within an approximately 160 kilometers (100 s.m.) radius in northeastern Nebraska, southeastern South Dakota, southwestern Minnesota or northwestern Iowa. The two trees and the fish are also found locally, or within a similar radius. It can, therefore, be inferred that the climate of northeast Nebraska during the late Pliocene, immediately preceding the first glacial ad- vance, was quite similar to, but slightly cooler than, that of today. The presence of lakes in an area presently lacking lakes suggests either greater annual precipitation, or lessened evaporation due to cooler summer maximum temperatures.
Figures 2-4 Unusual Gastropods from the late Pliocene of northeastern Nebraska. 2 Lymnaea (Acella) haldemani. K\- 14:5. aperture hroken back about '/2 whorl; 3-4. Acroloxus colo- radoensis. broken specimens, 3, KX-143, 4. KX-109, All lOx,
Page 56
THE NAUTILUS, Vol. 104, No. 2
LITERATURE CITED
Baker, F. C. 1928. The frt'sli water Mnllusca of Wi.scoiisiii, Part 1. CJa.strnpoda Wiseonsin Geological and Natural His- tory Sarve\ Bulletin 70, Part 1. 507 p
Baker, F. C. 1938. New land and freshwater Mollusca from the upper Pliocene of Kansas and a new species of Gy- raulus from early Pleistocene strata. Nautilus .51:126-131.
Biiinev, VV. G. 1867. Notes surquelquesespecesdemollusques Quviatiles de I'Amerique du Nord. Journal Conchliologie 15:-427-132.
Boellsdorf, J. 1930. Fission-track ages of Pleistocene volcanic ash deposits in the Gentral Plains, U.S.A. Isocliron/West 8.39-42.
Clarke, A. H 1973. The freshwater mollusks of the C'anadian interior basin. Vlalacologia 13(1-2) :l-509
Henderson, J. 1930. Ancyhis coloradoensis, new name for A. hendersuni Walker, 1925, not 1908. Nautilus 44:31.
LaRocque, A. 1968. Pleistocene Mollusca of Ohio. Ohio Di- vision of Geological Surve\ Bulletin 62. Part 3 pp. 357- 553.
Leonard, .\. B. 1950. .■^ Varrnouthian molluscan fauna in the Midcontinent region of the L'nited States. University of Kansas Paleontological Contributions, Article 3, 48 p.
LeonartI, \ B , J C. F'r\e, and \V. H. Johnson 1971 lllinoian and Kansas molluscan faunas of Illinois. Illinois State Geo- logical Survey (^iircular 461, 24 p.
Mozley, A. 1926. Preliminary list of the Mollusca of Jasper Park, Alberta. Nautilus 40:53-56.
Ta\lor. D. W. 1960. Late Cenozoic molluscan faunas of the High Plains. U.S. Geological Survev Professional Paper 337, 94 p., 4 pi
N'oorhies, M. R and R. G. Goodwin 1989 Plio-Pleistocene glacial deposits of northeastern Nebraska: new exposures and interpretations. Nebraska Geological Societ) . no pagi- nation.
Walker, B. 1925. New species of North American .\nclyidae and Lancidae. University of Michigan Museum of Zoology Occasional Paper 164, 13 p
THE NAUTILUS 104(2):57-71, 1990
Page 57
A New Molluscan Faunule from the Caribbean Coast of Panama
Edward J. Petuch
Department of Geology Florida Atlantic University Boca Raton, FL 33431, USA
ABSTRACT
The Carribbean coast of Panama, particularK the area aroumi the San Bias Archipelago, has been iound to represent part ot a new subregion of the Caribbean Molluscan Pro\ince, antl harbors an endemic gastropod fauna. This new faunal di\ision, referred to here as the Blasian Subregion (for the San Bias Archipelago), characteristically contains a large number of Pan- amic-Caribbean cognate species pairs, and has a distinctive Panamic appearance. Being predominantK a coralline area in an otherwise muddy region of the Caribbean, the Blasian Subre- gion also contains numerous taxa that are closeK related to coral reef-dwelling species from the Bahamas and Florida. The Blasian Subregion ends abrupth at the Golfo de Uraba, on the Panama-Colombia l)order and, based on peripheral data, ma\ extend northward to the Costa Rica-Nicaragua border. Si.xteen new Blasian species are described, including TurrilcUa mart- anopsis n.sp., Chicoreus hilli n.sp., Dcrmomurcx (Trialatella) cuna n.sp., Murexiella edivardpauli n.sp., Latirus cuna n.sp., Mitra {Nebularia) leonardi n.sp., Prunum leonardhilh n.sp., Valuta lacertina n.sp., Fahihjria crnesti n.sp., Contis brun- ncofilaris n.sp., Conus ernesti n sp., Conus hilli n.sp , Conus porlobeloensis n.sp.. Conns rosemanjae n.sp,, Fusiturricula sundcrlandi n.sp., and Kncfcistia hilli n.sp., and three new Blasian subspecies are described, including Mitrcx ruhidus pan- amicwi n.subsp., Oliva (Strephona) relindaris ernesti n subsp,. and Conus granarius panamicus n.subsp.
Key ivords: Caribbean; Panama; gastropods, San Bias Archi- pelago.
INTRODUCTION
The southern Caribbean region contains one of the least studied molluscan faunas in the Recent western Atlantic Although originalK thought to house a typical Caribbean tropical molluscan fauna (Valentine, 1973:356), the coastlines of eastern Central America and northern South America are now known to harbor geographically dis- crete faunules, each differing from one another in species composition (Petuch, 19SS). Two of these faunules, one along northern Honduras and eastern Nicaragua, and the other along northern Colombia and the Gulf of Ven- ezuela, were found to contain numerous living archaic genera and species complexes that pre\iousl\ were
thought to have been extinct since the late Pliocene (Petuch, 1980, 1981, 1982). These geographically sharp- ly-defined pockets, each with its own characteristic mol- luscan assemblage, demonstrate that the southern Carib- bean is not a faimistically homogeneous region but is, instead, a biogeographical mosaic of small, distinctive faunules.
While the gastropod faunas of coastal Honduras and Nicaragua, and northern Colombia and the Gulf of Ven- ezuela are now better known (Petuch, 1987, 1988), the intervening Caribbean coasts of Costa Rica and Panama have been, to date, poorly studied. Only a single large detailed work has ever been published on the molluscan systematics of this area (Olsson & McGinty , 1958). That paper, however, concentrated on the micromollusca and small macromollusca that were collected in beach drift near Bocas del Toro and Colon, Panama. Nevertheless, the authors described a number of unusual new species (some of which are listed later in this paper) and dem- onstrated that the Panama coast did not ha\e a typical West Indian-type Caribbean fauna. Houbrick (1968) fur- ther showed that several of Olsson and McGinty's new- Panama species were also present at Portete, Costa Rica. These range extensions indicate that the (Caribbean coasts of Panama and Costa Rica harbor a fourth Central .Amer- ican-northern South American faunal subregion. \ year later, Radwin (1969) published a species list of macro- mollusks that had been collected from dredged spoil piles near Cxilon. By incorporating the taxa of Olsson and McGinty, this smaller work became the first, and only, compendium of the molluscan faima of this fourth faunal subregion.
L'nlike the Honduran and Colombian mainlands, w hich have large areas of mudcK coastline [i.e.. the Gull of Uraba), the Caribbean coasts of Panama and Costa Rica contain large areas of coral reefs and coralline algal rub- ble bottoms. Typical of these carbonate areas are the reef platform and coral cays of the San Bias .Archipelago and the massive coralline algal reefs and ridges along the Portobelo coast and at Moro Tupo (Vermeij, 1978:88- 89). While working with local fishermen who trawl off- shore of these carbonate areas, several Panamanian mala- cologists, in particular Mr. James Ernest of Balboa, have
Page 58
THE NAUTILUS, Vol. 104, No. 2
recently collected numerous and important new species of macrogastropods. Since the ranges of the niicrogas- tropods of the Caribbean are still ver\ poorly know n, the biogeographical implications of Olsson and McGinty's micromolhisks, as indicators of a new faunal subregion, are too tenuous. On the other hand, the ranges of the Caribbean macrogastropods, particularly those of the eighteen eutropical index families (Petuch, 1988:6-7), are much better known. In this case, the macrogastropods collected by Mr. Ernest are excellent biogeographical indicators, especially since the ranges of their congeners in Honduras, Nicaragua, Colombia, and Venezuela have recently been established (Petuch, 1987, 1988).
The new taxa described in this paper help to demar- cate yet another biogeographical subregion of the Ca- ribbean Molluscan Province. This new subdivision is spatially bounded by the Honduran and Colombian- Ven- ezuelan Subregions (Petuch, 1988; figure 42) and includes the coasts of C^osta Rica and Panama. Since the San Bias Archipelago of Panama is the ecological and faunistic archetype, I here refer to this new biogeographical entity as the "Blasian Subregion". Unlike the Honduran and Colombian- Venezuelan Subregions, which contain nu- merous Pliocene Caribbean relictual taxa, the Blasian Subregion characteristically contains numerous Panam- ic-Caribbean cognate species pairs (scnsi/ Radwin, 1969). Of the nineteen new Blasian taxa described here, seven represent previously-unknown cognate pairs. The other twelve taxa include endemic Blasian members of Carib- bean species complexes. Nine gastropod families are rep- resented by the new species, and all of these higher taxa can be used for provincial subdivisional analysis (Petuch, 1988:5-8). Future collecting along the Panama-Costa Rica mainland may uncover sufficient faunistic data to support the elevation of the Blasian Subregion to sub- provincial status. At present, not enough information exists concerning the total molluscan fauna and, because of this lack, I prefer to refer to the area as a "subregion".
THE BLASIAN GASTROPOD FAUNA
As pointed out by Radwin (1969), the Blasian gastropod fauna bears a striking resemblance to the Panamic fauna of western Central and South America, and in particular, the Bay of Panama. For example, unlike the faunas of the adjoining Honduran and Colombian regions, the Bla- sian area contains a species of the turrid genus Knefaslia Dall, 1919 (described here), which is normally considered a classic Panamic group. Of particular interest in the Blasian area is the presence of the bizarre vermetid genus Stephopoma Morch, 1860 (Olsson & McGinty, 1958; Houbrick, 1968; Radwin, 1969). Like Knefastia. this characteristic Panamic gastropod is found in the (Carib- bean only within the Blasian subregion. The small, en- crusting vermetid, Stephopoma myrakeenac OLsson and McGinty, 1958, lives embedded within the coralline algal ridges along Colon and the San Bias Archipelago, and at Portete, Costa Rica, and is characteristic of the unitiue Blasian lithothamnion community.
The new Blasian members of gastropod cognate pairs are of particular importance in that they underscore the faunal ties to the Panamic-Eastern Pacific areas. Some newly discovered examples of Caribbean-Panamic cog- nates, based on new taxa proposed in the systematic section of this paper, include: Turritella marianopsis n.sp. and T. mariana Dall, 1908; Dermutnurex (Triala- tella) cuna n.sp. and D. (Trialatclla) cunniiighamae (Berry, 1964); Murexiclla edwardpaiiH n.sp. and M. keenae Vokes, 1970; Latirus cuna n.sp. and L. centri- fugus (Dall, 1915); Mitra (Nebitlaria) leonardi n.sp. and M. (Nebularia) sphoni Shask% and Campbell, 1964; Pntnum Iconardhilli n.sp. and P. curium (Sowerby, 1833); and Knefastia hilli and K. olivacea (Sowerby, 1833).
The Atrato Seaway, the last connection between the Pacific and Atlantic Oceans, closed at the end of the Pliocene (Whitmore & Stewart, 1965; Woodring, 1966; Petuch, 1988), and had its eastern opening along what is now the San Bias Archipelago and the Golfo de Uraba. This area, which was the last to be exposed to the Pacific molluscan fauna, would be expected to have the most Panamic-appearing molluscan assemblages in the Carib- bean. The recent discovery of whole suites of new cog- nate gastropods living along the Blasian area supports this hypothesis. The enclave of Panamic mollusks in the Caribbean, however, is geographically small, ranging from near San Juan del Norte, Nicaragua (near the Nic- aragua-Costa Rica border) in the west to the Golfo de Uraba in the east. The broad Honduras-Nicaragua con- tinental shelf, which contains the Honduran Subregion, narrows and ends at San Juan del Norte. At that point, the muddy environment of the Nicaraguan coast shifts to the cleaner carbonate environments of Costa Rica and Panama. A similar situation takes place at the western edge of the Golfo de Uraba, indicating that substrate type is the major limiting factor in the configuration and distribution of the southern Caribbean molluscan subre- gions. The substrate and bathymetric preferences of some of the new taxa are discussed under the individual de- scriptions in the systematic section. The entire Blasian Subregion, with its attendant faunule appears to occupy a stretch of coastline of only slightly over 800 km.
The following is a listing of some of the macrogastro- pods that are presentK known to be confined to the boundaries of the Blasian Subregion. Most of these belong to ke\' tropical biogeographical index families (as out- lined by Petuch, 1988). Several smaller macrogastropods that were described by Olsson and McGinty (1958) are also listed.
Turbinidae-Liotiinae
Arenc Intleri Olsson and McGinty, 1958 Turritellidae
Turritella marianopsis Petuch, n.sp. Vermetidae
Uteplidpoma myrakeenac Olsson and McGinty, 1958 CCerithiidae
Ceritliium carihhaeum M. Smith, 1946
E. J. Petuch, 1990
Page 59
Muricidae
*Chicoreus emihjae Petucli, 1987
Chicoretts hilli Petuch, n.sp,
Dermomurex ciina Petuch, n.sp.
Mitrexiella edwardpauli Petuch, n.sp.
Miirex rubidun panamicus Petuch, n.sp. Fasciolariidae
Latirits cuna Petuch, n.sp. Cohimbelhdae
Nassarina diibia Olsson and McGint\, 1958 Olividae
Oliva reticularis crncsti Petuch, n.subsp.
Olivella chiriqiiicnsis Olsson, 1956
Olivella marmosa Olsson and McGinty, 1958 Margineilidae
Gibhcrula bocasensis Olsson and McGinty, 1958
Persicula iveberi Olsson and McGinty, 1958
Prunum IconardhiUi Petuch, n.sp. Mitridae
Mitra (Nebularia) Iconardi Petuch, n.sp. Volutidae
Falsihjria ernesti Petuch, n.sp.
Valuta lacertina Petuch, n.sp.
Vohita Hndae Petuch, 1987 Conidae
Conns brunncofilaris Petuch, n.sp.
Conus ernesti Petuch, n.sp.
Conns granarius panamicus Petuch, n.subsp.
Conns hiUi Petucli, n.sp.
Conns portobeloensis Petuch, n.sp.
Conns rosernaryae Petuch, n.sp. Turridae
Fnsitnrricula sunderlandi Petuch, n.sp.
Knefastia hilli Petuch, n.sp.
SYSTEMATIG SECTION
The type material of the following new species is de- posited in the collection of the Division of Mollusks, National Museum of Natural History, Smithsonian In- stitution, Washington, DC,, and bears USNM numbers:
Gastropoda Prosobranchia Gaenogastropoda Gerithiacea
* Note Due tu an error in my field notes, 1 iiicorreeti) gave the type locality of Chicoreus emilyae as "off Punta Patuca, Honduras" (Petuch, 1987:65). This erroneous type locality is here emended to "Bocas del Toro, Panama ', the locality of the paratype. The other paratypes that came from "off Roatau is,, Honduras ', appear to represent another, undescribed Chico- reus species, and not E. emilyae. Chicoreus emilyae has now been found to be a true Blasian endemic This is probably the "Chicoreus ftorifer" listed b> Radwin (1969:231).
Family Turritellidae
Genus Turritella Lamarck, 1799
Tnrritella marianopsis new species
(figures 1-3)
Material examined: Holotype — Length 58 mm, trawled by commercial fishermen from 65 m depth off Portobelo, Panama, USNM 860523; Paratypes 1-3— same locality and depth as holotype, lengths 52, 44 and 47 mm, USNM 860524.
Description: Shell tightly coiled, very elongated, classi- calK turritelliform; whorls with 2 large cords, with the anterior cord being better developed and projecting far- ther from shell than posterior cord; 2 large cords strongly beaded, giving shell rough appearance; 2 smaller, thin, beaded threadlike cords present between 2 large cords, and 1 thin beaded cord present between posterior cord and suture; shell color brownish-tan with numerous closely-packed, thin, darker brown longitudinal flam- mules; early whorls pale whitish-tan; beaded cords with alternating light tan and dark brown spots, giving shell speckled appearance; base of shell light tan with scattered tan flammules; aperture wide, slightly rectangular in shape.
Etymology: Named for the new species resemblance to the Panamic Turritella mariana Dall, 1908 (. . . "look- ing like mariana").
Discussion: Turritella marianopsis is morphologically closest to the Panamic T. mariana Dall, 1908, especially in shell shape, color pattern, and number of spiral cords, but differs primarily in being more coarsely sculptured, with larger beading and stronger, more elevated spiral cords. Otherwise, the two species are very similar and form an excellent example of a Panamic-Caribbean cog- nate pair. According to local collectors, T. marianopsis is an abundant species at depths of around 60 m, and apparently forms solid beds off the Portobelo coast.
Muricacea Muricidae Chicoreus Montfort, 1810
Chicoreus hilli new species (figures 4, 5)
Material examined: Holotype — Length 26 mm, traw led by commercial fishermen from 65 m depth off Portobelo. Panama, USNM 860525; Parat)pes 1, 2— lengths 24 and 26 mm, same locality and depth as holotype, Leonard Hill collection; Paratype 3 — length 24 mm, same locality and depth as holotype, USNM 860526.
Description: Shell small for genus, fusiform in shape, thin and delicate; 3 well de\eloped varices per whorl; each bod) varix ornamented with 4 spines — one large spine on shoulder, one small spine at midbody, and 2 small spines clumped together at bod\ whorl-siphonal canal junction; large spine on shoulder 4 times length oi smaller spines; small, scalelike spines sometimes present
Page 60
THE NAUTILUS, Vol. 104, No. 2
between larger spines on varix; varical spines open, cupped, ramose; inter\arital areas ornamented \\ ith one large, elongateil knob; bodv whorl sculptured with 12- 13 thin, raised spiral cords; one or more very fine sec- ondary threads present between cords; siphonal canal very elongated, narrow, ornamented with 3 large, flat- teneil spines per varix; spiral cords and threads on body « horl and siphonal canal minutely scaled; aperture pro- portionally large, ovate; shell color light brownish-tan, \\ ith varices and intervarical knobs being of darker chest- nut brown.
Etymology: Named for Mr. Leonard C. Hill of Miami, Florida, who recognized the species as new and who kiiulK donated the type material.
Di>icussion: Chicoreus hilli is closest to C mergtis Yokes, 1974 from Florida, the West Indian .Arc, and northern South America, but differs in being a smaller, thinner, more elongated shell with proportionally much larger spines. The varices of Chicoreus mergus are very thick and rounded, giving the shell a compact, squat appear- ance. The varices of Chicoreus hilli, on the other hand, are much thinner and sharper, giving the shell a more elongated, graceful appearance. The siphonal canal of C. hilli is also much narrower and proportionally much longer than that of C. mergus. The shoulder spine of C. hilli is also proportionally at least twice as long as the shoulder spine of C. mergus.
Chicoreus hilli is also similar to Chicoreus bullisi Yokes, 1974, from off Nicaragua, but differs in being a much smaller, much more delicate shell with smaller and less- developed varical spines. The varices of C. bullisi, like those of C. mergus, are also much thicker, wider, and more rounded than those of C hilli. The new species is the smallest known Chicoreus in the western Atlantic, and appears to be restricted to the coralline algal and carbonate rubble areas off Portobelo and the San Bias Archipelago.
Dermomurex Monterosato, 1890 Tridatella Berry, 1964
Dermomurex {Trialatella) cuna new species (figures 9, 10)
Material examined: Holotype — Length 14 mm, trawled by commercial hshermen from 65 m depth off Portobelo, Panama, USNM 860527; Paratype 1— length 13 mm, same locality and depth as holotype, Leonard Hill col- lection, Miami, Florida.
Description: Shell elongated, fusiform, thin and fragile; early whorls with 6 small thin varices per whorl; body whorl and penultimate whorl with 3 large, thin, winglike varices per whorl; bodv whorl ornamented with 6 low flattened cords with cord along shoulder being strongest and best developed; cords extend onto winglike varices, producing slightly scalloped edges; cords of intervarical areas ornamented with small, evenly-spaced nodules; si- phonal canal elongated, well developed, slightly re- curved; aperture proprotionally large, oval in shape; en- tire shell covered with thick, cream-white, pebbled intritacalx; surface of intritacalx of varices finely striate.
Etymology: Named for the Cuna Indians of the San Bias Archipelago.
Discussion: Dermomurex (Trialatella) cuna is the fifth- known member of its three-winged subgenus to be found in the western Atlantic. The other species include D. abyssicola (Crosse, 1865) from Guadeloupe, French An- tilles, D. glicksteini Petuch, 1987 from southeastern Flor- ida, D. kaicherae Petuch, 1987 from Yenezuela, and D. oxum Petuch, 1979 from the Abrolhos Archipelago, Bra- zil. Of the Atlantic species, D. cuna is closest to D. kaich- erae, but differs in being a more broad-shouldered shell with a proportionally lower spire, and in being a smooth- er, less sculptured shell lacking the broad, thick inter- varical cords and knobs of D. kaicherae (Petuch, 1987: plate 24, figures 17, 18). Of the known Trialatella species, D. cuna is closest to the Panamic D. cunninghamae (Berry, 1964), the type of the subgenus, and the two form an obvious cognate pair. The new Caribbean species differs from its Panamic cognate in being a more elon- gated, slender shell with a proportionally higher spire and less developed winged varices. The form and number of the body whorl cords and the structure of the intri- tacalx of the two species, however, are very similar.
Yokes (1975: plate 4, figures 3a, b) illustrated a smaller specimen of D. cuna from "Holandes Cav, off ("ape San Bias, Panama, 22 fathoms l)ut referred it to the Lesser Antilles species D. abyssicola. She later reillustrated the same specimen (Yokes, 1985: figures 13a, b). but this time referred the Panamanian shell to the Brazilian D. oxun^. This now well-known specimen of D. cuna, however, is a juvenile (with 6 varices) of only 9 mm length, and does not exhibit the adult proportions. Fully mature, three- winged specimens of D. cuna (approximately 13 mm) and D. oxuni (holotvpe 12.5 mm) are quite different, with D. oxum being a much broader, stockier shell with wider bodv whorl cords and elongated intervarical knobs. .Although similar to, and often confused with D. abys-
Figures 1-22. New gastropods from the Caribbean coast of Panama 1, 2. Turrilrtla marianopsis new species, liolotype, length 58 mm. L'SN'M 860523. 3. Turriletla marianopsis new species, paratype, length 52 mm. I .SNM 860524. t. 5. Chicarcn.s hilli new species, holotype, length 26 mm. I S.WI 860525 6, 7. Murcxiclla cdnardpauli new species, holotvpe. I'SNM 860529 8. \tnrex rubidus panamicus new subspecies, holotype, length 26 mm, I SNM 860528 9, 10. Dcrnionuircx (Trialatella) cuna neu species, holotype, length 14 mm, USNM 860527. 11. Valuta virescens Lightfoot. 1786, 43 min specimen from Cartagena. Colombia, tor
E. J. Petuch, 1990
Page 61
comparison with Valuta lacertina. 12. 13. Latirus cuna new species, holotype, length 46 mm, I SNM 860531. 14, 15. Mitra [Nebularia] leonardi new species, holotype, length 22 mm, USNM 860533. 16. Valuta lacertina new species, paratype, length 29 mm, IISNM 860538. 17, 18. Prunum leonardhilli new species, holotype, length 19 mm, I'SNM 860536. 19, 20. Oliva (Strephona) reticularis ernesti new species, holotype, length 38 mm, USNM 860535. 21, 22. Valuta lacertina new species, holotvpe, length 31 mm, USNM 860537.
Page 62
THE NAUTILUS, Vol. 104, No. 2
sicola, D. cuna is a larger, broader shell with a higher, more obvioiisK' stepped spire. The siphonal canals of botli D. oxum and D. ahyssicola are neither as elongated nor as well developed as that of D. cuna. and are not re- curved.
In the fossil record, D. cuna is most similar to D. antecessor Vokes, 1975 from the early Pleistocene of Costa Rica (Moin Formation) and southern Florida (Ber- mont Formation) This possible Pleistocene ancestor, however, differs from the Recent Blasian species in being a more elongated species with less developed varices and coarser corded body whorl sculpture.
Murcx Linnaeus, 1758
Murex rubidus panainictts new subspecies (figure 8)
Material examined: Holotype — Length 26 mm, trawled by commercial fishermen from 50 m depth off Portobelo, Panama, I'SNM 860528; Paratype 1— length 27 mm, same locality and depth as holotype, Leonard Hill col- lection, Miami, Florida.
Description: Shell small for genus, with fusiform body; spire high, elevated; body whorl and varices rounded; 3 large, thick varices per whorl; 2-3 narrow, elongated knobs in intervarical areas; body whorl, intervarical knobs, and varices ornamented with 12-14 large, raised spiral cords; thin spiral threads often present between spiral cords; siphonal canal extremely long and narrow, equal to length of shell body; base of siphonal canal ornamented with 2 small spines; aperture small, rounded; peristome ornamented v\ ith numerous large white teeth; shell color bright orange with 2 darker orange-tan bands, one around shoulder and one around body whorl-siphonal canal junc- tion; posterior half of siphonal canal brown; anterior half of siphonal canal pale orange-white.
Etymology: Named for Panama, the country of the type locality.
Discussion: Murex rubidus Baker, 1897 is now known to have a split distribution within the Caribbean region, with the nominate subspecies, M. rubidus rubidus. being found along the southeastern and western coasts of Flor- ida and the northern Bahamas (Radwin and D'Attilio, 1976:71), and with a small, isolated population, M. rubi- dus panamicus, being found along Caribbean Panama. Both populations may be relicts of a once wide-ranging Pleistocene species that has become biogeographically bisected and spatially reduced since the late Pleistocene. Several other Blasian species also share close morpholog- ical similarities with Bahamian gastropods. Included are the Blasian Chicoreus emihjae Petuch, 1987 and the Bahamian-Floridian C. florifer Reeve, 1846 and the Bla- sian Conus hilli n..>-p and the Bahamian Conus jucundus Sowerby, 1887 (= C. abbotti Clench, 1942).
Murex rulndus panamicus differs from the nominate subspecies in being a much more slender, more fusiform shell with a much higher, more protracted spire. The body whorl of A/, rubidus rubidus is rounded and glo-
bose, while the body whorl of M. rubidus panamicus is narrower and elongated.
Murexiella Clench and Farfante, 1945
Murexiella edwardpauli new species (figures 6, 7)
Material examined: Holotype — Length 15 mm, trawled by commercial fishermen from 50 m depth off Portobelo, Panama, USNM 860529; Paratype 1— length 15 mm, same locality and depth as holotype, USNM 860530.
Description: Shell small for genus, thin, delicate, with globose, inflated body; 6 varices per whorl, varices thin, with 6 large, recurved spines; intervarical areas orna- mented with 6 large spiral cords; intervarical cords and varices minutely squamose; siphonal canal proportion- ally very elongated, ornamented with 3 large, flattened spines per siphonal varix; shell consistentK pinkish-tan colored with 2 darker tan bands, one around shoulder and one around midbody; shoulder of body whorl slightly angled; aperture proportionally large, oval in shape.
Etymology: Named for Mr. Edward D. Paul of Miami. Florida.
Discussion: Murexiella edwardpauli is closest to Mu- rexiella macgintyi (Smith, 1938) from Florida and the Bahamas, but differs in being a much smaller, more delicate species with a much more globose body whorl, less angled shoulder, and proportionally longer and nar- rower siphonal canal. Murexiella edivardpauli is also similar to M. leonardhilli Petuch, 1987 from Brazil, but differs in being a much smaller shell with thinner, less crassate varices. In the eastern Pacific, M. edwardpauli is very similar to M. keenae Vokes, 1970, but differs in being a smaller shell with a proportionalK longer si- phonal canal. Based on shell morphology, M. keenae and M. edivardpauli can be seen to be ver\' closeK' related and represent Panamic-Caribbean cognates.
Fasciolariidae Peristerniinae Latirus Montfort, 1810
Lalirus cuna new species (figures 12, 13)
Material examined: Holotype — Length 46 mm, traw led by commercial fishermen from 60 m depth off Portobelo, Panama, USNM 860531; Paratype 1— length 42 mm, same locality and depth as holotype, USNM 860532; Paratope 2 — length 45 mm, same localits and depth as holotype, collection of Leonard Hill, Miami, Florida.
Description: Shell elongately fusiform, w ith high, sca- lariform spire and narrow protracted siphonal canal; shoulder sharply angled, with rounded, spikelike knobs; whorls with 8 narrow, raised axial ribs per whorl; axial ribs (>\erlaid with 5 large, thick spiral cords; 2 spiral ct)rds at shoulder largest and best developed, projecting farthest from shell body; areas between large cords or-
E. J. Petuch, 1990
Page 63
namented with numerous very fine cords and spiral threads; siphonal canal ornamented with 4 large spiral cords; areas between large siphonal cords ornamented with numerous fine cords and threads; interior of aper- ture with 10-12 large, beaded cords; edge of lip fineK crenulated, with crenulations corresponding to fine spiral cords and threads on shell surface; narrow umbilicus present; shell color bright orange-tan; large cords of body whorl, spire, and siphonal canal white; interior of ap- erture orange.
Etymology: Named for the Cuna Indians of the San Bias Islands,
Discussion: Latiriis cuna somewhat resembles the wide- spread Caribbean L. cariniferiis Lamarck, 1822, but dif- fers in being a more slender, elongated shell with a nar- rower, more protracted siponal canal, and in having a more sharpK -angled shoulder with proportionally larger and sharper shoulder knobs. The new Blasian species is also similar to the Panamic L. ccntrifugus (Dall, 1915), but differs in being a more slender, elongated shell with a proportionally longer siphonal canal. Otherwise, both L. centriftigus and L. cuna share the same type of sharp- ly-angled shoulder, large shoulder knobs, and strongly projecting shoulder cords. I feel it is safe to assume that L. cuna and L. ccntrifugus form a cognate species pair.
Volutacea
Mitridae
Mitra Lamarck, 1798
Nebularia Swainson, 1840
Mitra {Nebularia) leonardi new species (figures 14, 15)
Material examined: Holotype — Length 22 mm, trawled by commercial fishermen from 60 m depth off Portobelo, Panama, USNM 860533; Paratype 1— length 20 mm, same locality and depth as holotype, USNM 860534.
Description: Shell narrow and elongated, fusiform; spire high, protracted, scalariform; suture indented, producing narrow shoulder area and stepped spire whorls; body whorl ornamented with 12 large, thick spiral cords; col- umella with 4 plications, with posteriormost plications being largest; shell color white, heavily overlaid with wide, reddish brown vertical flammules; reddish-brown flammules often coalesce into large, longitudinal patches; some specimens (holotype) with thin white band around midbody; aperture thin, narrow, roughly one-half length of shell.
Etymology: Named for Mr. Leonard C. Hill of Miami, Florida who kindly donated the type material.
Discussion: In the Caribbean, Mitra leonardi is closest to M. semiferrtiginea Reeve, 1845, from the Bahamas, but differs in being a smaller, much narrower shell with a proportionally larger aperture. The two species also differ in color; with M. semiferruginea being colored bright yellow with dark, blackish-brown flammules and with M. leonardi being white with reddish-brown flam-
mules. In the eastern Pacific, M. leonardi is closest to M. sphoni Shasky and Campbell, 1964, especially in size and color, but differs in having a more scalariform, stepped spire. Mitra sphoni and M. leonardi. together, are another example of a Panamic-Caribbean cognate species pair.
Olividae
Oliva Bruguiere, 1789
Strephona Morch, 1852
Oliva (Strephona) reticularis ernesti new subspecies
(figures 19, 20)
Material examined: Holotype — Length 38 mm, trawled from 40 m depth on silty sand bottom off Portobelo, Panama, USNM 860535; Paratypes 1-3— lengths 37-41 mm, same locality and depth as holotype, Petuch col- lection.
Description: Shell average size for subgenus, cylindri- cal, with only slightly rounded shoulder; spire low; body whorl colored yellowish-tan, overlaid with dense, close- packed pattern of small, dark brown triangles and zig- zags; 2 wide bands of darker brown triangles present around bod>' whorl, one around anterior one-third and one around area just posterior of midbody line; sutural area marked with large, evenly-spaced yellow patches and numerous fine black hairlines; spire whorls glazed- over with dark purple-brown enamel; aperture and col- umellar area white; columella with 15-20 thin plicae; fasciole yellow-tan marked with 2 rows of large dark brown checkers; protoconch proportionally small, col- ored dark purple-brown.
Etymology: Named for Mr. James Ernest of Balboa, Panama, who collected the type lot.
Discussion: Oliva reticularis ernesti from the Blasian area differs from O. reticularis reticularis Lamarck, 1810, from the Bahamas and West Indian Arc, in being a more straight-sided, cylindrical shell with a much lower spire. The new subspecies is also a darker-colored shell with a finer and denser pattern of triangle markings. Oliva re- ticularis ernesti occurs with, and has often been confused with, Oliva hewleiji Marrat, 1871. That species, however, is a much larger shell (av. 55 mm) with a proportionateK' higher spire and larger protoconch. Oliva bewleyi has a much more diffuse color pattern, with the triangle mark- ings and zigzags having a "smeared" look. The triangle markings of O. reticularis ernesti. on the other hand, are consistently clear and distinct. Although O. bewleyi is now known to range from Panama to Santa Marta, Colombia (Petuch & Sargent, 1986:126), O. reticularis ernesti appears to be restricted to the Blasian area.
Marginellidae
Prunum Hermannsen, 1852
Prunum leonardhilli new species
(figures 17, 18)
Material examined: Holot\ pe — Length 19 mm, trawled from 60 m depth h\ commercial fishermen, off Portobelo,
Page 64
THE NAUTILUS, Vol. 104, No. 2
Panama, USNM 860536. Paratypes 1, 2— lengths 18 mm and 19 mm, same locality and depth as holotype, Leon- ard Hill c'ollet'lioM.
Description: Shell elongated, ovate, somewhat inflated; base of shell flattened anteriorly, bordered by thickened parietal callus that connects with thickened outer lip around anterior end; margins of shell thickened; spire relatively low; columella with 4 very large plications that extend beyond aperture region onto shell base; aperture narrow, slightly wider at anterior end; shell pale bluish- gray color with 2 darker gray bands; thickened lip and basal callus white; junction of body whorl and lip marked by thin \ ellow line; body whorl-lip junction area suffused with pale yellow color; interior of aperture bright orange- brown; protoconch and early whorls pale orange-tan.
Elymology: Named for Mr. Leonard C. Hill of Miami, Florida, who kindly donated the holotype.
Discussion: Prttruim Iconardliilli is very similar to P. curtum (Sowerby, 1832) from the coasts of Ecuador and Peru, as both species share the same shell shape, shell size, and form of the columellar plications. Pritnum cur- tum. however, is a yellow shell with a pale orange outer lip, while P. leonardhilli is basically a blue-gray shell with a white outer lip. Regardless of color, the two species appear to be cognates. In the Caribbean P. leonardhilli is closest to P. prunum (Gmelin, 1791), which is abundant and widespread along the coasts of Colombia and Ven- ezuela. The new Panamanian species differs from the common P. prunum, however, in being a smaller, more globose, and less elongated shell, with much larger col- umellar plications. The columellar plications of P. pru- num do not extend as far onto the shell base as do those of P. leonardhilli. The two species also appear to be ecologically exclusive, with P. prunum preferring the organic-rich coastal muds and P. leonardhilli preferring fine particulate carbonate bottoms in offshore areas. Prunum leonardhilli is sympatric with another Blasian marginellid endemic, Persicula weheri Olsson and McGinty, 1958.
Volutidae Volutinae Valuta Linnaeus, 1758
Valuta lacerlina new species (figures 16, 21, 22)
Material examined: Holotype — Length 31 mm, trawled by commercial fishermen from 100 m depth off Porto- belo, Panama. USNM 860537; Paratype 1— length 29 mm, same depth and locality as holotype, USNM 860538;
Paratype 2 — length 30 mm, same depth and locality as holotype, Leonard Hill collection.
Description: Shell very small for genus, averaging only 30 mm in length; shell outline broadly fusiform, tapering toward anterior end; spire elevated; shoulder rounded, ornamented with 10-12 low, riblike knobs; body whorl ornamented with 20-24 horizontally-arranged, deeply incised spiral sulci and numerous thin longitudinal plicae; sulci and plicae intersect to produce strong cancellate sculpture pattern; intersection of pair of sulci and plicae producing large, raised bead, giving entire surface of body whorl pebbly appearance; subsutural area orna- mented with 6 large spiral cords; shell color yellowish- tan overlaid with numerous minute brown dots and 3 bands of large light brown rectangular patches, one along suture, one below shoulder, and one around anterior end; protoconch proportionally large, composed of 2 whorls, flattened and somewhat discoidal; protoconch asymmet- rical in form, with first whorl projecting dorsally out of alignment with second whorl; protoconch light brown in color; aperture wide, yellow to pale orange in interior; columella with 10 large, thin, smooth plications; thin, small, secondary plications sometimes present between anteriormost primary plications; outer lip of adults thick- ened, marked with 10-12 small brown spots; operculum unknown.
Etymology: "Little lizard", in reference to the new species' beaded appearance, which resembles lizard skin.
Discussion: Valuta lacertina is the smallest-known Va- luta s.s. and is also the deepest-dwelling, having been trawled from 100 m depth. All other Valuta s.s., and members of the closely-related Falsilyria Pilsbry and Olsson, 1954 species complex, prefer depths of 30 to 50 m and some are often collected by SCL'BA diving (such as Falsilyria .■iundcrlandi Petuch, 1987 from 10 m depth off Utila Island, Honduras). At Cartagena, Colombia, the closely-related Valuta virescens Lightfoot, 1786 is found in shallow subtidal depths and frequently is collected as beach specimens.
Valuta lacertina is most similar to the other Blasian endemic volute, V. lindae Petuch, 1987 (figure 23), but differs in being a smaller, more heavily scuptured shell with a more rounded shoulder. The sculpture pattern of the two species also differs, with V. lacertina having a pebbly, beaded surface texture and with V. lindae having stronger longitudinal plicae that give the shell a wrinkled look. The shoulder knobs of V. lacertina are weak and rounded, while those of \'. lindae are strong, angled, and sharpl) pointed. Valuta lindae is also a more brightly colored shell, being an intense yellow or yellow-orange and having large, dark brown spots in rows around the bodv whorl. Valuta lacertina, on the other hand, is a
Figures 2:i-il. \pu Volutes (Xoliilidae). Cones (Conidae). and Turrids (Turridae) from the C:aribbean coast of Panama 23. Voliila lindae Petiich, 1987, 46 mm lioiotypc from Bocas del Toro, Panama, for comparison with Vohita lacertina. 21, 2,'j. Falsilyria erne.sti new species, holoU pc |pni;lli ."^4 mm, USNM 860539. 26, 27. Conus grariarius panaminis new subspecies, hnioh |>c l.-tigth
E. J. Petuch, 1990
Page 65
24 mm, IISNM 860543, 28. 29. Conus crnesti new species, liolotype, length 29 mm, USNM 860542, 30, 31. Contts brunneofxlaris new species, liolotype, length 14 mm, LISNM 860541, 32, 33. Conus poriobeloensis new species, hulutype, length 31 mm. USNM 860545, 34, 35. Conus rosemaryae new species, holotype, length 25 mm, L'SNM 860546. 36, 37. Conus hilli new species, hololype, length 21 mm, USNM 860544. 38, 39. Knefastia hilli new species, holotype, length 50 mm. I'SNM 860548. 40. 41. Fusiturrirula sunderlandi new species, holotype, length 33 mm, USNM 860547,
Page 66
THE NAUTILUS, Vol. 104, No. 2
drab little shell, being a pale tan or yellowish-tan and lacks the large, scattered brown spots seen on V. lindac. Both species, however, have the same fine-dotted pattern that covers the entire shell, although the dots of V. lindae are proportionally larger and darker. The protoconchs of the two species also differ significantly, with that of V". lindae being inflated and cylindrical in form, while that of V. lacertina is flattened and asymmetrical. Balhy- metrically, the two species also differ, with V. lacertina living at depths of 100 m or deeper and with V. lindae preferring much shallower areas of 20 to 50 m depth.
Valuta lacertina is also similar to the well known V. virescens (figure 11), which ranges from off Nicaragua to Santa Marta, Colombia, and the two species appear to represent a pair of bathymetric siblings. As in V. lindae, V. virescens prefers shallower depths, ranging from 5 to 35 m. The substrate preferences of these three closely-knit species also appear to differ, with V. lacer- tina and V. lindae preferring coralline algal rubble and carbonate bottoms and with V. virescens preferring muddy, organic-rich bottoms. Valuta virescens from the organic detrital and reducing substrates within the Golfo de Uraba, on the Panama-Colombia border, are stained black from reduced iron compounds and are often en- crusted with iron sulfide Valuta lindac and \'. lacertina. from the cleaner carbonate substrates of the Blasian area, are usually shiny and uncoated by iron compounds.
Morphologically, V. virescens differs from V. lacertina in being a larger shell with a smooth shell sculpture that lacks the pebbly beading. The basic shell coloring also differs between the two species, with V. virescens being a characteristic green or greenish-gray while V. lacertina is a pale yellow-tan. The protoconch of V. virescens is proportionally smaller than that of V. lacertina, being narrow and cylindrical in form. The protoconch of V. lacertina is large for such a small shell, and is flattened and almost discoidal in form. Interestingly enough, al- though V. virescens is the largest species of the Pana- manian-Colombian Valuta species complex, it has a pro- portionally much smaller protoconch than those of its diminutive relatives, V. lindae and V. lacertina.
Falsilyria and Pilsbry and Olsson, 1954
Falsilyria ernesti new species (figures 24, 25)
Material examined: Holotype — Length 54 mm, trawled by commercial fishermen from 65 m depth off Portobelo, Panama, USNM 860539; Paratype 1— length 55 mm, same locality and depth as holotype, USNM 860540; Paratype 2 — length 54 mm, same locality and depth as holotype, Leonard Hill collection, Miami, Florida.
De.scription: Shell narrow, elongated, fusiform, thick and heavy; spire elevated, protracted; spire whorls slight- ly convex in outline; whorls ornamented with 8-10 large, rounded, axial plications; large plications overlaid with numerous thin, riblike plications; shoulder angled, bor- dered by single large spiral cord; subsutural areas sculp- tured with 3 large spiral cords; subsutural spiral cords
intersect with thin axial riblets to produce beaded texture on shoulder and spire; bod\ whorl shiny, polished; an- terior end sculptured with 5-6 large spiral Cf)rds; colu- mella slightly arcuate, with 11-12 thin, smooth plica- tions; outer lip of adults thickened, projecting posteriorward; protoconch proportionally large, round- ed, domelike; shell color pale salmon-yellow with 2 wide bands of brown and pale purple checkers and spots, one around midbody and one around anterior end; midbody band overlaid with 4-6 brown spiral hairlines and nu- merous tiny brown vertical flammules; anterior band similarly marked with 5 brown hairlines and tiny vertical flammules; salmon-yellow areas between wide colored bands completely overlaid with closely-packed, tiny or- ange-brown speckles; protoconch light tan; columella and interior of aperture pale salmon; edge of lip yellowish- white, marked with evenly-spaced dark brown spots.
Etymology: Named for Mr. James Ernest of Balboa, Panama, who collected the type lot.
Discussion: Of the Fasilyria species complex, F. ernesti is the southernmost known member, and its discovery came as a surprise to me. Previously (Petuch, 1987:62), I had stated that the genus was restricted to the coasts of Honduras and northern Nicaragua. The new Blasian species, therefore, represents a considerable range ex- tension for the complex. Of the eight known Falsilyria species, F. ernesti is most similar to F. demarcoi (Olsson, 1965) from Honduras, but differs in being a much small- er, more slender and elongated shell, with a much more sharply-angled shoulder. The Honduran F. demarcai is also a much more brightly colored shell, having a deep orange base tone. The Blasian F. ernesti, on the other hand, is a less colorful shell, having a base tone of pale salmon-yellow. In shape and in having a small adult size, F. ernesti is also similar to F. hara.seivychi Petuch, 1987, from off Roatan Island. The new species differs from F. hamseioychi. however, in having a salmon-\ellow base color instead of white, and in lacking the wine-red flam- mules and black and white checkered bands of F. harase- wychi. The Roatan species has distinctive, characteristic beaded columellar plications, while those of F. ernesti are smooth.
Conacea Conidae Canus Linnaeus, 1758
Conus brunneofilaris new species (figures 30, 31)
IVIaterial examined: Holotype — Length 14 mm, trawled bv commercial fishermen from 65 m depth off Portobelo, Panama, IISNM 860541.
Description: Shell small, elongately conical, thin, fra- gile; shoulder sharpK angled, carinated; carina faintly undulating; spire moderately elevated, with stepped whorls; body whorl shiny and polished; anterior tip en- circled with 6 small spiral cords; aperture narrow, slightly w idcr at anterior end; protoconch proportionalK large.
E. J. Petuch, 1990
Page 67
mammillate; shell color bright golden-tan with wide niidbod) band of large white patches and dark brown flammules; anterior tip marked with large white flam- mules; golden-tan and white base color overlaid with 21 extremely fine, hairlike, dark brown spiral lines; shoulder and spire white with large, evenly-spaced, dark brown flammules; spire flammules extend over edge of shoulder carina onto body whorl; interior of aperture white; pro- toconch and early whorls bright yellow.
Etymology: "Brown threaded", in reference to the prominent, evenly-spaced, thin brown lines that encircle the body whorl.
Discussion: Conns bninneofilaris. with its distinct brown spiral lines, resembles no other known Caribbean or Pan- amic cone shell. In shape and size, this unusual new species is most similar to C. magnottei Petuch, 1987 from Roatan Island, Honduras, but differs in having a bright golden-tan base color instead of the pink and purple color ot C. magnottei, and in having the overlay color pattern of brown lines, which is lacking in the Honduran species. The spire flammules of C. magnottei are also larger and more irregular than those of C. bninneofilaris and do not extend onto the body whorl.
Coj}tis ernesti new species
(figures 28, 29)
IMaterial examined: Holotype — Length 29 mm, trawled by commercial fishermen form 65 m depth off Portobelo, Panama, USNM 860542; Paratype 1— length 31 mm, same locality and depth as holotype, Kevan Sunderland collection.
Description: Shell slender, tapering rapidly toward an- terior tip; shoulder wide, sharply angled; spire high, el- evated, scalariform; shell smooth, polished, with deeply- impressed spiral sulci around anterior end; aperture straight, narrow; shell color white with 12-20 rows of small brown dots and dashes; rows of dots often aligned to form large brown vertical flammule; dotted pattern overlaid with variable amounts of amorphous lighter brown patches; clear band, with only one or two rows of dots, present around midbody; some specimens (ho- lotype) with brown patches coalescing into 2 broad bands, one above, and one below, midbody; anterior tip of shell white; spire whorls white with numerous, evenly-spaced crescent-shaped flammules; early whorls brown; interior of aperture white.
Etymology: Named for Mr. James Ernest of Balboa, Panama, who collected the holotype.
Discussion: Conus ernesti is most similar to Conns cin- gulatus Lamarck, 1810 from the Caribbean coast of Co- lombia, but differs in being a smaller, lighter colored shell with a much higher, scalariform spire. The lower- spired Conus cingulattis is a rough-textured shell, with the body whorl being heavily sculptured with incised sulci and raised spiral threads. Conns ernesti, on the other hand, is a smooth, almost polished shell, with in-
cised sulci onlv on the anterior end. The dark purple- brown C. cingnlatus has a purple aperture, whereas the white and light brown C. ernesti has a white aperture. The new species is also similar to C. garciai daMotta, 1982 from the Caribbean coast of Honduras, but differs in being a nuich smaller shell with rows of brown dots. Like C. cingnlatus, C. garciai is also a rough-textured shell, heavily ornamented with raised threads, and differs greatly from the smooth C. ernesti. Together, C. garciai, C. ernesti, and C. cingnlatus form an interesting species complex, with each being restricted to a separate mol- luscan assemblage.
Conns granarins partamicus new subspecies (figures 26, 27)
Material examined: Holotype — Length 24 mm, trau led by commercial fishermen from 40 m depth off Portobelo, Panama, USNM 860543; Paratype 1— length 28 mm, same locality and depth as holotype, Leonard Hill col- lection.
Description: Shell subpyriform, tapering abruptK to- ward anterior end; shoulder sharply angled, subcarinat- ed; spire very high, elevated, protracted; shoulder pe- riphery and spire whorls heavily ornamented with numerous large, rounded beads, producing distinctly co- ronated spire; body whorl shiny, ornamented with IS- IS evenly-spaced rows of tiny pustules; shoulder and subsutural area flattened, producing pronounced stepped spire; shell color pale lilac, often overlaid with large, vertically-oriented, light tan patches; interior of aperture violet.
Etymology: Named for Panama, country of the type locality.
Discussion: Conus granarins panamicus may represent an isolated population of the wide-ranging C. granarins granarins, which ranges from northern Colombia into the Gulf of Venezuela. The new subspecies differs from the nominate subspecies in being a smaller, stumpier, more biconically-shaped shell with a proportionally higher and more scalariform spire. Conus granarins panamicus also lacks the spiral rows of dots that characterize the color pattern of C. granarins granarins, and is a much paler, less colorful shell. Some specimens of C. granarins panamicus are uniformly pale lilac (like the holotype), while others have large tan patches. Although the nom- inate subspecies appears to prefer muddy, siliciclastic sediment bottoms with large amounts of organic matter, C. granarins panamicus prefers coralline rubble and carbonate sand bottoms.
It is conceivable that C. granarins panamicus may, in fact, be a full species, closely related to, but distinct from, C. granarins granarins. The new taxon may be part of a Honduras-Panama-Colombia species complex, much as in the case of Conns garciai-ernesti-cingulatns. This species complex, then, would comprise the Honduran C. harlandi Petuch, 1987, the Panamanian C. panamicus.
Page 68
THE NAUTILUS, Vol. 104, No. 2
and the Colombian C. granarius, with each being part of a localized, eiideiiiic fauniile.
Coriua liilli new species (figures 36, 37)
Material examined: Ilolotype— Length 21 mm, trawled b\ commercial fishermen from 26 mm depth off Por- lobelo, Panama, USNM 860544.
Description: Shell stocky, broad across shoulder; spire low, flattened; shoulder sharpK -angled, subcarinated; shoulder and spire whorls ob.soletely coronated, with low, evenly-spaced undulations along periphery; body whorl very smooth, polished, shiny; anterior tip with 10 small, slightK raised spiral cords; shell color deep purple-blue w ith blotch) , light blue band around midbod> ; light blue midbody band marked with 4 rows of tiny, closely-spaced reddish-brown dots; spire whorls white with evenly- spaced, large dark brown cre.scent-shaped flammules; protoconch mammillate, protracted, light orange in col- or; aperture narrow, purple within.
Etymology:
Florida.
Named for Mr. Leonard C. Hill of Miami,
Discussion: Conus hilli is most similar to, and appar- ently is a close relative of, Conus kulkulcan Petuch, 1980 from the Bay Islands of Honduras. The new species dif- fers from C. kulkulcan, however, in having a lower, flatter spire, and in having a squatter, less elongated shape. The spire whorls and shoulder of C. kulkulcan are marked with numerous fine, dark brown hairlines. but these are absent on C. hilli. Conus kulkulcan is also a textured shell, having spiral rows of tiny pustules around the body whorl. Conus hilli, on the other hand, is an unte.xtured shell, having a highly polished, shiny body whorl. As in the case of the last two new cones in this paper, Conus hilli forms an interesting species trio with closely- related Honduran and Colombian species. This complex, then, includes C. kulkulcan from Honduras, C. hilli from Panama, and C. colomlrianus Petuch, 1987 from northern Colombia. Other related species in this close-knit Caribbean complex include C. jucundus Sow- erby, 1887 (= C. abbotti Clench, 1942) and C. inconstans E. A. Smith, 1877 from the Bahamas, C. arangoi Sarasua, 1977 from Cuba, C^ay Sal, and Turks and Caicos, C. cardinalis Hwass, 1792 and C. cidaris Kiener, 1845 from Hispaniola and the West Indian Arc, C. mayaguensis Nowell-Usticke, 1968 from the Dominican Republic and Puerto Rico, C. harasewychi Petuch, 1987 from Palm Beach, Florida, and possibly C. abrolhosensis Petuch, 1987 from the Abrolhos Archipelago of Brazil.
Conus portobeloensis new species (figures 32, 33)
Material examined: Holotype — Length 31 mm, Irawled by commercial fishermen from 30 m depth off Portobclo, Panama, USNM 860545.
Description: Shell elongate, subpyriform, with low spire; earliest, postnuclear spire whorls protracted, becoming flattened during ontogeny; shoulder sharpK angled, edged with small but distinct carina that projects be>ond shoul- der margin; body whorl smooth and shiny, with 20 large, raised cords around anterior quarter; spire whorls smooth; shell color white, marked with intermittent longitudinal flammules of pale orange-tan; longitudinal flanmniles, in turn, overlaid with scattered darker tan dots and dashes; anterior end of body whorl pale \ellow-orange; spire white, with scattered amorphous flammules of dark or- ange-tan; midbody marked with clear white band; in- terior of aperture white; protoconch and early whorls dark orange; periostracum thin, tan, silky in texture.
Etymology: Named for the city of Portobelo, off of which the holotype was collected.
Discussion: At first glance, Conus portobeloensis ap- pears to be related to the C. garciai-ernesti-cingulatus species complex, particularly in color pattern. Based upon the presence of a shoulder carina and a subp\ rif orm body form, however, C. portobeloensis appears to be more closely related to C. commodus A. Adams, 1854 (reil- lustrated by Petuch, 1987: plate 10, figures 18, 19) from off Roatan Island, Honduras, and may be the Panama- nian analogue. Conus portobeloensis differs from the Honduran species in being a larger, more elongated shell and in having a color pattern of orange-tan flammules and dots. The new Panamian species is also similar to C. paraguana Petuch, 1987 from the Gulf of Venezuela, as both species have an orangish dashed color pattern and both have a clear white midbody band. Conus porto- beloensis differs from C. paraguana. however, in being a much larger, broader species with a wider and more sharply angled shoulder.
Conus roseniaryac new species
(figures 34, 35)
material examined: HoIot>pe — Length 25 mm, trawled by commercial fishermen from 85 m depth off Portobelo, Panama. USNM 860546; Paratype 1— length 24 mm, same depth and locality as holotype, Leonard Hill col- lection, Miami, Florida.
Description: Shell small for genus, extremely pyriform, turnip-shaped, wide across shoulder; shoulder carinated; spire moderateK protracted, with concave whorls; body whorl polished and shiny, faintly ornamented with nu- merous low threads; spire whorls smooth; anterior third of body whorl sculptured with 10 deeply-impressed wide spiral sulci; body whorl white, overlaid with dense net- work of large, amorphous, bright yellow-orange flam- nuiles; some specimens (parat>pe) overlaid with .scat- tered rows of dots; spire whorls white with scattered large, amorphous yellow-orange patches and flammules; ant(>rior tip of shell pale orange; protoconch and early w horls orange; interior of aperture white; periostracum thin, transparent tan, smooth.
E. J. Petuch, 1990
Page 69
•12
10
Figure 42. Map of the southwestern Caribbean Sea and the Panamanian Isthmus, show iiig the ilistribution of Caribbean molluscan faunal subregions. H = Honduran Subregion; B = Blasian Subregion; CV = Colombian-Venezuelan Subregion (taken, in part, from Petuch, 1988). Blasian geographical landmarks include the Laguna de Chiriqui (C), Portobelo (P), San Bias Archipelago (S), and the Golfo de Uraba (U) As shown here, the Blasian Subregion may extend northward to the Costa Rica-Nicaragua border area, in the vicinity of San Juan del Norte, Nicaragua.
Etymology: Named for Ms. Rosemary Adams of Sun- nymead, California, who assisted Mr. James Ernest in the collection of the new Blasian species.
Discussion: Of the known Blasian Conidae, Conns rose- maryae is certainly one of the most distinctive. The pyr- iform turnip shape of this new species is unique among the Caribbean Panamanian cones. In general body form, C. wsemaryae most closely resembles C. gibsonsmitho- rum Petuch, 1986 from the Goajira Peninsula of Colom- bia and the Gulf of Venezuela, but differs in being a larger shell with a more elongated, tapered body whorl, and in being narrower across the shoulder. Although both C. gibsonsmithorum and C. wsemaryae have color va- rieties with rows of dots, C. rosemaryae is a more heavily patterned, more colorful species, with large orange flam- mules (as in the holotype) covering most of the shell The new species is also similar to C. sennottorum Rehder and Abbott, 1951 from the Gulf of Mexico off Yucatan, but differs in being a smaller, more slender, and more brightly colored shell.
Turridae
Fusittirricula Woodring, 1928
Fusititrricula sundcrlandi new species (figures 40, 41)
Material examined: Holotype — Length 33 mm, trawled by commercial fishermen from 70 m depth off Portobelo, Panama, USNM 860547.
Description: Shell extremely elongated, slender, and fusiform; spire very elevated and protracted, turriculate; shoulder sharply-angled, with 12 oval-shaped knobs per whorl along periphery; subsutural area sloping; body whorl below shoulder knobs ornamented with 10 large beaded spiral cords; subsutural area ornamented with numerous extremely fine spiral threads; margin of suture bordered bv bands of small, closely-packed oblong pus- tules; siphonal canal elongated, narrow, straight, orna- mented with numerous fine, beaded, spiral threads, shell color uniformly pinkish-tan; aperture and columella white
Page 70
THE NAUTILUS, Vol. 104, No. 2
Etymology: Named for Mr. Kevan Suntlerlaml of Fort Lauderdale, Florida, who kindly donated the holotype
Discussion: Fusiiurricula sunderlandi is most similar to the Panamic species, F. armilda (Dall, 1908), but dif- fers ill heiii^ a more slender, fusiform shell with a more elongated body whorl. In F. armilda. the body whorl pinches-in abruptly at the junction with the siphonal canal, while in C sunderlandi, the body whorl tapers gradually into the siphonal canal. The two species pos- sibK form a cognate pair.
Knefasiia Dall, 1919
Knefastia hilli new species (figures 38, 39)
Material examined: Holot\pe — Length 50 mm, trawled bv commercial fishermen from 70 m depth off Portobelo, Panama, USNM 860548.
Description: Shell large, robust, fusiform; spire very high, elevated, distinct!) turriculate and scalaritorm; subsutural area flattened, producing stepped spire whorls; whorls ornamented with 8 large, rounded, elongated, \ari.\-like axial knobs; body whorl ornamented with 12 large, pustulated spiral cords with one or two fine, pus- tulated secondary cords in between; pustulated cords overlie large axial knobs; siphonal canal short, stubby, ornamented with 8 large, pustulated cords; fine cords and threads present between main siphonal cords; outer lip with numerous lirae along inside edge; anal notch small, narrow; shell color orange-brown with darker brown knobs; primary cords on spire, body whorl, and siphonal canal white or light tan; body whorl-siphonal canal junction marked with wide, dark brown band; an- terior end of siphonal canal circled by wide, dark brown band; aperture and columella pale orange-tan.
Etymology: Named for Mr. Leonard C. Hill of Miami, Floritla.
Discussion: Knefastia hilli is the first-known living At- lantic species of this primarily Panamic genus, Knefastia hilli is most similar to K. olivacea (Sowerby, 1833), which ranges from the Gulf of California southward to southern Ecuador. The new Caribbean species differs from K. olivacea in being a smaller shell with larger and more pronounced a.xial knobs, and in having finer and more numerous spiral cords. The two species, however, are very similar and, no doubt, represent Panamic-Carib- bean cognates.
ACKNOWLEDGEMENTS
I thank Mr. Leonard Hill of Miami, Florida, for the donation of the valuable research material collected bv
Mr. James Ernest. Thanks also to Mr. Kevan Sunderland, Fort Lauderdale, Florida, for the donation of the new Fusiturricula species. Special thanks go to Mrs. Cynthia Mischler, Department of Geology , Florida Atlantic Uni- versity, for patiently typing the manuscript and to Mr. William Lyons, Division of Marine Resources, Florida Department of Natural Resources, for valuable ocean- ographic data and critical review.
LITERATURE CITED
Houbrick, J. R. 1968. A survey of thf littoral marine mollusks of the Caribbean coast of Costa Rica Thf Wliger 11(1): 4-23.
Olsson, A. A. and T. L McGinty 1958 Recent marine mol- lusks from the Caribbean coast of Panama with the de- scription of some new genera and species. Bulletins of American Paleontology .39(177):5-.59.
Petuch, E. J. 1980. A relict caenogastropod fauna from north- ern South America. Maiacologia 20(2)307-347,
Petuch, E. J. 1981. A voiutid species radiation from Northern Honduras, with notes on the Honduran Caloosahatchian Secondary Relict pocket Proceedings of the Biological Society of Washington 94(4): 1 1 10-1130.
Petuch, E. J. 1982. Geographical heterochrony: contempo- raneous coexistence of Neogene and Recent molluscan faunas in the Americas. Palaeogeography, Palaeoclima- tology, and Palaeoecology 37:277-312.
Petuch, E. J. 1987. New Caribbean molluscan faunas The Coastal Education and Research Foundation. (Charlottes- ville, VA, 1.54 p
Petuch. E J. 1988 Neogene histor\ of tropical .\merican mollusks. The Coastal Education and Research Foimda- tion, Charlottesville, VA, 217 p
Petuch, E. J. and D. M. Sargent. 1986. Atlas of the living olive shells of the world. The Coastal Education and Re- search Foundation, Charlottesville. WA, 253 p
Radwiii, G. E. 1969. A Recent molluscan fauna from the Caribbean coast of Panama Transactions of the San Diego Society of Natural History 15(14):229-2.36.
Radwin, G E. and A. D'AttiJio. 1976. Murex shells of the world. Stanford University Press, Stanford, CA, 284 p.
Valentine, J. W. 1973. Evolutionary paleoecology of the ma- rine biosphere Prentice-Hall, Inc , Englewood, NJ, 511 p.
\ ernu'ij. i'. J 1978. Biogeography and adaptation: patterns oi marine life Harvard llni\ersit\ Press. C'ambridge, M.'^, 332 p,
Vokes, E, H, 1975, Cenozoic Muricidae ol the Western M- lantic Region. Part VI Aspella and Dcrrnomurex. Tulane Studies in Geology and Paleontology 11(3):121-162.
\'okes, E. H. 1985. Review of the West Coast Aspelloids Aspella and Dermomurex (Gastropoda: Muricidae), with the Descriptions of Two New Species. The Veliger 27(4): 430-439
Whilmore, F C and R H Stewart 1965 Miocene mammals ami Central .•\meritan seawa\s Science 1 48: 1 80- 1 8.5.
Wooilring, W. P. 1966 The I'anania land bridge as a sea barrier Proceedings ol the American Philosophical Society 110 42.5-43.3.
THE NAUTILUS 104(2):71-75, 1990
Page 71
Morphological Comparisons of the Species of Megapallifera (Gastropoda: Philomycidae)
H. Lee Fairbanks
Pennsylvania State I'niversit) Beaver Campus Monaca, PA 1.5061, USA
ABSTRACT
Specimens of all three species of Megapallifera. M mutabilis. M. uetherbyi. and M. ragsdalei. were collected from their t\ pe localities. The external morphology and reproductive s\stem anatomy of each of these species was compared. Mantle color and pattern of M. mutabilis is different from those of M. weth- erbxji and M. ragsdalei. Differences among the three species in penial anatoms and in morphology of the lobes in the upper atrium support ta.\onomic separation of the three species.
Keij words: Philomycidae; Megapallifera, morphology; re- [jroductive-system anatomy.
INTRODUCTION
The Philomycidae are a family of terrestrial slugs native to the eastern and south-centra! United States and eastern Asia. There are three genera in the famiK : Philomycus, Pallifera, and Megapallifera. The slugs in the genus Philomtjciis are large and have a dart sac and dart, those in the genus Pallifera are small and lack the dart sac and dart. The slugs in the genus Megapallifera also lack the dart sac and dart and were first placed in the genus Pallifera. Hubricht (1956) established Megapallifera as a subgenus of Pallifera, and cited five characteristics for its species: (1) gray or white foot margins, (2) ribbed jaw, (3) large size, (4) chevron-shaped transverse bands on the mantle, and (5) a pilaster extending from the lower vagina into the upper atrium. The latter three charac- teristics separated Megapallifera from Pallifera. Hu- bricht (1976) elevated Megapallifera to generic rank, with M. mutabilis (Hubricht, 1951), as the type species, and included M. wetherbyi (Binney, 1874) and M. rags- dalei (Webb, 1950). Webb (1950, 1951) discussed the reproductive-system anatomy of M. ivetherbiji and M. ragsdalei (as a species and subspecies respectively of Eitmelus), but data concerning the internal anatomy of the atria and penes were incomplete or absent. When Hubricht described M. mutabilis, he did not figure the reproductive-system anatomy. Branson (1962) synon- omized M. mutabilis with M. ragsdalei, apparently on the basis of external morphology, without providing sup- porting data. No comparative studies have been con- ducted involving all three species of Megapallifera.
The objectives of this investigation were: (1) to char- acterize and compare the external morphologies of each of the species of Megapallifera and (2) to compare the reproductive systems of these species in order to deter- mine species specific characters.
METHODS AND MATERIALS
Specimens of Megapallifera mutabilis were collected on 18 May 1989 at the t\pe localitv (just west of Schoolfield, Pittsylvania County, Virginia), elevation approximately 150 meters, under loose bark of dead trees. Specimens of M. wetherbyi were collected on 23 May 1987 and 16 May 1989 at the type locality (near the mouth of the Laurel River, Whitley County, Kentucky), elevation ap- proximately 245 meters, on sandstone cliffs. One speci- men of M. ragsdalei was collected on 3 April 1988 from the t\pe locality (9.5 kilometers east of Calico Rock, on State Route 56, Izard County, Arkansas), elevation ap- proximately 125 meters, under moss on a sandstone cliff. Additional specimens of M. ragsdalei. collected 25 .-^pril 1982, at Devils Den State Park, Crawford Count), .Ar- kansas (preserved in ethanol) were obtained on loan from the Field Museum of Natural History, Chicago, Illinois (FMNH 210285).
External characteristics were compared with species descriptions to ensure correct identification of all spec- imens. Mantle color, mantle pattern and foot margin color were compared among species. The live specimens were drowned in distilled water and immediately dis- sected. The reproductive svstems of the specimens dis- sected were removed and opened so that the internal structure of the atrium and penis could be described. Measurements were taken of eight reproductive struc- tures (length of penis, length of apical chamber of penis, length of penial retractor muscle, length of spermathecal duct, length of vagina, length of oviduct, length of vas deferens, and length of hermaphroditic duct). All ma- terial was preserved in 70% ethanol subsequent to dis- section. DroNMiings and dissections of the live specimens were conducted during the same time period (1-12 June) in each year to control for differences in anatomy at- tributable to phases of the life cycle.
All drawings are tracings of the systems or organs
Page 72
THE NAUTILUS, Vol. 104, No. 2
<l*.
'\^
^ts
1
2
3
Figures 1-3. Mantle patterns. 1. Megapallifera mutabilis. 2. Megapallifera wetherbyi. 3. Megapallifera ragsdalei. Scale bar equals 10 mm
Table 1 . Length comparisons of eight reproductive structures (means with ranges in parentheses) and results of anal\ sis of variance tests Measurements in millimeters
|
M. mutabilis |
M. wetherbyi |
M. ragsdalei |
|||
|
(N = 3) |
(N = 2) |
(N = 3) |
F |
P' |
|
|
Length of slug- |
60 0 |
71,5 |
,5(),(^' |
— |
— |
|
(55.0-65.0) |
(68.0-75.0) |
— |
|||
|
Penis |
11.6 |
16,7 |
13.1 |
8.22 |
0,026^ |
|
(10.7-12.6) |
(16,1-17,3) |
(11.2-15,0) |
|||
|
Apical chamber |
1.7 |
2,6 |
1.7 |
6.74 |
0.038^ |
|
(1.6-1.8) |
(2.2-3,0) |
(1.5-2.0) |
|||
|
Penial retractor |
146 |
7.8 |
8.3 |
3.00 |
0 139 |
|
(10.0-20.3) |
(6.8-8.8) |
(6.7-10.8) |
|||
|
Spermathecal duct |
10.3 |
13.2 |
10.9 |
3,11 |
0 132 |
|
(8.6-11.5) |
(11.8-14.6) |
(10.8-11.0) |
|||
|
Vagina |
1.7 |
1.6 |
1.6 |
004 |
0.966 |
|
(1.5-1.9) |
(-) |
(1.0-2.7) |
|||
|
Oviduct |
9.1 |
15.8 |
9.4 |
2.87 |
0.148 |
|
(6.8-12.6) |
(12.2-19.3) |
(6.8-11.4) |
|||
|
Vas deferens |
18.7 |
34.5 |
28.1 |
5.48 |
0.055 |
|
(15.1-32.2) |
(29.9-39.1) |
(23.5-35.2) |
|||
|
Hermaphroditic duct |
28.9 |
40.0 |
23,3 |
7.35 |
0,032^ |
|
(23,8-32.2) |
(.^4. 4-155) |
(20 8-25 5) |
' Dciir.'cs of freedom 2 and 5.
- Crawling.
^Oniy one living specimen was obtained.
* Signifii ant difference at 5% level.
H. L. Fairbanks, 1990
Page 73
Table 2. Results of the Modified Duncan Multiple Range Tests. Means (in millimeters) underscored by the same line are not significantly different at the 5% level. A, Mcgapallifera mu- tahilis. B, Megapallijera wcthcrlnji: C, Megapallifera rags- dalci.
|
Species |
.\ |
t: |
15 |
||
|
L.ength of penis Lengtii of apical chamber |
11.57 l,(i7 |
13 01 1 73 |
l(i,7() 2,60 |
||
|
Species |
C |
A |
B |
||
|
Length of hermaphroditic |
di |
ict |
23 33 |
2S93 |
39 9.) |
figured The reproductive system was traced from a spec- imen pinned out in a \va.\-bottom petri dish and pro- jected, via an overhead projector, onto 8'/2 x H paper. The atrial and penial figures are tracings of photographic slides projected onto 8'/2 x 11 paper. Voucher specimens have been deposited in the National Museum of Natural History. Smithsonian Institution (USNM S54012 for Megapallifera ragsdalei; USNM 854013 for M. weth- erbyi. L'SNM 854014 for M. mutabilis).
Analysis of variance was used to compare the means of measurements of reproducti\'e organs. After the anal- ysis of variance tests were conducted, a modified Duncan Multiple Range Test (Kramer, 1956) was used to deter- mine which means, among those compared in a given ANOX'A, were significantly different.
RESULTS
E.XTERNAL Characters
All living specimens attained crawling lengths that varied between 50 and 75 millimeters (figures 1-3). All had some transverse chevron-shaped bands on the mantle (figures 1-3). All had gray or white foot margins.
The mantle color of Megapallifera mutabilis was fawn or tan whereas the mantle color of M. ivetherbiji and M. ragsdalei was gray. The "spots" that produce the mantle pattern were light to dark brown in all three species; however, the arrangement of those spots varied among species. Both M. wetherbtji and M. ragsdalei had broad distinct chevrons in their mantle pattern (figures 2, 3). In M. mutabilis the mantle pattern was a series of spots that in some cases produced vague chevrons on the man- tle (figure 1).
Observed habitat preferences varied among the species. Megapallifera mutabilis preferred old-growth decidu- ous forest, whereas M. wetherbyi and M. ragsdalei pre- ferred areas in which sandstone outcrops and cliffs were common.
Reproductive System Characters
Comparisons of length measurements of some repro- ductive structures are shown in table 1. Analysis of vari- ance tests (table 1) indicated three significant differences
Figures 4-6. Genitalia, 4. Megapallijera wetherbyi. .5. Mcga- pallifera ragsdalei. 6. Megapallifera nuilahilis. Scale bar e(|uals 10 mm .'\C, apical chamber; ,-\G, albumen gland, (.',. gonad; HD, hermaphroditic duct; L.\, lower atrium; P, penis; PR, penial retractor; SD. spermathecal duct; I'A, upper atrium; L'V, free oviduct; V, vagina; VD, vas deferens.
among species. For each of these tests, the Modified Duncan Multiple Range Tests (table 2) indicated which of the species were significantly different from the others. All specimens had an atrium with two "parts", a lower atrium and an upper atrium (figures 7-9). The external surface of the lower atrium (lying within the body cavity) was covered with glandular material (figures 4-6), the internal surface was relatively smooth (figures 7-9). The color of the glandular material on the outside surface of the lower atrium varied among species: light orange for Megapallifera wetherbyi. white for M. ragsdalei. cream for M. mutabilis. The external surface of the upper atrium, in all specimens, was nonglandular, and had ac- cessory retractor muscles located near the origin of the vagina (figures 4-6). Internally, the upper atrium con- tained two labia-like lobes, one on either side of the opening to the penis (figures 7-9). In M. mutabilis these lobes were the least complex, having two or three folds that divided a lobe into sublobes (figure 9). In M. weth- erbtji the primary lobes had two to three folds (figure 7) whereas M. ragsdalei had four or fi\e sublobes (figure 8).
Page 74
THE NAUTLIUS, Vol. 104, No. 2
Figures 7-9. Internal details of the atria. 7. Mcgapallifera wethcrbyi. 8. Mcgapallifera ragsdaln. 9. Mcgapallifera niu- tahilis. Scale bar equals 10 mm. AL, atrial lobes; LA, lower atrium; P, penis; PO, penial opening; SD, spermathecal duct; UA, upper atrium; UV, free oviduct.
The penes of all specimens had an apical chamber at the vas-deferens end, i.e.. a part of the penis set off by an internal constriction (figures 10-12). The size of the apical chamber varied among species (table 1), but in- ternally there was little variation in the pattern of folds and pilasters among species. Internally, below the apical chamber, the penis of M. mittabilis had five to seven (justulose pilasters that began at the vas-deferens end and gradually disappeared at approximately the midpoint of the penis (figure 12). The remainder of the penis, inter- nally, was pustulose. The penis of M. ragsdalei had seven to nine pustulose pilasters that ran the entire length of the penis (figure 11). The internal penial anatomy of M. wetherbyi (figure 10) was similar to that of M. ragsdalei (figure 11). All specimens lacked a penial sheath (figures 10-12).
DISCUSSION
The external characteristics, mantle color and mantle pattern, of Mcgapallifera mutabilis were clearly differ- ent from both M. wetherbyi and M. ragsdalei (figures 1-3). In addition, the internal morphology of the penis (figures 10-12) and the shape of the upper atrial lobes (figures 7-9) of M. mutabilis were different from those
Figures 10-12. Internal detail of the penes 10. Mcgapallif- era wetherbyi. 1 1. Mcgapallifera ragsdalei. 12. Mcgapallifera mutabilis. Scale bar equals 10 mm. AC, apical chamber; PR, penial retractor; \'D, vas deferens.
of both M. wetherbyi and M. ragsdalei. Significant dif- ferences between the mean lengths of the penis and the apical chamber of the penis (table 2) were demonstrated between M. mutabilis and M. wetherbyi. These data support the species status of M. mutabilis.
External morphological data supporting the separation of Megapallifera wetherbyi from M. ragsdalei were not conclusive (figures 2, 3). However, internal morpholog- ical data supported specific-level separation of these two taxa. Mean lengths of the penis, the apical chamber of the penis, and the hermaphroditic duct for M. tvetherbyi were significantly greater than those of M. ragsdalei (table 2). In addition, the lobes in the upper atrium of the former were different from those of the latter (figures 7, 8). Hubricht (1956) mentioned a pilaster that extended from the lower vagina into the upper atrium Webb (1950) mentioned a single pilaster or a bilobed pilaster in the upper atrium. Neither author figured the lobes in the uneverted condition. This study has demonstrated that there are two separate lobes located in the upper atrium, one on either side of the opening into the penis
H. L. Fairbanks, 1990
Page 75
and below the opening into the vagina. In addition, these lobes were, in some specimens, quite complex. In these three species the most obvious reproductive-system dif- ferences were in these lobes, i.e.. all three species were easily separated on the basis of these lobes alone (figures 7-9). Webb (1951) made note of the atrial lobes during studies of the courtship between two M. wetherhiji. The lobes were referred to as "hoods", in their everted shape, and they appeared to play a significant role in premating behavior. In view of the apparent function of these lobes it seems appropriate, for these three species, to attach considerable significance to atrial lobe differences.
In summary, this study demonstrated species-specific morphological differences, both external and internal, between Megapallifera mutabilis, M. wetherbyi, and M. ragsdalei.
ACKNOWLEDGEMENTS
Thanks go to Susan McKee, who was the onlv person to find a live specimen of Megapallifera ragsdalei at the t\ pe locality. Thanks also go to Dr. Richard Reeder, who helped locate specimens used in this study, and provided valuable comments concerning the writing of this paper. Financial support for field work was provided by grants
from the Research Development Grant iMind of Penn- sylvania State University.
LITER.4TL RE CITED
Binne\, W. G. 1874. On tlie genitalia and liguai dfiititioii of Pulmonata. .Annals of the Lyceum of Natural Histor\ of New York 11:20-46, pis. 1-6.
Branson, B. A. 1962. The slugs (Gastropoda: Pulmonata) of Oklahoma and Kansas u itii new records. Transactions of the Kansas Academy of Science 65(2):110-119.
Hubricht, L. 1951. Three new land snails from eastern L^iited States. The Nautilus f55(2):57-59.
Hubricht, L. 1956. Megapalliffra. nt-w subgenus. The Nau- tilus fj9(4): 126.
Hubricht, L. 1976. Notes on some land snails of the eastern United States. The Nautilus 90(3):104-107
Kramer, C. Y. 1956. Extension of multiple range tests to group means with unequal numbers of replications. Biometrics 12:307-310.
Webb, G B 1950 New and neglected philonncids and the genus Eumclu.s Bafinesque (Mollusca. Gastropoda, Pul- monata). Transactions of the American Microscopical So- ciety 69(l):54-63.
Webb, G B 1951. Notes on the sexology of philomycid slugs of the genus Eumelus Bafinesque. Journal of the Tennessee Academy of Science 26(l):73-78.
THE NAUTLIUS 104(2):76
Page 76
Ovophagy in Anachis avara (Say, 1822) (Gastropoda: Columbellidae)
\I. G. Harasewych
Department of Invertebrate Zoology National Museum of Natural History Smithsonian Institution Washington, DC 20560, L'SA
Five strands of egg cases of Melongena corona altispira Pilsbry and X'anatta, 1934, were collected in the Indian River, near VVabasso, Indian River County, Florida in July of this year and maintained in a recirculating sea- water table together with appro.ximately fifty specimens of Melongena corona altispira. When examined after several hours in the seawater table, si.x specimens of An- achis avara (Say, 1822) were found on the egg capsules. The Anachis were removed and returned to the table approximately one meter from the egg cases. The cap- sules were examined and placed in a large bowl, the rim of which e.xtended above the water level in the seawater table by two centimeters. Seawater flowed into the bowl, overflowing the rim into the table.
The following morning (12 hours later) four of the six specimens of Anachis avara in the seawater table were again on the flat sides of the egg capsules, each on the terminal capsule of a strand. When examined under a dissecting microscope, the columhellids were observed to have penetrated the walls of the egg cases near the centers of the capsules, and to be feeding on the Melon- gena larvae and on the dense inner layer of albuminous fluid (figure 1). To reach the egg capsules, the Anachis had to crawl past two large Mercenaria mercenaria that had been cracked open and placed in the tank to feed the Melongena.
Although there was not sufficient time to repeat these observations with appropriate controls, it seems clear that Anachis avara is capable of locating gastropod egg cases at considerable distances by chemosensory means. It is unclear whether Anachis avara showed a preference for egg cases over Mercenaria mercenaria, or if it was de- terred from feeding on the bivalves by the presence of feeding Melongena.
Members of the family Columbellidae have extremely diverse and opportunistic diets that may consist of poly- chaetes, small Crustacea, a.scidians, hydroids, algae, or- ganic detritus and carrion (Hatfield, 1979; Taylor et ai, 1980). Taylor (19S7) reported that six of 16 specimens
Figure 1. .\nachi.s avara feeding on cunma altispira.
Mel,
Hungena
of Mitrella scripta examined contained gastropod eggs in their stomachs. The present observations suggest that gastropod eggs represent a significant dietar\' item for at least some species of columhellids
This is contribution number 264 of the Smithsonian Marine Station at Link Port.
LITERATURE CITED
llathekl, E 15 1979. Food sources for Anachis avara (Col- uinhellidae) and a discussion of feeding in the family. The
Nautilus 93(l):40-4.3.
Taylor, J. D. 1987. Feeding ecolog) of some corninon niter- tidal iieogastropods at Djerba. Tunisia \'ir \lillicu •')7(1): 1.3-20,
Ta\l(M, J I), \ J NU.rris. and C N. Tavlor 19S0. Food sptTi.ili/alioii and the e\'olution of predatory prosobraneh gastropods J'alaeontologN 23(2):375-409.
INSTRUCTIONS TO AUTHORS
THE NAUTILUS publishes papers on all aspects of the biology and systematics of mollusks. Manuscripts de- scribing original, unpublished research as well as review articles will be considered. Brief articles, not exceeding 1000 words, will be published as notes and do not re- quire an abstract. Notices of meetings and other items of interest to malacologists will appear in a news and notices section.
Manuscripts: Each original manuscript and accompa- nying illustrations should be submitted in triplicate. Text must be typed on one side of 8'/2 x H inch white paper, double spaced throughout (including literature cited, ta- bles and figure captions), with at least 1 inch of margin on all sides. All pages must be numbered consecutively. If printed on a word processor, the right margin should be ragged rather than justified. Authors should follow the recommendations of the Council of Biology Editors Style Manual, which is available from the Council of Biology Editors, Inc., 9650 Rockville Pike, Bethesda, MD 20814, U.S.A. The first mention of a scientific name in the text should be accompanied by the taxonomic au- thority, including year. Latin names and words to be printed in italics must be underlined; leave other indi- cations to the editor. Metric and Celsius units are to be used.
The sequence of sections should be: title page, abstract page, introduction, materials and methods, results, dis- cussion, acknowledgements, literature cited, tables, fig- ure captions, figures. The title page should include the title, author's name(s) and address(es). The abstract page should contain the title and abstract, which should sum- marize in 250 words or less the scope, main results and conclusions of the paper. The abstract may be followed by a maximum of 8 key words. All references cited in the text must appear in the literature cited section and \ice versa. In the literature cited section, all authors must be fully identified and listed alphabetically. Follow a recent issue of THE NAUTILUS for bibliographic style, noting that journal titles must be unabbreviated. Infor- mation on plates and figures should be cited only if not included in the pagination. Tables must be numbered and each placed on a separate sheet. A brief legend must accompany each table. Captions for each group of illus- trations should be typed on a separate sheet and include a key to all lettered labeling appearing in that group of illustrations.
All line drawings must be in black, high quality ink, clearly detailed and completely labeled. Photographs must be on glossy, high contrast paper. All figures are to be consecutively numbered (figs. 1, 2, 3, ... , NOT figs. la. lb, Ic, . . . NOR plate 1, fig. 1 . . .). Illustrations must be arranged in proportions that will conform with the width of a page (6% inches or 171 mm) or a column (314 inches or 82 mm). The maximum size of a printed figure is 6% by 9 inches or 171 by 228 mm. All illus- trations must be fully cropped, mounted on a firm, white backing, numbered, labeled and camera ready. The au- thor's name, paper title and figure number(s) should ap- pear on the back. Original illustrations must be between one and two times the desired final size. It is the author's responsibility that the line weight and lettering are ap- propriate for the desired reduction. Original illustrations will be returned to the author if requested. Color illus- trations can be included at extra cost to the author.
Voucher Material: Deposition of type material in a recognized public museum is a requirement for publi- cation of papers in which new species are described. Deposition of representative voucher specimens in such institutions is strongly encouraged for all other types of research papers.
Processing of Manuscripts: Upon receipt, every manu- script is acknowledged and sent for critical review by at least two referees. These reviews serve as the basis for acceptance or rejection. Accepted manuscripts are re- turned to the author for consideration of the reviewers' comments. A finalized version of the manuscript is re- turned to the editor and sent to press. Two sets of proofs are sent to the author for correction. Changes other than typesetting errors will be charged to the author at cost. One set of corrected proofs should be sent to the editor as soon as possible. Authors with institutional, grant or other research support will be billed for page charges at the rate of $60.00 per printed page.
An order form for reprints will accompany the proofs. Reprints may be ordered through the editor.
Manuscripts, corrected proofs and correspondence re- garding editorial matters should be sent to: Dr. M.G. Harasewych, Editor, Division of Mollusks, NHB stop 118, National Museum of Natural History, Smithsonian In- stitution, Washington, DC 20560, USA.
THIS PUBLICATION IS PRINTED ON ACID-FREE PAPER.
rHE NAUTILUS
Volume 104, i\ umber 3 October 11, 1990 ISSN 0028-1344
A quarterly devoted to malacology.
Marine Bi"'"^''^"^' laboralo:
OCT 19
'— '- Mole, Mass. ^
EDITOR-IN-CHIEF Dr. M G. Harasewych Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
ASSOCIATE EDITOR Dr. R. Tucker Abbott American Malacologists, Inc. P.O. Box 2255 Melbourne, PL 32902
CONSULTING EDITORS Dr. RiJdiger Bieler Department of Malacology Delaware Museum of Natural History P.O. Box 3937 Wilmington, DE 19807
Dr. Robert T. Dillon, Jr. Department of Biology College of Charleston Charleston, SC 29424
Dr. William K. Emerson
Department of Living Invertebrates
The American Museum of Natural
Historv
New York, NY 10024
Mr. Samuel L. H. Fuller 1053 Mapleton Avenue Suffield, CT 06078
Dr. Robert Hershler Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
Dr. Richard S. Houbrick Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
Mr. Richard I. Johnson Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, OH 43210
Dr. James H. McLean Department of Malacology Los Angeles County Museum of Natural History 900 Exposition Boulevard Los Angeles, CA 90007
Dr. Arthur S. Merrill % Department of Mollusks Museum of Comparative Zoology Harvard Universilv Cambridge, MA 02138
Ms. Paula M. Mikkelsen Harbor Branch Oceanographic Institution, Inc. Ft. Pierce, FL 33450
Dr. Donald R. Moore
Division of Marine Geology
and Geophysics
Rosenstiel School of Marine and
Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149
Mr. Richard E. Petit
P.O. Box 30
North Myrtle Beach, SC 29582
Dr. Edward J. Petuch Department of Geology Florida Atlantic University Boca Raton, FL 33431
Dr. David H. Stansbery Museum of Zoology The Ohio State University Columbus, OH 43210
Dr. Ruth D. Turner Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Geerat J. Vermeij Department of Geology University of California at Davis Davis, CA 95616
SUBSCRIPTION INFORMATION
The subscription rate per volume is US $25.00 for individuals, US $35.00 for institutions. Postage outside the United States is an additional US $4.00 for surface and US $12.00 for air mail. All orders should be accompanied by payment and .sent to: THE NAUTILUS, P.O. Box 3430, Silver Spring, MD 20901.
Change of address: Please inform the publisher of your new address at least 6 weeks in advance. All communications should include both old and new addresses (with zip codes) and state the effective date.
THE NAUTILUS (ISSN 0028- 1344) is published quarterly by Trophon Corporation, 8911 Alton Parkway, Silver Spring, MD 20910.
Second Class postage paid at Silver Spring, MD and additional mailing offices.
POSTMASTER: Send address changes to: THE NAUTILI'S P.O. Box 3430 Silver Spring, MD 20901
THE
AU T I L U S
CONTENTS
Volume 104, Number 3 October 11. 1990
ISSN 0028-1344
-■jjrdior;
James H. McLean
Li
A new genus and species of neomplialid limpet from the Mariana Vents w ith a review of current understanding gf relationsfiips among Neomphalacea and Peltospiracea
iU
R. Douglas Hunter
Shell dissolution rate in fresh .vater pulmonate snails: influence of periostracuni and water chemistry . .
87
Thomas Stahl David M. Lodge
Effect of experimentally induced shell damage on mortality, reproduction and growth in Helisoma trivolvis (Say, 1816)
92
Edward J. Petuch
New gastropods from the Bermont Formation (Middle Pleistocene) of the Everglades Basin
96
B. A. Marshall
Micropilina tangaroa, a new monoplacophoran (Mollusca) from northern New Zealand
105
William K. Emerson Walter E. Sage, III
Addenda to "Distorsio ridens (Reeve, 1844); A synonym of Distorsio clathrata (Lamarck, 1816) (Gastropoda: Personidae)"
108
THE NAUTILI'S 104(3):77-86, 1990
Page
A New Genus and Species of Neomphalid Limpet from the Mariana Vents with a Review of Current Understanding of Relationships among Neomphalacea and Peltospiracea
James H. McLean
Lui Angeles Count) Museum of
Natural History 900 Exposition Boulevard Los Angeles, CA 90007, USA
ABSTRACT
Symmetromphalus regularis new genus, new species, is de- scribed from Intlrothermal vents of the Mariana Back Arc Basin. It differs from Seornphalufi jretterae McLean, f9SI, in having; the opening of the mantle cavity directed anteriorK rather than to the left, more numerous epipodial tentacles, the operculum retained in the adult, and in a deep sperm groove on the left cephalic tentacles of males.
The famil) Cyathermiidae is here proposed for two coiled members of the superfamiK Neomphalacea, the genera Cya- thermia and Lacunoides. both of VVaren and Bouchet (1989), The family Cyathermiidae is characterized by: a short snout, a closed sperm groove along the left cephalic tentacle, and two cirri at the tip of the left cephalic tentacle
Neomphalacea can be associated with Peltospiracea in a sub- order Neomphalina, on the basis of shared characters (non- nacreous shell, monotocardian heart, bipectinate gill, lack of ctenidial bursicles, similar radula). As these may be plesio- morphic or convergent characters, further anatomical com- parisons are needed to establish additional synapomorphic char- acters for such a suborder .\ fossil record of the newly expanded complex is yet elusive, but should continue to be sought.
Key words: .\rchaeogastropoda; Neomphalacea; Symmetrom- phalus, Cyathermiidae; Peltospiracea; hydrothermal-vent lim- pets; Mariana Vents.
INTRODUCTION
Neomphalus fretterae McLean, 1981, the largest and most densely aggregated of hvdrothermal-vent limpets, was the first vent-limpet to be described (McLean, 1981). Its anatomy was treated in an accompanying paper by Freneret al. (1981). Although I expected that additional species of Seomphalus would eventually be found at other sites, none were found until the fauna of the Mar- iana Back .\rc Basin was sampled in 1987, at which time a new, monotypic genus in the family Neomphalidae was discovered. The primary objective of this paper is to provide the formal description of the new genus and species Symmetromphalus regularis.
Recently, an affinity with Neomphalus w as recognized in two coiled genera described by Waren and Bouchet (1989) from Eastern Pacific hydrothermal vents: Cya- thermia and Lacunoides. These small-shelled, monotyp- ic genera are regularly coiled and have many of the diagnostic features common to Neomphalus. although they share other unique features, which indicate that they in turn should be segregated within their own fam- ily. Accordingly, the family Cyathermiidae is here pro- posed.
Higher classification of Neomphalacea and the re- cently proposed and probably related Peltospiracea Mc- Lean ( 1 989a) has been discussed by Haszprunar ( 1 988a,b, 1989), Waren and Bouchet (1989), and Fretter (1989). Another objective of this paper is to briefly review the current work that assesses these relationships, noting the gaps in our understanding of anatomy in certain mem- bers.
My early interpretation of the possible fossil affinity of Neomphalus has generated some controversy ; here I take the opportunity to review these criticisms and offer a revised assessment of the potential for a fossil record of the groups treated here.
MATERIALS AND METHODS
The new species described here was first collected w ith the deep-submersible Alvin in May, 1987, at hydrother- mal vents of the mid-Pacific Mariana Back .^rc Basin. A general description of the site was given b\ Hessler et al. (1988). Until now, two other gastropods, Alvinocon- cha hessleri Okutani and Ohta, 1988, and Pseudorimula marianae McLean, 1989b, have been described from these vents.
Limpet specimens were collected w itli the mechanical arm of the Alvin in the course of collecting substrate samples and general collecting of all organisms. Material was preserved upon reaching the surface and was orig- inally fixed for 24 hours in lO^c seawater formalin buf- fered with sodium borate, washed in fresh water, and transferred to 70% ethanol (for details of collecting pro-
Page 78
THE NAUTILUS, Vol. 104, No, 3
cedures see Turner et ai, 1985). Preserved specimens were sorted at Scripps Institution of Oceanography and forwarded to me by Robert R. Hessler.
Radulae were extracted from preserved specimens af- ter dissolution of tissues with 10% NaOH for 48 hours, air dried and coated with gold palladium for SEM ex- amination. Juvenile shells with protoconchs were ex- amined with SEM. Protoconch lengths were taken di- rectly from scale indications for the SEM micrographs.
Repositories of the t\pe material are the Los Angeles County Museum of Natural History (LACM), the United States National Museum (USNM), and the Museum Na- tional d'Histoire Naturelle, Paris. All figured specimens are deposited at the LACM.
phalic lappets. Eyes lacking, epipodial and cephalic ten- tacles non-papillate, left cephalic tentacle of male mod- ified to function as penis, sperm groove open or closed. Gonad with glandular gonoducts, dorsal to digestive gland and intestine; females with seminal vesicle.
Radula rhipidoglossate, cusps of all teeth aligned in descending rows, shaft lengths of all teeth increasing toward edge of ribbon. Rachidian tooth with shaft broad at base and acutely pointed overhanging cusp. Lateral teeth four pairs, inner surfaces excavated to articulate with rachidian or adjacent lateral teeth, overhanging cusps of laterals like those of rachidian tooth. Marginal teeth numerous, shafts wide but incompletely separated at base, tips deeply serrate.
SYSTEMATICS
Superorder ARCHAEOGASTROPODA Thiele, 1925
Recent authors (Salvini-Plawen, 1980; Salvini-Plawen & Haszprunar, 1987; Haszprunar, 1988a, b; Hickman, 1988) have discussed the problems inherent in the "archaeo- gastropod" concept, pointing out that Archaeogastrop- oda, as traditionally constituted (Thiele, 1925; Knight et ai, 1960) represents a grade.
Hickman (1988) redefined Archaeogastropoda to in- clude superfamilies Pleurotomariacea, Fissurellacea, and Trochacea, stating that it was thereby synonymous with Haszprunar's concept of Vetigastropoda Salvini-Plawen, 1980. However, Haszprunar (1988a, b) also included Le- petodrilacea McLean, 1988, in Vetigastropoda, which inclusion was overlooked by Hickman (1988) and also by Bieler (1990:380) in hiscritic}ueof Haszprunar's work. I follow Haszprunar ( 1988a, b) in retaining the traditional meaning of Archaeogastropoda, allowing it to be ex- pressly indicated in a classification as an orthophyletic grade.
Superfamily NEOMPHALACEA McLean, 1981
The diagnosis that follows encompasses two families, the Neomphalidae and the Cyathermiidae new family, tak- ing into account the characters of the two coiled genera described by Waren and Bouchet (1989). It will, how- ever, need to be modified once the internal anatomy of all genera becomes known.
Diagnosis: Shell regularly coiled or of limpet form, lack- ing nacre, periostracum thick; first telcoconch whorl with oblique aperture and rounded whorls, regularly coiled in all genera; protoconch with net-pattern surface sculp- ture; opercuhnn multispiral initially, final volution en- larged, retained at least through the first telcoconch whorl in all members
Monotocardi^Hi. ventricle not penetrated by rectum; left kidney only. tJtenidiurn bipectinate, afferent mem- brane lacking or ver\ short, gill axis producing sturdy free tip, filaments elongate, skeleton lacking bursides. Perioral surface with transverse furrow extending to ce-
CYATHERMIIDAE new family
Diagnosis: Shell coiled through teleoconch; sculpture smooth to finely reticulate. Neck short; short snout pres- ent; cephalic tentacles anterio-lateralK directed; en- larged left tentacle serving as penis, sperm groove of enlarged left tentacle closed, tip with two prominent cirri. Afferent ctenidial membrane ver\ short. Cusps of rachidian and lateral teeth finely serrate, cusp of ra- chidian tooth much longer than those of inner lateral teeth.
Included genera: Cyathermia Waren and Bouchet, 1989, and Lacunoides Waren and Bouchet, 1989. Cyathermia is monotypic for C. naticoides Waren and Bouchet, which is widely distributed on the East Pacific Rise. Lacunoides is monotypic for L. exqiiisitus Waren and Bouchet, known only from the Galapagos Rift.
Remarks: Separation of the two monotypic coiled gen- era from the two monotypic limpet genera is now ap- propriate at the familial level, given that each of the two groups of genera have synapomorphic characters in com- mon. Diagnostic characters of the Cyathermiidae are the short snout, left cephalic tentacle with closed sperm groove and two cirri at the tip, serration of rachidian and lateral teeth and enlargement of rachidian tooth. See Waren and Bouchet (1989) for more detailed descriptions of these two genera.
Family NEOMPHALIDAE McLean, 1981
Diagnosis: Shell coiled through first teleoconch whorl, changing to limpet form in second teleoconch whorl; sculpture of strong radial ribs. Neck long; snout lacking in adult; cephalic tentacles posteriorly directed; sperm groove of enlarged left tentacle open; cirri at tip of penis lacking. Cusps of rachidian and lateral teeth non-serrate, cusp of rachidian tooth of same length as those of inner lateral teeth.
Included genera: Meornplialiis McLean, 1981, and Symmetromphalus new genus, Neomphalus is mono- typic for N, fretterae McLean. 1981, known from the Galapagos Rift (the type locality) and from sites on the East Pacific Rise. Syinmetroniphalus is monotypic for S.
J. H. McLean. 1990
Page 79
regtdaris new species, known onl\ from the Mariana Back Arc Basin vents.
Remarks: Diagnostic characters of the Neomphahdae are the limpet form of the mature shell, absence of snout, posterior direction of cephalic tentacles, open sperm groove and lack of cirri on the enlarged left tentacle. See Fretter et al. (1981) for a more detailed description of anatomy in Neomphalus fretterae.
Symmetromphalus new genus
Type species: Sijmmetromphalus regularis new species.
Description: Shell of limpet form, mantle cavity and horseshoe-shaped muscle open anteriorly; shell outline symmetrical in juvenile, irregular in mature specimens; coiled apical whorl offset to right. Sculpture of finely beaded radial ribs; operculum present in adult. Neck long, perioral surface with transverse furrows extending to cephalic lappets. Cephalic tentacles short, posteriorly directed, left tentacle of male greatK distended, deep dorsal sperm groove connecting with groove on left side of neck. Epipodial tentacles present posteriorly and lat- erally. Gill bipectinate, afferent membrane lacking, fil- aments elongate, efferent axis of free tip extended over long neck. Radula rhipidoglossate, four pairs of lateral teeth, cusps similar to those of rachidian teeth, except fourth lateral teeth strongK' serrate on outer edge; mar- ginal teeth numerous.
Remarks: On characters of external anatomy, Sym- metromphalus differs from Neomphalus in its: anterior rattier than leftward opening of the mantle ca\it> and shell muscle, its evenly distributed rather than posteriorly grouped epipodial tentacles, smaller cephalic tentacles, greater prominence of sperm groove in enlarged left cephalic tentacle, and apparent absence of well-defined food groove. The shell differs in ha\ing strong beading on early ribs and lacking the interior ridge. A vestigial operculum is present in mature specimens. The radula is similar in both genera.
Most of these distinctions are regarded as significant at the generic level. Only the sculptural difference (prominent beading rather than smooth ribs) is consid- ered a species-level difference by itself.
Names of both the new genus and species emphasize the regular and symmetrical aspect, in contrast to the leftward shift of the mantle cavit\ that characterizes Seomphalus.
Symmetromphalus regularis new species (figures 1-17)
Description: Shell (figures 1-3, 7-10, 17) of medium size for family (maximum length 14.0 mm for females, 10.6 mm for males), white under thick, pale tan perios- tracum, which projects beyond edge of shell. Profile mod- eratel) elevated; juvenile shell nearly symmetrical, out- line of mature shell irregular, indicating habitual site of
attachment. Apical whorl markedK posterior in juvenile shell (figures 11, 12), closer to center in mature shell. I'rotoconch (figures 13. 14) length 220 ^^\, surface sculp- ture of irregular network of low ridges. First teleoconch whorl rounded, suture deep, coiled through one-half whorl of growth. Limpet form attained after completion of first teleoconch whorl; growth of posterior slope beginning at shell length of 1.5 mm. Radial (spiral) sculpture arising at shell length of 1 mm, consisting of low primary cords on which beading appears at shell length of 2 mm. Sec- ondary cords arise at shell length of about 7 mm. quickly assuming size of primary cords; cords at margin very narrow, retaining beading, interspaces broad. Shell in- terior glossy white. Muscle scar horseshoe-shaped, open anteriorly, broad throughout, except posteriori}-; anterior terminations rounded. Apical pit remaining open.
Dimension of holotype (female): Length 12.3, width 10.1. height 5.0 mm; dimensions of illustrated paratype (male); length 8.4, width 6.5, height 3.0 mm.
External anatomy (figures 4-7, 9): Neck long, wide, dorso-ventrally compressed, lateral edges acutely angu- late (except left edge deeply grooved in male). Trans- verse furrow extending laterally above mouth, delimiting the ventrally positioned oral lappets. E\'es lacking, ce- phalic tentacles posteriorly directed, equal and relatively short and thin in females (contracted state); left tentacle of male enormously distended, bearing a deep sperm groove dorsally, which is continuous with deep groove on left edge of neck. Females lack groo\e on left edge of neck.
Mantle cavity deep, extending two-thirds the length of shell muscle on left side. Ctenidium bipectinate, af- ferent membrane lacking throughout its length, efferent axis arising at posterior of mantle ca\ it\ on left; free tip of gill separating above base of neck, its efferent axis massive, extending well anterior of head; gill filaments overlying head, greatly elongate, decreasing in length toward tip.
Mantle margin with fine papillae corresponding to radial ribs. Outline of foot rounded; anterior edge of foot with furrow marking opening of pedal gland. Epipodial ridge encircling foot, extending forw ard on both sides to join with neck edges; short, contracted epipodial ten- tacles evenly spaced along ridge, becoming smaller an- teriorly, not extending anteriorly beyond position of shell muscle. Operculum (figure 9) ver>- thin, transparent, multispiral, with rapidK enlarging final whorl, edge frayed, shed in some large females (largest operculum about 4 mm diameter).
In dorsal view of detached animal, shell muscle arms very broad, except posteriorly, where reaching one-fifth the maximum width: anterior terminations rounded; mantle skirt thin, show ing posteriormost extent and out- line of ctenidium; pericardium \ isible as dark structure posterior to gill; gonad and pallial gonoducts large, over- King digesti\e gland, occupying posterior dorsal area next to right arm of shell muscle (figure 4).
Radula (figures 15, 16) rhipidoglossate, rachidian and
Page 80
THE NAUTILUS, Vol. 104, No. 3
Figures 1-10. Synunetjomphalus regulari, new species, trom .\lice Springs vents, Mariana Back Arc Basin, Alvin dive 184,3, 3,640 m. Anterior at top in dorsal and ventral views. 1-6. Holotype (female), LACM 2432, shell length 12.3 mm. 1 Shell e.xtenor_ 2. Shell interior 3. Left side of shell. 4. Dorsal view of detached bod> .5. Ventral view of detached body. 6. Left la era view ot detached body. 7-!0. Paratype (male), LACM 2433, shell length 8 4 mm. 7. Dorsal view of detached body. 8. Shell exterior. 9. Ventral view, animal attached to shell, showing opercuhim on edge. 10. Left side of shell.
four pairs of lateral teeth of similar morphology, mar- ginal teeth numerous, cusj-. rows of all teeth forming circular arc. Base of rachidian tooth broad, overhanging cusp moderately long, tapered to acute tip. First lateral
tooth slightly less prominent than rachidian tooth, inner base behind' that of rachidian tooth. Second, third and fourth lateral teeth similar to each other, their innermost bases behind the base of adjacent lateral teeth; lengths
]. H. McLean, 1990
Page 81
Figures 11-14. 1 1. Dorsal view = 100 fim.
Symmetromphalus regularis new species. SEM views of ju\enile paratvpe, LACM 2433. shell length 3.5 mm. 12. Oblique, left lateral view. 13. Protoconch and early sculpture, scale bar = 200 tim. 14. Protoconch, scale bar
of shafts and overhanging cusps increasing in length out- wardly. Fourth lateral tooth larger than third, its outer edge sharply serrate, its lowermost serration most prom- inent. Inner marginal teeth with long, broad shafts, cusp edges deepK serrate; shafts of outer marginal teeth in- completely separated.
Type locality: Alice Springs vents, Mariana Back-Arc Basin (18°12.6'N, 144°42.4'E), 3,640 m. The limpets oc- cur in dense aggregations on the walls of the vents (figure 17). From the photograph it is evident that the limpets are oriented randomly, filling all space on the substrate, but not stacked.
Type material: 27 specimens from t\pe localitv, Alvin dive 1843, 4 May 1987. Holotype LACM 2432, io para- types LACM 2433, 10 paratypes USN'M 784763, 6 para- types MNHN. All specimens have undamaged perios-
traca, free of biogenic or mineral encrustations. Males are represented by six specimens only, of which the smallest (with broken shell) is approximate!) .5 mm in length. Twelve specimens under 5 mm in length are too small to sex w ithout sectioning.
DISCUSSION
Higher Classification
The affinities and the higher classification of the N'eom- phalacea are yet to be fully resolved and are likely to remain controversial for .some time. Fretter et al. (1981) aflirined that Seoniphalus is a highly derived archaeo- gastropod, but could not relate it to other known living groups. Waren and Bouchet (1989) placed the newK' described family Peltospiridae McLean, 1989, in the
Page 82
THE NAUTILUS, Vol. 104, No. 3
Figures 15, 16. Symnictroiuphdhis rcgiiluns iitn\ species. .SEN! views of radula of paratype. 15. Full width of ribbon, showing rachidian, four pairs of lateral teeth and numerous marginal teeth, scale bar = 40 nm. 16. Enlarged view of overhanging cusps of rachidiaii, laterals and marginals, scale bar = 20 nm.
Neomphaiacea, whereas McLean {1989a), Fretter (1989), and Haszprunar ( 1988a, b, as hot- vent group A) separated two superfamilies: Neomphaiacea and Peltospiracea. Shared characters of both superfamilies include the mo- notocardian heart, bipectinate ctenidia that lack bursi- cles, oesophageal features, statocysts with statoliths, and radular similarity. In having the left kidney only and in lacking ctenidial bursicles both groups were placed out- side the \'etigastropoda (superfamilies Scissurellacea, Pleurotomariacea, Fissurellacea, Haliotacea, Trochacea,
and Lepetodrilacea) by Salvini-Plawen and Haszprunar (1987) and by Haszprunar (1988a, b). Both groups were regarded as generally more primitive than the Vetigas- tropoda by Haszprunar.
The main argument for separation of Neomphaiacea and Peltospiracea concerns the striking differences in external features that are related to feeding modes: in Neomphaiacea the neck is long and dorso-ventrally com- pressed; transverse furrows lead from the recessed mouth to protruding lappets that are ventral to the cephalic
Figure 17. Symmcdomplmlus ref^ularis new species. In situ view of limpets on basalt boulders in path of effluent at Alice Springs, Mariana Back Arc Basin, 3,640 m. The largest limpets may exceed 14 mm in length Photo courtesy S Ohta
J. H. McLean, 1990
Page 83
tentacles (see Waren & Bouchet, 1989: fig. 23 for Cya- thermia), and there is a notch for dorsal access to the mouth from the food groove (well-developed only in Neomphalus), the bipectinate gill is h\pertrophied, the gill filaments elongate and separated for filter feeding in combination with grazing. In contrast, the Peltospiracea are known by the descriptive appellation of "tapersnouts,' which was first used by McLean (1985) prior to their formal description, because of their long, tapered snouts. The tapered snout was correlated by Fretter (1989) with a well-developed, protrusible subradular organ, enabling the snout to project at great length.
The Peltospiridae include both limpet-shaped and coiled members. Two important papers on anatomy of peltospirids have been published, that of Fretter (1989) on anatomy of the limpets and the subsequent paper of Haszprunar (1989) on the anatom\ of the coiled Melano- drymia. UnfortunateK Haszprunar did not have benefit of access to the manuscript of Fretter (1989), so that comparisons could not be made. Melanodrymia is atyp- ical of peltospirids in several respects: having both the left and right tentacles modified for copulation (unlike the peltospirid limpets or other coiled peltospirids), and lacking skeletal rods in the ctenidium. It may be that Melanodrymia is not a true peltospirid, although Hasz- prunar elected not to establish a family for it.
Anatomical comparisons between all supposed pelto- spirids are needed. The limpet Hirtopelta McLean, 1989a, lacks a tapered snout and represents a genus not strictly peltospirid. Another unresolved problem has been noted: there are two different protoconch tvpes (net sculpture and longitudinallv ribbed) both in limpet genera and coiled genera (McLean, 1989a; Waren & Bouchet, 1989).
Knowledge of the internal anatomv' of Cyathermia is also needed. Because it is regularly coiled, it seems ev- ident that Cyathermia is less derived and probably a better representation of neomphalacean anatomy than Neomphalus, although the Cyathermiidae seem to have more complex reproductive modifications in having cirri at the tip of the copulatory appendage. Symmetrom- phalus. the new genus described here, is less derived than Seomphalus. for the reason that its symmetry is typical of all other prosobranch limpets, its torsion not carried through an additional 90 to place its mantle cav- ity on the left, as in Seomphalus. S'eomphalus is also more derived in having a well-defined food groove and a gill that is larger and thereby more effective than that of Symmetromphalus.
Radular similarities between Neomphalacea and Pel- tospiracea need not inilicate close affinity. Hickman (1983) first discussed both radular types, and in 1984 reported that the radula of Melanodrymia yvas similar to that of Neomphalus and that both could represent an "unspe- cialized grade of rhipidoglossate radular evolution" Haszprunar (1989) agreed that radular similarities could be '"plesioniorphic and should not be overemphasized in tracing phylogenetic relationships. ' A similar case of rad- ular uniformity is known in the earliest ontogenetic stages of most trochaceans (Waren, 1990).
One can unite the superfamilies Neomphalacea and Peltospiracea within a suborder Neomphalina based on such shared characters as the similarity of the unspe- cialized radulae, lack of nacre, and lack of ctenidial bursicles, but these are plesioniorphic, grade defining characters. It is difficult to identify apomorphic char- acters to define such a suborder. We are left yvith negative characters that suffice to remove both superfamilies from other y\ ell-defined suborders. In spite of the present dif- ficulties in justifying a suborder Neomphalina within a rigorous cladistic frameyvork, I expect that the original hy pothesis of Waren and Bouchet (common ancestry for Neomphalidae and Peltospiridae) will eventually be ac- cepted.
An alternative view of the affinity of Neomphalus was given by Sitnikova and Starobogatov (1983), in a short, unillustrated paper in which they- placed Neomphalus in their neyv suborder "Neomphaloidei" [sic] in the order N'ivipariformes Sitnikova and Starobogatov, 1982. A translation of the original Russian has been obtained, courtesy David R. Lindberg. The radula of Neomphalus was said to lack a lateromarginal plate and to have mar- ginal teeth that are not distributed in groups of small secondary teeth as in rhipidoglossate radulae of trochid, turbinid, and neritid species. Marginal teeth of Neom- phalus yvere said to be more similar to the marginal teeth in the architaenioglossate radula, particularly the genus Leonia in Pomatiidae, despite the fact that there are only tyvo pairs of marginal teeth in Leonia. Other shared characters cited yvere elongate mantle cavities and looped pallial gonoducts.
Waren and Bouchet ( 1989) dismissed the Sitnikova and Starobogatov phylogeny of Neomphalus as not to be taken seriousl) in the absence of detailed evidence, and objected to the placement of Neomphalus among the Mesogastropoda. I agree that a more convincing expo- sition of the theory needs to be presented. The radular argument seems irrelevant to me: why should the neom- phalacean radula be structured like that of other knoyvn rhipidoglossate groups? Nothing is said to falsify- the in- terpretation that it is a relatively unspecialized rhipi- doglossate radula. Recently, Golikov and Starobogatov (1988) introduced 36 new prosobranch suborders while maintaining the order Vivipariformes yvith suborders Neomphaloidei, Viviparoidei, and N'alvatoidei. This was done yvithout knoyvledge of the later introduction of Pel- tospiracea (McLean, 1989a; Waren & Bouchet, 1989; Fretter, 1989) and of recent work on Valvatidae (Rath, 1988), yvhich resulted in the placement of N'alvatacea in the subclass Heterobranchia by Ponder and \\'aren (1988).
An article in Japanese entitled "Neyv archaeogastropod superfamily Neomphalacea" by Nakamura (1986) is not to be taken as a proposal of a homonym for the super- family ; rather it is evidently a review note intended for Japanese readers.
Feeding Biology
Haszprunar (1988b) suggested that "Neomphalus itself probably does not feed by filter-feeding alone, but pos-
Page 84
THE NAUTILUS, Vol. 104, No. 3
sibly by symbiotic chemoautotrophic bacteria and/or by grazing bacterial films like some other molluscs of the hydrothermal vents. This is indicated bv its radula, which is not like those of typical Biter feeders. ..." Original reports on Neomphaltts of McLean (1981) and Fretter et al. (1981) made it clear that part of its nutrition is deri\ed from grazing, particularly in the younger stages. Symbiotic chemoautotrophic bacteria are associated with most bivalves in the hydrothermal-vent community, but the onl\ \ent-associated gastropod for which this rela- tionship is known is Alvinoconcha hessleri, as reported by Stein et al. (1988). Stein (personal communication) has informed me that other vent limpets have been sub- jected to biochemical assay (ribulose-l,5-diphosphate carbo.xylase) for chemoautotrophic s\nibionts, but the negative results were not published. There is, however, a report by de Burgh and Singla (1984) of bacterial colonization of the gill surface and direct endocytosis of the bacteria in the limpet subsecjuently described as Le- petodrilus jncensis McLean, 1988.
Haszprunar's comment that the radula of Neomphalus is not like that of typical filter-feeders is not relevant, because the radulae of filter feeding gastropods in such superfamilies as Trochacea, Cerithiacea, and Calyptrae- acea are subject to the phylogenetic constraints of the radular plans typical of each group. A typical filter- feeding radula can therefore not be defined. The radula of a filter-feeding gastropod functions primarily to rake in a food string, for which many possible morphologies are suitable.
Fossil Record
A direct fossil record for any neomphalacean or pelto- spiricean shell morphology remains to be established. In my earlier assessment of Neomphalus (McLean, 1981), I suggested that there may be a link between Neompha- lacea and the Paleozoic Euomphalacea, which I had (somewhat rashly) emphasized by placing both in a therein proposed suborder Euomphalina. The thrust of my argument was as follow s: given that euomphalaceans have been regarded as immobile and therefore potential filter-feeders (references in McLean, 1981), a gill like that of Neomphalacea could have provided the mech- anism by which filter-feeding was possible in Paleozoic euomphalaceans.
Although most subsequent authors have ignored my functional argument, Runnegar (1983) took notice of it. He did "not wish to disagree with an\ of this," but had difficulty with the resulting classificatit)n. Batten (1984) found no similarities in shell structure between Neom- phalacea and Paleozoic Euomphalacea. Bandel (1988) removed from Euomphalacea all Mesozoic genera men- tioned by McLean (1981) as possible links between the two groups. While the latter two authors have found no e^ idence supporting the connection, it can still be argued that a connection to Paleozoic euomphalaceans (or pos- sible related iiroups) through unknown intermediate steps remains possible. Now that Cyathermia, as well as the
entire peltospiracean complex, is known, it may be easier to conceive of a connection leading to other li\ing genera.
Sitnikova and Starobogatov (1983) stated that a con- nection between Neon^phalus and eumphalaceans was falsified because Euomphalacea had paired gills (on the basis of the spiral keel in some euomphalacean genera), but that rather dogmatic assumption is not generally accepted and to me seems poorly founded and unlikely. The shell of Ctjathermia has a deep sinus in the outer lip (see Waren & Bouchet, 1989: figs. 6, 7), which is undoubtedly related to projection of the single bipecti- nate gill. This evidence suggests to me that a hypertro- phied single gill like that of Neomphalacea would better correlate with spiral keels or sinuses in the lips of euom- phalaceans (see McLean, 1981; fig. 13) than would paired gills.
The coiled genera Cyathermia and Lacunoides dem- onstrate that the typical neomphalacean gill and mouth w ith dorsal access to ctenidial filaments can function in mature, coiled snails. These coiled snails are mobile, but they are also smaller, of a size comparable to the juveniles of Neomphalus and Symmetromphalus. We have yet to discover a larger, coiled member of the Neomphalacea, but there is no reason to assume that it could not function as a sedimentary filter feeder. However, we are not likely to find such a member of Neomphalacea in the h\dro- thermal-vent habitat, as it would be more prone to shell crushing by the brachyuran predators in the hydrother- mal environment.
Now that we have recognized major radiations com- prising the superfamilies Neomphalacea and Peltospi- racea, as well as the Lepetodrilacea (see McLean, 1988; Fretter, 1988), which superfamily is not discussed here, I continue to believe it likeK that these groups must have had a fossil record in the Paleozoic and early Mesozoic, the time at which all living archaeogastropod superfam- ilies diverged (more detailed discussion in McLean, 1981, 1985, 1988, 1989a, b). There are numerous extinct gas- tropod clades of the Paleozoic and Mesozoic, which are assumed to have been rhipidoglossate archaeogastropods, for which the anatomical plan remains conjectural (see Knight et al., 1960). The enormously plastic Peltospi- racea and the newly expanded Neomphalacea have only been introduced into the literature for slightly over one year, hardly enough time for paleontologists with inter- ests in Paleozoic and Mesozoic faunas to have searched for connecting links.
BlOGEOGRAPHlC IMPLICATIONS
The Mariana Back Arc Basin vents are isolated from all other known Indrothermal sites, \et the\- contain some launal elements in common with those of other sites, in addition to faimal elements found nowhere else. Only one moUusk, the lepetodrilacean limpet Lepetodritus ele- vatus McLean, 1988, occurs widely at vents on the Ga- lapagos Rift and at all Indrothermal vent-fields on the East Pacific Rise as well as at the Mariana vents (McLean, unpublished). There is also a faunal connection of the
J. H. McLean, 1990
Page 85
Mariana vents to the vents of the Mid-Atlantic Ridge: Pseitdorinmla McLean, 1989, has an undescribed con- gener at the Mid-Atlantic Ridge (McLean, in prepara- tion). Hessler et al. (1988) suggested that hvdrothermal vents associated with past spreading centers are likeK to account for these wideK disjunct distributions. Tuiuii- cliffe (1989) discussed the vicariant events that shaped the present distributions of hydrothermal-vent faunas shared b\ the East Pacific Rise and the Juan de Fuca/ Gorda Ridge S)Stems. The \icariant events that would allow interchange between the eastern Pacific ridge s\s- tems and the Mariana Back Arc Basin remain to be treated in the literature. Vast amounts of geologic time must surely be involved, in view of the slow, step-by- step dispersal of vent archaeogastropods that is necessi- tated by their lack of planktotrophic dispersal stages (for review see Lutz, 1988).
ACKNOWLEDGEMENTS
Specimens of Symmetromphalus regularis were for- warded by Robert Hessler of Scripps Institution of Oceanography. I thank Clif Coney (LACM) for oper- ating the SEM at the Center for Electron Microscopy and Microanalysis, Universit) of Southern California. Pictures of the preserved specimens are the work of Bertram C. Draper, LACM volunteer. I thank S. Ohta for the use of figure 17. Helpful commentary on the manuscript was provided by Gerhard Haszprunar and Anders Waren and by an anon\mous reviewer. I take full responsibility for the opinions expressed here and the decisions as to the need for the new supraspecific taxa.
LITERATURE CITED
Bandel, K. 1988, Reprasentieren die Euoniphaioidea eine naturlich Einheit der Gastropoden? Mitteilungen des Geo- logische-Palaontologischen Institutes der Universitat Hamburg 67:1-33.
Batten, R. L. 1984. Shell structure of the Galapagos rift limpet Neomphalus fretterae McLean, 1981, with notes on mus- cle scars and insertions. American Museum Novitates no. 2776:1-13.
Bieler, R. 1990. Haszprunar s "dado-evolutionary" classifi- cation of the Gastropoda — a critique Malacologia 31(2): 371-380.
de Burgh, M. E. and C. L. Singla. 1984. Bacterial colonization and endocytosis on the gill of a new limpet species from a hydrothermal vent. Marine Biology 84:1-6
Fretter, \'. 1988. New archaeogastropod limpets from hv- drothermal vents, superfamiK Lepetodrilacea. Fart 2. .Anatomy Philosophical Transactions of the Royal Society of London, series B, 319:33-82.
Fretter, \', 1989. The anatonn of some new archaeogastropod limpets (superfamily Peltospiracea) from hydrothermal vents. Journal of Zoolog), London 218:123-169.
Fretter, V., A. Graham, and J H, McLean. 1981. The anat- omy of the Galapagos Rift limpet, Neomphalus fretterae. Malacologia 21(l-2);:337-.361.
(;(>liko\. A, .\. atid V 1. Slarohogatov. 1988. Problems of pin logeii) and system of the prosobranchiate gastropods. In: Starobogatov, V. I. (ed). Ssstematics and fauna of Gastropoda, Bivalvia and Cephalopoda. USSR .\cademy of Sciences, Proceedings of the Zoological Institute 187:4- 77 [In Russian],
Haszprunar, G, 1988a. A preliminar\ ph\logenetic analysis of the streptoneurous gastropods. In: Ponder, W. F. (ed.). Prosobranch ph\ logeny, proceedings of a s> mposium held at the 9th International Malacologicai Congress, Edin- burgh. 1986. .Malacologicai Review, Supplement 4:7-16.
Haszprunar, G 1988h. On the origin and evolution of major gastropod groups, with special reference to the Strepto- neura. Journal of Molluscan Studies 54(4):367-441.
Haszprunar, G. 1989. The anatomy of Melanodrymia au- rantiaca Hickman, a coiled archaeogastropod from the East Pacific hvdrothermal vents (Mollusca. Gastropoda). Acta Zoologica, Stockholm 70(3): 175-186,
Hessler, R,, P, Lonsdale, and J. Hawkins, 1988, Patterns on the ocean Door, New Scientist 1 17( 160.5):47-51.
Hickman, C. S. 1983 Radular patterns, s\stematics, diversits , and ecology of deep-sea limpets. The Veliger 26(2):73-92.
Hickman, C. S. 1984. A new archaeogastropod (Rhipido- glossa: Trochacea) from hydrothermal vents on the East Pacific Rise. Zoologica Scripta 13(3):19-2.5.
Hickman, C. S. 1988 .\rchaeogastropod evolution, phylogen\ and systematics: a re-evaluation. In: Ponder. W, F, (ed.). Prosobranch ph\ logeny, proceedings of a s\ mposium held at the 9th International Malacologicai Congress, Edin- burgh, 1986. Malacologicai Review, Supplement 4:17-34.
Knight, J. B., L. R. Cox, A. M. Keen, R. L. Batten, E. L. Yochelson, and R. Robertson. 1960. Systematic descrip- tions (Archaeogastropoda). In: Moore, R. C. (ed.). Treatise on invertebrate paleontology, Part I, Mollusca 1. Geolog- ical Society of America and Universitv of Kansas Press, p. 169-310.
Lutz, R. .\. 1988, Dispersal of organisms at h\drothermal vents: a review , Oceanologica .Acta, special volume 8:23- 29.
McLean, J. H. 1981. The Galapagos Rift limpet .Womp/ia/us: relevance to understanding the evolution of a major Pa- leozoic-Mesozoic radiation. Malacologia 21:291-336.
McLean, J, H, 1985. Preliminary report on the limpets at hydrothermal vents. In: Jones, M. L. (ed.). The hydro- thermal vents of the eastern Pacific: an overview. Bulletin of the Biological Societv of Washington, no, 6:159-166,
McLean, J, H, 1986 The trochid genui Lindaria Dall, 1909: a filter feeder? American Malacologicai Bulletin 4:109
McLean, J. H, 1988, New archaeogastropod limpets from hydrothermal vents: new superfamily Lepetodrilacea, 1, Systematic descriptions. Philosophical Transactions of the Royal Society of London, series B, 318:1-32
McLean, J. H. 1989a. New archaeogastropod limpets from ludrothermal vents: new famiK Peltospiridae, new su- perfamiK Peltospiracea, Zoologica Scripta 18(l):49-66,
McLean, J. H. 1989b. New slit-limpets (ScLssurellacea and Fissurellacea) from hvdrot hernial \ents Part 1 Systematic descriptions and comparisons based on shell and radular characters. Contributions in Science, Natural Histor\ Mu- seum of Los .Angeles County, no. 407:1-29
Nakamura, H, K, 1986. New archaeogastropod superfamiK Neomphalacea. Venus, The Japanese Journal of Malacol- ogy 45(2): 138-140 [review article in Japanese].
Okutani, T. and S, Ohta. 1988. A new gastropod mollusk associated with livdrotherinal \ents in the Mariana Back-
Page 86
THE NAUTILUS, Vol. 104, No. 3
Arc Basin, western Pacific. V'eiuis, The Japanese Journal of Malacology 47(1): 1-9.
Ponder, VV. F. and A. Waren. 1988. Classification of the Caenogastropoda and Heterostropha — a list of the famiiy- grnup names and higher ta.va. /;i; Ponder, W. F. (ed.). Prosobranch phylogenv , proceedings of a symposium held at the 9th International Malacological Congress, Edin- burgh, 1986. Malacological Review, Supplement 4:288- 328.
Rath, E. 1988. Organization and systematic position of the Valvatidae. In: Ponder, VV. F. (ed.). Prosobranch phylog- eny, proceedings of a symposium held at the 9th Inter- national Malacological Congress, Edinburgh, 1986. Mal- acological Review. Supplement 4:194-204.
Ruiuiegar, B. 1983. Molluscan phylogeny revisited. Memoir of the .\.ssociation of .Australasian Paleontologists 1:121- 144.
Salvini-Plawen, L. 1980. A reconsideration of systematics in the Mollusca (phylogeny and higher classification). Mal- acologia 19:249-278.
SaKini-Plawen, L. and G. Haszprunar. 1987. The Vetigas- tropoda and the systematics of streptoneurous Gastropoda (Mollusca). Journal of Zoologv, London 211:747-770.
Sitnikova, T. Y. and Y. I. Starobogatov. 1982. Content and systematic status of the group Architaenioglossa (Gastrop- oda, Pectinibranchia). Zoologicheskii Zhurnal 61(6):831- 842.
Sitnikova, T. Y and Y. I. Starobogatov. 1983. On the taxo-
nomic position of the genus Neomphalus McLean, 1981. In: Likharev, I. M. (ed). Molluscs, their systematics, ecol- ogy and distributions. Abstracts of Conniuuiications, The USSR. Academy of Sciences, Zoological Institute, Sev- enth Meeting on the Investigation of Molluscs, p. 23-26 [In Russian].
Stein, J. L., S. C. Cary, R R Hessler, S. Ohta, R D. Vetter, J. J, Childress, and H. Felbeck. 1988. Chemoautotrophic symbiosis in a hydrothermal vent gastropod. Biological Bulletin 174:373-378.
Thiele, J. 1925. Gastropoda. /n; Kiikenthal, VV. (ed). Hand- buch der Zoologie. de Gruyter, Berlin, 5(1,2):38-155,
Tunnicliffe, V. 1988, Biogeography and evolution of hydro- thermal-vent fauna in the eastern Pacific Ocean. Pro- ceedings of the Royal Societv of London, series B, 233: 347-366.
Turner, R. D , R A. Lutz, and D Jablonski. 1985. Modes of molluscan larval development at deep-sea hydrothermal vents. In: Jones, M. L. (ed). The hydrothermal vents of the eastern Pacific: an overview. Bulletin of the Biological Society ot Washington, no. 6:167-184.
Waren, A. 1990 Ontogenetic changes in the trochoidean (Archaeogastropoda) radula, with some phylogenetic in- terpretations. Zoologica Scripta, In press,
Waren, \. and P. Bouchet. 1989 New gastropods from East Pacific hvdrothermal vents, Zoologica Scripta 18(1):67- 102.
THE NAUTILUS 104(3):87-91, 1990
Page 87
Shell Dissolution Rate in Freshwater Pulmonate Snails: Influence of Periostracum and Water Chemistry
R. Douglas Hunter
Department of Biological Sciences
Oakland University
Rochester, MI 48309-4401, USA
ABSTRACT
The size-specific rate of shell dissolution was measured in situ in three Michigan lakes that differed in pH and calcium con- centration using shells of two species of freshwater pulmonate snails. Physella integra (Haldeman 1S41 ) and Helisoma anceps (Menke 1830). Lack of a periostracum resulted in significantK higher rates of dissolution as did exposure to lake water with either low pH and/or low [Ca-*]. Three-factor ANOV'A indi- cated significant effects for periostracum condition and site as well as significant two and three-way interactions.
For H. anceps (but not P. integra) the periostracum appears to greatly reduce the rate of shell dissolution hence ma\' serve to reduce shell damage in acid waters. .Adverse water chemistry (low pH and or low Ca'*) has a much greater effect on shell dissolution across species (CD = 81 S) than does presence or absence of periostracum (CD = 4'^).
Shell dissolution response to water chemistry as well as the degree of periostracum protection differs between these two species of snails. Models of lake acidification involving either Ca-* flux and pool sizes or mollusk population survival may need to consider such differences.
Key words: .-Acidification; pH; calcium; snail; shell; perios- tracum; dissolution; freshwater.
INTRODUCTION
Freshwater mollusks are known to be more sensitive to acidification of their habitat than other benthic groups (Okland & Okland, 1986). Although shell erosion of adult snails and certain physiological processes are influenced by exposure to acid waters, the egg and juvenile stages are most severely affected (Zischke et ai, 1983; Rooke & Mackie, 1984; Burton e^ a/., 1985; Hunter, 1988, 1990). This sensitivity of early developmental stages is also ob- served in waters of low calcium concentration due to the importance of calcium in normal molluscan physiology (Rooke & Mackie, 1984; Hunter, 1990). It is now evident that the disappearance of mollusk populations from lakes or streams affected by acidic deposition is due to re- cruitment failure as a result of developmental arrest and poor juvenile survival (Hunter, 1988, 1990; Shaw & Mackie, 1989). In contrast to eggs and juveniles, adult snails are relatively resistant to short-term exposure to
moderate (pH 5-6) levels of acidity (Servos & Mackie, 1986); however they commonly develop shell damage, such as pitting, as a result. Longer term exposure at slightly higher (but still subneutral) pH may also result in shell pitting. Evidence of shell dissolution in adult snails may therefore provide an early indication that the population is at risk from recruitment failure (Hunter, 1988). .■\lthough it might appear that one could make such a determination based on measurement of ambient physico-chemical parameters (e.g.. pH, [Ca'*], dissolv- ed inorganic carbon, etc.), such measures are indirect indicators of stress on an ac}uatic mollusk population hence, at best, are useful only as general indicators. Ev- idence cited in Okland and Okland (1986) suggests there is a wide range of tolerances to high [H*] among species of freshwater mollusks. This is likeK compounded by interpopulation variation in tolerance, making it difficult to predict at precisely what pH level one would e.xpect a particular species-population to begin showing stress. Results that examine the interaction of pH and [Ca-*] in terms of adverse effects on fecundity, dexelopment, and juvenile survival in a pulmonate snail have been reported elsewhere (Hunter, 1990). The purpose of this study was to measure the rate of shell dissolution using shells of two species of freshwater pulmonate snails, some v\ith periostracum (proteinaceous outer shell la\ er), some w ithout it, in lakes with different pH and [Ca-*] condi- tions. Interspecific differences, influence of the perios- tracum, and lake differences insofar as they might mod- iiy the rate of shell dissolution were of particular interest.
MATERIALS AND METHODS
The shells of two species of freshwater pulmonate snails were used in this study. Shells of Physelh ("Physa") integra and Helisoma anceps originated from Douglas Lake, Cheboygan Co., Michigan, I'S.A. Empt\ shells from adult-size animals that had died w ithin the past 24 hours were obtained from aquaria of concurrent culturing ex- periments. Any remaining debris inside these shells was removed by a jet of distilled water into the aperture after w Inch the shells were air-dried. Such shells had a fully intact periostracum. Living snails were not used because
Page 88
THE NAUTILUS, Vol. 104, No. 3
they deposit shell even while previously secreted CaCOa is undergoing dissolution. Hence the use of gravimetric methods to measure rates of loss would be confounded by simultaneous additions to and removal from the shell mass.
Shells w ithout a periostracum were obtained from as- sorted shells (probabK <5 years old) that had washed up above water level where the periostracum was lost by natural (aerial) weathering. These latter shells con- trasted markedly with those having an intact periostra- cum b\ lacking most of the characteristic color and glossy sheen of the shells of living snails, instead having a matte, chalk) white appearance. Shells that were eroded, pitted, or strongly discolored, were avoided.
The apertures of both kinds of shells were completely sealed with silicone aquarium sealer so as to prevent erosion of shell material from the inner surface (nacreous layer) of the shells. This assured that any shell loss by dissolution would be from the outer surfaces of the shell onK. Shells were then dried at 10.5 ± 5 °C to a constant weight and placed into numbered mesh bags ("bridal veil" of 1 mm- mesh size). The bags were then enclosed in styrene plastic boxes with screened tops and bottoms and attached to stakes securely driven into the bottoms of three selected lakes. The lakes in whicli the shells were submerged are identified below along w ith the means of three calcium and pH measurements (taken near shore at 0.5 m). These study sites were all located on protected (windward) shores.
1. Douglas Lake, Cheboygan Co., MI: high calcium (35.4 mg Ca^VD; high pH (8.59).
2. Vincent Lake, Cheboygan Co., MI: low calcium (3.5 mg Ca-+/L); high pH (7.78).
3. Lake Nita, Alger Co., MI: low calcium (3.0 mg Ca-*/ L); low pH (5.47).
No mollusks are presently found in either Vincent or Nita; however, H. anceps (with pitted shells) occurred in Vincent Lake up to a few years ago.
The experimental design was factorial with three sites, two species, and two periostracum conditions giving 3 X 2 X 2 = 12 treatments. Each treatment involved ten replicate shells or 120 total shells. Shells remained in situ at 0.25-0.5 m depth for 42 days at Douglas Lake and Vincent Lake and 45 days at Lake Nita, after w hich they were removed, dried, and weighed. Change in shell mass was computed from weights before and after dr\ing, then (assuming linear weight loss) converted to a rate by dividing by the number of days. Since larger shells lose more CaC03 per unit time than smaller shells, small differences in starting shell size among treatments were compensated for b> dividing dissolution rate b> shell size (maximum shell dimension), hence the data are ex- pressed as bi/.c-sppcific dissolution rate which is ;ug CaCO,, dissoKed per tma shell dimension day.
Differences am. mx treatments were evaluated using one and three factor .WOVA and Fishers Protected Least Significani iWev^.ncr Procedure (PLSD). The latter is a two-stage proc\"J.urf. w lere an overall test of significance
(standard F-test) is followed by pairwise comparisons if the F-test is significant at the chosen alpha level (Koop- mans, 1987).
RESULTS
Figure 1 shows mean size-specific dissolution rate for all twelve treatment groups. Results of a one-factor ANOVA indicated that there were significant differences among treatments (F,,, i,,,, = 116.99, P < 0.0001). Treatment histograms having a common letter are not significantly different from each other by Fishers PLSD (a = 0.05). These data indicate that there are substantial site and periostracum effects; e.g., shell dissolution is minimal at Douglas Lake (<3 /ig/'(mmday) for either species whether the periostracum is present or absent. In con- trast, the Vincent Lake site (high pH, low [Ca-^]) pro- duced dissolution rates that were intermediate, ranging from 9.7 ^g/(mm-day) for H. anceps shells with peri- ostracum to27.2^g/(mmda\ ) for H. anceps shells with- out periostracum. The highest rates of shell dissolution occurred at Lake Nita (low pH, low [Ca-*]) ranging from 17.7 ^g/(mm-day) for H. anceps with periostracum to 58.7 /ig/(mmday) for H. anceps without periostracum. Dissolution rates for P. integra shells with periostracum were higher than the above rates for H. anceps. Physella integra shells with periostracum at Vincent Lake lost mass at 15.1 ^g/(mmdaN ) while those at Lake Nita lost mass at 36.7 /jg/(mmday). Without periostracum, how- ever, P. integra rates were lower than those for H. an- ceps: 19.8 /xg/(mmday) at Vincent Lake and 39.7 ng/ (mm -day) at Lake Nita.
It can also be seen from figure 1 that absence of a periostracum in H. anceps greatly increased the shell dissolution rate of that species, however, in P. integra the dissolution rate was only slightly increased by lack of a periostracum. and the difference was not significant. In H. anceps the lack of a periostracum resulted in a dissolution rate that is over two (at N'incent Lake) or three times greater (at Lake Nita) than at Douglas Lake.
The degree to which size-specific dissolution rate is influenced by the three main effects (site, species, peri- ostracum condition) is expressed in table 1. which gives the results of a three-factor ANOVA (SPSS-X). Since the data were neither normally distributed nor were the variances of the treatment means equal, a square root transformation was used. Both site and periostracum con- dition had significant effects on size-specific dissolution rate; for site, F. „):,. = 712.84 (P < 0.001) and for peri- ostracum condition, F,i ,03) = 63.92 (P < 0.001). There was no significant effect for species; i.e.. P. integra and //. anceps shells had similar rates of dissolution when considered as species groups across the three sites. The size-specific rate of dissolution was influenced more by site differences than b\ presence or absence of a perios- tracum. The coefficient of determination for site = 81% whereas that for periostracum condition = 4%.
Table 1 also indicates that there are significant two- aiid three-wav interactions between the main effects.
R D. Hunter, 1990
Page 89
a
X)
E E
60
50-
40
S^ 30
■^ 20 ■
o b
|
b T |
T |
|||
|
c |
c |
|||
|
_o_ g |
X.
DL DL VL VL LN LN + - + - + -
Helisoma onceps
DL DL VL VL LN LN
+ - + - + -
Physella Integra
Figure 1. Size specific shell dissokitioii rates (x ± SE) lor P. Integra and H. anceps with ( + ) and without ( — ) periostracum at three lakes: DL = high pH, high Ca-* site; VL = high pH, low Ca-* site; LN = low pH, low Ca-* site. Histograms with the same letter over them are not siguificantK different bv Fishers PLSD (a = 0.05). N = 10 for all treatments.
Specifically, the shell dissolution rate of either species at a particular site is dependent on periostracum condition. Assuming a constant dissolution rate at summer lake surface temperatures, one can calculate the number of days required for dissolution losses to equal the entire mass of an average size shell. Using a mean dry shell weight of 70.9 mg for P. Integra and 77.7 mg for H. anceps, it would take 8,273 days and 2,472 days, re- spectively, for a typical adult-size shell, with intact peri- ostracum at Douglas Lake, to completely dissolve. At Vincent Lake, these figures are lowered to 424 days for P. Integra and 768 da\s for H. anceps (both with peri- ostracum), and at Lake Nita they are further lowered to 178 days for P. Integra and 368 days for H. anceps. The shortest time to complete dissolution would be 118 days for an H. anceps shell, without periostracum, in Lake Nita.
DISCUSSION
The results presented herein suggest that the periostra- cum of Physella Integra shells offers little protection against shell dissolution due either to low ambient [Ca-*] or to low pH. For Helisoma anceps, however, the pres- ence of an intact periostracum substantialK reduces shell loss in lakes of low [Ca-*]. For example, in Vincent Lake (low [Ca-*], high pH), shell loss was reduced by 64.6% when compared to shells without a periostracum. Simi- larly, at an acid lake (Lake Nita) where both low [Ca-*] and low pH occurred, the presence of a periostracum reduced shell dissolution by 69.8'^(:. Hence in H. anceps the presence of an intact periostracum may reduce shell damage in slightly acid waters.
Table 1 . Results of three factor ANO\'A on size-specific shell dissolution rate data tor Physella integra and Helisoma anceps at three different lakes and with periostracum either present or al)sent. Data were square root transformed.
|
Degrees |
|||
|
of |
Mean |
||
|
Source of \ariation |
freedom |
square |
F |
|
Main effects |
|||
|
Site |
2 |
265.60 |
712.84* |
|
Species |
1 |
0.00 |
0 00 ns |
|
Periostracum |
1 |
23.82 |
63.92* |
|
Two-way interaction |
|||
|
Site X species |
2 |
0.71 |
1.91 ns |
|
Site X periostracum |
2 |
17.64 |
47.35* |
|
Species x periostrac\mi |
1 |
14.49 |
38.88* |
|
Three-way interaction |
|||
|
Site X species x |
|||
|
periostracum |
2 |
9.92 |
26.61* |
|
Error |
103 |
0.37 |
|
|
Total |
114 |
5,78 |
*P < 0,001; ns = P > 0.05.
The method used to obtain periostracum-free shells was to select weathered shells from debris above the high- water line. These w eathered shells had been exposed to sun, dr\ing, freeze-thaw, etc., for a few months/years. It is not known if this weathering did more than simply cause the loss of the periostracum; i.e., does such treat- ment alter the dissolution rate? If so, the effect is likely to be small based on the fact that for P. integra there is no significant difference in dissolution rate between weathered (= periostracum-free) and unweathered (= with periostracum) shells at all three sites (see table 1).
The periostracum is the outermost laser of mollusk shells and is entireK organic, consisting largeK' of con- chiolin, a quinone-tanned protein (Wilbur, 1964). Below this layer lies most of the mass of the shell which is calcium carbonate secreted in a protein matrix.
Most of the references to periostracum function in the literature are to prosobranchs or bivalves (Wilbur, 1964; Digby. 1968; Tevesz & Carter, 1980). Fretter and Gra- ham (1962) suggest that, for prosobranch snails and la- niellibranchs, the function is to reduce shell erosion. It is not clear if this is a reference to mechanical abrasion, chemical dissolution or both. In .some groups, such as burrowing and boring bivalves, there is a substantial peri- ostracum that apparently protects against mechanical abrasion (Morton, 1964; Yonge & Thompson, 1976). Tev- esz and Carter (1980) suggest that the unionacean peri- ostracum is one of the most important adaptations of this group to prevent shell dissolution. A variety of peri- ostracum functions have been suggested for bivalves, including minimization of encrusting b\- epizooans, re- sistance to boring and attack by other predators, in- creased stabilit) in the substratum, and decreased effect of substratum scour (Bottjer & Carter, 1980; Wright & Francis, 1984). .\lthough working w ith h\drothermal vent
^J»
P^K^
*t»L» »
"m 1
rt
Fiige 90
THE NAUTII IS, Vol. 104, No, 3
KKM
tKK
»».«
►.»:>
•"»
» » •
bivalves. Hunt (1987) observed that periostraca might, among other functions, provide protection of the mature shell from chemical dissolution. In a study of marine bivalves, Swinehart and Smith (1979:380) suggested that magnesium and iron in the periostracum could "act as a defensive buffer against degradation from acidic con- ditions.'
In freshwater pulmonate snails, the periostracum is relatively thin and generally lacks hair-like projections that are found in certain bivalve groups. There is little in the literature to suggest a function for the periostracum in this group of snails.
Further evidence that the periostracum provides some protection against shell erosion is derived from casual field observations that pulmonates from stressful envi- ronments often have deeply pitted shells. It is likely that once a small area of periostracum has become worn away (usually abraded by mechanical damage) then the ex- posed underlying shell dissolves more rapidly than un- affected areas nearby. The result is a pit in the shell that, in time, may open into a perforation possibly leading to the death of that individual. Although extensive wear and pitting is often observed in the umbonal region of freshwater bivalves, such wear is likely a result of the physical process of abrasion, rather than of chemical effects (Hinch & Green, 1988). Bivalve shells, which are in contact with interstitial water of the substratum over much of the shell area, are subject to somewhat different (moderated) physico-chemical conditions than are pul- monate snails, which are usually located on the surfaces of stones, vegetation, sediment, etc., hence are more di- rectly exposed to lake or stream water conditions. Hinch and Green (1988) argue that increased shell erosion in bivalves most likely results from physical etching due to water turbulence rather than from chemical dissolution. However, chemical dissolution rates would also be ele- vated by conditions of water turbulence and should not be ruled out. The same authors found that bivalve shell etching was not related to water chemistry (alkalinity and pH levels) and it may be that the nacroprismatic shell microstructure of unionaceans is substantially more resistant to dissolution than that of freshwater pulmo- nates (Tevesz & Carter, 1980; Hinch & Green, 1988).
It is not surprising that contact by snail shells with lake water low in calcium or low in both calcium and pH substantially increases the rate of shell dissolution. In a laboratory study, whole animal [Ca^+] of Planorbella trivolvis, after 53 days of exposure to pH 4.9, decreased 16% on a dry weight basis and 14% on a size-specific basis (Hunter, 1988). In that same study it was reported that ashed shells (essentially CaCOg without the perios- tracum or any other organic material) lost CaCOa about 4.6 times faster than did the shells of live animals. One may envision tile shcli as a non-living mass of CaCOa which is in direct contact with and responsive to calcium- deficient or acid water, d-rpit-e beino a part of a '' ' niollusk.
Wh;^ IS perhaps unexpecU-<i differcT.t resL",>nse b\' the siiel!
volved in this study. Comparing tl size-specific disso- lution rate of shells exposed to Vin( nt Lake water (low [Ca-^], circumneutral pH) with tha jf shells exposed to Douglas Lake water (high [Ca-+], sli itly alkaline water), P. Integra showed a 43-fold incre e and H. anceps a 6-fold increase in dissolution rate In other words, P. Integra shells with intact periostrai were far more sen- sitive to dissolution-inducing condi ins than were shells of H. anceps. Interestingly, H. a, eps shells were the more sensitive of the two specie; o the absence of a periostracum. Thus, P. Integra she are moderately sen- sitive to dissolution-inducing coi itions, whether the periostracum is present or not. I contrast, H. anceps shells with periostracum are less ; isitive to dissolution than those of P. Integra, but with' t a periostracum, H. anceps shells are considerably mo sensitive. This study suggests that the periostracum in ; ne snail species (e.g., H. anceps) could act as a detern l to shell dissolution. In populations that are in locati acidification, the life of adults n pared to other species {e.g., P. it
Clearly, either the paucity of x-* ions in the water or relatively low pH may result i higher rates of loss of shell mass in pulmonate snails, 'ata from this study indicate that when both conditic occur (which is typ- ical of acid lakes) that the shell c solution rate is higher than it is for lakes having low Ja^^] and neutral or alkaline pH. It is not possible frc this study to know if pH and [Ca-^] are acting syner; tically; however data from another study indicate th such is not the case, i.e., effects of low [Ca^*] and 1 v pH on growth and fecundity of snails reared in th lab are no more than additive (Hunter, 1990).
This study demonstrates that egree of periostracum protection and shell dissolution ites may differ signifi- cantly between species, hence. ^aCOj loss cannot be assumed to be identical for all reshwater snails. Such considerations are of potential terest in the modeling of lake acidification processes eier in terms of the dis- appearance of specific mollusci taxa from the benthos in a regime of continual pH an alkalinity reduction or calcium release by biota to freiion pools.
s subject to gradual be prolonged com-
gra)
livmg
ACKNOWLEDGEMENTS
I would like to thank the Oak Committee for the Faculty I enabled me to work at the Un logical Station in Summer, 198 especially Bob Vande Kopple, expert assistance. Thanks are (OU Mathematics), who helpei ods.
LITERATURE CITED
id University Research search Fellowship that ersity of Michigan Bio- and the staff at UMBS, )r their cooperation and so due to Mary Coffey vith the statistical meth-
ihat triere is such a ''---' ■V.'-' snecies iri-
Bottjer, D J and J. G. Carter. )80. Functional and phylo- geiietic significance of projei ng periostraca! structures in
• I
1BL
]}£
R. D. Hunter 1990
the Bivalvi (Mollusca). Journal of Paleontology 54:200- 216.
Burton, T. M., ) M. Stanford, and J. W Allen 1985 Acid- ification ef ^ts on stream biota and organic matter pro- cessing. Ca dian Journal of Fisheries and .Aquatic Science 42:669-67c
Digby, P. S B 968. The mechanism of calcification in the molluscan ; ^11. In: Fretter, V. (ed.). Studies in the struc- ture, physii gy, and ecology of molluscs. .Academic Press, New York, 93-107.
Fretter, \ . and Graham. 1962 British prosobranch mol- luscs. Ray 5^ iety, London. 755 p.
Hinch, S. G. am I. H. Green. 1988. Shell etching on clams from low-al linity Ontario lakes: a physical or chemical process? Ca dian Journal of Fisheries and Aquatic Sci- ence 45:211 2113.
Hunt, S. 1987. mino acid composition ot periostracal pro- teins from 1 lluscs living in the vicinity of deep sea hy- drothermal nts. Comparative Biochemistry and Physi- ology 88B:1 3-1022.
Hunter, R. D. 1' 8. Effects of acid water on shells, embryos, and juvenile irvival of Planorbella tricolvis (Gastropoda: Pulmonata): laboratory study. Journal of Freshwater Ecology 4:3 -327.
Hunter, R. D, 90. Effects of low pH and low calcium concentratic in the pulmonale snail, Planorbella trivol- vis: a labora y study, Canadian Journal of Zoology 68: 1578-1583,
Koopmans, L, H, 987, Introduction to contemporary statis- tical method 2nd ed, Duxbury Press, Boston, MA,
Morton, J, E, 1£ . Locomotion, In: Wilbur, K. M. and C. M. Yonge (ec i. Physiology of Mollusca, Vol, I. Academic Press, New ^ k, p. 383-423,
Okiand, J. and K . Okland, 1986. The effects of acid de- position on L thic animals in lakes and streams Exper- ientia 42:471 86,
Rooke, J B and G L Mackie. 1984. Growth and production of three species of molluscs in si.\ low alkalinity lakes in Ontario, Canada. C>'anadian Journal of Zoology 62:1474-
1478.
Servos, M R and G L. Mackie. 1986. The effect of short- term acidification during spring snowmelt on selected Mol- lusca in south-central Ontario. Canadian Journal of Zo- ology 64:1690-1695.
Shau, M, A, and G. L Mackie, 1989, Reproductive success of Amnicola limosa (Gastropoda) in low alkalinity lakes in south-central Ontario. Canadian Journal of Fisheries and Aquatic Science 46:863-869,
S\\ inehart, J H, and K, W, Smith, 1979. Iron and manganese deposition in the periostraca of several bivalve molluscs. Biological Bulletin 156:.369-381.
Tevesz, M. J, S and J, G Carter 1980, Environmental re- lationships of shell form and structure of unionacean bi- \alves. In: Rhnads. D C and R. A, Lutz (eds,). Skeletal growth ot aquatic organisms. Plenum Press, New York, p 295-322,
Wilbur, K. M. 1964, Shell formation and regeneration. In: Wilbur, K, M, and C, M, Yonge ^eds,). Physiology of Mol- lusca, Vol, I, Academic Press, New York, p, 243-282,
Wright, M. M, and L, Francis 1984, Predator deterrance by flexible shell extensions of the horse mussel. Modiolus mo- diolus. \eliger 27:140-142,
Yonge, C. M. and T. E, Thompson, 1976, Li\ing marine molluscs, Wm, Collins Sons, Ltd,, London. 288 p,
Zischke, J. A., J, W, Arthur, K. J Nordlie, R, O, Hermanutz, D, A, Standen, and T, P. Henry, 1983. Acidification effects on macroinvertebrates and fathead minnows (Pi- mephales promelas) in outdoor experimental channels. Water Research 17:47-63.
.\^K^\\S^:<*
t • f *
*4
< 4P^
Page 90
THE NAUTILUS, Vol. 104, No. 3
bivalves, Hunt (1987) observed that periostraca might, among other functions, provide protection of the mature shell from chemical dissolution. In a study of marine bivalves, Swinehart and Smith (1979:380) suggested that magnesium and iron in the periostracum could "act as a defensive buffer against degradation from acidic con- ditions."
In freshwater pulmonate snails, the periostracum is relatively thin and generally lacks hair-like projections that are found in certain bivalve groups. There is little in tile literature to suggest a function for the periostracum in this group of snails.
Further evidence that the periostracum provides some protection against shell erosion is derived from casual field observations that pulmonates from stressful envi- ronments often have deeply pitted shells. It is likely that once a small area of periostracum has become worn away (usually abraded by mechanical damage) then the ex- posed underKing shell dissolves more rapidly than un- affected areas nearby. The result is a pit in the shell that, in time, may open into a perforation possibly leading to the death of that individual. Although e.xtensive wear and pitting is often observed in the umbonal region of freshwater bivalves, such wear is likely a result of the physical process of abrasion, rather than of chemical effects (Hinch & Green, 1988). Bivalve shells, which are in contact with interstitial water of the substratum over much of the shell area, are subject to somewhat different (moderated) physico-chemical conditions than are pul- monate snails, which are usually located on the surfaces of stones, vegetation, sediment, etc., hence are more di- rect!) exposed to lake or stream water conditions. Hinch and Green (1988) argue that increased shell erosion in bivalves most likely results from physical etching due to water turbulence rather than from chemical dissolution. However, chemical dissolution rates would also be ele- vated by conditions of water turbulence and should not be ruled out. The same authors found that bivalve shell etching was not related to water chemistry (alkalinity and pH levels) and it may be that the nacroprismatic shell microstructure of unioiiaceans is substantialK more resistant to dissolution than that of freshwater pulmo- nates (Tevesz & Carter, 1980; Hinch & Green, 1988).
It is not surprising that contact by snail shells with lake water low in calcium or low in both calcium and pH substantially increases the rate of shell dissolution. In a laboratory study, whole animal [Ca-*] of Planorbella trivolvis, after 53 days of exposure to pH 4.9, decreased 16% on a dry weight basis and 14% on a size-specific basis (Hunter, 1988). In that same study it was reported that ashed shells (essentially CaC^O.j without the perios- tracum or any other organic material) lost ClaCO, about 4.6 times faster than did the shells of live animals. One may envision the shell as a non-living mass of CaCO, which is in direct contact with and responsive to calcium- deficient or acid water, despite being a part of a living mollusk.
What is perhaps unexpected is that there is such a different response by the shells of the two species in-
volved in this study. Comparing the size-specific disso- lution rate of shells exposed to X'incent Lake water (low [C^a-^j, circumneutral pH) with that of shells exposed to Douglas Lake water (high [Ca-*], slightly alkaline water), P. Integra showed a 43-fold increase and H. anceps a 6-fold increase in dissolution rate. In other words, P. Integra shells with intact periostraca were far more sen- sitive to dissolution-inducing conditions than were shells of H. anceps. Interestingly, H. anceps shells were the more sensitive of the two species to the absence of a periostracum. Thus, P. Integra shells are moderateK sen- sitive to dissolution-inducing conditions, whether the periostracum is present or not. In contrast, H. anceps shells with periostracum are less sensitive to dissolution than those of P. Integra, but without a periostracum, H. anceps shells are considerably more sensitive. This study suggests that the periostracum in some snail species {e.g., H. anceps) could act as a deterrant to shell dissolution. In populations that are in locations subject to gradual acidification, the life of adults may be prolonged com- pared to other species {e.g., P. integra).
Clearly, either the paucity of Ca-^ ions in the water or relatively low pH ma\ result in higher rates of loss of shell mass in pulmonate snails. Data from this study indicate that when both conditions occur (which is typ- ical of acid lakes) that the shell dissolution rate is higher than it is for lakes having low [Ca-^] and neutral or alkaline pH. It is not possible from this study to know if pH and [Ca-*] are acting synergistically; however data from another study indicate that such is not the case, i.e., effects of low [Ca-*] and low pH on growth and fecundit) of snails reared in the lab are no more than additive (Hunter, 1990).
This study demonstrates that degree of periostracum protection and shell dissolution rates may differ signifi- cantly between species, hence, CaCOj loss cannot be assumed to be identical for all freshwater snails. Such considerations are of potential interest in the modeling of lake acidification processes either in terms of the dis- appearance of specific molluscan taxa from the benthos in a regime of continual pH and alkalinit\ reduction or calcium release by biota to free ion pools.
ACKNOWLEDGEMENTS
I would like to thank the Oakland I'niversity Research Committee for the Faculty Research Fellowship that enabled me to work at the I'niversitN of Michigan Bio- logical Station in Summer, 1986, and the staff at UMBS, especially Bob Vande Kopple, for their cooperation and expert assistance. Thanks are also due to Mary Coffey (OU Mathematics), who helped with the statistical meth- ods.
LITERATURE CITED
Bottjer. D. J. ainl J. G, Charter, 1980. Functional and pliyio- geiietic signilicanee ol prdjctlint; pfriostiucai structures in
R. D. Hunter, 1990
Page 91
tile BivaKia (Mollusca). Journal t)f Paleontolog\ 5-1:200- 216,
Burton, T. M,, H, M. Stanford, and J W .Mien. 1985. Acid- ification effects on stream biota and organic matter pro- cessing. Canadian Journal of Fisheries and .Aquatic Science 42:669-675.
Digby, P. S B. 196S The mechanism of calcification in the molluscan shell. In: Fretter, \'. (ed.). Studies in the struc- ture, physiologN , and ecolog\ of molluscs. .\cai!emic Press, New York, p. 93-107.
Fretter, V. and A. Graham. 1962. British prosobranch mol- luscs. Ray Society, London. 755 p.
Hinch, S. G. and R. H. Green. 1988. Shell etching on clams from low-alkalinity Ontario lakes: a physical or chemical process? Canadian Journal of Fisheries and Aquatic Sci- ence 45:2110-2113.
Hunt, S, 1987. .^mino acid composition of periostracal pro- teins from molluscs living in the \ icinit\ ot deep sea hy- drothermal \ents. Comparati\e Biochemistry and Physi- ology 886:1013-1022.
Hunter, R. D. 1988. Effects of acid water on shells, embryos, and juyenile survival of Planorbella trivolvis (Gastropoda: Pulmonata): a laboratory stud\ Journal of Freshwater Ecology 4:315-327.
Hunter, R D. 1990 Effects of low pH and low calcium concentration on the puhnonate snail. Planorbella trivol- vis: a laborator\' study. Canadian Journal of Zoology 68: 1578-1583.
Koopmans, L. H. 1987. Introduction to contemporary statis- tical methods, 2nd ed. Duxbury Press, Boston, MA.
Morton, J. E. 1964. Locomotion. In: Wilbur, K. M. and C. M. Yonge (eds.). Physiology of Mollusca, Vol. I. Academic Press, New York, p. 383-423.
Okland, J, and K. A. Okland 1986 The effects of acid de- position on benthic animals in lakes and streams. Exper- ientia 42:471-486.
Rooke, J B and (; L Mackie. 1984. Growth and production of three species of molluscs in six low alkalinit) lakes in Ontario, Canada Canadian Journal of Zoology 62T474- 1478.
Servos, M. R. and G. L Mackie 1986 The effect of short- term acidification during spring snowmelt on selected Mol- lusca in south-central Ontario Canadian Journal of Zo- ology 64:1690-1695.
Shaw, M. A and G L Mackie. 1989. Reproductive success of Amnicola limosa (Gastropoda) in low alkalinity lakes in south-central Ontario, Canadian Journal of Fisheries and Aquatic Science 46:863-869,
Swinehart, J, H, and K. W, Smith. 1979. Iron and manganese deposition in the periostraca of several bivalve molluscs. Biological Bulletin 156:369-381.
Tevesz, M J S and J. G Carter. 1980. Environmental re- lationships of shell form and structure of unionacean bi- valves. In: Rhoads, D C. and R. A Lutz (eds.). Skeletal growth of aquatic organisms. Plenum Press. New York, p. 295-322.
Wilbur, K M. 1964. Shell formation and regeneration In: Wilbur, K. M. and C. M. Yonge (eds.). Physiology of Mol- lusca, \'ol, I. .Academic Press, New York, p. 243-282.
Wright, M. M and L. Francis. 1984. Predator deterrance by flexible shell extensions of the horse mussel. Modiolus mo- diolus. N'eliger 27:140-142.
Yonge, C. M, and T E. Thompson 1976 Living marine molluscs. Wm. Collins Sons, Ltd., London. 288 p.
Zischke, J. A., J. W. Arthur, K. J. Nordlie, R. O. Hermanutz, D. A. Standen, and T. P. Henry. 1983. Acidification effects on macroinvertebrates and fathead minnows (Pi- mephales promelas) in outdoor experimental channels. Water Research 17:47-63.
THE NAUTILUS 104(3):92-95, 1990
Page 92
Effect of Experimentally Induced Shell Damage on Mortality, Reproduction and Growth in Helisoma trivolvis (Say, 1816)
Thomas Stahl David M. Lodge'
Department of Biological Sciences University of Notre Dame Notre Dame, IN 46556, USA
ABSTRACT
We conducted a replicated laboratory experiment to test the potential effect of shell damage (imitating that inflicted by craxfish) on mortality, reproduction, and shell growth of the snail Helisoma trivolvis (Say, 1816). During the egg-laying period of the snail, we removed 0, 2, 4 or 9 mm of shell from the aperture. For the subsequent 29 days, we monitored snail egg production, mortality, and shell growth. We predicted that because of phssiological trade-offs, snails would either repair their shell and show decreased egg production and mortality (Hypothesis 1), or forego repair and show high egg production and early (or high) mortality (Hypothesis 2).
Results were inconsistent with both hypotheses. Only shell growth differed significantly (p < 0.05) among damage treat- ments, with growth positively related to damage. Our data do not conclusiveK refute the trade-off assumption. However, the results tlo strongly suggest that non-lethal shell damage, like that indicted by crayfish, is unlikely to affect snail population growth.
Key words: Helisoma, Orconectes, predation, damage, trade- off, repair, snails, crayfish.
INTRODUCTION
Snails and their predators have coevolved in ways that enhance their ability to survive predation and to catch prey, respectively (Vermeij and Covich, 1978). The im- portance of predation on marine snails is supported by an abundance of observations (Norton, 1988; Raffaelli, 1978; Vermeij, 1979, 1982; Vermeij and Covich, 1978) and experimental evidence (Garrity et ai. 1986). Fresh- water gastropods, however, have developed far fewer antipredatory shell features than marine gastropods, per- haps because of limited minerals in fresh water, insuf- ficient time for coevolution (due to the relatively young age of most freshwater bodies), and a lower diversity of predators in fresh water (Vermeij and Covich, 1978).
' Author to whom correspondence should be addressed.
Recent evidence suggests, though, that freshw ater snails are readily eaten by both shell-invading predators like leeches (Brown and Strouse, 1988) and shell-crushing predators like redear sunfish (Stein ct at.. 1984), pump- kinseed sunfish (Osenberg and Mittelbach, 1989), and crayfish (Crowl, 1989; Lodge and Lorman, 1987; Olsen, 1989; Weber and Lodge, 1990). Probably because of their relatively high feeding rate, e.g., 50-200 Hydrobiaciay- fish '-day ' (Olsen, 1989), and frequently high densities (Lodge et ai, 1987), crayfish (Orconectes spp. ) appear to be particularly potent predators of snails. Field ob- servations (Weber and Lodge, 1990) and experimental (Lodge and Lorman, 1987; Lodge, unpublished data) evidence suggest that crayfish predation influences abun- dance and species composition of snails in northern Wis- consin lakes. Indirect effects of predation, such as the non-lethal shell damage documented extensiveK for ma- rine snails (Geller, 1990; Raffaelli, 1978; Vermeij, 1982; Vermeij et ai, 1980; Vale and Rex, 1989; Zipser and Vermeij, 1980), may have an impact on snail populations by reducing individual fitness. An experimental test of this possibility, which has not been previously explored for freshwater snails, is the topic of this paper.
In laboratory experiments in which freshwater Or- conectes crayfish prey on snails, predation rate differs among snail species (A. P. Covich, personal communi- cation), but intermediate sized shells (6-9 mm) are most often non-lethally damaged (Olsen, 1989). Smaller snails are almost always successfully eaten; larger snails, which have stronger shells, are not handled as easily. In labo- ratory experiments, Orconectes rusticus (Girard, 1852) (31-39 mm carapace length) eat about 7% and non- lethally damage (>1 mm shell aperture peeled awa\ ) about 25% of 60 Helisoma available to single cra\fish in one night (Olsen 1989). In this paper, we test the impact on snail mortality, fecundit), and shell growth of ex- perimentally induced damage that mimicked the cray- fish-inflicted damage described by Olsen (1989).
Our experiment v\as designed to test two opposing Inpotheses regarding the effects of non-lethal damage on reproductively active snails. Both hypotheses are built
T. Stahl and D. Lodge, 1990
Page 93
on the assumption that trade-offs (sensu Tilman, 1989) exist in the allocation of resources b\' individual snails to repair, growth and reproduction. The trade-off assump- tion, e.g., that energy spent on growth decreases energy available for reproduction, is a critical component in much ecological and evolutionary thought, to the point of becoming a paradigm (Tilman, 1989).
Hypothesis 1 is that a damaged snail will divert energy and nutrients from growth and reproduction to repair its damaged shell. If this occurs, non-lethal shell damage b> a predator might limit snail populations even though the snail is not killed. Hypothesis 2 is that a snail would respond to non-lethal damage by foregoing repair and putting all of its energy into reproduction (Kirkwood, 1981 ). This might be the expected result for semelparous snails, like the Helisoma used in our experiment (see Boerger, 1975 for description of Helisoma life cycle). If H\ pothesis 1 is correct, we predicted damaged Helisoma would exhibit low fecundity, and low or delayed mor- talit\-. In this case, non-lethal damage might depress snail populations. If Hypothesis 2 is correct, we predicted damaged snails would exhibit fecundity similar to un- damaged snails and early, high mortality rates. In this case, non-lethal damage would have a negligible effect on snail populations.
MATERIALS AND METHODS
The experiment was conducted at the University of Notre Dame Environmental Research Center (L'NDERC) in the Upper Peninsula of Michigan (46°N, 89°W) during the latter part (1 June-1 July 1989) of the reproductive season of H. trivolvis (Boerger, 1975). Adult snails (mean shell diameter of 24.6 mm, range = 21-29 mm) were collected from Mullahy and Ward lakes, two small me- sotrophic lakes on UNDERC propert\ .
This size range of snails was used because it was most available. While these snails are larger than those most susceptible to non-lethal damage (Olsen, 1989), we as- sume response to damage would be similar to that of species w hose reproductive size is smaller, e.g., Helisoma campanulata (Say).
Shells were artificially damaged by peeling 0, 2, 4, or 9 mm ring of shell from the aperture with forceps. The living tissue of all snails was undamaged. There were seven replicates for each of the four damage treatments. Each of the 28 experimental units was a shallow fiberglass tray (30 x 35 x 8.5 cm deep), filled to a depth of 5 cm with lake water. Snails were randomly assigned to treat- ments, and trays randomly assigned to a lab bench po- sition. Trays were maintained with natural lighting from windows. Temperature fluctuated in the range 14-21 °C. Each tray contained 10 snails (all with the same degree of damage) and 2-3 periphyton covered rocks (6-10 cm diameter) to provide snail food. Food le\el was kept as constant as possible throughout the experiment by re- placing water and rocks about once per week (three times during the experiment). Snail mortalities and egg sacs were counted every other day. Dead snails were re-
300 n
200-
O
< y, 1 00 -
U
X
~ <
U
12 16 20 24 2i
0 mm damage 2 mm damage 4 mm damage 9 mm damage
TiMK (I).^^S)
Figure I. Mean (N = 7) cumulative number of eggs per 10 snails as a function of time. No significant difference in total egg production (day 29) existed among treatments (.\NOV'.>\ p = 0 40) Figure 2. Mean (N = 7) cumulative deaths per 10 snails as a function of time. Mean for 0 damage treatment is zero from day 0 through day 8. Differences among treatments in total mortality (da\ 29) were margitialK significant (.WOX'.^ p = 0.052). For figures 1 and 2, ± 1 SE is indicated for day 29 onl\ .
moved. Egg sacs were collected with a .scalpel from tray sides, rocks, and shells of snails. Eggs in each egg sac were counted under a dissecting microscope. Every snail was measured for new shell growth near the end of the experiment (24 June).
We tested differences among treatments in egg pro- duction, mortality, and shell growth with a separate ANOVA for each response.
Page 94
THE NAUTILUS, Vol. 104, No. 3
1.2
1.0-
E
^ 0,8i
s
o cc o
u
X
1/3
z
<
bd
0.6
0.4-
0.2-
0.0-
DAMAGE (mm)
Figure 3. Histogram of mean shell growth (N = 7) ±2 SE for the four shell damage treatments (ANOVA p < 0.001). The horizontal bar connects treatments that did not differ (p > 0.05, Tukey's Test).
RESULTS
For all four damage levels, cumulative egg production increased through about day 12, and began to level off thereafter as egg-laying ceased (figure 1). No differences existed among treatments in total eggs laid (ANOVA p = 0.40 for day 29 data).
Mortality was very low in all treatments through the egg-laying period, and began to increase in all treatments after egg-laying ceased (figure 2). On day 29, there was a marginally significant difference among treatments in total mortality (ANOVA p = 0.052), but the apparent rank order of mortality was not correlated to inflicted damage levels.
Shells in all treatments grew during the experiment, with growth differing among treatments (ANOVA p < 0.001) and generally positively related to damage level (figure 3). Regrown shell on damaged snails was very thin compared to the rest of the shell. This, along witli the original fracture line, made it easy to measure growth on damaged snails. On control snails, however, new growth often blended in with the old shell, rendering uncertain our growth measurements for the control treat- ment. Even if control growth data were removed from consideration, the positive relation between damage and growth remains for the three damage treatments.
DISCUSSION
Differences in mortality among damage lev els were mar- ginally significant (p = 0.052), but probabl\- not biolog- ically meaningful because there is no relationship be- tween the treatment and the apparent response (figure 2). A lack of relation between damage and mortality is consistent with the conclusions of Zipser and Vermeij (1980) that shell damage does not cause mortality in marine snails. More recentK , though. Geller ( 1990) found that damaged Nucella, an intertidal snail, have higher mortality than undamaged snails. Like Helisoma, how- ever, damaged Nucella have more shell growth, and no difference in fecundity relative to undamaged snails (Geller, 1990). In Helisoma, the only response that clear- ly differed significantly among treatments was growth (figure 3), which increased with increasing damage. H. trivolvis damaged most severely regrew their shells the most (figure 3, p < 0.001), but suffered no decline in fecundity (figure 1) or any increase in mortality (figure 2). Results were therefore inconsistent with both initial hypotheses, and apparently inconsistent with the trade- off assumption underKing both hypotheses.
While this apparent contradiction of the trade-off as- sumption is intriguing, the limitations of our experiment make it premature to reject the occurrence of physio- logical trade-offs in these snails. We did not measure responses in energy or other relevant units, nor did we measure other physiological responses that may be in- volved in trade-offs, e.g., growth of living biomass, egg weight, or egg viability. Results do, however, suggest that shell growth is "hardwired," i.e., it cannot be turned off, even with senescence imminent in semelparous snails.
It is possible that a damaged snail might be more vulnerable to subsequent attacks b\ predators. We did not test this possibility , but suspect the eftect would be minor. In lab experiments where crayfish damaged shells (Olsen, 1989), crayfish appeared to curtail an attack be- cause the remaining shell was simpK- too strong to break. In addition, the earlier experiments probabK enhanced the frequency of shell damage over natural frequencies by enhancing encounter rates between predator and prey. Thus, it seems unlikely that non-lethal shell damage by cra\fish would have any impact on snail population growth.
ACKNOWLEDGEMENTS
We thank Mark Olsen for helpful suggestions on the design of this experiment, which was derived from a similar preliminary experiment conducted b\ Olsen. Thanks also go to Ronald Hellenthal, Martin Berg, Mi- chael Dini, Kathleen McTigue and students of the UN- DERC" program, who all helped in the research. Geerat Vermeij. Robert Dillon, Roy Stein, and Ken Brown pro- vided helpful reviews of the manuscript. Financial sup- port for this project was provided by the Hank Family Endowment for I'NDERC and grants to David M. Lodge (NSFBSR-8500775 and NSFBSR-8907407). This is a con-
T. Stahl and D. Lodge, 1990
Page 95
tribution from the ITniversity of Notre Dame Environ- mental Research Center.
LITERATURE CITED
Boerger, H. 1975. .\ comparison of the life c>cles. reproduc- tive ecologies, and size-weight relationships of Helisoma anceps, H. aimpai^ulata. and H trivolvis (Gastropoda, Planorbidae). Canadian Journal of Zoolog\ 53;1812-1S24.
Brown, K. M. and B. A. Strouse. 1988. Relative vulnerability of six freshwater gastropods to the leech Nephelopsis ob- scura (Verrill). Freshwater Biology 19:157-166,
Crowl. T. A. 1989. Direct and indirect effects of crayfish (Orconectes virilis) predation on snail {Physella virgata virgata ) population d\ namics in spring-fed streams. Ph.D. dissertation. The L niversits of Oklahoma, 139-1- pp.
Garrity, S. D, S. C. Levings, and HM Caffey. 1986. Spatial and temporal variation in shell crushing by fishes on rocky shores of Pacific Panama. Journal of Experimental Marine Biology and Ecology 103:131-142,
Geller. J B 1990. Reproductive responses to shell damage by the gastropod \ucclla emarginata (Deshayes). Journal of Experimental Marine Biolog) and Ecology 136:77-87.
Kirkwood, T. B. L. 1981. Repair and its evolution: survival versus reproduction. In: Townsend, C R. and P Calow (eds. ). Ph\'siological ecology: an evolutionary approach to resource use. Blackwell Scientific Publications, Boston, p. 165-189.
Lodge. D. M., K. M. Brown, S. P. Klosiewski, R. .A. Stein, A. P. Covich, and C. Bronmark 1987. Distribution of fresh- water snails: spatial scale and the relative importance of physicochemical and biotic factors. .'American Malaco- logical Bulletin 5:73-84.
Lodge, D M and J G Lorman 1987 Reductions in sub- mersed macrophyte biomass and species richness by the crayfish Orconectes rusticus. Canadian Journal of Fish- eries and Aquatic Science 44:581-597.
Norton, S. F. 1988. Role of the gastropod shell and operculum in inhibiting predation by fishes. Science 241:92-94
Olsen, T. M. 1989. Impact of the introduced crayfish, Or- conectes rusticus, in Northern Wisconsin lakes: field and laboratory studies. M.S. thesis, Universitv of .Notre Dame.
Osenberg, C W and G. G Mittelbach. 1989. Effects of body size on the predator) -prey interaction between pumpkin- seed sunfish and gastropods. Ecological Monographs .59: 405-432.
Raffaelli, D. G. 1978. The relationship between shell injuries, shell thickness and habitat characteristics of the intertidal snail Littorina rudis Maton. Journal of Molluscan Studies 44:166-170
Stein. R. A., C. G. Goodman, and E. A. Marschall. 1984. Using time and energetic measures of cost in estimating prey value of fish predators. Ecolog\ 65:702-715.
Tilman, D. 1989. Discussion: population dynamics and species interactions. In: Roughgarden, J., R. H. May, and S A. Levin (eds.). Perspectives in Ecological Theor\ Princeton University Press. Princeton, p. 89-100.
Vale, F. K. and M. A. Rex. 1989 Repaired shell damage in a complex of Rissoid gastropods from the Upper Conti- nental Slope south of New England. The Nautilus 103: 105-108.
Vermeij, G. J. 1979. Shell architecture and causes of death in micronesian reef snails. Evolution 33: 686-696.
Vermeij, G. J. 1982 Gastropod shell form, breakage, and repair in relation to predation b\ the crab Calappa. Maia- cologia 23:1-12.
Vermeij, G. J and \ P. Covich. 1978. Coevolution of fresh- water gastropods and their predators. American Naturalist 112:833-843.
Vermeij, G. J., E. Zipser, and E. C Dudley 1980 Predation in time and space: peeling and drilling in terebrid gastro- pods. Paleobiolog)' 6:352-364.
Weber, L. M. and D. M. Lodge. 1990. Periph\tic food and predatory crayfish: relative roles in determining snail dis- tribution Oecologia 82:33-39.
Zipser, E and G. J. Vermeij. 1980. Survival after nonlethal shell damage in the gastropod Conus sponsalis. Micro- nesica 16:229-234.
THE NAUTILUS 104(3):96-104, 1990
Page 96
New Gastropods from the Bermont Formation (Middle Pleistocene) of the Everglades Basin
Edward J. Peluch
Dtpartnicnt of Geology- Florida Atlantic University Boca Ralon, FL 33431, USA
ABSTRACT
Eight new gastropods are described from tfie poorly-known basal beds ("Holey Land Unit") of the middle Pleistocene Ber- mont Formation of the Everglades Basin. The new species include Cypraea (Macrocypraea) spengleri n.sp. and Cypraea (Pseudozonaria) portelli n.sp. (Cypraeidae), Melongena (Mic- cosukca) cynthiae n.sp, and Melongena {Miccosukea) holey- landica n.sp, (Melongeiiidae), Scaphella seminole n.sp. (Volu- tidae), and Conus capelettii n.sp., Contis griffini n.sp., and Conufi lemoni nsp, (Conidae). Also described is a new subgenus of Melongena Schumacher, 1817, Miecosukea n.subgen., which represents an endemic Pleistocene species radiation from within the Everglades region.
Key words: Gastropods; Pleistocene; Everglades; Florida.
INTRODUCTION
Of the major surficial stratigraphic units of the Ever- glades Basin of southern Florida, the middle Pleistocene Bermont Formation is the least known and the most poorly studied. Indeed, the formation did not even re- ceive an official designation until 1974, when DuBar informally named and described this important set of units. Previously (i.e., McGinty, 1970; Hoerle, 1970), the formation was simply referred to as "Unit A" or the "Glades Unit," or, prior to that time, as the "un-named post-Caloosahatchee formation" (i.e., E. Voices, 1968). Although the formation name still has not been accepted by regional offices of the United States Geological Survey (fide Wesley L. Miller, Water Resources Division, USGS, Miami), several workers in the Pleistocene paleontology of southern Florida have adopted its usage and recognize its importance as the "missing link" in the stratigraphic record of the Everglades region (i.e., E. Yokes, 1976, 1984; Petuch, 1988). Since the depositional center of the formation is within the Everglades Basin where there are few sampling sites, only sporadic collections of Ber- mont material have been made and the molluscan fauna, particularly the gastropod component, is known from only a handful of publications.
In response to increased building and construction in southern Florida, several large new land fill (juarries have
been excavated within the Everglades region over the last few years. Two of these in particular, the Capeletti Brothers pit #11 in northern Dade County and the Grif- fin Brothers pit on the Brow ard-Palm Beach County line, have cut into extremely fossiliferous beds of the Bermont Formation and have uncovered many new and interest- ing gastropods. Besides new species, both quarries have yielded large numbers of classic Bermont index fossils (as listed by McGinty, 1970; DuBar, 1974; and Petuch, 1988, 1989) such as Melongena (Rexmela) hispinosa (Philippi, 1844), Fasciolaria okecchobeensis Tucker and Wilson, 1932, Latirus maxwelli Pilsbry, 1942, Vasum floridanum McGinty, 1940, Fusinus watermani (M. Smith, 1940), and Stromhua mayacensis Tucker and Wil- son, 1933, demonstrating the contemporaneous nature of their beds. Several other newly-described index fossils, including Lindoliva griffini Petuch, 1988, Lindoliva spengleri Petuch, 1988, and Maica petiti Petuch, 1989 were also collected in both quarries, indicating that the dredged fossiliferous sediments came from the same stratigraphic horizon.
At both quarries, the Bermont Formation is approxi- mately 10 meters thick and is stratigraphically more complex than had previously been reported (DuBar, 1974). Of particular interest are the basal beds of the formation, w hich contain a large number of undescribed gastropod species. Although containing the same species at both localities, the basal beds in the Capeletti Brothers pit are marly and unconsolidated whereas the strati- graphic equivalents in the Griffin Brothers pit are in- durated into a thick la\ er of dense limestone. This richly fossiliferous indurated bed (figure 22), which averages 2 meters in thickness and is found at a depth of approxi- mately 15 meters below surface, has also been uncovered at construction sites in the Loxahatchee area of West Palm Beach and south of South Ba\, along the North New River Canal in central Palm Beach County. The most numerous and largest blocks of this Bermont lime- stone, however, have been dredged from the Griffin Brothers pit. Since the Griffin pit and its exposures of Bermont material are adjacent to the Holey Land Wild- life Refuge (named for the numerous shallow craters formed by World War II bombing practice, ^c/f" Howard
E. J. Petuch, 1990
Page 97
A. Griffin, Jr.), the basal indurated bed has been infor- malK referred to by local paleontologists as the "Holey Land Unit, " A cursory survey of the gastropods of the Holey Land LInit has shown that a large percentage of the species appear to be undescribed and that several belong to previousK unknown subgenera and species complexes.
In this paper, eight new gastropod species and a new gastropod subgenus are described from the basal beds ("Holey Land Unit") of the Bermont Formation. In- cluded are Cypraea (Macrocypraea) spengleri n.sp. and Cypraea (Pseudozonaria) portclli n.sp. (Cypraeidae), Melongena (Miccosiihca) cynthiae n.sp. and Melongena {Miccosiikea) holeylandica n.sp. (Melongenidae), Sca- phella Seminole n.sp. (N'olutidae), and Coniia capelettii n.sp.. Conns griffini n.sp., and Conns lemoni n.sp. (Co- nidae), and the new subgenus of Melongena, Miccosukea n.subgen. Institutional abbreviations, for the deposition of t\'pe material, include: USNM (Department of Paleo- biology, National Museum of Natural History, Smith- sonian Institution), UF (Florida Museum of Natural His- tory, Universit) of Florida, Gainesville, Florida), CM (Department of Paleontology, Carnegie Museum of Nat- ural History, Pittsburgh, Pennsylvania), and FALI (De- partment of Geology, Florida Atlantic University, Boca Raton, Florida).
SYSTEMATICS
Gastropoda
Prosobranchia
Cypraeacea
Cypraeidae
Cypraea Linnaeus, 1758
Macrocypraea Schilder, 1930
Cypraea (Macrocypraea) spengleri new species (figures 5, 6)
Material examined: HOLOTYPE — Length 107 mm, dredged from 20 m depth in Capeletti Brothers pit #11, 7 km west of Florida Turnpike, due west of Hialeah. northeastern Dade County, Florida, CM 35728; PARA- TYPES — Length (fragmentary) 105 mm, dredged from 15 ni depth in Griffin Brothers pit, 10 km west of US Highway 27, along Palm Beach-Broward County line, Florida, FAU 320; length 120 mm, internal mold, same locality as previous paratype, FAU 321; length 158 mm, same locality as previous two paratypes, Spengler col- lection. Lantana, Florida; length 83 mm, same locality as holotype, Petuch collection.
Description: Shell typical of subgenus, large, inflated, subcylindrical; aperture narrow, widening toward an- terior end, arcuate; columella (holotype) with 33 narrow teeth that extend into aperture; lip with 44 narrow teeth; fossula poorK developed, with 9 narrow teeth; base of shell rounded; auricles (extrapolated from damaged type material) well developed, projecting; color pattern (faint- ly preserved on holotype) composed of numerous small, widely-scattered round spots.
Etymology: Named for Mr. John Spengler of Lantana, F"lorida, who has helped me collect at several important fossil sites in the Everglades.
Discussion: Cypraea spengleri represents the first new- species of the subgenus Macrocypraea to be described from the fossil record of the continental United States, and is the largest cowrie known from the Neogene of Florida. The cypraeid fragments from the "Glades Unit" of the Belle Glade pit, listed by Hoerle (1970:63) as "Cypraea ?cenms Linne," are probably referable to C. spengleri. The "Cypraea cervus" from Belle Glade and Ortona Lock, listed by McGinty (1970:55), is also prob- ably C. spengleri. Based on the specimen in the Spengler collection (158 mm paratype), I also previously referred the new species to C. cervus (Petuch, 1988: plate 24, fig. 10). As molds, C. spengleri is relatively common in the Holey Land limestone at the Griffin Brothers pit. but the preservation is poor and most specimens are fragmen- tary. Complete specimens such as the holotype, however, have only been collected in the unconsolidated marly facies of the Holey Land Unit in northern Dade County. Cypraea spengleri is most similar to C. (Macrocy- praea] cervus Linnaeus, 1771 from the Carolinian Prov- ince and, based on its similar shape and size, is probably the direct ancestor of that well known Recent species. The main difference between the two cowries, however, is seen in the form of the apertural teeth, particularly those of the columella; in C. cervus, the columellar teeth are slender and elongated, extending well onto the base of the shell (figure 7), while in C. spengleri. the colu- mellar teeth are short and coarse and do not extend onto the base but. instead, terminate along the edge of the columella (figure 6). Likewise, the labial teeth of C cer- vus are finer and more elongated than those of C. spen- gleri. and also extend farther onto the shell base. The number of apertural teeth also differs between the two species, with C. cervus having more teeth (average 37 columellar. 43 labial) than C. spengleri (average 33 col- umellar, 40 labial).
Pseudozonaria Schilder. 1927
Cypraea (Pseudozonaria) portelli n.sp. (figures 8. 9. 10)
Material examined: HOLOTYPE — Length 25 mm, dredged irom 15 m depth in Griffin Brothers pit, 10 km west of US Highwav 27, at Broward-Palm Beach Countv line, Florida, UF 28985; PARATYPE— Length 25 mm, from 20 m depth in Capeletti Brothers pit #11, 7 km west of Florida Turnpike, northeastern Dade County-, Florida, Petuch collection.
Description: Shell average size for subgenus, oval in outline, dorsoventralK flattened; beaks yvell developed, projecting; margins thickened, sharply angulate; base slightly rounded; spire region shalloyvly indented; ap- erture narroyv, slightly arcuate; teeth blunt and coarse, numbering 15 along columella and 19 along lip (of ho-
THE NAUTILUS, Vol. 104, No. 3
Figures 1-10. New Melongenids and Cypraeids from the "Holey Land Unit" of the Bermont Formation 1. Melongena (Mic- cosukea) cijnthiae n.sp . dorsal view of paratype, length .5.5 mm; 2. Melongena (Miccosuke(2)cynthiae n sp., ventral view of holotype, length 38 mm; 3, 4. Melongena (Miccosukea) holeylaiulica n.sp., dorsal and ventral views of holot\ pe, length .35 mm; 5. 6. Cypraea {Macrocypraea) spengleri n.sp., dorsal and ventral views of holotype, length 107 mm; 7. Cypraea (Macrocypraea) cervus Linnaeus, 1771, ventral view of 85 mm specimen, for comparison with C. (Macrocypraea) spengleri. 8, •). Cypraea (Pseiidozonaria) portelli n.sp., dorsal and ventral views of holotype, length 25 mm; 10. Cypraea {Pseiidozonaria) porlelli n sp., lateral view (left) of holotype.
E. J. Petuch, 1990
Page 99
lotype); color pattern (faintly preserved on holotype) composed of numerous, denseK -packed specklings, often fusing together to form longitudinal stripes, on the dor- sum and numerous evenly-spaced small spots on margins; anterior and posterior tips each with 2 large patches.
Etymology: Named for Mr. Roger Portell, Florida Mu- seum of Natural History, who collected the holotype.
Discussion: Cypraea portelli represents the first species of its subgenus to be found in the fossil record of the United States. Until now, Pseudozonaria was unknown in the Caloosahatchian Province (Miocene to Pleistocene S.E. United States and the Floridian Peninsula), and was thought to have been confined to the Gatunian Province (Miocene to Pleistocene Caribbean, northern South America, and western Central America) (Petuch, 1982; Vermeij & Petuch, 1986). In the Recent, the subgenus is represented by three species from the Panamic Province of the tropical western Americas; C. [Pseudozonaria) arobicula (Lamarck, 1811), C. (Pseudozonaria) nigro- punctata Gray, 1828, and C. (Pseudozonaria) robertsi (Hidalgo, 1906). Of the three living species, C. (Pseu- dozonaria) portelli is most similar to C. robertsi, being the same size and having the same type of apertural teeth, shape and form of the aperture, and color pattern. The new species differs from C. robertsi, however, in having a broader, more rounded outline and in having angled, thickened margins.
In the fossil record of the Gatunian Province of the Caribbean basin, C. portelli is most similar to C. ray- mondrobertsi bowdenensis (Pilsbry, 1922) from the Plio- cene of Jamaica and the Dominican Republic. Both spe- cies share the same broad, oval shell outline and the same flattened appearance. The apertural teeth of C. raij- mondrobertsi bowdenensis, however, are proportionally much larger and better developed than those of C. por- telli, and extend much farther across the base of the shell. Cypraea portelli was probably the last Pseudozo- naria to live in the Atlantic.
Buccinacea
Melongenidae
Melongeninae
Melongena Schumacher, 1817
Miccosukea new subgenus
Diagnosis: Shells average-sized for genus, but more elongated and fusiform, generally resembling Fasciola- ria species in outline; shoulders, especialK' those of body whorls, rounded, without prominent spines or Dutings; shoulders of whorls ornamented with low, rounded knobs or evenly-spaced low, rounded axial ribs; spires and body whorls both heavily sculptured with numerous strong spiral cords; spiral cords finer and more numerous on siphonal canals; siphonal canals very well-developed, elongated; siphonal canals of some species well-differ- entiated from body whorl, narrow, giving shells appear- ance of small Pugilina or Busycon species; aperture wide, flaring, oval in shape; spire height and development vari-
able within subgenus, with some species having elevated, scalariform spires and others having low, slightly-stepped spires; sutures slightly impressed, smooth, without fine fimbriations or crenulations.
Type species: Melongena (Miccosukea) cynthiae new species, described here. Lower beds ("Holey Land Unit") of Bermont Formation, Aftonian Stage, Pleistocene, Palm Beach County, Florida (figures 1, 2).
Other species in Miccosukea: Melongena (Miccosukea ) holeylandica new species, described here. Lower beds ("Holey Land Unit") of Bermont Formation, Aftonian Stage, Pleistocene, Palm Beach County (figures 3, 4); Melongena (Miccosukea) sp., fragmentary, Bermont Formation, Aftonian (Yarmouth?) Stage, Pleistocene, Dade County, Florida.
Etymology: The new subgenus honors the Miccosukea Seminole Tribe of the Everglades.
Discussion: The new subgenus represents a separate evolutionary line off the Melongena Schumacher, 1817 (sensu stricto) stock, and appears to have been endemic to southern Florida. This local radiation differs from classic Melongena species in containing smaller, more fusiform shells with better-developed and more elon- gated siphonal canals, and in lacking sutural fimbriations and large shoulder spines. Miccosukea also differs from the subgenus Rexmela Olsson and Harbison, 1953 in being more fusiform in shape, in having much better developed siphonal canals, in lacking large shoulder spines, and in lacking the "collar" of fimbriations bor- dering the suture.
At several Bermont localities, Melongena (Miccosu- kea) species and Melongena (Rexnuda) species, such as M. (Rexmela) bispinosa (Philippi, 1844), occur together and show that the two subgenera were sympatric.
Melongena (Miccosukea) cynthiae new species
(figures 1, 2)
Material examined: HOLOTYPE — Length 38 mm, dredged from 15 m depth in Griffin Brothers pit, 10 km west of US Highway 27, at Broward-Palm Beach Countv line, Florida, USNM 448813; PARATYPES— Length 55 mm (incomplete), same locality as holotype, FAU 322 (figure 1); lengths 41 and 52 mm, same locality as ho- lotype, FAU 323; length 64 mm, same locality as holo- type, Petuch collection.
Description: General shell shape and form as for sub- genus; spire protracted, scalariform; spire v\ horls convex; suture impressed; spire, body whorl, and siphonal canal heavily sculptured with numerous large, evenly-spaced spiral cords; smaller secondary cords present between large primary cords.
Etymology: Named for Mrs. C\iithia Mischler, De- partment of Geology, Florida Atlantic L'niversitv .
Discussion: Melongena cynthiae, type of the new sub- genus, more closely resembles a small Pugilina Schu-
Page 100
THE NAUTILUS, Vol. 104, No. 3
machcr, 1817 species than it does other western Atlantic melongenids. UnUke Pugilina species, M. cynthiae has a distinctly rounded shoulder on the body whorl, rounded and convex spire whorls, and an impressed suture. In having a protracted, scalariform spire, the new species somewhat resembles high-spired forms of Melongena (Rexmela) corona (Gmelin, 1791), such asaltispira Pils- bry and Vanatta, 1934. Melongena cynthiae differs from these high-spired forms, however, in having a much more elongated body whorl and in having a much better de- veloped, and longer, siphonal canal. Being in Miccusii- kea, M. cynthiae also lacks the open shoulder spines and fimbriated sutures of Rcxnicla species.
The new species is also similar to the stratigraphically higher Melongena (Miccosukea) holeylandica n.sp. (fig- ures 3, 4), but differs in having a much higher, scalari- form spire, in having a longer siphonal canal, and in being more heavily sculptured with strong spiral cords. A large, undescribed Miccosukea species has also been collected, although only as fragments, in the uppermost beds of the Bermont Formation in the Capeletti Brothers pit. This un-named species also has a high, scalariform spire, but has a smoother, less sculptured shell. The "Mel- ongenid-new genus, new species" that I previously il- lustrated (Petuch, 1988: plate 24, figs. 1, 2) is M. cynthiae.
Melongena (Miccosukea) holeylandica new species (figures 3, 4)
Material examined: HOLOTYPE — Length 35 mm, dredged from 12 m depth in Griffin Brothers pit, 10 km west of US Highway 27, at Broward-Palm Beach County line, Florida, USNM 448814; PARATYPES— Lengths 48, 51, and 55 mm, same locality as holotype, FAU 324; length 52 mm, same locality as holotype, Petuch collec- tion.
Description: General shell shape and form as for sub- genus; spire low, rounded, slightly dome-shaped; sub- sutural area raised to form large, rounded spiral cord; subsutural cord producing minutely canaliculate suture; spire, body whorl, and siphonal canal sculptured with low, faint spiral cords; shoulder of body whorl orna- mented with scattered small, low knobs; siphonal canal broad.
Etymology: Named for the area adjacent to the type locality, the Holey Land Wildlife Refuge.
Discussion: The similarities and differences between Melongena holeylandica and the only other named Mic- cosukea species, M cynthiae, are discn.s.sed under the preceding description. The "Melongenid-nev\ genus, new species" that I previously illustrated (Petuch, 1988: plate 24, figs. 5, 6) is M holeylandica.
Volutacea
Volutidac
Scaphellin; •
Scaphella .'■ u ;rvn, 1832
Scaphella seminole new species (figures 18, 19, 20, 21)
Material examined: HOLOTYPE — Length 52 mm, dredged from 20 m depth in Capeletti Brothers pit #11, 7 km west of Florida Turnpike, due west of Hialeah, northeastern Dade County, Florida, CM 35729; P.\R,\- TYPES — Length 53 mm, same locality as holotype, CM 35730 (figures 20, 21); lengths 54, 55, and 56 mm, same locality as holotype, FAU 325; lengths 55, 56 mm, same locality as holotype, Petuch collection.
Description: Shell small for genus, fusiform, with rounded, sloping shoulder; spire proportionally low, with sloping whorls; top of shoulder marked with faintly in- cised, shallow furrow; area between suture and shoulder furrow producing wide, faintK raised subsutural band; protoconch proportionalK large, rounded, domelike, with rounded calcarella; first 2 postnuclear whorls heavily sculptured w ith numerous, evenly-spaced, large axial ribs; axial ribs overlaid with numerous fine spiral threads, producing slightly cancellate appearance; columella with 4 large plications; color pattern, when preserved, com- posed of 7-9 rows of large, evenly-spaced rectangular checkers.
Etymology: Named for the Seminole Indian Tribe of the Everglades region.
Discussion: Scaphella seminole is the smallest of the known fossil Scaphella species, with the average length of the type lot (all adult specimens with thickened, pos- teriorly-Daring lips) being only around 54 mm. The new- species is similar to the late Pliocene-earK Pleistocene Caloosahatchee Formation S. floridana (.Heilprin, 1886), but differs in having a much smaller, stumpier shell with a much lower, unprotracted spire. The axial ribbing on the postnuclear whorls of S. floridana is also coarser and better developed than that of S. seminole and extends onto the third whorl.
Conacea Conidae Conus Linnaeus, 1758
Conus capelettii new species (figures 11, 12, 13)
Material examined: HOLOTYPE — Length 38 mm, dredged from 20 m depth in Capeletti Brothers pit #11, 7 km west of F'lorida Turnpike, due west of Hialeah, northeastern Dade C:ount\, Florida, CM 35731; PARA- TYPES— Length 33 mm, same localit\ as holot\ pe, CM 35732 (figure 13); lengths 36, 39, 41, and 42 mm, same localits as holotype, Petuch collection.
Description: Shell slender, elongateK subpyriform, bi- coiiic; shoulder sharply angled, carinated; spire very pro- tracted, scalariform; body whorl and spire smooth, with silky texture; anterior end encircled with 8-10 deep, evenly-spaced grooves; aperture narrow, widening slightly
E. J^ Petuch, 1990
Page 101
Figures 11-21. New Conids and Volutids from the "Holey Land Unit" of the Bermont Formation. 11, 12. Conus capelettii n.sp., dorsal and ventral views of holotype, length 38 mm; 13. Conus capelettii n.sp, dorsal view of paratspe, length 33 mm: 14, 15. Conus griffini n.sp., dorsal and ventral views of holotype, length 15 mm; 16. 17. Conus lemoni n.sp., dorsal and ventral views of holotype, length 56 mm; 18, 19. Scaphella seminole n.sp., dorsal and ventral views of holotype, length 52 mm; 20, 21. Scaphella Seminole n.sp., dorsal and ventral views of parat\pe, length 53 mm.
Page 102
THE NAUTILUS, Vol. 104, No. 3
Figure 22. Detail of a fossiliferoiis liincstone block from the lia.sal beds ("Holey Land Unit") of the Bermont Formation. This block was dredged from 15 rn depth in the (iriffin Brothers pit on the Palm Beach-Broward County line in the central Everglades Basin. The lucinids on the left and lower left are approximately 60 mm in diameter
toward anterior end; color pattern, ulieii preserved, com- posed of wide longitudinal flaiiumiles and zig-zags.
Etymology: Named for Mr. Ronald Capeletti, of Ca- peletti Brothers, Inc., Hialeah, Florida, in thanks for al- lowing me to collect large suites of Bermont material on his property.
Discussion: Conns capelettii has the highest, most sca- lariform spire of any cone shell known from the Plio- Pleistocene fo.ssil record of Florida. Based on shell shape, size, and spire form, the new species appears to be more closely relatetl to Conns scalaris Valenciennes, 1832 from the Recent western coast of Mexico than to other western Atlantic cone shells. C.'of!(/.s capelettii differs from C.
E. J. Petuch, 1990
Page 103
scalaris, however, in having a proportionally shorter body whorl with a distinctly more pyriform shape. The new Berniont species is also similar in shape to some slender morphs of the Recent Carolinian Province C. floridanus Gabb, 1868, but differs primarily in having a sharper, more carinated shoulder and in having a much higher, scalariform spire.
Conus griffini new species (figures 14, 15)
Material examined: HOLOTYPE — Length 15 mm, dredged from 15 m depth in North New River Canal, along US Highway 27, 30 km south of South Bav. Palm Beach C:ount> , Florida, CM 35733; PARATYPE— Length 18 mm, dredged from 15 m depth in Griffin Brothers pit, 10 km west of US Highway 27, at Broward-Palm Beach County line, Florida, Petuch collection.
Description: Shell small for genus, slender, straight- sided; shoulder sharply angled, carinated; spire low and flattened; body whorl smooth and shiny; anterior tip en- circled with 8-10 low, rounded cords; aperture narrow; protoconch mammillate, projecting above spire line; col- or pattern, when preser\ed, composed of single row of small spots around midbod\
Etymology: Named for Mr. Howard A. ("Andy") Grif- fin, Jr., Davy, Florida, in thanks for allowing me to collect on his propert) over the last eight years.
Discussion: Conus griffini is the first member of the C. magellanicus Hwass, 1792 species complex to be found in the fossil record of continental North America. In the Recent, this complex of small cones is confined to shallow water, coral reef areas of the West Indies, Bahamas, and Caribbean Basin. The new Bermont species is most sim- ilar to the Recent C. kalafuti DaMotta, 1987 from Roatan Is., Honduras, and both cones have the same small size, flat spire, projecting nipple-like protoconch, and color pattern composed of a checkered midbody band. Conus griffini differs from C. kalafuti, however, in having a more slender, straight-sided shell and in having stronger spiral cords around the anterior tip. Otherwise, the two species are very similar, and C. griffini is most probably the ancestor of the Honduran C. kalafuti.
Previously (Petuch, 1988: plate 23, fig. 2), 1 had illus- trated and referred to this new Bermont cone as "Conus cf. eversoni Petuch, 1987." That species, which is also related to C. kalafuti and is also from Roatan Is., Hon- duras, has a larger and more elongated shell than C. griffini. The protoconch of C. griffini is also proportion- ally larger than that of C. eversoni and is more promi- nentlv mammillate.
Conus lemoni new species (figures 16, 17)
Material examined: HOLOTYPE— Length 56 mm, dredged from 15 m depth in Griffin Brothers pit, 10 km
west of US Highway 27, at Broward-Palm Beach County line, Florida, CM 35734; PARATYPES— Length 49 mm, same localit>- as holotype, CM 357.35; lengths 37, 45, 48^ and 68 mm, same locality as holotype, FAU 326; length 65 mm, dredged from 20 m depth in Capeletti Brothers pit #11, 7 km west of Florida Turnpike, due west of Hialeah, northeastern Dade County, Florida, Petuch col- lection.
Description: Shell broad, heavy, with wide shoulder; shoulder angled, with rounded edge; spire low, flattened, with early whorls projecting above later whorls; suture indented; spire w liorls distinct!) canaliculate; bodv whorl heavily sculptured v\ ith numerous, closely-packed, large spiral cords; aperture narrow; color pattern, when pre- served, composed of numerous rows of small spots, often arranged in bands, and scattered large axial flammules that often coalesce to form longitudinal stripes; spire marked with evenly-spaced crescent-shaped flammules.
Etymology: Named for Dr. Roy Lemon, Department of Geology, Florida Atlantic University.
Discussion: Conus lemoni is a new member of the Co- nus spurius, 1791 species complex of the Pliocene-to- Recent Caribbean and Floridian regions. Morphologi- cally, the new Bermont species combines the shell char- acters of tw o Recent species, C. spurius atlanticus C:lench, 1942 and C. lorenzianus Dillwyn, 1817. In having a broad shell shape, rounded shoulder edge, and low spire, C. lemoni resembles the Carolinian C. spurius atlanti- cus. On the other hand, in being hea\ il\ sculptured \\ ith closeK-packed spiral cords and in having a flammulated color pattern, the new Bermont cone resembles the south- western Caribbean C. lorenzianus. It is possible that C. lemoni is ancestral to both closely-related species.
In the Florida fossil record, C. lemoni is similar to several undescribed subspecies of C. spurius from the upper beds of the Bermont Formation and the overlying Fort Thompson Formation (late Pleistocene). The new Holey Land species differs from the younger C. spurius subspecies, however, in having distinctly canaliculate spire whorls and in being heavik' sculptured with spiral cords.
ACKNOWLEDGEMENTS
I thank Mr. John Spengler, Lantana, Florida, for assisting me in the collection of Bermont fossils, and Mr. Howard ("And\") Griffin, Jr., and Mr. Ronald Capeletti for al- lowing me to collect on their propert) . Special thanks to Mrs. Cynthia Mischler for patientK t\ping the manu- script.
LITERATURE CITED
DuBar, J R 1974 Suinmar\ ot tlie N'eogene stratigraphy of southern Florida In: Oaks, R. Q. and J R DuBar (eds.) Post-Miocene stratigraph) , Central and Southern .Atlantic Coastal Plain. Utah State University Press, p. 206-231.
Hoerle, S, E 1970 Mollusca of the "Cllades" unit of .southern
Page 104
THE NAUTILUS, Vol. 104, No. 3
Florida: Part II. List of Molluscan species from the Belle Glade Rock Pit, Palm Beach C:oiint\ , Florida. Tiilane Stud- ies in Geology and Paleontology 8(2):56-68.
McGinty, T. L. 1970. Mollusca of the "Glades" unit of south- ern Florida: Part I. Introduction and observations. Tulane Studies in Geology and Paleontology 8(2):53-56.
Petuch, E. J. 1982. Geographical heterochrony: contempo- raneous coexistence of Neogene and Recent molluscan faunas in the .Americas. Palaeogeography , Palaeoclima- tology, and Palaeoecology 37:277-312.
Petuch, E. J. 1988. Neogene history of tropical .American mollusks. The Coastal Education and Research Founda- tion, Charlottesville, Virginia. 217 p.
Petuch, E. J. 1989. New species of Malea (Gastropoda Ton- nidae) from the Pleistocene of southern Florida. The Nau- tilus 103(3):92-95.
\ ernieij, G J. and E. J Petuch 1986. Differential extinction in tropical .American molluscs: endemism, architecture, and the Panama Land Bridge. Malacologia 27(1):29-41.
\okes, E. H. 1968. Cenozoic Muricidae of the Western .At- lantic Region. Fart IV — Hexaplex and Murexiella. Tulane Studies in Geology 6(3):85-126.
N'okes, E. H. 1976. Cenozoic Muricidae of the Western .At- lantic Region. Part VII — Calotropbon and Attiliosa. Tu- lane Studies in Geology and Paleontology 12(3):101-132.
Vokes, E. H. 1984. A new species of Turbinella (Mollusca: Gastropoda) from the Pliocene of Mexico, with a revision of the geologic history of the line. Tulane Studies in Ge- ology and Paleontology 18(2):47-52.
THE NAUTILUS 104(3): 105-107, 1990
Page 105
Micropilina tangaroa, a New Monoplacophoran (Mollusca) from Northern New Zealand
B. A. Marshall
National Museum of New Zealand
Box 467
Wellington, New Zealand
ABSTRACT
Micropilina tangaroa n.sp., based on a single shell from the Three Kings Rise, northern New Zealand, is the first record of the class Monoplacophora from the western Pacific.
Key words: Monoplacophora; New Zealand; Micropilina.
the multiple muscle attachment scars characteristic of many species of the class (figure 3) (Lemche & Wing- strand, 1959; Wingstrand, 1985), The class name is gen- erally credited to Wenz (in Knight, 1952), but, as indi- cated by Waren (1988), it was first introduced bv Odhner {in Wenz, 1940).
INTRODUCTION
Since the discovery of Neopilina galathea in 1952 (Lemche, 1957), 14 Recent species have been added to the class Monoplacophora (Lemche, 1957; Clarke & Men- zies, 1959; Menzies & Layton, 1963; Tebble, 1967; Men- zies, 1968; Rokop, 1972; McLean, 1979; Moskalev et al, 1983; Bouchet et al, 1983; Waren, 1988, 1989; Waren & Bouchet, 1990). These species are based on material from off Hawaii, the eastern Pacific margin, the western and northern Atlantic, and the Gulf of Aden. The present record extends the range to the southwestern Pacific (fig- ure 1). Recent monoplacophorans are mainly confined to bathyal and abyssal depths, though one species lives at 174-388 m depth off southern California (McLean, 1979). Monoplacophoran morphology and anatomy have been discussed in detail by Lemche and Wingstrand (1959) and Wingstrand (1985), while Menzies e< al. (1959) and Tendal (1985) have discussed their ecology and diet.
Class Monoplacophora Odhner in Wenz, 1940
Genus Micropilina Waren, 1989:2
Type species: Micropilina minuta Waren, 1989, by original designation; Recent, northern Atlantic.
Remarks: Suprageneric classification of the Monopla- cophora has been drastically modified by Moskalev et al. (1983) and Starobogatov and Moskalev (1987). These authors placed the 11 Recent species then known into six families and three superfamilies. Unfortunately the anatomy of Micropilina is unknown, so it cannot be placed in this hierarchial framework. Despite the lack of supportive anatomical data, Micropilina species are undoubtedly monoplacophorans, since their shells exliibit
Figure 1. Map of New Zealand showing t\pe localit\' (star) for Micropilina tangaroa new species. 200 and 1000 meter contours indicated
\
Lll
/w-
|
¥ |
|
|
/ |
|
|
(f-- |
V ■ J? |
|
y. |
f . |
^
•
'-P
Figures 2-5. Micwpilina tangawa new species. 2. Lett lateral, '.\. ventral, and l. dorsal views of holotype (length = L50 mm) 5. Detail of teleoconcfi sculpture (800 x ).
B. A. Marshall, 1990
Page 107
Micropilina tangaroa new species (figures 2-5)
Description: Shell {holot\pe) 1.50 mm long, thin, strongK arched capuliform; apertural margin regularly (uate, concave from side to side; rounded apex projecting slightly beyond anterior apertural margin, opaque white. Shell wall apparently lamellar throughout, presumably arganonite. Apical area convex, 0.17 mm long, defined bv fine concentric ridge, surface slightly etched. Exterior surface at 0.17-0.30 mm shell length essentially smooth apart from few, fine raised concentric growth lines. Thereafter sculptured with strong concentric ridges and finer radial riblets. Concentric ridges close, sharply de- fined, broader than high, summits weakK' convex, inter- spaces about half width of each ridge, weaker and less sharply defined beside apertural margin. Radial riblets confined to interspaces of concentric ridges, rounded, interspaces slightly narrower than each riblet, each riblet about as wide as interspace of each concentric ridge. Interior surface encircled by complex series of muscle attachment scars, of which at least 15 pairs are discern- able, through precise number of muscle attachment points uncertain, especially over anterior half. Animal un- known.
Type material: Holotype New Zealand Oceanographic Institute, Wellington H.555 (length 1.50 mm, w idth 0.88 mm, height 0.50 mm).
Type locality: (Figure 1) Station U.602, 31°30.7'S, 172°49.8'E, northern Three Kings Rise, northern New- Zealand, dead 1,216-1,385 m, rocky substratum with pumice, carbonate sand and shell, February 9, 1988, R. V. Rapuhia.
Etymology: The species is named for the Maori sea god Tangaroa.
Discussion: Compared with the north Atlantic species Micropilina miniita Waren, 1989, which it most resem- bles, M. tangaroa differs in being larger (length 1.50 mm compared with 1.06 mm), and in having concentric ridg- es that are much larger both in actual size and in size relative to the size of the radial riblets. Judging from the increasing curvature of the posterior and lateral slopes and the change (presumably senescent) in sculpture be- side the apertural margin, the holotype of M. tangaroa is evidently an adult. Apical pits recorded by Waren (1988, 1989) were not observed in the present specimen, which is long dead, locally stained by manganese de- position, and slightly etched.
ACKNOWLEDGEMENTS
1 thank curatorial staff at New Zealand Oceanographic Institute, Wellington, for access to sediment samples that yielded the monoplacophoran, New Zealand Geological Survey, Lower Hutt, for scanning electron microscopy, Mark Strange for photographic printing and Kathleen Ryan for word processing.
LITERATURE CITED
Bouchet, P., J H McLean, and A. Waren. 1983. .\lonopla- copliorans in the North .■\tlantic. Oeeanologica Acta 6'.117- 118.
Clarke, A. H, and R. J. Menzies. 19.59, Seopilina (Vema) ewingi, a second new living species of tlie Paleozoic class Monoplacophora. Science 129:1026-1027.
Knight, J, B. 1952. Primitive fossil gastropods and their bear- ing on gastropod classification. Smithsonian Miscellaneous Collections 117(13):l-56.
Lemche, H, 1957 .\ new living deep .sea mollusc of the Cambro-Devonian class Monoplacophora. Nature, London 179:41.3-416.
Lemche, H. and K G, Wingstrand. 19.59. The anatomy of Neopilina galatheae Lemche, 1957. Galathea Report 3:9- 71.
McLean, J. H. 1979. A new monoplacophoran limpet from the continental shelf off southern California. Contributions in Science. Natural Historv Museum of Los Angeles Coun- ty 307:1-19.
Menzies, R. J. 1968. New species of Ncopi/ina of the Cambro- Devonian class Monoplacophora from the Mihie-Edwards Deep of the Peru-Chile Trench, R/\' ,\nton Bruun Pro- ceedings of the Symposium on Mollusca of the Marine Biological .'Association of India 3:1-19.
Menzies, R. J. and W. Layton. 1963. A new species of mono- placophoran mollusc, Neopilina (Neopilina) veleronis from the slope of the Cedros Trench, Mexico. Annals and Mag- azine of Natural History ser. 13, 5:401-406.
Menzies, R. J., M. Ewing, J, L. Worzel, and A. H. C;larke. 1959. Ecologv of the Recent Monoplacophora. Oikos 10:168- 182.
Moskalev, L. 1., Y. I Starobogatov, and Z. A. Filatova. 1983. New data on the abyssal Monoplacophora from the Pacific and South Atlantic Oceans. Zoologicheski Zhurnal 112: 981-995.
Rokop, R. J. 1972. \ new species of monoplacophoran from the abyssal North Pacific Veliger 15:91-95.
Starobogatov, Y. I. and L. I Moskalev. 1987. Systematics of the Monoplacophora. In: Starobogatov, Y. I., A. N. Goli- kov, and I. M. Likarev (eds.). Molluscs, results and per- spectives of investigation. USSR, .\cadeniy of Sciences, Zoological Institute, p. 7-11. Eight meeting on the inves- tigation of molluscs.
Tebble, N. 1967. A Neopilina from the Gulf of .lAden. Nature, London 215:663-664.
Tendel, O. S. 1985. Xenophyophores (Protozoa, Sarcodina) in the diet of Neopilina galatheae (Mollusca, Monopla- cophora). Galathea Report 1695-98.
Waren, A. 1988. Neopilina goesi, a new Caribbean mono- placophoran mollusk dredged in 1869. Proceedings of the Biological Society of Washington 101:671-681
Waren, A. 1989. New and little known Mollusca from Iceland. Sarsia 74:1-28.
Waren, A. and P Bouchet. 1990. Laevipilina rolani, a new monoplacophoran from off southwestern Europe. Journal of Molluscan Studies 56(3):449-453
Wenz, W, 1940 Ursprung und friihe Stammesgeschichte der Gastropoden. Archiv fiir Molluskenkvmde 72:1-10.
Wingstrand. K. G 1985. On the anatom\ and relationships of Recent Monoplacophora. Galathea Report 16:7-94.
THE NAUTILUS 104(3): 108-1 10, 1990
Page 108
Addenda to ^'Distorsio ridens (Reeve, 1844): A Synonym of Distorsio clathrata (Lamarck, 1816) (Gastropoda: Personidae)"
^ illiam K. Emerson ^ alter E. Sage. Ill
Department of Imertebrates American Museum of Natural History New York, NY 10024-5192 USA
We are indebted to David Freeman of Cape Town, South Africa for calling our attention (in litt.. June 6, 1990) to an error in our recent paper pertaining to the identity of Distorsio ridens (Reeve, 1844) (Emerson and Sage, 1990). Through an unfortunate oversight, a photograph of the apertural view of a paralectotype of D. ridens [British Museum (Natural History) 1967630, = D. clath- rata (Lamarck, 1816)], which was correctly cited and illustrated in figure 6, was inadvertently substituted for figure 2. Figure 2 was erroneously labeled the apertural view of the lectotype of D. ridens [American Museum Natural History (AMNH) 6369, = D. clathrata].
The apertural view of the lectotype was previously illustrated by Lewis (1972:45, figure 48) and an enlarge- ment of the aperture of the lectotype was provided in our paper (Emerson and Sage, 1990, figure 15). To cor- rect our error, the entire view of the ventral aspect of the lectotype is given herein to compare with Reeves (1844, pi. 12, sp. 46) original figure of Triton ridens [= Distorsio clathrata]. See figures 1, 2, herein.
Reference also should be made here to the two un- identified species of Distorsio trawled in 400 m off Cape Gardafui (Ras Asir), Somalia that were under study by us at the time we were preparing our review of D. ridens (Emerson and Sage, 1990:131). One of these was de- scribed on March 31, 1990 as Distorsio somalica Parth from "North of Mogadishou, dredged in deep water" (Parth, 1990, figure 1; herein figures 9-12). Parth's newly described taxon has some morphological characters that are reminiscent of Distorsio decipiens (Reeve, 1844) and D. reticularis (Linne, 1758) [= D. reticulata Roding 1798, fide Beu, 1987:314]. Distorsio somalica has a larger, nar- rower shell with more prominent labial teeth (as well as other differing sculptural features) than that of D. de- cipiens. Distorsio somalica resembles somewhat the gen- eral shape of D. reticularis, but has a narrower shell with
weaker sculpture and more prominent labial teeth. In the past D. reticularis has been confused with D. de- cipiens (see Springsteen, 1985). Parth (1990:1), however, compared the type specimens of D. somalica with D. perdistorta Fulton, 1938.
The other Somalian specimens we examined are ap- parentK referable to D. perdistorta. a wide-ranging Indo- West Pacific species with populations also in the eastern and western Atlantic Ocean (Beu, 1985:62). Our speci- mens of D. perdistorta from Somalia differ from the shells of the western-Pacific populations b\ having a wid- er, more inflated shell, with the expanded outer lip com- monly colored with tan rays and the parietal shield cov- ered (in all 4 of the specimens examined) by a brightly colored tan glaze (herein figures 3-6). The "typical" Indo- Pacific specimens of D. perdistorta. which have a nar- rower, less inflated, but a more distorted shell with a whitish parietal shield, however, are also known from off Madagascar in 300-340 meters [N. of Nossi Be, 12°43'S, 48°15'E, Academy Natural Sciences of Philadelphia 352156 (ANSP)], as reported by Lewis (1972:29). The presence of both of these forms in the Indian Ocean suggests that they are likely only morphs of D. perdis- torta. Compare figures 3-6 with figures 7, 8. Distorsio reticularis (Linne, 1758) is also known to occur in the Indian Ocean, as noted by Parth (1990).
ACKNOWLEDGEMENTS
In addition to the courtesy extended by Mr. Freeman, we are indebted to Mr. John Bernard of Crossville, TN and to Dr. Gary Rosenberg of the Philadelphia .-Kcadem}- of Sciences, PA for kindK- pro\iding us w ith the Somalian and Madagascan specimens of Distorsio. respectiveK , for study and report. Dr. Alan Beu of the New Zealand Geological Survey, Lower Hutt generously contributed
Figures 1, 2. Distorsio ridens (Reeve. 1844). 1. Copy of original illustration of Triton ridens Reeve. 2. Lectotype of Triton ridens Reeve (AMNH 6369) Figures 3-8. Distorsio perdistorta Fulton, 1938. 3-6. Off Cape Gardafui, Somalia, ex-John Bernard Collection (3, 4. AMNH 232148: H. 6. AMNH 232147). 7, 8. North of Nossi Be, Madagascar (ANSP 352156) Figures 9-12. Distorsio somalica Parth, 1990, same locality data as in figures 3-6 (9, 10. AMNH 232149; 11. 12. AMNH 232150) All figures xl.
W. K. Emerson and W. E. Sage, 1990
Page 109
Page 110
THE NAUTILUS, Vol. 104, No. 3
additional data and expressed his views on the taxonomic status of the specimens from Somalia. We also thank Mr. Andrew Modell and Ms. Stephanie Grooms of the .\merican Museum of Natural History who undertook the photography and the word-processing of the manu- script, respectively.
LITERATURE CITED
Beu, A. G. 1985. A classification and catalogue of living world Ranellidae (= Cymatium and Bursidae). American Con- chologist (Bulletin Conchologists of America) 13(4):.55-66.
Beu, A. G. 1987 ["1986"]. Taxonomy of gastropods of the families Ranellidae (=Cymatiidae) and Bursidae. Part 2. Descriptions of 14 new modern Indo-West Pacific species and subspecies, with revisions of related taxa. New Zealand Journal of Zoology 12(3):273-355 [published January 28, 1987, teste BeuJ
Emerson, W. K, and VV. E, Sage, III. 1990, Distorsio ridens (Reeve, 1844); a synonym of Distorsio clathrata (Lamarck, 1816) (Gastropoda: Personidae). The Nautilus 103(4): 131- 135.
Fulton, H C. 1938. Descriptions and figures of new Japanese
marine shells. Proceedings of the Malacological Societ\ of
London 23(l):55-57. Lewis, H. 1972. Notes on the genus Distorsio (Cymatiidae)
with descriptions of new species. The Nautilus 86(2-4):
27-50. Linne, C. von. 1758. Systema naturae per regna tria naturae.
Editio decima, reformata. Stockholm 11-824 Parth, M, 1990. Distorsio somalica. spec, nov., ein neue Art.
aus Somalia (Gastropoda. Ranellidae). Spixiana (Miinchen)
13(l):l-3.
Reeve, L. A. 1844. Monograph of the genus Triton. Con- chologia Iconica: or illustrations of the shells of molluscous animals. Reeve Brothers, London, 2, Triton text and 20 pis. [T. ridens, sp. 44, pi. 12, May 1844; T. decipiens, sp. 102, pi. 20, August, 1844J
Roding, P. F. 1798. Museum Boltenianum , . pars secunda continens Conchylia. Hamburg, i-vii. 1-199 p.
Springsteen, F. J. 1985. Distorsio decipiens (Reeve, 1844), a valid biospecies rediscovered. Cartel Philippine Shell News (Manila) 7(5):3-5.
INSTRUCTIONS TO AUTHORS
THE NAUTILUS publishes papers on all aspects of the biology and systematics of mollusks. Manuscripts de- scribing original, unpublished research as well as review articles will be considered. Brief articles, not exceeding 1000 words, will be published as notes and do not re- quire an abstract. Notices of meetings and other items of interest to malacologists will appear in a news and notices section.
Manuscripts: Each original manuscript and accompa- nying illustrations should be submitted in triplicate. Text must be typed on one side of SVa x 11 inch white paper, double spaced throughout (including literature cited, ta- bles and figure captions), with at least 1 inch of margin on all sides. All pages must be numbered consecutively. If printed on a word processor, the right margin should be ragged rather than justified. Authors should follow the recommendations of the Council of Biology Editors Style Manual, which is available from the Council of Biology Editors, Inc., 9650 Rockville Pike, Bethesda, MD 20814, U.S.A. The first mention of a scientific name in the te.xt should be accompanied by the taxonomic au- thority, including year. Latin names and words to be printed in italics must be underlined; leave other indi- cations to the editor. Metric and Celsius units are to be used.
The sequence of sections should be: title page, abstract page, introduction, materials and methods, results, dis- cussion, acknowledgements, literature cited, tables, fig- ure captions, figures. The title page should include the title, author's name(s) and address(es). The abstract page should contain the title and abstract, which should sum- marize in 250 words or less the scope, main results and conclusions of the paper. The abstract may be followed by a maximum of 8 key words. All references cited in the text must appear in the literature cited section and vice versa. In the literature cited section, all authors must be fully identified and listed alphabetically. Follow a recent issue of THE NAUTILUS for bibliographic style, noting that journal titles must be unabbreviated. Infor- mation on plates and figures should be cited only if not included in the pagination. Tables must be numbered and each placed on a separate sheet. A brief legend must accompany each table. Captions for each group of illus- trations should be typed on a .separate sheet and include a key to all lettered labeling appearing in that group of illustrations.
All line drawings must be in black, high quality ink, clearly detailed and completely labeled. Photographs must be on glossy, high contrast paper. All figures are to be consecutively numbered (figs. 1, 2, 3, ... , NOT figs. la. lb, Ic, . . . NOR plate 1, fig. 1 . . .). Illustrations must be arranged in proportions that will conform with the width of a page (6% inches or 171 mm) or a column {'3Vi inches or 82 mm). The maximum size of a printed figure is 6% by 9 inches or 171 by 228 mm. All illus- trations must be fully cropped, mounted on a firm, white backing, numbered, labeled and camera ready. The au- thor's name, paper title and figure number(s) should ap- pear on the back. Original illustrations must be between one and two times the desired final size. It is the author's responsibility that the line weight and lettering are ap- propriate for the desired reduction. Original illustrations will be returned to the author if requested. Color illus- trations can be included at extra cost to the author.
Voucher Material: Deposition of type material in a recognized public museum is a requirement for publi- cation of papers in which new species are described. Deposition of representative voucher specimens in such institutions is strongly encouraged for all other types of research papers.
Processing of Manuscripts: Upon receipt, every manu- script is acknowledged and sent for critical review by at least two referees. These reviews serve as the basis for acceptance or rejection. Accepted manuscripts are re- turned to the author for consideration of the reviewers' comments. A finalized version of the manuscript is re- turned to the editor and sent to press. Two sets of proofs are sent to the author for correction. Changes other than typesetting errors will be charged to the author at cost. One set of corrected proofs should be sent to the editor as soon as possible. Authors with institutional, grant or other research support will be billed for page charges at the rate of $60.00 per printed page.
An order form for reprints will accompany the proofs. Reprints may be ordered through the editor.
Manuscripts, corrected proofs and correspondence re- garding editorial matters should be sent to: Dr. M.G. Harasewych, Editor, Division of Mollusks, NHB stop 118, National Museum of Natural History, Smithsonian In- stitution, Washington, DC 20560, USA.
THIS PUBLICATION IS PRINTED ON ACID-FREE PAPER.
rHE NAUTILUS
Volume 104, Number 4 December 13, 1990 ISSN 0028-1344
A quarterly devoted to malacology.
Maiiiie Biological Laboratory .. LIBRARY i
DEC 2 6 1990
Woods ^^■'■'«. Mass.
EDITOR-IN-CHIEF Dr. M G. Harasewych Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
ASSOCIATE EDITOR Dr. R. Tucker Abbott American Malacologists, Inc. P.O. Box 2255 Melbourne, FL 32902
CONSULTING EDITORS Dr. Riidigcr Bieler Department of Invertebrates Field Museum of Natural History Chicago, IL 60605
Dr. Robert T. Dillon, Jr. Department of Biology College of Charleston Charleston, SC 29424
Dr. William K. Emerson
Department of Living Invertebrates
The American Museum of Natural
History
New York, NY 10024
Mr. Samuel L. H. Fuller 1053 Mapleton Avenue Suffield, CT 06078
Dr. Robert Hershler Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
Dr. Richard S. Houbrick Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560
Mr. Richard I. Johnson Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, OH 43210
Dr. James H. McLean Department of Malacology Los Angeles County Museum of Natural History 900 Exposition Boulevard Los Angeles, CA 90007
Dr. Arthur S. Merrill % Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Ms. Paula M. Mikkelsen Harbor Branch Oceanographic Institution, Inc. Ft. Pierce, FL 33450
Dr. Donald R. Moore
Division of Marine Geology
and Geophysics
Rosenstiel School of Marine and
Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149
Mr. Richard E. Petit
P.O. Box 30
North Myrtle Beach, SC 29582
Dr. Edward J. Petuch Department of Geology Florida Atlantic University Boca Raton, FL 33431
Dr. David H. Stansbery Museum of Zoology The Ohio State University Columbus, OH 43210
Dr. Ruth D. Turner Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138
Dr. Geerat J. Vermeij Department of Geology University of California at Davis Davis, CA 95616
SUBSCRIPTION INFORMATION
The subscription rate per volume is US $25.00 for individuals, US $35.00 for institutions. Postage outside the United States is an additional US $4.00 for surface and US $12.00 for air mail. All orders should be accompanied b) payment and sent to: THE NAUTILUS, P.O. Box 7279, Silver Spring, MD 20907-7279, USA.
Change of address: Please inform the publisher of your new address at least 6 weeks in advance. All communications should include both old and new addresses (with zip codes) and stale the effective date.
THE NAUTILUS (ISSN 0028- 1344) is published quarterly by Trophon Corporation, 8911 Alton Parkway, Silver Spring, MD 20910.
Second Class postage paid at Silver Spring, MD and additional mailing offices.
POSTMASTER: Send address changes to: THE NAUTILUS P.O. Box 7279 Silver Spring, MD 20907-7279
THE €9 NAUTILUS
CONTENTS
Volume 104, Number 4
December IS. 1990
ISSN 0028-1344
Ronald W. Gilmer
Procymhiilia philiporum new species, with a discussion of
the genus Procymhtilia Meisenheimer, 1905 (Gastropoda:
Thecosomata) Ill
Studies on bathyal and abyssal Buccinidae (Gastropoda:
Neogastropoda): 1. Metula fiisiformis Clench and Aguayo,
1941 120
Bellascintilla parmaleeana new genus and species from
the tropical eastern Pacific, with a review of the other,
ventrally notched galeommatid genera (Bivalvia:
Gaieommatacea) 130
Malacology or Conchology? 145
M. G. Harasewych
C. Clifton Coney
Robert Robertson
Marine Biological Laboratory i LIBRARY
DEC 2 6 1990
Woods Hole, Mass.
SMITHSONIAN FUNDS FOR MALACOLOGY STUDENTS
The Division of Mollusks, Department of Invertebrate Zoology, National Museum of Natural Histor\ , Smithsonian Institution announces the availability of the Rosewater Fellow Award (up to $1,000) to be awarded to graduate students of systematic malacology. This award provides support for students conducting systematic studies of MoUusca (leading to publication) who require access to collections and libraries of the Division of Mollusks, National Museum of Natural History. Funds can be used for travel, subsistence, and research costs. Interested students should submit a succinct proposal (1-2 pages), including budget with indication of any matching funds, and a supporting letter from faculty advisor(s). Application deadline is January 31, 1991. Award(s) will be announced on April 15, 1991. Applications should be sent to:
Dr. R, S. Houbrick Division of Mollusks/NHB stop 118 National Museum of Natural History Smithsonian Institution Washington, DC 20560 USA
THE NAUTILUS 104(4):111-119, 1990
Page 111
Procijmbiilia philiporum New Species, with a
Discussion of the Genus Procymbulia Meisenheimer, 1905
(Gastropoda: Thecosomata)
Ronald W. Gilmer
Marine Science Division Harbor Branch Oceanographic
Institution 5600 Old Dixie Hwv Fort Pierce, FL 34946, USA
ABSTRACT
Procymbulia philiporum, new species, is described from sub- mersible collections in the Bahamas. This species retains a coiled shell but exhibits unique characters not known for other pseu- dothecosomes. It displays an extensive wingplate reminiscent of the famiK Cymbuliidae and encases its calcareous shell in a voluminous pseudoconch. Thus P philiporum displays key characters of both the Peraclididae and the Cymbuliidae. This species is most appropriately placed in the genus Procymbulia Meisenheimer, 1905, within the Family Peraclididae Tesch, 1913, to distinguish its transitional nature.
Key words: Pteropod; Thecosomata; Procymbulia, Peraclis.
INTRODUCTION
The genus Procymbulia Meisenheimer, 1905, was estab- hshed from observations of a single preserved specimen of the type species, P. valdiviae Meisenheimer, 1905, collected in the southern Indian Ocean. This genus is of special interest since even the damaged specimens thus far described display various morphological characters that relate it both to the shelled Peraclis Forbes, 1844, and to the shell-less cymbuliids. Thus it has been con- sidered a "missing link" (Meisenheimer, 1905; Tesch, 1913) between the shell-bearing genera of the Theco- somata and genera of the gelatinous pseudothecosomes (Cymbuliidae) which only possess a calcareous shell as larvae {e.g., Lalli and Gilmer, 1989). Approximately 64 specimens from various expeditions and usually from deep tows have been ascribed to this genus (Bonnevie, 1913; Massy, 1932; Tesch, 1913, 1946, 1948; Hubendick, 1951). No species of Procymbulia has ever been collected intact. Tesch (1948) obtained sufficient shell remnants from the Dana Expedition material to piece together the shape of what he considered to be the shell of P. valdiviae Meisenheimer, 1905. Although the shell differed from those of all previously described Peraclis species, Tesch concluded that the morphological differences displayed
by his specimens did not warrant the erection of a sep- arate transitional genus.
I here describe the first living, intact specimen of a Procymbulia species, which 1 ascribe to a new species. It was collected alive at 902 m with a manned sub- mersible. The animal exhibits key characters of both the Cymbuliidae and of the Peraclididae. These data war- rant the reinstatement of the genus Procymbulia Mei- senheimer, 1905.
MATERIALS AND METHODS
In the present description of the new Procymbulia spe- cies I have assumed that the shell and wingplate axes run anterior-posterior (table 1). This terminology was established by Lalli and Gilmer (1989) for correct ori- entation of the body of pseudothecosomes (Families: Per- aclididae, Cymbuliidae) to the shell and pseudoconch. Live pseudothecosomes are normally oriented with their ventral surface facing up. The proboscis and mouth are situated directly over the apex of the shell (in Peraclis) or over the blunt enlarged end of the pseudoconch (in cymbuliids). The median lobe of the wingplate is situated on the margin opposite the proboscis and lies directly over (ventral to) the pallial cavity opening. Thus the axis of the wingplate runs anterior-posterior in relation to the shell. This orientation is displayed by all live pseudoth- ecosomes (excluding Desmopterus Chun, 1889) and bears no resemblance to descriptions of preserved specimens of Peraclis or Procymbulia species {e.g., Meisenheimer, 1906; Tesch, 1948; Spoel, 1976). Preserved specimens are usually contracted and have the mantle cavity displaced laterally, towards the left or "dorsal" side of the shell in a manner that can resemble live specimens of the Li- macinidae (Euthecosomata). Thus coiled pseudotheco- somes are often erroneously considered analogous with the Limacinidae in regard to their body and shell ori- entation because of these preservation artifacts.
The single specimen was collected b\ the JOHNSON SEA-LINK I submersible using a 7.5 liter acrylic sampler
Page 112
THE NAUTILUS, Vol. 104, No. 4
I'able 1. Terminology used for orientation of soft part morphology of Procymbitlia by various authors compared to the present description.
|
Soft part |
Meisenheimer (1905) |
Tesch (1948) |
This paper |
|
W'ingpiate axis |
dorsoventral |
dorsoventral |
anterior-posterior |
|
Median lobe of wingplate |
ventral |
ventral |
anteroventral |
|
Proboscis |
dorsal |
dorsal |
posteroventral |
|
Tentacles |
dorsal |
dorsal |
posterior |
|
Pallial cavity |
ventral |
dorsal |
anteroventral |
|
Gill |
— |
ventral to right |
anterior on midline |
|
Anus |
right |
left |
anterior on right |
with lids at either end that move horizontally over the openings to assure gentle collection (Tietze and Clark, 1986). The sampler is sealed when closed so that there is no exchange of water during return to the surface. The specimen was immediately transferred to a 0.5 liter glass dish and maintained at 8 °C on board ship for observation and photography. Photographs were taken using a Zeiss Tessovar macrolens fitted with an Olympus OM-2 camera body and dark field illumination. All pho- tographs were taken with Kodak K-25 color slide film or Panatomic-X black and white film. The specimen was preserved in a 2% final solution of unbuffered glutaral- dehyde and transferred to 70% ethanol after two weeks. The specimens was not dissected and is deposited in the National Museum of Natural History, Smithsonian In- stitution (USNM 860550).
SYSTEMATICS
Family: Peraclididae Tesch, 1913 Genus: Procymbulia Meisenheimer, 1905
The original characters of this genus based on Meisen- heimer s original description of P. valdiviae include: a ventral (see table 1) mantle cavity that opens beneath the wingplate opposite the margin bearing the proboscis; a cymbuliid-like gelatinous wingplate with similar mus- cle pattern; a more elongated proboscis than Peraclis; sensory processes bordering the median lobe of the wing- plate; no operculum; shell unknown, but presumed to be depressed based on soft part morphology.
Procymbulia philiporum new species (figures 1-12)
Description: Coiled pseudothecosome pteropod but closely resembling Corolla Dall, 1871, in general ap- pearance. Wingplate gelatinous, oval, highly patterned with muscle, transparent at margins but becoming thick and light brown near the centerline. Calcareous shell with four whorls, thin, brown colored, sinistrally coiled. Shell depressed; spire and body whorl with prominent
growth striae parallel to aperture; aperture broad and drawn out in an elongated manner without a sharply pointed rostrum; columellar lip reduced. Shell internal within a voluminous gelatinous pseudoconch. Pseudo- conch oval, Coro//a-like in shape and consistency, length 1.5 X width, with broadly oval opening coinciding with shell aperture. Proboscis extending at 90° angle to wing- plate surface, with darkly pigmented ciliary tracks sur- rounding mouth. Two unsheathed, equal tentacles on posterior surface of proboscis. Wingplate with distinct median lobe on anterior margin; lateral sensory processes on either side of median lobe but not extending beyond wingplate margin. No operculum present.
Type locality: Approximately 3 km SW of Moore Island in the Northwest Providence Channel, Bahamas (26°14.76'N, 77°43.46'W). Depth of collection: 902 m in midwater; time: 2300 hrs; 3 Nov 1989; temperature at collection depth: 6.7 °C; surface temperature: 28.5 °C. One specimen.
Etymology: This species in named in honor of Dr. Philip Pugh, the scientific observer, and Mr. Philip Santos, the submersible pilot, who together collected the specimen.
Dimensions alive: Wingplate width: 20.2 mm; pseu- doconch length: 11.3 mm; pseudoconch maximum width: 7.3 mm; shell height: 7.5 mm, maximum shell width: 4.5 mm. Dimensions preserved: Wingplate width: 11.2 mm (highly contracted).
Remarks: Procymbulia philiporum possesses a finely sculptured, calcareous, sinistrally coiled shell (figures 1- 10). It is very fragile and of a uniform chestnut brown color (figures 1, 2), differing considerably in structure from that of P. valdiviae as described by Tesch (1948). The shell of P. philiporum is distinguished by its well- defined growth striae (figures 1-10) that lie parallel to the aperture on the spire and body whorl. The spire is depressed (figures 9, 10). There are no keels or ribs along the suture and there are no spiral ribs on the body whorl as Tesch (1948) described as the major character of the shell of P. valdiviae. The anterior margin of the aperture
Figures 1-3. Procymlmlia philiporum new species. 1. From life, posterior view turned slightly so the left side and ventral surface of the wingplate are exposed. Compare with figure 4 for labels Magnification ca. 8 x . 2. Posterior view, show ing close up of shell apex and proboscis; compare with figure 7 for labels Magnification ca. 12 x. 3. .Anterior view from the left side showing exposed pallial cavity. The gill and pallial gland are visible; compare with figures 8 and 11 for labels. Magnification ca. 10 x.
R. W. Gilmer, 1990
Page 113
Page 114
THE NAUTILUS, Vol. 104, No, 4
Figures 4-8. Procymlmlia philiporum new species. 4. Posterior view showing the left and ventral surfaces, same as figure 1. Scale = 2 mm. 5. Posterior view profile. Scale = 2 mm. 6. Dorsal view; the proboscis is visible through the transparent pseudoconch. Scale = 2 mm 7. Posterior view showing close-up of shell ape.x and proboscis. Scale = 1 mm 8. .\iiterior view from the left side
R. W. Gilmer, 1990
Page 1 15
(figure 9) is broadly expanded in an elongated manner without a sharply pointed rostrum, in contrast to the pointed rostrum of P. valdiviae {i.e., Tesch, 1948) and of ail Peraclis species. I detected no reticulation on the shell surface. The thin shell could not be removed from the animal without destruction. Consequently it dis- solved after several weeks in the preservative.
The shell is enclosed in a large gelatinous pseudoconch (figures 1-8) of the same character and proportional size as those of cymbuliids. The pseudoconch is enclosed within a delicate layer of epithelium that does not appear to bear pigment or chromatophores as is common in the cymbuliids (Lalli and Gilmer, 1989). The pseudoconch appers to be connected to the shell surface by a series of fine threads (figure 7, FT). On the anterior end, there is a pronounced cavity between the shell and pseudoconch (figures 3, 8) that is lined with a dark brown layer of tissue. The pseudoconch also dissolved in the preservative although the epithelial layer that enclosed it remained as a membrane around the visceral nucleus.
The midline of the wingplate is situated directly over the posterior-anterior axis of the shell and pseudoconch (figures 1-7). The proboscis bearing the mouth (figures 4, 5, P) projects ventral-most at 90° from the posterior \\ ingplate margin, directly over the apex of the shell and the blunt, posterior end of the pseudoconch. The expan- sive wingplate extends laterally and anteriorly, with a large median lobe (figures 4, 7, 8, ML) extending ante- rior-most, beyond the apertures of both the shell and pseudoconch. On either side of the median lobe, small dense patches occur near the wing border (figures 4, 11, SP) uiat appear to be concentrations of nerve fibrils and canals that converge from within the wingplate. They are not large, distinct processes as described in P. val- c'iviae {cf. Meisenheimer, 1905; Massy, 1932).
The wingplate is thick and heavily cross-patterned with muscle fibers (figures 1-8) which resemble the pat- tern seen in Corolla species (personal observation). The wingplate varies from almost transparent at the margins to light brow n near the center line and around the base of the proboscis (figures 2, 7). The ciliated grooves of the lateral foot lobes nearest the mouth are nearly black in color (figures 2, 7), but become almost transparent at their distal margins (figure 1). The unpaired median foot lobe (figure 11, MFL) forms a low border anterior to the mouth and appears as a light brown extension off the wingplate. The paired tentacles (figure 5, T) resemble those of P. valdiviae (cf. Meisenheimer, 1905). They are of equal size, unsheathed, and lie on the posterior surface of the proboscis. The base of each tentacle is darkly pigmented but each terminates in a round, light-colored patch on the tip (figures 2, 7). The penis extends from
10
Figures 9-10. Procijmlmlia philiporurn new species. 9. Shell, ventral view showing aperture 10. Shell, dor.sal view.
an opening near the base of the proboscis, below (dorsal to) the left tentacle (figure 7, PN).
The pallial cavity opens broadly across the anterior portion of the shell aperture (figures .3, 8, 11). The an- terior end of the pseudoconch is supported by a thick integument (figures 6, 11, IN) that extends from the pallial cavity. This integument appears to be the base of the epithelium that encloses the pseudoconch. Above (ventral to) this integument, a thick layer of the mantle (figures 6, 8, 11, MT) protrudes anteriorly beyond the aperture. The oval-shaped pallial gland is located on the ventral surface of this mantle layer. No "balancer" struc- ture {cf. Meisenheimer, 1905) occurs on the mantle bor- der of P. philiporum. Ventral to the pallial gland, a large plicate gill (figures 3, 8, 11, 12, G) originates from the right side of the visceral mass and extends anteriorly. When fully expanded in life, the gill protrudes slightly beyond the shell and lies along the midline of the pallial cavity, obscuring the pallial gland. The gill presents a large smooth surface with no deep furrows.
The intestine originates posteriorly, near the gonad (figure 12) and ends anteriorly on the right side of the pallial cavity near the gill. In its course (figure 12), it first encircles the viscera between the gonad and the digestive gland; it next extends anteriorly along the right side of the mantle cavity; it again encircles the anterior portion of the viscera before extending into the pallial cavity. The anus opens to the right of the gill at the end of a long and seemingly unsupported extension of the intestine (figures 11, 12, A), Because the anus and lower
showing exposed pallial cavity with gill and pallial gland. Scale = 1 mm. Abbreviations: CG, central ganglion; FT, fine threads connecting shell and pseudoconch; G, gill; GN, gonad; IN, integument supporting anterior end of p.seudoconch; IT, intestine; M, mouth; ML, median lobe of wingplate; MT, mantle tissue; P, proboscis; PC, pseudoconch; PG, pallial gland; PN, penis; S, shell; SP, sensory processes; T, tentacle; WP, wingplate.
Page 1 16
THE NAUTILUS, Vol. 104, No. 4
dorsal
2 mm
Figure 11. Procymbulia philiporum new species. Anterior view from the left side showing paHial cavity. Compare with figures 3 and 8 The posterior-anterior and dorsal-ventral axes of the shell are shown The gill is retracted, but can extend beyond the anterior shell border. A, anus; DG, digestive gland; G, gill; IN, integument supporting pseudoconch; IT, intestine; LFL, lateral foot lobes (paired); MFL, median foot lobe (unpaired); ML, median lobe of wingplate; MT, mantle tissue; PC, pseudoconch; PG, pallial gland; S, shell; SP, sensory processes; WP, wingplate.
intestine have twisted back in a loop to the left side of the mantle cavity in the preserved specimen, the intes- tinal path of P. philiporum resembles the "Type A" diagram of Tesch (1948: figure 34E).
Live observations: The animal was neutrally buoyant in the center of the sampler on return to the surface and slowly swam about the container when disturbed. It swam by undulations of the wingplate in the manner of the cymbuliids (Morton, 1964; Lalli and Gilmer, 1989) and appeared to be healthy with no apparent signs of damage. The animal never attempted to retract into the shell even after severe prodding and indeed this would not appear possible given the size of the wingplate.
The intestine appeared to be full throughout its length, and several fecal pellets were produced during obser- vation. The pellets were released into the pallial cavity and discarded off the anterior surface of the body by ciliary currents on the mantle. They were roughly 3 to 4 mm long and 0.5 mm in width. Recognizable contents included broken foraminifera tests, crustacean exoskel- eton fragments, and coccolithophores. No particles in the fecal contents were larger than 40 ^m.
DISCUSSION
Procymbulia philiporum clearly displays characters of both the Peraclididae and the Cymbuliidae (Table 2),
and points to the close affinity between these families. It therefore seems reasonable to reinstate the genus Pro- cymbulia Meisenheimer, 1905, to emphasize its transi- tional nature. Procymbulia philiporum clearK' shows close affinity to the family Peraclididae with respect to the coiled shell and the orientation of its internal organs. However, several new traits of the Peraclididae are now- apparent based on this description: First, the shell can be totally enclosed in a gelatinous pseudoconch, similar to those characteristic of the Cymbuliidae. Secondly, the wingplate can have a broad highly gelatinous nature also similar to the Cymbuliidae. Thirdly, an operculum can be absent and the shell can lack suture ornamentation and a pointed rostrum. Lastly, the animal may not be capable of retraction into the shell.
Meisenheimer (1905) established Procymbulia as a transition genus mostly because the pallial cavity of his specimen was comparable in position to that of the cym- buliids and opposed by 180° in comparison to those of either Peraclis or Limacina. In fact, the pallial cavity and wingplate of living specimens of Peraclis species and P. philiporum have a similar orientation with respect to their shells and neither resembles the orientation of Lim- acina. More accurate characters on which to distinguish Procymlnilia are the combined presence of the shell and pseudoconch, and the gelatinous Coro//a-Iike wingplate.
Although Peraclis and Procymbulia have coiled shells, both display an important pseudothecosome trait by
R. W. Gilmer, 1990
Page 117
posterior
anterior
Figure 12. Procymbiilia philipurum new species. Course of intestine (IT), mantle removed. A, anus; DG, digestive gland; ES, esophagus; G, gill; GN, gonad; PG, pallial gland; ST, stom- ach.
Figure 13. Peraclis bispinosa from life, posteroventral view, wingplate(WP) fully expanded; mantle covering the shell (MT) is retracted so that the ape.\ is visible. Scale = 2 mm. ML, median lobe of wingplate; P, proboscis; S, shell
encloses the shell in life (personal observation). Procym- biilia philiporum, however, more closely resembles the cymbuliids by encasing its shell in a pseudoconch, and by its apparent inability to retract into its shell possibly explaining the loss of the operculum. The wingplate of P. philiporum is also much more cymbuliid-like in thick- ness, muscle pattern, and general shape than I have seen in Peraclis.
Since Tesch (1948) closely linked Procymbulia val- diviae to Peraclis bispinosa, I have shown a partially expanded, living specimen of the latter species (figure 13) for comparison with P. philiporum. Procymbulia bispinosa has a more heavily pigmented wingplate and proboscis than P. philiporum, but the wingplate is re- duced in thickness, in extent of muscle bands, and in size relative to the shell. The proboscis and gill' of P. bispi-
making them functionally internal structures (Gilmer and Harbison, 1986; personal observation). At least three species of Peraclis [P. reticulata (D'Orbignv, 1836), P. bispinosa Pelseneer, 1888 (figure 13), and P. apicifulva Meisenheimer, 1906] have mantle tissue that completely
' Note; In a previous description of Peraclis (Lalli and (Kil- mer, 1989), we erred in stating that the gill was only retracted mantle tissue. I have now examined the gill in P. reticulata, P. bispinosa, and P. apicifulva.
Table 2. Comparison of major traits of the Peraclididae and C\ mbuliidae prior to this description of Procymlnilia.
Peraclididae
Cvmbuliidae
Coiled shell present with prolongation of columella
Shell axis oriented along posterior-anterior body axis
Shell often enclosed by voluminous mantle tissue
Operculum circular, glassy, left handed
Proboscis comprised of three footlobes fused to wingplate
Anus opens to the right inside pallial cavity
Uniform pallial gland, without transparent bands
Plicate ctenidium present in pallial cavity
Well developed buccal mass present
Retracts completely into shell
Calcareous shell in larval stage onK
Body highly gelatinous, wingplate up to 2 x bod\ length
Shell replaced in adults b\ gelatinous pseudoconch
Operculum left handed in larval forms
Proboscis similar, capable of great expansion in some genera
Anus opens to left side of pallial cavity
Pallial gland usually divided by transparent bands
No true ctenidium present
Buccal mass reduced or absent in most species
No retraction mechanism after larval stage
Page 118
THE NAUTILUS, Vol. 104, No. 4
nosa are remarkably similar in structure to those of P. philiporum. Althouj^h P. bispitwsa has extensive mantle that normally surrounds the shell, the live specimen in figure 13 w as also carefully collected with the JOHNSON SEA-LINK and shows no evidence of a pseudoconch. In addition, P. bispinosa is capable of complete retraction into its shell.
Most descriptions of pseudothecosomes are greatly hampered by the condition of the material. Much of the described variation in Peraclis species is due to twisting of the pallial cavity or wingplate (e.g., Tesch, 1948: figure 34a, b), during retraction. The mantle is much more ex- tensive in living specimens than in preserved material which always shows tremendous variation. In addition, the same confusion in Peraclis regarding terms used to describe the orientation of the soft parts with the shell (Gilmer and Harbison, 1986; Lalli and Gilmer, 1989) also exists for Procymbulia (table 1).
Descriptions of Procymhnilia valdiviae (Meisenheimer, 1905; Hubendick, 1951) suggest that the body and shell have an orientation similar to those of P. philiporum. Whether a pseudoconch is present remains unknown, although Massy (1932) described a firm membrane sur- rounding the viscera in her specimens. This tissue could be the epithelium that encloses the pseudoconch. It seems doubtful that the shell or pseudoconch of P. philiporum would ever survive the rigors of net collection or routine fixation. Both structures on my specimen dissolved within two weeks of preservation. A similar condition could be expected for P. valdiviae.
Tesch (1948) provided the most complete description of what he considered to be Procymbulia valdiviae. He found it so similar to Peraclis bispinosa that he removed its standing as a genus and discounted any transitional status it displayed between the Peraclididae and the Cymbuliidae. However, five facts suggest that the spec- imens Tesch used to make his determination are probably a new species of Peraclis rather than specimens of P. valdiviae: 1) the shells bear distinct PeraclisAiVe rostra and suture ornamentation; 2) the shells survived net col- lection and years of preservation; 3) only his specimens bear an operculum; 4) Tesch s figures show a Peraclis- like 90° twisting of the wingplate, indicating partial re- traction into the shell. Figures of P. valdiviae from Mei- senheimer (1905), Bonnevie (1913), Hubendick (1951), and my preserved specimen of P. philiporum all have the wingplate situated in its unretracted position (the proboscis over the gonadal whorl) suggesting Procym- bulia does not display this type of retraction. And finally, 5) Tesch found no lateral processes bordering the median lobe of the wingplate.
Procymbulia appears to be cosmopolitan in its distri- bution and represented by at least two species. Based on the collections of Meisenheimer (1905) and Massy (1932), it would appear that P. valdiviae probably occurs in the circumgiobal .southern oceans, primarily in deep water. As stated above, Tesch "s (1948) Indo-Pacific specimens most likely belong to a new species of Peraclis. Bonnevies (1913) description of P. michaelsarsi from a single spec-
imen collected in the N.E. Atlantic may be very similar to P. philiporum. Based on her brief description, the shape of the gonadal whorl and the orientation and pig- mentation pattern of the proboscis resemble P. philipo- rum. Hubendick (1951) and Tesch (1946) may also have collected P. philiporum, since all of these Atlantic spec- imens assigned to P. valdiviae lack the large sensory processes on the anterior wingplate margin characteristic of this latter species. Hubendick s figures closely resemble my preserved specimen, and Tesch (1946) described a similar pigment pattern to that of P. philiporum but indicated that an operculum was attached to the wing- plate of his specimens. My animal shows no scar or other indication of ever having had an operculum. Tesch's specimens were considerably smaller than mine, how- ever, and the operculum may be lost at an earh- age.
ACKNOWLEDGEMENTS
I gratefully thank Dr. G. R. Harbison for providing sub- mersible time and support. Dr. Carol M. Lalli and two reviewers for comments on the manuscript, Paula Mik- kelsen and Amelie Sheltema for comments on the ori- entation of gastropods, and R. Presley for help in manu- script preparation. Research supported by N.S.F. grants OCE 85-16083, OCE 87-46136, OCE 87-01388 and an in-house grant from Harbor Branch Oceanographic In- stitution, all to G. R. Harbison. Support for the color plates was provided by a grant from Conchologists of America and by THE NAUTILUS. This is Harbor Branch Oceanographic Institution Contribution No. 793 and Direct Studies of Mesopelagic Communities Contribu- tion No. 22.
LITERATURE CITED
Bonnevie, K. 1913. Pteropoda Report of the "Michael Sars"
North .'\tlantic Deep Sea Expedition 3: 1-85. Gilmer, R W. and G R. Harbison. 1986 Morphology and
field behavior of pteropod molluscs: feeding methods in
the families Cavoliniidae, Limacinidae and Peraclididae
(Gastropoda: Thecosomata). Marine Biology 91:47-57. Hubendick, B. 1951. Pteropoda, witli a new genus Further
Zoological Results of the Swedish .Antarctic Expetlition
1901-1903 4(6):1-10. Lalli, C M and R. W. Gilmer. 1989. Pelagic snails The
biology of holoplanktonic gastropod mollusks. Stanford
University Press, 259 p. Massy, A. L. 1932. Mollusca: Gastropoda Thecosomata and
Gymnosomata. Discovery Reports 3:267-296. Meisenheimer, J 1905. Pteropoda. Wissenschaftliche ergeb-
nisse der Deutschen Tiefsee Expedition auf dem Dampfer
••\aldivia" 1898-1899 9(1):1-314. Meisenheimer, J 1906 Die Ptero[)oden der deutschen Siid-
polar-Expedition 1901-1903. Deutsche Siidpolar-Expedi-
tion IX. Zoologie 1:94-153 Morton, J. E. 1964. Locomotion In. \\ ilbui, K and C. M.
^'onge (eds). Physiology of the Mollusca. Academic Press,
1 :383-423. Spoel, S. van der. 1976. Pseudothecosoinata, Gv nino,soinata
R. W. Gilmer, 1990
Page 119
and Heteropoda (Gastropoda). Bohn, Scheltema, and Hol- kema, Utrecht, 484 p
Tesch, J. J. 1913. Pteropoda. In: F. E. Scliulze (ed.). Das Tierreich. R. Friedlander & Sohn, Berlin, 36; 1-154
Tesch, J. J. 1946. The thecosomatous pteropods. I. The At- lantic. Dana Reports 28:1-82.
Tesch, J J 1948. The thecosomatous pteropods. 11 The Indo- Pacific. Dana Reports 30:1-45.
Tietze, R C. and A. M, Clark. 1986. Remotely operated tools for undersea vehicles. In: T. McGuiness (ed.). Current practices and new technology in ocean engineering. Amer- ican Society of Mechanical Engineers 11:219-223.
THE NAUTILUS 104(4):120-129, 1990
Page 120
Studies on Bathyal and Abyssal Buccinidae
(Gastropoda: Neogastropoda):
1. Metula fiisiformis Clench and Aguayo, 1941
M. G. Haraspwyrh
Dt'parliiu'iil ol lii\frtcl)r;i(f Zoology National Museum ol X.ilural History Smithsonian Institution Washington. IX: 20560, VS.\
ABSTRACT
Based on the morphology of the radula and shell, Metula fii- sijorntis Clench & .-Xguayo, 1941 is transferred to the pretlom- inantU Inilo-western Pacihc genus Wanario. This species occurs in upper t-ontinental slope communities (liS3-578 m) of the (.'arihhean Sea and the northern coast of South America. The holotype was collected dead in 2,633 m, well below the depth inhabited by this species. The large well-developed gland of Leiblein, a separate sperm ingesting gland between the capsule gland ami albumin gland, and three-cusped rachidian teeth are features that Manaria shares with other fusiform buccinids (e.fi,.. Penion. Scrratifusti.s) as well as with primitive members of other families within Muricacea These features are inter- preted as being symplesiomorphic, and suggest that the fusi- form buccinids are among the more primitive members of the Buccinidae.
Key Kurds: Buccinidae; Caribfiean; bath\al; Manaria: Me- tula.
INTRODUCTION
The family BiKciiiidao comprises one of the most diverse arui dominant groups of predatory prosobranch gastro- pods at high latitudes and at bathyal, abyssal and hadal depths. It is repre.sented in the fossil record of the Lower Cretaceous (Albiari), and ranks among the oldest of the neogastropod families (Taylor et (il., 1980), Like most predatory prosobranch families, it is believed to have evolved in temperate climatic zones at higher latitudes (Sohl, 1987). .Although the majority of these families be- came predominantly tropical during the Onozoic, most Buccinitlac remained in temperate and polar regions, were the family diversified since the late Miocene (Taylor et al., 1980). The success of Buccinidae at high latitudes and in the deep .sea has been attributed to their broaii habitats and diets, which are considered to be adaptations to unpredictable resources (Taylor, 1978).
Despite the high diversity and abundance of Buccin- idae, the systematics of this group is [loorly imdcrstood at all laxonomic levels. This is due, in large part, to the
fact that the vast majority of taxa are based exclusively on features of the shell and operculum, supplemented occasionally by observations on radular morphology. Shells of Buccinidae tend to be simple, and offer few readily discernible morphological characters. These are subject to convergence, especially in polar regions and the deep sea, where effects of habitat on shell form are most pronounced (Graus, 1974).
Detailed anatomical data are available for compara- tively few, mainK shallow-water taxa (e.g.. Dakin, 1912; Golikov. 1963, 1980; Kosuge, 1967; Ponder, 1973; Lus, 1981; Kantor, 1990). The lack of well-defined, synapo- morphic anatomical features (other than radular mor- phology), even between the families Buccinidae. Nas- sariidae, Fasciolariidae, and Melongenidae have led Ponder (1973a) to suggest these groups might all be con- sidered subfamilies of Buccinidae. This arrangement was subsequently adopted b\ Ponder and W'aren (1988).
Bouchet and Waren (1985) revised the deep-water Buccinidae {sensu Wenz, 1943) of the northeastern .At- lantic Ocean, and later (Bouchet & Waren, 1986) re- viewed many of the tropical deep-w ater si)ecies. Despite the.se significant contributions, most of the nearly 200 supraspecific taxa v\ ithin Buccinidae (sensu Wenz, 1943) are poorly defined, and the assignment of many species to genera remain tentative.
■Among the taxa listetl In Bouchet and Waren (1986) as ■insufficientb known is Metula Jusiformis Clench and .Aguayo, 1941. The placement of this species in Met- ula was disputed by Olsson and Ba\er (1972) who sug- gested that it had affinities with Fusinus or a fusiform bui'ciiiid .\l)bott (1974) referred this species to the genus Bartschia. Bouchet and Waren (1986) considered it to be a buccinid, and commented on its conchological re- semblance to Euthriostoina.
During a recent dive aboard the research submersible Johnson-Sea-Link I off Nava.ssa Island, situated off the southwestern peninsula of Haiti, the author had the op- portunity to observe and collect several living specimens of "Mctnia" fusifonnis. These observations, together with data irom ailditional material discovered in the L'SNM
M. G. Harasewvch, 1990
Page 121
collections, form the basis of this report, the first in a series on enigmatic deep-water buccinid ta.xa.
MATERI.ALS AND METHODS
Five specimens of "Metida fiisiformis Clench anil Aguayo, 1941 were observed, recorded on videotape and collected either in (1 specimen) or within 2 meters (4 specimens) of a bucket baited with decomposing octopus and set on an ooze-covered area (slope about 20°) off the west coast of Navassa Island (18°24'42"N, 75°03'00"W) at a depth of 578 m for 50 hours. The specimens, which were moribund upon reaching the surface, were fixed in 10% neutral buffered formalin and stored in 70% ethanol until dissection.
Phenetic analyses were used to assess the relationships of three conchologicaiiy similar taxa, each proposed on the basis of a single specimen. All specimens listed in the "material examined" section, as well as the holot\ pe of Biiccinoftisus suhnamensis Okutani, 1982 and two spec- imens of a southern variant of Biiccinutu canetac Clench and Aguayo, 1944, described as Plicifusus jamarci Oku- tani. 1982, were scored for the 11 shell characters listed in table 1. These data were standardized (mean = 0, standard deviation = 1), a Euclidean distance matrix calculated, and a phenogram based on the UPGMA clus- tering algorithm was produced using SYSTAT version 4.0 (Wilkinson, 1988). A Principle Component Analysis using the same data matrix (25 specimens x 11 char- acters) was performed, also using SYSTAT, and the in- dividuals plotted using the first two principal components as axes.
Repositories of examined specimens are indicated by the following abbreviations:
MCZ — Museum of Comparative Zoolog\ , Harvard L ni-
versity NSMT — National Science Museum, Tokyo USNM — National Museum of Natural Histor\, Smith- sonian Institution
SYSTEMATICS
Family Buccinidae Rafinesque, 1815 Genus Manaria E. A. Smith, 1906
Manaria fiisiformis (Clench & Aguayo, 1941) (figures 1-5, 7-17)
Metula fiisiformis Clench & .\gua\o, 1941:179, pi. 1-4, fig. 1;
Bouchet & Waren, 1986:485, fig. 116. "Metula" fiisiformis Clench & .\gua\o. — Olsson & Ra\or, 1972:
925. Bartschia fiisiformis (C^lench & .\gua\o). — .-VIjIjoU, 1974:217. Mohniu kaichcrae Petuch. 1987:103, pi. 21, figs. 8, 9.
Shell morphology: Shell (figures 1, 3, 4, 5) to 69 mm, thick, biconical, fusiform, Protoconch badl\ eroded or missing on all adult specimens examined. Protoconch of juvenile specimen (figures 7, 8) just over one smooth whorl, with a diameter of 0.75 mm. Transition to teleo-
I'alilc I. Shell iharacter.s ii.scd for plii'iictic analv.sLs Cliar- .iclcrs I through 8 descrihe the gfoniclr\ ol llu- gfiicralized s\w\\ form (Harasewvch. 1982).
4
5, 6.
I .
8.
9.
10,
Shape <il the generating tiir\e of the liod\ ea\it\ (She).
Shape ol the generating curve of the siphonal canal (Ssc).
Helati\e siplional length (Ksl),
Siphonal angle (0),
.\ngle of the generating curve (6).
Rate of « horl expansion (W).
Position of the generating cur\e relati\e to the axis (D),
Rate of whorl translation (T),
Spire angle {a)
.Nimiber oi axial ribs on lourlh leleoeimch u horl (no rib).
Number ol spiral eord.s on lourlh teleoeoniii whorl mo,
cord).
conch gradual, marked by formation of axial ribs, fol- lowed within V: whorl b\' the formation of six fine spiral cords. Teleoconch of up to 8% convex whorls, rounded at first, becoming sharply shouldered by the fifth post- nuclear whorl. Suture broadh adpressed. Axial sculpture of broad, rounded, regularh -spaced, axial to slightK pro- socline ribs that do not extend onto the anteriormost portions of the body whorl or the siphonal canal. Axial ribs number 11-12 on the first and 11-16 on the penul- timate whorl. Spiral sculpture of strong cords, as broad or broader than intervening spaces, that overlay axial ribs. Cords number 12-13 between suture and shoulder, 19-21 between shoulder and siphonal canal, 16-18 on siphonal canal. Sixteen to 21 cords remain exposed on penultimate whorl. .Aperture elliptical, tapering poste- riorly beneath suture to form anal sulcus. Outer lip with 18-23 thin spiral lirae pronounced beneath axial ribs and weak or absent between. Inner lip smooth, with thin, porcellaneous inductura. Columella solid, sinuate, lack- ing folds. Siphonal canal broad, slightK shorter than ap- erture, crossing coiling axis. Siphonal fascicle weak, ad- jacent to columellar edge of siphon. Exterior surface of shell dull ivory to light amber, aperture and columella white. Periostracum (figure 9) thick, straw-colored to brown, consisting of thin, axial blades that are broadest between spiral cords and abraded along their surfaces. Operculum (figures 2, 13, op) thick, elongate, with ter- minal nucleus (usually abraded), attached along slightly less that V2 of its inner surface, glazed along posterior and left inner margins, fills aperture '4 w horl from outer lip.
Shell ultraslructure: (figure 10) Shell composed of three layers of crossed-lamellar crystals and an outermost pris- matic layer. Innermost layer (—200 nm) with crxstal faces oriented at approximately a 35° angle to growing edge of the shell; crystal faces of next layer ( — 250 ^m) perpendicular to growing edge; outermost crossed-la- mellar layer (—625 ^m) parallel to growing edge. Pris- matic layer of varying thickness (50-200 fim) outermost, comprising the spiral cords and contains all of the shell color. Inner three lasers white.
Page 122
THE NAUTILUS, Vol. 104, No. 4
/\
*»
^ V
\
^.
M. G. Harasewvch, 1990
Page 123
External anatomy: (figure 13) Soft tissues comprise 3'/2- 4 wliorls, mantle cavit)' spans % whorl, kidney '/4 whorl, digestive gland 2'/:-3 whorls. Columellar muscle long, narrow, attaching to shell I'/s whorl behind mantle edge. Foot small, rectangular (L/W = 1.4) with thin, deep propodial groove along leading edge of sole, .\nimal uni- form khaki to tan in color. Head small, with pair of thin, tapering cephalic tentacles with round black eyes at their bases. Siphon (figure 13, s) short, muscular.
Mantle cavity: Arrangement of mantle cavity organs similar to that of Bucciniiiii iindatum Linne, 1758 (Fret- ter & Graham, 1962: fig. 180B). Mantle with thick, mus- cular band (figure 13, mb) along edge, thin, transparent posteriorly. Osphradium bipectinate, large, dark brown, with 70-80 filaments above ganglion and 62-68 below, Ctenidium, twice as long and slightly narrower than osphradium, sharply tapered along anterior edge. Hy- pobranchial gland (figure 13, hg) broad, thick, viscous and clear in water, solid and opaque in alcohol.
Alimentary system: Proboscis (figure 14, pb) long (1.5 X shell aperture length), narrow (1.2 mm), pleurombolic, retracts to rear of cephalic hemocoel, overlying salivary glands anteriorly and gland of Leiblein posteriorly. Buc- cal mass, as long as introverted proboscis, with radular sac extending slightly from its posterior margin. Radula (figure 12) short (6.0-7.9 mm, n = 3), composed of 102- 108 rows of teeth. Rachidian tooth with three cusps of equal length located on central portion of broad, basal plate. Lateral teeth with two cusps, outer cusp 1.5 times as long and broad at its base as inner cusp. Salivary glands (figure 14, sg) large, irregular, with ducts becoming em- bedded in wall of esophagus (within dorsal folds) anterior to valve of Leiblein (figure 14, vl). Gland of Leiblein (figure 14, gl) long, convoluted, posteriorly tapering, fill- ing posterior % of cephalic hemocoel, emptying via a thin duct into the posterior region of the mid-esophagus. Stomach (figures 13, 14, sto) simple, U-shaped, with two widely separated ducts to digestive glands. Intestine thin, tubular, with longitudinal folds, rectum (figure 14, r) little expanded, simple. Anal gland absent.
Female reproductive system: A narrow oviduct leads from the large yellow-orange ovary to the albumen gland, which lies along the anterior right wall of the kidney. The pallial portion of the female gonoduct (figure 15) consists of a large sperm ingesting gland (figure 15, ig), long, narrow capsule gland (figure 15, eg) and a muscular bursa copulatrix (figure 15, be) with the female opening (figure 15, fo) situated ventral to the anus (figure 15, a).
Male reproductive system: Testis (figures 13, 16, te) orange tan, along right side of digestive gland. Testicular
duct (figure 16, td) tubular, about 0.3 mm in diameter, becomes convoluted along adaxial wall of kidnev to form seminal vesicle (figure 16, sv). Duct straightens before passing along wall of pericardium and entering rear of mantle cavit> (figure 16, rmc). The prostate gland (figure 16, pr) is narrow, and runs along the right wall of the mantle cavity, ventral to the rectum. The tubular vas deferens (figure 16, vd) runs from the prostate gland anteriorly along the floor of the mantle cavity to the base of the penis (figure 16, pen), which is approximately Vt the length of the mantle cavitv, dorsoventrally com- pressed, truncated, and with a terminal papilla (figure 16, pap) emanating from a depression along its distal lateral wall.
Material examined: Holotype, MCZ 135290, Atlantis sta. 3344, trawled off Cienfuegos, Cuba (2]°38'N, 80°12'W), in 1,440 fms (2,633 m); Holotype of Molmia haicherae Petuch, 1987, L'SNM 859855, off Los Monges Islands, off mouth of Gulf of Venezuela, Venezuela, in 200 m; USNM 875112, Johnson-Sea-Link I sta. 2321, off west coast of Navassa Island (18°24'42"N, 75°03'00"W), in or near carrion-baited bucket left in 570 m for 50 hours [5 specimens]; USNM 854016, Johnson-Sea-Link I sta. 2320, off Lulu Bay, Navassa Island (18°22'42"N, 75°02'44"W), on small tree branch in 530 m [2 juvenile specimens]; USNM 832953, off Long Point, south shore of St. Croix, US Virgin Islands, in 160 fms (293 m) [10 specimens]; USNM 832954, off Salt River Canyon, north shore St. Croix, US Virgin Islands, in 230 fms (420 m) [2 specimens]; USNM 811332, R/V Oregon sta. 4225, 150 miles north of Sao Luis, Maranhao, Brazil (00°18'N, 44°23"W), in 100 fms (183 m) [1 empt> shell].
Ecology: Like many buccinids, this species is attracted to carrion, and is at least a facultative scavenger. The five specimens of Manaria fusiformis were the only gas- tropods collected in or near the baited trap. Also present in the trap were several dozen isopods (Booralana tri- carinata Camp & Heard, 1988). The two juvenile spec- imens were collected from a single fragment of sunken wood that was also inhabited by three chitons, about 20 skeneiform trochids, and that contained teredinids and burrowing sipunculans. Water temperatures at the two Johnson-Sea-Link stations at w hich this species was col- lected were 9.7° C (JSL-I-2320) and 9.9° C (JSL-I-2321). Gut contents of three adult specimens were examined, but did not reveal identifiable remains. The bathymetric range of all live-collected specimens was 293-578 m.
Geographic range: (figure 17) This species is presently known only from the northern and eastern Caribbean Sea, and from along the northern coast of South America.
Figures 1-5. Manaria fuxiformis (Clench k Aguayo, 1941), I. I'SNM 87,51 12, j.Sl,-l sta. 2321, off west coast of Navassa lslaii(f 15 X. 2. Operculum of specimen in figure 1. 3 0 x, 3. Holotype of Mctnia fusiformis (,'leiicli & .Aguayo, MCZ 135290, Atlantis sta. 3344, off Cienfuegos, C;uba in 2,633 m. 1.5 x. 4. USNM 811332. 150 miles north of Sao Luis, Maranhao, Brazil in 183 m. 1.5 X. 5. Holotype of Muhnia kaichcrae Petuch. 1987, USNM 8.59855. off Los Monges Islands, off mouth of Gulf of N'enezuela, Venezuela, 200 m. 1.5 x Figure 6. Buccinofussus surinamensis Okutani, 1982. Holotype NSMT Mo 60028, off Surinam. 1.0 x.
Page 124
THE NAUTILUS, Vol. 104, No. 4
Figures 7-12. Metttla fusiformis Clench & Aguayo. 7. A.xial view of protocomli of juvenile specimen (USNM 85-1016). Scale bar = 200 ^in. 8. Lateral view of same protoconch. Scale bar = 200 ^m. 9. Periostracum Scale bar = 500 fim. 10. Shell iiltrastnicture, fracture surface parallel to growing edge, Vz whorl beliiiui lip Scale bar = 250 ^m 1 L Radular ribbon of juvenile specimen (USNM 85-1016), lateral teeth removed from right side. Scale bar = 5 ^m '2. Hadular riblxm of adult specimen (specimen in figure 1). Scale bar = 100 ^m.
M. G. Harasewych, 1990
Page 125
Figures 13-16. Anatomical features of Manaria fusiformis (C;lencli and Aguayo), I.'J. Male speeimen, lateral view. IJ-. Alimentary system. 15. Female reproductive system. 16. Male reproductive system, a, anus; aa, anterior aorta; be, bursa copulatrix; eg, capsule gland; cm, columellar muscle; dg, digestive gland; fo, female opening; gl, gland of Leiblein; hg. liypobranchial gland; ig, ingesting gland; k, kidney; nib, muscular band of mantle; ng, nephridial gland; nr, nerve ring; op, operculum; pap, papilla; pb. proboscis; pc, pericardium; pen, penis; pro, prostate gland; r, rectum; s, sipfion; sg, salivary gland; sto, stomach; sv, seminal vesicle; td, testicular duct; te, testes; vd, vas deferens; vl, valve of Leiblein.
Page 126
THE NAUTILUS. Vol. 104, No. 4
Figure 1 7. Geographic distribution of Metula fusijvrmis. Sol- id star denotes type locality Open star denotes type locality of Mohnia kaicherae.
DISCUSSION
.\lthmigh originally described in the genus Metula, the generic placement of M. fusiformis Clench and Aguayo, 1941 has undergone considerable, if speculative, pere- grination during the intervening decades. The radula of this species, with three-cusped rachidian teeth and two- cusped lateral teeth (figures 11, 12), differs from that of Metula H. and A. Adams, 1853 (Bouchet, 1988: fig. 1), and precludes the suggested affinities with Fusinus or any fasciolariid (Olsson & Bayer, 1972:925), or with Eu- thriostoma (Bouchet & Waren, 1986:485). This radula most closely resembles those of species in the genera Eosipho Thiele, 1929 and Manaria Smith, 1906 (Bouchet & Waren, 1986: figs. 13-17, 19-24). Ontogenetic changes in the morphology of the rachidian tooth of M. fusifor- mis include the broadening and lateral expansion of the basal plate, as well as the thickening and redirection of the cusps to a parallel orientation (figures 11, 12). Similar ontogenetic changes in Manaria lirala Kuroda and Habe, 1961 have been illustrated (Bouchet & Waren, 1985: figs. 20, 23). The presence of pronounced axial ribs overlaid by thick spiral cords, a spire that is more than half the shell length, and a well differentiated siphonal canal in M. fusiformis, in Manaria thurstoni Smith, 1906 (the type species of Manaria), and in several Japanese species of Manaria, as well as the lack of these features in Eosi- pho smithi (the type species of Eosipho) support the transfer of Metula fusiformis to the genus Manaria.
A UPGVIA phenogram (figure 18) of the 21 available specimens (including the holotype) of Manaria fusifor- mis, the holotypes of Burcinofusus surinamensis Oku- tani, 1982 and Mohnia kaicherae Peluch, 1987, as well as two specimens of Buccinuni canetae (jamarci form), together with a plot of scores of the first two principal components for these specimens (figure 19) indicate that the holotype of Mohnia kaicherae falls within the range of variation of Manaria fusiformis. This holotspe (figure 5, 18K, 19K), which has six teleoconch whorls, is inter- mediate in morphology between the two juvenile spec- imens of Manaria fusiformis (figures 18e, 19e), which
J J
s
a c a c d a b F b b a a a a b a a a b K e e
3 2 10
Figure 18. Phenogram of UPGMA clustering of Euclidean distances using standardized data. a-e. Manaria fusiformis. a. I'SNM 83295.3, .St. Ooix [10 specimens], b. USNM 875112, Navassa [5 specimens], c. I'SNM 832954. St. Croix [2 speci- mens] d. USNM 811.3.32, Brazil, e. LSXM 854016, Navassa [2 jineiiile specimens). F. Holot) pe of Metula fusiformis C^lench & .\gua\o j. Soutliern variant ol Buccinnm canetae described as Plicifusus jamarci. K. Holotype of Mohnia kaicherae Pe- tnch. S. Holotype of Buccinofti.sus surinamensis Okntani.
have 3.8 and 4() teleoconch whorls, ami the remaining adult specimens (figures 18, I9a-d). \\ liich ha\(> between 8.0 and 8.75 whorls. Thus, Manaria fusiformis can be seen to undergo allometric grow th in shell and radular form.
The lu)lot\ pe of Buccinofusus surinamensis Okutani,
M. G. Harasewvch, 1990
Page 127
Table 2. Survey of the subfamilies of Buccinidae (according to Ponder & Waren, 1988) for morphologies of the glariH ot Leiblein (gLi. sperm ingesting gland (ig), and number of cusps on rachidian teeth (rach), gL: 0 = absent, 1 = reduced, flaccid; 2 = large, glandular, ig: + = present; — = alKent; '' = unknown.
Buccinidae
Manaria fiisijormis (herein)
Penion (Ponder, 1973)
Scrratijiisus (Harase«\ch, 1990)
Bucciniim uiulatum (Dakin, 1912; Fretter, 1941)
Neptunea (Golikov, 1963)
Retifttsus tenuis (Kosuge, 1967)
Tacita arnoldi (Lus, 1981)
Volutopsius (Kantor, 1990)
Thalassoplancs moerchi (Lus, 1973)
Nassariinae
Illyanassa obsolcta (Brown, 1969; Fretter, 1941)
Melongeninae
Busycon carica (Harasewvch, 1982a) Mclongcna corona (Harasewvch. 1982a)
Fasciolariinae
Leucozonia nassa (Marcus & Marcus, 1962) Microfulgur carinatits (Ponder, 1970)
+ + + +
+ ? ? ?
3
3
3 >3 2, 3, >3
3
4 1,3, >3
1
>5
4-8 3
+
1982, a species synonymized with A/, jusiformis bv Bouchet and Waren (1986:485), is more similar in shell morphology to Plicifusus jamarci Okutaiii, 19S2 than to any specimens of A/, jimjonnis. and is therefore re- moved from the s\ nonvmy of A/. Jusiformis. In addition to being separable on the basis of the continuous char- acters listed in table 1, both Buccinofusus surinamensis and P. jamarci differ from Manaria jusiformis in having a substantially larger, chalky, white shell with deeply receding spiral lirae along the outer lip of the aperture. The presence of a large, well-developed gland of Leib- lein, simple, three-cusped rachidian teeth, and a female reproducti\e svstem with a distinct sperm ingesting gland between the albumen gland and the capsule gland in Manaria (herein), Penion (Ponder, 1973), and Serrati- fusiis (Harasewych, 1990), represents a combination of
characters uncommon within Buccinidae (table 2). Each of these features occurs widely throughout the Muricoi- dea (table 3), suggesting that these are plesiomorphic characters, and that the fusiform buccinids are among the more primitive members of the family Buccinidae. Finally, it is suggested that the depth at which the holotv pe of M. fusiformis was collected (2,633 m) falls outside the batlnmetric range of the species, and rep- resents post-mortem transport of the shell into greater depths. All living specimens of Manaria fusiformis were taken between 183 m and 578 m, indicating that this species is a member of upper slope communities. Batln- metric zonation along the continental slope has been w ell documented (e.g., Okutani, 1968), and bathv metric ranges of species have been found to be narrower on the upper slope than on the middle slope (Hecker, 1990).
Table 3. Sur\ev of the tainilies of Muricoidea (according to Ponder & Waren, 1988) for morphologies of the gland of Leiblein (gL), sperm ingesting gland (ig), and number of cusps on rachidian teeth (rach), gL: 0 = absent, 1 = reduced or modihed; 2 = large, glandular, ig; -I- = present; — = absent Reported features are present in some, but not necessariK in all. members of the listed families.
kI.
Ig
Muricidae (Houston, 1976; Harasewych, 1984)
Turbinellidae (Harasewych, 1987)
Buccinidae
Columbellidae (Marcus & .Marcus, 1962a; Houston, 1976)
Volutidae (Ponder, 1970a)
Olividae (Marcus & Marcus, 1959; Ponder & Darragh, 1975)
Harpidae (Bergh, 1901)
Marginellidae (Ponder, 1970b)
Mitridae (Ponder, 1972, 197:3a)
X'olutomitridae (Ponder, 1972, 1973a)
Costellariidae (Ponder. 1972. I97.3a)
|
2 |
+ |
3 major + minor |
|
2 |
+ see table 2 |
3 |
|
1 |
- |
0 |
|
2 |
-1- |
3 |
|
2 |
-1- |
3 |
|
0 |
-1- |
3 |
|
1 |
+ |
1-20-1- |
|
0 |
+ |
3 or more |
|
1 |
+ |
1 |
|
2 |
+ |
3 or more |
Page 128
THE NAUTILUS, Vol. 104, No. 4
-r
-2-1 0 1 2
Figure 19. Plot of scores of first two principal components, .abbreviations as in figure 18.
ACKNOWLEDGEMENTS
The invaluabie assistance of the crews of the Johnson- Sea-Link 1 submersible and the R/V Edwin Link is grate- fulK acknowledged. 1 thank Kathcrine Jones for pre- paring the anatomical illustrations, and Susanne Bradon for assistance with Scanning Electron Microscopy. Drs. Philippe Bouchet, Museum national d'Histoire natu- relle, Paris, Winston F. Ponder, Australian Museum, Syd- ney, and Anders Waren. Swedish Museum of Natural History, Stockholm, provided valuable comments on the manuscript. This is contribution number 250 of the Smithsonian Marine Station at Link Port, and contri- bution number 810 of the Harbor Branch Oceanographic Institution.
LITERATURE CITED
.-Vbbott, K. T. 1974. .American seashells, 2nd ed. van Noslrand Heinhold Co., New York, 66.3 p., 24 pis.
Bergh, H 1901 Beitrag zur Kemitniss der Ciatliiiig Harpa. Zoologi.sclie Jahrbiicher 14(4):609-629, pi. 47,
Bouchet, P. 1988. Two new species of Metula (Gastropoda; Buecinidae) with a description of the radula i}| the genus Tfie .Nautilus 102(4): 149-1.5.1
Bouchet, P. and .V Waren. 198,5. Revision ot the northeast .Mlantic bathyal and abyssal Neogaslropoda excluding Turridae (Molhisca. Gastropoda), Bollettitid Malacologico. Suppleniento 1:121-296
Bouchet, P. and A. Waren. 1986. Molhisca Gastropoda: tax- onomical notes on tropical deep water Buecinidae with descriptions of new taxa. Memoires du Museum national d'Histoire natureile. Paris (A) 1334.57-499, pis. 1-18.
Brown, S. C^ 1969 The structure and function of the digestive system of the mud snail Sassariiis ohsolcttis (Sav), Malaco- logia 9(2):447-500.
Clench, W. J and C. G. Aguayo. 1941. Notes and descriptions of a new deep-water Molhisca obtained by the Harvard- Havana expedition off the coast of Cuba, 4. Memorias de
la Sociedad ile Historia Natural "Felipe Poey ' 15:177- 181,
Dakin, W, J 1912 Buccinum. (The whelk) Proceedings and Transactions of the Biological Societv, Liverpool 26:253- 367.
Fretter, V. 1941. The genital ducts ol some British stenoglo.s- san prosobranchs. Journal ot the Marine Biological \ss,o- ciation of the L'nited Kingdom 25:173-211,
Fretter, V, and A. Graham, 1962, British prosobranch mol- luscs, Ray Society, London, 7.55 p,
CJolikov, .\. N. 1963. Gastropod mollusks of the genus .Vcp- lunea Bolten. Fauna of the USSR, mollusks 5(1), .\ka- demia Nauk. Leningrad, 219 p
Golikov, A. N. 1980. Buecinidae of the World Ocean. Fauna of the USSR, mollusks 5(2). Akademia Nauk, Leningrad, 508 p.
Graus, R. R, 1974, Latitudinal trends in the shell character- istics of marine gastropods, Lethaia 7.303-314,
1 larasew\ch, M, G, 1982 Mathematical modeling of the shells of higher prosobranchs. The Bulletin of the .\merican Mal- acological L nion 1981:6-10.
Harasewych, M. G. 1982a. The evolution and zoogeograph) of the subfamily Busyconinae (Gastropoda: Melongeni- dae). Ph.D. dissertation. University of Delaware, 216 p.
Harasewych, M. G. 1984. Comparative anatomy of four prim- itive muricacean gastropods: implications for trophonine plnlogen\-. .American Malacological Bulletin 3(1): 11 -26.
Harasew) ch, M, G, 1987, A revision of the genus Benthovolu- ta with notes on the evolution of the subfamiK Pt\cha- tractinae (Prosobranchia: Turbinellidae). The Nautilus 101(4):166-181.
Harasewych, M. G. 1990. The columbariform ga.stropods of New Caledonia. Memoires du Museum national d Histoire natureile, Paris, (A). In press.
Hecker, B. 1990. N'ariation in megafaunal assemblages on the continental margin south of New England. Deep-Sea Re- search 37(l):37-57,
Houston, R, 1976, The structure and function of neogastropod reproductive systems: witli special reference to Colutn- bella fitscata Sowerby, 1832. The Veliger 19(l):27-46.
Kantor, Yu. I. 1990. Gastropods of the subfamily V'olutopsi- inae of the World Ocean. Nauka, Moscow, 180 p., 16 pis.
Kosuge. S. 1967. On the transfer of " Phtiuwrhychus?" tenuis Okutani, 1966 to the famiK Buecinidae. \'enus 25(2):59- 64, pis. 3, 4,
Lus, V. Y'a. 1973. A new fasciolariid iMollusca, Xeogastropo- da) from the lower abyssal region of the north Pacific. Transactions of the Institute of Oceanographv, Academy of Sciences, USSR 91:203-212.
Lus, \' Y'a. 1981. A new species of Tacita (Prosobranchia. Buecinidae) with wide distribution in the north-western part of the Pacific Ocean. Transactions of the Institute of Oceanolog), Academ\ of Sciences. L'SSR 115:140-154
Marcus. E, and F, Marcus, 1959, Studies on "Olividae", Bole- tim Faculdade de Filosofia, Cieneias e Letras. I'niversi- dade de Sao Paulo no, 232, Zoologia no. 22:99-188, pis. 1-11
Marcus, E and 1' Marcus 1962 On Leitcozonia nassa . Tio\e- tim Faculdade de I'ilosofia, Cieneias e Letras, Universi- dade de Sao Paulo no 261. Zoologia no. 24:ll-.39.
Marcus, F and F. Marcus, 1962a, Studies on Columbellidae Boletim Faculdade de Filosofia. Cieneias e Letras, Uni\er- sidade de Sao Paulo no. 261, Zoologia no 24:3.35-4()2
Okutani, T. 1968 S\stemalics, ecological distribution, and palaeoecological implications ol arcliibenllial and ainssal
M. G. Harasewvch, 1990
Page 129
inollusca from Sagaini Ba\ and adjacent areas. Jonrnal ol the P'acultv of Science, Tok\o University (section 2, Ge- ology) 17:1-98.
Okutani, T. 1982. A new genus and five new species of gas- tropods trawled off Surinam. \'enus 41(2):109-120.
Olsson, A. .\. and F. M Bayer. 1972. American metulas (Gas- tropoda: Buccinidae). Bulletin of Marine Science 22(4): 900-925.
Petucli, E. J. 1987. New Caribliean molluscan launas. CERF, Charlottesville, \A. 1.54 -t- A4 p.
Ponder, W. F. 1970. A new archibenthal species of Fasciola- riidae from New Zealand, Journal of the Malacological Society of Australia 2(l):l-5.
Ponder, W. F. 1970a. The morphology of Alcithoc arahka (Gastropoda: Volutidae). Malacological Review 3: 127- 165.
Ponder, W. F. 1970b. Some aspects of the morphology of four species of the neogastropod famiK Marginellidae w itli a discussion of the evolution of the toxoglossan poison gland. Journal of the Malacological Societ\ of .Australia 2(1):55-81.
Ponder, W. F. 1972. The morphology of some mitriforni gastropods with special reference to their alimentar\ and reproductive systems (Neogastropoda). Malacologia 11(2): 295-342.
Ponder, W. F, 1973. .A re\ie\\ of the .\ustralian species of Penion Fischer (Neogastropoda: Buccinidae). Journal of the Malacological Societx of Australia 2(4)401-428
Pontler, W. F. 1973a The origin anil evolution of the Neo-
gastropoda. Malacologia 12(2):295-338.
Ponder. VV. F. and T. A. Darragh. 1975. The genus Zcniira H. and A. Adams (Mollusca: Neogastropoda). Journal of the Malacological Society of Australia 3(2):S9-I09.
Ponder, W. F. and A. Waren. 1988 Cla.ssification of the Caenogastropoda and Heterostropha — a list of the family- group names and higher ta.xa In: Ponder, W. F. (ed.). Prosobranch phvl(igen\: proceedings of a svmposium held at the 9th International Malacological Congress. Edin- burgh, 1986. Malacological Re\iew, Supplement 4:288- 328.
Sohl, N. F, 1987. Oetaceous gastropods: contrasts between Tethys and the temperate provinces Journal of Paleon- tology 61(6):1085-1111.
Taylor, J. D. 1978. The diet of Bucciiunn iindutuni and Ncptunea antiqua (Gastropoda: Buccinidae) Journal of ConchologN, London 29(6):309-318
Taylor. J. D., N. J. Morris, and C. N. Taylor 1980, Food specialization and the evolution of predatorv prosobranch gastropods. Palaeontolog) 23(2):375-409,
Thiele, J 1929 Handbuch der systematischen Weichlier- kunde, Gustav Fischer, Jena l(l):l-376.
Wenz, W. 1941-1943. Gastropoda. In: Schidewolf. O H (ed ) Handbuch der Palaozoologie Band 6. Gebriider Brontraeger, Berlin, Teil 5, 6:961-1506.
V\ ilkinson, L. 1988. SYSTAT: the system for statistics. SYS- TAT, Inc., Evanston, IL.
THE NAUTILUS 104(4):130-144, 1990
Page 130
BeUascintilla parmaleeana New Genus and Species from the Tropical Eastern Pacific, with a Review of the Other, Ventrally Notched Galeommatid Genera (Bivalvia: Galeommatacea)
C. Cliflon Coney
Los Angeles (,'ounty Museum of Natural History 900 Exposition Boulevaril Los Angeles, C:A 90007, USA
ABSTRACT
BeUascintilla parnuikcdna. new genus and species, is de.seribetl from tlie tropical eastern Pacific. It differs from nivariscintilla riiaoria Powell, 1932, in the morpholog)' of the cardinal teeth, as well as the internal crenulation of the ventral margin of the valves, prominent exterior radiating sulcus, sculpture of corn- marginal striae, and in shell ultra.structure.
Four other ventralK notched galeommatids are redescribed on the basis of shell characters and shell ultrastructure: Vas- coniella jeffreysiana (F'ischer, I<S73), from the northeastern Atlantic, Divariscinlilla rnaoria Powell, 1932, from New Zea- land, Tryphonitjax lepidojornm Olsson, 196L and T. mexi- cantts (Berr\, 1959) from the tropical eastern Pacific, The gen- eral shell characters of the latter two species indicate these to be more closely allied with Caleomma.
Divariscinlilla yoyo Mikkelsen and Bieler, 1989, and D. trog- lodytes Mikkelsen and Bieler, 1989, lack a ventral notch and are reassigned to the genus Phhjctaenachlamys Popham, 1939, based on shared characters of internal shell and morphology of shell, hinge, ligament, mantle, and ctenidia; however, the "flower-like organ" has not been reporleil in Phlyctaciuichlinn- i/.s.
.^('1/ words: ventrally nolthed galeonunatids; s\slematics; anatomy; shell ultrastructure; Phlyctacnachlamys.
INTRODUCTION
Galeommatid bivalves are small and easily overlooked, particularly because the living animals are often com- mensal with other kinds of animals, such as living at- tached to the walls of stomatopod burrows. Stomatopod burrows have not been adequately sampled for associated species of Mollusca. galeommatid shells, however, are reasonably well represented in museum collections and have morphological characters that enable the deHnition of genera and species based on shell characters alone. One group of galeommatids has tlie slicll ventrally notched in one or both valves. Until now the number of species
known with this feature is four, and a total of three generic taxa have been introduced to accommodate them.
The objective here is to describe a new monotypic genus and species that is broadly distributed throughout the Panainic Province. This necessitated comparison \\ ith other ventrally notched galeommatids from the same faunal region and other regions of the world. The total number of taxa is sufficiently small to enable a full review of all species.
I have included descriptions of shell ultrastructure in addition to the conventional shell characters, providing an additional character set. The information derived from shell ultrastructure provides finer distinctions in support ol the classification adopted here.
MATERIALS AND METHODS
Specimens of Vasconiclla jeffreysiana. Divariscintilla maoria, Tryphomyax Icpidoformis, T. rnexicaniis and of BeUascintilla parmaleeana (LACM paratypes 2447 and 2448), were inounted on stubs, gold coated and ex- amined with a Cambridge 360 scanning electron micro- scope (SEM) set at 20 kilovolts and a working distance of 10 mm. The holotvpe of B. parmaleeana (LACM 2446) was examined uncoated with SEM set at 2 kilovolts and a working distance of 6 mm.
Onl\' a single \al\e of each genus was examined for shell ultrastructure because the ventrally notched gal- eommatid species are rare and few speciinens are avail- able for study. Examination of shell ultrastructure was conducted on adult valves that w ere broken radialK from hinge line to ventral edge. It was generalK possible to follow each of the shell layers described from umbo to ventral margin. Individual shell lavers were observed at magnihcations of .5,000 x and 10,000 x. Photomicro- graphs were made in the central region of the shell that contained all the shell lavers. Measurements of shell thickne,ss were made in the central region of the shell.
C. C. Coney, 1990
Page 131
Table 1. Comparison of sliell characters of Vasconiella. Dicariscintilla. Tryplmmuux. and Bcllasciiitilla
|
(.liaraclcr |
Vaudiiiclla |
Dirarixciiililla |
Tiiipli |
iiniyax |
Bc'llasrintilla |
|||||
|
Ventral notch |
Ijresent on rig |
ht \alve |
present on |
both |
valves |
present on |
both |
val |
ves |
present on both \alves |
|
Valve congruence |
grcatK inequivalve |
eriui\alve |
equivalve |
slightlv inequivalve |
||||||
|
Exterior sculpture |
right smooth. |
left with |
smooth |
cancellate |
commarginal striae |
|||||
|
commarginal striae |
||||||||||
|
Nnd-\aKc sculpture |
two radiating |
rilis fused |
radiating ri |
b |
radiating ri |
lb bonne |
1 In |
two radiating ribs |
||
|
In suture |
sulci |
fused bv suture |
||||||||
|
Interior sculpture |
fine rihlets on |
margm |
niinuti'K granul |
ate |
radiating ri |
lbs |
crenulate margin |
|||
|
Position ot beak 6; |
central |
anterior |
central |
anterior |
||||||
|
cardinals |
||||||||||
|
Cardinals t\pe |
tubercular |
tubert'ular |
tubercular |
cuniform |
||||||
|
no. left |
.■> |
I) |
2 |
■^ |
||||||
|
no. right |
1 |
1 |
1-2* |
2 |
||||||
|
Laterals |
||||||||||
|
no. left |
1 |
1 |
1 |
1 |
||||||
|
no. right |
1 |
0 |
1-2* |
2 |
||||||
|
Adductor |
unknow n |
unknown |
unknouii |
isomvarian |
||||||
|
Ligament |
unknown |
amphidetic |
resilium |
resilium |
■ Bcflects a species level diHercntiati
using a vertical point-to-point feature. Characterization of inclividual la\ers of siiell ultrastructure follows stan- dards defined b\ Charter and Clark (1985). Shell dimen- sions were measured using a Zeiss zoom stereomicroscope with optical reticle.
For consistency, revised descriptions are given for each species.
The following institutional abbreviations are used: ANSP, Academy of Natural Sciences of Philadelphia; CAS, California Academy of Science; LACM, Los An- geles Count}' Museum of Natural History; NMNZ, Na- tional Museum of New Zealand; SDNHM, San Diego Natural History Museum; SMNH, Swedish Museum of Natural History; I'SNM, National Museum of Natural History.
SYSTEMATICS
Bivalvia Linnaeus, 1758
Heterodonta Neumayr, 1884
Veneroida H. & A. Adams, 1856
Galeommatacea Gra\, 1840
Galeommatidae Gray, 1840
[= Galeomatidae Nordsieck, 1969]
[= N'asconiellidae Scarlato and Starobogatov, 1979]
Chavan (1969) treated the family Galeommatidae with- out subfamilial division, recognizing 24 genera (five of these questionably, with four others pronounced genera dubia). and 10 subgenera. Of these, only three genera possess a ventral notch at mid-valve position in one, or more commonly, both valves.
The new species described herein tliffers at the generic level. Its description follows the review of other \entrall\ notched galeommatids: Vasconiella jeffreijsiana (P. Fi- scher, 1873), Divariscintilla maoria Powell, 1932, Try-
phomyax Icpidofunnis Olsson, 1961, and T. mexicaniis (Berrv, 1959).
Ke\ to the \entrall\ notched Galeommatidae: (See table 1 for additional details)
1 . Shell ventrally notched at mid-valve length in right valve onK, left valve orbicular in profile
Vasconiella
Both valves ventrally notched at mid-valve length 2
2. Shell exterior smooth, unsculptured, with single, small mid-valve rib; ventral notch broad and shal- low Divariscintilla
Shell exterior sculptured, mid-valve rib promi- nent, ventral notch narrow and deep 3
3. Shell exterior sculptured with riblets and com- marginal striae giving the exterior a cancellate appearance, mid-valve rib bordered on either side
by luinute sulci Tryplwniyax
Shell exterior sculptured with fine commarginal striae only, mid-valve rib composed of two ribs fused together by a medial suture . . . Bellascintilla
Vasconiella Dall, 1899
Type species by original designation: Hindsia jeffrey- siaria P. Fischer, 1873. The genus is monot\pic.
Diagnosis: Highly inetjuivalve with left valve larger than right valve. Shell ventrally notched at mid-valve length in right valve onl\ , left \alve orbicular in profile. Tw o ribs, fused by a suture, ascend from rnid-\ alve notch of right valve and rise to middle of central slope, left \al\e without such sculpture. Cardinal teeth tubercular.
Page 132
THE NAUTILUS, Vol. 104, No. 4
Figures 1-6. Vasconiella jcfrcysiana yl\ Fisclii-r, l.bT.i;. SMNH uiicataloged, Sagrt-s, Algarve Prov,, I'ortiigal, 17-33 m 1. Exterior of left valve, length 3.4 mm, Poiital do.s Corvos, 17-22 m. 2-6. Poiila ilos Caminos. 23-33 m. sand 2. Exterior of right \alve, length 3..5 mm. .3. Interior of left valve, length 4.0 mm 4. Interior of right valve, length 3 S iiiiii ... Hinge of right valve, .scale bar = 200 Mm. 6. Hinge of left valve, scale bar = 200 Mm-
C. C. Conev, 1990
Page 133
one in right valve, two in left valve. One posterior lateral tooth present in each valve.
Remarks: The type species of Vasconiella was origi- nalK described in the genus Hindsia Deshayes, 1858, not H. and A. Adams, 1853, in which the type species has a geologic range of Paleocene to L'pper Eocene. Hindsia was replaced bv Hindsiella Stoliczka, 1871, and assigned to the Sportellidae by Dal! (1899:876). The ge- nus Vasconia Fischer, 1873, was another unnecessary new name for Hindsia; Fischer (1887) corrected this error. Dai! (1899:875) was the first to recognize the need for generic separation of "Vasconia" jeffreysiana; the name Vasconiella was proposed in a provisional classi- fication scheme without discussion.
Vasconiella jeffreijsiana (P. Fischer, 1873) (figures 1-6, 31, 35)
Hindsia jeffreijsiana P. Fischer, 1873:83, pf 2, fig. 8; 1SS7:
1032-1033, fig. 776a,b. Scintilla crispata P. Fischer, 1873:83, pi. 2, fig. 7; P. Fischer,
1874:220; P. Fischer, 1878:178; Hildago, 1917:631; Aart-
sen, 1982:125, Vasconia jeffreijsiana; P. Fischer, 1874; de Folin and Perier,
1878:351; P. Fischer, 1878:178; Hildago, 1917:727. Lcpton lepisma Monterosato. 1878:314; Waren, 1980:46; .\art-
sen, 1975:467; 1982:125. Vasconiella jeffreijsiana; Dall, 1898:875; Pasteur-Humbert,
1962:53, pi. 19. fig. 75; Montero Aguera, 1971:58; Kisch,
1958:21-24, fig. 1, pi. 3; Nordsieck, 1969:91, pi. 14, fig.
51.30; Chavan, 1969:537, figs. 35-7a,b; Aartsen, 1975:466-
467; 1982:125; Bruggeman-Nannenga, 1975:14; Dekker,
1975:466; Mienis, 1975:441; 1976:522; Verduin, 1975:422;
Bouchet, Danrigal, and Huvghens, 1978:126, pi 5, fig. 17;
Montero Aguera. 1971:58-.59; Cornel, 1982:36-43. figs. 2-
5; Mikkelsen and Bieler, 1989:189. Solecardia (Scinldlorbis) crispata; Montero Aguera, 1971:223-
224.
Material examined: SMNH uncataloged, Pontal dos Corvos, Sagres, Algarve Prov., Portugal (37°01.3'N, 08''58.3'W), 17-22 m, base of cliff, May 1988, one left valve. SMNH uncataloged, Ponta dos Caminos, Sagres. Algarve Prov., Portugal (37°02'N, 08°52'W), 23-33 m, sand. May 1988, five right valves, one left valve. SMNH uncataloged, Sagres Harbor, Algarve Prov., Portugal (37°00.6'N, 08°55.6'W), 9-15 m. May 1988, one left valve. SMNH uncataloged, Baia Baleeira, Sagres, Algarve Prov., Portugal (37°00J'N, 08°55.0"W), 12-17 m, sand, May 1988, one right valve.
Description: Right and left valves highly disparate, in- equivalve by virtue of deep notch in ventral shell margin of right valve; ventral shell margin of left valve subcir- cular. Right valve attaining 4.2 mm in length and 3.0 mm in height; left valve larger, attaining 5 4 mm in length and 4.6 mm in height. Exterior of right valve smooth except for growth rings and two ribs joined to- gether by suture radiating from umbo, becoming more raised where joining notch of ventral shell margin. In- terior of right valve with corresponding sulcus radiating
of ventral shell margin. Left valve subcircular in outline. Exterior surface smooth, with many evenK- spaced corn- marginal striae on shell exterior from middle of valve to valve margin. Fine radiating riblets faintly impressed on ventral margin of interior of right valve, strongly im- pressed on ventral margin of interior of left valve. One tubercular cardinal tooth and one short posterior lateral tooth in right valve; two cardinal teeth in left valve, anterior cardinal wedge-shaped, posterior cardinal tu- bercular; one short posterior lateral tooth.
Shell ultrastructure (figure 35): Shell thickness of spec- imen studied 35 /um, consisting of five distinct layers. Exterior layer of thin, blocky simple prismatic structure, underlain by layer of fine-grained homogeneous struc- ture; median and thickest layer of crossed-lamellar struc- ture, underlain by fine-grained homogeneous structure; innermost layer of thin blocky simple prismatic structure.
Distribution: Bay of Biscay and Mediterranean Sea (Franc, 1960) to Morocco (Pasteur-Humbert, 1962), north to Plage de I'Aber, Kerfany les Pins and Quiberon on the French Atlantic coast (Aartsen, 1982).
Remarks: The notched right valve of Vasconiella jef- freijsiana was described b\' P. Fischer (1873) as Hindsia jeffreijsiana while the unnotched left valve also was de- scribed by P. Fischer (1873) as Scintilla crispata. Kisch (1958) reported the discovery of to disparate valves joined together in a single specimen; however, he did not as- sociate the name S. crispata with the left valve and described and illustrated the left valve as if for the first time. Cornet (1982), in a partial synonymy of Vasconiella jeffreijsiana, was first to recognize and associate the left valve with the original description of S. crispata.
Cornet (1982) illustrated the hinge of both left and right valves and provided additional description of the hinge and exterior "deposit", but stated in error that "there are no true lateral teeth." Scanning electron pho- tomicrographs of the hinge clearh show the presence of a short posterior lateral tooth in the right \alve (figure 5), and a short posterior lateral tooth in the left valve (figure 6). The single cardinal tooth of the right valve fits beneath the two cardinal teeth of the left valve, and the lateral tooth of the left valve fits beneath the lateral tooth of the right valve, forming a ver\ effective fulcrum and counterlocking hinge. SEM views of the mid-valve ridge (figure 31) show it to be two ridges fused together by a radial suture.
The anatomy of Vasconiella jeffreijsiana was de- scribed in detail by Cornet (1982). No positive evidence for commensial association with stomatopods has been documented; however. Cornet (1982) noted that the dis- tribution of Vasconiella jeffreijsiana was congruent with that of Lysiosquilla eusehia (Risso, 1816).
DivariscintUla Powell, 1932
Type species by original designation: Dirariscintilla
maoria Powell, 1932 The genus is monotypic.
C. C. Coney, 1990
Page 135
Diagnosis: Both valves veiitralK notcheci at inici-valve lengtli, ventral notch broad and shallow. Shell exterior smooth, unsculptured, with single, small miil-val\e rib beginning at mid-valve notch and ending on central slope. Two tubercular cardinal teeth in right valve, left valve without teeth.
Divariscintilla maoria Powell, 1932 (figures 7-12, 32, 36)
DiiariscititiUa maciria Powell, 1932:66-67, pi. 6, fig. 1 [liolo- tvpe, .\uckland Museum]; 1962122; Judd, 1971;343-353, figs. 1-7; Morton. 1975:36.5, 368; 1976:32; Mikkelsen and Bieler, 1989:175-195,
\ asconicUa {Divariscintilla) maoria; Chavan, 1969:537; Pow- ell, 1976:126.
Material examined: NMNZ M21965, Cheltenham Beach, Auckland, New Zealand, from Lysiosqiiilla spi- nosa burrows, one left valve, one right valve, and two specimens with paired valves.
Description: Shell equivalve, inequilateral. The second largest ot the ventralK notched galeommatids with both valves attaining 6.0 mm in length and 4.9 mm in height. Anterior end shorter than posterior as defined by notch on mid-ventral margin. Fine, week rib radiating from umbo to ventral notch in both valves, otherwise shell exterior w ith commarginal growth lines divaricating at radiating rib. Interior of valves minutely granulate, shell margin smooth; weak interior sulcus radiating from beak cavity to ventral notch and corresponding to external radiating rib. Ligament amphidetic, mostly posterior to beak supported by n)mphs. Hinge of right valve with one tubercular cardinal tooth, anterior to large resilium (figure 11). Left valve lacking cardinal teeth, narrow- horizontal resilifer under posterior side of beak; lateral tooth posterior to beak, terminating at terminus of nymph.
Shell ultrastructure (figure 36): Shell thickness of spec- imen examined 25 nm. Shell consisting of three distinct layers. Exterior shell layer of fine grained homogeneous structure; median and thickest layer consisting of inter- sected crossed platy structure; interior shell layer of ir- regular simple prismatic structure.
Distribution: Scattered shells have been found through- out New Zealand (Judd, 1971).
Remarks: Powells (1932) description, although de- tailed, lacks mention of the follow ing features. The lig- ament is described as being amphidetic without mention of a nymph. The ligament is primarily posterior to the beak where it is supported by a nymph (figure 12), yet the ligament does pass between the beaks, terminating slightly anterior to them where it is supported by a small
nymph Additionalh , no mention is made of the lateral tooth of the left valve, the graindar interior shell surface, or the weak external rib that radiates from umbo to ventral notch (figure 32), with a corresponding sulcus on interior of valves.
Judd (1971) documented the anatom\. behavior, and commensal relationshij) of Divariacintilta maoria with stomatopods.
Tryphamyax Olsson, 196]
Type species: Tryphamyax Icpidoformis Olsson, 1961 by original designation. The genus Tryphoiiiyax pres- ently contains two species: T. Icpidoformis Olsson, 1961, and T. tnexicaniis (Berry, 1959).
Diagnosis: Shell quadrate or subovate with a prominent radial mid-valve rib from mid-valve notch to umbo bound on either side b\ minute sulci. Cancellate sculpture of exterior produced by radial riblets and commarginal stri- ae. One or two tubercular cardinal teeth in right \alve, two in left valve. One or two lateral teeth in right valve, one lateral tooth in left valve.
Tryphamyax lepidafarmis Olsson, 1961 (figures 13-16, 33)
Tryi>hi)iuyax Icpidoformis Ol.ssoii. 1961:240-241, pi 36. figs.
4, 4a [hcilotvpe, ANSP 218922]; Keen, 1971: 133- 135. fig.
308; Bernard, 1983:30. Tryphamyax Icpidoformis Incvis Olsson, 1961:241. pi, 36, figs.
7, 7l)'lholotype. ANSP 218923],
Material examined: LACM 77-144,4, Punta Chame, Golfo de Panama, Panama (08°41'N, 79°39'W), shallow dredging, two left valves. LACM 62-22.1, Bahia Cholla, W of Puerto Pefiasco, Sonora, Mexico (31°19.6'N, 113°37.7'W), intertidal screenings, one right valve.
Description: Shell equivalve, inequilateral. Outline of shell rectangular. Anterior of valves shorter than poste- rior as defined by notch on mid-ventral \alve margin Wide, pronounced rib radiating from umbo to \entral notch in both valves (figure 33). Exterior of valves with regularlv spaced riblets radiating from umbo and densely covered with thin, closely spaced commarginal multi- costae. Interior of valves with regularly spaced, pro- nounced ribs radiating from umbo cavity, becoming slightly divaricated anteriorly; weak interior sulcus ra- diating from beak cavity to ventral notch and corre- sponding to external radiating rib. Ligament internal. Hinge of right valve with one large tubercular cardinal tooth and a smaller lamellar cardinal tooth anterior and dorsal to larger tooth; two very short lateral teeth located posterior to cardinal teeth; ventral lateral tooth descend-
Figures 7-12. Divariscintilla maoria Powell, 1932. NMNZ M.21965. Cheltenham Beach, Auckland, New Zealand, from Lysiosqiiilla spinosa burrows, 7. Exterior of left valve, lengtli 6 1 mm. 8. Exterior of right valve, length 6.0 mm 9. Interior of left valve, length 5 0 mm, 10. Interior of right valve, length 5,0 mm 11. Hinge of right valve, scale bar = 500 /im. 12. Hinge of left valve, scale bar = 200 ^m
THE NAUTILUS, Vol. 104, No. 4
Figures 13-16. Tryphomyax lepidofurmis Olsson, 1961. 13-14. 16. L.\CM 77-144 4. Punta t:lia.ne, Golfo dv Panama, Panama 13. Exterior of left valve, length 5.4 mm. 14. Interior of left valve, length 5.4 mm. 15. LACM 62-22.1, Bahia Cholla .Sonora Mexico. Hinge of right valve, scale bar = 200 nm 16. Hinge of left valve, scale bar = 200 A^m
Figures 17-20. Tryphomyax mexicanus (Bcrrv, 1959) 17. L.ACM 65-82.1, N end Isla CeraKo, Culf of California, Raja California Sur, Mexico, left valve exterior, length 5.7 mm. 18. 20. L.\CM 71-22.1, S of P.inta .\reim. Gulf of California, Raja California Sur, Mexico. 18. Interior of left valve, length 29 ■mn 19. L.\CM 66-21 3. from off Punta .\rena, Culf of California. P.ija California Sur, hinge of right valve, scale bar = 200 ^m 20. Hinge of left valve, scale bar = 200 nm
C. C. Conev, 1990
Page 13'
ingsharpK from beak, dorsal lateral tooth approxiiiiateK parallel to hinge margin; obscure resilifer posterior to tubercular cardinal tooth. Left valve w ith two cardinal teeth, anterior cardinal tooth tubercular, separated from posterior cardinal tooth by curved fossa; posterior car- dinal tooth C-shaped, curved anteriorly; posterior lateral tooth descending sharply from beak, separateil from pos- terior cardinal tooth by resilifer forming triangular fossa with apex reaching beak.
Distribution: A single valve is reported here from the head of the Gulf of California. This may have been due to a labeling error, as all other records are from Panama.
Remarks: This species is one of the rarest bivalves in the Eastern Pacific. It was reported b\ Olsson (1961) to occur in association with "worm tubes" Anatomy, be- havior, and reproduction are unknown.
Although Bernard {1983) listed Tryphoinyax Icpido- formis Olsson as a synonym of T. mexicanus (Berry), both taxa are recognized here as distinct species. Com- parisons with T. mexicanus are given below.
Tryphomyax mexicanus (Berr\, 1959) (figures 17-20, 37)
Caleomma mexicaiuis Berry, 1959:108-109 [hi)li>t\pt', CAS 043981, paratvpe, SDNHM 42813]; Hertz, 1984:18, fig. 35.
Tryphomyax mexicanus: Keen, 1971135, fig. 308; Bernard, 1983:30,
Material examined: LACM 69-21.4, W side Isla Mir- amar, S of Puertecitos, Gulf of California, Baja Califor- nia, Mexico (30°04,8'N, 114°33.0'W), 15-26 m, sand, one left valve. LACM 69-22.3, W of Isla San Luis, S of Puer- tecitos, Gulf of California, Baja California, Mexico (29°57.80'N, I14°28.0'W), 26 m, sand, right valve (bro- ken for shell ultrastructure after measurement). LACM 85-21.1, Juncalito, Gulf of California, Baja California Sur, Mexico (25°53'N, 1 1 1°20.5' W), beach drift, one right valve, one left valve. LACM 65-82.1, off N end Isla Ceralvo, Gulf of California, Baja California Sur, Mexico (24°23'N, 109°55.5'W), 9 m, one left valve. LACM 66- 21.3, off Punta Arena, Gulf of California, Baja California Sur, Mexico (23°32'N, 109°28'W), 18-37 m, sand, one right valve. LACM 71-22.1, Los Tezos Ranch, 1.5 mile S of Punta Arena, Gulf of California, Baja California Sur, Mexico (23°31'N, 109°00'VV), 9 m, one left valve.
Description: Shell equivalve, inequilateral. Largest of the ventrally notched galeommatids with valves reaching 6.4 mm in length and 4.0 mm in height. Outline of shell oblong and rounded, not rectangular, .interior of valves shorter than posterior as defined b> notch on mid-\entral valve margin. A weak rib radiating from umbo to ventral notch in both valves. Exterior of valves with irregularly spaced riblets radiating from the central slope to the ventral margin; denseK co\ered w ith thin, closely spaced commarginal multicostae. Interior of valves smooth, ex- cept ventral margin, which is crenulate with small ra-
diating riblets. Hinge of right valve with one large tu- bercular tooth, and posterior fossa for resilifer, both located under beak; one large lateral tooth posterior to resilifer. Left \alve with two cardinal teeth, posterior cardinal tooth tubercular, arising from directK under the beak; anterior cardinal tooth lamelliform, descending at an angle from beak. Lateral tooth of left valve hori- zontal and parallel to dorsal hinge line.
Shell ultrastructure (figure 37): Shell thickne.ss of spec- imen examined 59 ^m, with a single distinct layer, con- sisting of ver\ fine complex crossed-lamellar structure.
Distribution: Throughout the Gulf of California. Pre- viously reported only from the head of the Gulf of Cal- ifornia (Berry, 1959; Keen, 1971). The distribution is here extended south to Punta Arena, Gulf of C:alifornia, Baja California Sur, Mexico. The more extensive distribution cited by Bernard (1983) from the head of the Gulf of California to Panama was a result of his synonomy of T. lepidoformis with T. mexicanus.
Remarks: This species differs from T. lepidoformis in profile, being rounded rather than rectangular, in both external and internal shell sculpture, and in having a different hinge structure. The posterior lateral teeth in the right valves are different in both number and relative size, T. nuwicanus having a single large posterior lateral (figure 19 truncates prior to posterior terminus of lateral tooth due to accidental shell breakage) whereas T. lep- idoformis has two small short posterior lateral teeth in the right valve. The primary distribution is more north- ern than that of T. lepidoformis. the records limited to the Gulf of California, .\natomy, ecolog) , beha\ior, and reproduction are unknown.
Bellascintilla new genus
Type species, here designated: Bcllascinlilla parma- leeana new species. The genus is monotypic.
Diagnosis: Shell subtriangular in outline with beaks an- terior. Two distinct ribs fused together by medial suture arising from mid-valve notch, terminating abruptK' on umbo. Shell sculptured w ith fine commarginal striae that ascends towards mid-\al\e ribs. Cardinal teeth cunei- form, two in each valve. One posterior lateral tooth in left valve, two posterior lateral teeth in right valve. Re- silifer between cardinal teeth and lateral teeth.
Etymology: The name is a Latin compouiul derived from scintilla, spark, and bella, beautiful.
Remarks: The smallest of the ventralK notched galeom- matids, the shell attaining 4.5 mm in length and 3.5 mm in height. Bellascintilla (figure 38) differs from Divar- iscintdla (figure 36) in shell ultrastructure (thickest la\er of crossed lamellar structure underlain by fine grained homogeneous structure rather than thickest la\er of in- tersected crossed platv structure underlain by irregular simple prismatic structure as in Dicariscinlilla). being more like that of Vasconiella (figure 36); in exterior shell
Page 138
THE NAUTILUS, Vol. 104, No. 4
Figures 21-24. Bellascintilla parmaleeana new species. Holotype, LACM 2446, off Bahia Herradura, Puntarenas Province, Costa Rica. 21. Interior of left \alve, length .3 2 mm. 22. Hinge of left valve, scale bar = 200 fin\ 23. Interior of right valve length 3 1 mm. 24. Hinge of right valve, scale bar = 200 ^m.
.sculpture (fine commarginal striae, with small undulating ribs along posterior dorsal margin and ventral margin internally crenulate rather than essentially smooth, fea- tureless sculpture as in Divariscintilla). in form and num- ber ot the mid-valve ribs (two fuseil together by suture rather than a single small rib as in Divariscintilla); and in the hinge teeth (cuniform rather than tuberculiform). Based on similarity of shell ultrastructure, and the for- mation of the mid-valve ridge, Bellascintilla also rec|uires comparison to Vasconietla. These genera differ in left valve profile (triangular and ventrally notched rather than suborbicular and lacking a ventral notch as in Vas- coniella), and in the mor|5hology of their hinge teeth (cuneiform rather than tuberculiform). Tryphomyax and Bellascintilla do not share any of the features studied here other than the presence of a ventral iiotcfi.
The discovery of a new species that shares with the type species of Divariscintilla the presence of a notch in the ventral margin of both valves inilialK suggested that Divariscintilla includes species possessing this specific character. Comparison of shell ultrastructure characters, and the formation of the mid-vaKe ridge, re\<'al that Bellascintilla is more clo.sely related to Vasconiella than to Divariscintilla, despite the initial similarity of shell form between Bellascintilla and Divariscintilla. The hinge teeth of Bellascintilla are cuniform rather than
tuberculiform as in Vasconiclla, Divariscintilla and Trij- phomijax suggesting that possession of a notch in the ventral valve margin could be convergent, or that the cuneiform teeth of Bellascintilla evolved from tuber- culiform teeth of its ancestor.
Bellascintilla parmaleeana new species (hgures 21-30, 34, 38)
Type locality: Off Bahia Herradura, Puntarenas Prov- ince, Costa Rica (9°38.S'N, 84°40.8'\\'). 37 m (R/V SEARCHER station 451; LACM station 72-54).
Type material: Holotype: L.\C"M 244(i; articulating pair of valves, left \al\e length 3.2 mm (figures 21-22), right valve length 3 1 nun (figures 23-24), height both valves 2.4 mm.
LAC>"M 2447, five paratvpes, Isla ilel Cano, Puntarenas Province, Costa Rica (8°44.0'N, 8.3°52.5'\V'), 12 m, sand, R/V SEARCHER (LAC:M station 72-H4): specimen a. left valve, length 3.6 mm, height 2.6 mm (figure 25); specimen /), left valve, length 4.1 mm, height 3.4 mm (figures 26-27); specimen c, right vaKc, length 3.1 mm, height 2.4 mm (figures 28, 34); specimen (/, right valve length 3.4 mm, height 2.5 mm; specimen c, right valve length 3.5 mm, height 2.9 mm.
C. C. Conev, 1990
27 3
Figures 25-30. Belhscintilla parmaleeana new spec.es. Paratypes, 25-28. LAC;M 244, Isla de t.ano I untarenus 1 r,.^■■ ce Costa Rica, 25. Specimen a. exterior of left valve, length 3.6 mm 26. Specimen /.interior left valve, ler.^th 1 1 ""•'_ -^ ' • ^'^ ""' b. hinge of left valve, scale bar = 200 ^m. 28. Specimen c, exterior of right valve, length ,1 nun 2«)-3( . 'A M 2^4S, '; '<- ' " El Tule and Rancho Palmilla, (U.lf of California, Raja CaHfornia Snr, Mexico. 29. Interior oi nght valve, length 4 .. mm JO. Hmtc of right valve, scale bar = 200 ^m
LACM 2448, paratv pe, between Rancho Ei Tule and Rancho Palmilla, Gulf of California, Baja California Sur, Mexico (22°58'N, 109°48'W), 18-37 ni, sand (LACM sta- tion 66-17), right valve, length 4.5 mm, heiglit 3.5 mm (figures 29-30).
LACM 2449, paratype, Playa Nancite, N side Golfo de Papaguavo, Parque Naeional Santa Rosa, Guanacaste Province, Costa Rica (10°48'N, S5°42'\V), beach drift
(LACM station 86-26). left valve, length 3.1 mm. height 2.5 mm.
LACM 2450, seven paratypes, Punta Cfiame, Golfo de Panama, Panama (08°4rN, 79°39'\V), shallow dredging (LAC;M station 77-144), specimen a, right valve, length 4.2 mm, height 3.3 mm; specimen h. right valve, length 3 4 nmi, height 2.7 mm; specimen c, right valve, length 3.5 mm, height 2 6 nmi; specimen il. right valve, length
Page 140
THE NAUTILUS, Vol. 104, No. 4
Figures 31-34. Comparison of mid-valve ribs. 31. Vasconiella jeffreijsiana. SMNH uncataloged, scale bar = 500 ^m. 32.
Diiuriscintillii maoria. NMNZ M. 21965, scale bar = 500 /zm. 33. Tnjphoniijax lepidoformis, LACM 77-144.4, scale bar = 500 Mill .31-. Bellascinlilla piirmalceana new species, paratype, LACM 2447, specimen c, scale bar = 500 /jni.
3.3 mm, height 2.7 mm; specimen e, right valve, length 2.9 mm, height 2.3 mm; specimen /, left valve, length 4.1 mm, height 3.1 mm; specimen g, left valve, length 3.5 mm, height 2.9 mm.
LACM 24.51, paratype, N side Isla Salango, Manabi Province, Ecuador (01°35.5'S, 80°53.4'W), 6-12 m, under rocks and coral (LACM station 80-65), left valve, length 2.8 mm, height 2.1 mm.
USNM 859410, paratv pe from type locality, right valve, length 2.7 mm, liciglit 2 0 mm.
Description: Shell ineiiuivalve, inequilateral, very small (to 4.5 mm). Ligament an internal resilium. Left valve slightK longer than right valve. Left valve with two cuneiform cardinal teeth, posterior cardinal low, apex directly under beak, anterior cardinal with ajiex anterior to beak, widening as it tlesceiids, two cardinal teeth sep- arated by narrowly radiating fossa. Hesilifer separating cardinal teeth from posterior lateral teeth in both valves. Left valve with single downward curving lateral tooth. Right valve with two radiating cuneiform cardinal teeth, apices fused immediateK below beak, wiilening as they descend. Teeth separated by deep fos.sa that widens as it descends. Two posterior lateral teeth in right valve posterior to resilium and cardinal teeth. Posterior and
anterior adductor muscle scars equal in size, posterior adductor muscle scar located higher in valves than an- terior adductor scar. V'entral margin of shell in both valves internally crenulate. Mid-ventral notch pro- nounced giving rise to a raised triangular fold that as- cends dorsalK to umbo. This interior, raised triangular fold corresponds externally to two ribs joined together by suture that arises from mid-ventral notch on ventral margin of exterior shell \ aK e and ascends towards umbo. The fold truncates abruptly within 0.3 to 0.5 mm of umbo. Exterior sculpture of both valves \\ ith fine com- marginal striae. Small undulating ribs radiating along posterior dorsal margin of shell, less developed along anterior shell margin.
Shell ullrastriicture (figure 38): Shell thickness of spec- imen examined 37 /jm, consisting ot tour distinct lavers. Exterior laver of ver\ thin, blocky, simple prismatic structure, underlain In layer of fine grained homoge- neous structure; median, thickest la\'er consisting of crossed lamellar structure, underlain by layer of fine grained homogeneous structure.
Distriliution: Hancho El Tule and Rancho Palmilla, Gulf of California, Baja California Sur, Mexico (22°58'N,
C. C. Conev, 1990
141
Figure§ 35-38. Comparison of shell ultrastructure. Exterior surface at top. SEM views taken on central slope of valves. 35. Vasconiella jcffreysiana. SMNH uncataloged, scale bar = 20 Mm. 36. Divariscintilla maoria, NMNZ M. 21965, scale bar = 10 Mm. 37. Tnjphomyax mexicanus. LACM 59-22.3, scale bar = 20 M'n. 38. Bellascintilla parmaleeana new species, LACM 72-54 (from same lot as liolotype), scale bar = 20 ijm.
109°48'W) to Isia Salango, Manabi Province, Ecuador (01°35.5'S, 80°53.4'W).
Remarks: Known only from dead valves. This species is tfie smallest of the ventrally notched galeommatids. Information concerning the anatomy, reproduction, be- havior and commensal association, if any, of this bivalve is not available.
Etymology: Named in honor of Dr. Paul W. Parmalee, Director of the Frank H. McClung Museum and Pro- fessor of Zooarchaeology, Emeritus, Universit\' of Ten- nessee, Knoxville, Tennessee, who first inspired m\ in- terest in bivalve mollusks.
DISCUSSION
The family Vasconiellidae was erected by Scarlato and Starobogatov (1979) to accommodate the ventrally notched genus Vasconiella Dall, 1S99. Until the anatomy of more of the Galeommatidae has been studied and their relationships better understood, it seems premature to divide the Galeommatidae into subfamilies, much less additional families.
Tryphomyax shares with Vasconiella and Divariscin- tilla the tubercuiiform cardinal teeth. However, the shell ultrastructures of these three genera exhibit major dif- ferences. Although the shell ultrastructure of Galeomma Turton, 1825, is unknown, the shell of Tryphomyax has a basic morpholog)' suggesting affinity with Galeomma.
The presence of a ventral notch in the shell margin is the single shell character that genera Vasconiella. Di- variscintilla. Tryphomyax. and Rellascintilla share in common. What is the purpose of the \entral notch, and does it serve the same function in all four genera :■ Powell (1932) believed the ventral notch to be "a true ventral bvssus-sinus"; however, recent workers have demonstrat- ed no correlation between the ventral notch and the byssus. Cornet (1982) showed that the outer and middle mantle of the right side, adjacent to the v entralK notched right valve of Vasconiella. formed a deep indentation whereas the inner mantle fold was straight. In Divari- scintilla however, Judd (1971) reported that the mantle beneath the "'slit" (\entral notch) was not "incised." As the structure of the mantle beneath the notch differs in these two genera, a functional similaritv is regarded as unlikely. Judd (1971) demonstrated that the placement
Page 142
THE NAUTILUS, Vol. 104, No. 4
of the byssus on the foot of Divariscintilla was not an- atomically correlated with the location of the ventral notch. He further reported that the ventral notch was completely absent from juveniles less than 2-3 mm in length, and did not develop until the shell was 3.5-4.5 mm. Cox (1969) stated that the byssus of early postlarval stages of many bivalves serves as an anchor and prevents larvae from suffocating by suspending the juveniles above the level of .sediment deposition. Most bivalves lack a l)\ssus, or it is vestigial, in the adult stage. The devel- opment of the ventral notch in Divariscintilla late in its life cycle may be taken as indirect evidence against the ventral notch functioning to accommodate the byssus. Other galeonimatids that lack the ventral notch possess either a byssus or a byssal gland in the foot such as reported in Phlyctaenachlamijs b> Popham (1939). The function of the ventral notch in the four genera treated here remains unresolved.
Tryphomyax has the thickest shell (maximum thick- ness observed 59 ^m), and is composed of only a single layer, which is structurally different from that of the other three ventrally notched galeonimatids. Bellascin- tilla has a thinner shell (maximum thickness observed 37 /nmj, composed of four layers. The shell ultrastructure of Vasconiella is remarkably similar to that of Bella- scintilla, but is thinner (maximum thickness observed 34 /uni), and has an additional structural layer. Thus, Vas- coniella has the most complex shell ultrastructure of the ventralK notched galeonimatids studied to date. Divar- iscintilla has the thinnest shell of this group of galeom- matids (maximum observed thickness 25 nm), composed of three la\ers that are unlike the ultrastructures of the other ventrally notched galeommatid genera. None of these genera conform to the shell ultrastructure reported by Taylor, Kennedy, and Hall (1973) for two species of Scintilla in terms of numbers of shell layers, or their composition. In contrast, they report finding two layers, an outer layer composed of crossed lamellar structure and an inner layer of complex crossed lamellar structure in S'. aiveni Deshayes and S. rosea Desha\es (Taylor et ai. 1973). Further investigation into the comparative shell ultrastructure of galeommataceans is warranted, both to provide characters for phylogenetic analysis as well as to examine possible variation within and between populations and environments.
In addition to a strong similaritv in shell ultrastructure, Vasconiella and Bellascintilla show similarity in the for- mation of the mid-valve ridge, which in both genera exhibits two radiating ribs fused together with a suture between them. Prior to this stud\, Vasconiella, Divar- iscintilla and Tryphornijax were reported to have a single mid-valve radiating sulcus (Fischer, 1873; Olsson, 1961; Powell, 1932). Rased on shell ultrastructure and the for- mation of the fu.sed mid-vaKe ridges, Bellascintilla ap- pears to be more closely related to Vasconiella than to either Tryphomyax or Divariscintilla, despite the dif- ferences of shell shape, hinge teeth, and zoogeography.
Tlie hinge of Bellascintilla has some features in com- mon with the family Leptonidae (iray, 1S47 (e.g., cime-
iform cardinal teeth), and could conceivably be a prim- itive member of either family. It is therefore w ith some misgivings that 1 place Bellascintilla in the Galeom- matidae. A clearer understanding of systematic relation- ships within the Galeommatacea w ill result when more information concerning the anatomy and shell ultrastruc- ture of many of the genera becomes available. Because the definitions of the families in the Galeommatacea are not yet clarified (Ponder, 1971; Bernard, 1975), and in part because the anatomy and biology of Bellascintilla and Tryphomyax are unknow n, the relationships of these four genera are subject to change as additional data be- comes available.
I recognize a single species of Divariscintilla, the type species D. maoria. The two species described as Divar- iscintilla yoyo and D. troglodytes b\ Mikkelsen and Bie- ler (1989) are reassigned here to the genus Phlyctae- nachlamys Popham, 1939. They share with P. lysiusquillina Popham, 1939, the type species of Phlyc- taenachlamys, major conchological characters, including the unnotched ventral shell margin, hinge teeth and lig- ament morphology, shell ultrastructure, and anatomical characters including an internal shell, mantle morphol- ogy, and ctenidial morphologv (see Mikkelsen & Bieler, 1989; Popham, 1939). As in Phlyctaenachlamys lysios- quillina, P. yoyo and P. troglodytes have shells that are equivalve, inequilateral, oval, flattened, and roundK elongate anteriorK The hinge teeth and ligament are remarkably similar between the three species of Phlyc- taenachlamys, but are quite different than those of Di- variscintilla maoria Powell and BellascirUilla parma- leeana. The shell ultrastructure of Phlyctaenachlamys lysiosquillina is unknown. Mikkelsen and Bieler (1989) illustrate and describe the shell ultrastructure of P. ijoyo and P. troglodytes as "cross-lamellar, with thin homo- geneous layer on either side". This is somew hat similar to the ultrastructural arrangement of Vasconiella and of Bellascintilla, but is very different from the ultrastruc- tural arrangement of Divariscintilla, and even more so from that of Tryphomyax. The shell of Phlyctaenach- lamys hjsiosqiiillina is internal (Popham, 1939), as it is in P. yoyo and P. troglodytes (Mikkelsen and Bieler, 1989). Only the anterior and posterio-dorsal margins of Divariscintilla maoria are covered by the mantle (Judd, 1971). The number and placement of mantle tentacles and defensive appendages is strongly similar between P. lysiosquillina and those of P. yoyo and P. troglodytes (see Mikkelsen & Bieler, 1989; Popham, 1939). There are two primary anterior tentacles in P. lysiosquillina, P. yoyo and P. troglodytes as illustrated by Popham (1939) and by Mikkelsen and Bieler (1989), although P. troglodytes has a .second set of short anterior tentacles. Divariscintilla maoria has 6 to 8 large defensive ap- pendages (Mikkelsen & Bieler, 1989) or posterior ap- pendages (Popham, 1939), which are absent from P. lysiosquillina, P. yoyo and P. troglodytes. The ctenidia, usually an important source of ph\ logenetic information, are smooth in Divarisciiitilla maoria, but pleated in P. lysiosquillina (Popham, 1939) and in P. yoyo and P.
C. C. Conev. 1990
Page 143
troglodytes (Mikkelsen & Bieler, 1989). The unusual "flower-like" organ of Divariscintilla maoria and those discovered in P. ijoyo and P. troglodytes by Mikkelsen and Bieler (1989), were not reported by Popham (1939). Whether these "flower-like" organs were overlooked in P. lysiosquillina. or simply do not exist in this species, is unknown.
ACKNOWLEDGEMENTS
For loans of specimens of Divariscintilla maoria and Vasconiella jeffreysiana I thank Bruce A. Marshall (NMNZ) and Anders Waren (SMNH), respectively. I also appreciate the help of Silvard P. Kool, Museum of Com- parative Zoology, Harvard, and Lindsey T. Groves (LACM) in locating obscure literature. Pedro Baez, Luis Bracamontes, and Elizabet Ramos (LACM) kindK pro- vided translations of the foreign literature. John DeLeon, Dick Meier, and Don Meyer, LACM photography staff, made prints from SEM negatives. Special appreciation is expressed to Jack Worrall, Alicia Thompson, and Rob- ert F. Bils of the Center for Electron Microscopy and Microanalysis, University of Southern California, for helpful advice on the use of the Cambridge 360 scanning electron microscope. James H. McLean (LACM) kindly provided guidance and constructi\'e suggestions through- out the preparation of the manuscript. I also appreciate the very helpful reviews provided by Eugene V. Coan, LACM Research Associate, Robert S. Presant, Indiana I'niversity of Pennsylvania, LouElla Saul (LACM), and two anonvmous reviewers.
LITERATURE CITED
Aartsen, J. J. van. 197.5. Nogmaals Vasconiella jeffreysiana (P. Fischer) (uit Bretagne, Algeciras en Algerije), Corres- pondentie Blad Nederlandse Maiacologische N'ereniging 167;466-467.
.'\artsen, J. J. van. 1982. European marine Mollu.sea: notes on less well-known species IV. Vasconiella jeffreysiana (P Fischer, 1873). Basteria 4frl25-12H
Bernard, F. R 197.5. Rhamphidonia gen n from Xortii- eastern Pacific (Bivalvia, Leptonacea). Journal de Con- chyliologie 112:105-115.
Bernard, F. R. 1983. Catalogue of the li\ iiig BuaK ia of the Eastern Pacific Ocean: Bering Strait to C^ape Horn Ca- nadian Special Publication of Fisheries and .\quatic Sci- ences 61:1-102.
Berr\ , S. S. 19.59. Notices of New Eastern Pacific MolUisca — III. Leaflets in Malacology 1( IS): 107-1 14.
Bouchel, P., F. Danrigal, and C Hii\ ghens 1978. Coquillages des Cotes atlantiques et de la Manche Eilitons du Paci- fique, Paris, 144 p.
Bruggeman-Nannenga. M. \- 1975. .\ iKirtluTU extension of the known distribution of the bivalve Vasconiella jeffre- siana (P. Fischer, 1873) (Galeomatidae) [sic]. Basteria 39: 14.
Carter, J. G, and (;. R. C;lark. 1985. Classification and pli\- iogenetic significance of niolluscan shell microstructure. //!. Bottjer, b. J , C. S Hickman, and P D. Ward (eds.). Mollusks: notes for a short course. L niversit) of Tennessee, Studies in Geology 13, p. .50-71.
Cluivan, A, 1969. Supcrlaniib l.cplonaiea Gra\. IS47. In: Moore, R. C. (ed.). Treatise on invertebrate paleontolog\. Part N. Mollu.scaf). Bivalvia 2. (ieologicalSocietvoi Amer- ica (Boulder, Colorado) & I ni\crslly of Kansas (Law- rence), p. 518-537.
Cornet. M. 1982. Anatomical descrii)tion of \'asconi(7/a /c/- frcysiana (P. Fischer, 1873) (Mollirsca, Bivalvia, Leptona- cea! Journal of Mollu.scan Studies 48:36-43.
C<>\, L. R, 1969. General features of Bivalvia. In: Moore, R. C. (ed.) Treatise on iiuertebrate paleontology. Part \. Mollusca 6. Bivalvia 1 Geological Society of .America (Boulder, C^olorado) & L'niversitv of Kansas (Lawrence) p. 2-129.
Dall, W. H. 1899. Synopsis of the Recent and Tertiary Lep- tonacea of North .America and the West Indies. Proceed- ings of the I'nited States National Mu.seum 21:873-897, 2 pis.
Dekker, N. 1975. Nogmaals Vasconiella jeffreysiana (P. Fi- scher). Correspondentie Blad Nederlandse Maiacologische Verniging 167:466.
Fischer. P. 1873. In: de Foliii, L Exploration dc la losse de Cap-Breton en 1872. Les Fonds de la Mer 2 65-84
Fischer, P. 1874. Faune conchyliologique marine du departe- iiient de la Gironde et de cotes du Sud-Ouest de la France. Deuxieme supplement. Actes de la Societe Linneenne de Bordeaux 29:193-255.
Fischer. P. 1878. Essai sur la distribution geographi<iiie des Brachiopodes et des Mollusques du littoral oceanique de la France .Actes de la Societe Linneenne de Bordeaux 32: 171-215.
Fischer, P. 1887. Manuel de Conchy liologie et de Paleonto- logie conchyliologique. F Savy, Paris, 1369 p., 23 pis.
de Folin, L. and L. Perier 1878. Notice sur Les Fonds de la Mer. Memoires de la Societe des Sciences Physiques et Naturelles de Bordeaux 2:323-357.
Franc, A. 1960. Classe des Bivalves. /;j; Grasse, P P (ed. ). Traite de Zoologie 5:1845-21.33
Hertz, C. M. 1984. Illustration of the t\pes named by S. Stillman Berr\ in his "Leaflets in Malacology . The Fes- tivus 15, Supplement: 1-42
Hildalgo, J. G. 1917. Fauna maiacologica de Espana. Portugal \ las Baleares Moluscos testaceos marinos. Madrid, Tra- liajos del Museo National de Ciencias Naturales Serie Zoo- logica 30:1-752.
Judd. W. 1971. The structure and habits of Divariscintilla maoria Powell (Bi\alvia: Galeommatidae). Proceedings of the Malacological .Societ) of London .39:343-.)54
Keen, A. M. 1971. Sea Shells of Tropical West .America. (Second Ed) Stanford I'niversity Press, Stanford. (;.A xiv -I- 1064 p.
Kisch, B S 1958 Vasconiella jeffreysiana (P. Fischer). Pro- ceedings of the Malacological Societ\ of London ■33( 1 ):21- 24
Mienis, H, K 1975, Vasconiella jeffreysiana (P. Fischer) in de Golf van Biskaje. C;orrespondcnli(' Blad Nederlandse Maiacologische Wreniging 166:4.)1
Mienis, H.K. 1976. Vasconiella jeffreysiana (P. Fisclier) ook van Quiberon. Correspondentie Blad Nederlandse Mala- cologisclie Vereniging 169:522.
Mikkelsen, P M and R. Bieler 1989. Biology and compar- ative analonn of Divariscintilla yoyo .hkI D. tropfodytcs. two new species of (iaieommatidae (Bivalvia) from sto- niatopod burrows in eastern Florida Malacologia 31(1): 17.5-195.
Page 144
THE NAUTILUS, Vol. 104, No. 4
Montero Aguera. I. 1971. MoiiLstos l)ivaKi)sc.spaiiole.s, Publi- caciones de la Liiixcrsidad de Si'\illa .ol-'l'JS.
Morion, B. 197,5. D>iiiaiitic cli.splax in (Jalcomma polita Dc- slia\t'S (Bivalvia: Lcptonacea). Jcuirnal ol ( ^onchdlogy 28: 365-369.
Morton, B. 1976. Secondary brooding of temporary dwarf male.s in Ephippodonta [Ephippodontina) oedipus sp. nov. (Bivalvia: Leptonacea). journal of Conchology 29:31-39.
Nordsleck, F. 1969. Die europaisclien Meeresnuischeln (Bi- valvia). Voni Eismeer bi.s Kapverden, Mittelmeer und Schwarzes Meer, Stiittsiart
Olsson, A. A. 1961. Mollusks (it the tropical eastern Pacific, particularly from the .southern half of the Panamic-Pacific faunal province (Panama to Peru): Panamic-Pacific Pele- c\poda. Paleontological Research Institution. Ithaca, NY, 574 p., 86 pis.
Pasteur-Humbert, C. 1962. Les Mollusques inarins testaces du Maroc II Les Lamellibranches et les .Scaphopodes. Tra- vaux de I'lnstitut Scientifique Cherifien, Serie Zoologie 28: 1-184.
Ponder, W. F. 1971. Some New Zealand and Suhaiilarctic bivalves of the Cyamiacea and Leptonacea with descrip- tion of new taxa. Records of the Dominion Museum 7: 119-141
Popham, M. L. 1939 On Pldyciacnachlamys lysiosquillina gen. and sp. no\., a lamellihranch commensal in the bur- rows of I^ysiosqiiillii ruaciildta. British Museimi (Natural
History), Great Barrier Reef Ivxpedition 1928-29, Scien- tific Reports 6(2):61-84.
Powell. \. B. VV. 1932 On some New Zealand pelec> pods. Proceedings ot the Malacological Societx of London 20: 65-72, pi. 6.
Powell, A. B. W. 1962. Shells of New Zealand: an illustrated handbook, 4th ed. Whitcombe and Tombs Ltd., Christ- church, 203 p., .35 pis
Powell, A, B. \V, 1976 Shells of New Zealand: an illustrated handbook, 5th ed. Whitcoulls Publishers, Christchurch. 154 p.. 45 pis
Scarlato, O. A. and V I Starobogatov. 1979. General evo- lutionary patterns and the s\stem of the class Bivalvia, Proceedings of the Zoological Institute of the .-Kcadeni) of Sciences of the USSR 80:5-38.
Taylor, J. D., W. J. Kennedy, and A. Hall. 1973. The shell structure and mineralogy of the Bivalvia: II. Lucinacea — Clavagellacea conclusions. Bulletin of the British Museum (Natural History) 22(9):253-294, 15 pis.
X'erduin. .\. 1975, Vasconiella jejfrcysiana (P. Fi.scher) ook van ,\gadir, Correspondentie Blad Nederlandse Malacolo- gische V'ereniging 166:422,
Waren, A. 1980. Marine Mollusca described b\ John G\\\n Jeffreys, with the location of the type material. Concho- logical Society of Great Britain and Ireland, Special Pub- lication 1:1-60,
THE NAUTILUS 104 (4): 145-146, 1990
Page 145
Malacology or Conchology?
Robert Robertson
Department ot Malacology Acadeni) of Natural Sciences Nineteenth and the Parkway Philadelphia, P.\ 19103, USA
The choice of which of these two words to use depends not, as one might suppose, on etymology, priority, or the original intentions of the proposers, but on usage (and emotions!). The purposes of the present paper are to elaborate on these ideas, to record some apparently new insights on this old polemic, and to advocate use of mal- acology. This paper does not concern the pros and cons of studying living animals or shells.
The two competing terms for the stud\ of the ph\ lum Mollusca are malacology and conchology. To most mod- ern biologists, malacology means the study of molluscan animals (soft bodies plus shells if present) and conchology means the study of just their shells. The Greek word malakos and the Latin word molluscus apparently are not cognates, although they both mean soft. The Greek konche means either snail or shell (whence the English conch). In two editions of an excellent, scholarly book on the histor\ of shell collecting, S. Peter Dance (1966, 1986) has favored conchology for the study of whole mollusks. Dance quotes various authors to show that konche and its diminutive konchijlion could mean a shell- bearing mollusk, not only its shell. I give reasons here for favoring the term malacology, in answer to Dance (1966, 1986).
The polarity is deep-seated. In the United States there are the American Malacological Union and the Con- chologists of America. In the British Isles there are the Malacological Society of London and the Conchological Society of Great Britain and Ireland, etc.
The word conchyliologie, anglicized to conchology by da Costa (1776), was introduced in 1742 by the aristo- cratic cabinet naturalist Antoine Joseph Dezallier [or De- sallier] d'Argenville in the book L'Histoire Naturelle eclaircie dans deux de ses parties principales, la Lith- ologie et la Conchyliologie, dent I'une traite des Pierres et I'autre des Coquillages (Paris). The book primarily concerns minerals, fossils, and shells. D'Argenville de- fined concha and coquillage as an animal with a shell ("coquille ") plus its contained soft body or "fish" ("pois- son"). E.xpressly excluded from the book are most "mol- lusca, which to him meant soft-bodied animals without shells. Curiously, d'Argenville illustrated six terrestrial slugs. There are also, besides molluscan shells, illustra- tions of echinoids, barnacles, organ-pipe coral (Tubi-
pora), serpulid worms, etc. There were no illustrations of chitons, octopuses, squids, or cuttlebones.
The word malacologie. also French and anglicized in 1836 to malacology and apparently a contraction of mal- acozoologie, was one of two terms introduced in 1814, 72 years after d'Argenville, by the controversial and per- haps brilliant field naturalist Constantine Samuel Schmaltz Rafinesque. He meant by the term the study of "Mol- lusques" as he understood them ("Classe \ialacosia"). His second word, anopologie, was for a broader study. (One wonders how serious he was.) Rafinesque had no companion term for the shell bearers (or Conchifera). It is likeK that Rafinesque had more-or-less the same con- cept of "Mollusques " as Cuvier (1817), who included chitons and cephalopods in the group, but also ascidians, brachiopods and cirripedes. Characteristically, Rafin- esque proposed malacologie in a now-ver\ -rare booklet, this one verboseK entitled Principes Fondamentaux de Somiologie ou les Loix de la Nomenclature et de la Classification de I'Empire Organique ou des Animaux et des vegetaux contenant les Regies essentielles de I'Art de leur imposer des noms immuahles et de les classer methodiquemen t ( Palermo).
H. M. D de Blainville (1825), in the text of his Manuel de Malacologie et de Conchyliologie (Paris and Stras- bourg), did much to disseminate the word malacologie and to bring about use of the two terms in modern times. In two ways, de Blainville showed his preference for malacologie: his use of the two typefaces, and his stating that malacologie is a part of zoologv' while conchyliologie is an "art" (title page).
Both terms were proposed before the modern phylum Mollusca was conceptualized. But let us not have a new- term! (testaceology, the study of shells, and molluscologie are alreadv extinct).
D'Argenville was pre-Linnaean, but the binomial no- menclatural rule of prioritv is liardK t)perative. Original intentions and etymology seem more relevant, but un- fortunately do not pertain. The first s\ llables of mo/lusk and Mia/acology are convenientK- similar. Quite prop- erly, malacozoologv had been part of zoologx . .Also, soft- ness is common to the bodies of all mollusks, while shells are not. Rafinesque came closer to the modern concept of the Mollusca than d'Argenville. who (as shown above)
Page 146
THE NAUTILUS, Vol. 104 , No. 4
Figure 1. Constantine Samuel Schmaltz Rafinesque (1783- 1840), who proposed the term malacologie in 1814. The au- thenticity of this portrait has been questioned (LaRocque, 1964).
Figure 2. Antoine Joseph Dezallier d'Argenville (1680-1765), who proposed the term conchyliologie in 1742. From the en- graving in Favanne and Favanne (1780).
grouped in it a variety of shelly animals. In a later pub- lication, Rafinesque did include cephalopods in his Mol- lusques. It is admitted that these are slender arguments for malacology. But is the case for conchologij any better? Even though to an ancient Greek malacologia might have meant a discourse on anything soft, to me, a biologist, the term malacology is preferable to conchology for the modern branch of zoology concerning mollusks. How- ever, the dual usage no doubt will continue.
I thank Professor A. J. Cain (via Dr. A. E. Bogan) for bringing to my attention Rafinesque's apology.
LITERATURE CITED
Costa, E. M, da. 1776. Elements of conchology: or, an intro- duction to the knowledge of shells. London, p i-viii -I- 1- 318, 7 pis.
Cuvier, [G. L. C. F. D.]. 1817. Memoires pour servir a I'His- toire et a I'Anatomie des Mollusques. Paris. Pagination comple.x, ca. 38 pis. Most originally in .Annales du Museum d'Histoire Naturelle [Paris], beginning 1802.
Dance, S. P. 1966. Shell collecting; an illustrated history. Faber & Faber, London or University of California, Berke- ley, p. 1-344, 35 pis.
Dance, S. P. 1986. A history of shell collecting. Revised ed. of above. E. J. Brill/Dr. W. Backhuys, Leiden, p. i-xv + 1-265, col, frontispiece + 32 pis
Favanne, J. de and J. G de Favanne 1780. La Conchylio- logie, ou Histoire Naturelle des Coquilles. . . . [ed, 3 of d'Argenville's Conch\ liologie], Paris, 3 vols,
LaRocque, A. 1964. .\ Rafinesque portrait. Sterkiana 16:1-2, Ipl
INSTRUCTIONS TO AUTHORS
THE NAUTILUS publishes papers on all aspects of the biology and systematics of mollusks. Manuscripts de- scribing original, unpublished research as well as review articles will be considered. Brief articles, not exceeding 1000 words, will be published as notes and do not re- quire an abstract. Notices of meetings and other items of interest to malacologists will appear in a news and notices section.
Manuscripts: Each original manuscript and accompa- nying illustrations should be submitted in triplicate. Text must be typed on one side of S'^ x 11 inch white paper, double spaced throughout (including literature cited, ta- bles and figure captions), with at least 1 inch of margin on all sides. All pages must be numbered consecutively. If printed on a word processor, the right margin should be ragged rather than justified. Authors should follow the recommendations of the Council of Biology Editors Style Manual, which is available from the Council of Biology Editors, Inc., 9650 Rockville Pike, Bethesda, MD 20814, U.S.A. The first mention of a scientific name in the text .should be accompanied by the taxonomic au- thority, including year. Latin names and words to be printed in italics must be underlined; leave other indi- cations to the editor. Metric and Celsius units are to be used.
The sequence of sections should be: title page, abstract page, introduction, materials and methods, results, dis- cussion, acknowledgements, literature cited, tables, fig- ure captions, figures. The title page should include the title, author's name(s) and address(es). The abstract page should contain the title and abstract, which should sum- marize in 250 words or less the scope, main results and conclusions of the paper. The abstract may be followed by a maximum of 8 key words. All references cited in the text must appear in the literature cited section and vice versa. In the literature cited section, all authors must be fully identified and listed alphabeticallv. Follow a recent issue of THE NAUTILUS for bibliographic style, noting that journal titles must be unabbreviated. Infor- mation on plates and figures should be cited only if not included in the pagination. Tables must be numbered and each placed on a separate sheet. A brief legend must accompany each table. Captions for each group of illus- trations should be typed on a separate sheet and include a key to all lettered labeling appearing in that group of illustrations.
All line drawings must be in black, high quality ink, clearly detailed and completely labeled. Photographs must be on glossy, high contrast paper. All figures are to be consecutively numbered (figs. 1, 2, 3, ... , NOT figs. la. lb, Ic, . . . NOR plate 1, fig. 1 . . .). Illustrations must be arranged in proportions that will conform with the width of a page (6% inches or 171 mm) or a column (SVi inches or 82 mm). The maximum size of a printed figure is 6¥4 by 9 inches or 171 by 228 mm. A\\ illus- trations must be fully cropped, mounted on a firm, white backing, numbered, labeled and camera ready. The au- thor's name, paper title and figure number(s) should ap- pear on the back. Original illustrations must be between one and two times the desired final size. It is the author's responsibility that the line weight and lettering are ap- propriate for the desired reduction. Original illustrations will be returned to the author if requested. Color illus- trations can be included at extra cost to the author.
Voucher Material: Deposition of type material in a recognized public museum is a requirement for publi- cation of papers in which new species are described. Deposition of representative voucher specimens in such institutions is strongly encouraged for all other types of research papers.
Processing of Manuscripts: Upon receipt, every manu- script is acknowledged and sent for critical review by at least two referees. These reviews serve as the basis for acceptance or rejection. Accepted manuscripts are re- turned to the author for consideration of the reviewers' comments. A finalized version of the manuscript is re- turned to the editor and sent to press. Two sets of proofs are sent to the author for correction. Changes other than typesetting errors will be charged to the author at cost. One set of corrected proofs should be sent to the editor as soon as possible. Authors with institutional, grant or other research support will be billed for page charges at the rate of $60.00 per printed page.
An order form for reprints will accompany the proofs. Reprints may be ordered through the editor.
Manuscripts, corrected proofs and correspondence re- garding editorial matters should be sent to: Dr. M.G. Harasewych, Editor, Division of Mollusks, NHB stop 118, National Museum of Natural History, Smithsonian In- stitution, Washington, DC 20560, USA.
THIS PUBLICATION IS PRINTED ON ACID-FREE PAPER.
^ i i^ ^ ^Kf « % t f •■# * ^ & * i . *• * ^ -*^
# # ■'I ^ ■ ^at » . ."^ ^' '. -
III
^%%^^^.
x.-^
**«*«*-•
'..''•i
^^:.f.
i'
r.$:> <
«_.«
'f ~f .«
•%.^i *
*:*<i^.
' .■.V, !• '
^•a^
-(.■->.■
fe
»'1¥"#lv\%^^'*
.^.'l
•■(■: ■;--,s-. ,r'
iA'/vr-v^'
^'■■m
afti
t;i Ci; +■
yw'
''■i/^h'-^.^
•7 '-J''"''!'
>i \-A:^
rT^'
4 4_
*^*..t >_# i fl^
V€*f**%\*
.^%v%
t f
f f I t I t J;-
■■'^..4..
*-^-*^«A^
IL*
Jaf^-
> i
%*^9LlkM.il^..
,.,S ,-..., |«&.,S: f^'# A|P - f f f I I r* *: # /^' I f « If/
,J»L^
iniv. f. fTif t^
ii>-..i;
'tVfVt'
/.^ms
royoouo
# *
mikm mm
w^i^W'L.-^I^L. ^1^.''^,'
9= r -§■ ^-
f
f I I
f I I
f i
i I
f I
»Lk:
p f'' i* IS
»^ins
?'•' • ■
f fi I
IT I i
.'^V,^^^^^^^
r^'^-,*t^^^^a:*t^^*1
m.m..^..
^..;#,
*■ 1?f* »S"'
m r
t
I II I
I.
J I i
I
i 1
I • I
I I f
i
« 1
^#.K
,*L*Lf'
I
,.r* *"«•*'!?
ViVAVit***'
^Aj.*^*.
^ i-^ i^' ^ m i^ ^
^'^^^■^^^^^•?i6M*SM^^
i:ciVi
f
1 1 I
I T ff l|| i
( t I
I
itfLfLO
«:'*■
.^V
j[*t!«
i
I
I I
iijj^- . . »V
«W»--|l'«-*-«-*'«-«-»'.»->--r-ft--*-m-.-»r,rr»
t I
1 ii
'^^'^
c^«._*-
rn^ir
^VVmi^*^^^
^ji.!ty#
m '^
#^.
-t^-^^^r
xo
» ?*
^v^#*#^
^^4^*,..t..:€-
^"ur
'mn^
i :i f '
i:i::i f f f ■
^«w«^-«_.-ii
^i^«y«i,%%%%^%^^
■^%%%
^^ai 3K^« tf^iBi^
'af'"*-^:;-
1^%%
l.'«Jt'i't
■fit
.W^^«*¥*
'-'f'^ir
'?.«'»■..
■t.i
^^%
:*._t-*^»^'*''
Y,'^^y^^^^^r^.
i^^^V^
,^i^
^#^*
'f-'t^t
* « ./t ,.»
' ' i M a «
:--«.«:*"»'»
t*#
* »!:'«■