OBSERVATIONS ON PELAGIC BIRDS IN THE SOUTH ATLANTIC OCEAN IN THE AUSTRAL SPRING
Maurice A. E. Rumboll and Joseph R. Jehl, Jr.
TRANSACTIONS
OF THE SAN DIEGO sone e | Y OF NATURAL HISTORY
VOL. 19, NO. 1 29 SEPTEMBER 1977
OBSERVATIONS ON PELAGIC BIRDS IN THE SOUTH ATLANTIC OCEAN IN THE AUSTRAL SPRING
Maurice A. E. Rumboll and Joseph R. Jehl, Jr.
TRANSACTIONS
OE THE SAN DIEGO some E).yY OF NATURAL HISTORY
VOL. 19, NO. 1 29 SEPTEMBER 1977
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
VOLUME 19 1977-1982
CONTENTS
_ Observations on pelagic birds in the South Atlantic Ocean in the austral
spring. By Maurice A. E. Rumboll and Joseph R. Jehl, Jr. 29 September 1s ase Re REA Sieve serek ettatie alla or a tak tay at oxtail nobis Soh sMayn omapeher oy oNger
_ The Nannoniscidae (Isopoda, Asellota): Hebefustis n. gen. and Nannonis-
coides Hansen. By Joseph F. Siebenaller and Robert R. Hessler. 14 October HG HeRr te sete ae eee iss etek oe he Sas ete tae we ore era) Suse ones aiare) al ogee Rea Curt okeacn
_ First records of Risso’s dolphin (Grampus griseus) from the Gulf of
California with detailed notes on a mass stranding. By Stephen Leatherwood, Carl L. Hubbs, and Matilda Fisher. 25 June 1979 ..............+..+48-
_ Joanellia lundi sp. nov. (Crustacea: Malacostraca) from the Mississippian
Heath Shale of central Montana. By Joan M. Schram and Frederick R. Salieri Ooeinls OTS) pee eae on tote ae oo bcm o oot OOo
_ The genus Archaeocaris, and a general review of the Palaeostomatopoda
(Hoplocarida: Malacostraca). By Frederick R. Schram. 25 June ONS aeons
_ Limulines of the Mississippian Bear Gulch Limestone of central Montana,
USA. By Frederick R. Schram. 19 September 1979 ..........+-eeeeeeee
. A new species of chiton (Mollusca: Polyplacophora) from the Hawaiian
Islands and Tahiti. By Antonio J. Ferreira and Hans Bertsch. 19 September MOG OR rege pe ecco arene ce ay or ee “eactn ale sret este ya PRR) soegc nel Sr sgehor Fossil carrion beetles of Pleistocene California asphalt deposits, with a synopsis of Holocene California Silphidae (Insecta: Coleoptera: Silphidae). By Scott E. Miller and Stewart B. Peck: 12 October 1979 .........-..-.
_ Worms of the Mississippian Bear Gulch Limestone of central Montana,
USA. By Frederick R. Schram. 8 November 1979 ........---eeeeeeeees
_ A revision of the subfamily Syneurycopinae (Isopoda: Asellota: Eurycopidae)
with a new genus and species (Bellibos buzwilsoni). By Julie Ann Haugsness Ando bento. elessicr a2 Mecemben 19795. ce ce ce ee oes iio
_ A new scalpellid (Cirripedia),; a Mesozoic relic living near an abyssal
hydrothermal spring. By William A. Newman. 12 December OF ON oe ee
. Four species of Prerynotus and Favartia (Mollusca: Gastropoda: Muricidae)
from the Philippine Islands. By Anthony D’Attilio and Hans Bertsch. 10 /Noytill WIND s occ 66 600 aco. to oo FU Ura on On 0b OO OOM ICO ino A ay
_ A revision of the species of Cafius Curtis from the west coast of North
America with notes of the east coast species (Coleoptera: Staphylinidae). By R. E. Orth and Ian Moore. 30 June 1980..........- see eee e eee eee
. Dithyrocaris sp. (Phyllocarida) from the Allegheny Group of Ohio. By
Joan Matthews Schram. 14 November 1980 .............cccecsesseees
_ A late Pleistocene molluscan fauna from San Dieguito Valley, San Diego
County, California. By Thomas A. Deméré. 14 November 1980 .........
. The genera of the Nannoniscidae (Isopoda, Asellota). By Joseph EF.
Siebenaller and Robert R. Hessler. 7 July 1981........... eee eee ee eens
. The higher taxonomy and evolution of Decapoda (Crustacea). By Martin
DaBurkenroad. 7 July 198i... CAINE AS GER) POT OO OC ied Ree
. Biomere boundaries in the Phanerozoic time scale. By Frederick A. Sundberg
and Richard He Muller. 22 January 1982 22.22. ccm e cress = meine se
. The origin of Darwin’s finches (Fringillidae, Passeriformes). By David W.
Steadman: GO Aeust 1982.2 nce joc. icc 6 ce weiss a mis see ue cies nels wie ners
1-16
17-44
45-52
53-56 57-66
67-74
75-84
85-106
107-120
121-151
153-168
169-180
181-212 213-216 217-226 227-250 251-268 269-278
279-296
i
_ _
, * " . : . =m >
Observations on pelagic birds in the South Atlantic Ocean in the Austral Spring
Maurice A. E. Rumboll and Joseph R. Jehl, Jr.
ABSTRACT.—We studied seabird distribution beyond the continental shelf off eastern South America, between Tierra del Fuego (53°S) and southern Brazil (29°S) in the austral spring of 1975. Bird populations seemed low in this little studied area, but data from other seasons are too few to permit comparisons. Maximum numbers and diversity ocurred in the immediate vicinity of the Subtropical Convergence. The distribution of several species was largely restricted to zones of surface water (Subantarctic, Subtropical) on each side of the convergence. The occurrence of three immature Emperor Penguins (Aptenodytes forsteri) at 40°30’'S, 54°34’W establishes the northernmost record for this Antarctic species.
Basic information on seabird distribution in the South Atlantic is surprisingly scanty. Most recent studies (e.g., Tickell and Woods, 1972; Cooke and Mills, 1972; Jehl, 1974; see also Watson et al., 1971 and references therein) have dealt largely with populations over the continental shelf or along the continental slope. This is not surprising as pelagic bird studies must usually be carried out incidental to other oceanographic or commercial activities. As a result, our knowledge is strongly biased in favor of those species that frequent near-shore waters or commercial shipping lanes.
An opportunity to obtain ornithological data from the little-studied area beyond the continental shelf of eastern South America was realized in the austral spring of 1975, when the R/V Hero was assigned to support studies on marine verte- brates in the South Atlantic (Cruise 75- a This paper reports on the ornithological results of that cruise.
ITINERARY AND METHODS
Hero departed Ushuaia, Argentina, on 10 September, passing eastward through the Beagle Channel, and then northeastward through the Strait of Le Maire along a course parallel to but slightly beyond the edge of the continental shelf. On the morning of 16 September, Hero left the cold Subantarctic Zone of surface waters, passed through the Subtropical Convergence, and entered the warmer, less productive waters of the Subtropical Zone. At noon on 20 September Hero reached its northernmost station (28° 44’S) off southern Brazil and headed ESE to the Bromley Plateau (31° 30’S, 33° 30’W), arriving on 23 September. The route then turned southward and southwestward, and between 24-28 September generally fol- lowed or paralleled the edge of the Subtropical Convergence. On 29 September, Hero reentered subantarctic waters and continued southwestward, passing the Falkland Islands on 3 October and arriving in Ushuaia on 6 October (Fig. 1).
Shipboard observations and censuses were made by Rumboll with the assistance of R. L. Brownell, Jr. and other members of the scientific party and ship’s crew. Censuses were made for a ten minute period during each two hour interval through- out the day. All birds seen were counted and the number of ship-following species was estimated (Table 1). Other observations and counts were made as often as possible, as work schedule and weather permitted. Censuses were not taken when the ship was stopped for studies of marine mammals. Surface water temperatures were taken at 0800, 1200 and 1800 hours. Distribution and densities of the commoner species are shown in Figures 2 - 11.
SAN DIEGO SOC. NAT. HIST., TRANS. 19(1):1-16, 29 SEPTEMBER 1977
Figure 1. Cruise route of the R/V Hero (Cruise 75-5) in the South Atlantic Ocean, 11 September to 4 October 1975. Numbers indicate ship’s noon position on each date from 11 September to 4 October. Heavy dark line marks the approximate location of the Subtropical Convergence. The light line marks the boundary of the continental shelf.
Weather conditions varied considerably but were, in general, suboptimal. Rough seas prevailed on many days, which seriously hampered observations, pre- cluded collecting, and made sightings of birds flying close to or sitting on the water nearly impossible. A dense fog on 29 September virtually eliminated observations.
Collecting was done as opportunity presented. Specimens are deposited in the Natural History Museum, San Diego. Plankton samples were obtained daily; they have been deposited in the Museo Argentino de Ciencias Naturales ‘‘Bernardino Rivadavia,’ Buenos Aires. Mallophaga were deposited at the University of Canterbury, Christchurch, New Zealand.
This study was supported by a grant from the National Science Foundation (NSF - OPP75 - 19724). The assistance of George E. Watson in identifying critical specimens is gratefully acknowledged.
ANNOTATED LIST OF SPECIES
Emperor Penguin (Aptenodytes forsteri).—The sighting of this species constitutes the most remarkable distributional record of the cruise. On 15 September, Rumboll saw two birds 100 m ahead of the Hero and watched them carefully until they dove when the ship was only 20 m distant; one hour later he saw a single bird. He noted that the color of the ear patch was washed out, which indicates that the birds were juveniles. Rumboll has had extensive experience with King Penguins (A. patagonica) on the Falkland Islands and is confident of his identification. The sightings were made at 40° 30'S, 54° 34’W, some 40 miles S of the Subtropical Convergence and over 400 miles off southern Buenos Aires Province, Argentina. This is by far the most northern record for either species of Aptenodytes (cf. Watson et al., 1971). The sighting of three birds in this ornithologically unexplored area—and hundreds of miles north of the pack ice—suggests that the winter range of juvenile or non- breeding Emperors may be far more extensive than is currently realized.
Gentoo Penguin (Pygoscelis papua).—One, 30 mi. SE Falkland Islands, 3 November.
Rockhopper Penguin (Eudyptes crestatus).—Small penguins, almost certainly of this species, were encountered, very uncommonly, in cold waters from west of the Falklands north to the latitude of the Valdes Peninsula (12-15 September), and on several days between 30 September and 5 October, as the ship approached and passed by the eastern edge of the Falklands. The largest flock was 7; most flocks comprised two or three individuals. This species probably winters fairly commonly in deep water beyond the continental shelf as far north as Uruguay (Jehl, 1974).
Magellanic Penguin (Spheniscus magellanicus).—This species is common over the continental shelf but rare over deeper waters (Jehl, 1974). The only sightings during this cruise were groups of 4 and 5 in the Beagle Channel on 10 September, 3 birds north of the Falklands on 13 September, and groups of 2, 2, and 3 far east of the Valdes Peninsula on 15 September. .
Wandering Albatross (Diomedea exulans).—Widely distributed, though mostly uncommon, over entire route, with maximum numbers (18 on 25 September) in the vicinity of the Subtropical Convergence. No first-year birds were observed. Rumboll noted that most of the birds north of 35°S trailed their feet, whereas those farther south folded them forward into their belly feathers. This behavior may be related to thermoregulation and requires further substantiation. Rumboll did not identify any examples of D. epomophora, which seems to prefer shallower shelf waters (Jehl, 1974; Watson et al., 1971).
Black-browed Albatross (Diomedea melanophris).—Seen along the entire cruise route, though very uncommon in warm waters north of and remote from the Sub- tropical Convergence. The largest numbers (100-400 individuals) were encountered in the vicinity of the Falkland Islands, where the species nests. Rumboll noted the virtual absence of immatures, no more than 10 being recorded on the entire cruise. A concentration of 300 on 3 October near the Falklands was associated with a herd of Pilot Whales (Globicephala melaena) and Dusky Dolphins (Lagenorhynchus australis).
Yellow-nosed Albatross (Diomedea chlororhynchos), Gray-headed Albatross (D. chrysostoma).—On 23-25, and 27 September RKumboll saw small numbers of immature Yellow-nosed Albatrosses in warm waters north of the Subtropical Convergence. Gray-headed Albatrosses were recorded definitely on 26 September (1 bird) in the vicinity of the Convergence and were seen regularly but uncommonly thereafter to the vicinity of Staten Island (maximum 7 on 30 September). Fifteen ‘‘gray-headed”’ albatrosses were seen under poor conditions on 24 September. Rumboll felt that more than one species was present, but in view of the relatively high water temperatures (15.5°C) it seems likely that most were chlororhynchos.
Figure 2. Distribution of Diomedea melanophris (outside of cruise track), and Diomedea exulans (inside of cruise track). Key to densities pertains to Figures 2-11.
The predilection of chrysostoma for colder waters is well known. An adult chrysostoma weighed 3700 g.
Sooty Albatrosses (Phoebetria fusca, P. palpebrata).— Both of these species were observed, fusca much more commonly (21 vs. 6 sightings). Records of palpebrata were made along or south of the Subtropical Convergence, whereas fusca preferred warmer waters.
Giant Petrel (Macronectes giganteus).—Giant Petrels (all presumably M. giganteus) were common in Subantarctic waters, uncommon along the Subtropical Convergence, and almost unrecorded in the Subtropical zone. With the exception of a white-phased bird near Staten Island on 4 October, all sightings were of dark- plumaged individuals.
Southern Fulmar (Fulmarus glacialoides).— Regular and fairly common south of the Subtropical Convergence, but most abundant in the vicinity of land (Tierra del Fuego, Falklands). Only two individuals were sighted north of the Convergence.
Cape Pigeon (Vaption capensis).—This was the species encountered most commonly. It occurred throughout the entire cruise area, though it was much less common north of the Subtropical Convergence. Cape Pigeons are well known scavengers and immediately investigate floating scientific specimens or garbage. Rumboll saw several using their wings to dive after jellyfish. On 17 September, he saw two birds with bright pink patches on the belly, perhaps marked by other researchers.
fe]
eee 25°
Figure 3. Distribution of Diomedea chrysostoma (outside) and Diomedea chlororhynchos (inside).
Prions (Pachyptila spp.).—Packs of prions were fairly common over the southern half of the cruise route, except in the vicinity of land, and were particularly common along the Subtropical Convergence. One possible P. belcheri was identified among many prions seen on 16 September. On 27 September, along the Subtropical Convergence, Rumboll collected 3 prions and on 30 September, south of the Con- vergence, 4 more. Although these show considerable variation in bill shape, all seem referable to salvini, and are presumed to have originated on Tristan da Cunha (G. E. Watson, pers. comm.). These records considerably extend the western range of salvini (cf. Watson et al., 1971).
Blue Petrel (Halobaena caerulea).—A single bird NE of the Falklands on 2 October, and three birds probably of this species on 16-17 September. The latter records, if correct, seem far north for this predominantly cold-water species.
Atlantic Petrel (Pterodroma incerta).—This was the commonest and most easily identified species of Pterodroma. Although it was regular along the northern part of the route, it was most abundant in the immediate vicinity of the Subtropical Convergence. A male weighed 650 g.
Soft-plumaged Petrel (Pterodroma mollis).—Encountered daily between 17 and 26 September, in Subtropical waters. Only a few were seen each day; the highest count, 21, was made on 20 September.
Pterodroma spp.—Between 21 and 25 September, north of the Convergence, Rumboll observed a few individuals of two or more species of Pterodroma. His descriptions suggest Pt. arminjoniana (mainly) and Pt. lessoni (one record).
Figure 4. Distribution of Phoebetria palpebrata (outside) and Phoebetria fusca (inside).
Shoemaker (Procellaria aequinoctialis).—This species, which prefers deep, offshore waters (Jehl, 1973, 1974) was sighted throughout the entire cruise, but was rare in the Subtropical zone. No significant concentrations were observed. Two individuals of P. a. conspicillata were seen along the Convergence on 24-25 September. A specimen of P. a. aequinoctialis weighed 1100 g.
Pediunker (Procellaria cinerea).—The Pediunker, or Gray Petrel, was widely distributed over deep waters, most records being made near the Subtropical Convergence. On most days no more than one bird was reported. The largest con- centration, 13 in an afternoon, was found in the vicinity of a herd of Pilot Whales well off Golfo San Jorge on 14 September. A male collected on 28 September weighed 1050 g. Distribution maps in Watson et al., (1971) suggest that the Pediunker and Shoemaker are commoner over the Continental Shelf than farther offshore. This is an artifact, resulting from the fact that most seabird observations in the South Atlantic have been made near the coast. Actually, both species prefer deep waters, and the Pediunker is extremely rare over the shelf (Jehl, 1974, Cooke and Mills, 1972).
Cory’s Shearwater (Calonectris diomedea).—An unidentified shearwater at the Bromley Plateau on 23 September was probably this species, which has recently been reported wintering in fair numbers off the coast of northern Argentina (Cooke and Mills, 1972).
Figure 5. Distribution of Fulmarus glacialoides (outside) and Macronectes giganteus (inside).
Sooty Shearwater (Puffinus griseus).—Seen along most of the cruise route, but common only in cool waters; very rare or absent in warm waters. Areas of local abundance, principally near Staten Island and in the Strait of Le Maire, are near presumed nesting localities. A flock of 3000 along the south shore of Staten Island in the early evening of 4 October may have been flying toward a staging area.
Greater Shearwater (Puffinus gravis).—Watson (1975) considers this a species of ‘cool waters near the Subtropical Convergence.’’ During this cruise it was found almost exclusively in warm waters north of the Convergence, where it was fairly common. Its distribution paralleled that of Pterodroma mollis and _ largely complemented that of Puffinus griseus, which occurred mainly in cooler waters.
Manx Shearwater (Puffinus puffinus).—Three individuals near 37° 30’S, 34°W were the only sighting of this species, which winters commonly off the South American coast between Brazil and northern Argentina.
Small shearwaters (Puffinus spp.).—On 26 September, near 39°S, 35°S 33’W, Rumboll saw a single small shearwater with an extremely fast and shallow wing beat, a brownish back, and with the white of the undertail coverts extending upward onto the sides of the rump. These characters suggest the Fluttering Shearwater (P. gavia), which is only known to occur in the New Zealand region. On 20 September he saw another small shearwater, but with a pale grayish back. This observation may refer to the Allied Shearwater (P. assimilis), which has been reported from the general area.
Figure 6. Distribution of Daption capensis (outside) and Pachyptila sp. (inside).
Wilson’s Storm-Petrel (Oceanites oceanicus),—Uncommon though scattered along the entire route; seemingly commonest near the Subtropical Convergence and rarest in waters warmer than 17°C. Rumboll noted that it was most frequently seen near patches of floating kelp. A specimen taken 46° 24’S, 56° 55’W is referable to O. oO. oceanicus.
Gray-backed Storm-Petrel (Garrodia nereis).—Rare, a total of 11 birds seen on 6 dates. All observations were made south of the Subtropical Convergence and beyond the continental shelf.
Black-bellied Storm-Fetrel (Fregetta grallaria).—Rare, a total of 13 birds observed on 10 dates. Except for a tendency to remain far offshore, the species exhibited no obvious distributional pattern, occurring in very cold as well as in very warm waters. Many observations were made north of the range shown by Watson et al., (1971).
Diving-Petrels (Pelecanoides spp.).—Diving petrels were fairly common in the vicinity of the Beagle Channel and Strait of Le Maire (10-11 September, maximum 150) and in the vicinity of the Falklands and Staten Island (3-5 October). Two speci- mens of P. urinatrix were taken aboard ship on 4, 5, October; presumably all records pertain to that species. Several diving-petrels were seen beyond the continental shelf off Buenos Aires Province on 26-27 September (maximum, 14 on the 27th); from previous records (Jehl, 1974) it seems probable that these were urinatrix.
Figure 7. Distribution of Pterodroma mollis (outside) and Pterodroma incerta (inside).
Skuas (Catharacta spp.).—Skuas were seen occasionally, though rarely more than one per day, with most records from north of 47°S. The birds rarely approached the ship and Rumboll made no attempt to determine which form(s) was present.
Jaegers (Stercorarius spp.).—Three unidentified jaegers were seen off the coast of Brazil on 19-20 September. -
Kelp Gull (Larus dominicanus).—Uncommon but regular south of 48°S. All observations were made within 300 miles of land.
Terns (Sterna spp.).—Scattered terns, usually individuals but occasionally small flocks, were seen between 48°S and 29°S. There was no obvious pattern; maximum concentrations (14, 9 birds) were observed near the Subtropical Convergence on 16 and 29 September, respectively. Terns rarely approached the ship and specific identification was impossible, although most observations presumably refer to S. hirundinacea.
10
Figure 9. Distribution of Puffinus gravis (outside) and Puffinus griseus (inside).
Figure 11. Distribution of Oceanites oceanicus (outside) and Aptenodytes forsteri (inside).
11
12
TABLE 1. Summary of daily censuses. Abundance indicated is average number of birds per ten minute census
are omitted. = ee September 1]
: _ 11 12 13 14 15 16 17 18 19 20 21 Eudyptes sp + + + 0.2 \ Diomedea exulans 0.7 0.3 + + 0.6 0.7 0.2 0.3 Diomedea melanophris 1.0 15.5 5:3 4.2 0.5 0.6 0.7 0.2 0.2 Diomedea chlororhynchos Diomedea chrysostoma Phoebetria fusca + + Phoebetria palpebrata + Macronectes giganteus 4.0 4.0 3.8 43 1.3 0.2 Fulmarus glacialoides Dre 0.2 0.5 + 0.8 0.2 Daption capensis 3.5 9.2 11.0 15.7 2.8 8.4 Syi/ 2.8 2.6 0.2 0.4 Pachyptila sp. 0.5 + 1.0 + + 74 Procellaria aequinoctialis 0.2 + + 0.3 0.2 0.2 Procellaria cinerea 1.8 + Puffinus gravis 0.4 0.3 0.2 0.2 0.4 3.0 Puffinus griseus 10.5 1.5 0.2 0.2 + + 0.3 0.2 Pterodroma incerta 0.5 0.3 4.4 2.0 0.2 0.2 Pterodroma mollis 0.2 1.0 1.0 0.6 0.6 Pterodroma sp. 0.2 Oceanites oceanicus 0.2 0.7 0.7 0.6 0.8 0.3 + 0.2 Fregetta tropica + + Garrodia nereis 0.2 + 0.7 Storm-petrel sp. 12 0.8 0.3 Pelecanoides sp. 3.0 Catharacta skua 0.2 a fe + + Larus dominicanus + + 0.2 Sterna sp + 0.2 + 0.8 Periods of observation 4 6 6 6 6 5 6 5 6 5 5 Latitude °S 53°50'S 51°17'S 48°05'S 44°45'S 41°50'S 38°53’S 36°32'S 33°22'S 31°14'S 28°44'S 28°45'S Longitude °W 64°10'W 62°19'W 59°42'W. 57°11'W54°50'W 52°52'W 50°23'W 47°41'W 45°51'W 44°05'W 41°02'W Sea temperature °C 8.9 6.4 6.6 7.5 7.8 16.7 16.1 18.3 17.7 20.0 20.5
No. species ie) 11 11 13 17 13 12 9 8 9 8
13
period. Birds seen during the day, but not in census period, are indicated by +. Species seen on fewer than four dates
October 22 23 24 25 26 27 28 29 30 1 2 3 | 4 5 + + + 0.8 0.2 0.1 3.0 0.4 1.5 Se Ue 0.2 0.7 0.5 0.5 0.2 0.2 0.2 3.0 2.0 2.0 1.0 0.2 3.3 0.8 EZ 13.5 35 0.4 + 0.8 1.0 0.2 ? + 0.2 0.4 0.2 1.0 0.2 0.3 - mn + 0.6 0.6 0.2 0.2 + + 0.2 + 1.6 2.0 0.2 7 0.3 1.8 5.0 1.2 3.5 1.0 + lat 0.8 0.8 3.2 0.3 0.8 + 1.0 1.6 17.4 30.4 4.5 3.2 + 8.7 0.8 Us) 11.0 10.8 44 + 11.4 40.8 37.5 0.6 1.0 14.0 10.8 0.3 8.3 0.2 + 1.0 1.2 12 0.2 0.2 0.3 + + + + 0.2 1.2 2.0 1.4 + 0.6 + + + + + 0.2 0.2 + 0.2 83.8 ~ + + + 0.2 0.8 3:2 0.5 1.8 + 0.2 2.0 + 0.2 0.4 + 0.4 + 1.0 1.0 + + 1.0 + + oF + + + 0.2 0.5 ~ 0.5 0.2 + 0.4 0.2 + 7 + ote 3 0.2 ats we 0.3 + + + + “ oP at 5 5 5 5 5 4 5 4 6 4 6 6 6 5 eet 42'S 35°04'S 37°32'S 39°18'S — 43°58'S 45°44'°S 47°29'S 48°42'S 50°11'S 52°20'S 54°12'S 50°00'S 37°19'W 33°47'W 32°20'W -33°55’W 35°54'W — 41°31'W 45°49'W 50°10'W 52°28'W 53°32'W 58°06'W 62°32'W 64°55" W 20.0 174 15.5 14.4 11.5 = 8.5 9.0 5.8 5.0 3.9 5.0 55 6.5
8 13 15 17 17 16 13 10 17 10 13 1 14 9
DISCUSSION
The sparseness of seabirds over the open ocean was impressive. In the Subant- arctic Zone birds were uncommon and diversity was moderate, 12-13 species being recorded on most days. In the Subtropical Zone birds were rare, only 8-9 species being seen each day. The greatest numbers and diversity (16-17 species daily) occurred near the Subtropical Convergence, where warm- and cold-water faunas intermingled. But even there numbers were low. Lacking quantitative data from other years or other seasons, we are unable to advance any firm interpretation for these data. (Data obtained by Tickell and Woods [1972, Table 5] during a cruise between the Equator and South Georgia are not strictly comparable.)
The low numbers of Southern Hemisphere residents encountered may be a seasonal phenomenon, adults having already retreated southward to the vicinity of nesting islands. The low numbers of trans-equatorial migrants (Sooty and Greater shearwater, Wilson’s Petrels) may indicate that birds summering in the Northern Hemisphere had not yet returned. Similarly, we are unable to compare deep water vs. continental shelf avifaunas, as the only available quantitative data from the shelf pertain to winter (Jehl, 1974) or mid-summer (Cooke and Mills, 1972) transects, except to point out the absence or rarity of species that prefer nearshore waters (Magellanic Penguin, Royal Albatross, Sooty Shearwater, Magellanic Diving-Petrel).
Very few concentrations were encountered. Local pockets of diving-petrels and Sooty Shearwaters in the Strait of Le Maire on 11 September and larger flocks of sooties at Staten Island on 4 October seem attributable to the proximity of nesting colonies, as do concentrations of Black-browed Albatrosses near the Falklands. A local concentration, 17 species off the Valdes Peninsula on 15 September, may have been related to upwelling, as numbers of Pilot Whales were also feeding in the area. A small assemblage of 50 prions, 30 Cape Pigeons, 10 Black-browed Albatrosses and a scattering of other species near 47° 29’S, 50° 10’W on 30 September could not be attributed to any particular oceanographic conditions. Rumboll noted that storm-petrels were often found near masses of floating kelp and suggested that these mats may ‘“‘filter’’ planktonic organisms and thus enrich local feeding conditions.
Temperature preferences.—It is well established that the distribution of many seabirds is related to sea surface temperatures. Temperature preferences are not always precise and may shift seasonally, be affected by the proximity of breeding colonies, or change in response to exceptional feeding opportunities, such as may occur in the vicinity of convergences. The temperature preferences of species observed in this cruise (Figure 12) are largely in accord with those found by previous workers (e.g., Murphy, 1936; Biermann and Voous, 1950; Jehl, 1973, 1974; Watson, 1975). Thus, many common species (e.g., Daption capensis, Diomedea melanophris) occurred over a broad range. Eudyptes sp., Diomedea chrysostoma, Phoebetria palpebrata, Macronectes giganteus, Fulmarus glacialoides, Pterodroma incerta, Procellaria cinerea, Puffinus griseus, Garrodia nereis, and Larus dominicanus, were largely or entirely restricted to Subantarctic waters ( 15°C), whereas Diomedea chlororhynchos, Phoebetria fusca, Pterodroma mollis, and Puffinus gravis, occupied the Subtropical Zone (_ 18°C). The occurrence of Puffinus gravis in the Subtropical Zone is somewhat surprising, as this species typically prefers colder waters. This species is absent from shelf waters in winter (Jehl, 1974); presumably birds seen on this cruise were migrants returning from the Northern Hemisphere that had not yet reached cooler waters near the breeding grounds. The apparent preference of Larus dominicanus for cold waters is an artifact due to the proximity of land in the more southern part of the cruise route; this species rarely wanders more than 50 miles to sea.
Ws
6 8 10 72 V4 76 18 20
SS
Garroida nereis Fulmarus glacialoides Larus dominicanus Puffinus griseus Diomedea chrysostoma Pachyptila spp. Diomedea melanophris Diomedea exulans Daption capensis Procellaria aequinoctialis Eudyptes crestatus Oceanites oceanicus Phoebetria palpebrata Procellaria cinerea Pelecanoides spp. Pterodroma incerta Pterodroma mollis Phoebetria fusca
Diomedea chlororhynchos
WAIL i
Puffinus gravis
Figure 12. Temperature distribution of marine species encountered in this study. The major distribution is indicated by a solid bar, scattered records by a thin line.
Oiling.—Elsewhere Jehl (1974) has commented on the high frequency of oiling among procellariiform birds and penguins over the continental shelf of Argentina, particularly in the vicinity of major shipping lanes. Thus, it is interesting that over the open ocean, far from commercial traffic, Rumboll saw only one oiled bird, a Cape Pigeon 200 miles N of the Falklands.
Seabirds and marine mammals.—Seabirds have often been noted in the vicinity of marine mammals, particularly baleen whales, but the reports are usually anecdotal and provide little insight into the basis for the association. Opportunities to study such interactions are few and dwindling, as commercial harvesting continues to deplete whale populations.
We observed whales on 8 occasions: Globicephala melaena - 3 occasions; Balaenoptera physalus - 1; Hyperoodon planifrons -1; Physeter catodon -1 (2?), and unidentified - 1. In four cases, bird numbers increased in the vicinity of whales. In order not to disturb the whales we did not attempt to collect in the area. However, the species composition of these seabird flocks did not differ from those encountered elsewhere, suggesting that the birds and whales were responding independently to favorable feeding conditions.
16
LITERATURE CITED
BIERMANN, W. H. and K. H. Voous, 1950. Birds observed and collected during the whaling expeditions of the ‘Willem Barendsz”’ in the Antarctic, 1946-1947 and 1947-1948. Leiden, Heder
Cooke, F. and E. H. MILLs, 1972. Summer distri- bution of pelagic birds off the coast of Argentina. Ibis 114: 245-251.
JEHL, J. R., JR, 1973. The distribution of marine birds in Chilean waters in winter. Auk 90: 114-135.
JeEHL, J. R., JR. 1974. The distribution and ecol- ogy of marine birds over the continental shelf of Argentina in winter. Transactions San Diego Society of Natural History, 17: 217-234.
Murpnuy, R. C., 1936. Oceanic birds of South America, 2 vols. New York, American Museum of Natural History.
TICKELL, W.L.N. and R. W. Woops, 1972. Orni- thological observations at sea in the South Atlantic Ocean, 1954-1964. British Antarctic Survey Bulletin 31: 63-84.
Watson, G. E., et al., 1971. Birds of the Antarc- tic and Subantarctic. Antarctic Map Folio Series, Folio 14. New York, American Geo- graphical Society.
Watson, G. E., 1975. Birds of the Antarctic and Subantarctic. Washington, D.C., American Geophysical Union.
Casilla Correo 380, 8400-San Carlos de Bariloche, Rio Negro, Argentina, and Hubbs- Sea World Research Institute, 1700 South Shores Road, San Diego, California
92109.
THE NANNONISCIDAE (ISOPODA, ASELLOWA): HEBEFUSTIS N. GEN. AND NANNO ~~ S HANSEN \
Joseph F. Siebenaller and Rot ert R. ser [/
=
TRANSACTIONS
()
y
\ \
See dial= SAN DIEGO SOC rE FY Or NATURAL HISTORY
VOL. 19, NO. 2 14 OCTOBER 1977
The Nannoniscidae (Isopoda, Asellota): Hebefustis n. gen. and Nannoniscoides Hansen
Joseph F.. Siebenaller and Robert R. Hessler
ABSTRACT.—The morphologically diverse asellote isopod family Nannoniscidae Hansen 1916 is redefined and contrasted with the other major families of the superfamily Janiroidea. The bulbous fifth article of antenna I and the medial fusion of pereonites 6 and 7 are generally useful in dis- tinguishing a nannoniscid. Where these features are absent, other characters must be employed: the single major dactylar claw on pereopods II-VII, the flat triangular molar process of the mandible, uropodal shape, and the presence of major setae on the tergites of pereonites 2-4.
The desmosomatid genus Thaumastoma Hessler is referred to the Nannoniscidae. Sugoniscus Menzies and George is placed in family incertae sedis pending further study. Features of Desmosoma coalescum Menzies and George are redrawn and the species is referred to Nannoniscus.
The definition of the genus Nannoniscoides Hansen is clarified and four new species are described. Nannoniscus excavatifrons Birstein is transferred to Nannoniscoides. A morpho- logically similar new genus, Hebefustis, is described with seven new species. Nannoniscus primitivus Menzies, N. robustus Birstein and Nannoniscoides hirsutus Menzies are referred to Hebefustis.
These new descriptions are based on materials taken from benthic samples encompassing a depth range of 587-5223 m in the North and South Atlantic Ocean. The bathymetric range of Nannoniscoides is 180-4833 m; the range of Hebefustis is 587-5223 m. A list of the described species of the family is given.
The isopod superfamily Janiroidea (= Paraselloidea Wolff, 1962) is found throughout the benthic marine environment (Kussakin, 1973). Although its representatives are reasonably abundant in many shallow-water habitats, it achieves its greatest diversity in the deep sea (Wolff, 1962; Menzies et al., 1973; Hessler and Thistle, 1975). Here the superfamily has undergone a major radiation, both in terms of species richness and variety of supraspecific taxa, such that it is one of the most diverse elements in any deep-sea community (Hessler and Sanders, 1967).
The Janiroidea contains approximately 20 family in current usage. About 12 of these are to be regarded as significant. For the most part these families are easily recognized and distinctly well defined. However, the Nannoniscidae is unusual in that while there is seldom any question about which species should be included within it, there are no key features which are universally possessed by all of its members. Thus, the Nannoniscidae displays a range of morphologies (e.g., Nannoniscoides angulatus Hansen, 1916; Nannoniscus hanseni Just, 1970; and Nannonisconus latipleonus- Schultz, 1966) that causes considerable difficulty in constructing an adequate familial diagnosis.
This paper treats two genera [Hebefustis n. gen. with seven new species and Nannoniscoides Hansen (1916) with four new species] which highlight this problem in that both lack the distinctive bulbosity of the distal article of the first antenna and some lack the medial fusion of the sixth and seventh pereonites. These have generally been used as the hallmarks of the family. In order to clarify why we, and others in the past, feel these genera belong in the family, the paper redefines the Nannoniscidae and compares it to the other families.
The present study is based primarily on the extensive collections accumulated by the deep-sea sampling program of the Woods Hole Oceanographic Institution (Sanders et al., 1965; Hessler and Sanders, 1967; Sanders and Hessler, 1969). This program has made a series of sampling transects throughout the Atlantic Ocean, running out from shallow coastal waters into the abyss. Such transects are located off the northeastern United States (Gay Head-Bermuda transect), Surinam,
SAN DIEGO SOC. NAT. HIST., TRANS. 19(2):17-44, 14 OCTOBER 1977
18
northern Brazil, Argentina, Southwest Africa, Angola, Senegal, and Ireland. Additional samples have come from the Bay of Biscay (J. Allen, University of Newcastle upon Tyne), the Canary Islands (J. Allen), and the Weddell Sea (J. Rankin, University of Connecticut). A list of stations is given in Table 1.
Institutional abbreviations used in this study follow: WHOI, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA; SIO, Scripps Institution of Oceanography, La Jolla, California, USA; ZMUC, Zoological Musem, University of Copenhagen, Copenhagen, Denmark; USNM, United States National Museum, Washington, D.C., USA.
SYSTEMATICS Nannoniscidae Hansen, 1916 (Nannoniscini auctoris)
Diagnosis.— Body usually slender, less commonly broad and flat. Cephalon not fused with thorax; pereonites 5-7 not enlarged; 1-5 free, 6 and 7 frequently fused medially (Nannonisconus has pereonite 7 fused to pleon instead); often a recurved ventral medial spine present on pereonite 7 or female operculum. Eyes absent. Antenna I often 5-segmented with bulbous distal article, or unmodified and with 6 or rarely 7 segments. Antennae well separated; frons with interantennal ridges, varying from slightly to massively developed, or with rostral crest. Antenna II of male generally more robust and setose than that of female. Mandibular molar process flattened, triangular lobe with setiferous apex; palp generally present and well developed. Maxilliped with second and third segments of palp broad, approximately width of endite, segments 4 and 5 much more slender. Pereopods of normal length, with one major terminal claw; epimeres of I-IV rarely project markedly anteriorly; major anterolateral seta of pereonites 2-4 stems from tergite, not coxa of limb; pereopods V-VII not exceptionally flattened for swimming, but may have plumose natatory setae. Uropods insert ventrally, almost universally biramous, with well-developed protopod.
Type species.—Nannoniscus oblongus G. O. Sars, 1870.
References.—Nannoniscini Hansen, 1916:83; Gurjanova, 1932:50; 1933:413; Nordenstam, 1933:251; Menzies, 1962a:29; 1962b:133; Wolff, 1962:31; Menzies and George 1972:95.
Remarks.—This definition is lengthy in contrast to some of those in the past (Hansen, 1916; Gurjanova, 1932, 1933; Nordenstam, 1933; Menzies, 1962a, 1962b; Wolff, 1962; Menzies and George, 1972), but such detail is necessary in view of the fact that no single feature uniformly diagnoses the family. The definition retains the essential features of Hansen’s definition of the group Nannoniscini (1916), while accommodating the new morphologies that have been discovered since his work.
Two features are commonly useful in distinguishing a nannoniscid—the bulbous distal article on the first antenna and the medial fusion of pereonites 6 and 7. However, not uncommonly one and rarely both of these features are absent (Austroniscus, Nannoniscoides biscutatus, N. coronarius). In such cases other characters must be utilized.
Nannoniscid pereopods II-VII have only one major dactylar claw, which separates them from the Janiridae,', Jaeropsidae, Acanthaspididae, Microparasel- lidae, and Antiasidae.
A yet more useful feature is the flat, triangular molar process, which is found in only three other families: Macrostylidae, Pseudomesidae, and Desmosomatidae. Even the Thambematidae, which are similar to nannoniscids in so many ways, can be differentiated in this respect.
1Janthura abyssicola Wolff, 1962 is a janirid that blurs the distinction between the two families in two ways. The pereopodal dactyli have only one major claw, and the mandibular molar process is triangular. As Wolff pointed out, these features are quite aberrant within the Janiridae, but the species shows other features that document its inclusion. Important in the present context are the bifid lateral margins of pereonites 1-3, relatively slender maxillipedal palp articles (segments) 2 and 3, large biramous uropod, and typical janirid body shape.
TABLE 1. Station data.
Depth
Station (m) Latitude Longitude WHO! 95 3753 S8r3ouN 68°32' W 122 4833 35eol" IN 65°32' W 126 3806 395 SiN 66°47' W 142 1624-1796 10°30' N VS WN 155 3730-3783 00°03.5' S 27°48' W 156 3459 00°45' S 29°26' W 159 834-939 07°58' S 34°22' W 162 1493 OES 34°06' W 167 943-1007 OLS 34°17' W 169 587 08°03' S 34°24' W 202 1427-1643 OePOs7 S I2Aln” (E 08°56' S W275 [E
245 2707 2\5) BSE | eS 5370174 WW
247 5208-5223 Ale eyeh" S 48°58.1' W
256 3906-3917 37740:9" S Bye Ses Way
328 4426-4435 50°04.7' N 15°44.8' W
Chain 35,
Dredge 12 769-805 07°09' S 34°25' W ALLEN S33 1784 43°40.8' N 03°36' W
Macrostylids are easily distinguished by several special features, including distinctive body form, extensive elaboration of sensory setae on the first antenna of mature males, close packing of pereonites 1-3, unique adaptation of pereopods I-III for living beneath the sediment surface, and styliform uropods.
The Pseudomesidae can be differentiated on the basis of their compact, uniramous uropod and lack of both squama on the second antenna and palp on the mandible. Micromesus, which Birstein (1963a) placed in the Pseudomesidae, does have a bulbous first antenna, but is similar in no other way.
Differentiation from the Desmosomatidae is a difficult problem. There is nothing in the diagnosis of this family (Hessler, 1970) to exclude Austroniscus or the two above-mentioned species of Nannoniscoides. Unquestionably, the two families are very closely related, yet viewing all the species as a whole, they do fall into two subgroups. It is not surprising that it is the species which should be regarded as relatively primitive within the Nannoniscidae that blur the distinctions (the secondary amplification of swimming morphology in Austroniscus notwith- standing).
Our diagnosis of the Nannoniscidae does include one feature that objectively discriminates the two families. The major seta on the anterolateral corner of pereonites 2-4 stems from the tergite as opposed to the coxa. Two exceptions to this are Nannoniscus muscarius and N. perunis Menzies and George, 1972. Here the seta arises from the coxa of pereopod II. In both species the coxa of this limb projects well forward, whereas in nannoniscids in general the coxae do not extend much beyond the tergite. In desmosomatids the coxae of pereopods II-IV always project in front of the tergite. Thus, the positioning of this seta may reflect the general development of the coxal epimere.
Generic composition.—Nannoniscus Sars, 1870; Austroniscus Vanhoffen, 1914 (partim); Nannoniscoides Hansen, 1916; Nannonisconus Schultz, 1966; Thaumastosoma Hessler, 1970; Hebefustis n. gen.
20
Figure 1. Nannoniscus sp., Anton Bruun 11 Sta. 108, brooding female (USNM 120965, identified as Desmosoma coalescum Menzies and George, 1972). A. right antenna I, lateral view; B. left uropod, in situ; C. right pereopod I, in situ; D. right pereopod II, in situ. Nannoniscus coalescus, Anton Bruun 11 Sta. 179 (holotype, Desmosoma coalescum Menzies and George, 1972, USNM 120964). E. right antenna I, dorsal view; F. pereonites 1-4; G. right uropod, in situ, exopod somewhat foreshortened in this perspective.
Synonomy.—Nannoniscella Hansen, 1916, with N. groenlandica Hansen, 1916, and N. vinogradovi Gurjanova, 1950 is a synonym of Austroniscus Vanhoffen, 1914 (by Birstein, 1962:33-34). The monotypic Austroniscoides Birstein, 1963b (A. bougainvillei Birstein, 1963b) is a synonym of Janthura (by Menzies and George, 1972:95). Austrofilius Hodgson, 1910, is a synonym of Neojaera Nordenstam, 1933 (by Menzies, 1962a:74-75).
We concur with Menzies and George (1972) in the transfer of Austroniscoides Birstein, 1963b from the Nannoniscidae to the Janiridae, and the synonomy of Austroniscoides with Janthura Wolff, 1962. Birstein (1962, 1963a) included Austrofilius Hodgson, 1910 in the Nannoniscidae. However, we follow Menzies (1962a:74-75) and Wolff (1962:206) in the removal of Austrofilius from the family, and its synonomy with Neojaera Nordenstam, 1933.
The monotypic genus Sugoniscus Menzies and George, 1972 was placed by them in the Nannoniscidae, requiring them to broaden the familial diagnosis in order to accommodate it. However, Sugoniscus does not show even superficial resemblance to any nannoniscid; it bears no features that ally it to this family in
72)
particular. In Sugoniscus the cephalon and mouthpart appendages are highly modified to accommodate a possibly parasitic mode of existence. The genus lacks interantennal ridges, and the antennae are much more laterally placed than is typical of the Nannoniscidae. The first antenna is unmodified. Pereonites 6 and 7 are unfused, and there are no ventral spines. The high degree of fringing ornamenta- tion is unknown in the Nannoniscidae. Its inclusion renders the concept of the family useless. Therefore, we relegate Sugoniscus to family incertae sedis pending further study.
By the criterion of the seta on the anterolateral corner of pereonites 2-4, the genus Thaumastosoma, which Hessler (1970) placed in the Desmosomatidae, should be removed to the Nannoniscidae. This genus also possesses midventral spines on pereonite 7 and the female operculum. Such a feature is common in the Nannonis- cidae, but is otherwise unknown among the Desmosomatidae.
Species realignment.—Nannoniscus primitivus Menzies, 1962b, Nannoniscus robustus Birstein, 1963a, and Nannoniscoides hirsutus Menzies, 1962b are referred to Hebefustis (see below). Nannoniscus excavatifrons Birstein, 1970 is referred to Nannoniscoides (see below).
Previously, two species have been removed from the family: Nannoniscus bicuspis Sars, 1885 to Haploniscus by Richardson (1908:75); and Austroniscus ectiformis Vanhoffen, 1914 to Caecianiropsis by Menzies and Pettit (1956:442).
Desmosoma coalescum Menzies and George, 1972 should also be placed in the Nannoniscidae, because it has pereonites 6 and 7 fused, and a 5-segmented first antenna having a bulbous fifth article. Menzies and George’s original illustration (Menzies and George, 1972, fig. 31B) is incorrect regarding antenna I, based on our examination of the holotype. The fifth article in their drawing is in reality a lateral projection of the fourth, and the bulbous fifth was omitted (Fig. 1E). In addition, their fig. 31A erroneously shows epimeres on the anterior four pereonites. Other aspects of this species morphology are consistent with the diagnosis of the Nan- noniscidae as given here, and should be considered as Nannoniscus coalescus. The additional two specimens designated D. coalescum (USNM. 120965) by Menzies and George are also nannoniscids, but they differ from the holotype inter alia in the structure of the first pereopod and in having a large recurved ventral medial spine anterior to the operculum, and therefore are not this species, but are an undescribed species of Nannoniscus. Table 2 gives the names of species referable to Nannoniscidae.
Nannoniscoides Hansen, 1916
Type species.—Nannoniscoides angulatus Hansen, 1916.
Diagnosis.— Antenna I unspecialized, 6- (or rarely 7-) segmented; segments 3-5 well developed; penultimate segment lacking lateral projection; distal segment with simple, unmodified terminal aesthetasc. Pleon with posterolateral spines. Operculum (female pleopod II) elongate, with concavity and calcareous fringe at midline of distal edge; operculum approximately 0.85 or more dorsal length of pleon. Pereopods I-III lack epimeres. Pereopod I of medium robustness; ventral surface of carpus and propodus with thin setae, except for distal robust seta on carpus. Cephalon with pointed lateral lappets. Pereonites 6 and 7 may be free or fused. Pereonite 2 with robust seta on anterolateral corners. Medial lobes of male pleopods I taper distally. Uropod length averages 0.3 length of pleon. Body depressed; length roughly three times tergal width of pereonite 2.
Remarks.—The only other nannoniscid genera with a 6-segmented, unmodified antenna I are Austroniscus and Thaumastosoma. Nannoniscoides differs in having pleonal posterolateral spines, and in lacking an epimere on the coxa of pereopod I. Thaumastosoma displays a sexual dimorphism of pleonar shape not seen in Nan- noniscoides. In addition the female operculum of Austroniscus is much smaller in
22
TABLE 2. A compilation of the nannoniscid species (* indicates generic type species).
Genus Species
Nannoniscus acanthurus Birstein, 1963a; aequiremis Hansen, 1916; affinis Hansen, 1916; analis Hansen, 1916; arcticus Hansen, 1916; armatus Hansen, 1916; australis Vanh6ffen, 1914; bidens Vanhoffen, 1914; camayae Menzies, 1962b; caspius Sars, 1897; coalescus (Menzies and George, 1972); crassipes Hansen, 1916; detrimentus Menzies and George, 1972; hanseni Just, 1970; inermis Hansen, 1916; laevis Menzies, 1962b; /Jaticeps Hansen, 1916; minutus Hansen, 1916; muscarius Menzies and George, 1972; ob/ongus* Sars, 1870 (figured 1899); ovatus Menzies and George, 1972; perunis Menzies and George, 1972; plebejus Hansen, 1916; reticulatus Hansen, 1916; simplex Hansen, 1916; spinicornis Hansen, 1916; tene//us Birstein, 1963a
Nannonisconus latipleonus* Schultz, 1966
Austroniscus acutus Birstein, 1970; groenlandicus (Hansen, 1916); karamani Birstein, 1962; ovalis* Vanhoffen, 1914; rotundatus Vanhoffen, 1914; vinogradovi (Gurjanova, 1950)
Nannoniscoides angulatus* Hansen, 1916; biscutatus n. sp.; Coronarius n. sp.; excavatifrons (Birstein, 1970); gigas n. sp.; latediffusus n. sp.
Hebefustis alleni n. sp.; cornutus n. sp.; dispar n. sp.; hexadentium n. sp.; hirsutus (Menzies, 1962b); mollicellus n. sp.; par n. sp.; primitivus (Menzies, 1962b); robustus (Birstein, 1963a); vafer* n. sp.
Thaumastosoma distinctum (Birstein, 1963a); platycarpus* Hessler, 1970; tenue Hessler, 1970
relation to the size of the pleon, a reflection of the broadened swimming morphology of this genus. The insertions of the posterior pereopods in Austroniscus become more medial as one moves posteriorly, whereas in Nannoniscoides the posterior insertions are all equally far from the midline.
Nannoniscoides females closely resemble Hebefustis n. gen. in general body shape, particularly in the shape of the pleon. They may be easily distinguished by the number of segments in the first antenna, the robustness of the setae on the propodus and carpus of pereopod I, the form of the cephalic lappets, and the shape of the operculum.
This genus contains the following species: Nannoniscoides latediffusus, n. sp.; N. biscutatus, n. sp.; N. coronarius, n. sp.; N. gigas, n. sp.; N. angulatus Hansen, 1916, type species; N. excavatifrons (= Nannoniscus excavatifrons Birstein, 1970). Nannoniscoides hirsutus Menzies, 1962b is transferred to Hebefustis (see discus- sion in that section). The reassignment of Nannoniscus excavatifrons Birstein, 1970 to Nannoniscoides is based on its obvious similarity to the type species. Its inclusion provides a continuum of morphological features from-the extreme of the type species, described from only male specimens (Hansen, 1916; Just, 1970; Gurbunov, 1946 mentions the occurrence of N. angulatus in the Kara Sea, but provides only biogeographic information) to the species described here from females and immature males.
The type species, Nannoniscoides angulatus, is distinct in several respects, including length-width ratios, the ventral medial projection of pereonite 7 and the shape of the pleon. Nannoniscoides excavatifrons and a male of N. latediffusus n.sp. closely resemble N. angulatus in head structure and the lengthening of the lateral lobes of pereonite 2. Nannoniscoides excavatifrons has a 6-segmented unmodified antenna I; N. latediffusus has an unmodified antenna I which is unique in being 7-segmented in the male. The shape of the pleon, the length-width ratios, and the type of setation on the propodus and carpus of pereopod I of N. excavatifrons clearly link the new species described here with N. angulatus. These features strengthen the case for the assignment of these species to Nannoniscoides, a decision based principally on the 6-segmented structure of antenna I (Just, 1970),
23
.
N. angulatus « a
— = ~ SEP =. 99° MES 30° ~
LE 358 N.angulatus j
or.) 10°
° © 20)
ox
,
eS N. angulatus «
Oy
H. par « H.alleni
OL latediffusus oi . Hcornutus
: —s
= Sly
tales
Of
H.allenia (Ox
| N. biscutat us
on par
| ie latediffusus
N coronarius H.vafer H mollicellus se 403 . =30? aH hirsutus 40° 20° 10° ar 10 30°
Figure 2. Nannoniscoides and Hebefustis: geographical distribution of species in the Atlantic Ocean.
the shape of the pleon, and the pointed cephalic lappets.
Sexual dimorphism.—The sexual dimorphism exhibited in this genus is the most extreme seen in the Nannoniscidae. Mature, or nearly mature males may have a more massively developed cephalon than females (cf. male and female of N. latediffusus), and more strongly produced lateral lobes of pereonite 2. Typically, the primary sexual differences in nannoniscids (aside from the pleopod differences) are merely the more robust male second antenna and differences in overall body and pleonar dimensions and ratios.
In Nannoniscoides there is also an indication of sexual differences in the first antenna, unique in the Nannoniscidae. These differences may be manifest in the number of aesthetascs and relative lengths of segments 5 and 6 (cf. N. biscutatus). (The number of segments varies between the male and female of N. latediffusus.)
24
However, the occurrence of extreme sexual dimorphism within the genus appears to be variable; one finds species in which sexual dimorphism is expressed mainly in the robustness of the second antennae, as is commonly the case in other genera (see drawing of undescribed male, Nannoniscoides No. 5, Fig. 6).
Distribution.—Nannoniscoides angulatus: North Atlantic, north of the Faroes, 1284 m (Hansen, 1916); northernmost part of the Kara Sea, 698 m (Gurbunov, 1946); Jorgen Bronlund Fjord, Greenland, 160-180 m (Just, 1970). Nannoniscoides excavatifrons: northwest Pacific, in the Kurile-Kamchatka area, 1440-1540 m (Birstein, 1970). Nannoniscoides latediffusus: northwest Atlantic, equatorial south- west Atlantic, 587-4833 m. Nannoniscoides biscutatus: equatorial southwest Atlantic, 3459-3783 m. Nannoniscoides coronarius: equatorial southwest Atlantic, 1493 m. Nannoniscoides gigas: South Atlantic, Argentine Basin, 3909-3917 m. Nannoniscoides No. 5: South Atlantic, Argentine Basin, 2707 m. The map in Fig. 2 shows the distribution of species of Nannoniscoides in the Atlantic Ocean.
Nannoniscoides biscutatus n. sp. Figure 3
Holotype.—WHOI 156, brooding female, 1.7 mm long, USNM 169386.
Paratype.—WHOI 155, male, 2.0 mm long, USNM 169387; WHOI 156, 1 preparatory female, 1 juvenile female, WHOI 155, 2 brooding females, SIO.
Distribution.—Equatorial Atlantic Ocean, 3459-3783 m.
Etymology.—bis, Latin, in two ways, twice; scutatus, Latin, armed with a shield.
Diagnosis.— Antenna I terminal segment elongate, not inflated, length to width ratio (1/w) 5.0 (holotype), 3.6 (allotype). Segment 6, 0.5 (holotype), 0.4 (allotype) times length of segment 2. Combined length of segments 3-6, 1.4 (holotype), 1.89 (allotype) times length of segment 2. Segment 5 of male much longer than segment 6; segment 5 with two distal aesthetascs, segment 6 with one. (Differs from female which has single aesthetasc on segment 6 and segment 6 longer than segment 5.)
Pereonites 6 and 7 free.
Pleon with posterolateral processes (teeth), 0.67 (holotype and allotype) removed from anterior edge. Width of pleon between midpoints of concavities formed by teeth 0.79 (holotype), 0.84 (allotype) width of pleon; pleon 1/w 1.06 (holotype), 1.10 (allotype). Pleon 0.67 (holotype), 0.69 (allotype) times width of pereonite 2.
Female operculum 1/w 1.6; 1.0 times length of pleon (excluding pleonal somite 1).
Male pleopod I sides from proximal end to lateral lobes relatively straight. Lateral lobes forming posteriorly projecting spines. Outer margins of medial lobes convex, tapering to broad points distally. Pleopod I 1/w 5.6; 0.8 length of pleon.
Uropod length 0.4 (holotype and allotype) length of pleon. Endopod 1/w 4.0 (holotype and allotype). Exopod 1/w 4.0 (holotype and allotype). Endopod length 1.8 (holotype and allotype) times length of protopod.
Cephalic keels (on inner margins bordering antennae) not strongly developed. Cephalic width 0.8 times that of pereonite 2.
Body length 3.3 (holotype), 3.7 (allotype) times tergal width of pereonite 2.
Remarks.—Nannoniscoides biscutatus n. sp. may be distinguished from N. coronarius n. sp., the other member of the genus which lacks medial fusion of pereonites 6 and 7, by the less developed and more widely separated cephalic keels of N. biscutatus, as well as by its more elongate uropodal rami, the narrower, more elongate form of the articles of antenna I and the somewhat more elongate body form.
25
Figure 3. Nannoniscoides biscutatus n. sp., WHOI 156. A. brooding female (holotype), dorsal view; B. brooding female (holotype) right antenna I, lateral view; C. brooding female (holotype) operculum, D. posterior margin of operculum; E. juvenile female right pereopod I. WHOI 155. F. male (paratype) dorsal view; G. male (paratype) left antenna I, dorsal view; H. male (paratype) left uropod, in situ, I. male (paratype) pleon, ventral view.
Nannoniscoides gigas n. sp. Figure 4
Holotype.—WHOI 256, preparatory female, 2.8 mm long, USNM 169388.
Paratype.—WHOI 256, 1 additional preparatory female, SIO.
Distribution.— Argentine Basin, South Atlantic Ocean, 3909-3917 m.
Etymology.—Latin, giant.
Diagnosis.— Antenna I terminal segment inflated, length to width ratio (1/w) 2.0; length of segment 6, 0.5 times length of segment 2; combined length of segments 3-6, 0.3 times length of segment 2.
Pereonites 6 and 7 fused.
Pleon with posterolateral processes (teeth) 0.71 removed from anterior edge. Width of pleon between midpoints of concavities formed by teeth 0.76 width of pleon; pleon 1/w 0.93; pleon width 0.74 times width of pereonite 2.
Female operculum 1/w 1.3; 0.8 times length of pleon.
26
GF A vee } ——" ) l NY \ \ W2 aaa ae 4 Nelo ZL ns UA a oe & & u /V/ \ i ye ES a —t—_, } a D ~< | / | / ee) \ Sas) 7, Wz Ae oh
Figure 4. Nannoniscoides gigas n. sp., WHOI 256, preparatory female (holotype). A. dorsal view; B. right pereopod I; C. right antenna I, lateral view; D. posterior margin of operculum; E. pleon, ventral
vi1ew.
Uropod 0.2 times length of pleon. Endopod 1/w 2.6; exopod 1/w 3.5; endopod length 1.6 protopod length.
Cephalic keels not well developed. Cephalic width 0.7 times that of pereonite 2.
Body length 3.0 times tergal width of pereonite 2.
Remarks.—Of the species with fused pereonites 6 and 7, N. gigas is only similar to N. latediffusus. Nannoniscoides gigas differs in having the pleonal posterolateral teeth positioned much more posteriorly, less elongate distal segments on antenna I and a somewhat shorter and broader female operculum.
Nannoniscoides coronarius Nn. sp. Figure 5
Holotype.—WHOI 162, brooding female, 1.4 mm long, USNM 169389.
Other material.— Holotype female only.
Distribution.—Equatorial southwest Atlantic Ocean, 1493 m.
Etymology.—Latin, relating to a crown or garland.
Diagnosis.— Antenna I terminal segment relatively narrow, not inflated, length to width ratio (1/w) 2.6; segment 6, 0.3 times length of segment 2. Combined length of segments 3-6, 1.3 times length of segment 2.
Pereonites 6 and 7 free.
Pleon with posterolateral processes (teeth) 0.73 removed from anterior edge. Width of pleon between midpoints of concavities formed by teeth 0.68 width of pleon. Pleon 1/w 0.81; width 0.79 times width of pereonite 2.
Female operculum 1/w 1.6; approximately as long as pleon.
Uropod length 0.3 length of pleon; endopod 1/w 2.8; exopod 1/w 2.1. Endopod length 1.6 times protopod length.
Distinct cephalic keels, located on surface of frons rather than on its lateral margins. Cephalic width 0.9 times that of pereonite 2.
27
Figure 5. Nannoniscoides coronarius n. sp., WHOI 162. A. brooding female (holotype), dorsal view; B. brooding female (holotype) right antenna I; C. brooding female (holotype) left uropod, in situ; D. brooding female (holotype) operculum; E. posterior margin of operculum.
Body length 3.1 times tergal width of pereonite 2.
Remarks.—The medially positioned paired keels on the surface of the frons are thus far unique to this species. It and N. biscutatus n. sp. may be readily distin- guished from all others of the genus by the lack of medial fusion of pereonites 6 and 7. Nannoniscoides coronarius differs:from N. biscutatus in having more closely spaced cephalic keels, more compact uropodal rami and articles of antenna I, and a less elongate body form.
Nannoniscoides latediffusus n. sp. Figure 6
Holotype.—WHOI 169, brooding female, 2.0 mm long, USNM 169390.
Paratype.—WHOI 169, male, 1.7 mm long, USNM 169391, and preparatory female, USNM 169404; WHOI 169, 10 spec., SIO.
Other material.—WHOI 122, 1 spec.; WHOI 126, 1 spec.; WHOI 159, 1 spec.; WHOI 167, 2 spec.; WHOI Chain 35, Dredge 12, 1 spec., SIO.
Distribution.—Northwest Atlantic Ocean, 587-4833 m.
Etymology.—late, Latin, broadly or widely; diffusus, Latin, distributed or spread out.
Diagnosis.— Antenna I 6-segmented (holotype), 7-segmented in adult male (see Remarks); length to width ratio (1/w) of terminal segment 3.1 (holotype). Segment 6, 0.7 times length of segment 2. Combined length of segments 3-6, 1.4 times length of segment 2.
Pereonites 6 and 7 fused.
Pleon with posterolateral processes (teeth) 0.55 (holotype), 0.59 (allotype) removed from anterior edge. Width of pleon between midpoints of concavities formed by teeth 0.79 (holotype), 0.90 (allotype) times width of pleon; pleon 1/w 0.93
28
Figure 6. Nannoniscoides latediffusus n. sp., WHOI 169. A. brooding female (holotype), dorsal view; B. preparatory female (paratype) right uropod, in situ; C. brooding female (holotype) right antenna I, dorsolateral view; D. brooding female (holotype) pleon, ventral view; E. male (paratype), dorsal view: F. male (paratype) right antenna I, dorsal view; G. male (paratype) left uropod, in situ; H. male (paratype) pleopods I, in situ; I. WHOI 167 juvenile male, right antenna I, dorsal view.
(holotype), 1.0 (allotype). Pleon 0.73 (holotype and allotype) times width of pereonite Dr
Female operculum 1/w 1.6; 0.9 length of pleon.
Male pleopods I narrowly rounded distally; lateral lobes with hook-like process; 1/w 4.4; pleopod 0.8 times length of pleon.
Uropod length 0.3 (paratype female and paratype male) times length of pleon. Endopod 1/w 3.4 (paratype female), 3.8 (paratype male). Exopod 1/w 3.2 (paratype female), 4.3 (paratype male). Endopod length 1.5 (paratype female and male) times protopod length.
Cephalic keels (on inner margins bordering antennae) well developed (see Remarks). Cephalic lappets of male highly developed. Cephalic width 0.9 times that of pereonite 2 (holotype and allotype).
29
Figure 7. Nannoniscoides No. 5, WHOI 245, undescribed male. A. dorsal view: B. lett antennae | and Il, dorsolateral view; C. lett uropod; D. pleopods 1; E. left antenna I, dorsolateral view: F. left pereopod I, iv situ; G. pleon, ventral view.
Body length 3.2 (holotype), 2.9 (allotype) times tergal width of pereonite 2.
Remarks.—The uropods are broken off the holotype female. The male differs markedly from the female in its well-developed cephalon (keels and lappets), antenna I (7-segmented with 3 aesthetascs, one from segment 7 and two from segment 6, rather than 6-segmented with 1 aesthetasc in the female) and in the development of pereonites 2 and 3 (the projecting lobes and setae). This dimorphism of the first antenna is unusual in the Nannoniscidae. In other nannoniscid genera the only antennal dimorphism is expressed in the robustness and setation ot antenna II. P
The male specimens of this species (W HOI 169 and WHOI 167) are of particular note. They display a continuum of body form from that of the female to that charac- teristic of the adult male of the generic type species (a single male), N. angulatus. Pleopods I also show a transition to more highly developed lateral lobes and hook- like processes in the mature male ot N. latediffusus. There is also a transition from the 6-segmented female antenna to the 7-segmented copulatory male antenna through the 6-segmented antenna of the juvenile male of WHOI 167.
This species has an exceptionally broad geographic and bathymetric range. The possibility remains that N. latediffusus consists of sibling species possessing more restricted depth ranges; however, no clear-cut morphological evidence permits such a differentiation.
30
Hebefustis n. gen.
Diagnosis.— First antenna 5-segmented, distal segment elongate and somewhat inflated; segment 4 lacks a lateral projection, segments 3 and 4 well developed, not hidden.
Pleon with posterolateral spines.
Operculum (female pleopod II) ovoid to pear-shaped; length about 0.66 of length of pleon (measured in dorsal view); distal margin straight without calcareous fringing margin.
Anterior three pereopods lack epimeres; pereopods of medium robustness. Pereopod I: ventral surface of carpus and propodus have robust setae.
Rounded cephalic lappets.
Male pleopod I widest proximally; sides convex proximally, concave to straight distally; limb often flared distally.
Uropods relatively short; uropod length about 0.25 length of pleon.
Pereonites 6 and 7 fused medially.
Body depressed; length about 3.8 tergal width of pereonite 2.
Type species.—Hebefustis vafer n. sp.
Etymology.—Hebes, Latin, meaning blunt; fustis, Latin, meaning club. The name is masculine, and was suggested by the shape of the terminal articles of the first antenna.
Remarks.—One cannot tell from Menzies’ (1962b) descriptions whether H. hirsutus and H. primitivus have pointed or rounded cephalic lappets. The holotype (sole specimen) of H. hirsutus cannot be found (R. J. Menzies, pers. comm.). The condition of the sole specimen of H. primitivus does not allow a judgment as to the shape of the cephalic lappets.
The females of this genus are similar to those of Nannoniscoides, particularly in the overall body shape, the posterolateral processes on the pleon, and the general robustness of the first pereopods. The two genera may be distinguished on the basis of the structure of the first antenna (6-segmented in Nannoniscoides, 5-segmented in Hebefustis), the type of setae on the propodus and carpus of pereopod I (thin in Nannoniscoides, robust in Hebefustis), the shape of the female operculum (elongate, with a distal concavity at the midline in Nannoniscoides; pear-shaped to ovoid in Hebefustis, with a straight distal margin), and the shape of the lateral lappets of the cephalon (pointed in Nannoniscoides, rounded in Hebefustis).
Several species of Nannoniscus also closely resemble Hebefustis (N. bidens Vanhoffen, 1914, N. camayae Menzies, 1962b, and N. minutus Hansen, 1916). These species have acute posterolateral pleonal processes and a 5-segmented antenna I. However, the first antennae of these species differ from Hebefustis in that the fourth segment of the Nannoniscus species has a large lateral projection. In addition, NV. minutus bears a large recurved ventral medial spine anterior to the operculum.
This genus contains the following species: Hebefustis vafer n. sp., type species; H. primitivus (= Nannoniscus primitivus Menzies, 1962b); H. robustus (= Nan- noniscus robustus Birstein, 1963a); H. mollicellus n. sp.; H. par n. sp.; H. alleni n. sp.; H. hirsutus (= Nannoniscoides hirsutus Menzies, 1962b); H. cornutus n. Sp; dispar n. sp.; H. hexadentium n. sp.
These species can be subdivided into two groups, one comprised of the first six species, and the other of the remaining four.
The cluster containing H. cornutus, H. dispar, H. hexadentium, and H. hirsutus has acute processes on the posterolateral margins of pereonites 6 and 7. These species differ from one another in the following ways: H. hexadentium lacks a robust seta on the corners of pereonite 2; the other species have a robust seta. They also differ in the shape of segment 5 of antenna I, and in the ratios formed describing the pleonal features.
31
The remaining species (H. vafer, H. primitivus, H. robustus, H. mollicellus, H. par, and H. alleni) do not have acute posterolateral processes on the corners of pereonites 6 and 7. Within this group the species display a high degree of similarity. Where pereopod I is available on the specimens, differences often occur in the seta- tion patterns of the propodus and carpus between species. However, there may be differences in the number of setae between the right and left pereopods of the same individual, as well as intraspecific differences. For this reason, the setation pattern is not a reliable diagnostic character for specific differences. Differentiation among these species must be made on the somewhat subtle basis of ratios of the dimen- sions of body parts, particularly of the antenna I and the pleon.
Nannoniscus primitivus Menzies (1962b), N. robustus Birstein (1963a), and Nannoniscoides hirsutus Menzies (1962b) should be transferred to Hebefustis.
Nannoniscus robustus: The complete set of drawings given by Birstein allows unambiguous placement in Hebefustis. Inter alia, the structure of the 5-segmented antenna I, the robust setae of the carpus and propodus of pereopod I, and the shapes of the plecn and the female pleopod II match precisely the diagnostic characters of the genus.
Nannoniscus primitivus: The structure of the 5-segmented antenna I and the shape of the male pleopod I are clearly characteristic of Hebefustis. The pleon is somewhat unusual in having two pairs of acute processes. However, this feature is similar to the double vertices on the pleon of the male of H. cornutus.
Nannoniscoides hirsutus: The type specimen cannot be found (R. J. Menzies, pers. comm.), and hence, certain difficulties arise in placing this species in Hebefustis. The primary difficulty is the number of segments in antenna I. In Menzies’ figure (1962b, fig. 30c), a dorsal view of the holotype, the first antenna is drawn 5-segmented, the condition in Hebefustis. Supporting evidence for the placement of this species in Hebefustis is found in the robust setae of the propodus of pereopod I, the acute posterolateral processes on pereonites 6 and 7 (similar to H. cornutus, H. dispar, and H. hexadentium), and the structure of the distal end of the male pleopod I, which is somewhat squared-off.
Distribution.—Hebefustis alleni: Bay of Biscay and northeast Atlantic, 1623-1796 m. Hebefustis cornutus: northwest Atlantic, 3753-3806 m. Hebefustis dispar: southeast Atlantic, 1427-1643 m. Hebefustis hexadentium: Argentine Basin, South Atlantic Ocean, 5024 m (Menzies, 1962b). Hebefustis hirsutus: South Atlantic Ocean, 5024 m (Menzies, 1962b). Hebefustis mollicellus: equatorial South Atlantic, 943-1007 m. Hebefustis par: northeast, equatorial and South Atlantic, 3459-4435 m. Hebefustis primitivus: Caribbean, North Atlantic, 2868-2875 m (Menzies, 1962b). Hebefustis robustus: northwest Pacific, 5461-5690 m (Birstein, 1963a). Hebefustis vafer: equatorial southwest Atlantic, 587 m.
The map in Fig. 2 shows the distribution of the species of Hebefustis occurring in the Atlantic Ocean.
Hebefustis vafer n. sp. Figures 8 and 9
Holotype.—WHOI 169 (type locality), preparatory female, 2.3 mm long, USNM 169392.
Paratype.—WHOI 169, copulatory (?) male, 1.8 mm long, USNM 169393; WHOI 169, 18 other spec., ZMUC, SIO.
Distribution.—Equatorial southwest Atlantic Ocean, 587 m.
Etymology.—Latin, artful, sly or crafty.
Diagnosis.— Antenna I segment 5 thin and elongate; length to width ratio (1/w) 4.1 (holotype), 4.0 (allotype); length segment 5, 0.8 (holotype), 0.9 (allotype) length segment 2. Pereonites 6 and 7 with no posterolateral projection. Pereonite 4 1/w 0.6
32
Figure 8. Hebefustis vafern.sp., WHOI 169. A. preparatory female (holotype), lateral view; B. prepara- tory female (holotype), dorsal view; C. preparatory female (holotype) right antenna I, dorsal view; D. preparatory female (holotype) pleon, ventral view; E. preparatory female (holotype) right uropod, in situ; F. male (paratype), dorsal view; G. male (paratype) right antennae I and II, dorsal view; H. male (paratype) right antenna I, dorsal view; I. male (paratype) left uropod, in situ; J. male (paratype) pleopods I.
(holotype), 0.5 (allotype); width 0.9 (holotype), 0.8 (allotype) times tergal width of pereonite 2; sides approximately straight. Pereonite 2 with robust seta on anterolateral corners.
Pleon with acute posterolateral processes (teeth) approximately 0.6 (holotype and allotype) distant from anterior edge; sides of pleon anterior to teeth relatively straight (straight with slight concavity before teeth in male). Pleon width between midpoints of concavities formed by teeth 0.9 (holotype), 1.0 (allotype) pleon width. Pleon 1/w 1.1 (holotype and allotype). Pleon width 0.9 (holotype and allotype) times width of pereonite 2.
33
Figure 9. Hebefustis vafer n. sp., WHOI 169, brooding female. A. left pereopod I; B. left pereopod IT; C. right maxilliped; D. right mandible; E. distal portion of left mandible.
Female operculum somewhat ovoid; 1/w 1.2; 0.7 length of pleon (measured in dorsal view).
Male pleopod I 1/w 4.3; 0.7 length of pleon; sides constricted proximal to lateral lobes, which are broadly flared.
Body length 4.2 (holotype), 4.3 (allotype) times tergal width of pereonite 2.
Remarks.—Of the species which lack posterolateral spines on pereonites 6 and 7, H. vafer n. sp. is most similar to H. mollicellus n. sp. The bodies of these two species are somewhat more elongate than those of H. par n. sp. and H. alleni n. sp. Hebefustis vafer differs from H. mollicellus in having a more elongate article 5 of antenna I; the pleonal posterolateral teeth are more anteriorly placed in the female and the posterior portion of the pleon does not taper as sharply. The male of H. vafer is much narrower in pereonites 4-5 relative to the female and the male pleopods differ between the two species in length-width ratios. The distal margin of pleopods I are broadly flared in H. vafer.
34
Figure 10. Hebefustis mollicellus n. sp., WHOI 167. A. brooding female (holotype), dorsal view; B. brooding female (holotype) right antenna I, dorsal view; C. brooding female (holotype) pleon, ventral view; D. preparatory female right pereopod I; E. brooding female (holotype) right uropod, in situ; F. male (paratype), dorsal view; G. male (paratype) left antenna I, lateral view; H. immature male (paratype) pleopods I; I. male (paratype) right pereopod VI, in situ; J. male (paratype) left uropod, in situ.
Hebefustis mollicellus n. sp. Figure 10 Holotype.—WHOI 167, brooding female, 2.0 mm long, USNM 169394. Paratype.—WHOI 167, immature male, 1.5 mm long, USNM 169395; WHOI
167, 2 spec. and 1 frag., SIO. Distribution.—Equatorial South Atlantic Ocean, 943-1007 m. Etymology.—Latin, dainty or little.
35
Diagnosis.— Antenna I segment 5 length to width ratio (1/w) 3.2 (holotype), 3.3 (allotype); 0.7 (holotype), 0.9 (allotype) times length of segment 2.
Pereonites 6 and 7 without acute posterolateral processes. Pereonite 4 1/w 0.55 (holotype and allotype); sides gently concave; slightly broader anteriorly. Width 0.9 (holotype), 0.85 (allotype) width of pereonite 2. Pereonite 2 with robust seta on anterolateral corners.
Pleon with acute posterolateral processes (teeth) 0.7 (holotype), 0.6 (allotype) removed from anterior edge. Sides of pleon anterior to teeth straight, nearly parallel. Pleonal width between midpoints of concavities formed by teeth 0.85 (holotype), 0.87 (allotype) times width of pleon. Pleon 1/w 1.2 (holotype), 1.1 (allotype). Width of pleon 0.9 (holotype), 1.0 (allotype) times width of pereonite 2.
Female operculum 1/w 1.2; 0.6 length of pleon (measured in dorsal view).
Male pleopod I 1/w 3.9; 0.7 length of pleon. Distal corner of limb with slight bulbous process (immature male).
Body Jength 4.3 (holotype), 4.7 (allotype) times tergal width of pereonite 2.
Remarks.—This species is most similar to H. vafer n. sp. These two species differ in the shape of the distal article of antenna I, and the positioning of the pleonal posterolateral processes. The males of the two species differ in the degree of narrowing of pereonites 4 and 5 relative to the female and in the morphology of pleopods I.
Hebefustis par n. sp. Figure 11
Holotype.—WHOI 328, preparatory female, 2.4 mm long, USNM 169396.
Paratype.—WHOI 328, male, 1.8 mm long, USNM 169397.
Other material.—WHOI 156, 21 spec.; WHOI 256, 8 spec., SIO, ZMUC.
Distribution.—Northeast, equatorial, and South Atlantic Ocean, 3459-4435 m.
Etymology.—Latin, equal, a match.
Diagnosis.— Antenna I segment 5 elongate and bulbous, widest distally; length 3.3 (holotype), 3.2 (allotype) times greater than width (1/w). Segment 5 (holotype and allotype) length approximately equal to length of segment 2.
Pereonites 6 and 7 without posterolateral processes. Pereonite 4 1/w 0.5. Width 0.9 (holotype), 0.7 (allotype) times width of pereonite 2. Pereonite 2 with robust seta on anterolateral corner.
Pleon with acute processes (teeth) 0.8 (holotype), 0.9 (allotype) distant from anterior edge. Anterior to teeth, sides of pleon slightly convex, tapering inward in front of teeth. Pleon width between midpoints of concavities formed by teeth 0.7 times width of pleon. Pleon width 0.8 (holotype), 0.9 (allotype) times width of pereonite 2. Pleon 1/w 1.0 (holotype and allotype).
Female operculum length approximately equal to width; 0.66 length of pleon.
Male pleopod I 1/w 4.2; 0.8 times length of pleon. Lateral lobes with oblique ridge.
Body length 3.7 (holotype), 3.0 (allotype) times tergal width of pereonite 2.
Remarks.—This species has a rather broad geographic range. There are subtle differences among individuals of the three stations in the first antennae and in the shape of pereonite 4. However, the range of this variability is not appreciably greater than that within any one population. The paucity of copulatory males at these stations may preclude recognition of specific differences among the popula- tions. Of the species lacking posterolateral projections on pereonites 6 and 7, H. par n. sp. is most similar to H. alleni n. sp. These two differ from the other species of this cluster in having more robust bodies relative to their length. Hebefustis par differs from H. alleni in having a more elongate distal segment of antenna I,
36
Figure 11. Hebefustis par n. sp., WHOI 328. A. preparatory female (holotype), dorsal view; B. prepara- tory female (holotype) right antenna I, lateral view; C. preparatory female (holotype) pleon, ventral view; D. preparatory female right pereopod I, in situ; E. male (paratype), dorsal view; F. male (paratype) left antennae I and II, dorsal view; G. male (paratype) left antenna I, dorsal view; H. male (paratype) pleon, ventral view; I. male (paratype) right pereopod I, in situ.
approximately equal in length to article 2, and in the more anterior placement of the pleonal posterolateral teeth.
The setation of the merus may differ between the right and left first pereopods of the same individual. In Figure 11, the differences in setation of the right first pereopods of the female and male are shown. The setation on the ventral surface of the merus of the left female first pereopod is the same as that on the merus of the right male first pereopod.
37
Figure 12. Hebefustis alleni n. sp., Allen S33. A. preparatory female (holotype), dorsal view; B. prepara- tory female (holotype) left antenna I, dorsal view; C. preparatory female (holotype) left uropod, in situ; D. preparatory female (holotype) right pereopod I, in situ; E. preparatory female (holotype) pleon, ventral view. WHOI 142. F. female, dorsal view; G. female right antenna I; H. female pleon, ventral view; I. female left pereopod I.
Hebefustis alleni n. sp. Figure 12
Holotype.—Allen S33, preparatory female, 1.8 mm long, USNM 169398.
Other material.—WHOI 142, 6 spec., 1 frag.
Distribution.—Bay of Biscay and northeast Atlantic Ocean, 1623-1796 m.
Etymology.— After John Allen.
Diagnosis.—Antenna I segment 5, 2.4 times longer than wide (1/w); 0.6 times length of segment 2.
38
Pereonites 6 and 7 without posterolateral processes. Pereonite 4 1/w 0.5. Sides relatively straight; width 0.9 times width of pereonite 2. Pereonite 2 with robust seta on anterolateral corners.
Pleon with acute processes (teeth) 0.7 removed from anterior edge. Sides anterior to acute processes gently convex. Pleon width between midpoints of concavities formed by teeth 0.8 times width of pleon; length approximately equal to width.
Female opercular length approximately equal to width. Length of pleopod II 0.6 times length of pleon.
Body length 3.4 times tergal width of pereonite 2.
Remarks.—There are subtle differences in the shape of the pleon in specimens taken from the two localities (see Fig. 12E and 12H). Hebefustis alleni n. sp. can be differentiated from other species of the genus, which lack posterolateral projections on pereonites 6 and 7, on the basis of the robust body form, the relatively compact distal article of antenna I and the more posterior placement of the pleonal processes.
Figure 13. Hebefustis cornutus n. sp., WHOI 126. A. preparatory female (holotype), dorsal view; B. pre- paratory female (holotype) left antenna I, dorsal view, C. preparatory female (holotype) left pereopod I; D. preparatory female (holotype) pleon, ventral view; E. male (paratype), dorsal view; F. male (paratype) left antennae I and II, dorsal view; G. male (paratype) right antenna I, lateral view; H. male (paratype) left antenna I, dorsal view; I. immature male (paratype) pleopods I; J. male (paratype) pleon, ventral view.
39
Hebefustis cornutus n. sp. Figure 13
Holotype.—WHOI 126, preparatory female, 2.0 mm long. USNM 169399.
Paratype.—WHOI 126, immature male, 1.5 mm long, USNM 169400; WHOI 126, 5 spec., SIO.
Other material.—WHOI 95, 1 spec.
Distribution.—Northwest Atlantic Ocean, 3753-3608 m.
Etymology.—Latin, horned.
Diagnosis.— Antenna I segment 5 somewhat bulbous; length to width ratio (1/w) 3.1 (holotype), 2.8 (allotype); sides nearly parallel; length 0.8 (holotype and allotype) times length of segment 2.
Pereonites 6 and 7 with acute processes on posterolateral corners. Pereonite 4 1/w 0.6 (holotype), 0.5 (allotype); sides convex, broadest anteriorly. Width 0.8 (holotype and allotype) times width of pereonite 2. Pereonite 2 with robust setae on anterolateral corners.
Pleon with acute processes (teeth) approximately 0.5 (holotype and allotype) way back from anterior edge. Sides of pleon just anterior to teeth parallel. Width of pleon between concavities formed by teeth 0.9 (holotype and allotype) times width of pleon; 1/w 1.2 (holotype and allotype), 0.8 times width of pereonite 2 (holotype and allotype). Male pleon with angular margin posterior to posterolateral teeth.
Female operculum 1/w 1.1; 0.6 times length of pleon (measured in dorsal view).
Male pleopod I 1/w 4.0; 0.6 times length of pleon (measured in dorsal view); limb tapers distally, without lateral oblique ridge.
Body length 3.6 (holotype), 4.0 (allotype) times tergal width of pereonite 2.
Remarks.—Note the double angles of the male pleon, somewhat similar to the pleon of H. primitivus. Hebefustis cornutus belongs to the cluster of species having acute processes on the posterolateral corners of pereonites 6 and 7. Hebefustis cornutus is readily discriminated on the basis of rather anterior placement of the posterolateral spines on the pleon; the pleon is distinctly longer than wide, and pereonite 4 narrow.
Hebefustis hexadentium n. sp. Figure 14
Holotype.—WHOI 247, preparatory female, 2.2 mm long, USNM 169401.
Paratype.—WHOI 247, male, 1.7 mm long, USNM 169402; WHOI 247, 1 brooding female, SIO.
Distribution.— Argentine Basin, South Atlantic Ocean, 5208-5223 m.
Etymology.—hexa, Latin, six; dens, Latin, tooth.
Diagnosis.—Antenna I-segment 5 broadest proximally, tapering distally. Length to width ratio (1/w) 3.1 (holotype), 2.6 (allotype); length 0.6 (holotype), 0.8 (allotype) length of segment 2.
Pereonites 6 and 7 with posterolateral spines on posterior corners. Pereonite 4 1/w 0.5 (holotype and allotype); broader anteriorly; width 1.0 (holotype), 0.8 (allotype) times width of pereonite 2. Pereonite 2 lacks robust seta on anterolateral corner.
Pleon with acute processes (teeth) 0.6 (holotype and allotype) removed from anterior edge. Sides of pleon parallel anterior to teeth. Width of pleon between mid- points of concavities formed by teeth 0.9 (holotype and allotype) times width of pleon. Pleonal width 0.8 (holotype), 0.9 (allotype) times width of pereonite 2. Pleon 1/w 1.05 (holotype and allotype).
Female operculum 1/w 1.1; 0.6 length of pleon.
Male pleopod I 1/w 3.6, 0.7 length of pleon; not flaring distally; without oblique ridge.
40
Figure 14. Hebefustis hexadentium n. sp., WHOI 247. A. preparatory female (holotype), dorsal view; B. preparatory female (holotype) left antenna I, dorsal view; C. preparatory female (holotype) pleon, ventral view; D. brooding female right pereopod I; E. male (paratype), dorsal view; F. male (paratype) right antenna II, dorsal view; G. male (paratype) left antenna I, lateral view; H. male (paratype) left pereopod I, in situ; I. male (paratype) pleon, ventral view.
Body length 3.9 (holotype), 4.2 (allotype) times tergal width of pereonite 2.
Remarks.—The lack of a robust seta on the anterolateral corner of pereonite 2 is unique among the species of this genus.
Hebefustis hexadentium n. sp. is strikingly similar to H. hirsutus (Menzies, 1962b). It differs in lacking a robust seta on the anterolateral corner of pereonite 2, in having a less rounded pleon anterior to the teeth, and in having a uropodal endopod that is somewhat longer relative to its width. Because the holotype of H. hirsutus is lost, the relationships of these two species cannot be explored.
Hebefustis hexadentium differs from the other new species possessing acute
41
Figure 15. Hebefustis dispar n. sp., WHOI 202. A. preparatory female (holotype), dorsal view; B. pre- paratory female (holotype) right antenna I, lateral view; C. brooding female right pereopod I; D. pre- paratory female (holotype) pleon, ventral view; E. male (paratype), dorsal view; F. male (paratype) right antenna I, lateral view; G. male (paratype) pleon, ventral view; H. male (paratype) right pereopod I.
processes on pereonites 6 and 7 in the intermediate placement of the pleonal poster- olateral spines and the relative shortness of the second article of antenna I.
Hebefustis dispar n. sp. Figure 15
Holotype.—WHOI 202, preparatory female, 2.4 mm long, USNM 169403. Paratype.—WHOI 202, male, 1.8 mm long, USNM 169405; WHOI 202, 103
spec. and frag., SIO, ZMUC. Distribution.—Southeast Atlantic Ocean, 1427-1643 m.
42
Etymology.—Latin, unequal, dissimilar.
Diagnosis.— Antenna I segment 5 increases in width distally, length to width ratio (1/w) 2.8 (holotype), 3.0 (allotype); 1.1 (holotype and allotype) times longer than segment 2.
Pereonites 6 and 7 with posterolateral acute processes on posterior corners. Pereonite 4 1/w 0.4 (holotype), 0.5 (allotype); segment broadest posteriorly or with parallel sides; width 0.8 (holotype and allotype) times width of pereonite 2. Pereonite 2 with robust seta on anterolateral corners.
Pleon with acute posterolateral processes (teeth) 0.7 (holotype and allotype) removed from anterior edge. Sides of pleon anterior to teeth converge posteriorly; width of pleon between midpoints of concavities formed by teeth 0.7 (holotype), 0.8 (allotype) times pleonal width. Pleonal width 0.9 (holotype), 1.0 (allotype) times width of pereonite 2. Pleon 1/w 0.84 (holotype), 0.89 (allotype).
Female operculum 1/w approximately 1.0; 0.7 times length of pleon (measured in dorsal view).
Male pleopod I 1/w 4.2, 0.8 length of pleon; somewhat flared distally, with oblique ridge on surface, terminating at lateral lobe.
Body length 3.4 (holotype), 3.9 (allotype) times tergal width of pereonite 2.
Remarks.—This species belongs to that cluster possessing acute processes on the posterolateral margins of pereonites 6 and 7. Hebefustis dispar is readily dis- tinguished by its distinctive first antenna, and the converging sides of the pleon anterior to the teeth. Male pleopods I possess distinctive ridges on the distal surface.
ACKNOWLEDGEMENTS
We thank the heads of the collecting programs who have provided materials to us (see Introduction). T. E. Bowman, National Museum of Natural History, Washington, D.C. and H. S. Feinberg, The American Museum of Natural History, New York City kindly made specimens available for our exami- nation. The manuscript benefitted greatly from the editorial comments and criticisms of W. A. Newman and T. Wolff. This research was supported by grants GA 31344X and DES 74-21506 of the National Science Foundation.
LITERATURE CITED
BirsTEIN, J. A., 1962. Ueber eine neue Art der Gattung Austroniscus Vanhoffen (Crusta- cea, Isopoda, Asellota) aus grossen Tiefen des nord-westlichen Teiles des Stillen Ozeans. Izdanija Posebna Zavoda Za Rib- arstvo NRM, Skopje 3: 33-38.
BIRSTEIN, J. A., 1963a. Deep sea isopod crusta- ceans of the northwestern Pacific Ocean. Institute of Oceanology, USSR Academy of Sciences, Moscow. 214 p.
BIRSTEIN, J. A., 1963b. Isopods (Crustacea, Iso- poda) from the ultraabyssal zone of the Bougainville Trench. Zoologischeskii Zhur- nal 42: 814-834. (In Russian with English summary)
BIRSTEIN, J. A., 1970. New Crustacea Isopoda from the Kurile-Kamchatka Trench area, pp. 308-356. Jn, Fauna of the Kurile- Kamchatka Trench and its environment, V. G. Bogorov (ed.), Vol. 86. Proceedings of the P. P. Shirshov Institute of Oceanology, Academy of Sciences of the USSR, Moscow. (English translation: Israel Program for Scientific Translation, Jerusalem, 1972.)
GURBUNOV, G. P., 1946. Bottom inhabitants of the Siberian shallow water andcentral parts of the North Polar Sea. Trudy drej. Eksled.
Glavs. Ledok. Paroch. ‘‘G. Sedov’’ 1937- 1940, 3: 30-138. (In Russian)
GuURJANOVA, E., 1932. Les Isopodes des mers Arctiques. Tableaux analytiques de la faune de 1'U.R.S.S. Institute of Zoology, Academy of Sciences of the USSR (Leningrad). 181 p. (In Russian)
GuURJANOVA, E., 1933. Die marinen Isopoden der Arktis. Fauna Artica 6: 391-470.
GURJANOVA, E., 1950. K faune ravononogich rakov (Isopoda) Tichogo okeana v. Isopod’ po sboram Kamchatskoi morskoi stanstii Gosudarsevennogo gidrologischskogo in-ta. Akademita nauk SSSR. Zoologischskii insti; tut. Issledovaniia dal ‘nevostochnykh morei SSSR, 2: 281-292.
HANSEN, H. J., 1916. Crustacea Malacostraca, III. V. The order Isopoda. Danish Ingolf- Expedition, Copenhagen. 262 p.
HESSLER, R. R., 1970. The Desmosomatidae (Iso- poda, Asellota) of the Gay Head-Bermuda Transect. Bulletin Scripps Institution of Oceanography 15: 1-185.
HESSLER, R. R. and H. L. SANDERS, 1967. Faunal diversity in the deep sea. Deep-Sea Research 14: 65-78.
HESSLER, R. R. and D. THISTLE, 1975. On the
place of origin of deep-sea isopods. Marine Biology 32: 155-165.
Hopcson, T. V., 1910. Crustacea, IX. Isopoda. National Antarctic Expedition, Natural History 5: 1-77.
Just, J., 1970. Decapoda, Mysidacea, Isopoda and Tanaidacea from Jgrgen Brgnlund Fjord, North Greeland. Meddelelser om Grgnland 184(9): 1-32.
KusSAKIN, O. G., 1973. Peculiarities of the geo- graphical and vertical distribution of marine isopods and the problem of deep-sea fauna origin. Marine Biology 23: 19-34.
MENZIES, R. J., 1962a. The zoogeography, ecol- ogy and systematics of the Chilean marine isopods. Report of the Lund University Chile Expedition, 1948-1949, 42: 1-162.
MENZIES, R. J., 1962b. The isopods of abyssal depths in the Atlantic Ocean. Vema Research Series 1: 79-206. Columbia Univer- sity Press, New York.
Menzies, R. J. and R. Y. GEORGE, 1972. Isopod Crustacea of the Peru-Chile Trench. Anton Bruun Reports 9: 1-124.
MENZIES, R. J., R. Y. GEORGE and G. T. ROwE, 1973. Abyssal environment and ecology of the world oceans. Wiley-Interscience, New York. 488 p.
MENZIES, R. J. and J. PETTIT, 1956. A new genus and species of marine asellote isopod, Cae- cianiropsis psammophila, from California. Proceedings United States National Museum 106: 441-446.
NORDENSTAM, A., 1933. Marine Isopoda of the families Serolidae, Idotheidae, Pseudido- theidae, Arcturidae, Parasellidae, and Ste- netriidae mainly from the South Atlantic. Further zoological results of the Swedish
43
Antarctic Expedition, 1901-1903 (Sixten Bock, ed.), 3: 1-284.
RICHARDSON, H. E., 1908. Some new Isopoda of the Superfamily Aselloidea from the Atlan- tic Coast of North America. Proceedings United States National Museum 35: 71-86.
SANDERS, H. L. and R. R. HESSLER, 1969. Ecology of the deep-sea benthos. Science 163: 1419-1424.
SANDERS, H. L., R. R. HESSLER and G. R. Hampson, 1965. An introduction to the study of deep-sea benthic faunal assem- blages along the Gay Head-Bermuda Transect. Deep-Sea Research 12: 845-867.
Sars, G. O., 1870. Nye Dybvandscrustaceer fra Lofoten. Forhandlinger Videnskabers Sel- skab Kristiana, 1869: 145-286.
Sars, G. O., 1885. Crustacea, I. Norwegian North Atlantic Expedition, Zoology (1876-1878) 1: 1-276.
Sars, G. O., 1897. On some additional Crustacea from the Caspian Sea. Annals of the Museum of Zoology, Imperial Academy of Science, St. Petersbourg, 1897: 273-305.
Sars, G. O., 1899. An account of the Crustacea of Norway, II. lsopoda. Bergen Museum. 270 p.
ScHuLTz, G. A., 1966. Submarine canyons of southern California. Part 4, Systematics: Isopoda. Allan Hancock Pacific Expedi- tions 27: 1-56.
VANHOFFEN, E., 1914. Die Isopoden der deutschen Stdpolarexpedition 1901-1903. Deutschen Siidpolar Expedition, 15 (Zool- ogy) 7: 447-598. (G. Reimer, Berlin)
Wo FF, T., 1962. The systematics and biology of bathyal and abyssal Isopoda Asellota. Galathea Reports 6: 1-320.
Scripps Institution of Oceanography, A-002, La Jolla, CA 92098
7 - has am ie re
~ a
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 3 pp. 45-52 25 June 1979
First records of Risso’s dolphin (Grampus griseus) from the Gulf of California with detailed
notes on a mass stranding
Stephen Leatherwood, Carl L. Hubbs, and Matilda Fisher
Abstract. Grampus griseus has been reported in the northeastern Pacific (near the coast) from southern British Columbia, Canada, to Acapulco, México, and near 2 oceanic islands, Isla de Gua- dalupe, off Baja California, México, and Clipperton Island, west of Costa Rica. On the basis of 2 sightings from an aircraft and of observations in detail on a mass stranding, penetration into the Gulf of California is herein recorded.
Resumen. Grampus griseus se extiende en la region nordeste del Pacifico desde cerca de las costas meridonales de la Columbia Britanica (Canada) hasta Acapulco (México) y en las inmediaciones de 2 islas oceanicas, Guadalupe (frente a Baja California) y Clipperton (al oeste de Costa Rica). Se incluye informacion sobre la penetracion de esta especie en el Golfo de California, al considerar 2 observaciones desde un avion y los datos detallados obtenidos al vararse y morir cinco individuos en las costas del Golfo.
INTRODUCTION
The wide-ranging, nearly cosmopolitan delphinid Grampus griseus (Cuvier), often called ‘‘Risso’s dolphin’ (Fig. 1), has been reliably reported in the northeastern Pacific Ocean: inshore, from southern British Columbia (Guiguet and Pike 1965) southward to Acapulco, México, and offshore, not only of the mainland coast, but also near oceanic islands, including Isla de Guadalupe, off the Mexican state of Baja California (Hubbs 1961:145), and from Clipperton Island, west of Costa Rica (Leatherwood et al. 1972:92). These records, and many others, from the northeastern Pacific, are being documented by Stephen Leatherwood and colleagues.
This paper presents observations that document the penetration of Grampus gris- eus into the Gulf of California, on the basis of 2 well-separated sightings from an airplane on a marine-mammal survey, and of detailed observations along the north- western shore of the Gulf, by Matilda Fisher and family, of a mass stranding of 5 individuals, all of which died overnight. Some plausible causes of such lethal strandings are discussed.
Because this species was not seen by 2 of us (Leatherwood and Hubbs), on nu- merous research trips around the Gulf, by ship, automobile, and airplane, we believe that Risso’s dolphin is not common anywhere in the Gulf of California.
AERIAL OBSERVATIONS
During an aerial survey of marine mammals in the tropical eastern Pacific Ocean, National Marine Fisheries Service observers Eric G. Barham, William E. Evans, and James M. Coe encountered herds of Grampus griseus at 2 well-separated locations in the Gulf of California, México (Fig. 2). At 0958 h, 13 February 1974, they observed a herd estimated to contain 50 + 10 individuals at ~ 24°52’N, 108°58’W, in the
46
Fic. 1. Grampus griseus, | of several collected on northeastern shore of Florida and exhibited in Marine- land of Florida.
47
A Stranding @ Sightings
Pacific Ocean
115°W 110° W
Fic. 2. Location of records for Grampus griseus in the Gulf of California.
southern and eastern part of the Gulf, some distance west of Isla Altamura, Sinaloa. At 1216 h on the same day they saw 2 more individuals of the species much farther north, at ~ 28°21'N, 112°30'W, close to the northern and western shore of the Gulf, southwest of Isla San Lorenzo, and off the far-southern part of the State of Baja California (which occupies the northern half of the peninsula of the same name). Each of these locations is close to, if not partly within, one of the deep basins that occupy much of the southern two thirds of the Gulf (Shepard 1950, Rusnak et al. 1964). Because this delphinid seems to be largely an offshore species wherever it occurs, it may well be assumed that in the Gulf it occurs chiefly in the deeper areas, where the water is relatively clear.
The stranding here recounted, however, lies in the transitional area approaching the northern part of the Gulf, where the water is relatively shallow, and often rendered more or less turbid by the upwelling of deep deposits of varved sediment that have stemmed from past discharges of the sediment-rich Colorado River.
48
THE LETHAL MASs STRANDING
On 18 June 1973, the vacationing family of Ernest G. Fisher, of Brea, California, while camping on the northwestern shores of the Gulf of California, encountered the stranding of 5 cetaceans that were later identified, from their photographs (Fig. 3), as Risso’s dolphins. The Fisher camp was at Punta Bufeo, ‘“‘about 5 miles’? [~ 8 km] north of the establishment of *‘Papa Fernandez,’’ on Bahia San Luis Gonzaga, in the state of Baja California (Fig. 2). At ~ 1700 h they watched several large dolphins seemingly chasing a large school of fish, thought to be mullet, and apparently taking some at the surface, in the presence of numerous gulls. The dolphins were relatively close to the beach, usually within 100 m. At times they approached the shoreline, where a broad shallow shelf was being created by the receding tide (Fig. 3a).
At ~ 1730 h the dolphins ceased their apparent feeding activity and headed toward the beach. One of them (in the foreground in Fig. 3b) suddenly outstripped the other 4 and continued alone up the gradually sloping beach, at first separately, until it was in no more than ‘‘one foot”’ [~ 0.3 m] of water (not enough to cover it). Here, for ~ 10 minutes, it began rooting in the sand. By then breathing seemed to have become labored, and the animal appeared to be unable to maintain an upright position. Not long after this individual had moved shoreward, the 4 other dolphins slowly proceeded into shallow water, where they remained with the first that stranded and kept nudging at it; at times they gave the impression of trying to force it back toward deeper water (Fig. 3c). For some time, the 4 remained near the obviously incapacitated individual, even when members of the observing party entered the rapidly shoaling water and touched them. To the observers, the breathing of the other animals seemed to remain more normal than that of the first to strand, and their actions seemed to be more coordinated. They appeared to avoid complete stranding, even when they ventured into water < ‘‘one foot’’ [~ 0.3 m] deep. They extricated themselves from the beach and negotiated the tidal change. The observers got the impression that the 4 may have merely followed the ‘“‘leader’’ to the point of death.
By ~ 1800 h the dolphin that first approached the shore had definitely stranded. As the tide continued to ebb, during the large tidal movements characteristic of the upper Gulf, the 4 still-mobile animals gradually moved farther from the beach, but continued to stay close inshore. By midnight, the first grampus that stranded had died, and was being carried up the beach by the incoming tide. The 4 pod-mates were still in attendance, remaining within ‘‘about 100 feet’? [~ 30 m], swimming back and forth along the beach. At ~ 0200 h the following morning (19 June), the situation had not changed, except that the first animal to strand and die was being tossed about in the surfline of the still-incoming tide, while the other 4 still stayed within *‘100 feet’’ [~ 30 mJ], seemingly patrolling.
At dawn, ~ 0530 h, the dead animal was high and dry (Fig. 3d). Its length was estimated at the site to be ‘‘12—13 feet’’ [nearly 4 m] and its weight to be ‘*600 Ibs”’ [~ 270 kg]. No major recent external injuries were apparent, though the body was covered by numerous healed scars (as is characteristic of the species). Subsequent examination of the photographs showed that it was a female. At 0600 hr the other 4 pod-mates were found to be stranded about **300 ft’’ [~ 100 m] southward, but were still alive. By 0800 h they too had perished. All 4 were estimated to be of about the same size, about ‘‘12 ft’’ [4 m] and to weigh ‘‘500 to 600 Ibs’’ [~ 227-272 kg]. They also were heavily scarred, but none showed any obvious recent external injury. Examina- tion of the photographs (Fig. 3e) showed that at least 3 were females: at least 4 of the 5 animals were of that sex.
Although all of the dolphins were of similar size, they varied considerably in coloration. One was nearly white all over; the others ranged from dark gray to light gray (another characteristic of the species), with white areas of varying size on the belly. All 5S carcasses were towed offshore and released in the Gulf.
These detailed observations of the stranding of a pod of Grampus griseus appar- ently constitute the first known sighting of the genus and species in the Gulf of Cali-
49
Fic. 3. Sequential views of the reported stranding of Grampus griseus. a. The 5S Grampus dolphins are in the shallows where they had been feeding on mullet (~1700 h, 18 June 1973). b. The animals approaching the shallows (~1730 h). c. The first animal in the process of stranding (~1740 h). The other 4 continue to remain close by, despite the rapidly ebbing tide, at times nudging the “‘distressed’’ one. d. The following morning (~0530 h, 19 June 1973) the first one to strand is now high and dry. e. The remaining 4 stranded animals alive ~10 m farther down the beach (~0600 h, 19 June 1973).
fornia. The observed details of this stranding follow in various respects the sequences described for some other almost continuously watched cetacean strandings, including one involving ~ 20 pilot whales (Globicephala sp.) recounted by Hubbs (in Norris 1966:605). In a rather major aspect, however, this Grampus mass stranding seems to
50
differ, in that just before starting to strand, the 5 individuals appeared to be feeding actively, whereas it has generally been thought that stranded cetaceans have little or no recently ingested food in their stomachs. One noted exception to this generalization involved an adult female pilot whale found on 20 August 1952 freshly stranded at Encinitas, San Diego County, California, with flesh so flaccid that a depression formed by slight pressure on the surface remained, although the stomach and even the throat were strangely crammed with freshly ingested giant kelp, Macrocystis, calling to mind the propensity of sick dogs to devour grass.
The behavior of a single member of the grampus group here reported suddenly changed, its respiration seemed labored and its equilibrium appeared unstable. For some time, the 4 others appeared to function normally, while staying close to the one first stranded.
Why cetaceans, such as those comprising this pod of Grampus, at times rather suddenly strand and then die, as individuals or in groups of varying size, for no readily perceptible reason, has long been a topic of discussion, probably largely because thor- ough postmortem studies are often lacking. Some postmorten examinations have re- vealed that at least some strandings result from sickness or injury. Alternatively, some mass strandings seem to have involved apparently healthy and uninjured animals. Those stranded, individually or in groups, frequently seem to make little or no effort to head back seaward, often even resisting efforts of sympathetic persons to lead them to safety.
The observations recounted here, although contributing some data on events in a cetacean stranding, seem to have no critical bearing on the cause or causes of the lethal phenomenon. Theories regarding causes of cetacean strandings have been many and diverse. A recent summary (Leatherwood et al. 1976) states:
Strandings of lone individuals usually involve an animal which is sick or injured. Mass strandings, involving from several to several hundred individuals, appear to be far more complex and may result from herd-wide disease conditions, from fear reactions, or from failure of the echolocation system due to physiological problems or environmental conditions which combine to reduce its effectiveness, to mention only a few.
Reysenbach de Haan (1957), Fraser (in Norris 1966:602), Caldwell and Caldwell (1971), and Ridgway and Dailey (1972), among others, have discussed the probable role of parasitism in strandings of cetaceans. James G. Mead (personal communication) found that all members of a herd of short-finned pilot whales (Globicephala macro- rhynchus) that stranded in North Carolina in 1974 were heavily infested by parasites in the ear canals, implicating possible mass infection in whole-herd strandings. Inci- dence of such infestation of the middle ear was found to be relatively low in samples of presumably healthy spotted and spinner dolphins (Stenella spp.) incidentally cap- tured in tuna seines, but changes in incidence with age suggest that the parasite or parasites involved may be a factor in natural mortality (Dailey and Perrin 1973). It 1S hoped that such evidence of the association of parasitism with stranding will be further tested, along with additional determination of such parasitism in nonstranded ceta- ceans.
ACKNOWLEDGMENTS The authors thank Eric G. Barham, James M. Coe, and William E. Evans for providing the sight records from the Gulf of California, and William E. Evans, James G. Mead, Kenneth S. Norris, William F. Perrin, Sam H. Ridgway, and Forrest G.
Wood for helpfully reviewing the manuscript. David K. Caldwell kindly provided the photograph reproduced as Fig. 1.
LITERATURE CITED
Caldwell, M. C., and D. K. Caldwell, 1971. Sen- Dailey, M. D., and W. F. Perrin, 1973. Helminth ses and communication. Pages 466-496 in S. parasites of porpoises of the genus Srenella in H. Ridgway, editor. Mammals of the sea: bi- the eastern tropical Pacific, with descriptions ology and medicine. Charles Thomas Publish- of two new species: Mastigonema stenellae
er. gen. et sp. n. (Nematoda: Spiruroidea) and
Zalophotrema pacificum sp. n. (Trematoda: Digenea). Fisheries Bulletin 71:455—471. Guiguet, C. J., and G. C. Pike, 1965. First spec- imen of the gray Grampus or Risso’s dolphin, Grampus griseus (Cuvier) from British Co-
lumbia. The Murrelet 46(1):16.
Hubbs, C. L., 1961. The marine vertebrates of the outer coast. Jn The biogeography of Baja Cal- ifornia and adjacent seas, Part II. Systematic Zoology 9 (3 & 4):134—147.
Leatherwood, J. S., D. K. Caldwell, and H. E. Winn, 1976. The whales, dolphins and por- poises of the western North Atlantic/A guide to their identification. NOAA Tech. Rep. NMFS CIRC-396. 176 pp.
Leatherwood, S., W. E. Evans, and D. W. Rice, 1972. The whales, dolphins, and porpoises of the eastern North Pacific/A guide to their iden- tification in the water. Naval Undersea Center Technical Paper 282, Naval Undersea Re- search and Development Center, San Diego, California 92152 USA, 175 pp.
Norris, K. S., editor. 1966. Whales, dolphins and
51
porpoises. University of California Press, Berkeley and Los Angeles, California, USA. 789 pp.
Reysenbach de Haan, F. W., 1957. Hearing in whales. Acta Oto-Laryngologica, Supplement 134, 114 pp.
Ridgway, S. H., and M. D. Dailey, 1972. Cerebral and cerebellar involvement of trematode par- asites in dolphins and their possible role in stranding. Journal of Wildlife Diseases 8:33- 43,
Rusnak, G. A., R. L. Fisher, and F. P. Shepard, 1964. Bathymetry and faults of Gulf of Cali- fornia. Jn Tjeerd H. van Andel and George G. Shor, Jr., editors. A symposium—Marine ge- ology of the Gulf of California. American As- sociation of Petroleum Geologists Memoir 3:59-75.
Shepard, Francis P., 1950 Submarine geology of the Gulf of California. Jn Part III, Submarine topography of the Gulf of California, Geolog- ical Society of America, Memoir 43:vii + 30 pp.
Leatherwood: Hubbs Sea World Research Institute, San Diego, California 92109 USA. Hubbs: Scripps Institution of Oceanography, La Jolla, California 92093 USA. Fisher: 621 South Maple Avenue, Brea, California 92621 USA.
: it. oe 7 2 A rey) ind Same § di? *. 1) ' ities a Kine 7 Agia Sei ob hs FL MMis 18 eg THitipis gti ie hie y\ ah we ay Res *vee TAG til here (aT ieee Sigel) 6 LA f jiu eink 0 8 fete 19 Peds | = > & ie | a Sp Yep G0 ' oh a peeret 02) Gt Ba ies i I eee Ba th a) ihe Ke _ Z ets: | Ta) oe -. a : P Se a ay Len nh ene afl t7 1, Hil hteesy 60 Leia | fe" od Sheed a ete $ oe b Vig |p ap! De @ant=~ Cire» Fy A , aL ’ metres (98) fi pre &PG; banat viv ae Fh, haces 1? Badger! wo @ Pe ty : ihee a 4" VLE tee Pe a) <iee hic ; sien Oh Sete il eu ( itiaivne » ae Cil an < PI Seiitar: |) reir yy msiP. 38 4 Ge, t Te ee ¢ Ag tis jee in —- penile? 1 ee ; sy | ibd 9 Snmaee Shin id eo ae > 5 27 i) Via eto ih a | sesign Un’ . 7 mn) wr Wes wiz . eT oe Hey - jo eae ee 14. - & 4 , int: eo oh iL) A eats Te Se Fey i Inu Mote. a = dee i, i eT Re Beoenh, viet rte. ag r iP Tua tri Maes
f } Print pee Se | vive piuve Masoestr pcan Peat nee Rete ak Siege ieui! i 9 herqurel Sr epee an A nd? lrines @) we as © » PLING oily, Pea:
, hg dbs, ii
’ A ae ii Nye )) ae an) earns 4 7% a ag
it 54 et Sad 14en Yn" | spe FENN kes pirernety, ae Poet ra oamte art hpmaarty
ere ta Val a ey ts
Wierd fh, - Nupo be a VG iy « 6i%, bat So ry ' epi
iiive, wgeest | Gp: ¢ q — {
~
ed
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
JOANELLIA LUNDI SP. NOV. (CRUSTACEA: MALACOSTRACA) FROM THE MISSISSIPPIAN HEATH SHALE OF CENTRAL MONTANA
JOAN M. SCHRAM AND FREDERICK R. SCHRAM
Department of Paleontology, Natural History Museum, San Diego, California 92112 USA
Abstract. Joanellia lundi is described from the Heath Shale of Montana. The material rep- resents a poorly sclerotized aenigmacarid associated with the syncaridan Squillites spinosus. It is the first occurrence of the genus Joanellia in North America.
Schram and Schram (1974) redescribed the syncarid malacostracan, Squillites spi- nosus Scott, 1938, from a black paper shale near the top of the Heath Shale, based on material found by Dr. Richard Lund of Adelphi University. Associated with Squillites in the Heath is a biota of leaf fragments encrusted with Spirorbis, conchostracan crustaceans, an aenigmacarid aeschronectidan (Malacostraca: Hoplocarida), and ver- tebrates (xenacanth sharks, acanthodian, and paleoniscoids). The associated fauna and stratigraphy of the Heath Shale are related in detail in Schram and Schram (1974).
The aenigmacarid aeschronectidan of the Heath Shale is described here. The material is plentiful but poorly preserved and comes from two localities in Fergus County, Montana: most specimens from sec. 28, T. 14 N, R 20 E, 1.2 km [=2 miles] south and 3.7 km [=6 miles] east of Heath; and some from T. 14.N, R. 19 E, 1.4 km [=2'4 miles] south of Heath. The material is deposited in the Field Museum of Natural History, Chicago (numbers prefixed PE) and the Carnegie Museum of Natural History, Pittsburg (numbers prefixed CM).
DISCUSSION
The association of the aenigmacarid, Joanellia lundi, with the syncaridan, Squil- lites spinosus, is noteworthy. The associated faunas of the Heath Shale and general regional lithology indicate the Heath represents a lagoonal setting (R. D. Norby, per- sonal communication). This is another instance in the Paleozoic when an aenigma- carid—syncaridan association in a lagoonal setting is recorded. The other is in the Upper Pennsylvanian, Madera Formation, of New Mexico (Schram and Schram, 1979) where Aenigmacaris minima is found with the syncarid Uronectes kinniensis. Thus, there seems to be a distinctive Late Paleozoic lagoonal fauna of crustaceans akin to what is seen in nearshore marine and coal measure chronofaunas (Schram, in press).
This is also the first occurrence of the genus Joanellia in North America. It was previously only known from the Lower Viséan of Britain (Schram, 1979). Interestingly, the earlier occurrence is in the entirely different faunal setting of a nearshore marine habitat.
SAN DIEGO SOC. NAT. HIST., TRANS. 19(4):53-56, 25 June 1979
Fic. |. Joanellia lundi sp. nov. (A) PE 18383, holotype. (B) PE 18382, anterior abdomen with stenopodous pleopods. (C) PE 18384, anterior of abdomen with pleomere pleura. (D) PE 18373, preserved remnants of pleopod muscles. a—antenna, ab—abdominal segments, p—pleopods, pl—pleomere pleura, pm—pleopod muscles, PE—specimens deposited at the Field Museum of Natural History, Chicago. Scales = | mm.
SYSTEMATICS
Class MALACOSTRACA Latreille 1806 Subclass HOPLOCARIDA Calman 1904 Order AESCHRONECTIDA Schram 1969 Family AENIGMACARIDIDAE Schram and Horner 1978 Genus JOANELLIA Schram 1979
Diagnosis.—Small aenigmacarid. Carapace subtrapezoidal in lateral outline. Sec- ond pleomere longer than any of the other first 5 pleomeres. Uropods terminal on 6th pleomere and directed posteriorly (probably flap-like).
Range.—Dinantian (Viséan) to Middle Namurian (Upper Mississippian).
Remarks.—The genus Joanellia was described by Schram (1979) based on Viséan material from Scotland and northern England. Schram and Horner (1978) suggested allying Joanellia with the genus Aenigmacaris. This assignment was based on both genera having very elongate and poorly sclerotized tailfans, and stenopodous pleopods.
JOANELLIA LUNDI sp. nov. Figs. | and 2, Table 1
Diagnosis.—Carapace subtrapezoidal with short rounded branchiostegal lobes. Cuticle poorly sclerotized. Abdominal pleurites | through 4 with posterior extension and triangular ventral margins.
ln nn
-
- as “a
Fic. 2. Joanellia lundi sp. nov. from the Heath Shale, Upper Mississippian, Montana (dots indicate location of mandible and pleopod muscles). (B) Joanellia elegans (Peach) 1908, Dinantian, Lower Carboniferous, Great Britain.
Holotype.—PE 18383 (Fig. la).
Type locality.—As described in the introduction (collected specimens not sepa- rated as to locality).
Derivation of name.—Named in honor of Dr. Richard Lund, the collector of the material, who over the years has generously made this and other Paleozoic crustacean material available to us for study.
Description.—The entire cuticle of the animal is poorly sclerotized. The carapace has a blunt anterior end with a faint optic notch (PE 18383, Fig. la, CM 33893). The posterior carapace margin is gently curved or bowed anteriad and the branchiostegal lobe is rounded (PE 18384, CM 33898). Only the proximal segments of antennae have been preserved, and several specimens (e.g., PE 18383, Fig. la, PE 18384, CM 33893) reveal the proximal segment was moderate in size and the next most distal segments were of longer but. undetermined length. The mandible (PE 18383, 18384) is relatively large but apparently not highly sclerotized nor mineralized.
The first 4 pleomeres are all similar, except for the 2nd being larger than any of the others (PE 18384, Fig. 1c). The first 4 abdominal segments have triangular ventral margins and a posteriorly directed extension on the pleuron (PE 18317, 18384, Fig. 1c). The Sth pleomere pleura is broadly rounded (PE 18375). Pleomeres 1 through 5 have stenopodous pleopods (PE 18323, 18375, 18382, Fig. Ib), with only the proximal short segments, and part of the long, next most distal segment being preserved.
TABLE 1. Measurements (in millimetres) for some specimens of Joanellia lundi sp. nov. * denotes the holotype.
Abdominal length
Specimen Carapace length (pleomeres 1-6) PE 18317 Boi es
PE 18373 7.3
PE 18380 11.0
PE 18382 9.4
PE 18383* 4.1 7.4
PE 18384 3.2
CM 33893 7.8
These 5 pleopods were also equipped with a well-developed musculature (PE 18308, 18309a, 18371, 18373, Fig. 1d, 18380, 18383) which took origin on the sides of the abdominal segments. The 6th pleomere is very long (PE 18380). The uropods are apparently flap-like, situated terminally, and directed markedly posteriad (PE 18314, 18383), but further details of their exact form are obscure. Nothing can be discerned concerning the telson.
A partial reconstruction is presented in Fig. 2a.
Remarks.—Because the cuticle was so poorly sclerotized the specimens of Jo- anellia lundi are poorly preserved. As a result really pertinent descriptive features of the antennae, thoracopods, and tailfan are lacking.
Several differences of Joanellia lundi with Joanellia elegans (Fig. 2b) of the Scot- tish Viséan can be delineated. Joanellia elegans has a sharp posterior extension to the branchiostegite lobe of the carapace, no marked posterior extensions on the abdominal pleura, only pleomere pleura | and 2 with triangular ventral margins, and pleomere pleura 3 through 5 broadly rounded.
Some representative measures of Joanellia lundi are given in Table 1.
ACKNOWLEDGMENTS
The authors thank Dr. Richard Lund, Adelphi University, for generously allowing us to study the material, and Dr. Rodney Norby, Illinois State Geological Survey, for helpful discussions concerning the Heath Shale. Drs. Richard Lund and Niles El- dredge, American Museum of Natural History read the manuscript and offered con- structive comments.
LITERATURE CITED
Schram, F. R. 1979. British Carboniferous Malacostraca. Fieldiana: Geology 40:1-129.
. In press. The Mazon Creek biotas in the context of a Carboniferous faunal continuum. Jn M. H.
Nitecki, editor. Mazon Creek Fossils. Academic Press, New York.
, and J. Horner. 1978. Crustacea of the Mississippian Bear Gulch Limestone of Central Montana. Journal of Paleontology 58:394—406.
Schram, F. R., and J. M. Schram. 1979. Some shrimp of the Madera Formation (Pennsylvanian), Manzanita Mountains, New Mexico. Journal of Paleontology 53:169-174.
Schram, J. M., and F. R. Schram. 1974. Squillites spinosus Scott 1938 (Syncarida: Malacostraca) from the Mississippian Heath Shale of central Montana. Journal of Paleontology 48:95—104.
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
THE GENUS ARCHAEOCARIS, AND A GENERAL REVIEW OF THE PALAEOSTOMATOPODA (HOPLOCARIDA: MALACOSTRACA)
FREDERICK R. SCHRAM Natural History Museum. P.O. Box 1390, San Diego, Calfornia 92112 USA
Abstract. Newly discovered material of Archaeocaris graffhami Brooks, 1962, allows a more complete description and reconstruction of that animal. Reexamination of all specimens of Archaeocaris results in some modifications in the reconstruction of Archaeocaris vermiformis Meek, 1872, as well. All Paleozoic palaeostomatopod species are reviewed.
INTRODUCTION
Dr. Charles Sandburg of the United States Geological Survey in Denver, Colorado, referred some crustacean fossils to me for identification which proved to be Archaeo- caris graffhami Brooks, 1962. The specimens were collected from the upper Pilot Shale at Bactrian Mountain in the Pahranagat Range, Nevada, and effectively extend the stratigraphic range of this species from the Upper Mississippian, Chesteran, back into the Lower Mississippian, Kinderhookian.
This new material and my study of the British palaeostomatopods prompted a reexamination of all specimens of Archaeocaris. A general summary review of the entire order is presented, with a clarification of the relationships of Archaeocaris to the rest of the Palaeostomatopods.
SYSTEMATIC PALEONTOLOGY
Phylum Crustacea, Pennant, 1777 Class Malacostraca, Latreille, 1806 Subclass Hoplocarida, Calman, 1904
Order Palaeostomatopoda, Brooks, 1962 Family Perimecturidae, Peach, 1908 Genus Archaeocaris, Meek, 1872
Diagnosis.—Carapace smooth with posterodorsal margin deeply excavated to ex- pose dorsum of posterior thoracomeres; mandible well sclerotized; uropods lobate; telson ovoid: body cross section circular to oval.
Archaeocaris graffhami Brooks 1962. (Figs. 1-3, 4b, 5a) Brooks 1962, p. 214, Pls. 8 and 47; Schram 1969a, p. 217, Table 1.
Diagnosis. —Body moderate to large; weak development of mandible in relation to overall body size; abdominal pleura simple and undecorated; carapace thin and poorly sclerotized.
Remarks.—The holotype (part, Museum of Comparative Zoology at Harvard, 5849, and counterpart, University of Oklahoma, 4411) is poorly preserved (Fig. 5a).
SAN DIEGO SOC. NAT. HIST., TRANS. 19(5):57—66, 25 June 1979
ne rs 8 a
Fic. 1. Archaeocaris graffhami Brooks, 1962; USNM 220967; scale 1 cm.
Most of the tail is missing and there is no carapace. Indeed, as Brooks (1962) pointed out, only the ratio of the width of the mandible to body length, .023 (0.8 mm:35 mm) allowed these specimens to be distinguished from Archaeocaris vermiformis.
Additional material.—The new material from Bactrian Mountain consists of 3 specimens of more or less complete animals. USNM 220967 (Fig. 1), the largest and best preserved specimen, has a mandible width of 0.7 mm and an approximate body length of 41 mm, i.e., ratio of .017, somewhat smaller than for the types of A. graffhami. The body is generally poorly sclerotized, but the carapace is especially so, as seen on USNM 220967 and 220968 (Fig. 2). The tail fan, parts of which are seen on all 3 specimens, appears to consist of an ovoid telson and large lobate uropods, but again, unfortunately the preservation leaves something to be desired. USNM 220969 (Fig. 3) has pleopods preserved, and USNM 220967 and 220968 bear traces of cephalic and thoracic appendages, though little can be definitely determined for any of these except that the anterior thoracopods were subchelate. The deep excavation of the dorsal posterior margin of the carapace is evident on USNM 220967. Although the holotype counterparts are so poorly preserved that comparison with the Nevada spec- imens is difficult, the trapezoidal form and relative size of the mandible, the rounded shape of the abdominal pleurites, and the subchelate appendages seem to relate the entire group of specimens.
The associated fauna at Bactrian Mountain (Sandberg and Poole 1970) is an open marine, relatively deep water fauna of phosphatic brachiopods, Chonetes, sponge spic- ules, and ostracodes. Elias and Branson (1959) report a marine fauna in the Delaware Creek member of the Caney Shale in Oklahoma with the holotype of A. graffhami, including Linoproductus, the clam Caneyella, a snail Macrocheilus, several cephalo- pods, and abundant conodonts. Such a deep water, open marine association is unusual for Late Paleozoic malacostracans, which are more typically found in near-shoreline situations of shallow marine or brackish-freshwater habitats.
The range of A. graffhami is extended by inclusion of the material from Nevada. The lower and middle units of the Pilot Shale are dated on the basis of conodonts as
Fic. 2.. Archaeocaris graffhami Brooks, 1962; USNM 220968; scale | cm.
latest Devonian; the upper Pilot Shale, which contains the shrimp, is lowermost Kin- derhookian in age. The holotype comes from the Caney Shale, uppermost Meremecian or lowermost Chesteran in Pontotoc County, Oklahoma, USA.
Archaeocaris vermiformis Meek, 1872 (Figs. 4a, 5b, 5c)
Meek 1872, p. 335; 1875, p. 321, Pl. 18, Fig. 7; Ortmann 1897, p. 283; Van Straelen 1931, p. 71; Brooks 1962, p. 211, Pls. 8, 45, and 46; 1969, vol. R, p. R535, Fig. 341; Schram 1969a, p. 217, Table 1.
Diagnosis. —Body small; cuticle well sclerotized; relatively strong development of the mandible in relation to overall body size; abdominal pleura sculptured and marked with furrows.
Remarks.—The holotype and paratype series in the National Museum are not as well preserved as the series of specimens at Princeton University (Fig. Sb DC) 597 d/l to 1597 d/14. The treatment of Brooks (1962) remains substantially unchanged by me except for a few points resulting from preparation of the Princeton material.
¥ : * oe Be : itn a 2 ‘ 2. % aa : “ ” paca e >» _ s f * ii é . = # ma fh 2 “ ol OS : oe we Ede Pak %
Fic. 3. Archaeocaris graffhami Brooks, 1962; USNM 220969; scale 1 cm. p = pleopods, t = telson.
60
Fic. 4. Reconstructions of the species of Archaeocaris, scale 1 cm. (a) Archaeocaris vermiformis Meek, 1872. (b) Archaeocaris graffhami Brooks, 1962.
Additional material.—The counterpart of 1597 d/1 to that illustrated in Brooks (1962, Pl. 46, Fig. 2) shows more clearly that the carapace extended along the midline to about the 6th thoracomere and the lateral wings of the carapace extended posteriad to cover the pleurae of the last 3 thoracomeres, thus leaving the 3 posteriormost tho- racomeres exposed dorsally. This arrangement of the carapace is also observable on 1597 d/7. In addition, 1597 d/1 also clearly preserved a series of large spines on the propodus segments of the anterior thoracic appendages opposed to the subchelate dactylus, thus forming a rather formidable battery of claws. 1597 d/2 and d/8 seem to indicate that the coxa of the anterior thoracomeres is short and that there is a mod- erately well developed precoxa proximal to the body. The telson and tail fan are still not well known. The uropods are visible as broad lobes on 1597 d/12, and to a lesser extent on d/4. The telson is smooth and undecorated, and has an oval shape, somewhat more pointed at the distal end (1597, d/4, d/12, d/13, d/14). There is no indication that the telson is developed terminally as a spike, as in Perimecturus and Bairdops, though there is some indication of terminally located, small caudal furca (1597 d/13).
Meek (1875) described A. vermiformis from the Waverly Group, near Danville, Kentucky in association with the phyllocarid, Ceratiocaris. The Waverly fauna 1S generally considered to be marine because the fauna contains such genera as Fenes- trella, Lingula, Orbiculoidea, Productus, Spirifer, Aviculopecten, Palaeoneilo, Schizo- dus, Platyceras, and Conularia, among others. The Princeton material comes from west of Junction City, Boyle County, Kentucky, a site which also yielded a specimen attributed to Palaeopalaemon newberryi.
Genus: Bairdops Schram, 1979
Diagnosis.—Circular or oval in body cross section; carapace rectangular in lateral outline, no dorsally exposed posterior thoracomeres: telson base rectangular with prominent posterior spike. Uropods blade-like.
Remarks.—Two species of Bairdops are recognized: the Viséan Bairdops elegans (Peach) 1908 from the Calciferous Sandstone Series of Scotland, and the Namurian Bairdops beargulchensis Schram and Horner, 1978, from the Bear Gulch Limestone in the uppermost Mississippian of Montana, USA. The principal differences between the 2 species are these. The telson spike in B. elegans is more than half the length of the telson base. The uropodal protopod in B. elegans has only a slight middorsal
61
Fic. 5. (a) Archaeocaris graffhami Brooks, 1962: holotype MCZ 5849. (b) Archaeocaris vermiformis Meek, 1872; PU 1597 d/1 displaying the carapace and subchelate thoracopods. (c) Archaeocaris vermiformis Meek, 1872; PU 1597 d/3 displaying the abdominal pleurites.
posterior spike on the protopod. The uropodal exopod in B. elegans is a simple blade with no setae, while in B. beargulchensis it is laterally serrate and medially setose. The uropodal endopod of B. elegans is small and distally pointed with no setae, where- as in B. beargulchensis it is large, oval, and setose.
Although Bairdops is superficially similar to Archaeocaris, the former is generally larger. Archaeocaris has a carapace deeply excavated along the middorsal posterior margin, exposing several of the posterior thoracomeres dorsally, but Bairdops has no such excavation. In this regard, Archaeocaris is closer to the advanced tyrannophontid stomatopods, which reduce the length of the entire carapace and expose the 3 posterior thoracomeres completely. Archaeocaris does not have a telson spike and possesses thin, flap-like uropods, whereas Bairdops has a spiked telson and generally more blade-
62
like uropods. Archaeocaris again resembles the more advanced tyrannophontids, in regard to the unarmored telson whereas Bairdops is similar to Perimecturus.
Genus: Perimecturus Peach, 1882
Diagnosis.—Dorsoventrally flattened body. Telson base broadly triangular. Uro- podal exopods strongly blade-like. Uropodal endopods small and atrophied.
Remarks.—There are 2 species of Perimecturus: the Viséan Perimecturus parki (Peach) 1882 in the Calciferous Sandstone Series of Scotland, and the Namurian Peri- mecturus rapax Schram and Horner, 1978, from the Bear Gulch Limestone at the top of the Mississippian of Montana. In addition, Brooks (1969) considered Anthracomysis Van Straelen, 1923, synonymous with Perimecturus but gave no reasons.
The differences between the 2 recognized species of Perimecturus are largely restricted to the tail fan. Long, delicate setae decorate the entire tail of P. parki, but P. rapax has no setae. The telson spike is less than half the length of the telson base in P. rapax. The uropodal protopod of P. parki is smooth and unadorned laterally, whereas that of P. rapax is distally serrate. The abdominal tergites and carapace of P. parki are decorated with 4 longitudinal ridges, but P. rapax has 3 ridges and scattered wart-like decorations.
The generally large size and distinct dorsoventral flattening of Perimecturus make it one of the most distinct of the Late Paleozoic malacostracans.
Order: Palaeostomatopoda incerta sedis
Rodendorf (1961, 1970) described supposed insect wings from the Upper Devonian of the USSR, Eopterum devonicum and Eopteridium striatum. Later he suggested (1972) these might be the uropods of palaeostomatopods. I have examined the original material in Moscow and agree, but am unable to give a definitive identification. They are definitely tail fans of some hoplocaridan or even eumalacostracan, but the speci- mens do not permit more precise identification.
Schram (1979) suggested Perimecturus pattoni Peach 1908 was not a palaeosto- matopod, but possibly a tyrannophontid stomatopod.
Van Straelen (1923) described Perimecturus fraiponti from the Chokier Beds, Namurian, near Liege. From the description and illustration, however, the short car- apace and completely exposed posterior thoracomeres would indicate this is a tyran- nophontid stomatopod. The stratigraphic position of the material would tend to confirm this because palaeostomatopods are not found this high in the section.
DISCUSSION
Members of the subclass Hoplocarida were important constituents of Late Paleo- zoic crustacean faunas. Their morphological diversity and ecologic distribution ex- ceeded that of modern hoplocaridans, now restricted to the highly specialized order, the Stomatopoda (mantis shrimp). The modern stomatopods are the only rapacious, active carnivores among the living crustaceans, other forms such as lobsters and crabs being scavenging, low-level carnivores. This rapacious trend in hoplocaridan evolution developed very early, by Early Mississippian or possibly Late Devonian time. The trend continued without interruption from the primitive palaeostomatopods through the Late Carboniferous archaeostomatopodan tryannophontids into the Mesozoic, where essentially modern stomatopods are first encountered.
The Hoplocarida as a whole have fared poorly in comparison with the Eumala- costraca. Two of the 3 Paleozoic hoplocaridan orders, Aeschronectida Schram, 1969), and the Palaeostomatopoda Brooks, 1962, became extinct in Permo-—Triassic time, whereas the Paleozoic eumalacostracan superorders generally persisted to Mesozoic time and increased their morphologic diversity and geographic dispersion.
The singular success of the modern stomatopods is undoubtedly due to the evo- lution of complex behavior patterns used for a variety of purposes. Resources in limited
63
_areas are partitioned with interspecific behavior patterns (Dingle et al., 1973), and complex patterns of behavior have evolved to communicate both within and between various stomatopod entities (Dingle 1969). In addition, the females of at least some species brood the young in cavities until stage IV molting occurs, effectively protecting the young until an advanced stage in development is reached (Dingle and Caldwell 1972), a habit found elsewhere only in the very successful peracarid eumalacostracans.
Caldwell and Dingle (1975) discuss the degree of armor and aggressive behavior in stomatopods. There are 2 types of raptorial appendages in living stomatopods, spear- ing and smashing forms. The smashers are the more vicious of the 2, possess heavy thoracic appendages with powerful muscles, display very intense and complex aggres- sive behavior patterns, have heavy telson armor, and tend to occupy rock or coral habitats. The spearers are not as heavily armored, less intense in their behavior, and burrow in soft substrates.
Such behavioral and morphologic parameters may have been at least incipiently at work in the palaeostomatopods. None of the palaeostomatopods can be considered heavily armored. The exoskeletons appear to have been only poorly to moderately sclerotized and no evidence of massive mineral deposits for armor is evident. In ad- dition, the palaeostomatopods and tyrannophontid stomatopods had spearing type ap- pendages. Archaeocaris vermiformis and B. beargulchensis clearly had serrate propodi on the thoracic raptorial subchelae. The habitats of all the palaeostomatopods seem to have been soft bottom and the dorsoventral flattened morphology of Perimecturus suggests a form adapted to lying partially buried and hidden in the sediment while waiting to ambush its next meal.
Modern stomatopod evolution seems to have moved from the less armored to the more armored, and there are indications the same might have occurred in paleosto- matopod lines. For example, the tail fan of the Viséan Perimecturus parki is more delicately ornamented and seemingly not as well sclerotized than that of the simpler, blade-like, and serrated elements in the tail of the Namurian P. rapax. Viséan Bairdops elegans has a small undistinguished tail fan when compared to the spiked and serrate elements in the tail of B. beargulchensis of the Namurian.
As to what the events were that preceded the extinction of the palaeostomatopods and the rise of the stomatopods is difficult to assess. The success of stomatopods is undoubtedly related to the sophistication of their behavior. Palaeostomatopod behav- ior, aside from the generalities expressed above, is impossible to determine. Behavior in stomatopods is linked with limb specializations (Caldwell and Dingle 1975). Cisne (1974) used the Brillouin Expression (h = [1/N]log,[N!/(N,!N,!...N.!)]) to measure limb specialization and tagmatization, and employing this method the following values are obtained:
Palaeostomatopoda Dele Perimecturus parki
Archaeostomatopodia 22, Tyrannophontes theridion
Opisterostomatopodia D753 )5)
Squilla mantis.
Some question exists for the exact values of the fossil groups. The morphology of the Ist thoracopod is unknown in any of these forms as to whether it is raptorial like the 2nd through Sth thoracopods (value of 2.12), or whether the Ist thoracopod is specialized in some way (value of 2.25) like that seen in the living stomatopods. It would seem from body morphology that the values given here express the lower level of palaeostomatopod limb specialization and body tagmatization, i.e., the stomatopod morphology (even that of the primitive tyrannophontids) was probably more effectively
64
able to handle the ecologic and behavioral parameters to survive as active, rapacious carnivores.
This replacement of palaeostomatopods by archaeostomatopodeans was going on by Namurian time in the middle of the Carboniferous. Tyrannophontes existed with palaeostomatopods in the uppermost Mississippian Bear Gulch Fauna (Schram and Horner 1978), and may have come into being somewhat earlier (Schram 1979). Later faunas such as the Middle Pennsylvanian, Westphalian C, Mazon Creek, Essex Fauna completely lack any palaeostomatopods (Schram 1969b, 1976).
KEY TO PALAEOSTOMATOPODA
Because the hoplocaridans and especially the palaeostomatopods are such impor- tant crustacean elements in Late Paleozoic faunas, a key is provided here to act asa guide in identifying the known forms.
laseSeven segmentsrnmtne abG@Omem. 2 = ci. cs 6 ss oe seine ra ouch Phyllocarida [bpeSixesepmentsimathe Abd OMEN tise 22). noe oe oc ete 0 oe olan te adel cele n eer 2 2a. Abdomen and cephalothorax about equal in size ............. Eumalacostraca 2br eAbdomentanvertham cephalothonrax 2-125)... -2 ls ae ersretn ote eter ener eee 3 Sas DNOLAcicrappendagesmUNSpeCialiZeds 2. 56.0). ss ceile soe ree Aeschronectida Sb Antenonmthoracie appendages subchelate 2... 1/5/18). eerie ote cane rte 4 4a. Carapace completely exposing the last 3 thoracic segments dorsally and
laterallliye Peete seer tar ated here atucl. chetsseSetals causes s Wataacghoee ape Tyrannophontidae 4b. Carapace covering all thoracic segments, at least laterally ................. 5 5a. Carapace covering thoracic segments dorsally and laterally, telson with
Prominent) cegmmallspikcCi Gets =. stele te Seater) rss cl ale ieee etn hel once neater 6 5b. Carapace excavated along dorsal, posterior margin to expose dorsal portion
of thoracomeres, telson suboval with no prominent spike ............... 9 GaseBbodyedorsoventralily fattened: 523) se a). is 0.0 « eel eure i (Perimecturus) 7 6bBodyssubcvlindnicall. mere eet Ae A sas a8 aes sy Sine Dae ho eee (Bairdops) 8
7a. Telson spike less than half the length of telson base, entire tail fan with long, hair-like setae, uropodal protopod with posterior spike between Endo wanadkexOpOdSpee te kee ae eae Hiaht aa bees e alate ee Perimecturus parki 7b. Telson spike more than half the length of telson base, no setae, endopods distally serrate, and telson serrate near caudal furca, uropodal protopod with posterior spike flanking the telson................. Perimecturus rapax 8a. Tail fan without setae or serrations, telson spike less than half the length of telsomabasee tery sel cee tetas ead a ORG ontals eee Bairdops elegans 8b. Uropod margins setose, uropodal exopod laterally serrate, telson spike more than half the length of the telson base ........ Bairdops beargulchensis 9a. Exoskeleton moderately well sclerotized, abdominal pleura sculptured and marked with furrow, mandible well developed with a mandible width:
body length ratio approximately .043............. Archaeocaris vermiformis 9b. Exoskeleton thin and poorly sclerotized, abdominal pleura simple, mandi- ble=width: body ratio about -O23r0mless™ = s.a45-+..-: Archaeocaris graffhami
LITERATURE CITED
Brooks, H. K. 1962. Paleozoic Eumalacostraca of North America. Bulletins of American Paleontology 44(202): 163-338.
1969. Palaeostomatopoda. Pages R533—R535 in R. C. Moore, editor. Treatise on Invertebrate Paleontology, Part R, Arthoropoda 4(2). Geological Society of America and University of Kansas Press.
Caldwell, R. L., and H. Dingle. 1975. Ecology and evolution of agonistic behavior in Stomatopods. Die Naturwissenschaften 62:214—222.
Cisne, J. L. 1974. Evolution of the world fauna of aquatic free living arthropods. Evolution 28:337—366.
Dingle, H. 1969. A statistical and informational analysis of aggressive communication in the mantis shrimp Gonodactylus bredini Manning. Animal Behaviour 17:561—575.
, and R. L. Caldwell. 1972. Reproductive and maternal behavior of the mantis shrimp Gonodactylus
bredini Manning. Biological Bulletin 142:417—426.
65
Dingle, H., R. C. Highsmith, K. E. Evans, and R. L. Caldwell. 1973. Interspecific behavior in tropical reef stomatopods and its possible ecological significance. Oecologia 13:55-64.
Elias, M. K., and C. C. Branson. 1959. Type section of the Caney Shale. Oklahoma Geological Survey, Circular 52. 24 pp.
Meek, F. B. 1872. Descriptions of new western Paleozoic fossils, mainly from the Cincinnati group of the Lower Silurian Series of Ohio. Proceedings of the Academy of Natural Sciences of Philadelphia 24:335— 336.
1875. Invertebrate fossils of the Waverly Group and Coal Measures of Ohio. Report of the Geo- logical Survey of Ohio 2(2):273-325.
Ortmann, A. E. 1897. The systematic position of Crangopsis vermiformis (Meek) from the subcarboniferous rocks of Kentucky. American Journal of Science. Series 4, 4:283—289.
Peach, B. N. 1882. On some new Crustacea from the Lower Carboniferous rocks of Eskdale and Liddesdale. Proceedings of the Royal Society of Edinburgh 30:73-91.
1908. A monograph on the higher Crustacea of the Carboniferous rocks of Scotland. Geological Survey of Great Britain, Paleontological Memoirs 1908. 82 pp.
Rodendorf, B. B. 1961. Opisanie pervogo krilatogo nasekomogo iz devonskikh otlezhenii timana (Insecta, Pterygota). Entomologiecheskoe obozrenie 40:485—489.
. 1970. Vtoraya nadhodka ostatkov krylatykh Devonskikh nasekomykh. Entomologiecheskoe
obozrenie 49(4):835—837.
. 1972. Devonskie zotsteridy—ne nasekomye, a rakoobraznie Eumalacostraca. centomologiecheskoe obozrenie 51(1):96-97.
Sandberg, C. A., and F. G. Poole. 1970. Conodont biostratigraphy and age of West Range Limestone and Pilot Shale at Bactrian Mountain, Pahranagat Range, Nevada. Geological Society of America Abstracts with Programs 2(2):139.
Schram, F. R. 1969a. The stratigraphic distribution of the Paleozoic Eumalacostraca. Fieldiana: Geology 12:213-234.
1969b. Some Middle Pennsylvanian Hoplocarida and their phylogenetic significance. Fieldiana:
Geology 12:235-289.
. 1976. Some notes on Pennsylvanian crustaceans in the Illinois Basin. Fieldiana: Geology 35:21-28.
—. 1979. British Carboniferous Malacostraca. Fieldiana: Geology 40:1—129.
, and J. Horner. 1978. Crustacea of the Bear Gulch Limestone, Mississippian of Montana. Journal of Paleontology 52:394—406.
Van Straelen, V. 1923. Quelques Eumalacostraces nouveaux du Westphalien inferieur d’Argentean pres Liege. Annals de la Societe Geologique Belgique 45:m35—m40.
1931. Crustacea Eumalacostraca. Fossilum Catalogus, Animalia Part 48. 98 pp.
TRANSACTIONS
e OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 6 pp. 67-74 19 September 1979
Limulines of the Mississippian Bear Gulch Limestone of Central Montana, USA
Frederick R. Schram
Abstract. The limuline Merostomata of the Bear Gulch Limestone of the Mississippian of Mon- tana are described. Two forms are recognized. Paleolimulus longispinus sp. nov. is the more frequent of the forms, and Euproops sp. occurs as only a few poorly preserved specimens.
INTRODUCTION
The invertebrates of the Mississippian Bear Gulch Limestone are known to contain malacostracan Crustacea (Schram and Horner, 1978), Annelida and other worm groups (Schram, in press), and conodont eaters (Melton and Scott, 1972: Scott, 1973), as well as pelecypods, gastropods, cephalopods, and articulate and inarticulate brachio- pods. The fauna of the Bear Gulch Limestone is collected from several outcrops in Fergus County, near Beckett, Montana.
Two limuline merostomes have been found in the fauna. The more common of the two is a new species of Paleolimulus Dunbar, 1923. In addition,.some material assign- able to the genus Euproops Meek, 1867, is recognized, but the specimens are too poorly preserved to identify as to species. »
Abbreviations: UM—University of Montana, Missoula; CM—Carnegie Museum of Natural History, Pittsburgh, Pennsylvania.
DISCUSSION
The merostome material is not particularly common in the Bear Gulch fauna as a whole. Twelve specimens of Paleolimulus longispinus are presently known. Only 1 specimen can be identified definitely as Euproops, but 2 other fragmentary specimens may be assignable here.
All specimens are generally preserved as molds, and/or texture differences in the rock with little actual relief. Specimens UM 5558, CM 33986, and CM 33987 do have some organic residues preserved but these contribute nothing to the understanding of the fossils as such. CM 33985 preserves a prosomal appendage as a color difference in the rock, a form of preservation common in the Carboniferous Lagerstatten.
In terms of faunal affinities, these merostomes verify what was seen in the crus- tacean (Schram and Horner, 1978) and worm (Schram, in press) elements of the Bear Gulch fauna. There is a close similarity to the Mazon Creek Essex fauna. Paleolimulus is the dominant merostome. Euproops danae is the characteristic limuline of the Mazon Creek fresh to brackish water Braidwood Fauna and rarely occurs in the nearshore marine Essex Fauna.
68
1 cm.
counterparts of holotype. Scale =
inus sp. nov., UM 5559,
gisp
Paleolimulus lon
Fic. 1.
69
TABLE 1. Measurements (in centimetres) of Paleolimulus longispinus. *holotype.
Prosoma Opisthosoma Specimen Length Width Length Width Telson length UM 5559* AST 5.20 2.07 ~4.10 > 1.66 CM 33946 Ded a 1.84 na on CM 33947 2.87 5.05 1.87 es CM 33983 DS 8 1.88 3)55) 59), i\5) CM 33984 2.33 4.65 1.66 ~=3.05 >1.60 CM 33985 2.78 4.24 1.65 3375) i CM 33994 at 5.48 DAT 3.60 5.45 CM 33995 2.90 ake 72,335) ae 3.98 CM 33996 2.30 4.72 1.82 3.28 CM 33997 2.92 =2.0 ni CM 33998 2.67 2.20 ~=2.90
SYSTEMATIC PALEONTOLOGY
Phylum Cheliceriformes Schram. 1978 Subphylum Chelicerata Haymons, 1901 Class Merostomata Dana, 1852 Subclass Xiphosura Latreille, 1802 Order Xiphosurida Latreille, 1802 Suborder Limulina Richter & Richter, 1929 Infraorder Limulicina Richter & Richter, 1929 Superfamily Limulacea Zittel, 1885 Family Paleolimulidae Raymond, 1944 Genus Paleolimulus Dunbar, 1923 Paleolimulus longispinus sp. nov.
Holotype.—UM 5559 (Fig. 1).
Other material.—CM 33946, CM 33947, CM 33983-CM 33985, CM 33994-CM 34000.
Horizon and locality.—as indicated in the Introduction.
Diagnosis.—Ophthalmic ridges slight. Interophthalmic region broad, extending to near anterior prosomal margin. Slight genal spines. Opisthosoma rounded. Pretelsonic free segment flanked by spines from posterior of axial lobe. Eight or 9 marginal opis- thosomal spines alternating in size. Telson very long.
Description.—The ratio of prosomal width to length is 1.9:1. The interophthalmic area is broad and semicircular and extends to near the anterior margin of the prosoma. The eyes are not well preserved. The cardiac lobe is subtriangular, about % the length of the prosoma, and is connected to the ophthalmic ridge by a faint anterior extension of the cardiac apex. Four faint muscle scar lobations flank the main cardiac lobe. The genal spines are small.
The opisthosoma is somewhat semicircular. The margin is developed as a shelf from which 8 or 9 spines are articulated. The spines alternate posteriorly in size be- tween long and short. The axial lobe is narrower posteriorly than anteriorly. The lobe is produced posteriorly as 2 curved spines that flank the pretelsonic segment and extend beyond the posterior margin of the opisthosoma. The telson is moderately wide and very long, though seldom preserved in its entire length.
The holotype, UM 5559, and CM 33985 preserve portions of a prosomal appen- dage. Nothing is distinctive about them. They are chelate. The segment proximal to the chela on CM 339835 is quite long and the segment proximal to that is of indeterminate length.
Measurements of P. longispinus are given in Table 1, and a reconstruction is offered in Fig. 2.
70
Fic. 2. Paleolimulus longispinus sp. nov. (reconstruction).
Remarks.—Dunbar (1923) described the genus and species Paleolimulus avitus from the Lower Permian Elmo Limestone Member of the Wellington Shale of Elmo, Kansas, USA. Paleolimulus avitus differs from P. longispinus in having somewhat longer and more outwardly directed genal spines. The ophthalmic ridges of P. avitus are very prominent and are bilobed, meeting with the apex of the cardiac lobe, and the interophthalmic area is relatively narrow. The opisthosoma is narrower and more elon- gate than that of P. /Jongispinus, and there were apparently only 4 or 5 small marginal spines on the opisthosoma. The ratio of prosomal width to length of P. avitus, based on Dunbar’s material and that of Raymond (1944), is 1.67:1.
A comparison of the known species of Paleolimulus is presented in Table 2. Dunbar (1923) included in the genus Paleolimulus, P. signatus (Beecher), 1904, and P. randalli (Beecher), 1902. Paleolimulus signatus is somewhat stratigraphically lower in the Fort Riley Limestone of Kansas than P. avitus. The single known specimen of P. signatus is an incomplete prosoma but it is >3x larger than that of P. avitus. The anatomy is very similar, however, and more and better material of these species may reveal that P. avitus is conspecific with P. signatus. Paleolimulus randalli is from the
71
‘oytsadsuos
oq Aeu snjpUsIS
snolayuogied 1addp WIOFJIUN Q ayesu0[q aye1NpOW 98° sisuaupsaanl * gq uelUoAaqd Jsddy és é dUuON é WJDpuva * URIWIIg I9MO'T OYS ¢-p aye3u0[q ad1e[—I}e1NpPO|W L9'1 SNIIAD “gq URIWIdg IOMOT é R é fi, SNIDUBIS *q A]10119}s0d JOYS pue BuO] 97eu19}/e ueiddississtp toddq 6-8 popunoy [Tews 06'1 snuidsisuo] *d a3V souids odeys souids jeusy (yy3U9] sa1sedsg jewosoujsidg ewosoylsidg :YIpPIM) eWOSOIg’
‘qd pue snjiav “gq ‘snjnwioappg Jo saiseds
uMOUY 24} JO
uosuedwo) “7 a1dV I
Fic. 3. Euproops sp., UM 5558. Note: prosoma is much broader than long and opisthosoma is segmented. Scale = 1 cm.
Upper Devonian Chemung Sandstone. It too is an incomplete prosoma but differs from any other Paleolimulus material in having an anteriorly narrow cardiac lobe and, al- though the posterior prosomal margin is quite concave, apparently no genal spines. Finally, Chernyshev (1933) described Paleolimulus juresanensis from the Upper Carboniferous of the Urals on the Yurezan River. He had a single ventrally preserved specimen. As a result, it is difficult to compare P. juresanensis to the other species. The prosomal width to length ratio is 1.86:1. Although there are 8 marginal opistho- somal spines, the spines appear to be all the same length, and the opisthosoma is more elongate than rounded. As far as can be deduced, P. juresanensis appears to be a distinct species, though probably taxonomically closer to P. longispinus than the other species of Paleolimulus. But it should be remembered that dorsal preservations of the Soviet material are necessary before definitive taxonomic judgments can be made.
Superfamily Euproopacea Eller, 1938 Family Euproopidae Eller, 1938 Genus Euproops Meek, 1867 Euproops sp.
Material.—UM 5558, ?CM 33986, ?CM 33987.
Horizon and locality.—as indicated in the Introduction.
Remarks.—One specimen, UM 5558 (Fig. 3), seems to be definitely a member of the genus Euproops. Though the specimen is poorly preserved, several features allow it to be identified as a euproopid. The prosoma is markedly wider than long, with a width to length ratio of 2.8:1, and appears to bear carinate ophthalmic spines. The opisthosoma is clearly segmented across its entire width. In addition, CM 33986 and CM 33987 may also be euproopids based on shape of what appears to be the prosoma. But these latter 2 specimens are very poorly preserved.
The measurements of UM 5558 are: prosomal length, 2.03 cm; prosomal width, 5.66 cm; opisthosomal length, 2.42 cm; opisthosomal width, 3.63 cm.
ACKNOWLEDGMENTS
Thanks must be extended to W. Melton, University of Montana, Richard Lund, Adelphi University, and John Carter, Carnegie Museum, for making these specimens
W3
available for study. The reconstruction in Fig. 2 was executed by Tony D’Attilio of
the San Diego Natural History Museum.
LITERATURE CITED
Beecher, C. E. 1902. Note on a new xiphosuran from the Upper Devonian of Pennsylvania. American Geologist 29: 143-146.
Beecher, C. E. 1904. Notes on a new Permian xiphosuran from Kansas. American Journal of Science (4)18:23-24.
Chernychev, B. I. 1933. Arthropoda s urala i dru- gukh mest SSSR. Materiali tsentralnogo nauchno-issledovatelskogo geologo-razve- dochnogo instituta paleontologiya u stratigra- fiya 1:15—24.
Dunbar, C. O. 1923. Kansas Permian insects. Part 2. Paleolimulus, a new genus of Paleozoic Xiphosura. with notes on other genera. Amer- ican Journal of Science (5)5:443-454.
Meek, F. B. 1867. Notes on a new genus of fossil Crustacea. American Journal of Science (2)43:394-395.
Melton, W. G., and Scott, H. W. 1972. Conodont
bearing animal from the Bear Gulch Lime- stone, Montana. Geological Society of Amer- ica Special Paper 141:31-65.
Raymond, P. E. 1944. Late Paleozoic Xiphos- urans. Bulletin, Museum of Comparative Zo- ology 94:475—S08.
Schram, F. R. in press. Worms of the Mississip- pian Bear Gulch Limestone of central Mon- tana. Transactions of the San Diego Society of Natural History.
Schram, F. R., and Horner, J. 1978. Crustacea of the Mississippian Bear Gulch Limestone of central Montana. Journal of Paleontology 52:394-406.
Scott, H. W. 1973. New Conodontochordata from the Bear Gulch Limestone. Michigan State University Paleontology Series 1:85—99.
Department of Paleontology, San Diego Natural History Museum, San Diego, Cali-
fornia 92112 USA.
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 7 pp. 75-84 19 September 1979
A new species of chiton (Mollusca: Polyplacophora) from the Hawaiian Islands and Tahiti
Antonio J. Ferreira and Hans Bertsch
Abstract. Chitons of the genus Plaxiphora are predominantly cold and temperate water southern hemisphere species. The new species described here occurs in tropical and northern subtropical central Pacific waters. To the impoverished Polynesian chiton fauna is now added the new species, Plaxiphora kamehamehae Ferreira and Bertsch, sp. nov.
INTRODUCTION
In over a century of malacological research, only 4 species of chitons have been described from the Hawaiian Islands: Ischnochiton petaloides (Gould, 1846), Acan- thochitona viridis (Pease, 1872), Acanthochitona armata (Pease, 1872) (probably syn- onymous with A. viridis), and Rhyssoplax linsleyi (Burghardt, 1973). The marked scar- city of chitons in Hawaii (both in numbers of species and individuals) has been noted by Pease (1872), Kay (1967) and Burghardt (1973). Therefore it is rather surprising that intertidal collecting on the island of Oahu has yielded specimens of a hitherto unde- scribed species of chiton. Even more remarkable is the fact that the genus to which this species belongs is known mostly from the temperate and cold water faunal regions of the southern hemisphere.
This work is based upon material deposited in the California Academy of Sciences, Departments of Invertebrate Zoology (CASIZ) and Geology (CASG), San Francisco, California; San Diego Natural History Museum (SDNH), California; Australian Mu- seum, Sydney (SAM); South African Museum, Cape Town; and in the A. J. Ferreira collection.
SYSTEMATICS
Class POLYPLACOPHORA Blainville, 1816 Order NEOLORICATA Bergenhayn, 1955 Suborder ISCHNOCHITONINA Bergenhayn, 1930 Family MOPALIIDAE Dall, 1889 Genus PLAXIPHORA Gray, 1847 Plaxiphora kamehamehae Ferreira & Bertsch, sp. nov.
Material examined.—1) 2 specimens; Ft. Kamehameha Beach, Oahu, Hawaii (approx. 21°19'N; 157°57'W), on the eastern shore of the entrance to Pearl Harbor; /eg. H. Bertsch, 24 September 1977.
2) 1 specimen; Ft. Kamehameha Beach; Jeg. H. Bertsch, 15 October 1977.
3) 3 specimens; Ft. Kamehameha Beach; Jeg. H. Bertsch, 5 November 1977.
4) 8 specimens; Ft. Kamehameha Beach; Jeg. H. Bertsch, Shannon Norstrom and Erin Myhill, 12 November 1977. (Holotype specimen taken from this lot.)
5) 43 specimens; Ft. Kamehameha Beach; leg. Leonce Many and Neal Voelz (Earthwatch Expedition participants), Scott Johnson and H. Bertsch, 6 June 1978.
6) 5 specimens; Aue, Papeete, Tahiti (17°32'S:; 149°34'W); leg. George Hanselman, July 1971.
Diagnosis.—Small chiton, oval shaped, round backed, light colored (Fig. 1A). Valves (Figs. 1B-D) strongly beaked, almost sculptureless. Tegmentum granulose,
76
Fic. 1. (A). Plaxiphora kamehamehae Ferreira and Bertsch, sp. nov. Paratype, 10.5 mm long (including girdle); (B). Plaxiphora kamehamehae; holotype: close-up of valves v and vi; (C). Plaxiphora kamehame- hae; holotype: close-up of valves i and viii, (D). Plaxiphora kamehamehae, holotype: articulamentar sur- face of valves i and viii.
granulations in quincunx except in pleural areas where arranged longitudinally. Lateral areas weakly defined by two shallow, rib-like radial undulations. Posterior valve tri- angular, mucro posterior. Articulamentum of 8-10 projecting teeth in valve 1; inter- mediate valves one-slitted. No teeth in valve viii, insertion plate reduced to a callus
VW
100MM
Fic. 2. Plaxiphora kamehamehae. Radula of holotype. (A). Median and first lateral teeth; (B). Major (second) lateral tooth.
vaguely hollowed out in the middle line by a shallow sinus. Sutural plates well devel- oped, rectangular in valve viii, round to oval in other valves. Sinus round and deep. Radula (Fig. 2) with tricuspid major lateral teeth. Girdle (Fig. 3) covered with minute spiculoid scales and randomly placed hairy bristles.
Description of holotype.—The holotype is the largest in a series of 8 specimens collected at Fort Kamehameha Beach, 12 November 1977. It measures (including gir- dle) 13.0 mm long, and 8.7 mm wide at the iv valve level. The general shape of the specimen is oval, round backed, with strongly beaked valves. Once cleaned of en- crustations, mostly algae, the specimen is seen to be light colored. It is white in the middle of valve i, and most of valves ii to. vii, with a contrasting dark gray on the sides of valve i, and most of valves vi to viii, except for a white jugal area with linear smudges of red. Small spots of bright blue green and brown give a mottled appearance to the pleural areas of valves v and vi.
The tegmentum is sculptureless except for its coarsely granular surface that can be seen under magnification. The tegmental granulations are mostly round and arranged in quincunx; in the pleural areas, the granulations tend to be arranged in longitudinal rows, but not conspicuously. With the benefit of tangential light, the anterior valve shows approximately 8 very faint, almost imperceptible radial ribs. In the intermediate valves, the lateral areas are only slightly raised, and display 2 low-arched radial ribs or undulations with a shallow area in between; the lateral areas are much more in evidence in the anterior (ii and iii) than in the posterior (vi and vii) valves. The central areas are sculptureless, except for the quincunxially arranged granulations of the teg- mental surface. The posterior valve is rather flat, slightly longer than wide, and tri- angular. The mucro is terminal on the somewhat thickened posterior edge of the valve, but not raised or upswept.
The articulamentum is white but translucent enough to allow some of the tegmental colors to show through. The sutural laminae are well developed, separated by a wide, round, deeply cut sinus; in shape, they are triangular on valve 11, semicircular on valves iii-vi, and mostly rectangular in valves vii and viii. Eaves are narrow but spongy.
The insertion plate of valve i is well developed, projecting downwards, cut into sharp, strong teeth, markedly striated on their outer surface; it displays 10 slits, 8 of
78
Cc
Fic. 3. Plaxiphora kamehamehae. Girdle elements. (A). Spiculoid scales of the upper surface; (B). Cross- section of corneous bristle; (C). Scales of the undersurface near outer margin.
which correspond in position to the very vaguely defined radial ribs of the tegmentum. The intermediate valves are one-slitted. The posterior valve has no slits or teeth; its insertion plate is limited to a thick callus, slightly ridged along its free edge, and hollowed out in the midline to form a shallow sinus.
The girdle, fleshy and light tan, is loosely covered with minute spiculoid scales (Fig. 3A) that do not imbricate. These scales measure about 60 um in height, and 20 ym in width; they are translucent or golden, and mostly round with a blunt free end. Amid the spiculoid scales there are long, corneous, hairy bristles with a faintly longi- tudinal texture, bespeaking their fascicular makeup as seen in cross-section (Fig. 3B); these bristles attain as much as 0.8 mm in length, and 80 um in width at the base. In the inner half of the girdle, these corneous processes show a tendency to aggregate in sutural tufts of 3—4 bristles; their distribution in the outer half of the girdle seems to be quite random. At the outer margin, the girdle displays a spicular fringe, the spicules having a clearly longitudinal texture and measuring as much as 300 um in length and 45 um in thickness.
79
The underside of the girdle is loosely covered with transparent scales, mostly round (10 x 10 um) at the inner margin, but becoming pointed and elongated (75 x 10 ym) toward the outer margin (Fig. 3C).
The gills, abanal and merobranchial, extend for about *5 of the length of the foot; they consist of about 24 plumes on each side.
The radula measures 4.0 mm in length (31% of the length of the specimen), and comprises some 40 rows of mature teeth. The median tooth (Fig. 2A) is about 60 um long, 25 «wm in width anteriorly, with a small blade. The tooth has a dumbbell shape. The first lateral teeth are about 60 wm in length, and show a twice undulated outer edge (Fig. 2A). The major lateral teeth measure about 210 ym in length; they bear a tricuspid blade, about 75 x 75 um in size, with the middle cusp slightly longer than the other (Fig. 2B). The outer marginal teeth are elongated, measuring about 100 ~m in length, 60 ~m in width.
Type locality. —Fort Kamehameha Beach, Oahu, Hawaiian Islands (approximately 21°19’N:; 157°57'W); intertidal zone on the eastern edge of the channel entrance to Pearl Harbor.
Type material.—Holotype, disarticulated, with radula and girdle mounted sepa- rately, is deposited at the San Diego Natural History Museum, Department of Marine Invertebrates (Type Series No. 503). Paratypes are deposited at the California Acad- emy of Sciences (CASIZ Type Series No. 00713), the Natural History Museum of Los Angeles County, the Bernice P. Bishop Museum, and the San Diego Natural History Museum (Marine Invertebrates, Type Series No. 512).
DISCUSSION
There has been a tendency to recognize within the genus Plaxiphora Gray, 1847 (Type species: Chiton carmichaelis Gray, 1828 [=Chiton auratus Spalowsky, 1795] by original designation) many subgenera, mostly monotypic: Frembleya H. Adams, 1867, Guildingia Dall, 1882, Diaphoroplax Iredale, 1914, Poneroplax Iredale, 1914, Maori- chiton Iredale, 1914, Aerilamma Hull, 1924, and Mercatora Leloup, 1942. This pro- cedure seems taxonomically unsound in view of the relatively minor morphological differences that distinguish the taxa referable to Plaxiphora. Although a formal review of the genus Plaxiphora is not intended here, it is apparent that the use of such subge- neric group names is unwarranted.
The genus Plaxiphora is known mostly from the cold and ismpee waters of the southern hemisphere (Fig. 4). In a review of the genus, Leloup (1942) reduced the 50- odd nominal species assigned to Plaxiphora to 11 valid species; to Leloup’s list, 2 other species are here added, P. primordia (Hull, 1924), and P. kamehamehae (Ta- ble 1):
Plaxiphora kamehamehae is differentiated easily from all other species of Plaxi- phora. Comparison was made between specimens of P. mercatoris (from Easter Island: CASIZ G-28236; CASG 34805: CASG 37061; AJF Coll. ex B. F. Alarcon), P. simplex (from Tristan da Cunha: CASG 54471; AJF Coll. ex P. Kaas), P. albida (from southern Australia: SAM c42055; SAM c42056; SAM c108791; SAM c108792; SAM c108793; CASG 34675: CASG 36339; CASG 36810; CASIZ 009290), P. mathewsi (from southern Australia: SAM c39877; SAM c108794; CASG 54385; AJF Coll. ex J. R. Penprase), P. primordia (from northeastern Australia: SAM c108795; SAM c108796), P. obtecta (from New Zealand: CASIZ 009292), P. aurata (from the Falkland Islands: CASIZ 00921: and from Chiloe Island, Chile, AJF Coll. ex E. Bay-Schmith), and P. parva (from Inhambane, Mozambique: South African Museum No 32624). Plaxiphora kamehamehae is distinct in size (Table 1), coloration, tegmental sculpture, and aes elements. Furthermore, although the other species examined are holobranchial, kamehamehae is merobranchial.
In its small size, Plaxiphora kamehamehae ranks with P. parva and P. primordia, to which it is also similar in the color, the granular tegmental surface, and the form of the girdle elements. Plaxiphora parva is known only from Nierstrasz’ original descrip-
80
Fic. 4. Records of Plaxiphora species.
tion and a single specimen referred to by Barnard (1963:332-333, figs. 29c-e). This latter specimen was examined on a loan through the generosity of Elizabeth K. Giles, South Africa Museum. Plaxiphora kamehamehae differs from P. parva by (1) the finer, smaller, and more regular granulations to the tegmentum,; (2) the much less defined lateral areas, and (3) the triangular (rather than semicircular) outline of the posterior valve.
Plaxiphora kamehamehae differs from P. primordia by (1) the much more uniform shape of the tegmental granulations, and their greater tendency to remain in quincunx, and (2) the structure of the median and first lateral radular teeth. For comparison, the
TABLE |. Species of Plaxiphora Gray, 1847, presently regarded as valid, their general locality, and maximum reported size.
Maximum reported Species length (mm) Distribution Sub-Antarctica to Valparaiso, P. aurata (Spalowsky, 1795) 70 and New Zealand South Australia, Gulf of P. albida (Blainville, 1825) 70 Oman (?) P. caelata (Reeve, 1847) 35 New Zealand P. biramosa (Quoy and Gaimard, 50 New Zealand 1853) P. egregia (Adams, 1867) 18 New Zealand P. simplex (Haddon, 1886) 45 Tristan da Cunha Island P. obtecta Carpenter in Pilsbry, 1893 45 New Zealand P. parva Nierstrasz, 1906 7 Mozambique, Ceylon (?) P. fernandezi Thiele, 1909 18 Juan Fernandez Island P. mathewsi (Iredale, 1910) 1S S. Australia P. primordia (Hull, 1924) 15 NE Australia P. mercatoris Leloup, 1936 30 Easter Island P. kamehamehae Ferreira and 13 Hawaii; Tahiti
Bertsch, sp. nov.
81
Fic. 5. Radula of Plaxiphora primordia (Hull, 1924). (A). Median and first lateral teeth; (B). Head of second (major) lateral tooth.
significant radular elements of P. primordia are illustrated here for the first time (Fig. 5). The specimen of P. primordia (SAM c108796: Lindeman Island, Queensland, Aus- tralia) measures 8.4 mm in length; the radula measures 2.4 mm in length (28% of the whole specimen) and comprises 30 rows of mature teeth. The outer marginal teeth are elongated, about 80 um in length, 50 um in width. Still, the similarities between P. kamehamehae and P. primordia are such as to suggest a common origin.
The specimens of Plaxiphora kamehamehae from Hawaii were found in <1 metre of water, attached to the sides of dead coral pieces, usually occupying a depression or pit suggestive of a homing scar. Most commonly both the substrate and the chiton were covered by encrusting coralline algae. The animals are extremely cryptic in their habitat and can be seen only by careful searching. Further details of this habitat (and associated organisms) are described by Bertsch and Johnson (1979).
During the writing of this paper, Col. George A. Hanselman recognized Plaxiphora kamehamehae as very similar to specimens that he had collected in Tahiti. The study of these Tahitian specimens showed that they were indeed conspecific with those from Hawaii. One specimen 8.7 mm long was disarticulated. It has a slit formula of 8-1-0, with a blue articulamentum (the only noted difference from the Hawaiian specimens examined, whose articulamentum is white). The radula of this disarticulated Tahitian specimen measures 3.0 mm long, and it comprises about 35 rows of mature teeth.
In Tahiti, Plaxiphora kamehamehae occurred *‘on the side of fairly smooth granite rocks, about head-size or larger . . . coated with a somewhat slimy mossy algae; they were uniformly nestled into small rough spots on the rocks. The site . . . has since been destroyed during highway construction’ (personal communication, George A. Hanselman, 7 December 1978).
The presence of Plaxiphora kamehamehae in Tahiti as well as Hawaii strongly suggests that it might also be present on many other Indo-Pacific islands. Its cryptic nestling behavior, common to the Hawaiian and Tahitian animals, may prevent it from readily being found.
Six additional specimens of Plaxiphora kamehamehae were collected at Ft. Kame- hameha Beach on 14 July 1979 by Dean Pitts and Tom Knapik, members of the Hawaiian Mollusks 1979 Earthwatch team.
Etymology.—This new species of Plaxiphora is named kamehamehae (genitive ending, first declension masculine noun) after the first king of all the Hawaiian Islands. King Kamehameha I ruled from 1795 (when he finally conquered the island of Oahu at the Battle of Nuuanu by his forces pushing the opposing troops over the steep Pali cliffs) to 1819. Prior to his rule, the islands had been governed by regional rulers. His was a signficant, pivotal role in Hawaiian history, and even today the monarchy he established affects aspects of life in the Hawaiian Islands.
Other invertebrates named in honor of King Kamehameha include a butterfly (Vanessa tameamea Eschscholtz, 1821), a Pleistocene oyster from the Waianae coast of Oahu (Ostrea kamehameha Pilsbry, 1936), a pulmonate from Molokai (Endodonta kamehameha Pilsbry & Vanatta, 1905), and the prosobranch Mitra kamehameha Pilsbry, 1921 (which is a synonym of M. ustulata Reeve, 1844).
ACKNOWLEDGMENTS
We express our appreciation to the good friends and colleagues who helped with specimens, data, and personal effort in the course of this work. Above all we thank Dalene Drake, Dustin Chivers, Dr. Welton L. Lee, Barry Roth, and Dr. Peter U. Rodda of the California Academy of Sciences, San Francisco; Melanie Miller and Dr. Robert Robertson of the Academy of Sciences of Philadelphia; Dr. Fred E. Wells of the Western Australian Museum, Perth; Ian Loch of the Australian Museum, Sydney; Elizabeth K. Giles of the South African Museum, Cape Town; J. Robert Penprase of West Hobart, Tasmania; Dr. Enrique Bay-Schmith B. of Concepcion, Chile; Aileen Blake of the British Museum (Natural History); Piet Kaas of The Hague, The Neth- erlands: Richard A. Van Belle of Sint-Niklaas, Belgium; Dr. James H. McLean, Nat- ural History Museum of Los Angeles County; and George A. Hanselman, Research Associate of the San Diego Natural History Museum, California. We are grateful to Anthony D’ Attilio, Department of Marine Invertebrates, San Diego Natural History Museum, for assistance with the drawings.
We thank The Center for Field Research for a grant that enabled H. B. to collect specimens in Hawaii during June 1978. Appreciation is expressed to Leonce Many and Neal Voelz, members of the Hawaiian Mollusks 1978 Earthwatch team who collected some of the specimens reported in this paper, and Scott Johnson and Judi Bertsch for assistance in the field.
LITERATURE CITED
Adams, Henry. 1867. Descriptions of six new Burghardt, Glenn E. 1973. A new Hawaiian chi-
species of shells, and notes on Opisthostoma de-Crespignii. Proceedings of the Zoological Society of London 1866:445-447; plt. 38.
Barnard, K. H. 1963. Contributions to the knowl- edge of South African Marine Mollusca. Part IV. Gastropoda: Prosobranchiata: Rhipidog- lossa, Docoglossa. Tectibranchiata. Polypla- cophora. Solenogastres. Scaphopoda. Annals of the South African Museum 47(2):201-360; 30 text figs. (December)
Bergenhayn, J. R. M. 1930. Kurze bemerkungen zur kenntnis der schalenstruktur und syste- matik der Loricaten. Kungl. Svenska Vetens- kapsakademiens Handlingar. 3rd ser. 9(3):3- 54; 10 plts.; 5 text figs. (11 November 1930)
Bergenhayn, J. R. M. 1955. Die fossilen schwed- ischen Loricaten nebst einer vorlaufigen revi- sion des systems der ganzen klasse Loricata. Lunds Universitets Arsskrift N.F. Avd. 2, 51(5):1-47; 2 plts. (3 August 1955)
Bertsch, Hans, and Scott Johnson. 1979. Three new opisthobranch records for the Hawaiian Islands. The Veliger 22(1):41-44; 1 plt. (1 July 1979)
ton, Rhyssoplax linsleyi. Proceedings of the California Academy of Sciences, 4th series 39(21):501—506; 3 text figs. (19 December 1973) Dall, William Healey. 1882. On the genera of chi- tons. Proceedings of the United States Na- tional Museum 4:279-291. (22 February 1882) Dall, William Healey. 1889. Reports on the results of dredging, under the supervision of Alex- ander Agassiz, in the Gulf of Mexico (1877- 78) and in the Caribbean Sea (1879-80), by the U.S. Coast Survey Steamer **Blake,”’ Lieut.- Commander C. D. Sigsbee, U.S.N., and Com- mander J. R. Bartlett, U.S.N., Commanding. XXIX. Report on the Mollusca. Part I. Gas- tropoda and Scaphopoda. Bulletin of the Mu- seum of Comparative Zoology at Harvard Col- lege 18:1-492; plts. X-XL. (8 June 1889) Gould, Augustus Addison. 1846. On the shells collected by the United States Exploring Ex- pedition. Proceedings of the Boston Society of Natural History 2(14):141—-145. (July 1846) Gray, John Edward. 1828. Spicilegia Zoologica; or Original Figures and Short Systematic De- scriptions of New and Unfigured Animals.
Part 1, 8 pp.; 6 pits. British Museum. (1 July 1828)
Gray, John Edward. 1847. On the genera of the family Chitonidae. Proceedings of the Zoolog- ical Society of London 15:63—70. (June 1847)
Haddon, Alfred C. 1886. Report on the Polypla- cophora collected by H.M.S. Challenger dur- ing the years 1873-1876. Challenger Reports 15(43):1-50; plts. 1-3.
Hull, A. F. Bassett. 1924. New Queensland Lor- icates. Proceedings of the Royal Society of Queensland 36:109-116; plt. 21.
Iredale, Tom. 1910. Notes on Polyplacophora, chiefly Australasian (Part 1). Proceedings of the Malacological Society of London 9(2):90- 105. (30 June 1910)
Iredale, Tom. 1914. The chiton fauna of the Ker- madec Islands. Proceedings of the Malaco- logical Society of London 11(1):25—51; plts. 1- 2. (30 March 1914)
Kay, E. Alison. 1967. The composition and rela- tionships of marine molluscan fauna of the Hawaiian Islands. The Venus 25(3—4):94-104; 3 text figs. (July 1967)
Leloup, Eugene. 1936. Chitons recoltés au cours de las Croisiere (1934-1935) du Navire-Ecole Belge ‘‘Mercator.’’ Bulletin du Musee Royal d’Histoire Naturelle de Belgique 12(6):1-10. (March 1936)
Leloup, Eugene. 1942. Contribution a la connais- sance des Polyplacophoras. I. Famille Mopa-
83
liidae Pilsbry, 1892. Memoires du Musee Roy- al d Histoire Naturelle de Belgique, Deuxieme Serie, Fasc. 25:1-64; 6 plts.; 27 text figs. (31 December 1942)
Nierstrasz, Hugo Friedrich. 1906. Beitrage zur Kenntniss der Fauna von Siid Afrika. VI. Chi- tonen aus der Kapkolonie und Natal. Zoolo- gische Jahrbucher, Abtheilung fiir Systematik, Geographie und Biologie der Tiere 23:487- 520; plts. 26-27.
Pease, W. Harper. 1872. Polynesian Chitonidae. American Journal of Conchology 7(3):194— 195. (19 March 1872)
Pilsbry, Henry Augustus. 1892-1895. Polyplaco- phora. In: Tryon, Manual of Conchology. vols. 14 and 15.
Quoy, Jean Rene Constant, and Joseph Paul Gai- mard. 1835. Voyage de decouvertes de 1’ Astrolabe execute par ordre du Roi, pendant les annees 1826—1827—1828—1829, sous le com- mandement de M. J. Dumont d’ Urville. Zoolo- gie, vol. 3. Paris.
Reeve, Lovell Augustus. 1847. Monograph of the genus Chiton. Conchologia Iconica: or, Illus- trations of the shells of molluscous animals. 4:28 plts.; 194 figs. London, Lovell Reeve. (August 1847)
Spalowsky, Jos. 1795. Prodroma in Systema His- toriae Testaceorum. Vienna. (not seen)
Thiele, Johannes. 1909-1910. Revision des Sys- tems der Chitonen. 132 pp.; 10 plts. Stuttgart.
Ferreira: California Academy of Sciences, Golden Gate Park, San Francisco, Cali- fornia 94118, USA; Bertsch: Department of Marine Invertebrates, San Diego Natural History Museum, Balboa Park, San Diego, California 92112, USA.
. od ‘ > eo) a) eel, | pout ales | De mei. Pendle + PON . S
- ; am | , 8 0 Ts + q _=@- -b pei oR ecAsioy al
ry ane ae ter
a . _ a _
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 8 pp. 85-106 12 October 1979
Fossil carrion beetles of Pleistocene California asphalt deposits, with a synopsis of Holocene California Silphidae (Insecta: Coleoptera: Silphidae)
Scott E. Miller! and Stewart B. Peck
Abstract. Fossil Silphidae occur in three late Pleistocene asphalt deposits in California: Rancho La Brea in Los Angeles County, McKittrick in Kern County, and Carpinteria in Santa Barbara County. Pierce’s 1949 Nicrophorus taxa from Rancho La Brea and McKittrick are all new junior synonyms: Nicrophorus guttula labreae, Nicrophorus mckittricki, Nicrophorus obtusiscutellum, and Nicrophorus investigator latifrons = Nicrophorus marginatus Fabricius; Nicrophorus guttula punctostriatus = Nicrophorus guttula (Motschoulsky); Nicrophorus investigator alpha = Nicrophorus nigrita (Man- nerheim). Lectotypes are designated for N. g. labreae and N. i. alpha. The following resurrected generic combinations are used: Thanatophilus lapponicus (Herbst), Heterosilpha ramosa (Say), Het- erosilpha aenescens (Casey). A neotype is designated for Heterosilpha ramosa. Heterosilpha aenes- cens is a valid species and a lectotype is designated for it. The fauna of each deposit includes: Rancho La Brea: T. lapponicus, H. ramosa (and perhaps H. aenescens), N. marginatus, N. guttula, and N. nigrita; McKittrick: N. guttula and N. marginatus; Carpinteria: N. guttula and N. nigrita. Nicro- phorus marginatus is the best represented species of Nicrophorus in the asphalt, although it is the least common species of the genus in the modern southern California fauna. Possible reasons for this apparent faunal change include real faunal changes and biased preservation. Due to limited knowledge of silphid ecology, detailed paleoecological conclusions cannot be made at the present time. All silphid species presently known from California are reviewed, and a key is given. Aclypea bituberosa (LeConte) (new combination) occurs in the Sierra Nevada Mountains, Thanatophilus sagax (Manner- heim) (new combination) is raised from synonymy, Pelatines latus (Mannerheim) is recorded from northern California, a lectotype is designated for Nicrophorus hecate (Bland), and several other geo- graphic ranges are extended.
INTRODUCTION
Pierce (1949) recognized 6 species and 5 subspecies of Silphidae from the Rancho La Brea and McKittrick asphalt deposits. Two of these species and 4 subspecies were described as new. This study reevaluates Pierce’s (1949) taxa and records newly found specimens. In order to place the fossils properly, we review the taxonomy and distri- bution of the Holocene Silphidae of California.
Although most of Pierce’s basic concepts (Pierce 1961) regarding fossil insects were valid, his publications and taxonomic procedures were replete with errors. Se- rious identification problems result from his erection of taxa based on fragmentary specimens. In addition to poor descriptions, some of his drawings were inaccurate (e.g., Carpenter 1968, Matthews and Halffter 1968). Our study was hampered by past improper labeling by Pierce and some errors in cataloging many type specimens by Sphon (1973).
All the Pleistocene specimens studied represent Holocene species and fall within reasonable ranges of morphological variation. The use of subspecific names is not
' Research Associate in Invertebrate Paleontology, Natural History Museum of Los Angeles County. Research Associate in Entomology, San Diego Natural History Museum.
86
justified, because the fossil forms are not geographic races and there is no morpholog- ical basis upon which to found chronosubspecies. Studies by other workers indicate that almost all Pleistocene insect fossils represent extant species (Coope 1970, Mat- thews 1977).
There is confusion regarding proper application of generic and specific names in the Silphidae. Members of the Silphini discussed here usually have been included in Silpha Linnaeus 1758. However, we are presenting several resurrected and new com- binations, in agreement with R. B. Madge’s (personal communication) as yet unpub- lished review of the world Silphini.
Our synonymies cite only original descriptions and important references; more complete synonymies are given by Hatch (1928) and Madge (1958). All fossil silphids we examined are listed in the text, along with appropriate specimen numbers (LACMIP type number, RLP entomology number, and/or Pierce’s number [with **C”’ or **“McK”’ prefix]). All are in LACM, except those from UCMP localities 2051 and 7139. Those not cited by Pierce (1949) are preceded by an asterisk (*).
Abbreviations for collections consulted and cited in the text are:
ANSP Academy of Natural Sciences of Philadelphia;
CAS California Academy of Sciences; CDA California Department of Food and Agriculture; CIT California Institute of Technology (VP collection now housed at LACM);
CMNH_- Carnegie Museum of Natural History;
LACM Natural History Museum of Los Angeles County;
LACMIP LACM Invertebrate Paleontology collection;
MCZ Museum of Comparative Zoology, Harvard University;
RLP Rancho La Brea Project (current LACM excavation of Pit 91); SBMNH Santa Barbara Museum of Natural History;
UCMP — University of California Museum of Paleontology, Berkeley; UCR University of California at Riverside;
USNM _— United States National Museum of Natural History.
We also examined Holocene silphids from the American Museum of Natural History, British Museum (Natural History), California Insect Survey (University of California at Berkeley), Field Museum of Natural History, Peabody Museum (Yale University), San Diego Natural History Museum, University of California at Davis, and our per- sonal collections. Records from the California Channel Islands, compiled in ongoing SBMNH research, are included in the Holocene distribution summaries.
Other abbreviations used in the text are:
BD below datum (for depths within Pit 91, Rancho La Brea); B.P. before present (in radiocarbon dating, present calculated as 1950); loc. locality number; VP vertebrate paleontology. LOCALITIES
Pierce (1949) studied fossil silphids only from the Rancho La Brea and McKittrick asphalt deposits (Pierce 1946, 1947a, 1947b). We studied silphids from these localities and the Carpinteria asphalt deposit. Additional vertebrate fossil bearing asphalt de- posits near Maricopa in Kern County (Macdonald 1967) have yielded no silphids.
RANCHO LA BREA
The Rancho La Brea asphalt deposits are located in Hancock Park, Los Angeles, Los Angeles County, California. More than 100 individual excavations or “‘pits’” have been made since 1905. Most of these were unproductive test holes and fewer than 15 were major sources of fossil vertebrates (Howard 1962, Marcus 1960, Stock 1956). Before the reopening of Pit 91 in 1969, emphasis was placed on large vertebrates;
87
insects and other small fossils were neglected by the early excavators. In addition to Pierce’s material, we have studied silphids salvaged from miscellaneous unsorted ma- terial from several original excavations and silphids recovered in the modern excava- tion of Pit 91.
Most of the silphids from older LACM excavations were studied by Pierce (1949). Silphids from Pits 9, 28, 37, and 81 (excavated between 1913 and 1915) bear no further data than pit number. Pits A and B were excavated in 1929, and Pierce’s ‘‘Bliss 29”’ specimens were collected in 1929 by W. Bliss from Pits A, B and C after the official LACM excavation ended. The age of ‘Bliss 29” insects is questionable due to un- known locality and possible contamination. Pierce’s ‘‘Pit X’’ consisted of ‘‘mixed material lacking data”’ (Pierce 1954), and may not be fossil. We have also seen silphids from UCMP loc. 2051, a large excavation made in 1912 (Stoner 1913).
Pit 91, partially excavated in 1915, was reopened in 1969 by the Rancho La Brea Project of LACM. The current excavation is laid out on the basis of 3 foot square (~.8 Square metre) grids, normally excavated in 6 inch (~15 cm) layers (each assigned a grid number), within a coordinate system, lettered from south to magnetic north and numbered from east to west. Once separated from the surrounding matrix (G. Miller 1971), the insects are cleaned with 1,1,1-trichloroethane {other solvents such as xylene may also be used) in ultrasonic cleaners. Each insect fragment (or conspecific speci- mens with the same data) is assigned an RLP entomology catalog number and is stored dry in a gelatin capsule housed in a glass vial.
Due to the enormous quantity of fossil insects recovered and the limited support available for processing them, most of the Pit 91 insects are not available for study at present. Thus, our treatment of Pit 91 silphids is only preliminary, and we hope to continue our research. We have specimens from 13 grids in 7 columns in the northeast corner of the excavation, as follows: column G-3: grid GJM 360 (5'4” to 7’ BD): J-6: GJM 346 (8'8" to 9'6” BD); L-4: GJM 408 (6’ to 6’6"” BD), GJM 612 (7' to 76” BD), GJM 856 (7'6" to 8’ BD); L-5: GJM 364 (5'4” to 5'10” BD), GJM 568 (6’4” to 7’ BD): M-3: GJM 275 (5' to 5'334” BD), GJM 295 (5'334” to 6’3” BD), GJM 550 (7’ to 7’6” BD); M- 4: GJM 777 (7' to 7'6" BD); and N-3: GJM 273 (5S’ to 6'9'4" BD), GJM 838 (8'6" to 9’ BD). These grids range in depth from 5 to 9% feet BD, with most between 6 and 8 feet BD. Two radiocarbon dates from the northeast corner of the excavation can be ap- proximately correlated with the silphids. The dates, both from bone collagen of Smi- lodon californicus Bovard, are (Berger and Libby, in press): 30 800 + 600 radiocarbon years B.P. from 6'34” to 71” BD in column L-5 (UCLA-1718) and 32 600 + approxi- mately 2800 radiocarbon years B.P. from 7/2" to 7'6” BD in columns M-3 + 4(UCLA- 1738D). These dates and others (L. F. Marcus, personal communication) from else- where in Pit 91 indicate that most of our silphids are probably ~30 000 radiocarbon years old. Higher grids (GJM 273, 275, 295) should be younger and the deeper grids (especially GJM 838) older. The silphid-bearing deposit in the northeast corner was generally a productive deposit for vertebrates (mostly small) that terminated at a depth of ~8 feet 6 inches [2.59 m] (A. Tejada-Flores, personal communication). Silphids may be present in other sectors of Pit 91, in material which has not yet been sorted.
McKITTRICK
The McKittrick asphalt deposit is ~0.8 km south of McKittrick, Kern County, in the southern San Joaquin Valley. The biota is considered late Pleistocene, although there is some “‘admixture of a later (Recent, but not present-day) assemblage’? (DeMay 1941a:59). Berger and Libby (1966:492) dated the flora reported by Mason (1944) at 38 000 + 2500 radiocarbon years B.P. (UCLA-728) based on UCMP plant material which lacked specific excavation data (D. I. Axelrod, personal communication). How- ever, the age of Pierce’s material is questionable and it may be subfossil.
The described fossil localities are all in the NE%4 of the NE'4 of Section 29, Township 30 South, Range 22 East (Mount Diablo base line and meridian). The original 1921 excavation (UCMP loc. 4096) was on the southeast side of the present northern
88
fork of State Highway 58, but the 1925-1927 excavations (UCMP loc. 7139 and CIT VP loc. 138 = LACMIP loc. 5103) were across that road on the southeast side. The CIT VP loc. 138 ‘‘comprises essentially the same area as U.C. locality 7139” (Schultz 1938:130). Pierce’s sites 3 and 4 (LACMIP loc. 260) were southeast of the original localities, on the east side of the present State Highway 33 about 1.2 km south of McKittrick. In 1945, Pierce excavated matrix from a depth of 2 feet (~.6 metres) below the surface in a fracture in the recently exposed bank, designating this “‘site 3”’ (Pierce 1947b and unpublished notes). In 1947, Leonard Bessom of LACM collected from a depth of 4 feet (~1.2 m) near site 3. Pierce designated Bessom’s locality “‘site 4,"° and wrote that the 2 foot (~.6 m) depth at site 3 would correspond to the 24 to 30 inch (.6—.76 m) layer at site 4. Pierce believed site 3 was younger than site 4, and that the insects from site 3 indicated drier conditions than those from site 4. Stratigraphic and age relationships of Pierce’s localities to the CIT and UCMP localities have not been determined, but Pierce’s localities appear to be much younger.
CARPINTERIA
The Carpinteria asphalt deposit is located on a seaside bluff overlooking the Pacific Ocean ~1.5 km southeast of Carpinteria, Santa Barbara County, California. Fossils were discovered in the Carpinteria asphalt quarry in February 1927, and paleontological excavations were undertaken by the SBMNH, CIT and UCMP (CIT VP loc. 139 = LACMIP loc. 5102). The quarrying operation was later abandoned and the site was used as a refuse dump beginning in the 1940s. Natural topography at the site has been so drastically changed by human activities that the locations and depths of the fossil excavations can only be approximated.
The deposit is situated in a raised marine terrace of beach sands, considered middle to late Pleistocene in age (R. S. Gray, personal communication), that discon- formably overlie shales of the Monterey Formation of Miocene age. However, the terrestrial fossil-bearing zone (not to be confused with the underlying marine zone of Grant and Strong 1934), which apparently graded into the beach sands, is considered late Pleistocene in age. Two cones of Pinus radiata Don, which were among the first fossils collected at the site in early 1927, yielded dates =44 500 (QC-468), >41 000 and >53 000 (QC-467B) radiocarbon years B.P. The differences in the maximum ages of the 2 portions of QC-467B are due to differences in the statistics of separate counting in different vials (R. R. Pardi, personal communication). Asphalt-impregnated wood col- lected in 1962 from a roadcut in the asphaltic sands near the original fossil sites yielded dates >38 000 radiocarbon years B.P. (UCLA-180 and UCLA-181 in Fergusson and Libby 1964), but their stratigraphic relationship to the original excavations is unknown.
SYNOPSIS OF CALIFORNIA SILPHIDAE
Family Silphidae? Tribe Pterolomini Genus Apteroloma Hatch 1927
These small beetles (length 5-7 mm) are found under stones and debris, especially at stream margins. We are giving Apteroloma generic status rather than subgeneric status under Pteroloma Gyllenhal 1827 in accordance with studies by R. B. Madge and A. F. Newton. Papers by Van Dyke (1928), Hatch (1957), and Bolivar y Pieltain and Hendrichs (1972) are useful for identification of species. The genus has no known fossil record in California.
2 According to a study in preparation by A. F. Newton, the tribes Pterolomini and Agyrtini should be removed from the Silphidae and combined into a distinct family. Awaiting this change, we will follow the traditional inclusion of these tribes in the Silphidae.
89
Apteroloma caraboides (Fall)
Pteroloma caraboides Fall 1907:235 Apteroloma caraboides of Hatch 1928:70 Pteroloma (Apteroloma) caraboides of Hatch 1957:6
Ranges from British Columbia and Idaho to northern California. Only one speci- men (a syntype) is known from southern California: Mount San Antonio [=**Old Baldy’’|, 9000 feet [~2740 m], 19 June 1904 (C. A. Richmond:MCZ).
Apteroloma tenuicorne (LeConte)
Necrophilus tenuicornis LeConte 1859a:84 Pteroloma tenuicorne of Horn 1880:245
Apteroloma tenuicorne of Hatch 1927b:12 Pteroloma (Apteroloma) tenuicorne of Hatch 1957:6
Ranges from British Columbia, Montana and Colorado to northern California. Only one specimen is known from southern California: Mill Creek, San Bernardino Mountains, 4800 feet [~1460 m], 15 April 1965 (CDA).
Apteroloma tahoecum (Fall)
Pteroloma tahoeca Fall 1927:136 Apteroloma tahoeca of Hatch 1928:70 Pteroloma (Apteroloma) tahoeca of Hatch 1957:6
Found primarily in the Sierra Nevada Mountains, but also in other areas of north- ern California and Oregon. Several old and questionable records exist for Nevada and Utah.
Tribe Agyrtini Genus Pelatines Cockerell 1906
The following is the first record of the genus in California; it has no known fossil record in the state.
Pelatines latus (Mannerheim)
Necrophilus latus Mannerheim 1852:331 Pelates latus of Horn 1880:244 Pelatines latus of Cockerell 1906:240
This small (3—4 mm long) species ranges from southeastern Alaska to northern California. In California, it is known from Alameda, Del Norte and El Dorado counties (specimens in ANSP, CDA, CMNH, and MCZ).
Genus Agyrtes Froelich 1799
The small (length 3—S mm) and little known North American species of Agyrtes were reviewed by Peck (1975). The genus has no known fossil record in California.
Agyrtes longulus (LeConte)
Necrophilus longulus LeConte 1859b:282 Agyrtes longulus of Horn 1880:246
Ranges from central California northwards through coastal mountains to southern Alaska and inland to Idaho, presumably associated with forest habitats.
90
Agyrtes similis Fall Agyrtes similis Fall 1937:29
Known only from a few specimens from the coastal ranges of central and southern California.
Genus Necrophilus Latreille 1829 Necrophilus hydrophiloides Mannerheim
Necrophilus hydrophiloides Mannerheim 1843:253
Adults (length 9-11 mm) and larvae are found on carrion and decomposing veg- etable matter from southeastern Alaska to southern California (extension of published range south into Los Angeles County). The species has no known fossil record in California.
Tribe Silphini Genus Aclypea Reitter 1885
We are using Acl/ypea as it was used by Seidlitz (1888:311), whom we regard as the first reviser in accordance with article 24(a)(i) of the International Code of Zoolog- ical Nomenclature. These species have often been placed in Blitophaga Reitter 1885. The genus has no known fossil record in California.
Aclypea bituberosa (LeConte), comb. nov. Figure 1A, B
Silpha bituberosa LeConte 1859c:6
The occurrence of A. bituberosa in the Sierra Nevada Mountain region has been confused and unconfirmed since Horn’s misidentified record of Silpha opaca “‘near Mono Lake’’ (Horn 1880), based on a single specimen (now in MCZ). California oc- currence of A. bituberosa is now well documented by these additional specimens: Alpine County: Ebbetts Pass, 8 July 1970 (F. G. Andrews: CDA), Sonora Pass, 24 June 1937 (N. W. Frazier: CAS), 27 June 1951 (E. L. Silver: LACM); El Dorado County: Echo Lake (7400 feet [~2260 m]), 15 July 1933 (A. E. Michelbacher: CAS), [Mount] Tallac, July (A. Fenyes Colln.: CAS); Tuolumne County: no further data (A. Koebele Colln.: CAS); and Yosemite National Park: Mount Lyell, 7 August 1935 (E. C. Van Dyke Colln.: CAS). The species is also known from Colorado and Manitoba to Alberta and Oregon; its biology is discussed by Cooley (1917). The primarily Pale- arctic species Aclypea opaca (Linnaeus 1759), which is often confused with A. bitu- berosa, occurs in North America only in Alaska.
Genus Thanatophilus Leach 1815 Thanatophilus lapponicus (Herbst) Figure 1C
Silpha lapponica Herbst 1793:209, plate 52: Fig. 4
Thanatophilus lapponicus of Portevin 1926:33
Silpha (Thanatophilus) lapponica of Pierce 1949:59, Figs. 1, 2 (specimens LACMIP 5722-5724)
Pleistocene.—12 specimens as follows: RANCHO LA BREA: Pit A: 2 complete and 2 partial left elytra (C3b [3], C3c, C3d = LACMIP 5722 [??], C3e), *pronotal fragment; ‘Bliss 29°’: 2 complete and 2 partial right elytra (C3f = LACMIP 5723 [3], C3g = LACMIP 5724 [92], C3h, C3i); ‘Pit X’’: broken left elytron (C3a); *PitOle Grid GJM 346: complete left elytron (RLP 3366E); Grid GJM 273: elytral fragment (RLP 4040E); Grid GJM 550: broken left elytron (RLP 4041E).
Holocene.—This 11-14 mm long carrion feeder is widely distributed through Arc-
9]
eee Senne eT TT ef + 2 ae Ney
Men:
D
oI
Fic. 1. A-B, Aclypea bituberosa (Manitoba, Canada), A, habitus; B, head; C, Thanatophilus lapponicus, habitus (Colorado); D, Heterosilpha ramosa, habitus (Colorado).
tic Europe and Asia, and in North America from Alaska and Greenland to the District of Columbia, Pennsylvania, Michigan, Iowa, Kansas, New Mexico, California and northern Mexico. Thanatophilus lapponicus was recorded from Santa Rosa Island, California by Fall (1897), but we have seen no specimens (which may have been de- stroyed in the 1906 CAS fire). It occurs more commonly in arctic and arctic alpine tundra, grassland, or open woodland habitats than in heavily forested habitats.
Thanatophiliis sagax (Mannerheim), comb. nov. Silpha sagax Mannerheim 1853:173
This 9-11 mm long species is poorly known, as 7. sagax long has been considered a junior synonym of Thanatophilus trituberculatus (Kirby 1837). The distinguishing characteristics are as follows: In 7. sagax the intervals between elytral striae lack tu- bercles, but the middle elytral stria has a single broad tubercle two thirds of the way to the apex. This tubercle slightly elevates the outer stria, which continues into the posterior quarter of the elytron. In 7. trituberculatus, the outer stria terminates at the tubercle, with a small disjunct tubercle in the posterior quarter of the elytron.
Pleistocene. —Unknown from California.
Holocene.—Thanatophilus sagax ranges from northern California (Brockway, Placer County, 15 July 1941, G. S. Mansfield in CAS) through British Columbia to Alaska (Kenai Peninsula) and eastward to the Northwest Territories and Manitoba. We have seen 7. trituberculatus from only the Northwest Territories and Manitoba.
- Ge
SP MME
I yn,
Z
several peyp
ares
= ( (
Na
iN / \
Fic. 2. Male genitalia of Heterosilpha species: A, H. ramosa (Platteville, Colorado), B, H. aenescens with internal sac everted (Alameda County, California). The chord of the arc from the edge of the basal sclerotization to the paramere tips is 2.8 to 3.0 mm in H. aenescens and 3.5 to 4.0 mm in H. ramosa.
Genus Heterosilpha Portevin 1926
Two superficially similar species, Heterosilpha ramosa (Say 1823) and Heterosil- pha aenescens (Casey 1886), occur throughout most of California. Heterosilpha aenes- cens has been considered a synonym of H. ramosa (Arnett 1944, 1946). However, as stated by Hatch (1927a, 1946) and Portevin (1926), they are distinct species. Distin- guishing characters (in decreasing order of reliability) are found in the male genitalia, secondary sexual characters and color. The male genitalia (Fig. 1 A, B) are dis- tinct and offer the most reliable identification characteristics. Heterosilpha ramosa is sexually dimorphic in the elytral apex of females and in the tarsi of males, but it is nearly impossible to distinguish the sexes of H. aenescens, except by reference to the genitalia. In females of H. ramosa the apex of the elytra is pro- longed, rather than gradually rounded as in H. ramosa males and both sexes of H. aenescens. The anterior and middle tarsi of H. ramosa males are strongly dilated, but there is no such tarsal dilation in male H. aenescens. Except for minor color and tarsal differences, H. ramosa males look very similar to both sexes of H. aenescens. The external distinguishing characteristics of H. aenescens are the aeneous lustre and coarser elytral sculpture. Adults of both species are 12-15 mm long.
Heterosilpha ramosa (Say) Figures 1D, 2A
Silpha ramosa Say 1823:193 Heterosilpha ramosa of Portevin 1926:85 (as synonym, in error, of Heterosilpha cer- varia |Mannerheim 1843)).
93
Silpha (Heterosilpha) ramosa of Pierce 1949:61, Figs. 3a, 3b (specimens LACMIP 5720 [rounded tip due to breakage] and 5721)
Heterosilpha ramosa was described from a specimen collected by Thomas Nuttall on “‘the upper Missouri’ (Say 1823:193, reprinted by LeConte 1859d:123). Because of the complete loss of the Say collection (LeConte 1859d, Lindroth and Freitag 1969), we designate as neotype a male (MCZ 32444) in the LeConte collection bearing the following labels on its pin: a greenish disk; a handwritten label ‘*‘S. ramosa/Say/cer- varia/Mann.’’; and our neotype label.
It is generally accepted (Lindroth and Freitag 1969) that LeConte had the oppor- tunity to compare his specimens with those in Say’s collection, and that LeConte’s collection is the most reliable indication of Say’s concepts of his species. The greenish disk is LeConte’s locality code for the area including the upper Missouri River and its tributaries, so the type locality is unchanged. In accordance with Article 75 of the International Code of Zoological Nomenclature, this neotype designation is in the interest of stability of nomenclature, is in connection with the revisionary work nec- essary to establish the identity of the asphalt deposit fossils, and characters differen- tiating the taxa are given. Our proposed designation has been discussed with other specialists on North American Silphidae and does not arouse objections.
Pleistocene.—Pierce (1949) apparently did not consider the possibility that some of his Heterosilpha specimens may have been H. aenescens. On the basis of elytra and pronota, it is impossible to separate H. aenescens from male H. ramosa with present knowledge. At least some of Pierce’s Rancho La Brea elytra are H. ramosa, as they show female sexual dimorphism. However, H. aenescens elytra may be mixed with the male H. ramosa. Although 8 of the 11 Heterosilpha elytra from Pit 91 have broken tips, the 3 with the apex intact are rounded, so H. ramosa cannot be positively recorded from this excavation. Only future study of the morphology of Holocene Het- erosilpha and additional Heterosilpha specimens from Pit 91 will resolve this question.
Heterosilpha is represented by 20 elytra and 2 pronota. The elytra fall into 3 cate- gories: (A) female H. ramosa, (B) elytra with rounded apexes; which could be male H. ramosa or either sex of H. aenescens, and (C) elytra with broken or damaged tips which cannot be placed in the 2 former groups; the category and side (R = right, L = left) of each is noted below. RANCHO LA BREA: Pit A: CR (Cld); *Pit 9: AR (Cli); = Bliss 29°. CL (Cla = LACMIP 5720), CR (Clb), AR (Clic = LACMIP 5721); two Plea (Clie Cit) ER (Cig). CkL (Cth) Pit 91: (Grid GIMi273° BI (REP 3247E). CL (RLP 4038E), CR (RLP 4039E); Grid GJM 295: CR (RLP 3303E); Grid GJM 360: CL (RLP 3431E); Grid GJM 364: pronotum (RLP 3486E); Grid GJM 408: BR, CL (RLP 3938E); Grid GJM 568: BL (RLP 27E), pronotum (RLP 28E); Grid GJM 612: CL (RLP 3549E, associated with Felix atrox skull): Grid GJM 777: CL (RLP 1180E, associated with Smilodon californicus skull); Grid GJM 838: BR (RLP 1824E); Grid GJM 856: CR (RLP 21646).
Holocene.—Literature records of H. ramosa cannot be trusted, due to past con- fusion with H. aenescens. Heterosilpha ramosa occurs in much of western North America (including Santa Rosa, Santa Cruz, and San Miguel islands). Brewer and Bacon (1975) have treated the biology of H. ramosa in Colorado. Linsley (1942) gives additional ecological notes on H. ramosa, but these may refer to H. aenescens (we have been unable to locate voucher specimens).
Heterosilpha aenescens (Casey) Figure 2B
Silpha aenescens Casey 1886:171 Heterosilpha aenescens of Portevin 1926:85
Heterosilpha aenescens was described from an unspecified number of specimens from San Francisco, California (Casey 1886). A lectotype is hereby designated as a male in the USNM bearing the labels ‘*Cal.’’ (with black dot in middle of the **C’’),
94
Fic. 3. Pronota of Nicrophorus species: A, N. guttula (Santa Barbara, California); B, N. marginatus (New Mexico); C, N. nigrita (Santa Barbara, California); D, N. defodiens (Northwest Territories, Canada).
“CASEY /bequest/1925,’’ red type label ““TYPE USNM/48743,”’ and our lectotype label. The lectotype and 7 paralectotypes (4 males and 3 females, all with same labels as lectotype, but red type labels ‘“‘aenescens/paratype USNM/48743’’) were all ex- amined. The USNM type labels were placed on the assumed types during curation of the Casey collection at the USNM (Buchanan 1935). Casey’s locality code indicates these specimens came from ‘‘San Francisco and immediate vicinity as far south as Redwood City and Purissima.’’ Seven other specimens from **Alameda/Co. Cal.’’ and ‘Cal’? are assigned to H. aenescens in the Casey collection, but these were not con- sidered part of the type series by Buchanan and do not bear paratype labels.
Pleistocene.—As discussed above, H. aenescens may be represented by Rancho La Brea fossils, but cannot be differentiated from H. ramosa at this time.
Holocene.—Heterosilpha aenescens ranges at least from Baja California, Mexico through California into southern Oregon.
Tribe Nicrophorini Genus Nicrophorus Fabricius 1775
The proper spelling is Nicrophorus, not Necrophorus Mlliger 1798 (Herman 1964). Arnett (1944) and Madge (1958) treat the North American species, and a revision is in preparation by R. B. Madge (personal communication).
5
Fic. 4. Nicrophorus species: A-B, N. nigrita (Santa Barbara, California), A, habitus; B, head; C, N. guttula, head (Santa Barbara, California); D, N. marginatus, head (New Mexico).
Nicrophorus defodiens (Mannerheim) Figure 3D
Necrophorus defodiens Mannerheim 1846:513 Nicrophorus defodiens of Hatch 1927a:355 Nicrophorus conversator of Leech 1934:36 (misidentification)
Nicrophorus defodiens long has been confused with Nicrophorus vespilloides (Herbst 1784). Despite the work-of Leech (1937), unpublished studies by R. B. Madge indicate that N. defodiens is a distinct species.
Pleistocene. —Unknown from California.
Holocene.—This species occurs along the Pacific Coast of North America from Alaska into central California. Leech (1934) discussed its natural history, but misiden- tified the beetles as N. conversator (Walker 1866).
Nicrophorus nigrita (Mannerheim) Figures 3C, 4A, B
Necrophorus nigrita Mannerheim 1843:251
Nicrophorus investigator nigritus of Hatch 1927a:357
Nicrophorus nigrita of Arnett 1944:15
Nicrophorus investigator alpha Pierce 1949:67, fig. 13 (specimen LACMIP 3048), NEW SYNONYMY
96
This species was once considered a subspecies of N. investigator (Zetterstedt 1824), but it is specifically distinct. True N. investigator has not been recorded in California. Pierce’s N. investigator alpha is N. nigrita, which was not considered a valid species by Hatch (1927a), upon which Pierce based his work. Nicrophorus investigator alpha was described from 6 syntype pronota (LACMIP 3048-3052, 5263; C121a-f) all from Pit A, Rancho La Brea. Pierce labeled syntype LACMIP 3048 (C121d) as holotype, although it was published (Pierce 1949) as a syntype. We are hereby designating 3048 as lectotype because it was labeled as holotype by its author, it was illustrated (Pierce 1949: Fig. 13), and it is the syntype in best condition. Specimen LACMIP 3048 was mistaken by Sphon (1973) as the holotype of N. investigator lati- frons Pierce and bears a notation to that effect.
Pleistocene.—Eleven specimens as follows: RANCHO LA BREA: Pit A: LAC- MIP 3048-3052, 5263 (N. i. alpha type series); *Pit 91: Grid GJM 295: head (RLP 3339E) and pronotum fragment (RLP 4034E); Grid GJM 408: head fragment (RLP 3944E): *CARPINTERIA: pronotum fragment and right elytron fragment.
Holocene.—This distinctive large black species is the most common Nicrophorus in southern California today. It ranges along the Pacific Coast from California (including Santa Rosa, Santa Cruz, West Anacapa, Santa Barbara and San Clemente Islands) to British Columbia and inland to Nevada.
Nicrophorus marginatus (Fabricius) Figures 3B, 4D
Necrophorus marginatus Fabricius 1801:334
Nicrophorus marginatus of Hatch 1927a:360
Nicrophorus guttulus labreae Pierce 1949:63, Figs. 4-10, NEW SYNONYMY Nicrophorus mckittricki Pierce 1949:66, Fig. 11, NEW SYNONYMY Nicrophorus investigator latifrons Pierce 1949:67, Fig. 14, NEW SYNONYMY Nicrophorus obtusiscutellum Pierce 1949:67, Fig. 12, NEW SYNONYMY
Nicrophorus guttulus labreae was described from 166 syntypes from Rancho La Brea as follows: Pit A: 31 heads (LACMIP 2950, 2951, 4339, 5633-5660), 31 pronota (2953-2979, 4334, 4353, 4354, 5270), 2 right elytra (2952, 4336), left elytron (4348), 6 scutella (4337, 4341, 4343, 4345, 4351, 4352), and 8 tibia (4335, 4338, 4340, 4342, 4344, 4346, 4349, 4350); Pit B: head (4355), 2 pronota (2980, 2981); ‘Bliss 29°": 2 heads (4370, 4371), 9 pronota (4362-4369, 4374), left elytron (4372); Pit 28: pronotum (3045); Pit 37: pronotum (3046); Pit 81: 3 tibia (4357-4359), elytral fragment (4361); ‘‘Pit X°’: 34 heads (3011-3044), 28 pronota (2982-3010), left elytron (4356); unknown pit: head (4374). Syntype 4351, an elytral fragment from Pit 81, is apparently not a silphid. Syntype 2952 (C2al, a complete right elytron from Pit A) was labeled by Pierce as holotype, but this designation is invalid as the taxon was published on the basis of syntypes. We are hereby designating 2952 lectotype (Pierce 1949: Fig. 4). Unpublished notes and specimen labels indicate that Pierce first considered this a subspecies of N. marginatus, but published it under N. guttula. Nicrophorus mckittricki: was described from the holotype pronotum (LACMIP 3054 = McK3a) and 2 paratype elytra (5733 and 5734; McK3b and McK3c) from site 3, depth 2 feet [~0.6 m] at McKittrick, 6 paratype elytra (5735-5740; McK3d—McK3i) from site 4, depth 4 feet [~1.2 m] at McKittrick, and 8 ‘‘tentatively associated’? specimens (not paratypes) from Pits A, B, “XxX, 28; and ‘Bliss 29°’, Rancho La Brea (C120a—c and unnumbered). One ‘*tentatively associated” specimen has not been located, and may not be N. marginatus. Although the holotype does have characteristics that tend toward N. guttula, it is a specimen of N. margin- atus. Nicrophorus investigator latifrons was described from the holotype head (LAC- MIP 3053 = C120d) from ‘‘Pit X’’, Rancho La Brea. Nicrophorus obtusiscutellum was described from the holotype scutellum (LACMIP 3055 = C120e) from Pit A, Rancho La Brea. Although it is possible that this specimen represents a distinct taxon, there is not enough evidence to convince us at present. We consider it N. marginatus be- cause it falls within the range of variation of this species.
oi
Pleistocene.—Two hundred forty-four specimens and | literature record: RAN- CHO LA BREA: Pits A, B, 28, 37, 81, ‘‘Bliss 29’’, ‘‘Pit X’’, and an unknown pit; LACMIP 2950-3046, 4334-4359, 4361-4374, 5270, 5633-5660 (type series of N. g. labreae);, Pit A: LACMIP 3055 (holotype of N. obtusiscutellum), head, pronotum (C120a), *2 complete and 2 fragmentary pronota, *5 complete and 3 fragmentary heads, *scutellum, *6 elytral fragments (elytral determinations questionable); Pit B: head; ‘Bliss 29°°: pronotum (C120c); Pit 28: pronotum (C120b); Pit 81: *head fragment; **Pit X’’: head, *head, 3 fragmentary pronota, LACMIP 3053 (holotype of N. (. latifrons), 3 heads (1 recorded by Pierce but now missing); * Pit 91: Grid GJM 295: right and partial left elytra (RLP 3314E), 2 pronotum fragments (RLP 4035E); Grid GJM 408: pronotum fragment (RLP 3941E); *UCMP loc. 2051: 10 complete and | fragmentary heads, 13 pronota; McKITTRICK: Pierce’s Site 3, depth 2 feet: LACMIP 3054, 5733, 5734 (holotype and paratypes of N. mckittricki); Pierce’s Site 4, depth 4 feet: LACMIP 5735-5740 (paratypes of N. mckittricki); *CIT VP loc. 138: 7 heads.
Holocene.—Ranges over much of the United States and southern Canada, but is tess common in California than N. nigrita. This species seems to prefer open woodland or grassland situations to dense forests.
Nicrophorus guttula (Motschoulsky) Figures 3A, 4C
Necrophorus guttula Motschoulsky 1845:53
Nicrophorus guttulus of Hatch 1927a:359
Nicrophorus guttulus punctostriatus Pierce 1949:66, NEW SYNONYMY Nicrophorus guttulus guttulus lajollae Hatch of Pierce 1949:66
Nicrophorus guttula has been confused with N. hecate (Bland 1865), a question- ably distinct species (see below). We see no justification to consider N. g. punctostria- tus, described from holotype left elyton from Pit A, Rancho La Brea (LACMIP 3947 = C132b), a distinct subspecies.
Pleistocene.—Twenty-eight specimens as follows: RANCHO LA BREA: Pit A: LACMIP 3947 (holotype of N. g. punctostriatus), 3 elytra (C13la, C131b, C132a), *head fragment; *Pit 9: head (C2bu); ***Bliss 29°’: 1 complete and | fragmentary right elytron; *Pit 91: Grid GJM 275: head (RLP 3338E), pronotum (RLP 3101E), 3 pronotum fragments (RLP 3315E); *UCMP loc. 2051: 2 heads, pronotum;, *McKITTRICK: UCMP loc. 7139: 2 complete and 4 fragmentary elytra, 3 heads; CIT VP loc. 138: 2 heads, 1 pronotum; *CARPINTERIA: 3 heads (bearing grid notation 6B3 + 8’), left elytron.
Holocene.—The species is primarily limited to California (including San Clemente Island) and Oregon.
Nicrophorus hecate (Bland)
Necrophorus hecate Bland 1865:382 Nicrophorus guttulus hecate of Hatch 1927a:360 Nicrophorus hecate of Arnett 1944:15
Nicrophorus hecate was described from an unspecified number of specimens col- lected in the Colorado Territory by James Ridings (Bland 1865). Two specimens are placed as syntypes in the ANSP, with labels ‘‘Col.’’, **LectoTYPE/3283”’, “TY PE/ N. hecate/Bland”’ and ‘‘Col.’’, ‘‘PARATYPE/3283’’. The lectotype and paratype labels were apparently placed on the specimens in routine curation and are not valid desig- nations. We hereby designate the first, and larger, specimen lectotype.
Some populations from central California to southern Oregon show an intergra- dation of the characteristics of N. guttula into those of N. hecate. We do not presently have adequate material to document the nature of this intergradation. These are prob- ably the same species (R. B. Madge, personal communication), but we lack adequate data to formally synonymize N. hecate under N. guttula.
98
Pleistocene.—Unknown from California. Holocene.—Ranges from central California to British Columbia and east through the Rocky Mountains to the western Great Plains.
Dubious California Records
Several species have been recorded in literature or are represented in collections by specimens labeled California. Some of these represent introductions of Palearctic species which are not established in North America. Most, however, are old specimens from ‘‘California’’ which we think are mislabeled, as follows: Necrodes surinamensis (Fabricius 1775): ‘‘Cal.’> (LACM)—does not occur in California (Ratcliffe 1972); Ni- crophorus germanicus (Linnaeus 1758): ‘California’ (holotype of Necrophorus gran- dior Angell 1912; Hatch 1927a)—Palearctic; Nicrophorus humator (Gleditsch 1767): ‘‘California’’ (paratype of N. grandior; Hatch 1927a)—Palearctic; N. investigator (Zetterstedt 1824): ‘‘Cal.’? (F. C. Bowditch Collection: MCZ); Nicrophorus orbicollis (Say 1825): San Jacinto Mountains (Madge 1958), **Cal.’° (MCZ); Nicrophorus pus- tulatus (Herschel 1807): ‘‘Cal.’’ (Hatch 1927a); Nicrophorus tomentosus (Weber 1801): Trabuco Canyon, Orange County, 10 July 1963 (D. Hubbard: LACM); Oxelytrum discicolle (Brulle 1840): **Southern California’ (Hatch 1927a); Silpha tristis Iliger 1798: Santa Ana, in soil 9 March 1959 (J. L. Bath: UCR)—Palearctic.
Two species that live in adjacent regions may range into California. These are Oxelytrum discicolle (Brulle 1840) known from northern South America to northern Mexico and Thanatophilus truncatus (Say 1850), occurring from Arizona and western Mexico northward and eastward through the Rocky Mountain chain to the prairies of Colorado and Kansas.
KEY TO CALIFORNIA SILPHIDAE
ile a. Elytra with 3 longitudinal ridges or smooth; generally large beetles Cus uallliy2 UO annvann) ree oe eae ea eee eee nage aves roe oar vere Ose ce ee 8
b. Elytra with 9 longitudinal depressed lines, rarely becoming indistinct; genetallyesmall beetles: (usually, <lOimm) i220. . «arse. eee 2
2. (1) a. Antennae filiform; 7th antennal segment twice as long as wide, or INCA aS Os rycen eatin een teae tece omy eee ecenics. fnena Moa eas (Apteroloma) 3
b. Antennae clavate; 7th antennal segment nearly as wide as long.... Sse Re ON Nee eT foot Peete Perego SN auc te hanes lake te Se (Agyrtini) 5 3. (2) a. Pronotum distinctly narrowed posteriorly, much narrower at base
than base of elytra, somewhat cordate .......... Apteroloma caraboides b. Pronotum only slightly narrowed posteriorly, almost as broad at base as base or elytha, MOL. Condate= tans... iohee se cnee ats oe eee ee 4 4. (3) a. Hind angles of pronotum sharp cornered......... Apteroloma tahoecum b. Hind angles of pronotum rounded .............. Apteroloma tenuicorne
5. (2) a. Maxillary palpi with terminal segment about same width as penulti- mate segment; terminal antennal segment subequal or more than
twiceras lone as penultimate seementmr sya... ee eee 6 b. Maxillary palpi with terminal segment much wider than penultimate segment; terminal antennal segment less than twice as long as pen-
UltIMAlesSe OMEN ten nrnkenry ea crae eee wee aes cine ee eee (Agyrtes) 7 G2) aa enothisammpandvsreatenarre rss ae oe Necrophilus hydrophiloides Bebe mp tlic <eSumiin aee fone apetetes ro ete rol oy oe, eich oh teen Pelatines latus
7. (5) a. Antennal club of 4 segments; 3rd antennal segment appreciably longer than the 2nd; aedeagus in side view with a pronounced bend... sees tates piel & ph acre ents ais oes me ane yee carl iar eee | ORR Conan Rn mee Agyrtes longulus b. Antennal club of 5 segments; 3rd antennal segment only slightly long- er than the 2nd; aedeagus in side view relatively straight Agyrtes similis 8. (1) a. Elytra truncate, exposing at least tip of abdomen; general shape elon- sate (as im Bigs4A) $202 Hees aso nc ee oe ee ee (Nicrophorus) 9
9
b. Elytra covering most or all of abdomen; general shape oval (as in
Rigel Avy 1 ND) 5 tare sake aes es SES Noah cots hee ences sateen erate ee 13
9. (6) a. Pronotum (Figs. 3C, 3D) sides feebly sinuate; pronotum base nearly asawide aS apex» Pronotum not CONdALem: an outs cited kre eens) oi 10
b. Pronotum (Figs. 3A, 3B) sides strongly sinuate; pronotum base much farkowenthaneapex: pronotumecordate, ~ Sahn... ates estoiele clones eee 11
10. (9) a. Elytra black; 3 terminal segments of antennae orange; metasternal PUDESCENCE DIOWMe 2.15 Sos age. wale Oa ernie ek Nicrophorus nigrita
b. Elytra with red fascia (sometimes faint); 3 terminal segments of an- tennae black; metasternal pubescence golden... Nicrophorus defodiens
11. (9) a. Basal segment of antennal club black or orange; anterior face of procoxae with very long hairs on'basalthalt 270°... 2-5 2 eee eee 12
b. Basal segment of antennal club orange; anterior face of procoxae with only short hairs on basal half............. Nicrophorus marginatus
12. (11) a. Basal segment of antennal club black; no elytral fascia; elytral epi- pleuroneredvat MumMenS- = 52.2.4 apr). corse era Nicrophorus guttula
b. Basal segment of antennal club red; red elytral fascia present; elytral epipleuron usually predominantly red.............. Nicrophorus hecate
13. (8) a. Clypeus broadly and shallowly emarginate; eyes normal, compara- (ISI NY ETP Aes ere ere ew ns on aes, Sore ee, SAE Stes Sead Cec 14
b. Clypeus sharply and deeply emarginate (Fig. 1B); eyes comparative- Hiya tinal I Qo UBS) ie lis ope cus deneucys ek es acoce Se ones tence uae ns Aclypea bituberosa
14. (13) a. Elytral intervals with reticulate sculpturing (Fig. 1D); labrum nar- rowly emarginate; pronotum not tomentose .......... (Heterosilpha) 15
b. Elytral intervals with isolated tubercles (Fig. 1C) or smooth; labrum broadly emarginate; pronotum usually tomentose .... (Thanatophilus) 16
15. (14) a. Not sexually dimorphic, dd and 2 @ superficially alike; male geni- (EBIITEN SIS Tael B20 BR ee ene PR Re a een eee cle Heterosilpha aenescens
b. Sexually dimorphic, elytral apex of ° 2 elongated, front and middle tarsi of 66 dilated; male genitalia as in Fig. 2A .... Heterosilpha ramosa
16. (14) a. Intervals between elytral striae with 8-10 tubercles; common SWECleS ies NIC) \5. 5 1 ecory eames hacen nena Thanatophilus lapponicus
b. Intervals between elytral striae without tubercles; rare species Beane ots (NaS i Sas ad ahs Wp ae eae ote ent Rees Thanatophilus sagax
PALEOECOLOGY Silphid ecology
Silphids are found mostly on carrion and occasionally on decaying vegetation. Some feed on the carrion or plant matter, whereas others are predaceous on maggots and other animals present on the carrion. Adults of Nicrophorus species bury carrion such as mice and reptiles (Milne and Milne 1976).
Pierce (1949) considered silphids to be characteristic inhabitants of carrion in ‘‘ammoniacal fermentation’’ (his fifth period of decomposition), occurring in the 4th to 8th months following death. His conclusion, based on forensic studies of insects associated with human corpses, is excessive, as silphids inhabit carrion much sooner after death. In some cases, silphids find carrion within an hour after death (Milne and Milne 1944). Shubeck (1969) found that ‘‘Carrion seemed to be most attractive to carrion beetles from the fifth to the tenth days when it was in the fresh-bloated, bloated, and decay stages. Since this is the period of time during which the maggots were present ... , it is possible that they are in some way involved in making the carrion habitat attractive to carrion beetles.”’ Illingworth (1927), at Upland, California, found adult Nicrophorus nigrita *‘feeding on maggots”’ under a cat dead 3 days. He found Thanatophilus lapponicus under the cat after 7 days. After 27 days, **Many fat silphid larvae were present. They had destroyed a large percentage of the dipterous larvae.’ The ecology of the California silphids is poorly known, although most are large, con-
100
spicuous, and easy to attract (Newton and Peck 1975) and capture. Until such infor- mation is obtained, silphids can contribute only a fraction of their potential to an understanding of California Pleistocene paleoecology.
Accumulation and Preservation of the Fossils
The popular generalization regarding accumulation of fossils at Rancho La Brea presents a picture of great pools of continuously active liquid asphalt which trapped unwary animals, which in turn attracted scavengers which also became trapped (Stock 1956 and others). However, recent studies (Woodard and Marcus 1973) indicate that such great ‘‘death traps”’ had little role in the accumulation of fossils. Reinterpretation of stratigraphy and radiocarbon dating indicates that the fossil deposits were formed at the sites of discontinuously active asphaltic seeps during the accumulation of allu- vium from the late Pleistocene to the present. Most deposits are stratified and can be correlated with facies of surrounding sediments which are not oil impregnated. The ‘pits’? at Rancho La Brea were artifacts of excavation, and did not represent naturally occurring deep pools of liquid asphalt. Woodard and Marcus (1973) further state that ‘‘While the larger and more continuous pockets may represent areas of asphaltic quick- sand in which animals became mired, it is apparent from the abundance of coarse, stream-worn debris that many of the smaller pockets more likely represent localized fluviatile concentrations of bones in stream channels or ponds. Once buried, the abrad- ed and fragmented fossils were enveloped in asphalt permeating upwards and laterally into the sediments from active vents and fissures.’’ Penetration by asphalt was prompt in some cases, preserving fragile specimens such as leaves. Some trapping of small animals may have taken place in shallow pools of asphalt concealed by leaves, dirt or water and/or covered with a thin and weak layer of hardened asphalt.
Deposition at McKittrick was discussed by Shultz (1938): ** During late Pleistocene time sedimentation was active in the area, and as the oil reached the surface [from numerous small discontinuously active petroleum seeps] and spread out in sheets of a fraction of an inch or so in thickness it became intercalated with clay, sand, gravel, and windblown material. The resulting product is a rudely stratified material consisting of fine and coarse sediments more or less uniformly saturated with petroleum. The upper layers which contain a Recent vertebrate fauna seem to be somewhat better stratified than the lower levels which contain the Pleistocene vertebrates. Vander Hoof (1934) . . . contends that it was mainly during the summer months that the oil became fluid enough to spread over large areas; while the winter rains carried in most of the clastic material.’ The result is a brea belt representing a complicated sequence of events.
The geology of the Carpinteria asphalt deposit also indicates fluviatile deposition of the fossils (Putnam 1942). Many plant fossils (especially wood) are water worn and partially decayed, indicating stream alluvium subsequently impregnated with asphalt (Chaney and Mason 1933, Mason 1940, Webber 1933). Ralph Hoffman wrote (unpub- lished letter to R. W. Chaney, 4 June 1932) that ‘‘the steam shovel at the asphalt beds has struck a tangle of stumps and logs so dense that they had to stop work at that point .... This ‘tangle’? was probably flood debris similar to one found in Pit 91 at Rancho La Brea.
Interpretation of accumulation and preservation by asphaltic matrix is difficult, especially in light of our present poor knowledge of and problems inherent in insect paleoecology (Kenward 1976, Coope 1977). Research in progress at Rancho La Brea eventually may provide more definitive answers, but 2 distinct processes appear to be involved: direct preservation (trapping in viscous asphalt) and indirect preservation (impregnation with asphalt subsequent to death and burial). Entrapment of insects occurs in 4 ways. (1) Insects can be attracted to carrion or other material already trapped or otherwise in contact with asphalt. (2) Insects, especially aquatic species, can be attracted to pools of oil and water which appear as water, but this probably has little affect on silphids. (3) Insects can be attracted to the asphalt itself. Some insects
101
are attracted to fresh tar coating roads (Saylor 1933, Hubbs and Walker 1947), but we are not aware of any silphids being attracted to asphalt. (4) Insects can be accidentally trapped, without being attracted, by crawling, flying, or falling into asphalt and not being able to free themselves. In practice, preservation/entrapment is a product of all these processes, all of which have been observed to occur at modern asphalt seeps, but the relative importance of each process is not known. Also, some species may have been more attracted than others to the particular microhabitats present.
A special case of preservation has been observed at the Maricopa deposit. At this site, asphaltic outcroppings occur in large mounds which are often penetrated by large cracks and rodent burrows. Tenebrionid beetles (Coleoptera: Tenebrionidae) often live in and about these orifices, and their remains, apparently only several seasons old, are found along with seeds and other debris in low points in these holes. Although not presently impregnated with asphalt, future changes in the activity of the asphalt could easily mix this Holocene material into surrounding Pleistocene matrix. This should especially be considered when evaluating Pierce’s McKittrick fossils. These cracks may also be responsible for movement of fossils within the deposit (similar to a Ver- tisol, see Johnson and Hester 1972).
Late Pleistocene Environmenis
At Rancho La Brea, several apparently contemporaneous late Pleistocene plant communities existed in the vicinity of the site of deposition now known as Pit 91 (Warter 1976). A cool, moist coastal closed-cone pine forest was probably dominant near the site, whereas chapparal and foothill woodland occurred inland on warmer, drier sites at higher elevations. Stream-drifted wood of Sequoia sempervirens (D. Don) Endlicher suggests the occurrence of coast redwood forest in sheltered canyons in nearby mountain foothills. Riparian woodland and aquatic plants are also represented from Pit 91, as are herbs from drier situations. Plants recovered from the silphid- bearing grids indicate the presence of nearby standing water at the time of preservation (J. K. Warter, personal communication). Thus, the silphids were apparently deposited in a placid pool in a slow stream or a pond margin.
As shown by differences in faunal composition (Howard 1962, Marcus 1960, Stock 1956) and radiocarbon dates (L. F. Marcus, personal communication), the many Ran- cho La Brea “‘pits’’ are not equivalent accumulations representing the same time pe- riods and ecological conditions. Unfortunately, most of the pits from which insects are available are not among the important vertebrate-bearing pits, and have not been in- cluded in papers analyzing paleoecology, age, or vertebrate faunal composition. Also, many of the faunal differences may be attributable to selective entrapment and/or selective preservation due to differences in the physical characteristics of the individual asphalt seeps and their methods of accumulating organic material. Because of differ- ences between periods of activity of the Rancho La Brea asphalt seeps, several envi- ronments and associated biotas are represented. Thus, older conclusions about the Pleistocene environment and climate at Rancho La Brea (i.e., Stock 1956), most of which assumed that the pit faunas were contemporaneous, must be used with caution. Even more recent conclusions must be used with care due to new data from the current excavation of Pit 91. However, the general conclusions of Brattstrom (1953a) seem safe. He suggested ‘that from Late Pleistocene to Recent there was a local transition from a moist climate of Pinus and Cupressus through a stage of decreasing rainfall and a vegetation of Quercus agrifolia and Juniperus californica, to the present-day climate and vegetation of Oakwoodland Savanna and Coastal Sage-scrub with subsequent changes in the fauna.’’ Available radiocarbon dates indicate that asphalt seeps at Ran- cho La Brea have been active over most of the last 40 000 yr (Woodard and Marcus 1976). Further information on late Pleistocene climate and fauna can be found in John- son (1977b) and W. Miller (1971).
At McKittrick, the late Pleistocene climate and environment were similar to those of the region today, except that there was probably more rainfall and perhaps a nearby
102
TABLE 1. Occurrence of silphids in California Pleistocene deposits
Taxa Rancho La Brea McKittrick Carpinteria Heterosilpha ramosa xX Thanatophilus lapponicus XxX Nicrophorus nigrita xX x Nicrophorus guttula x xX x Nicrophorus marginatus x x
lake or marsh (Brattstrom 1953b, DeMay 1941a, Mason 1944, and Schultz 1938). DeMay (1941a) reconstructed the environment as **. . . sparsely timbered mountain slopes givling] way to brush-covered hills and arid or semi-arid plains lying adjacent to a desert lake.’ The flora was a pinyon-juniper woodland similar to that presently occurring in the foothills of the Sierra Madre Mountains bordering the Cuyama Valley in northeastern Santa Barbara County, about 50 km south of McKittrick (Mason 1944).
At the Carpinteria deposit, the fossil assemblage indicates that the environment in the immediate vicinity of the site was more moist than at present (Chaney and Mason 1933, DeMay 1941b, Wilson 1933). Most components of the assemblage indicate an environment similar to that now present on the Monterey Peninsula (320 km north- west), although with less oceanic influence. However, xeric components indicate the presence of a drier environment nearby, or perhaps at a different time. DeMay (19415) suggested, due to the scarcity of aquatic bird fossils, that the site was more remote from the seacliff than it presently is, and that no large body of freshwater, such as apparently was present at McKittrick, existed in the vicinity. The few studies on insects of this deposit agree with these conclusions (Lance 1946, Miller 1978, Moore and Miller 1978).
Silphid Faunal Composition
The fossil record indicates that the composition of the southern California silphid fauna during the Pleistocene differed from that of the region today, although the fossil record may not be a representative sampling of Pleistocene populations. Of the 16 Holocene California silphids, only 6 are important to the fossil study: Thanatophilus lapponicus, Heterosilpha aenescens, H. ramosa, Nicrophorus nigrita, N. guttula, and N. marginatus. Nicrophorus nigrita is the most abundant species of Nicrophorus, followed by N. guttula, with N. marginatus being found only occasionally. The habitat preferences of these species are poorly known.
The fossil record (Table 1) shows that Thanatophilus lapponicus and Heterosilpha ramosa were present in Pleistocene southern California. Heterosilpha aenescens may have been present, but cannot be distinguished from H. ramosa on the basis of elytra. Fossils of Nicrophorus marginatus are most abundant, but N. guttula and N. nigrita are also present. Pierce’s Rancho La Brea material is dominated by N. marginatus (90%), with a small percentage of N. guttula and even less N. nigrita. The UCMP loc. 2051 at Rancho La Brea yielded mostly N. marginatus (87%) with some N. guttula (13%). Overall, the current excavation of Pit 91 has produced similar numbers of N. marginatus and N. guttula with slightly fewer N. nigrita. Nicrophorus marginatus and N. guttula have not been found in the same grids in Pit 91. Grid GJM 275 yielded only N. guttula, but grids GJM 295 and GJM 408 yielded only N. marginatus and N. nigrita in almost equal numbers. At Carpinteria, only N. guttula and N. nigrita are found, with the former more abundant. At McKittrick, UCMP loc. 7139 yielded only N. guttula whereas Pierce’s sites 3 and 4 yielded only N. marginatus. The CIT VP loc. 138 yielded both N. guttula and N. marginatus, but considerably more N. marginatus. This apparent change in faunal composition could be due to (1) the inadequacy of the fossil record and/or to (2) true differences in faunal composition due to climatic shifts.
True changes in faunal composition could be due to (1) alterations in the relative abundances of populations in situ over time and/or (2) movement of new populations
103
into the region, replacing the previous populations. Such changes, initiated by the climatic shifts associated with glaciation, could have occurred multiple times during the late Pleistocene. With these climatic shifts came variations in vegetation and the kinds of carrion available, including extinction of the large mammals that were present in the region during the Pleistocene. This extinction was probably largely due to sudden climatic changes, with perhaps some influence from human hunting (Axelrod 1967, Johnson 1977a). At least some Nicrophorus species show no interest in carrion too large for them to bury (Milne and Milne 1944), so the Pleistocene Nicrophorus may not have utilized large mammal carrion. Climatic variations would have also affected the rate of decomposition of carrion, changing its insect fauna. These factors could have favored certain species over others, thus modifying the relationships of popula- tions present in the region, or they could have favored species not previously present in the region, thereby allowing new populations to displace the previous resident species. Research at Rancho La Brea, Searles Lake (Smith 1968, 1976), and other places may eventually correlate late Pleistocene climatic shifts with floral and faunal changes.
ACKNOWLEDGMENTS
We are especially indebted to Edward C. Wilson and Charles L. Hogue of LACM and F. C. Hochberg of SBMNH for support of this project and editorial assistance. Christopher A. Shaw, William A. Akersten, George T. Jefferson, and the rest of the Rancho La Brea Project staff gave generous help with Rancho La Brea specimens and information. Ronald B. Madge, of the Commonwealth Institute of Entomology % the British Museum (Natural History), provided generous help and allowed use of previously unpublished results of his extensive study of the Silphidae. Important assistance and information was given by Daniel I. Axelrod, Rainer Berger, Howard A. Bronstein, Kevin R. Cheesman, Julian P. Donahue, David K. Faulkner, Robert S. Gray, Donald L. Johnson, L. E. C. Ling, Leslie F. Marcus, Robert M. McKenzie, Charles A. Miller, Helen M. Miller, Alfred F. Newton, Philip G. Owen, Joseph H. Peck, Richard L. Reynolds, Theodore J. Spilman, Janet K. Warter, David P. Whistler and the curators of the Holocene silphid collections examined. The excavation and curation of specimens by the Rancho La Brea Project was partially funded by National Science Foundation grant GB 24819 and grants from the LACM Foundation. The continuing work on systematics, distribution, and biology of silphids and other scavenging beetles by Peck is supported by operating grants from the Canadian National Research Council. California island fieldwork by Miller was partially supported by an American Association for the Advancement of Science Grant-in-aid (through the Southern California Academy of Sciences) and the National Park Service (contract number CX-2000-8-0040).
LITERATURE CITED
Brattstrom, B. H. 1953a. The amphibians and rep-
Angel, J. W. 1912. Two new North American tiles from Rancho La Brea. Transactions of
species of Necrophorus (Coleop.). Entomolog-
ical News 23(7):307.
Arnett, R. H., Jr. 1944. A revision of the Neartic [sic] Silphini and Nicrophorini based upon the female genitalia (Coleoptera, Silphidae). Jour- nal of the New York Entomological Society $2(1):1-25.
1946. Coleoptera notes I: Silphidae. Ca- nadian Entomologist 78(7—8): 131-134.
Axelrod, D. I. 1967. Quaternary extinctions of large mammals. University of California Pub- lications in Geological Science 74: 1-42.
Berger, R., and W. F. Libby. 1966. UCLA ra- diocarbon dates V. Radiocarbon 8:467—497.
. In press. UCLA radiocarbon dates X. Radiocarbon.
Bland, J. H. B. 1865. Descriptions of several new species of North American Coleoptera. Pro- ceedings of the Entomological Society of Philadelphia 4:38 1-384.
Bolivar y Pieltain, C., and J. Hendrichs. 1972. Distribucion en Norteamerica del genero ho- lartico Pteroloma Gyllenhal, 1827 y estudio de tres nuevas formas mexicanas (Col. Silph.). Ciencia [Mexico] 27(6):207-216.
the San Diego Society of Natural History
11(14):365-392.
. 1953b. Records of Pleistocene reptiles from California. Copeia 1953(3):174-179. Brewer, J. W., and T. R. Bacon. 1975. Biology of the carrion beetle Silpha ramosa Say. Annals of the Entomological Society of America
68(5):786-790.
Buchanan, L. L. 1935. Thomas Lincoln Casey and the Casey Collection of Coleoptera. Smithsonian Miscellaneous Collections 94(3):1— 15%
Carpenter, F. M. 1968. The affinities of the genus Sobobapteron Pierce. Bulletin of the Southern California Academy of Sciences 67(4):263- 265.
Casey, T. L. 1886. Descriptive notices of North American Coleoptera. I. Bulletin of the Cali- fornia Academy of Sciences 2(6):157—264.
Chaney, R. W., and H. L. Mason. 1933. A Pleis- tocene flora from the asphalt deposits at Car- pinteria, California. Carnegie Institution of Washington, Publication 415(3):45—79.
Cockerell, T. D. A. 1906. Preoccupied generic
104
names of Coleoptera. Entomological News 17:240-244.
Cooley, R. A. 1917. The spinach carrion beetle: Silpha bituberosa Lec. Journal of Economic Entomology 10:94—102.
Coope, G. R. 1970. Interpretations of Quaternary insect fossils. Annual Review of Entomology 15:97-120.
1977. Quaternary Coleoptera as aids in the interpretation of environmental history. Pages 55-68 in Shotton, F. W., editor. British Quaternary Studies/Recent Advances. Clar- endon Press, Oxford.
DeMay, I. S. 1941a. Quaternary bird life of the McKittrick asphalt, California. Carnegie In- stitution of Washington, Publication 530(3):35— 60.
_ 1941b. Pleistocene bird life of the Carpin- teria asphalt, California. Carnegie Institution of Washington, Publication 530(4):61—-76.
Fabricius, J. C. 1801. Systema eleutheratorum se- cundum ordines, genera, species: adiectis sy- nonymis, locis, observationibus, descriptioni- bus. Kiliae: Impensis Bibliopolii Academici Novi. 2 Volumes. [reprint 1970, Vaals: Asher and Company].
Fall, H. C. 1897. A list of the Coleoptera of the southern California islands, with notes and descriptions of new species. Canadian Ento- mologist 29:233-244.
1907. New Coleoptera from the south-
west-III. Canadian Entomologist 39:235-243.
_ 1927. New Coleoptera XII. Canadian
Entomologist 59: 136-141.
1937. Miscellaneous notes and descrip- tions (Coleoptera). Canadian Entomologist 69:29-32.
Fergusson, G. J., and W. F. Libby. 1964. UCLA radiocarbon dates III. Radiocarbon 6:318-339.
Grant, U. S., and A. M. Strong. 1934. Fossil mol- lusks from [below] the vertebrate-bearing as- phalt deposits at Carpinteria, California. Bul- letin of the Southern California Academy of Sciences 33(1):7-11.
Hatch, M. H. 1927a. Studies on the Silphinae. Journal of the New York Entomological So- ciety 35:331-370.
1927b. Studies on the carrion beetles of
Minnesota, including new species. University
of Minnesota Agricultural Experiment Station
Technical Bulletin 48:1-19.
. 1928. Fam. Silphidae II. Coleopteroum
Catalogus 7(95):1-154.
. 1946. Mr. Ross H. Arnett’s **Revision of
the Nearctic Silphini and Nicrophorini.”’ Jour-
nal of the New York Entomological Society
54:99-103.
1957. The beetles of the Pacific North- west: Part II: Staphyliniformia. University of Washington Publications in Biology 16:i-ix, 1- 384.
Herbst, J. F. W. 1793. Natursystem aller befann- ten in- und auslandifchen insecten als eine fortfekung der von Buffonschen naturge- schichte. Der Kafer. Volume 5. Pauli: Berlin.
Herman, L. H., Jr. 1964. Nomenclatural consid- eration of Nicrophorus (Coleoptera: Silphi- dae). Coleopterists’ Bulletin 18(1):5-6.
Horn, G. H. 1880. Synopsis of the Silphidae of the United States with reference to the genera of other countries. Transactions of the Amer- ican Entomological Society 8:219-322.
Howard, H. 1962. A comparison of avian assem- blages from individual pits at Rancho La Brea, California. Los Angeles County Museum Con- tributions to Science 58:1-24.
Hubbs, C. L., and B. W. Walker. 1947. Abun- dance of desert animals indicated by capture in fresh road tar. Ecology 28(4):464—466.
Illingworth, J. F. 1927. Insects attracted to carrion in Southern California. Proceedings of the Hawaiian Entomological Society 6:397-401.
Johnson, D. L. 1977a. The California ice-age re- fugium and the Rancholabrean extinction problem. Quaternary Research 8:149-153.
1977b. The Late Quaternary climate of coastal California: evidence for an ice age re- fugium. Quaternary Research 8:154-179.
Johnson, D. L., and N. C. Hester. 1972. Origin of stone pavements on Pleistocene marine ter- races in California. Proceedings of the Asso- ciation of American Geographers 4:50-S3.
Kenward, H. K. 1976. Reconstructing ancient ecological conditions from insect remains; some problems and an experimental approach. Ecological Entomology 1:7-17.
Lance, J. F. 1946. Fossil arthropods of California. 9. Evidence of termites in the Pleistocene as- phalt of Carpinteria, California. Bulletin of the Southern California Academy of Sciences 45(1):21-27.
LeConte, J. L. 1854. Synopsis of the Silphales of America, north of Mexico. Proceedings of the Academy of Natural Sciences of Philadelphia 6: 274-287.
1859a. Catalogue of the Coleoptera of
Fort Tejon, California. Proceedings of the
Academy of Natural Sciences of Philadelphia.
pages 69-90.
. 1859b. Additions to the Coleopterous fau-
na of Northern California and Oregon. Pro-
ceedings of the Academy of Natural Sciences
of Philadelphia. pages 281-293.
1859c. The Coleoptera of Kansas and
Eastern New Mexico. Smithsonian Contribu-
tions to Knowledge 11(6):1-66 + 3 plates.
_ editor. 1859d. The complete writings of Thomas Say on the entomology of North America. S. E. Cassino and Company, Bos- ton. Two volumes, xxiv + 412 pp. + 54 plates and iv + 814 pp.
Leech, H. B. 1934. The family history of Nicro- phorus conversator Walker. Proceedings of the Entomological Society of British Columbia 31:36—40.
1937. Notes on certain names in use in the vespilloides group of Nicrophorus Fab. (Coleoptera: Silphidae). Bulletin of the Brook- lyn Entomological Society 32(4):156—159.
Lindroth, C. H., and R. Freitag. 1969. North American ground-beetles (Coleoptera, Carab- idae, excluding Cicindelinae) described by Thomas Say: designation of lectotypes and neotypes. Psyche 76(3):326-361.
Linsley, E. G. 1942. Notes on the habits of some beetles from the vicinity of Yosemite National
Park. Bulletin of the Southern California Academy of Sciences 41(3): 164-166.
Macdonald, J. R. 1967. The Maricopa brea. Los Angeles County Museum of Natural History Quarterly 6(2):21-24.
Madge, R. B. 1958. A taxonomic study of the ge- nus Necrophorus in America north of Mexico (Coleoptera, Silphidae). Master's thesis. Uni- versity of Illinois, Urbana.
Mannerheim, C. G. 1843. Beitrag zur kaefer-fauna der aleutischen inseln, der insel sitkha und new-californiens. Bulletin de la Societe Im- periale des Naturalistes de Moscou 16(2):175— 314.
. 1846. Nachtrag zur kaefer-fauna der aleu-
tischen inseln und der insel sitkha. Bulletin de
la Societe Imperiale des Naturalistes de Mos- cou 19:501-S16.
1852. Zweiter nachtrag zur kaefer-fauna
der Nord-Amerikanischen laender des rus-
sischen reiches. Bulletin de la Societe Impe-
riale des Naturalistes de Moscou 25(I):283-
387.
1853. Dritter nachtrag zur kaefer-fauna der Nord-Amerikanischen laender des russi- schen reiches. Bulletin de la Societe Imperiale des Naturalistes de Moscou 26:95-273.
Marcus, L. F. 1960. A census of the abundant large Pleistocene mammals from Rancho La Brea. Los Angeles County Museum Contri- butions to Science 38:1-11.
Mason, H. L. 1940. A Pleistocene record of Pseu- dotsuga macrocarpa. Madrono 5:233-235. 1944. A Pleistocene flora from the Mc- Kittrick asphalt deposits of California. Pro- ceedings of the California Academy of Sci-
ences (series 4) 25(8):221—234.
Matthews, E. G., and G. Halffter. 1968. New data on American Copris with discussion of a fossil species (Coleopt., Scarab.). Ciencia [Mexico] 26(4): 147-162.
Matthews, J. V., Jr. 1977. Tertiary Coleoptera fossils from the North American arctic. Co- leopterists’ Bulletin 31(4):297-308.
Miller, G. J. 1971. Some new and improved meth- ods for recovering and preparing fossils as de- veloped on the Rancho La Brea Project. Cu- rator 14(4):293-307.
Miller, S. E. 1978. A fossil of Scaphinotus inter- ruptus from the Pleistocene Carpinteria as- phalt deposit, Santa Barbara County, Califor- nia (Coleoptera, Carabidae). Pan-Pacific Entomologist 54(1):74-75.
Miller, W. E. 1971. Pleistocene vertebrates of the Los Angeles basin and vicinity (exclusive of Rancho La Brea). Natural History Museum of Los Angeles County Science Bulletin 10:1- 124.
Milne, L. J., and M. J. Milne. 1944. Notes on the behavior of burying beetles (Nicrophorus spp.). Journal of the New York Entomological Society 52:311-327.
. 1976. The social behavior of burying bee- tles. Scientific American 235(2): 84-89.
Moore, I., and S. E. Miller. 1978. Fossil rove bee- tles from Pleistocene California asphalt depos- its (Coleoptera: Staphylinidae). Coleopter- ists’ Bulletin 32(1):37-39.
105
Motschoulsky, V. de. 1845. Remarques sur la col- lection de Coleopteres Russes. Bulletin de la Societe Imperiale des Naturalistes de Moscou 18(1): 1-127.
Newton, A. F., Jr. and S. B. Peck. 1975. Baited pitfall traps for beetles. Coleopterists’ Bulletin 29(1):45—46.
Peck, S. B. 1975. A review of the Agyrtes (Sil- phidae) of North America. Psyche 81(3- 4):501—-506 (°° 1974").
Pierce, W. D. 1946. Fossil arthropods of Califor- nia. 10. Exploring the minute world of the Cal- ifornia asphalt deposits. Bulletin of the South- ern California Academy of Sciences 45(3):113- 118.
. 1947a. Fossil arthropods of California. 13.
A progress report on the Rancho La Brea as-
phaltum studies. Bulletin of the Southern Cal-
ifornia Academy of Sciences 46(3):136-138.
. 1947b. Fossil arthropods of California. 14.
A progress report on the McKittrick asphalt
field. Bulletin of the Southern California Acad-
emy of Sciences 46(3): 138-143.
. 1949. Fossil arthropods of California. 17.
The silphid burying beetles in the asphalt de-
posits. Bulletin of the Southern California
Academy of Sciences 48(2):55—70.
. 1954. Fossil arthropods of California. No.
18. The Tenebrionidae-Tentyriinae of the as-
phalt deposits. Bulletin of the Southern Cali-
fornia Academy of Sciences 53(1):35—45.
. 1961. The growing importance of paleoen- tomology. Proceedings of the Entomological Society of Washington 63(3):211-217.
Portevin, G. 1926. Les grands Necrophages du globe. Encyclopedie Entomologique 6:1-—270.
Putnam, W. C. 1942. Geomorphology of the Ven- tura Region, California. Bulletin of the Geo- logical Society of America 53:691—-754.
Ratcliffe, B. C. 1972. The natural history of Nec- rodes surinamensis (Fabr.) (Coleoptera: Sil- phidae). Transactions of the American Ento- mological Society 98:359-410.
Say, T. 1823. Descriptions of coleopterous insects collected in the late expedition to the Rocky Mountains, performed by order of Mr. Cal- houn, Secretary of War, under the command of Major Long. Journal of the Academy of Natural Sciences of Philadelphia 3:139-216 [reprinted in LeConte 1883].
Saylor, L. W. 1933. Attraction of beetles to tar. Pan-Pacific Entomologist 9(4): 182.
Schultz, J. R. 1938. A Late Quaternary mammal fauna from the tar seeps of McKittrick, Cali- fornia. Carnegie Institution of Washington, Publication 487(4):111-215.
Seidlitz, G. 1887-1891. Fauna Baltica. Die Kafer (Coleoptera) der Deutschen Ostseeprovinzen Russlands. Zweite neu bearbeitete Auflage. Konigsberg: Hartungsche Verlagsdruckerei. (Silphidae issued in 1888.)
Shubeck, P. P. 1969. Ecological studies of carrion beetles in Hutcheson Memorial Forest. Jour- nal of the New York Entomological Society 77(3): 138-151.
Smith, G. I. 1968. Late-Quaternary geologic and climatic history of Searles Lake, southeastern California. Proceedings, VII Congress of the
106
International Association for Quaternary Re-
search 8:293-310.
1976. Paleoclimatic record in the upper Quaternary sediments of Searles Lake, Cali- fornia, USA. Pages 577-604 in Horie, S., ed- itor. Paleolimnology of Lake Biwa and the Japanese Pleistocene, volume 4. University of Kyoto, Kyoto, Japan.
Sphon, G. G. 1973. Additional type specimens of fossil Invertebrata in the collections of the Natural History Museum of Los Angeles County. Natural History Museum of Los An- geles County Contributions to Science 250:1- We
Stock, C. 1956. Rancho La Brea: a record of Pleistocene life in California. Natural History Museum of Los Angeles County Science Se- ries 20:1-81.
Stoner, R. C. 1913. Recent observations on the mode of accumulation of the Pleistocene bone deposits of Rancho La Brea. University of California Publications, Bulletin of the De- partment of Geology 7(20):387-396.
Vander Hoof, V. L. 1934. Seasonal banding in an asphalt deposit at McKittrick. Proceedings of the Geological Society of America, page 332.
Van Dyke, E. C. 1928. The American species of
Pteroloma (Coleoptera-Silphidae) and a new Japanese species. Bulletin of the Brooklyn Entomological Society 23(1):19-27.
Warter, J. K. 1976. Late Pleistocene plant com- munities—evidence from the Rancho La Brea tar pits. Pages 32-39 in Latting, J., editor. Plant communities of southern California. Cal- ifornia Native Plant Society Special Publica- tion No. 2, Berkeley.
Webber, I. E. 1933. Wood in the Carpinteria de- posits. Pages 66-69 in R. W. Chaney and H. L. Mason. A Pleistocene flora from the as- phalt deposits at Carpinteria, California. Car- negie Institution of Washington, Publication 415(3):45-79.
Wilson, R. W. 1933. Pleistocene mammalian fau- na from the Carpinteria asphalt. Carnegie In- stitution of Washington, Publication 440(6):59- 76.
Woodard, G. D., and L. F. Marcus. 1973. Rancho La Brea fossil deposits: a re-evaluation from stratigraphic and geological evidence. Journal of Paleontology 47(1):54-69.
. 1976. Reliability of Late Pleistocene cor-
relation using C-14 dating: Baldwin Hills—
Rancho La Brea, Los Angeles, California.
Journal of Paleontology 50(1):128-132.
Miller: Santa Barbara Museum of Natural History, 2559 Puesta Del Sol Road, Santa Barbara, California 93105, USA; and Peck: Department of Biology, Carleton Univer-
sity, Ottawa, Ontario KIS 5B6, Canada.
TRANSACTIONS
° OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 9 pp. 107-120 8 November 1979
Worms of the Mississippian Bear Gulch Limestone of central Montana, USA
Frederick R. Schram
Abstract. A fauna of worm body fossils representing the phyla Nemertina, Nematoda, and An- nelida (some with scolecodonts in place) is described from the Bear Gulch Limestone, uppermost Mississippian (Namurian), of central Montana. Many of the Bear Gulch worms have taxonomic affin- ities with worm fossils from the Mazon Creek Essex fauna, Upper Pennsylvanian, of Illinois. Some comments on possible paleoecology of Late Paleozoic worms is offered.
INTRODUCTION
Intact body fossils of worms are rare. The Burgess Shale in the Middle Cambrian of British Columbia has an extensive worm assemblage, originally described by Walcott (1911) and most recently restudied in part by Whittington (1975) and Conway Morris (1977a, 1977b). Stgrmer (1963) described some Lower Carboniferous nematodes. Schram (1973) described a nemertine and pseudocoelomates from the Upper Pennsyl- vanian Mazon Creek Essex fauna of IIlinois, and Thompson and Johnson (1977), Jones and Thompson (1977), and Thompson (1979) described various coelomate worms from Mazon Creek. The only other fossil nematodes are Tertiary in age and found in amber in association with insects and pieces of arthropod cuticle (Taylor, 1935; Dollfus, 1950). Ehlers (1868) named a eunicid polychaete from the Middle Jurassic Solenhofen Lime- stone. Polychaetous annelids have been known from the fossil record as scolecodonts, but associated jaw apparatuses are rare (Kielan-Jawarowska, 1966).
Melton (1971) called attention to the unusually preserved fauna of the Mississip- pian Bear Gulch Limestone as collected from several outcrops in Fergus County, near Beckett, Montana. The fauna contains bony fish (Melton, 1969) and Chondrichthyes (Lund, 1974, 1977a, 1977b; Lund and Zangerl, 1974), a number of invertebrates in- cluding conodont animals (Melton and Scott, 1972; Scott, 1973), and various “‘articulate groups’ of which the Crustacea are the most prominent (Schram and Horner, 1978). The fauna is of unusual preservation such that soft bodied animals as well as shell fossils are found in abundance, many of the former representing the worm phyla Nem- ertina, Nematoda, and Annelida. The worm fossils are preserved as external molds of the body, casts, actual organic remains, and color differences in the rock. This paper described the worm fauna of the Bear Gulch Limestone.
Prefixes to numbers denote specimens from the following collections: UM—Un1- versity of Montana, Missoula, CM—Carnegie Museum of Natural History, Pittsburgh, Pennsylvania.
DISCUSSION
The Bear Gulch worms are the second complete fauna of such forms to be de- scribed from the Carboniferous. The worms as a whole bear a striking resemblance to the worms of the Middle Pennsylvanian Essex fauna. Schram (1973) described the nemertine and pseudocoelomates of the Essex fauna, and Bear Gulch has specimens
108
TABLE 1. Relative abundance of worms in the Bear Gulch fauna.
Taxa Specimens (N) Worm species (%) Nemertina Archisymplectes rhothon 4 5.4 Nematoda Nemavermes mackeei 15 27.0 Annelida Phyllodocida Goniadidae Carbosesostris megaliphagon 7 7 Nephtyidae Astreptoscolex anasillosus 3 5.4 Eunicida Lumbrinereidae Phiops aciculorum 4 VP Order and family uncertain Soris labiosus 2 3.6 Ramesses magnus 6 10.9
Phylum uncertain
Deuteronectanebos papillorum 5 9 Unassignable worms 10 18
en
assignable to some of those Essex genera and species, viz., Archisymplectes rhothon and Nemavermes mackeei. Thompson and Johnson (1977) described the eunicid poly- chaete Esconites zelus, which corresponds to Phiops aciculorum at Bear Gulch. Among the 17 species of annelids mentioned by Thompson (1979), one, Astreptoscolex anasillosus, is apparently found in both faunas, and another, Pieckonia helenae, 1s closely paralleled by Carbosesostris megaliphagon at Bear Gulch. Two Bear Gulch species, Soris labiosus and Rameses magnus, do not appear to have any ready coun- terparts in the Mazon Creek Essex annelids described by Thompson. Although much of the Bear Gulch worm fauna (Table 1) is matched by virtually identical or similar forms in the Mazon Creek Essex fauna, the Essex worm fauna is much more diverse, especially in regard to polychaetes. ;
The mode of preservation between the two assemblages is different as well. The Mazon Creek material is preserved in iron carbonate concretions with superb detail of preservation. For example, Schram (1973) reported cuticular and subcuticular struc- tures in Priapulites konecniorum, Thompson and Johnson (1977) recorded gills in Es- conites zelus, and Thompson (1979) was able to observe detailed setal and acicular structure. The Bear Gulch material is preserved in a fine-grained grey to brown lime- stone. Preservation in the Bear Gulch Limestone of structures such as jaw apparatuses is equivalent to that of Mazon Creek, but details of purely soft anatomy are not quite as good as that latter fauna. For example, gills, setae, and paropodial details were not observed on the Bear Gulch material.
The correspondence of Bear Gulch worms to Mazon Creek Essex worms remains a striking one, however, and reinforces the similarity between the crustaceans of the two faunas already noted by Schram and Horner (1978). Schram (1979) suggested a nearshore marine chronofauna of invertebrates persisting through most of the Carbon- iferous of Laurentia. The Bear Gulch fauna roughly marks a midpoint in the range of the chronofauna.
The Bear Gulch worms confirm only some of the paleoecological observations of Thompson (1979) on the Mazon Creek polychaetes (Table 2). First, she commented on the generally ‘‘large’’ size of Mazon Creek polychaetes and this appears to be true for the Bear Gulch forms as well. Second, she documented the predominance of epi- faunal predaceous types in the worm assemblage. In the Mazon Creek Essex fauna 59% of the species and 54% of the individuals were epifaunal, and 76% of the species
109
TABLE 2. Habitat and feeding type of Bear Gulch worms.
Taxa Habitat Feeding type Archisymplectes rhothon epifaunal predator Nemavermes mackeei epifaunal predator Astreptoscolex anasillosus epifaunal predator Carbosesostris megaliphagon infaunal predator
Phiops aciculorum ? predator Soris labiosus ? ? Ramesses magnus 2 ? Deuteronectanebos papillorum 2 ?
and 96% of the individuals were predator-scavenger types. The Bear Gulch worm fauna is not as diverse as the Essex fauna and some species are difficult to assign to habitat and feeding type, but the importance of epifaunal habit (Table 3) and predominance of predaceous life style (Table 4) is generally upheld.
Thompson compared her fossil biotas with similar data derived from Parker (1956) on Mississippi delta polychaetes, where 61% of the species were predaceous, and from Day et al. (1971) on the North Carolina coast, where 29% of individuals were preda- ceous. Thompson’s comparisons are of limited value, however, because they deal with contemporary temperate faunas (not all deltaic), whereas contemporary tropical deltaic faunas would have perhaps been more appropriate. Parker (1956) actually deals with species from 7 distinct environments of varying sediment types collected from 280 biological stations and 130 geological cores.
Thompson concluded that the epifaunal predominance in the Essex fauna was due to the large influx of migrating adult forms (epifauna) into a small area. This area had limited access to the open sea with freshwater inflow causing salinity fluctuations. She postulates such conditions did not favor survival of migrating larval types. The issue of predator dominance is left fallow by Thompson. But current understanding of re- gional Mazon Creek paleogeography (Shabica, 1979; Baird, 1979) would not seem to bear out her migrating-adult explanation. Nor is such an explanation perhaps applicable to Bear Gulch. Furthermore, the migratory abilities of adult errantians is limited, dis- persal in all polychaetes being generally achieved by larvae. Nor do salinity fluctuations act as real long-term barriers to many polychaete forms, because Oglesby (1969) points out that all polychaetes and sipunculids investigated are osmotic conformers or develop physiologic adaptations to handle changing salt balance. Smith (1955) pointed out that at least for Nereis diversicolor, ability to spread into fresher water was more related to the length of the larval stages of a particular population rather than salinity intol- erance. Thus Thompson’s explanation for peculiarities in the nature of Mazon Creek polychaete assemblage is perhaps needlessly complicated and not in accord with what we know about living polychaete biology.
There still remains the problem of explaining the dominance of epifaunal predator- scavenger worms in these faunas. The fact that this is so for both Mazon Creek and Bear Gulch suggests that perhaps this was a distinctive yet normal feature of the Carboniferous nearshore marine chronofauna of Laurentia. Any attempt to use pres- ervational anomalies to explain this dominance must remain weak because both sites are Konservat-Lagerstatten (Seilacher, 1970). The circumstances of burial and fossil- ization mitigated to preserve the entire autochthonous fauna of those times and places
TABLE 3. Breakdown of habitat preferences of Bear Gulch worms.
Habitat Species (%) Specimens (%) Epifaunal BiED 38.2 Infaunal 255) od
Unknown 50.0 49.1
110
TABLE 4. Breakdown of feeding type preferences of Bear Gulch worms. Feeding types taken from Thompson (1979) and included for comparison.
Feeding type Species (%) Specimens (%)
Predator 62.5 $8.2 Selective deposit feeder : 383 Nonselective deposit feeder
Suspension feeder aoe ste Unknown Ss5) 41.8
essentially intact. Thus the species of worms and their relative proportions in the biotas of these localities are probably fairly close to those of the original state.
The answer as to why this peculiar epifaunal predator-scavenger dominance ex- isted in the Carboniferous nearshore marine chronofauna lies with further study and more complete understanding of the early history and origin of the nearshore marine chronofauna in the Late Devonian—Early Carboniferous. Certainly the chronofauna as such does not lack for epi- and infaunal suspension and deposit feeders. The Bear Gulch fauna has, besides some crustaceans of these types (Schram and Horner, 1978), brachiopods, pelecypods, and sponges (these last at least in the lowermost beds of the Bear Gulch Limestone). The more diverse Mazon Creek fauna has pelecypods, inar- ticulate brachiopods, a problematic hemichordate Etacystis communis (Nitecki and Schram, 1976), as well as some filter feeding crustaceans (Schram, 1979). These would have effectively augmented those few epi- and infaunal suspension and deposit feeding annelids Thompson (1979) did note.
The evidence of the overall faunal constitution and preservational nature seems to indicate that the predominance of epifaunal predaceous-scavengers in the worm contingent of the Laurentian Carboniferous nearshore marine chronofauna is a real one, distinctive to that period of time and related to the circumstances existing then.
SYSTEMATIC PALEONTOLOGY
Phylum Nemertina Genus Archisymplectes Schram, 1973 Type species Archisymplectes rhothon Schram, 1973 Archisymplectes rhothon Schram, 1973 Fig. 1b
Material.—UM 5546, 6485; CM 33941, 33942.
Remarks.—These specimens preserve the familiar twisted and knotted an SO characteristic of ‘‘ribbon worms”’ (Fig. 1b). As in the Mazon Creek Essex fauna species, A. rhothon, very little external anatomy is preserved on so relatively simple an animal as a nemertine. Conway Morris (1977a) agrees, however, that A. rhothon is probably a nemertine. Consequently, there is really very little to distinguish these Bear Gulch forms from those of Illinois, and the Montana specimens are placed in the same species of the latter. (Modern nemertine taxonomy is based on histology of the body wall and brain location, information not available in fossils.)
Phylum Nematoda Genus Nemavermes Schram, 1973 Type species Nemavermes mackeei Schram, 1973 Nemavermes mackeei Schram, 1973 Fig. la
Material.—UM 5554, 5562, 5564, 5569, 5570, 5875; CM 33990, 33993 (~9 individ- uals).
ala
Fic. 1. a. Nemavermes mackeei Schram, 1973, UM 5554 with hair or seta (arrow), scale S mm; b. Archi- symplectes rhothon Schram, 1973, CM 33941, scale 5 mm; c, d. Soris labiosus gen. et sp. nov., UM 5548, with paired jaws and lips, scale | mm inc, | cm in d (arrow indicates jaws); e. Unnamed shape resembling a nematode, scale 5 mm; f. UM 5557, unnamed shape resembling a sipunculid, scale 5 mm; g. Carbosesostris megaliphagon gen. et sp. nov., UM 5542, closeup of jaw apparatus, scale | mm.
Remarks.—Several specimens have been identified which possess a nematode-like body, and preserve fine hairs or setae-like structures (UM 5554) on the cuticle (Fig. la). These are virtually identical to the Essex fauna species N. mackeei. With so little anatomy to analyze it seems best to assign these Bear Gulch fossils to the Illinois species.
dit
Fic. 2. a. Carbosesostris megaliphagon, gen. et sp. nov., UM 5542, scale 5 mm; b, c. Unnamed worms: b, CM 33939, probably polychaete, scale 5 mm, c, CM 33943, part of a segmented worm, scale 5 mm; d, e. Ramesses magnus gen. et sp. nov.: d, UM 5552, terminal end showing longer setae, scale 5 mm, e, UM 5553, midbody showing acicula along ventral surface, scale 5 mm.
Phylum Annelida
Class Polychaeta
Order Pyllodocida
Family Goniadidae Genus Carbosesostris gen. nov.
Diagnosis.—The diagnosis of the genus is the same as that of the species.
113
4
Fic. 3. Reconstruction of Bear Gulch worms. a. Jaw apparatus of Phiops aciculorum, with maxillae numbered; b. Phiops aciculorum; c. Astreptoscolex anasillosus; d. Soris labiosus, e. Ramesses magnus; f. Paired macrognaths of Carbosesostris megaliphagon; g. Carbosesostris megaliphagon; h. A micrognath element of Carbosesostris megaliphagon, arrow indicating inner edge of ring: 1. Deuteronectanebos papil- lorum.
Etymology.—Name derived from the age of the fossils and after a series of XIIth dynasty pharoahs from the Greek kings list of the Ptolemaic historian, Manetho.
Carbosesostris megaliphagon sp. nov. Fig. lg; Fig. 2a; Fig. 3f, g, h
Diagnosis. —One pair of complex macrognaths; 30-40 **H’’-shaped micrognaths in a ring; body long with apparently uniramous parapodia without acicula.
Holotype.—UM 5542 (Fig. 2a).
Type locality.—As described in the INTRODUCTION.
114
Fic. 4. a,b. Astreptoscolex anasillosus UM 5872, scale 5mm ina, scale 1 mminb; c,d. Phiops aciculorum gen. et sp. nov., UM 5543: c, CM 33945, closeup of jaw apparatus, scale | mm, d, head end with jaw apparatus and anterior acicula, scale 1 mm.
Etymology.—A reference to the magnificent jaw apparatus.
Material.—UM 5542, 5871, 6355 (3 individuals); CM 33988, 33989.
Description.—The macrognaths are 1-2 mm long and composed of 2 portions (Fig. 3f); a posterior region with 4 large denticles widely spaced in a fan-like arrangement, and an anterior region composed of a serrate blade (best preserved on UM 5542 [Fig. 1g] and UM 5871). The micrognaths number 30 to 40 and are arranged in an open ring posterior to the macrognaths. The micrognaths (Fig. 3h) are *‘H’’-shaped, with the uprights facing the outside of the ring very long making the individual elements almost ‘*U’’-shaped; the crossbar of the *‘H’’ has an inwardly directed spine. The body of the
11S
animal is between 6 to 9 cm long, clearly segmented, and adorned with apparently simple uniramous, short parapodia (UM 6355) with no setae or acicula visible. The segments occur at a rate of 8 every 10 cm.
Remarks.—Carbosesostris megaliphagon is the most abundant of the Bear Gulch polychaetes and is related to a known living group. A large macrognath and the mi- crognath ring place it in the family Goniadidae. Thompson (1979) described a goniadid, Pieckonia helenae, which possessed a distinctive set of ‘‘chair-shaped’’ micrognaths, with 2 pronged roots and 4 pronged teeth, and no macrognaths. The distinctive differ- ences in micrognaths between P. helenae and C. megaliphagon, and the presence of macrognaths in the latter, justify the erection of a separate genus and species for the Bear Gulch material. A reconstruction of Carbosesostris megaliphagon is offered in Fig. 3g.
Family Nephtyidae Genus Astreptoscolex Thompson, 1979 Type species Astreptoscolex anasillosus Thompson, 1979 Astreptoscolex anasillosus Thompson, 1979 Fig. 4a. b: Fig, 3¢
Material.—UM 5872, 5874, 5876.
Remarks.—The species is rare in the fauna and only 2 specimens have been de- finitively assigned to the species (UM 5872 and 5876) along with a questionable third (UM 5874). The body is large and fleshy (UM 5872 is just over 9 cm long and ~1 cm at its widest, with about 74 segments). The segments are all well demarcated and possess large biramous parapodia. Several of the parapodia bear acicula which appear to have been somewhat flexible because some of them are bowed or curved. The anterior end of the animal is blunt and the posterior end somewhat tapered. Both good specimens have some organic remains which mark the gut and UM 5872 has pellets in the gut. UM 5872 also has what appear to be molds of a small set of jaws (Fig. 4b).
Although Astreptoscolex is the best preserved of the Bear Gulch polychaetes, the assignment to the family Nephtyidae must retain some query. The general form of the body and the apparent presence of a simple jaw apparatus suggests this family, but lack of better preservation of the prostomium, palp, and tentacle structures makes the family assignment less secure than I would like. The only other family this body form might suggest would be the Nereidae, but the nereids have paragnaths and large jaws in the proboscis. A reconstruction of the Bear Gulch Astreptoscolex is offered in Fig. 3c and closely resembles that of Thompson (1979).
Order Eunicida Family Lumbrinereidae Genus Phiops gen. nov.
Diagnosis.—The diagnosis of the genus is the same as that of the species. Etymology.—Named after the VIth dynasty pharaoh, Pepi II, from the Greek kings list of the Ptolemaic historian, Manetho.
Phiops aciculorum sp. nov. Fig. 3a, b; Fig. 4c, d; Fig. 5a
Diagnosis.—Complex jaw apparatus with mandible and at least 4 pairs of maxillae on each side; mandible with pointed lateral wing; maxilla I (forceps) anteriorly devel- oped as 2 large denticles, maxillae II-IV multidentate through most of their lengths; large acicula on parapodia.
Holotype.—UM 5543 (Fig. 4d).
Type locality.—As described in the INTRODUCTION.
Etymology.—A reference to the prominent acicula.
Material.—UM 5543, 5873; CM 33944, 33945.
116
Fic. 5. a. Phiops aciculorum, CM 33945, closeup of jaw apparatus, scale 1 mm: b. Unnamed shape resembling a nematode, UM 5556, scale 1 mm, c, d. Deuteronectanebos papillorum, gen. et sp. nov., UM 5545: c, (r) longitudinal striations, (p) papillations, scale 5 mm, d, worm doubled back on itself off the edge of the slab, scale 5 mm.
Description.—The best specimen, UM 5543, has the jaw apparatus moderately well preserved on the left side, but somewhat less so on the right (Fig. 4d). CM 33944 and CM 33945 also preserve almost complete sets of jaws. The mandibles are fan- shaped, markedly pointed laterally (Fig. Sa), and appear to have been fused at the midline. There are at least 4 pairs of maxillae. Maxilla I (forceps) has 2 long denticles directed anteriorly from a serrated posterior region. Maxilla II has several large den- ticles in a fan-like arrangement with the denticles at either end of the series distinct from the center 5 (Fig. 4d). Maxilla HII is developed as a long sigmoid blade with serrations on the anterior end (Fig. 4c). Maxilla IV is square-shaped with a serrated cutting margin (Fig. 4c, d). The carriers, though not well preserved, are short and broad (Fig. 3a).
ele
The acicula are large and thick with longitudinal striations. There appear to have been 2 per parapodium. The parapodia themselves were lobate (UM 5873). The holo- type (UM 5543) has at least 27 segments preserved, but the animal is missing the posterior end.
Remarks.—The complex jaw apparatus clearly marks Phiops as a eunicidan. The short carriers and paired elements along the whole series indicate a lumbrinereid. Eunicids have asymmetrical maxillae; arabellids and lysaretids would have long slender carriers; and dorvilleids would have the maxillary elements developed as numerous pieces in a long series. The serration pattern on the jaw elements of Phiops is clearly unlike anything Kielan-Jawarowska (1966) describes in her monographic treatment of intact jaw apparatuses.
A partial reconstruction of Phiops aciculorum is given in Fig. 3b.
Order incerta sedis Genus Soris gen. nov.
Diagnosis.—The diagnosis of the genus is the same as that of the species. Etymology.—Named after the founder of the [Vth dynasty, Pharaoh Snofru, as taken from the Greek kings list of the Ptolemaic historian, Manetho.
Soris labiosus sp. nov. hres iced: Wig, 3d
Diagnosis.—Jaw a narrow falx; no denticles on the inner margin; some indication of faint serrations on the outer margin; prominent lips.
Holotype.—UM 5548 (Fig. Ic, d).
Type locality.—As described in the INTRODUCTION.
Material.—UM 5548, 5549.
Description.—The jaws on the holotype are ~1 mm long and what has been pre- served of the body is ~5 cm (posterior end missing). The jaws are simple scimitars, having a single narrow falx arising from a nondenticulated base. There is some slight indication that the outer margin of the jaws may have been serrate. Anterior to the jaws on UM 5548 is a dark ring (possibly the remnants of the lips of the proboscis). The ring does not display any structure under high power, thus suggesting it represents preservation of dense organic tissue rather than any ring of jaw elements.
The body itself is only incompletely preserved on the holotype and hardly at all on UM 5549. The posterior terminus is missing. No parapodia can be seen. Only faintly delineated somite boundaries can be discerned.
Remarks.—Sufficient soft anatomy has not been preserved in Soris to be able to refer it to an order. The jaws alone are not sufficient to do so. There is some slight resemblance of the jaws of S. labiosus to the scolecodont genera Glycerites Hinde, 1879, and Paraglycerites and Paranereites Eisenack, 1939. But the relatively straight posterior margin and the apparent lack of a prominent myocoel opening at the base serves to separate Soris from these other genera.
Conway Morris (personal communication) has noted a Soris-like jaw in the gut of one of the “‘conodont-eating’’ animals.
A partial reconstruction of Soris labiosus is offered in Fig. 3d.
Genus Ramesses gen. nov.
Diagnosis.—The diagnosis of the genus is the same as that of the species. Etymology.—Named after the series of XIXth and XXth dynasty pharaohs. Ramesses magnus sp. nov.
Bigs 2d. 6; Fig. 3k
Diagnosis.—Short body segments; short, stout parapodia with thick short acicula; terminus of body with parapodia armed with thick long setae.
118
Holotype.—UM 5552 (Fig. 2d).
Type locality.—As described in the INTRODUCTION.
Etymology.—After the great XIXth dynasty pharaoh, Ramesses I.
Material.—UM 5550-5553, 5560, 5877.
Description. —The body is very long and narrow. But the length is indeterminate since only one specimen (UM 5877) is anything approaching a complete animal, the two termini poorly preserved on one counterpart and only one preserved at all on the other. The body is composed of short somites (UM 5552) with the aciculate parapodia located along one surface (UM 5553; Fig. 2e). The aciculae are single, stout, and short. At one terminus (possibly the posterior), the last 8 to 10 segments have parapodia with long setae.
Remarks.—All the specimens at hand are best studied under water to bring out the details of preservation.
In some respects, the body form of Ramesses, with its short segments and short, stout parapods along one surface is similar in some respects to the modern polychaete family Orbiniidae. But without better information about the terminal ends, a definitive placement of Ramesses within a family cannot be undertaken.
A partial reconstruction of Ramesses magnus is offered in Fig. 3e.
Phylum uncertain Genus Deuteronectanebos gen. nov.
Diagnosis.—The diagnosis of the genus is the same as that of the species. Etymology. —Named after the XX Xth dynasty and last native pharaoh, Nectanebo II, from the Greek kings list of the Ptolemaic historian, Manetho.
Deuteronectanebos papillorum sp. nov. Fig. 5c, d: Fig. 31
Diagnosis.—Body long and narrow; cuticle marked with faint longitudinal stria- tions and prominent papillations.
Holotype.—UM 5545 (Fig. 5d).
Type locality.—As described in the INTRODUCTION.
Etymology.—A reference to the prominent papillae.
Material.—UM 5544-5546, 5561, 5819.
Description.—The specimens at hand range from 4 to 25 cm in length. The body is marked along its length by prominent papillations (Fig. 5c). In addition, longitudinal striations are noted and are best preserved on UM 5545. The body is narrow and tapered at what appears to be its posterior end. No jaws, cirri, or palps are noted on any of the specimens.
Remarks.—Though the diagnostic papillated and striated surface of Deuteronec- tanebos is very striking, the assignment to phylum must be uncertain. The order Cap- itellida in the annelids is suggested by the resemblance of Deuteronectanebos to certain living forms as illustrated by Hartman (1947). But the similarity is inconclusive.
The possibility of this rather nondescript species not being animal has been con- sidered. A possible algal affinity is suggested, but Dr. Matthew Nitecki, Field Museum, examined the specimens and concluded (personal communication) they were not algal.
Genera and species uncertain
Several specimens were found in the Bear Gulch material which should not be named because of their poor preservation and paucity of material. Some of the more intriguing specimens are illustrated here. One can only speculate as to what they might be: e.g., UM 5557 (Fig. If) suggests the form of a sipunculid; CM 33939 (Fig. 2b) iS obviously some type of polychaete; and CM 33943 (Fig. le) may be some type of segmented worm. UM 5555 (Plate 1, Fig. 5) and UM 5556 (Fig. 5b) resemble nematodes and may be synonymous with Nemavermes. In addition, there are numerous speci-
119
mens which can only be characterized as ‘‘vermoid.’’ The material itself is such poor quality, however, that one cannot really be sure whether some of these are real organic remains or just some preservational or sedimentary artifacts.
ACKNOWLEDGMENTS
Thanks must be extended to W. Melton, University of Montana; Richard Lund, Adelphi University; and John Carter, Carnegie Museum, for the loan of material to study. Photographic work was done by Dan Stephenson.
LITERATURE CITED
Baird, G. 1979. Lithology and fossil distribution, Francis Creek Shale, northeastern Illinois. Jn M. H. Nitecki, editor. Mazon Creek Fossils. Academic Press, New York. 41-68.
Conway Morris, S. 1977a. A redescription of the Middle Cambrian worm Amiskwia sagittifor- mis from the Burgess Shale of British Colum- bia. Palaeontologische Zeitschrift 51:271—287.
Conway Morris, S. 1977b. Fossil priapulid worms. Special Papers in Palaeontology 20: 1— 95.
Day, J. H., Field, J. G., and Montgomery, M. P. 1971. The use of numerical methods to deter- mine the distribution of the benthic fauna across the continental shelf of North Carolina. Journal of Animal Ecology 40:93-125.
Dollfus, R. P. 1950. Liste des Nemahelminthes connus a l’etat fossile. Compte Rondu Som- maire et Bulletin Societe Geologique de France. 20 (series 5):82-85.
Ehlers, E. 1868. Ueber eine fossile Eunicee aus Solenhofen (Eunicites avitus) nebst Bemer- kungen ueber fossile Wuermer ueberhaupt. Zeitshrift wissenschaftliche Zoologie 18:421- 443.
Eisenack, A. 1939. Einige neue Annelidenrests aus dem Silur und dem Jura des Baltikums. Zeitschrift Geschiebeforschung Flachlan- dsgeologie 15:153-176.
Hartman, O. 1947. Polychaetous annelids, Part 7, Capitellidae. Allan Hancock Pacific Expedi- tion 10(4):391—481.
Hinde, G. J. 1879. On annelid jaws from the Cam- bro-Silurian, Silurian, and Devonian forma- tions in Canada and from the Lower Carbon- iferous of Scotland. Quarterly Journal Geological Society, London 35:370-389.
Jones, D., and Thompson, I. 1976. Echiura from the Pennsylvanian Essex fauna of northern II- linois. Lethaia 10:317—325.
Kielan-Jawarowska, Z. 1966. Polychaete jaw ap- paratuses from the Ordovician and Silurian of Poland and a comparison with modern forms. Paleontologica Polonica 16:1—152.
Lund, R. 1974. Stethacanthus altonensis from the Bear Gulch Limestone of Montana. Annals, Carnegie Museum 45:161-178.
Lund, R. 1977a. A new petalodont from the Up- per Mississippian of Montana. Annals, Car- negie Museum 46:129-155.
Lund, R. 1977b. Echinochimaera meltoni, a new genus and species from the Mississippian of
Montana. Annals, Carnegie Museum 46:195— 221.
Lund, R., and Zangerl, R. 1974. Squatinactis cau- dispinatus, a new elasmobranch from the Up- per Mississippian of Montana. Annals, Car- negie Museum 45:43-SS.
Melton, W. G. 1969. A new dorypterid fish from central Montana. Northwest Science 43:196— 206.
Melton, W. G. 1971. The Bear Gulch fauna from central Montana. Proceedings, North Ameri- can Paleontological Convention, Chicago, 1969. Part I: 1202-1207.
Melton, W. G., and Scott, H. W. 1972. Conodont bearing animal from the Bear Gulch Lime- stone, Montana. Geological Society of Amer- ica Special Paper 141:31-65.
Nitecki, M. H., and Schram, F. R. 1976. Etacystis communis, a fossil of uncertain affinities from the Mazon Creek fauna. Journal of Paleontol- ogy 50:1157-1161.
Oglesby, L. G. 1969. Salinity stress and desicca- tion in intertidal worms. American Zoologist 9:319-331.
Parker, R. H. 1956. Macro-invertebrate assem- blages as indicators of sedimentary environ- ments in the east Mississippi delta region. Bul- letin, American Association of Petroleum Geologists 40:295-376.
Schram, F. R. 1973. Pseudocoelomates and a nemertine from the Illinois Pennsylvanian. Journal of Paleontology 47:985—989.
Schram, F. R. 1979. The Mazon Creek biotas in the context of a Carboniferous faunal contin- uum. Jn M. H. Nitecki, editor. Mazon Creek Fossils. Academic Press, New York. 159-190.
Schram, F. R., and Horner, J. 1978. Crustacea of the Mississippian Bear Gulch Limestone of central Montana. Journal of Paleontology 52:394—406.
Scott, H. W. 1973. New Conodontochordata from the Bear Gulch Limestone (Namurian, Mon- tana). Publications of the Museum, Michigan State University Paleontology Series 1:85—99.
Seilacher, A. 1970. Begriff und Bedeutung der Fossil-Lagerstatten. Neues Jahrbuch Geologie Palaeontologie Monatshefte 1970:34—-39.
Shabica, C. W. 1979. Pennsylvanian sedimenta- tion in northern Illinois: evidence for a deltaic- eustatic model. Jn M. H. Nitecki, editor. Ma- zon Creek Fossils. Academic Press, New York. 13-40.
Smith, R. I. 1955. On the distribution of Nereis diversicolor in relative salinity in the vicinity of Tvarminne, Finland, and the Isefjord, Den- mark. Biological Bulletin 108:326—345.
120
Stormer, L. 1963. Gigantoscorpio willsi, a new scorpion from the Lower Carboniferous of Scotland and its associated preying microor- ganisms. Skrifter utgitt ay Det Norska Viden- skaps-Akademi i Oslo I, Math-Nuturv. Klasse Ny Serie. no. 8:1-171.
Taylor, A. L. 1935. A review of the fossil nema- todes. Proceedings of the Helminthological Society, Washington 2:47-49.
Thompson, I. 1979. Errant polychaetes from the Pennsylvanian Essex fauna of northern Illi- nois. Palaeontographica. Abt. A. 163:169-199.
Thompson, I., and Johnson, R. G. 1977. New fos- sil polychaete from the Essex fauna of Illinois. Fieldiana: Geology 33:471-—487.
Walcott, C. 1911. Middle Cambrian annelids. Smithsonian Miscellaneous Collections 57:109- 142.
Whittington, H. B. 1975. The enigmatic Opabinia regalis, Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions, Royal Society, London 271:1-43.
Department of Paleontology, San Diego Natural History Museum, San Diego, Cali-
fornia 92112, USA.
TRANSACTIONS
: OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 10 pp. 121-151 12 December 1979
A revision of the subfamily Syneurycopinae (Isopoda: Asellota: Eurycopidae) with a new genus and species (Bellibos buzwilsoni)
Julie Ann Haugsness and Robert R. Hessler
Abstract. Yo date, the subfamily Syneurycopinae has accommodated a single genus, Syneury- cope, and 8 morphologically diverse species. The present taxonomic revision of the subfamily syn- onymizes 3 of these species, creates a new genus with 2 subgenera, Bellibos (Bellibos) and B. (Be- merria), and describes one new species, Bellibos (Bellibos) buzwilsoni. A key to the subfamily is provided. Size-frequency and meristic variability data are provided for a particularly well-sampled species, B. buzwilsoni. Biogeographic information is presented, based on material collected from all regions of the Atlantic Ocean. Those species that are known from more than one locality have wide- spread distributions.
INTRODUCTION
The Eurycopidae is one of the largest and most abundant families of deep-sea isopods. As with the other large families, its systematics badly needs revision. The diagnostic features of most of its higher taxa are unclear, likely synonymies go unat- tended, and a few genera tend to be made the repository for most new species, even though these species represent a range of morphologies well in excess of what a mean- ingful genus should contain. The present-paper is the first of a series whose purpose is to revise the family in a useful way. We begin here with the Syneurycopinae, one of the smaller and more circumscribed of the 4 eurycopid subfamilies.
The genus Syneurycope was established by Hansen (1916) as one of a cluster of genera in his Group Eurycopini; Syneurycope contained a single species, Syneurycope parallela. Barnard (1920) erected a new genus and species, //ycthonos capensis, and included it in an entirely different taxon, the Desmosomatidae (Wolff, 1962), although at the time Barnard recognized that the genus was ‘“*. . . perhaps congeneric with Syneurycope Hansen, 1916.’ Menzies (1956) synonymized Ilychthonos with Syneu- rycope, retaining the species as Syneurycope capensis. He established the family Eu- rycopidae, including Syneurycope as one of 4 genera, and described a new species, Syneurycope hanseni. Later, Menzies (1962) described 2 more species, Syneurycope heezeni and Syneurycope multispina. In his general revision of the Paraselloidea, Wolff (1962) divided the Eurycopidae into 4 subfamilies, including the monogeneric Syneu- rycopinae. In 1970, Birstein described Syneurycope affinis. Most recently, Chardy (1975) added 2 species: Syneurycope dageti and Syneurycope monicae.
Taken together, this collection of species encompasses a broad range of mor- phologies. The trunk may be dorsoventrally flattened or strongly vaulted. The cephalon may or may not bear large horns or other distinctive sculpturing. The first pereonite may be fused to the cephalon, or it may be free; it can be equal in size to the other anterior pereonites or much larger. The natasome (Hessler and Thistle, 1975) varies markedly in size relative to the ambulosome. The pleotelson is complexly contoured in some species, simple in others. Accepting the criterion that members of a genus
122
should look much alike, this suite of species, although related, clearly should be con- sidered representatives of more than one genus. In this paper we have defined two genera: a restricted Syneurycope Hansen, 1916, and a new genus, Bellibos. The extent of morphological similarity of congeners in each of the two resulting genera is some- what different. The existence of more than one species in Syneurycope is well founded, with differences of the same order seen in genera of other deep-sea isopod families. However, Bellibos species encompass a wider range of morphologies than usual; we have therefore split them into 2 natural groupings which we diagnose as the new subgenera, Bellibos and Bemerria.
We have examined the available types of every published species except for the single Pacific species, Syneurycope affinis Birstein, 1970. It became obvious that the independence of S. capensis and S. hanseni from S. parallela could not be supported, and they are synonymized herein. The types of B. dageti and B. monicae have ap- parently been lost in the mail between Brest and Paris, France, en route to the National Museum of Natural History (M. M. Forest and P. Chardy, personal communication). We describe specimens from our collection that we have tentatively assigned to these 2 species; although our specimens differ from Chardy’s descriptions of B. monicae and B. dageti in a few potentially diagnostic characters, there remains insufficient evidence to describe them as new species. The type-material of B. multispina stands as the only collected specimens of this unique species. A new species (Bellibos buz- wilsoni) is described here which is quite unlike anything seen before. As redefined in this paper then, the Syneurycopinae contains 2 genera, 2 subgenera, and 7 species.
In spite of the morphological breadth of the Syneurycopinae, the subfamily is a strong natural unit. Its diagnosis contains a number of unusual and seemingly unrelated features: the fusion of pereonites 5-7, the absence of maxillipedal coupling hooks, the presence of medial denticles on the third article of the maxillipedal palp, the short branchial chamber, and the apical cleft of the female operculum.
The syneurycopine species most similar to other eurycopids is B. buzwilsoni. Compared to other members of the subfamily, it has the broadest, deepest body; the first pereonite is unspecialized and articulates freely with the cephalon; its natasome is the largest, relative to body size; its swimming pereopods (pereopods V—VII) have broad carpi and propodi; the pleotelson shape is simple; and the uropodal rami are both well developed. In general body shape, B. buzwilsoni is reminiscent of Betamor- pha Hessler and Thistle (1975).
Syneurycope parallela is certainly the most specialized species, as seen in its slender body, the complete fusion of pereonite | and the cephalon, its short natasome, slender pereopods V-VII, complexly contoured pleotelson, and reduced uropodal ex- opod. Bellibos buzwilsoni and Syneurycope parallela bracket most of the morpholog- ical variation in the Syneurycopinae. The unique inflated cephalon of B. multispina and expanded pereonite | of B. monicae are the major exceptions to this.
Basically, the syneurycopine species are pan-Atlantic. The distributional map (Fig. 1) shows some gaps in this pattern which may be a result of unequal sampling effort. Only Bellibos multispina is restricted to a single station. Syneurycope heezeni and Bellibos dageti are restricted to the South and North Atlantic, respectively. The other species exhibit impressive horizontal distributional ranges. Although this is not atypical for a family or even a genus, it is unusual for most species of a subfamily to be known to range so widely. The existence of Syneurycope affinis extends the distribution of the Syneurycopinae to the Pacific Ocean as well.
The depth distribution is basically abyssal with most species occurring over a range of ~2000 metres. The major exceptions to this scheme are B. multispina and S. affinis, known from but a single station, and S. parallela, which is very wide-ranging (from 1280 to 5122 metres, a range of nearly 4000 metres).
Materials. —The Woods Hole Oceanographic Institution deep-sea sampling pro- gram is the source for most of the material used in this study. This program has sampled, with an epibenthic sled, a series of transects originating on the continental shelf and running out to the abyssal plain. These transects are located off the north-
123
° co} S Se 8 a 110° Se — 390° ES ° > > ‘ OQ. oD js 30°) 10° Ys CS) j ies aaa ° 2 2 > S
02
° <0e
J0o
80° 008
FiGuRE |. Geographical distribution of syneurycopine species in the Atlantic Ocean. Species are symbol- ized by numbers: 1, Syneurycope parallela; 2, Syneurycope heezeni; 3, Bellibos buzwilsoni; 4, Bellibos dageti; 5, Bellibos multispina; 6, Bellibos monicae. Each number locates a single station except where circled; circled numbers indicate approximate location of a cluster of 2 or more closely spaced stations (see Table 1 for complete listing of station data).
eastern United States (Gay Head—Bermuda transect), Surinam, northern Brazil, Ar- gentina, Namibia, Angola, Senegal, and Ireland. Additional isopod material comes from the Bay of Biscay (J. Allen, University of Newcastle-upon-Tyne), the Canary Islands (J. Allen), and the Weddell Sea (J. Rankin, University of Connecticut). Station data are given in Table 1.
Newly assigned type-specimens are deposited in the United States National Mu- seum (USNM), Washington, D.C. Paratypes and/or additional material are also de- posited in the Zoological Museum, University of Copenhagen (ZMUC), Copenhagen, Denmark. The remaining material resides in the second author’s working collection at Scripps Institution of Oceanography (SIO), La Jolla, California, but will ultimately be deposited in the USNM.
Methods.—The methods used to collect and treat the samples, and to preserve the animals have been previously described (Sanders et al., 1965; Hessler and Sanders, 1967; Hessler, 1970).
124
TABLE |. Station data for the Syneurycopinae of the present study. Species found at each station are listed by number: /, Syneurycope parallela; 2, Syneurycope heezeni; 3, Bellibos buzwilsoni; 4, Bellibos dageti; 5, Bellibos multispina; 6, Bellibos monicae. Source abbreviations: Woods Hole Oceanographic Institution (WHOI); Lamont Geological Observatory (LGO); John A. Allen (JA); J. S. Rankin/United States Coast Guard Cutter Glacier (R); Pieter Faure (PF); Danish Ingolf Expedition (IE); Biogas IV/RV Jean Charcot (BIV); Biacores/RV Jean Charcot (B).
Source Station Latitude Longitude Depth (m) Species WHOI 62 39°26.0'N 70°33.0'W 2496 1 63 38°46.8'N 70°05.7'W 2891 1 64 38°46.0'N 70°06.0' W 2886 res 66 38°46.7'N 70°08.8’ W 2802 Ihe WW 38°08.0'N 71°47.5'W 2946 4 72 38°16.0'N 71°47.0'W 2864 il, C 76 39°38.3'N 67°57.8'W 2862 1 100 33°56.8'N 65°47.0'W 4743-4892 4 103 39°43.6'N 70°37.4'W 2022 1 126 39°37.0'N 66°47.0'W 3806 1,4 131 36°28.9'N 67°58.2'W 2178 1 155 00°03.0'S 27°48.0'W 3730-3783 3,4 156 00°46.0'S 29°28.0'W 3459 Il ohy 2 © 195 14°40.0'S 09°54.0’E 3797 3,6 200 09°41.0'S to 10°55.0’E to 2644-2754 1 09°43.5’S 10°57.0'E 242 38°16.9'S 51°56.1'W 4382-4402 ] 245A 36°55.7'S 53°01.4’W 2707 il, 3} 256 37°40.9'S 52°19.3'W 3906-3917 1 287 13°16.0'N 54°52.2'W 4934-4980 3 288 11°02.2'N 55°05.5'W 4417-4429 4 303 08°28.8'N 56°04.5’W 2842-2853 I 313 51°32.2’N 12°35.9'W 1491-1500 I 321 50°12.3'N 13°35.8'W 2868-2890 hy SS 323 50°08.3'N 13°50.9’W to 3338-3356 1 13°53.7°W 326 50°04.9'N to 14°23.8’W to 3859 | 50°05.3'N 14°24.8'W 328 50°04.7'N 15°44.8'W 4426-4435 1,3,4 330 50°43.4'N 17°52.0’W 4632 3,4 LGO I 20°32.2’N 60°28. 1'W 4941-4959 1 52 41°03.0'S 07°49.0’E 4960 5 200 55°42.9'S 64°21.6’W 3813 2 201 55°31.2'S 64°07.5'W 3839 2 220 09°45.0'S 34°24.0'W 3222-3336 2 JA 50 43°46.7'N 03°38.0'W 2379 ly Sin 6711 27°14.9'N 15°36.3'W 2988 | R 1969/21 ES 73°52.0'S 31°18.0'W 2288 2, 1969/23 ES 72°47.6'S 30°29.7'W 3697 6 PF ‘*Cape Point North 89° East, distant 36 miles [~58 km]”’ 1281 1 IE 22 58°10.0'N 48°25.0'W 3376 | BIV 2 47°31.0'N 09°09.7'W 2835 4 B 245 40°57.0'N 22°16.0'W 4270 6
The illustrations were made using a compound microscope equipped with a camera
lucida. Measurements were obtained from the drawings. Total body length was mea- sured dorsally from the anterior edge of the cephalon to the posterior tip of the pleo- telson, along the midsagittal line. Cephalon and pereonite length were also measured midsagittally; pereonite width was measured transversely at the greatest tergal span. The length of various antennal articles and podomeres was measured along the longest axis; the width was measured perpendicular to the length at the widest span. Uropodal ramal length included that part of the ramus which is embedded in the protopod.
125
Length:width ratios (hereafter abbreviated I/w) were obtained from these measure- ments. The reader should be cautioned that the morphological measurements and me- ristic counts cited in this paper were obtained from a single specimen unless a range of variation is given.
The various types of setae are defined and illustrated in Hessler (1970). **Nata- some’’ refers to pereonites 5-7, pleonite 1 and the pleotelson along with the corre- sponding appendages (Hessler and Thistle, 1975). The female second pleopod is termed the operculum and frequently possesses a ventral, midsagittal ridge referred to as the ‘‘keel.’’ The pleotelson is described as ‘‘complexly contoured”’ when it no longer has a simple undifferentiated shape with gently tapering sides, but exhibits well-defined surface topography with abrupt discontinuities in pleotelson width.
Descriptions and illustrations are based on previously undescribed material from the second author’s working collection unless otherwise noted. The identity of these specimens was confirmed by direct comparison with the corresponding holotype. Spe- cific mention is made wherever our material is known to differ from the type-material. The following type-material was examined for this study: (1) American Museum of Natural History, New York: Syneurycope hanseni Menzies, 1956, holotype; Syneu- rycope heezeni Menzies, 1962, holotype, paratype and additional material; Syneury- cope multispina Menzies, 1962, holotype, allotype and paratype. (2) South African Museum, Cape Town: Syneurycope capensis (Barnard, 1920), syntypes. (3) Zoological Museum, University of Copenhagen, Denmark: Syneurycope parallela Hansen, 1916, holotype.
SYSTEMATICS Syneurycopinae Wolff, 1962
Diagnosis.—Eurycopidae with elongate body, I/w >3.0. Pereonites 5-7 fused. Antenna I positioned terminally on cephalon, first article subcylindrical. Maxillipeds lack coupling hooks, may be fused in part; third article of palp with medial denticles; epipod large. Branchial chamber and operculum short with respect to length of pleo- telson; 2 pleopod II (operculum) apically cleft. Uropods biramous, flattened.
Syneurycope Hansen, 1916 Figures 2-6
Synonymy.—Syneurycope Hansen, 1916, pp. 130-131; Menzies, 1956, pp. 5-6; Menzies, 1962, pp. 150-151; Wolff, 1962, pp. 108-109, 116-117. Ilychthonos Barnard, 1920, pp. 414-415.
Type-species.—Syneurycope parallela Hansen, 1916, pp. 131-132, Pl. XII, Figs. 4a—4o.
Distribution. —Eastern and western Atlantic Ocean, 58°10'N to 73°5S2’S, 1280-5122 m. Northwestern Pacific Ocean, 44°48’N, 5005-5045 m.
Diagnosis.—Syneurycopinae with body I/w always >4.0. Combined length per- eonites 1-4 always > pereonites 5—7. Cephalic spines absent; medial dorsal surface cephalon raised; cephalon fused to first pereonite. Pleotelson complexly contoured. Antenna I, ° flagellum a single article. Pereopod V carpus slender where known; I/w >2.5. Female operculum widest in proximal half, tapering distally; median keel poorly developed. Pleopod I, adult ¢ with outer ramus of distal end unusually elongate, equal in length to that of inner ramus, where known. Pleopod II, adult 5 with distal tip of protopod elongate, extending distally far beyond exopod, where known. Uropod with strongly reduced exopod bearing | or 2 large, apical setae; length exopod % or less length endopod.
Additional description.—The characteristically elongate pereopods III and IV of Syneurycope parallela are now known for S. heezeni also. The merus, carpus, pro- podus, and dactylus are all greatly elongated, with carpus I/w > 10 and propodus 1I/w
126
FiGuRE 2. Syneurycope parallela preparatory 2, WHOI 131: A. body, lateral view, setae omitted; B. body, dorsal view; D. cephalon-pereonite 1, ventral view; F. plumose seta, enlarged view, typical of setae on operculum and posterior medial margins of pleotelson; G. pleotelson, ventral view, setae omitted from uropod and edge of operculum; H. left uropod, ventral view, in situ. Male, WHOI 131: C. body, dorsal view; E. cephalon-pereonite 1, lateral view, pereopod I missing.
er
>20. This character is not diagnostic of Syneurycope because it remains unknown for most other syneurycopine species; it is likely to be diagnostic of the subfamily.
Remarks.—Syneurycope species are readily identifiable by the elongate body, the fusion of cephalon and first pereonite, the absence of cephalic horns, and the short uropodal exopod. One other syneurycopine species, Bellibos monicae, shares the gen- eral body proportions of Syneurycope; however, other features clearly differentiate it from this genus.
Hansen’s original generic description is accurate only for the single species on which it was based, Syneurycope parallela. None of the later treatments of the genus are concise; they include specific and familial characters.
The genus has previously been made recipient of 8 species: Syneurycope parallela Hansen, S. capensis (Barnard), S. hanseni Menzies, S. heezeni Menzies, S. affinis Birstein, S. multipsina Menzies, S. dageti Chardy, and S. monicae Chardy. The pres- ent revision synonymizes the first 3 species with S. parallela and removes the last 3 species to a new genus. This leaves Syneurycope with 3 species: S. parallela, S. heezeni and S. affinis.
Syneurycope parallela Hansen, 1916 Figures 2-3
Synonymy.—Syneurycope parallela Hansen, 1916, pp. 131-132, Pl. XII, Figs. 4a— 4o: Menzies, 1962, pp. 150-151, Fig. 41F; Wolff, 1962, pp. 116-117. Ilychthonos ca- pensis Barnard, 1920, pp. 415-416, Pl. XVII, Figs. 14-16. Syneurycope capensis Men- zies, 1956, pp. 5-6. Syneurycope hanseni Menzies, 1956, p. 6, Fig. 2.
Holotype.—Ingolf Station 22 (58°10'N, 48°25'W); ZMUC, ¢, 3.7 mm. Specimen in excellent condition; left maxilliped and left mandible dissected off, former lost and latter mounted on slide.
Other material.—Syneurycope capensis syntypes: ‘‘Cape Point North 89°E, dis- tant 36 miles’’ (Barnard, 1920), SAM A4030. Subadult 2° without uropods. Preparatory 2 with single uropod, no pleopods. Badly damaged ¢, pleopods I present, no uropods. Fragment: cephalon and anterior 7 pereonites, pereopod I present. Fragment: pleotel- son with uropod. Fragment: middle 6 pereonites, pereopod II present but detached. Syneurycope hanseni holotype: tropical Atlantic (20°32.2’N, 60°28.1'W), AMNH 11758, ¢, 3.8 mm. Specimen in very poor condition, flattened and badly decalcified. Absent limbs include: antennae II, maxilliped, and pereopods II, HI, and IV. No additional material. Present collection: WHOI stations 62 (1 individual); 63 (2); 64 (17); 72 (1); 76 (5); 103 (5); 126 (1); 131 (60); 156 (5); 200 (1); 242 (6); 245A 20% fraction (26); 256 (7): 313 (8); 321 (83); 232 (7); 326 (4); 328 (2). John Allen stations 48 (1); 50 (199); 6711 (1). Illustrated preparatory ° and copulatory ¢ (WHOI 131) deposited at ZMUC. Copulatory ¢ (WHOI 103), copulatory ¢ (WHOI 62), preparatory ° (WHOI 66) and brooding 2 (WHOI 131) USNM catalog nos. 173001, 173003, 173002, 173000, respec- tively.
Distribution. —Eastern and western Atlantic Ocean, 58°10'N to 38°17’S, 1280 to 5122 sms
Diagnosis. —Syneurycope with narrow body; body length preparatory female 4.4— 4.6x tergal width of pereonite 2; not fringed laterally with numerous simple setae. Pleotelson with pair of strongly flaring, proximal ventral flanges, paired dorsolateral bulbous midsections, and narrow drawn-out distal end. Antenna I, 2, first article approximately same width as second article, I/w >1.7; first 2 articles not fused although articulation is reduced; second article inserts centrally into first as their widths are approximately equal at this junction. Mandibular incisor process with 3—4 more or less distinct teeth; molar process truncate with marginal row of setae. Maxillipedal epipod pointed distally. Pereopod V carpus I/w 2.8; dactylus slender. Female operculum, apical cleft <'/s length of operculum. Uropodal endopod with 2 large apical setae and 2 stout lateral setae; exopod bears 2 apical setae.
128
FiGurE 3. Syneurycope parallela 36, WHOI 103: A. left antenna II, in situ, flagellum absent. Preparatory 2, WHOI 131: B. incisor process, mandible, plan view; C. lacinia mobilis, mandible, plan view; D. left mandible, third article of palp absent; E. left mandibular palp; G. left maxilliped,; L. operculum, setae are all plumose. Copulatory ¢, WHOI 62: F. left mandibular palp; H. left pereopod I, in situ; I. left pereopod V, in situ, setae are plumose; J. pleopods I; K. left pleopod II.
Additional description.—Preparatory @ larger than copulatory d: body length 25.5 mm, width 1.2 mm; body length ¢ 3.1 mm, width 0.6 mm; body length copulatory 3 4.9x tergal width of pereonite 2. Body widest at pereonite 2: I/w 0.6 preparatory 2, 0.5 copulatory ¢. Antenna I, ¢ flagellum multiarticulated; bases of antennae I nearly touching in ¢, separated by a shallow depression in 2. Mandibular palp, °,
129
apical article reduced with single apical seta; apical article, ¢d, palp robust with ap- proximately 4 setae.
Remarks.—Syneurycope parallela is easily distinguished from S. heezeni by the narrower body, the antenna I peduncle, and the exaggerated topography of the pleo- telson. It can be differentiated from S$. affinis by the condition of the molar process of the mandible. The setation of the uropodal endopod is also distinct.
The single discrepancy between our material and Hansen’s holotype is the number of setae on the natatory pereopods. Individual or geographic variation, ontogenetic development, and/or damage can easily account for this.
There are some problems with Hansen’s description and illustrations. The ceph- alon is illustrated by Hansen as articulating with the first pereonite. Careful examina- tion of the holotype and Scripps Institution of Oceanography specimens definitely indicates fusion of these 2 structures; no suture line is visible (Fig. 2B). This is a diagnostic feature of the genus in the present revision. Hansen illustrates coupling hooks on the maxilliped; coupling hooks are absent from all specimens examined throughout the entire subfamily (Fig. 3G). The holotype retains only the right maxil- liped, the left having been dissected off and subsequently lost. Examination of the single remaining maxilliped on the holotype reveals no coupling hooks. Hansen cor- rectly describes the male as ‘‘more than five times as long as the breadth of the fourth thoracic segment.’’ Our male body I/w of 4.9 is obtained by measuring the width of the second pereonite, as this is usually the broadest pereonite throughout the subfam- ily; measuring width at the fourth pereonite gives a I/w of 5.8. Hansen noted that the operculum “‘is very far from reaching the end of the abdomen’’ (Fig. 2G); this becomes a diagnostic feature of the subfamily in the present revision. The antenna I female peduncle consists of 3 articles of the same rough proportions as described by Hansen for the male (Figs. 2D, 2E). The 16 articles of the antenna I flagellum he describes are typical of the male only; the female flagellum is a single segment (Fig. 2D).
Sexually dimorphic characters are not presently included in the species diagnosis because no male S. heezeni or S. affinis has been collected.
The antenna II fifth article is extremely elongate (Fig. 3A). This article is rarely present on collected specimens.
In this revision, Syneurycope parallela Hansen, S. capensis (Barnard), and S. hanseni Menzies are synonymized. The type-specimens of all 3 species were carefully examined; all proved indistinguishable from S. parallela. They were simply poorly illustrated and wrongly described. When circumstances dictated, we reillustrated the type-material. All problems and errors in the literature are treated below.
Syneurycope capensis Figure 4: Barnard’s syntypes reillustrated
Barnard’s description contains many inaccuracies. Confusion results from his ne- glect to specify which of the 6 syntypes he has described. Barnard illustrated the first pereonite as discrete, yet careful inspection of the types shows it is fused with the cephalon (Fig. 4A). Pereonites 5, 6, and 7 are also illustrated as separate segments, but they are actually fused (Fig. 4A), as is typical of all species of Syneurycopinae. Barnard described a ‘“‘pleon of a single segment’’; the types actually have a reduced first pleonal segment, apart from the pleotelson (Figs. 4A, 4F). The antenna I flagellum is described as bearing ‘‘ca. twelve indistinctly separated joints”’ (Fig. 4B); this is true in the male alone, the female bears a flagellum of a single article (Fig. 4A). Furthermore, it indicates the immature condition of the male syntype, because adults typically bear closer to 16 articles. Additional evidence for an immature male syntype includes the truncate condition of the indistinctly bilobed distal end of the first pleopod (Fig. 4G), a second pleopod with a very stout stylet, and the feminine condition of the mandibular palp (Fig. 4D). The uropod is biramous, although described by Barnard as uniramous. The small exopod, ~'/; the length of the endopod, is easily overlooked (Fig. 4E). The remaining discrepancies between S. parallela and S. capensis involve the man-
130
Ficure 4. Syneurycope parallela (reillustration of Barnard’s Syneurycope capensis syntypes, S.A.M. A4030) preparatory 2: A. body, dorsal view, left distal edge of pleotelson damaged; C. left mandibular palp, in situ; E. left uropod, ventral view, in situ, setae are plumose. Nonpreparatory 2: F. pleotelson, ventral view, setae are plumose, setae omitted from medial margins of pleotelson and left edge operculum, uropods missing. Immature 6: B. left antenna I, in situ, second article damaged; D. left mandibular palp, in situ; Ge pleopods I, in situ.
dible and maxilliped, which are unavailable. Barnard describes the mandible with a ‘secondary cutting edge [as] bifid.” Presumably he is referring to the lacinia mobilis, which does appear bifid in lateral view, but is clearly quadradentate in plan view Tape parallela (Fig. 3C). Barnard describes the maxilliped as bearing an “‘inner distal margin of fifth [=third article of palp] with three denticles.”’ In S. parallela, this margin is armed with numerous irregular spiniform teeth (Fig. 3G); these small teeth are grouped into units, which Barnard refers to as denticles. The number of denticles present varies both ontogenetically and between individuals. They are prominent and discrete distally, progressively diminishing in size and becoming less distinct proximally. The number of denticles varies too much to be useful as a diagnostic or descriptive character. The presence of numerous denticles along this margin is typical of all syneurycopine
131
species. Data on the variability of this character are included in the treatment of Bel- libos buzwilsoni, sp. nov.
Syneurycope hanseni
In 1956, Menzies described S$. hanseni. Reexamination of the holotype demon- strated that it is a poorly preserved specimen of S. parallela. We have not reillustrated the holotype; Menzies’ drawings (Menzies, 1956b, Fig. 2) can be directly compared with our S. parallela illustrations, with the corrections indicated below.
The holotype is originally illustrated as having a discrete cephalon and pereonite 1; our examination reveals that they are fused. The basal pleonite is distinct; the partial sutures in Menzies’ drawings are incorrect. The original diagnosis contains other minor discrepancies. It includes the presence of ‘‘a well-developed mandibular palp’’ as a diagnostic character, but in the female it is reduced. The presence of ‘‘sixteen denticles along inner margin of second article’’ of the maxillipedal palp is also cited as diagnostic. Presumably, Menzies is referring to the third and not the second article, the variability of which has already been discussed. Menzies’ terminology differs from Barnard’s: a denticle now refers to a single projection or tooth. Reexamination of the holotype yields a different count from that of Menzies. Menzies’ illustration depicts each male pleopod I inner ramus with 3 apical setae; close inspection of the type indicates a fourth seta broken off each ramus. Furthermore, Menzies’ illustration lacks the simple setae present on the ventral surface of this appendage. The S. hanseni holotype is definitely a copulatory male as indicated by the form of the second pleopodal stylet, yet the antennular flagellum is described as having 10 articles, as opposed to approx- imately 16 on adult S. parallela males. This discrepancy may be real or is perhaps attributable to the difficulty of discerning whether or not flagellar articles are fused on a poorly preserved, decalcified specimen. The uropod illustrated by Menzies has fewer stout setae than that of S. parallela. Inspection of the uropod indicates that it has been compressed out of shape, such that setae could easily have been dislodged.
There have been no recent finds of S. capensis or S. hanseni, although much collecting has been done. We believe all of the above evidence strongly indicates the synonymy of these species with §. parallela.
Syneurycope heezeni Menzies, 1962 Figures 5 and 6
Synonymy.—Syneurycope heezeni Menzies, 1962, p. 151, Figs. 41A—E; Wolff, 1962, pp. 116-117.
Holotype.—L.G.O. Biotrawl No. 200 (55°42.9’S, 64°21.6’W); AMNH 12132, pre- paratory 2, 4.5 mm.
Paratype.—L.G.O. Biotrawl No. 200 ( 55°42.9’S, 64°21.6’W); AMNH 12133, @.
Other material.—L.G.O. Biotrawl No. 201 (55°31.6'S, 64°07.5’W); AMNH 12280, 2 22:1 2 anterior body fragment, | 2 midbody fragment. L.G.O. Biotrawl No. 220 (9°45.0’S, 34°24.0'W); AMNH 12281, 2. Present collection: 1969 Rankin Station No. 21, epibenthic sled (9 individuals); 2 preparatory 2° (no. 1 and no. 2) deposited at ZMUC.
Distribution.—Southwest Atlantic Ocean and Weddell Sea, 9°45.0’S to 73°52.0'S, 2288-3839 m.
Diagnosis.—Syneurycope with broad body; body length 4.1 (2) x tergal width of pereonite 2; body fringed laterally with numerous simple setae. Pleotelson contouring less complex than that of S. parallela: proximal ventral flanges less flaring, distal end less produced. Antenna I, @, first article wider than second, I/w 1.3; first 2 articles fused; first article much wider than second at their junction; second article inserts toward medial edge of first. Mandibular incisor process with 5 distinct teeth; molar process truncate with marginal row of setae. Maxillipedal epipod rounded distally. Pereopod V carpus |/w 2.7; dactylus paddle-shaped. Female operculum apical cleft
132
FiGuRE 5. Syneurycope heezeni holotype 2, L.G.O. Biotrawl 200 (AMNH 12132): A. cephalon-pereonite 1, dorsal view; C. body, lateral view, setae omitted from appendages, mouthfield simplified; F. pleotelson, ventral view, setae omitted from edge of operculum, right medial edge of pleotelson, and uropods, all setae are plumose. Preparatory 2 no. 2, 1969 Rankin station 21, epibenthic sled (ES): B. cephalon-pereonite 1, ventral view, right pereopod damaged. Preparatory 2 no. 1, 1969 Rankin station 21, ES: D. operculum, only bases of setae illustrated along left edge, all setae are plumose; E. left uropod, ventral view, in situ.
<'/; length of operculum. Uropodal endopod with 3 large apical setae and 3 stout lateral setae; exopod bears 2 apical setae.
Additional description.—Body length 2 4.4 mm, width 1.1 mm. Body widest at pereonite 2, preparatory @ I/w 0.5.
Remarks.—Syneurycope heezeni is readily distinguished from its congeners by the distinctly broader body; the unique antenna I peduncle (Fig. SA—C); and the setation of the uropodal endopod (Fig. 5E). It differs further from S. affinis by bearing a row of setae on the molar process of the mandible.
133
FIGURE 6. Syneurycope heezeni preparatory 2 no. 2, 1969 Rankin station 21, ES: A. left pereopod I, in situ. Preparatory 2 no. 1, 1969 Rankin station 21, ES: B. incisor process, mandible, plan view; C. lacinia mobilis, mandible, plan view; D. left mandible, setal row on distal edge of molar process not visible in this view; E. left maxilliped. Preparatory 2, holotype, L.G.O. Biotrawl 200 (AMNH 12132): F. left pereopod II, in situ; G. left pereopod III, in situ; H. left pereopod IV, in situ; I. dactylus, pereopod V, enlarged; J. left pereopod V, in situ, tip of dactylus omitted.
134
Menzies’ description and illustrations of S. heezeni are inadequate for modern requirements. We have therefore reillustrated it, drawing from both type-material and our working specimens, as circumstances dictated. For the most part, the original description refers to higher level characters. The fusion of the cephalon and first pe- reonite (Figs. 5A and 5C) is not unique to S. heezeni, but is diagnostic for the genus. The presence of a discrete first pleonal somite (Fig. SC) and the absence of maxillipedal coupling hooks (Figs. 5B, 6E) are features of the Syneurycopinae. Menzies (1962) cites the absence of an apical seta on the distal article of the mandibular palp, but it is so small that he probably overlooked it (Fig. 6D). The relative proportions of the uropodal rami are characteristic of the genus; a precise ratio is difficult to establish because of both insufficient standardization of measuring technique and true variability. The ap- proximate length ratio of exopod:endopod is 0.3 for the genus; Menzies cites 0.25 for S. heezeni, 0.20 for S. parallela, and 0.33 for S. hanseni; Birstein cites 0.33 for S. affinis. The available data indicate that the true ratio varies between 0.2 and 0.3 re- gardless of species.
The present revision is based on female specimens alone as males have not yet been collected.
Syneurycope affinis Birstein, 1970
Holotype.—Vityaz Station 5620 (44°48'N, 156°33’E): preparatory °, 4.8 mm.
Distribution.—Northwestern Pacific Ocean, 44°48’N, 5005—S045 m (known only from type-locality).
Diagnosis. —Syneurycope with narrow body; body length preparatory 2 ~4.6— 4.7x tergal width of pereonite 2. Pleotelson complexly contoured, similar to that of S. parallela. Antenna I @ first article subequal in width to second article. Mandibular incisor process 4-toothed; molar process large with ‘‘rounded anterior margin and a characteristically curved grinding surface’’; mandibular palp, °, lacking apical seta. Maxillipedal epipod rounded distally. Female operculum, apical cleft 4 the length of operculum. Uropodal endopod bears 5 marginal setae; exopod with a single apical seta.
Additional description.—Body length, preparatory 2, 4.8 mm, width | mm. Body widest at pereonite 2, preparatory @ I/w 0.5.
Remarks.—Syneurycope affinis appears to differ from its congeners by the char- acteristic form of the mandibular molar process, the number of incisor teeth, the ab- sence of an apical seta on the mandibular palp, the extent of the apical opercular cleft, and the setation of the uropod.
Birstein (1970) compares S. affinis to S. heezeni as the most similar Syneurycope species. Although we were unable to examine the holotype and sole specimen of S. affinis, from Birstein’s description and illustrations, we feel S. affinis more closely resembles the type-species for the genus, S. parallela Hansen. Both possess the nar- row, elongate body and the unmodified antenna I peduncle. Birstein cites ‘‘a constric- tion between the anterior and posterior halves of the body”’ as a unique feature of S. affinis. We have seen a similar condition on some S. parallela specimens and believe this to be an artifact of preservation. The most outstanding difference, as we see it, 1s the grinding surface on the molar process of the mandible. This condition of the molar process, as described by Birstein (1970), is previously unknown in the asellote isopods and deserves more study when additional material of S. affinis is collected. The other differences, listed above, are subtle ones and the examination of additional specimens may even obscure them when the ranges of morphological variability for these partic- ular characters are known.
Bellibos, gen. nov. Figures 7-13
Synonymy.—Syneurycope (pars.) Chardy, Menzies. Type-species.—Bellibos (Bellibos) buzwilsoni, gen. et sp. nov., Figs. 7-8.
135
FN ( SE a ) SSS SN Ty »
Imm ibe \ y,
Ficure 7. Bellibos (Bellibos) buzwilsoni, sp. nov., preparatory 2, WHOI 66: A. body, dorsal view; B. body, lateral view; C. cephalon-pereonite 2, ventral view; D. left uropod, ventral view, in situ; E. pleotelson, ventral view, uropods missing, long setae on operculum are plumose, semicircles indicate setae not illus- trated; F. operculum, setae on right distal edge omitted for clarity.
Distribution.—Eastern and western Atlantic Ocean, 50°43.4'N to 72°47.6’S, 2379- 4980 m.
Etymology.—bvellus, Latin, charming, pretty; bos, Latin, can be construed to mean “‘‘buffalo.”’
136
Diagnosis.—Syneurycopinae with body I/w usually <4.0. Combined length pere- onites 1-4 usually < pereonites S—7. Paired cephalic spines (=horns) present dorsally; cephalon demarked from first pereonite by a complete suture, articulation may be restricted. Topography of pleotelson simple; width tapers gradually from proximal to distal end. Antenna I 2 flagellum multiarticulate where known; I/w first article < 2.0. Female operculum widest midway or in distal half; rounded distally; median keel may be well developed. Pleopod I adult ¢ with outer ramus of distal end shorter than that of inner ramus. Adult 3d pleopod II exopod located at distal tip of protopod. Uropod with well-developed exopod where known, setation variable; length exopod at least 74 length endopod.
Remarks.—Bellibos species are identifiable by the presence of one or more pairs of cephalic spines, a complete suture line between the cephalon and pereonite 1, and a well-developed uropodal exopod. These characters will allow identification of the genus, although there is great morphological variability between congeners. Body shape varies from deep and robust to flat and fusiform; in one species the cephalon is greatly expanded and in another the first pereonite is expanded. These morphologies could have been as easily assigned to 4 monotypic genera; however the taxonomy would have become unnecessarily complicated without good purpose.
Within the genus, one species, Bellibos monicae, stands apart from all the rest. It is the sole exception to several otherwise firm diagnostic traits: its body I/w is almost always >4.0; the combined length of its pereonites 1-4 is > pereonites S—7; articulation at the cephalon-first pereonite border is reduced; its uropodal exopod is shorter than the endopod, whereas in all other species the rami are equal. In order to group the most similar species together, we have therefore created 2 subgenera: Bellibos, which includes B. buzwilsoni, B. dageti and B. multispina, and Bemerria for the single species, B. monicae.
Bellibos, subgen. nov. Figures 7-11
Type-species.—Bellibos (Bellibos) buzwilsoni, sp. nov., Figs. 7-8.
Distribution.—Eastern and western Atlantic Ocean, 50°43.4'N to 41°03.0’S, 2379- 4980 m.
Diagnosis.—Bellibos with combined length pereonites 1-4 < pereonites 5-7. Cephalon articulates freely with first pereonite. Uropodal rami equal in length where known.
Remarks.—Bellibos (Bellibos) includes 3 species: B. buzwilsoni, B. dageti and B. multispina.
Bellibos (Bellibos) buzwilsoni, sp. nov. Figures 7 and 8
Holotype.—WHOI Station 321 (50°12.3’N, 13°35.8’W): USNM, 173004, 6d, 4.5 mm.
Paratypes.—WHOI 321, preparatory ° fragment, USNM 173005; WHOI 321, im- mature 2, USNM 173006; WHOI 321, copulatory 6, ZMUC; WHOIT 321, preparatory EF TA MOSS
Other material.—Present collection. WHOI stations 64 (10 individuals), 66 (4); 155 (4); 156 (1); 195 (1); 245A (12); 287 (1); 321 (810); 328 (11); 330 (1). John Allen station 50 (28). Illustrated preparatory 2 (WHOI 66) and @ fragment (WHOI 66) USNM 173008 and 173007, respectively.
Distribution.—Eastern and western Atlantic Ocean, 50°43.4'N to 36°55.7'S, 2379- 4980 m.
Etymology.—In honor of our colleague, Mr. George (“‘Buz’’) Wilson.
Diagnosis.—Bellibos with deep, robust body; body length 3.1 (preparatory °), 3.9 (copulatory ¢) x tergal width of pereonite 2. Single pair of pointed cephalic horns present, without apical setae; cephalon not expanded in length dorsally relative to first
137
Ficure 8. Bellibos (Bellibos) buzwilsoni, sp. nov., copulatory 3, holotype, WHOI 321: A. left antenna I, in situ; C. left mandibular palp, in situ; M. pleopods I, damaged, distal end twisted; N. left pleopod II. Preparatory °, WHOI 66: B. molar process, mandible, enlarged view; D. lacinia mobilis, mandible, plan view; E. incisor process, mandible, plan view; F. left mandible, setae on molar process obscured in this view; G. left maxilliped, epipod detached. Preparatory 2, paratype, WHOI 321: H. left pereopod I, in situ, dactylus foreshortened; I. dactylus, pereopod I, true length. Nonpreparatory 2, paratype, WHOI 321: J. dactylus, right pereopod VI; K. long, slender plumose seta, typical of setae on pereopod V, carpus and propodus; L. left pereopod V, in situ, dactylus damaged.
138
pereonite. Dorsum of cephalon and pereonites 1-4 dense with simple setae. Pereonite 1 not embracing cephalon dorsolaterally. Pleotelson width at level of uropod insertion 34 that of proximal end. Antenna I, second article length about 1.5 that of first article; number of articles known to vary from 6 to 8 in preparatory @, 12 to 23 in copulatory 3. Mandibular incisor process with 6 teeth; palp apical article well developed in both sexes, number of setae varies from 6 to 16. Maxillipedal epipod short with blunt, rounded distal end; simple setae present on surface. Pereopods I-IV with undeveloped coxal plates; bases of unequal length: pereopods III and IV robust, ~3/5 length pereopod II; pereopod I more slender than pereopod II and 45 its length; pereopod II with row of stout setae along posterior margin of bases. Pereopod V carpus I/w 1.4. Female operculum pear-shaped; keel well developed, with setae; additional transverse row of extremely long, slender setae present on ventral surface just distal to end of keel. Male pleopod I well developed. Robust uropod with broad protopod and exopod; exopod approximately 1.5 endopod in width.
Additional description.—Body length 4.3-7.1 mm preparatory °, width 1.3 mm illustrated 2; body length copulatory 3 3.1-5.0 mm, width 1.1 mm holotype d. Pe- reonite 2 I/w 0.3 in adults of both sexes. Antenna I second article I/w <4.0.
Remarks.—Bellibos buzwilsoni is easily recognized by its single pair of cephalic horns, the dense setation on the anterior half of the body, the unequal lengths of pereopod bases I-IV, and its robust uropod. This species is well sampled in the Atlantic Ocean; in particular, WHOI station 321 yielded 186 whole-bodied individuals. (Our work was already in progress when this sample was received. For this reason, the illustrated and diagnosed female is not from the type locality.) Such a large sample size permitted analysis of the size-frequency distribution of postmarsupial developmental stages (Fig. 14) and the variability of key morphological characters (Table 2). Devel- opmental terminology follows Hessler (1970).
Size-frequency analysis indicates the presence of 3 manca stages; sex is undiffer- entiated in the first 2. Morphologically, manca | individuals are difficult to separate from the next stage. The anlage of pereopod VII is visible on manca 2 individuals; it can be developed to various degrees, presumably because the still soft limb continues to develop internally during the intermolt period. Manca 3 individuals possess a rudi- mentary seventh pereopod which varies from an unsegmented, wrinkled appendage to a partially segmented, firm limb. Sexes are now discernible: males exhibit rudimentary first pleopods, “%4—% the length of the opercular second pleopod; females possess an operculum of juvenile development, that is, with few setae and no keel. At least 2 more molts exist in males on morphological grounds, although the size-frequency anal- ysis is inconclusive. Juvenile males possess a first pleopod equal in length to the second, although the rami of the distal end of the now paired first pleopods are not yet fully developed, and the second pelopodal stylet is short and blunt. Copulatory males exhibit a well-developed pleopod I and an elongate, tapering second pleopodal stylet bearing a complete duct. The large size range of these stage 5 males indicates that there may be more than one instar. Although the data are insufficient, size-frequency analysis suggests the existence of 3 female juvenile stages. Juvenile 2 is poorly docu- mented, yet a consideration of likely instar size ranges indicates its existence. Mor- phologically, the first 2 stages are difficult to differentiate: juveniles | usually bear 2 setae whereas juveniles 2 bear approximately 5 setae on the apex of the opercular keel. Although the oostegites remain undeveloped in both stages, one of two juvenile 2 individuals has a distinct bud of tissue within its anterior coxae, presmably an oostegal anlage. In the third juvenile stage, the operculum is more heavily keeled and setose and preliminary oostegite buds are visible on the coxae of pereopods I-IV. There are 2 adult female stages: preparatory and brooding. Preparatory stage 7 females exhibit partially developed oostegites and a keeled, setiferous operculum. The 8 measured individuals range widely in size, suggesting that they reach the preparatory condition more than once in their lifetime, possibly alternating between the preparatory and brooding condition as seen in the Desmosomatidae (Hessler, 1970). Unfortunately, this hypothesis cannot be tested because no intact brooding females were sampled at this station.
139
TABLE 2. Range of variation of body length, number of articles in first antenna, number of setae on apical article of mandibular palp, and number of denticles on inner margin of fifth article of maxilliped is given for each of the apparent postmarsupial developmental stages, both ¢ and °, of Bellibos buzwilsoni. All specimens are from a single station, WHOI 321. See text for discussion.
Mean body
No. articles
No. setae apical article
No. denticles
fifth article
length + 1 SD antenna | mandibular palp maxilliped
Stage/sex N (mm) (left, right) (left, right) (left, right) Manca | 6 2 5 1.92 + 0.08 (5 7) (5-6, 6) (4, 4) Manca 2 6 2 60 2.40 + 0.09 @ag) (5—6, 5-6) (3-5, 3-5) Manca 3 6 15 DO ile O S01 (7-8, 7-8) (6-8, 6-8) (4-7, 4-6) Manca 3 @ 17 3.03 + 0.26 (CAD) (4-8, 6-7) (4-7, 4-6+) Juvenile 1 3 43 3.30 + 0.15 (9-12, 8-12) (5-9, 5-8) (5-7, 4-8) Juvenile | 2 21 3.53 + 0.14 (He 7) (0-11, 7-11) (5-10, 5-10) Copulatory 3 6 3.97 + 0.74 (12-23, 14-23) (9-15, 7-16) (6-9, 7-9+) Juvenile 2 2 2 4.20 + 0.00 (-, 7) (9-10, 9) (8-10, 7) Juvenile 3 2 5 5.55) 5.0513 (ea?) (10-11, 10-11) (9-10, 9-10) Preparatory 13 6.44 + 0.59 (6-8, 6-8) (6-12, 9-12) (9-12, 10-14)
The morphological characters studied for variability include the number of articles in the first antenna, the number of setae on the apical article of the mandibular palp, and the number of denticles on the fifth article of the maxilliped. These characters are frequently used in the syneurycopine literature, usually without regard to their varl- ability. The data are tabulated by stages in Table 2. The number of articles in the first antenna does not vary much in females from the earliest developmental stage to adult- hood: the number increases with development in males, as does the variability. The number of setae on the apical article of the mandibular palp varies with sex in most syneurycopine species; B. buzwilsoni is an exception because both sexes possess well- developed mandibular palps with numerous setae. The number of setae increases al- lometrically, with individual variation. Lastly, the number of denticles on the inner edge of the third article of the maxillipedal palp also varies both allometrically and individually (see Table 2). The wide range of values found for each of the above characters indicates the low value of these meristic characters in diagnosing syneu- rycopine species. We continue the practice of presenting meristic counts and morpho- logical measurements of single specimens in this paper because the sample sizes are usually too small to obtain significant ranges; one should regard the quoted value as a representative number, keeping in mind the potential for variability. However, in the diagnosis and additional description of B. buzwilsoni, we present the known range of a given character rather than a single type measurement because we have the variability data.
Characteristically, females are larger than the corresponding stage of males; the difference is amplified by increasing development. In both sexes, development pro- gresses gradually; the final size discrepancy of adults is then a result of the greater number of female instars and possibly greater incremental growth of females. The B. buzwilsoni illustrated preparatory female (Fig. 7) is far smaller than the average size of preparatory females at WHOI 321, suggesting the possibility of geographical vari- ation: WHOI 321 is in the northeastern Atlantic, the diagnosed female is from WHOI 66 on the Gay Head—Bermuda transect in the northwestern Atlantic Ocean. Two such distant populations, separated by the mid-Atlantic ridge may well diverge in certain characters.
Bellibos (Bellibos) dageti (Chardy), 1975 Figures 9 and 10
Synonymy.—Syneurycope dageti Chardy, 1975, pp. 695-698, Figs. 5-6. Holotype.—Campagne Biogas IV Station 2 (47°31'N, 9°09.7'W): missing from Na- tional Museum of Natural History, Paris; 2, 4.2 mm.
140
FiGuRE 9. Bellibos (Bellibos) dageti preparatory 2 no. 1, Allen 50: A. body, dorsal view; B. body, lateral view; D. pleotelson, ventral view, setae omitted from operculum and uropod, right uropod missing; E. left uropod, ventral view, in situ, exopod foreshortened; F. uropodal exopod, full length. Immature ¢ no. 3, Allen 50: C. cephalon-pereonite 1, ventral view.
141
Other material.—Present collection. WHOI stations 155 (6 individuals); 328 (31); 156 (7); 288 (4); 71 (1); 100 (1); 126 (12); 330 (2). J. Allen station 50 (21). Diagnosed preparatory 2 no. | (Allen 50) USNM 173009; illustrated preparatory 2 no. 2, im- mature d no. 3, copulatory d no. 4 (Allen 50) and copulatory d no. 5 (WHOI 328), USNM 173010, USNM 173012, USNM 173011, and USNM 173013, respectively; pre- paratory °, 6 fragment (WHOI 328) and juvenile 2 (J. Allen 50) deposited at ZMUC.
Distribution.—Eastern and western Atlantic Ocean, 50°43.4'N to 0°46.0'S, 2379- 4892 m.
Diagnosis.—Bellibos with flat, fusiform body; body length 3.8—4.1 (preparatory 2), 3.9 (copulatory 3) x tergal width of pereonite 2. Single pair of cephalic horns present, blunt-tipped and setose; cephalon not greatly expanded in length dorsally relative to first pereonite. Pereonite | embraces cephalon dorsolaterally; anterior edge fringed with simple setae. Pleotelson width at level of uropod insertion 2 that of proximal end. Antenna I, second article unusually elongate, up to 3 that of first, and setiferous; flagellum unknown. Mandibular incisor process may bear from 5 to 10 teeth; 2? palp with reduced apical article bearing single seta; apical article d palp well de- veloped with 8 setae. Maxilliped with numerous large, unequally bifid setae on ventral surface of basipodite and along outer distal edge of epipodite; epipod pointed distally. Pereopods I-IV with well-developed coxal plates, pointed anteriorly each with an apical seta; bases of subequal length. Unequally bifid setae present along posterior edge of pereopod I-IV bases and anterior edge of pereopod V—VII bases. Pereopod VI carpus I/w 1.6. Main part, 2 operculum oval; keel moderately developed with unequally bifid setae present along ridge. Pleopod I, ¢, outer ramus of distal end vestigial. Uropodal protopod elongate and slender; exopod subequal in width to en- dopod.
Additional description.—Body length 4.2-7.7 mm preparatory °, width 1.0-1.9 mm; body length copulatory ¢ 5.1 mm, width 1.3 mm. Body widest at pereonites 3 and 4. Pereonite 2 1/w 0.3 in adults of both sexes. Antenna I, second article I/w ~8.
Remarks.—Bellibos dageti is characterized by a combination of unique traits: blunt and setiferous cephalic horns; first pereonite which laterally embraces cephalon; unusually elongate second article of first antenna; anteriorly pointed, well-developed pereopod I-IV coxal plates; uropodal rami of equal width. The large natasome in combination with the flat, fusiform body shape is unique within the subfamily.
The species was first described by Chardy (1975) on the basis of a single female specimen; unfortunately, this holotype was apparently lost in transfer to the Paris Museum (P. Chardy, personal communication). This loss is a real misfortune because, although our specimens (85 individuals of both sexes from 9 North Atlantic localities, 3 of which are in the vicinity of the type-locality) are very similar to the illustrations and description of the holotype, a close comparison reveals problematical differences.
The holotype is said to possess a mandible with a globular incisor process bearing ‘*some ten denticles’’; our described specimen (preparatory 2 no. 1) bears 5 very distinct teeth. The holotype is 4.2 mm long and | mm wide at pereonite 4 (both mea- surements according to text of original description; use of scale line included with Chardy’s figure yields a length of 1.5 mm). Our specimen is 7.7 mm long and 1.9 mm wide, almost twice as large as the holotype. This discrepancy may be due to ontoge- netic variability. It is a preparatory female, but the maturity of the holotype is un- known. If the holotype is indeed an adult female, such a large size difference becomes as difficult to account for as the difference in the number of incisor teeth. These differences are not likely the result of geographical variability because both specimens come from the same ocean basin. The possibility exists that we are dealing with 2 discrete species characterized by size and the number of mandibular incisor teeth, but the reality of these differences is not well enough established to justify describing a new species at this time. Only one other difference was noted: the operculum of the holotype is illustrated without an apical cleft; all other syneurycopine specimens in- cluding the above specimen possess such a cleft. This character is, however, easily overlooked.
142
FiGuRE 10. Bellibos (Bellibos) dageti preparatory @ no. 2, Allen 50: A. incisor process, mandible, plan view: B. lacinia mobilis, mandible, plan view; C. left mandible, mandibular palp obscured in this view; E. left mandibular palp; F. tip of distal joint of right maxillipedal palp; G. left maxilliped, distal joint of palp damaged; H. left pereopod I, in situ; M. left pereopod VI, in situ, long setae are all plumose, basis slightly damaged. Preparatory 2 no. 1. Allen 50: I. plumose seta, enlarged view, typical of long, slender setae on operculum; J. operculum. Copulatory ¢ no. 5, WHOI 328: D. left mandibular palp. Copulatory male no. 4,
Allen 50: K. pleopods I; L. left pleopod II, long setae are plumose.
The species is redescribed and illustrated from specimens in our working collec- tion. From this material, it has been possible to describe a number of traits unrecorded in the original description, including the length of pereopod I-IV bases and the con- dition of males. Because there is no intact fifth pereopod on any of the mature speci-
143
Ficure 11. Bellibos (Bellibos) multispina nonpreparatory 2, allotype (AMNH 12094): A. body, dorsal view, posterior pereonites damaged; B. body, lateral view, posterior pereonites damaged; C. cephalon- pereonite 1, ventral view; D. pleotelson, ventral view, marginal setae of operculum and left medial edge not illustrated, uropods absent. Paratype ¢ (AMNH 12095): E. pleopods I, in situ. Holotype d (AMNH 12093): F. left pleopod II, in situ, all setae are plumose; G. left antenna I, in situ.
144
mens, the sixth is treated instead. Throughout the subfamily, the sixth pereopod is similar in shape to the fifth, although its dimensions are slighter.
Sexual dimorphism with respect to the antenna I flagellum remains unknown in B. dageti; the antenna is usually broken off at the junction between articles 2 and 3. However, the fact that the mandibular palp is sexually dimorphic suggests a parallel dimorphism for the first antenna.
Bellibos (Bellibos) multispina (Menzies), 1962 Figure 11
Synonymy.—Syneurycope multispina Menzies, 1962, pp. 151-153, Fig. 42E-K.
Holotype.—L.G.O. Biotrawl no. 52 (41°03’S, 07°49’E); AMNH 12093; 6, 4.3 mm. Specimen in poor condition; head detached from body; right antenna I and pleopod II present; no pereopods or mandibular palp.
Other material.—Female allotype, 4.2 mm, AMNH 12094: fair specimen with some cuticular damage; without oostegites; pereopods, antennae missing. Male para- type, AMNH 12095: specimen without pleotelson; pleopods I and single pleopod I present; no pereopods or mandibular palp.
Distribution.—Southeastern Atlantic Ocean, 41°03’S, 4960 metres (known only from type locality).
Diagnosis.—Bellibos with anteriorly deep, robust body; body length 3.6 (°, al- lotype), 3.4 (6, holotype) x tergal width of pereonite 2. Cephalon greatly expanded in length dorsally, at least 2x length pereonite 1; longitudinal row of spines present on either side of midline: anteriormost spines largest, decreasing in size posteriorly; num- ber of cephalic spines variable; each spine tipped with seta. Pereonite 1 not embracing cephalon dorsolaterally; pereonites 1-4 free of setae. Pleotelson width at level of uro- pod insertion ~%4 width at proximal end. Antenna I, second article <1.5 length first article, setae few; ¢ antenna I with ~25 articles, number unknown for 2. Female mandibular palp with robust apical article bearing 6 setae, unknown for ¢. Number of mandibular incisor teeth not recorded. Maxilliped with slender, simple setae: epipod unknown. Pereopods I-IV with undeveloped coxal plates; bases subequal in length, without stout setae; pereopods unknown beyond basis. Female operculum pear- shaped; moderately developed keel present with slender setae. Pleopod I, d, outer ramus of distal end well developed. Uropods unknown.
Additional description.—Body length 2 (allotype) 4.2 mm, width 1.2 mm; body length ¢ (holotype) 4.3 mm, width 1.3 mm. Body widest at pereonites 2 and 3; pe- reonite 2 I/w 0.3 6 and @. Antenna I, second article I/w <4.0.
Remarks.—The most distinctive feature of Bellibos multispina is the double row of spines on the dorsal surface of the expanded cephalon (Figs. 11A and 11B). The number of spines does not appear to be fixed for the species, as the 3 type-specimens all exhibit different numbers of spines. Furthermore, on any single specimen the num- ber of spines in the 2 rows need not be equal; the counts for the allotype, paratype, and the holotype are: 3L/5R, 4L/5R, 5L/6R, respectively (L = left, R = right).
This species is only known from the type-specimens. They comprise 2 adult males and 1 female whose maturity is difficult to ascertain because it does not possess oos- tegites. (Menzies incorrectly refers to 2 females and | male in the original description.) We have reillustrated certain views where helpful. The mandible and maxilliped, dis- sected presumably from the holotype and illustrated by Menzies, have been subse- quently lost; no further dissection of the type-material was attempted. Unfortunately, the pereopods and uropods remain unknown.
Bemerria, subgen. nov. Figures 12 and 13
Type species.—Bellibos (Bemerria) monicae (Chardy), 1975, pp. 698-701, Figs. 7-9.
145
Ficure 12. Bellibos (Bemerria) monicae preparatory 2°, WHOI 195: A. body, dorsal view: B. body, lateral view, setae omitted from appendages; C. left antenna I, lateral view, in situ; E. cephalon-pereonite 1, ventral view; F. operculum, setae omitted from left margin, all setae are plumose; G. pleotelson, ventral view, setae omitted from operculum, left medial edge of pleotelson and uropods, all setae are plumose. Copulatory ¢, WHOI 156: D. left antenna I, lateral view, in situ.
146
Ficure 13. Bellibos (Bemerria) monicae preparatory 2°, WHOI 195: A. left mandible; B. incisor process, mandible, plan view; C. lacinia mobilis, mandible, plan view; E. left mandibular palp; F. distal edge, max- illipedal endite, dorsal view; G. left maxilliped; H. left uropod, lateral view, in situ, endopod foreshortened; L. right pereopod V, in situ. Copulatory ¢, WHOI 156: D. left mandibular palp, in situ; I. pleopods I; J. left pleopod II. Preparatory 2, WHOI 72: K. left pereopod I, in situ.
Distribution.—Eastern and western Atlantic Ocean, 40°57'N to 72°47.6'S, 2864— 4270 m.
Etymology.—In the spirit of the holiday season, during which time the manuscript was completed.
Diagnosis.—Bellibos with combined length pereonites 1-4 > pereonites 5-7. Ar- ticulation between cephalon and first pereonite reduced. Uropodal exopod % to Ya length endopod.
147
Remarks.—Bemerria containing a single species, Bellibos (Bemerria) monicae (see ADDENDUM), Shares similarities not only with its congeners but with Syneurycope as well. It presents a morphology intermediate to the 2 genera. The elongate, slender body shape with the anterior 4 pereonites longer than the posterior 3 is a trait of Syneurycope. The reduced articulation between cephalon and first pereonite is only a step away from the complete fusion of these segments exhibited by Syneurycope. Bellibos monicae is the only member of Bellibos in which the uropodal exopod is shorter than the endopod; in Syneurycope, this condition is carried to an extreme. The setation of the uropodal exopod is reduced in Bemerria to 5 apical setae (the uropod illustrated in Fig. 13H is unusual in bearing only 3 exopodal setae; all other examined specimens bear 5 such setae); Syneurycope has only 2. Although the above traits suggest affinity to Syneurycope, Bemerria possesses more traits in common with Bel- libos: paired cephalic spines, a multiarticulated first antennal flagellum in both sexes, an expanded pereopod V carpus, a more pear-shaped female operculum, distal end of male pleopod I with shortened outer ramus, male pleopod II with a normally posi- tioned exopod. Furthermore, the fusion of pereonite | to the cephalon is a diagnostic trait of Syneurycope in this revision, clearly excluding B. monicae from Syneurycope. Although we choose to include this species with the 3 remaining syneurycopine species in Bellibos, the intermediate status of B. monicae justifies its isolation in a separate subgenus.
Bellibos (Bemerria) monicae (Chardy), 1975 Figures 12 and 13
Synonymy.—Syneurycope monicae (Chardy), 1975, pp. 698-701, Figs. 7-9.
Holotype.—Campagne Biacores station 245 (40°57'N, 22°16’W): missing from the National Museum of Natural History, Paris; d, 4.0 mm.
Other material.—Present collection. WHOI station 195 (2 individuals), 71 (16), 156 (2). Rankin station 1969 no. 23 (1). Illustrated preparatory 2 (WHOI 195) USNM 173015; illustrated copulatory ¢ (WHOI 156) USNM 173014; illustrated preparatory 2 (WHOI 72) USNM 173016; ¢ and preparatory 2? (WHOI 72) deposited at ZMUC.
Distribution.—See subgenus.
Diagnosis.—Bellibos with body length 4.5 (preparatory @), 3.8-4.8 (copulatory 3) xX tergal width of pereonite 2; anterior half of body deep. Single pair of cephalic horns present, tipped with an apical seta; transverse dorsal ridge poorly to well de- veloped at posterior edge of cephalon, may bear setae. Dorsal length, first pereonite approximately 1.5x that of pereonite 2. Antenna I with ~8 articles preparatory °, 19 articles copulatory 6. Mandibular incisor process bears a few main teeth and an in- distinctly serrated posterior edge; apical article of palp with ~4 setae in adult 2, up to 7 in adult ¢. Maxillipedal epipod narrow distally. Coxal plates undeveloped on pereopods I-IV; bases subequal in length. Pereopod V carpus I/w 1.4—1.5. Main part 2 operculum nearly round; keel poorly developed. Male pleopod I, outer ramus of distal end well developed. Uropedal exopod width ~!2 that of endopod.
Additional description.—Body length preparatory) 2 (WHOI 195) 3.7 mm, width 0.8 mm; body length copulatory 6 2.7—4.1 mm, width 0.6-1.1 mm. Body widest at pereonite 2; I/w 0.4 preparatory 2, 0.3-0.4 copulatory dé.
Remarks.—Bellibos (Bemerria) monicae is best characterized by the expanded first pereonite. Other traits which are unique to this species are: a uropodal exopod approximately % the length of the endopod; a cephalic ridge which can be developed to various extents. This species was originally diagnosed by Chardy (1975) on the basis of a single male individual taken from the northeastern Atlantic Ocean; unfortunately, this holotype specimen was also lost enroute to the Paris Museum (P. Chardy, personal communication). We have redescribed and illustrated the species from a collection of 21 individuals of both sexes which were sampled at 4 stations in the northwestern and southern Atlantic. Although these individuals closely resemble B. monicae, compari- son to Chardy’s literature description and illustrations of the holotype reveal some
148
Individuals
FAP inwo hl iat ee 0 va i ie i i a
of
MI
Number
20 30 40 5.0 60 © 8.0 Body Length (mm)
Figure 14. Size-frequency histogram of the postmarsupial developmental stages of Bellibos buzwilsoni from WHOI station 321. Stages are numbered separately for ¢ d and ? 2 and proceed from manca stage | (M1) through either preparatory 2, stage 7 (P,7) or copulatory d, stage 5 (C,5). Sexes are first differentiated morphologically at manca stage 3 (M3). See text for discussion. Abbreviations: C, copulatory; J, juvenile; M, manca; P, preparatory. Each unit on vertical frequency scale = 1 individual.
differences which must be considered. Chardy describes the cephalon as fused with the first thoracic segment, yet he illustrates a complete suture line between the 2 segments. Our specimens also exhibit a complete suture line between the cephalon and first pereonite (Figs. 12A and 12B), although the flexibility at this joint appears reduced due to the loss of the arthrodial membrane. In actuality, this joint may be nonfunc- tional, but the fusion of the 2 segments is not complete because a suture line still separates them. In contrast, Syneurycope demonstrates complete fusion of this joint.
The sculpturing on the cephalon and the shape of the expanded first pereonite also differ from Chardy’s description and illustration. The illustrated holotype lacks a ce- phalic ridge; a cephalic ridge may be poorly to well developed as a posterior contin- uation of the topography of the cephalic spines on our working specimens. The holo- type is illustrated with a central anterior projection of pereonite 1; this projection is not evident on our specimens.
We find it premature to diagnose another species on the basis of these differences. It is possible that the holotype possesses a poorly developed cephalic ridge, overlooked by Chardy; and the shape of the anterior edge of the first pereonite could be an artifact of artistic interpretation.
149
The dentition of the mandibular incisor process and lacinia mobilis of a represen- tative specimen from our collection may differ from the holotype. Chardy cites an incisor process with 4 teeth and lacinia mobilis with 3; our specimen exhibits a lacinia mobilis with the usual 4 teeth and at least 6 incisor teeth: 3 prominent ones followed by a posterior series of bumps which progressively diminish in size, the number of which is difficult to count. Although these could be diagnostic differences, the indistinct nature of the posterior edge of the incisor process, and the fact that Chardy’s illustra- tion shows 6 incisor teeth as opposed to the 4 that he cites in the description, make this difference suspect. Furthermore, the lacinia mobilis is illustrated by Chardy in side view, from which angle only 3 of the 4 teeth present would be visible anyway.
The male first pleopod of the holotype appears to differ from our illustration (see Fig. 131; Chardy, 1975, Fig. 9D), but the difference is largely a result of Chardy illus- rating the dorsal (inner) surface of the pleopod, while we illustrate the ventral (outer) surface.
The only remaining difference between Chardy’s specimen and ours is body size. The holotype is 4.1 mm long and 1.1 mm wide at pereonite 2; body I/w is 3.8; pereonite 2 I/w is 0.3. The copulatory male which we illustrate is only 2.7 mm long and 0.6 mm wide; body I/w is 4.8; pereonite 2 I/w is 0.4. Both specimens appear to be copulatory by the form of the first and second pleopods. The holotype is 12x larger than our specimen, the latter also appears more slender than the holotype. This size difference is perhaps the most difficult discrepancy to account for because size can be a diagnostic trait if consistent. Unfortunately, our collection (2 males) is too small to substantiate this difference.
Clearly, the loss of the B. monicae holotype has created a real problem. The species was described on the basis of a single male, without knowledge of the female or of individual variation. For this reason our samples are very important; they contain representatives of both sexes. The possibility exists that we are dealing with a new Atlantic species apart from Chardy’s, but the data are inconclusive. Should the holo- type ever be relocated, it would be a simple task to put this uncertainty to rest.
ADDENDUM
We have recently sampled Bellibos (Bemerria) in the Pacific Ocean. A single brooding female was collected in the eastern equatorial Pacific (9°25.3'N, 151°10.0'W) from a depth of 5175 metres. Although the specimen is damaged, preliminary examination indicates that it is indeed a new species, closely related to B. (B.) monicae. Its overall morphology, including the dorsally expanded first pereonite, resembles B. monicae closely. There is a suite of differences, though, that should prove diagnostic of the new Pacific species. The cephalon differs from that of B. monicae in several ways: the cephalic horns are smaller in relative size and they are placed further anteriorly on the cephalon; the cephalic ridge is lacking; the maxillipedal epipod is now short and distally rounded, as if to accommodate a change in the shape of the face. Other differences include a more pointed distal end on the pleotelson, a mandibular incisor process bearing some 9 teeth, and a uropodal exopod with 8 setae.
Unfortunately, we did not receive this specimen until our manuscript was nearing completion. Because the specimen is both damaged and a brooding female, we have set it aside until additional material is collected. The existence of a new Bellibos (Bemerria) species supports the taxonomic scheme presented herein.
Unlike the majority of our material, the Pacific specimen retains its third and fourth pereopods; they are extremely slender and elongate, of similar proportions to those of Syneurycope. This is a significant find, and indicates that the presence of extremely elongate pereopods III and IV is a diagnostic feature of Sy- neurycopinae.
ACKNOWLEDGMENTS
We thank H. L. Sanders and J. F. Grassle, Woods Hole Oceanographic Institution; J. A. Allen, University of Newcastle-upon-Tyne; and J. S. Rankin, University of Con- necticut for providing us with sample material. H. S. Feinberg, American Museum of Natural History, New York; B. F. Kensley, South African Museum, Cape Town; and T. Wolff, University Zoological Museum, University of Copenhagen, Denmark kindly made type specimens available for our examination. Pierre Chardy generously advised us on matters relating to the species that he described. G. D. Wilson and J. F. Sie-
150
benaller read and commented on the manuscript. This research was supported by National Science Foundation Grant DES 74-21506.
LITERATURE CITED
Barnard, K. H., 1920. Contributions to the crus- tacean fauna of South Africa. 6. Further ad- ditions to the list of marine Isopoda. Annals of the South African Museum 17:319-348.
Birstein, Ya. A., 1970. New Crustacea Isopoda from the Kurile-Kamchatka Trench area, pp. 308-356. In, Fauna of the Kurile-Kamchatka Trench and its environment, V. G. Bogorov (ed.), Vol. 86. Proceedings of the P. P. Shir- shov Institute of Oceanology, Academy of Sciences of the USSR, Moscow. (English translation: Israel Program for Scientific Translation, Jerusalem, 1972).
Chardy, P., 1975. Isopodes nouveaux des cam- pagnes Biacores et Biogas IV en Atlantique Nord. Bulletin du Muséum National d’ Histoire Naturelle, series 3(303):689-708.
Hansen, H. J., 1916. Crustacea Malacostraca, III. V. The order Isopoda. Danish Ingolf Expedi- tion, Copenhagen. 262 pp.
Hessler, R. R., 1970. The Desmosomatidae (Iso- poda, Asellota) of the Gay Head—Bermuda Transect. Bulletin of the Scripps Institution of Oceanography 15:1-185.
Hessler, R. R., and H. L. Sanders, 1967. Faunal diversity in the deep sea. Deep-Sea Research 14:65-78.
Hessler, R. R., and D. Thistle, 1975. On the place of origin of deep-sea isopods. Marine Biology 32:155-16S.
Menzies, R. J., 1956. New abyssal tropical Atlan- tic isopods with observations on their biology. American Museum Novitates 1798:1-16.
Menzies, R. J., 1962. The isopods of abyssal depths in the Atlantic Ocean. Abyssal Crus- tacea, Vema Research Series I:79-206. Co- lumbia University Press, New York.
Sanders, H. L., R. R. Hessler, and G. R. Hamp- son, 1965. An introduction to the study of deep-sea benthic faunal assemblages along the Gay Head-Bermuda Transect. Deep-Sea Re- search 12:845-867.
Wolff, T., 1962. The systematics and biology of bathyal and abyssal Isopoda (Asellota). Gala- thea Report 6:1—320.
Scripps Institution of Oceanography, A-002, Ja Jolla, California 92093 USA. (Present address for JAH: Marine Science Institute, University of California, Santa Barbara, % MRC Research Center, 533 Stevens Avenue, Suite E-40, Solana Beach, California
92075 USA.)
4a.
151
KEY TO KNOWN GENERA AND SPECIES OF SYNEURYCOPINAE
. Cephalic horns absent; cephalon fused to first pereonite; uropodal exopod
minute .—< 2) lenethrendoOpOdimccs sce a= ies eile Syneurycope spp. 2
_ One or more pairs of cephalic horns present; cephalon not fused to first
pereonite; uropodal exopod well developed, >’ length endopod......... RM ety Wan Ue cata A as ahh RSG Seva Sw) clete es Bellibos spp., gen. nov. 4
. Molar process of mandible curved, lacking setae, modified as a grinding
SIAC CL Sane eter ee oe Pao tates a cane oS aanaatetoke onde Syneurycope affinis Birstein
. Molar process of mandible truncate with marginal row of setae .............. 3 . Narrow body; pleotelson complexly contoured, surface topography exag-
gerated: antenna I, @, first article not expanded in width, not fused to second article; uropodal endopod with 2 large apical setae and 2 stout lateral SVETIAY SN py oe hap ila ens de ia me italian a ce ay ee Ceca gL re Syneurycope parallela Hansen
. Broad body; pleotelson contouring less complex; antenna I, °, first article
expanded in width relative to second, fused to second article; uropodal endopod with 3 large apical setae and 3 stout lateral setae............... re TREN ot EN WE GPA Foi Bere ote eevee IN Syneurycope heezeni Menzies Combined length of pereonites 1-4 > that of pereonites 5—7; uropodal ex- opod shorter than endopod; first pereonite expanded in length dorsally ... = 1 hm oce were Rt os SE SPR ed een PRE ane Bellibos (Bemerria) monicae (Chardy)
. Combined length of pereonites 1-4 < that of pereonites 5—7; uropodal rami
subequal in length; first pereonite not expanded dorsally ..............-. I eee R hy PE eee ers ete eval Soe pec svaneee onl - Bellibos (Bellibos) spp. 5
. Cephalon expanded in length dorsally; multiple paired horns on dorsal sur-
face olncephalonl giaae cass eee Bellibos (Bellibos) multispina (Menzies)
. Cephalon not expanded; single pair of cephalic horns ................+-+--+- 6 _ Flat, fusiform body; cephalic horns blunt, setose; pereonite 1 embraces
cephalon dorsolaterally; second article, first antenna unusually elongate, >2x length of first article; anteriorly pointed coxal plates present on pe- reopods I-IV; pereopod I-IV bases subequal in length; uropodal rami sub- Cqualeim: widthhieee ac ace ctor mer so sc Bellibos (Bellibos) dageti (Chardy)
. Robust, deep body; cephalic horns sharp, lacking apical setae; pereonite |
not embracing cephalon dorsolaterally; second article, first antenna <2x length first article; pereopodal coxal plates undeveloped; bases of pereopods III and IV substantially shorter than bases of pereopods I and II; uropodal exopod nearly twice the width of endopod..........--.....seeeeeeeeeee ERO TIG oei Roe arn one AE ane Saar ve aene ERE Bellibos (Bellibos) buzwilsoni, sp. nov.
NPE Napanee, ois Heel ail Tete) at08 nilishiee mp an eee Gyet S00 4K hen Sah i i. Ti ee iy? ees he les & . i (QQ, 06 © nee, alpha te ome eae ery ,' ah 2 5 Miiese Yu © eee rete Br, : ioe ra hp yes : age 7 4) TPE . Hira t Dee raw Gea “in } inden egenntied : aad
ade ote) 2 Vii aim ices
_ a emis) §6'8 val) how et
Lap <“oes) ig) elt ee a
im “> Cea, 9 iv ie Pprogiets Trey, I > al ho vipers
rie
~ ui pany =o) n 7 Aa een sh a a ee saaeiee P&) Yen! ~ of OR, |e oP uy
ee are es i rr wl. Seal ny iy a weu 7) ay AM, he Hwee \y :
fat we ove bh ney Lan, otiny
: ; rea hy Tee 77 aol L mi
; ca
alga ih eran ® Nes a ut
1rs eee Ui a” th” = i mn @ giigndy ips ME AMnvinee | ae Wye =v wi) ae Acal mpels., ie i my
“he tamu Oe | ey Whiten t 1 itt
wae oles nl > = oo tal 7 . Wy 17a ae ‘era wt - ‘elie Ol) 1a Bae 5 ee oR ie ah ite patatt FT ine |
- _ 7 . 2 a. eee
eos ay
a
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 11 pp. 153-167 12 December 1979
A new scalpellid (Cirripedia); a Mesozoic relic living near an abyssal hydrothermal spring*
William A. Newman
Abstract. A large stalked barnacle, Neolepas zevinae gen. et sp. nov., has been discovered living attached to ferriferous crust of a hydrothermal spring at 2600 metres on the crest of the East Pacific Rise. Comparisons with fossil and extant genera place the new genus as intermediate between the levels of organization found in Eolepas (Upper Triassic) and Calantica (Upper Jurassic—Holocene). Comparison with the ontogenetic stages of the advanced genus Pollicipes (? Upper Jurassic/lower Eocene—Holocene) indicates that Neolepas is represented by an 8-plated ontogenetic stage between the 6- and 13-plated stages of development. From these morphological and ontogenetic comparisons it is inferred that Neolepas represents the most primitive living scalpellid, a relic of Mesozoic age.
Habitat also favors the interpretation that Neolepas is a relic form, having found refuge near deep, hydrothermal springs. Such a refuge may have been attained in the late Mesozoic when predation pressures on sessile organisms are inferred to have dramatically increased. Though immigration into the hydrothermal environment by deep-sea stocks is a distinct possibility, in the present case, the route appears more likely to have been from relatively shallow waters of warm and tropical seas where tectonically active rifts intersect continental crust, and perhaps where islands are forming along ridge crests.
INTRODUCTION
Unusual environments are often inhabited by novel organisms and submarine hy- drothermal springs have proved no exception in this regard (see Corliss et al., 1979). Since the first photographs of animals from certain hydrothermal springs of the Gala- pagos Rift Zone became available several years ago, it was obvious that if barnacles were to be found there, they would likely be of some unusual type. Barnacles have exploited virtually all other marine environments, so it seemed likely that they would occur there. It was therefore especially exciting when a half dozen specimens of a most singular barnacle were recently recovered from a hydrothermal spring off central Mexico.
The specimens represent a new genus and species, Neolepas zevinae. Neolepas has important implications in interpretations of the evolution of the Scalpellidae. The Scalpellidae, the largest family of the Lepadomorpha, has recently been revised (Ze- vina 1978a, b). After the systematic position of Neolepas is established, it becomes possible to discuss the geologic time and evolutionary circumstances under which it or its immediate ancestors likely became adapted to the hydrothermal environment.
HABITAT AND BIOTA
The present material was taken from the crest of the East Pacific Rise off the west coast of Mexico. The general topography of the region has been documented by Nor- mark (1976). Francheteau et al. (1979) provide an artist's view of the porous sulfide edifices constructed by hydrothermal activity there. The sulfides were of predominantly zinc, copper and iron. Hydrothermal environments of submarine continental crust must
* Contribution of the Scripps Institution of Oceanography, new series.
154
vary widely in their chemistry (P. Lonsdale, personal communication). Oceanic hydro- thermal environments, conversely, although varying somewhat from spring to spring along a rift and from rift to rift, are likely quite similar in their characteristics. However, the very low concentrations of manganese at 21°N, as compared to the Galapagos situation, is notable (Francheteau et al., 1979) and this will be taken up below con- cerning metals of the hydrothermal environment and the barnacle. Corliss et al. (1979) summarize the situation surrounding the Galapagos Rift zone, a few thousand kilo- metres south of the Neolepas site:
‘‘Analyses of water samples from hydrothermal vents reveal that hydrothermal activity provides significant or dominant sources and sinks for several components of sea water; studies of conductive and convective heat transfer suggest that two-thirds of the heat lost from new oceanic lithosphere at the Galapagos Rift in the first million years may be vented from thermal springs, predominantly along the axial ridge within the rift valley. The vent areas are populated by animal communities. They appear to utilize chemosynthesis by sulfur-oxidizing bacteria to derive their entire energy supply from reactions between the seawater and the rocks at high temperatures, rather than photosynthesis.”
According to Corliss et al. (1979), the animals collected in the Galapagos Rift hydrothermal springs proved remarkable: clams resembling the unusual family Vesi- comyidae, mussels belonging to a new genus of Mytilidae, limpets of a new family, and pogonophorans of a new genus of Vestimentifera. A fish and crab peculiar to the area have also been observed. Some of these animals, such as the vestimentiferan, apparently have their closest relatives in deep water whereas others such as the true crabs hold their closest affinities with shallow water forms. Radiometric dating of shells from around an apparently expired vent suggested they were not more than 10 to 20 years old, indicating the minimum age of thermal activity at the spring was of the same order. Population structure differed from vent to vent, but individuals within a popu- lation were much the same size suggesting single colonizations in various vent areas (Corliss et al., 1979).
Vents are ephemeral and the exact locations of new ones unpredictable in space and time. But active rift zones persist for millions of years, and hydrothermal springs must have existed since the earth cooled sufficiently to allow the oceans to form; that is, before the origin of life. Therefore, other things being equal, species with adequate means of dispersal could persist indefinitely. But hydrothermal activity along rifts must at times shift more rapidly than can be compensated for by dispersal, and extensive extinctions have likely occurred. Furthermore, new forms must occasionally become adapted to the hydrothermal environment and such immigrations would, on occasion, cause extinctions through competition or predation.
It is important to attempt to determine the geological time an animal or its ancestor first became adapted to the hydrothermal environment. It is already apparent that the hydrothermal animals themselves are highly endemic, and therefore the geologic age at the generic level should be correspondingly great (Ekman, 1953). It will be instruc- tive to know the degree of endemic similarity between vent regions; if it is high, dispersal between vent regions is low and vice versa.
The barnacle described here is endemic at the generic level. But it is the first cirriped from a hydrothermal spring, so the problem of regional endemism cannot be addressed. On the other hand, the scalpellid barnacles have a fairly good fossil record (see Newman et al., 1969). Therefore, upon determining its systematic position, its probable geologic age can be inferred.
DESCRIPTION
Family SCALPELLIDAE Pilsbry, 1907:3 Subfamily LITHOTRYINAE Gruvel, 1905:8 & 96 (nom. correct. Zevina, 1978a: 1000, pro Lithotrynae Gruvel, 1905)
Diagnosis.—Scalpellids with 8 capitular plates (rostrum, carina, terga, scuta and one pair of latera); peduncle with numerous whorls of calcareous scales. Hitherto represented only by the genus Lithotrya.
155
FiGuRE |. Neolepas zevinae gen. et sp. nov.: The first paratype (British Museum; Nat. Hist.) reg. no. 1979-209. x2.5.
Neolepas gen. nov.
Diagnosis.—A lithotryine with fully developed capitular plates and strong, imbri- cating peduncular scales in whorls of more than 8, which, once developed, are retained throughout life. Type of the genus: N. zevinae sp. nov.
Neolepas zevinae sp. nov.
Diagnosis.—As for the genus.
Material.—Attached to ferriferous crust from near hydrothermal springs on the crest of the East Pacific Rise (20°50’N; 109°W) at a depth of 2600 m. ALV 915, rock- 4, 21 April 1979. Temperature freld estimated to be from near ambient (1.5°C) to 5°C (R. Ballard, personal communication).
Deposition of types.—Holotype, USNM Cat. No. 172581; first paratype, British Museum (Natural History) Reg. No. 1979-209; ontogenetic stages, USNM Cat. No. 172582.
Description.—A hermaphrodite resembling Pollicipes mitella (Linné) in form, but having a capitulum formed of but 8 plates homologous to those of Lithotrya (Fig. 1). The animal is intrinsically white, with the surface of the plates marked only by faint growth lines beneath a transparent cuticle.
The capitular plates, and especially the older peduncular scales which increase in age towards the point of attachment, are stained brownish red by a thin, ferroman- ganese deposit. The surface of the capitulum of the 2 largest specimens was covered with randomly spaced folliculinid cases which, preserved in 80% ethanol, were blue green.
The imbricating, triangular, projecting, spine-like peduncular scales form as min-
156
.ABCFG .1mm ,DEIJK .lmm LH .05 mm
J
UY Y fy YY A Win
Figure 2. Neolepas zevinae gen. et sp. nov.: Arthropodal structures of first paratype: A, cirrus I; B, cirrus Il; C, cirrus VI and caudal appendage; D, intermediate article of cirrus VI; E, caudal appendage enlarged; F, penis; G, labrum; H, crest of labrum; I, left mandible; J, cutting edge of right mandible; K, first maxilla.
iscule points in the growth zone immediately below the capitulum. These points grow longer and broader and become more projecting, as successive whorls are added. This process is the same as that described for scalpellids in general and is markedly different from the specialized situation in Lithotrya, where the scales are periodically shed (Darwin, 1851). In Neolepas, whorls so formed are somewhat irregular and difficult to follow around the circumference of the peduncle, but they appear to be composed of about 12 scales each in the paratype.
The 6 specimens ranged from approximately 3.5 to 58 mm in total length. In the
or
,A-C 1 mm
Figure 3. Neolepas zevinae gen. et sp. nov.: Juvenile stages in which the height of the capitulum exceeds the height of the peduncle (cf. Fig. 1).
3 smallest specimens the peduncle is less than half the height of the capitulum (Fig. 3). But this proportion reverses itself with further growth and in the paratype (Fig. 1) the peduncle is nearly twice, and in the holotype more than twice (41 to 17 mm), the height of the capitulum. This allometry accounts for the obvious addition of new peduncular scales compared to the less obvious growth increments in the capitular plates in the larger specimens. The result is that the capitulum comes to stand proportionately higher above the substratum with increasing age and, since the ovaries occupy the peduncle, there is more space for them. Placing the capitulum well above the substra- tum may be advantageous in insuring that the vital organs are well above the reach of some predators and that the trophic apparatus is in water of relatively undisturbed laminar flow.
The penis is well developed, the female genital apertures were observed at the bases of the first cirri and the holotype was brooding eggs. This indicates that the individuals are hermaphroditic. However, no complemental males were found between the occludent margins of the scuta, in the inner concave surface of the rostrum or, upon dissection, in the mantle cavity, and there are no pockets on the interior of the scuta. Thus the species appears to be purely hermaphroditic.
Trophi and cirri are designed for capture and manipulation of fine particles to an extraordinary degree (Fig. 2). The fragile nature of the cirri indicates that net casting must be extremely slow and then only into gentle currents.
The crest of the labrum, flanked by a pair of relatively small mandibular palps, bears a single row of minute, sharp teeth. The unique mandible is also provided with very fine denticles on the second and third tooth and along the very broad inferior angle. The combs formed by these fine teeth curve around onto the anterior surface of each mandible where they are in a position to scrape the crest and posterior (inner) surface of the labrum, as well as direct food pushed to them from behind by the maxillae, toward the mouth. Both the first and second pairs of maxillae are undistin- guished, other than being simple and clad with very fine setae.
The cirri are uncommonly long, beginning with the first and second pairs in which the distal portions of the rami are antenniform. The third cirri resemble the remaining pairs. The uniarticulate caudal appendages are small. Cirral counts are:
158
First paratype
I I] Ill IV Vv VI G.a ae 33 45 47 34 37 p 30 34 40 39 34 40 L2 24 33 ait 49 46 a7 I p 30 35 232 36 39 39 Holotype R23 31 35 47 34 38 60 I p 24 38 48 54 66 63 aig 700 36 47 56 255 54 p 28 34 50 58 159 260
Incubating eggs were found in the largest individual, as a single layer, in a pair of ovigerous lamellae of approximately 12 mm diameter. Each lamella was attached by a ‘‘Y’’-shaped ovigerous frena on either side of the mantle cavity, and contained ap- proximately 220 ellipsoidal eggs each measuring about 300 by 500 wm. Unfortunately, the eggs were at an early stage of development, and it could not be determined whether the larvae were to be released as nauplii or cyprids. If nauplii, it likely would have been possible to determine whether or not they would have been planktotrophic. Since this information is important in considerations of dispersal, it is regrettable that it was unavailable. But egg size in Neolepas is unusually large and this will be briefly con- sidered in the discussion.
,A-l i mm J 1mm
Na : A B
Ficure 4. Neolepas zevinae gen. et sp. nov.: Disarticulated capitular valves and a peduncular scale of a paratype (lateral views are of right side): A—C, frontal, lateral and cross-sectional views of rostrum; D-F, lateral view of scutum, median latus and tergum respectively; G—I, lateral, dorsal and cross-sectional views of carina; J, lateral view of a peduncular scale.
The genus has been named Neolepas: Neo—Greek neos (recent) + lepas—Greek lepas (shellfish); a Recent (Holocene) form inferred to have stemmed from an ancient
159
(Eolepas/Archaeolepas) \epadomorph lineage. The species has been named for Dr. Galina B. Zevina, in appreciation of her numerous contributions to our knowledge of the thoracican cirripeds, and especially for her recent revision of the living Scalpellidae (1978a, b).
DISCUSSION Affinities
If one takes the structural data at face value, Neolepas must be assigned to the previously monotypic subfamily Lithotryinae. Lithotrya then is its closest relative and several species are found inhabiting primarily intertidal limestone in the western At- lantic and Indo-West Pacific. Lithotrya encompasses the only burrowing thoracican cirripeds, but this habitat alone is hardly grounds for erecting a new genus for the new form from the hydrothermal spring; there are a number of important structural differ- ences.
Lithotrya is specialized for burrowing, as deduced by Darwin (1851). These spe- cializations include (1) reduction of the rostrum and to some extent the single pair of latera, sometimes to mere rudiments, since the rostrum is no longer needed to protect the basal portion of the occludent scutal margin and the latera have become involved in forming, with the carina and terga, a plug in the burrow when the animal is with- drawn; (2) dimorphism in the peduncular scales, those surrounding the base of the capitulum being larger than those clothing the bulk of the peduncle; (3) small size and low profile of peduncular scales, forming a many-faceted calcitic grinding surface to attach primarily aragonitic limestone (chemical dissolution in burrowing may also be involved); (4) secretion of a calcareous cup or pad of cement attaching the animal near the base of the burrow; and (5) periodic molting and replacement of the peduncular cuticle and scales that totally replaces the grinding surface, a process unique to Lith- otrya.
These characters readily separate Lithotrya from Neolepas at the generic level, but they do not preclude the two genera being in the same subfamily. The distinguishing features of Lithotrya are specializations to burrowing that are readily derivable from a Neolepas-like ancestor.
Position of the Lithotryinae
Broch (1922), without an appropriate explanation, placed Lithotrya as a derivative of the higher pollicipoid, Protomitella. This would require its being a reduced form having lost at least the subcarina and supplementary whorl of capitular plates. Broch, following Pilsbry (1908), was very much concerned with the structure and distribution of males among the scalpellids and came to the conclusion that they were absent in all higher forms. Males are absent in Lithotrya and this automatically made it a higher form. But the value of males in ranking genera is dubious since in the genus /bla alone there is a pure hermaphrodite, a hermaphodite with complemental males and a species in which the female is accompanied by dwarf males. Furthermore, it has been discov- ered that complemental males are even found in certain relatively advanced balano- morph barnacles (McLaughlin and Henry, 1972).
Zevina (1978a) places the Lithotryinae as the first subfamily of the Scalpellidae in her important revision of the extant members of this family. She arranges the remaining genera essentially in ascending phylogenetic order of increasing complexity according to the criteria set forth by Drushchiis and Zevina (1969). Foster (1978) independently came to the same conclusion and places Lithotrya at the stem of scalpellid evolution as far as living genera are concerned. However, in the second part of her revision of the scalpellids (Zevina, 19785), apparently for the same reasons as Broch (1922), she places the Calanticinae rather than the Lithotryinae at the stem of her phylogenetic LECE,.
Broch (1922) took the fossil record into account in drawing phylogenetic conclu- sions, and he championed the fundamental nature of the 5 ontogenetically chitinous,
160
primordial valves in cirriped evolution. However, the rather simple forms, Cyprilepas (Wills, 1963) with its bivalved chitinous carapace, Praelepas (Chernyshev, 1930) with its 5 chitinous valves and Eolepas (Withers, 1928) with its rostrum, had yet to be discovered. And, at the time, it was not realized that the Paleozoic Machareidia, with their numerous whorls of calcareous imbricating plates, were not barnacles (Withers, 1928). Furthermore, neither Broch (1922) nor Zevina (1978a, b) drew upon the onto- genetic data in Pollicipes that Broch (1922) had so carefully described and Drushchits and Zevina (1969) had recognized as important, in drawing phylogenetic inferences. Finally, neither Broch nor Zevina had Neolepas to ponder. What bearing then does fossil and ontogenetic evidence have in determining the position of the Lithotryinae in the evolution of the Scalpellidae?
Fossil and Ontogenetic Evidence
Pollicipes is considered the most advanced of the generalized members of the pollicipoid Scalpellidae (Broch, 1922; Zevina, 1978b), and the postlarval ontogenetic stages in extant Pollicipes polymerus Sowerby are described by Broch (1922). It is remarkable to observe that there is virtually a one-for-one correspondence between the appearance of fossil cirripeds through time and this ontogenetic sequence. Only the ‘‘Neolepas or 8-plated stage,’’ recapitulated in the ontogeny of Pollicipes, is miss- ing from the fossil record. By placing Neolepas in the open position (Fig. 5), we should be able to infer the geologic age of the Neolepas grade of evolution with considerable confidence, even though it is only known from the Holocene.
Figure 5 has been prepared to aid in the comparison between the extant and fossil genera involved here, and in visualizing their alignment with the ontogenetic stages in Pollicipes. The oldest fossil evidence for the Cirripedia is found in the Silurian lepad- omorph Cyprilepas (Wills, 1963). However, the lepadomorphs descended from free- living ancestors at an ascothoracican level of organization (Newman et al., 1969; New- man, 1974). Unfortunately ascothoracicans are known only as far back as the Creta- ceous, and then by fossil traces made by the more specialized wholly parasitic type, like Ulophysema (Madsen and Wolff, 1965). But one cannot distinguish the bivalved carapace of generalized ascothoracicans from some forms referred to the archaeocopid ostracods (Lower Cambrian—?Lower Ordovician; Sylvester-Bradley, 1961). Therefore, because the ascothoracican level of organization cannot have been less than Silurian, and because fossils that could represent them have been found in the Cambrian, the latter age is inferred here. The important point for present purposes is, however, that the ancestral free-living form, represented for the most part by the generalized char- acteristics of an extant ascothoracican such as Synagoga, is passed through in the ontogeny of all cirripeds as the cyprid stage, as illustrated in Fig. 5.
The cyprid larva, when first attached to the substratum, can be considered rep- resentative of the ‘‘Cyprilepas stage’’ in the evolution of barnacles as well as in the ontogeny of Pollicipes, because it is the closest living approximation of that level of organization in all cirripeds above the Ascothoracica. Indeed, if an attached cyprid capable of feeding and reproduction were found, and there were no contrary evidence, it should be assigned to the Silurian family Cyprilepadidae.
The next, or what can be referred to as the ‘‘Praelepas stage’ in the ontogeny of Pollicipes, has the formerly bivalved carapace divided up into 5 plates; the paired terga and scuta of each side and the carina protecting the dorsal articulation. At this stage, all 5 plates are of a prismatic chitinous construction; the so-called primordial valves of Darwin (1851:22). The bivalved carapace of Cyprilepas is prismatic chitin (Wills, 1963), and this is the condition in the 5-plated stage in the ontogeny of higher cirripeds (Lepadomorpha and Verrucomorpha; Darwin, 1851).
While Praelepas of the Carboniferous retained chitinous valves throughout life, and the peduncle was unarmored (Schram, 1975), in extant 5-plated lepadiform bar- nacles (Oxynaspis, Lepas, Poecilasma, etc.), these same plates are calcified. Darwin (1851) noted that Oxynaspis, with its tendency to form subcentral scutal and carinal
Jeniide) exe) padiuid JUNXa pue jURIXa 0} paredWoOd *(
161
(SS1LV1d SYOW YO £1) d3S00V
G300V STYOHM — |VYSLV) TWNOILIGOV|(SSLV1d 8) GS00V\(S31V1d 9) G3dGGV| (S3LV1Id S) 3OVLS |(S39VLS ASLVId 2)
(S31V1d 2)
‘PaLajul aq UPD IBUIAOYINT] IY} 1OJ ade Sisseing e ‘Auaso[Ayd oy) WOIy ‘aduanbas sNauUasojAyd ay) YUM auapuodsasios yied 104 Jed & sey AUaTO]UO
T7761) YOOAG AQ paqudsap se ‘(QuUIT) SH4aUAjOd SadiojOg Jo Auaszo\uo ayy, “¢ ANNOY
SAMI [Od Ni NOILVZINVOYO YVAINLIdVO
AYVLNSW31ddNS| 8 YNINVOSNS |VY3LV7 40 Ylvd 3NOINNYLSOY G3ISIOIVD] SATWA WIGHOWIYd|GINdAD GSHOVLIV] wWAeWT alddAd |4O ANSSOLNO
SNOSOVL3AYO dISSVYENL
F SNOSOVLIYO 1 Svl¥l N é)3N3003° oIssvYNnr Nn -OISSVIYL
wy
$0d9/0380YI/p
SNOY34INO8YVo
NVIMSWVON & ‘NVIYNTIS<
NVIYNTIS | SNOSIVL3IY9
\ Ns / Nie
>)
B soda/07 SOd3/9D4/q
$0d3/09/\/ ‘248 SOMIIW/OF ‘O48 DIYUD/OD Q DAYOY{IT
S1S31 GIONIHD3 NI SMOYNNE AG
@
49 s0da7 ‘siasouAxQ
SVNidIOIT1Od | SVNIOILNV1V9} SVNIAMLOHLIT | = ATIWVIENS ON ‘O49
Luvd NI“SYOITISd WOS dlOd!9I110d
Luvd NI “SNVOIOVYOHL
"Svaldvd313Ved 3YOICIdSVNAXO 3vdldvds 1
HdYOWOCVdS |
soda/4s0h9 | (4, owastydo/fp
‘aya DB0bDUAS SV GIGVd3d WHdAD] VOIOVYOHLOOSV
Q3YYSSNI
NMON®™ ED), SIPS OMOED,
SWYOS ASSO S| YO / ONV LONILXS
VY SN 39 INVLX4
162
umbones, was intermediate between lepadiforms and scalpelliforms. It is noteworthy that in Praelepas the carinal umbo is already apical in position, as it is in all generalized scalpellids.
The next, or ‘‘Eolepas stage’ in the ontogeny of Pollicipes, corresponds to the oldest fossil scalpellid, Eolepas. In this stage the calcareous rostrum has been added, bringing the number of capitular plates to 6. The lack of a chitinous primordium for the rostrum led Broch (1922) to consider the 5 chitinous valves as the primitive con- dition, a view subsequently substantiated from the fossil record by Praelepas.
The Eolepas/Archaeolepas level of organization, which spanned most of the Me- sozoic, included a peduncle armed with calcified denticles. It is from peduncular den- ticles that the additional capitular valves were phylogenetically derived. The capitular organization of Eolepas is passed through in the ontogeny of Pollicipes, but the pe- duncle at this stage is unarmored.
In the next or ‘“‘Neolepas stage’’ in the ontogeny of Pollicipes, a pair of median lateral plates is added. This brings the capitular count to 8. There are no recognized fossil representatives of this 8-plated stage, but the Neolepas level of capitular organi- zation fills the gap between the Eolepas (6-plated) and the Calantica (13-plated) stages in ontogeny.
In the next, or ‘‘Calantica stage,’ in the ontogeny of Pollicipes, a subcarina and 2 pairs of latera have been added thereby duplicating the level of organization in scalpellids reached in the late Mesozoic, a level that has persisted into the Holocene in members of the Calanticinae (Zevina, 1978; Foster, 1978). Many elaborate variations occurred, but no forms representing them survived much beyond the Jurassic or Cre- taceous (Newman et al., 1969; Hatton, 1977).
The addition of one or more whorls of numerous small plates around the base of the capitulum completes the ontogeny of Pollicipes. This level of organization is known from the fossil record with certainty from the lower Eocene, but it is likely to have been achieved at least by the Cretaceous. Some populations of Pollicipes persisted as dominant high intertidal lepadomorphs in the eastern Atlantic, eastern Pacific and Indo- West Pacific today, although Foster (1978) points out that the last species, P. mitella, is quite distinct from Calantica and Pollicipes and should be assigned to the genus Capitulum Gray, as proposed by Withers (1928). This is very interesting because Ca- pitulum could readily be derived from Neolepas by the elevation of a single whorl of peduncular scales to the capitulum.
Comparing the orderly increase in capitular complexity, in the evolution of the lepadomorphs, with the ontogentic stages in the postlarval development of Pollicipes, supports the decision to insert the Neolepas level of organization between that of Eolepas and Calantica. The Neolepas stage is also seen following the Eolepas stage in the ontogeny of some species of Calantica described by Foster (1978).
The purpose of the aforegoing exercise has been to interpret the phylogenetic position of the Lithotryinae in the Scalpellidae and thereby to estimate the probable age of the Neolepas level of organization, because it may have no counterpart known in the fossil record. Placing Neolepas in the open position between the Eolepas and Calantica levels of organization in the fossil sequence, allows one to infer an age for the Lithotryinae of at least Jurassic. However, there are specimens referred to Blas- tolepas orlovi Drushchits and Zevina, described by the same authors (1969; figs. 2d (128/11 and 4 (128/15)) from an ammonite from the Lower Cretaceous of the northern Caucasus, that appear to be a lithotryine since they are figured as lacking the carinal latus and subcarina of stramentines such as Blastolepas. Drushchits and Zevina infer that these specimens are ontogenetic stages of Blastolepas, but the peduncular scales are already formed. Therefore it is very unlikely that they are an ontogenetic stage because addition of plates to the capitulum after the peduncular scales have appeared, is unknown in extant scalpelliforms. If, upon reexamination of this material, it turns out that the carinal latus and subcarina are actually lacking, the existence of the Lith- otryinae in the Lower Cretaceous would appear to have been established. The new
163
form would be neither Lithotrya nor Neolepas because the peduncular whorls are each composed of but 8 plates, as in the archaeolepadidine Archaeolepas and the stramen- tines Stramentum, Loricula, Squama and Blastolepas.
Specter of Progenesis
A well-preserved ontogenetic sequence has its pitfalls in drawing inferences con- cerning progressive evolution because there is the possibility of regressive evolution in the form of paedomorphosis (progenesis; Gould, 1977). In the present case, Polli- cipes could conceivably retrogress to the Eolepas level of capitular organization, be- cause it is at this stage in its ontogeny that cirral feeding begins. This is more than far enough back for present purposes because it is a stage below the level of Neolepas. Thus, the Neolepas level of organization could be achieved through progenesis. Was it?
The capitular and peduncular armament of Neolepas is fully developed. All capit- ular plates are fully approximate and as heavy in construction as in any shallow water or intertidal scalpellid, and much more so than in any abyssal scalpellid. The carina guards the entire dorsal region, from the base to the occludent portion of the tergal margin, and the rostrum does likewise up to the occludent portion of the scutal margin. The large latera fully guard the basal junction between the scuta and terga, where the capitulum joins the peduncle. Peduncular scales fit as closely as possible around the base of the capitulum, in the peduncular growth region, and as successive whorls enlarge as the capitulum moves upwards, they immediately take on a strongly spined imbricating form. All available plates are arranged to optimize fully their protective capabilities and there are no indications that any have been lost in the optimization process. There is no evidence then to suggest that Neolepas is progenetic.
This is in contrast to the situation in Lithotrya whose identical capitular organi- zation shows retrogression in the rudimentary nature of the rostrum and latera. The cause of the retrogression is its adaptations to burrowing. However, retrogression in some plates leads to the distinct possibility of loss of others in this genus, and a study of its ontogenetic stages might shed some light on the matter. But there is presently no evidence that Lithotrya has lost any capitular plates, as far.as adult morphology is concerned, and I can only conclude that Lithotrya has descended from a pre-Calantica, Neolepas-like form.
The dwarf, parasitic males of Calantica are another matter (see descriptions by Foster, 1978) because many progress no further than the Eolepas or Neolepas onto- genetic stage. But their capitular plates are barely approximate and their peduncles are scaleless, all of which suggests that progenesis is responsible for their reduced form.
In the final analysis, there is no way of proving whether or not Lithotryinae con- sists of progenetic forms. Even the discovery of a fossil of a Neolepas-like species of the appropriate geologic age would not be proof of the matter. But all the evidence we do have strongly favors the conclusion that Lithotrya and Neolepas are relics of a late Mesozoic radiation.
EGG SIZE, SEASONALITY AND RECRUITMENT
Barnes and Barnes (1968) have noted that the number of eggs produced by bar- nacles is in good part a function of individual size, that frequency of brood production is apparently greatest under optimal conditions and that size of eggs appears to de- crease with decreasing latitude. These generalities are based mainly on high and mid- latitude species having planktotrophic nauplius larvae. They have been correlated pri- marily with the parceling of adult metabolic resources to larvae and the productivity of the waters into which they will be released, particularly along latitudinal gradients. No consideration has been made of the broader issues of biogeography concerned with differences in dispersal requirements for continental, insular and pelagic species. Fur- thermore, no attention has been paid to deep-sea barnacle species, other than to note
164
that deep-sea barnacles generally hatch as cyprids (Hoek, 1883; Newman and Ross, 1971). Any correlation between what has been observed in Neolepas with what is known in cirripeds in general will be tenuous at best because all we have to work with is the number and size of eggs from a single brood taken from the largest specimen and the range in size of juveniles in the single sample.
In a recent paper, Achituv and Barnes (1978) tout the eggs of a western Indian Ocean intertidal species, Tetraclita rufotincta (Pilsbry), as being exceptionally large. They are nearly 19x the volume of those of other species of Tetraclita (a subtropical/ tropical genus), and >3.5x that of relatively high latitude forms such as Balanus balanus (Linné) and Semibalanus balanoides (Linné). The eggs of 7. rufotincta are ellipsoids, as cirriped eggs usually are. They measure about 464 by 316 wm when first laid and 477 by 362 wm when eyed or approaching hatching. It appears that the nauplii of T. rufotincta are planktotrophic (Y. Achituv, personal communication).
The newly laid eggs of Neolepas measured approximately 500 by 300 wm. There- fore Neolepas is comparable to T. rufotincta in having exceptionally large eggs. Num- ber of eggs per brood is not comparable, however, and we know neither the form nor the trophic capabilities of the larva that hatches. Achituv and Barnes (1978) report the number of eggs per brood in 7. rufotincta over a wide range of sizes. The count increases from approximately 1000 per brood in the smallest individuals to nearly an order of magnitude more in the largest. The number of eggs in the largest and only specimen of Neolepas having them was approximately 440, half that of the smallest T. rufotincta. However, T. rufotincta, at least on the shores of Elat, has a breeding season of but 2 months a year. It is therefore tempting to suggest that breeding in Neolepas is likely seasonless, as has been noted in some other deep-sea invertebrates (Rokop, 1974). By producing numerous broods per year Neolepas would be in a po- sition to make up for its relatively small clutch size.
That larval availability is continuous throughout the year is strongly supported by the wide range of sizes (3.5 to 58 mm high) observed in the single sample of 6 specimens of Neolepas. Recruitment must be, if not continuous, at least over a long period of time. This is contrary to the conclusion reached by Corliss et al. (1979) who, because of the distinctly different populations of uniformly sized individuals at different vents, suggested that colonization was often effectively a single event. This may be the case for some of the community dominants, but it does not appear to be so for Neolepas.
It is important to note that 7. rufotincta, in addition to producing large eggs, Is also unusual for a Tetraclita in being distributed on numerous islands of the western Indian Ocean as well as continental shores. Large eggs in this case, and consequently large larvae, may be an adaptation to long-range dispersal, rather than simply to rel- atively sterile tropical waters as suggested by Achituv and Barnes (1978). If so, this may be in good part the explanation for the exceptionally large egg size in Neolepas whose ‘‘islands’’ are apparently hydrothermal springs.
NEOLEPAS AND THE HYDROTHERMAL ENVIRONMENT Immigration into Hydrothermal Environments
An interesting question concerns how species or their ancestors first became adapted to the hydrothermal regime. It seems there are but 2 possibilities: (1) they either entered from shallow water in situations such as where islands are forming along ridge crests and rift zones intersect continental crust. Under such conditions they could first become adapted to the hydrothermal environment and then to the deep sea, or (2) they have been derived from deep-sea forms that became further adapted to the hydrothermal regime. The first option is the most parsimonious because there is a greater diversity of relatively eurytopic forms in shallow water to choose from and, in terms of gradients, the transition is less severe. But the deep-sea route is open and it is unlikely that nothing has taken advantage of it.
The new barnacle, Neolepas, is a scalpellid and the pollicipoid section of the family (Lithotryinae, Calanticinae and Pollicipinae; Zevina, 1978) is represented by 9
165
extant genera. Although 5 of these are exclusively intertidal or shallow water, 3 have wide bathymetric ranges, from less than 500 metres into abyssal depths (Zevina, 1978a). However, the latter are at a higher level of organization than the Lithotryinae. Therefore, because Lithotrya is intertidal and was likely derived from a shallow-water form comparable to Neolepas, it seems most probably that Neolepas was derived from a shallow-water lithotryine radiation of which Lithotrya is the sole surviving shallow-water representative.
Lithotrya, in inhabiting intertidal limestone in the western Atlantic and Indo-West Pacific, and in having no surviving shallow-water relatives, is apparently a relic that has escaped predation pressures of the reef environment by burrowing (Newman, 1960). This view, that Lithotrya is a relic, is shared with Foster (1978:122) who wrote: ‘The tropical rock-boring genus Lithotrya may .. . be an intertidal refugee of early scalpellid evolution, finding protection by boring into coral boulders. The few capitular plates . . . in addition to the basic five, may be a pre-pollicipoid condition in scalpellid evolution.’ Interestingly, appropriate predation pressures are inferred to have dra- matically increased in the late Mesozoic (Vermeij, 1977), a time when the lithotryines are inferred to have evolved from the now wholly extinct Eolepas level or organization. It seems likely that it was during this late Mesozoic revolution that Lithotrya found its refugium in burrowing and Neolepas found refuge near hydrothermal springs in rela- tively shallow water.
Neolepas and some Metals of the Hydrothermal Environment
Rock-5, the substratum from which the sample of specimens of Neolepas was taken, was not clearly associated with an active hydrothermal vent. Unfortunately, there are no temperature data for this particular site, but the temperature field was estimated to range from near ambient (1.5°C) to as high as 5°C (R. Ballard, personal communication). The rock itself consisted of a clump of thickly encrusted empty worm tubes. The crust, at least that to which the largest barnacles were attached, proved to be a ferriferous deposit having a metallic composition of Fe, Si, Ca, Mn and Mg, in order of decreasing abundance. Aluminum was nearly equal in relative concentration to Mg, but Na, P, K, Cu and Zn were in trace amounts (Analytical Facility, SIO: Cambridge [S-4] SEM and Ortec Energy Dispersive X-ray Analyzer). The deposition of largely Fe rather than other metals such as Zn and Cu would be expected at the cooler end of the hydrothermal spectrum (R. Ballard, personal communication).
A similar appearing deposit was already noted as occurring on the shell of the barnacles, there being more on the older than the younger parts. The peduncular scales are particularly appropriate in this regard because they are graded in age. A series of scales was therefore sampled for SEM/X-ray analysis. A single scale was taken at intervals of 1 cm along the holotype specimen, beginning in the growth zone just below the capitulum and ending near the point of attachment to the substratum. The first scale, from the growth zone and. therefore the youngest in the series, had a composition of Ca, S and Si, P and Fe, 5 of the 8 elements analyzed for. Iron moved up in relative concentration over the next 3 (older) intervals. Interestingly Mn appeared and then increased along with Fe so that the metallic composition of the crust on the older scales was commonly Fe, Mn, Ca, Si and Mg; a ferromanganese deposit. As noted above and by Francheteau et al. (1979), Mn is in relatively low abundances at 21°N. The high concentrations that develop on the scales of Neolepas are therefore curious. They may be due to bacterial activity because the scales of Neolepas are calcite (J. Hawkins, personal communication) and it has recently been demonstrated that calcite is required for Mn oxidation by pure cultures of marine bacteria (Nealson and Ford, in press).
The barnacles were being incrusted with ferromanganese deposits rather than salts or oxides rich in Zn and Cu reported from the high end of the hydrothermal temperature spectrum. Therefore the chemistry of the animals themselves was examined. Three samples were taken from the holotype of Neolepas—the left scutum (not destroyed in
166
the process), the scutal adductor muscle and a slice of the prosomal region including a portion of the digestive gland. These same structures were also sampled from Pol- licipes polymerus, a local intertidal relative of Neolepas. While scanning for metals, the proportions of Mg, and S to Ca were determined. The two species were quite similar except that Mg was higher in Neolepas than in Pollicipes, but Mg was higher than S only in the digestive gland and adductor muscle of Neolepas. Zinc was detected only in the digestive gland of Neolepas. Thus it appears that while Neolepas is in- gesting and assimilating some Mg from the hydrothermal environment, it is ingesting but not assimilating Zn because there were no significant amounts in the musculature and exoskeleton.
The source of the Zn found in the digestive gland must be from ingested material from the surrounding water, presumably inorganic particles and the food, because there are only traces in the immediate substratum. The food is probably in good part bacteria that may be clinging to and extracting free energy from suspended zinc sulfide and similar oxidizable particles (K. H. Nealson, personal communication). Bacteria utilizing H,S may also be involved (Corliss et al., 1979). It is notable that the filter feeding appendages and mouthparts of Neolepas are especially adapted to handle ex- tremely fine particles.
ACKNOWLEDGMENTS
Thanks are due to Drs. F. Grassle and R. Hessler for allowing me to work on this material. I am most grateful to Dr. R. Ballard for collecting the specimens of Neolepas; to Drs. J. Hawkins, P. Lonsdale and K. Nealson for discussions about hydrothermal environments: to R. La Borde (Analytical Facility, SIO) for advice on the chemical analyses; to Drs. F. Schram and R. Hessler for helpful criticisms of the first draft of the manuscript; and to Drs. R. Scheltema and R. Strathmann for general discussions on reproductive strategies in marine invertebrates. The photo (Fig. 1) of Neolepas was taken by Mr. Larry Ford (Photographic Laboratory, SIO), and the drawings were prepared by Ms. Nancy Freres. Thanks are also due the Rise Project Group, supported by National Science Foundation grants OCE 78-01664, 78-21082 and 79-00984, for bringing together the technology and expertise that made the collection of the speci- mens of Neolepas possible. Support from the National Science Foundation (DEB 78- 15052) for work on the systematics of cirripeds is gratefully acknowledged.
LITERATURE CITED
Achituv, Y., and H. Barnes, 1978. Some obser- Drushchits, V. V., and G. B. Zevina, 1969. New vations in Tetraclita aquamosa rufotincta Lower Cretaceous Cirripeds from the North- Pilsbry. Journal of Experimental Marine Bi- ern Caucasus. Paleontological Journal (2):73-
ology and Ecology 31:315—324.
Barnes, H., and M. Barnes, 1968. Egg numbers, metabolic efficiency of egg production and fe- cundity: Local and regional variations in a number of common cirripedes. Journal of Experimental Marine Biology and Ecology 2:135-153.
Broch, Hj., 1922. Studies on Pacific cirripeds, pa- pers from Dr. Th. Mortensen’s Pacific Expe- dition 1914-1916, No. X. Dansk naturhistorisk forening. Videnskabelige meddelelser 73:215— 358.
Corliss, J. B., J. Dymond, L. I. Grodon, J. M. Edmond, R. P. vonHerzen, R. D. Balland, K. Green, D. Williams, A. Bainbridge, K. Crand, and T. H. vanAndel, 1979. Submarine thermal springs on the Galapagos Rift. Science 203: 1074-1083.
Darwin, C., 1851. A Monograph of the Subclass Cirripedia, with figures of all species. The Le- padidae; or, pedunculated cirripeds. Ray So- ciety, London, v—xi, 1-400 pp., I-X pls.
85 (Moscow).
Ekman, S., 1953. Zoogeography of the Sea. Sidg- wich and Jackson, Ltd., London. 417 pp. Foster, B. A., 1978. The Marine Fauna of New Zealand: Barnacles (Cirripedia: Thoracica). Memoir 69, New Zealand Oceanographic In-
stitute, Wellington. 160 pp.
Francheteau, J., H. D. Needham, P. Choukroune, T. Juteau, M. Séguret, R. D. Ballard, P. J. Fox, W. Normark, A. Carramza, D. Cordoba, J. Guerrero, C. Rangin, H. Bougault, P. Cam- bon, and R. Hekinian, 1979. Massive deep-sea sulphide ore deposits discovered on the East Pacific Rise. Nature 277:523-528.
Gould, S. J., 1977. Ontogeny and Phylogeny. Har- vard University Press, Cambridge, Massachu- setts. 501 pp.
Gruvel, A., 1905. Monographie des Cirrhipedes ou Thecostracés. Masson et Cie., Paris, xii, 472 pp. 427 figs.
Hattin, D. C., 1977. Articulated lepadomorph cir- ripeds from the Upper Cretaceous of Kansas:
Family Stramentidae. Journal of Plaeontology 51:797-825.
Hoek, P. P. C., 1883. Report on the cirripeds col- lected by H.M.S. Challenger during the years 1873-1876. Report on the Scientific Results of the Voyage of H.M.S. Challenger, Zoology 8. 169 pp.
Madsen, F. J., and T. Wolff, 1965. Evidence of the occurrence of Ascothoracica (parasitic cir- ripeds) in the Upper Cretaceous. Saertryk af Meddelelser fra Dansk Geologisk Forening 15:557-558.
McLaughlin, P., and D. Henry, 1972. Comparative morphology of complemental males in four species of Balanus (Cirripedia Thoracica). Crustaceana 22: 13-30.
Nealson, K. H., and J. Ford. Surface enhancement of bacterial manganese oxidation: Implications for aquatic environments. Geomicrobiology (in press).
Newman, W. A., 1960. The paucity of intertidal barnacles in the tropical Western Pacific. Ve- liger 2:89-94.
Newman, W. A., 1974. Two new deep-sea Cirri- pedia (Ascothoracica and Acrothoracica) from the Atlantic. Journal of the Marine Biology Association of the United Kingdom 54:437- 456.
Newman, W. A., and A. Ross, 1971. Antarctic Cirripedia. Antarctic Research Series 14, American Geophysical Union. 257 pp.
Newman, W. A., V. A. Zullo, and H. H. Withers, 1969. Cirripedia, in Treatise on Invertebrate Paleontology (R. C. Moore, ed.), Part R, Ar- thropoda 4:R206—R295. Geological Society of America.
Normark, W. R., 1976. Delineation of the main extrusion zone of the East Pacific Rise at lat. 21°N. Geology 4:681-685.
Pilsbry, H. A., 1907. The barnacles (Cirripedia)
167
contained in the collections of the United States National Museum. Bulletin United States National Museum 60:122 pp., pls. 1-11.
Pilsbry, H. A., 1908. On the Classification of Scal- pelliform Barnacles. Proceedings of the Acad- emy of Natural Sciences 60:104-111.
Rokop, F. J., 1974. Reproductive patterns in the deep-sea benthos. Science 186:743-745. Schram, F. R., 1975. A Pennsylvanian lepado- morph barnacle from the Mazon Creek Area, Illinois. Journal of Paleontology 49:928—-930.
Sylvester-Bradley, P. C., 1961. Archaeocopida, in Treatise on Invertebrate Paleontology (R. C. Moore, ed.), Part Q, Arthropoda 3:Q100- Q103. Geological Society of America.
Vermeij, G. J., 1977. The Mesozoic marine revo- lution; evidence from snails, predators and grazers. Paleobiology 3:245—258.
Wills, L. J., 1963. Cyprilepas holmi, Wills, 1962, a pedunculate cirripede from the Upper Silu- rian of Oesel, Esthonia. Palaeontology 6:161— 165.
Withers, T. H., 1928. Catalogue of Fossil Cirripe- dia in the Department of Geology, I. Triassic and Jurassic. 154 pp. + 12 pls. British Mu- seum (Natural History), London.
Zevina, G. B., 1978a. 1. A new classification of the Scalpellidae (Cirripedia, Thoracica). Subfam- ilies Lithotryinae. Calanticinae, Pollicipinae, Scalpellinae, Brochiinae and Scalpellinae. Zoologichesky Zhurnal Akademiia Nauk SSSR 57(7):998-1007 (in Russian with English ab- stract).
Zevina, G. B., 1978). A new classification of the Scalpellidae (Cirripedia, Thoracica). 2. Sub- families Arcoscalpellinae and Meroscalpelli- nae. Zoologichesky Zhurnal Akademia Nauk SSSR _ 57(9):1343-1352 (in Russian with En- glish abstract). —
Scripps Institution of Oceanography A-002, La Jolla, California 92093 USA, and Natu- ral History Museum, Box 1390, San Diego, California 92112.
ADDENDUM:
Three interesting pieces of lore bearing on cirriped evolution came to my attention after this article went to press. The first, thanks to Dr. F. Schram (San Diego Natural History Museum), is a paper by M. A. Whyte (1976, A Carboniferous pedunculate barnacle. Proceedings of the Yorkshire Geological Society 4/, part 1, (1):1-12 + pls. 1 & 2), describing what appears to be the first Paleozoic scalpelliform lepadomorph. Whyte interprets it to be at the Eolepas/Archaeolepas level of scalpellid organization, including peduncular scales as well as a capitulum of 6 plates (the basic 5 plus the rostrum; Table | herein). This places the origin of the scalpelliforms some 50 million years earlier than previously recognized and then virtually contemporaneous with the more primitive lepadiform Praelepas (5 capitular plates and naked peduncle). However, with the more generalized Cyprilepadidae (one pair of capitular plates and naked peduncle) appearing in the Silurian, there is at least a 100-million-year span in which the lepadiforms can make their appearance before the scalpelliforms, as indeed they must have.
Actually there appears to have been even more time available than this (Silurian to Carboniferous) for the lepadiforms to appear, since the second piece of lore concerns an apparent pedunculate barnacle from the Burgess Shale being described by Desmond Collins and David Rudkin (Royal Ontario Museum). Dr. Collins, at the suggestion of Dr. A. J. Southward (Plymouth), kindly allowed me to see pictures of what I cannot fault as a pedunculate barnacle. Thus the origin of the cirripeds must have been in the earliest Paleozoic as inferred herein (Table 1).
The third piece of lore further heightens appreciation of the ancient roots of the cirripeds. Mr. Mark Grygier (Scripps Institution of Oceanography) has discovered that an ascothoracican, Dendrogaster sp. from the Ross Sea, has a generalized flagellated spermatozoan otherwise unknown to the Crustacea, and he has since received a personal communication from Dr. K. G. Wingstrand (Copenhagen) that another ascothoracican, Ulophysema from the North Atlantic, likewise has flagellated sperm. Thus the cirripeds are not only very old but they must have stemmed from a reproductively unspecialized stock.
A eS ial ea eae oon
igre Valente a ee; i ir aa hs fea ’ , i i) a ty ouah tn’
b aT Lage SN teat
eee a Ge ‘aes oi 06 T - 7 ‘an y pant be \ j Bs ee ta mt , wt pf Loe aes : iPey v aoe 7 : Fi ng ui) eo a
me ar at
ho Seem Seat un : ee eT ws ie ~~
ree Pol my, > or. = y ay See ee Se ied “ vA inet i AA: > _ et « OHM 4i') yee 41s amv ‘ ‘e at seo) pb eS) =) ~ e. 2
eel seve fl ig py are
vag wey : ' i See a. :
ee res = act ; om i cary a
| ‘ 4 = rs an
Sern ives ar : Ste CCM OE Oo) Gar) =— ree tt 5 bee OF
ea Pm mee Sy Gi: =a 4. ‘<= 4 y = a5 “si othe Ave Ei
= Se aie ie : vive
- Ts) i, Operites ioe “hl ay ft 7? nT ee Me ee Te cy Pe oh es en oc or i vee ae eit : - et | als Wie ? 4 7 a "| wh aa t 7 : = roe 1% ¥,' ed Tae wae 9 d : ’ fia & 'T hati var a ’ = 2, bt oe 4 2 ane ax fj a ; a “SS ts See- 7) 7 ' “we es =p Pe ents ; 7 ? 7 y — oe ie o ® 7 e , 7 i - ’ 7 if 7 i 7) = — 4 > - —_ A | 17 = 7 Wa meer ‘aay “Vos Nee _ <a = : yo v 7 = te + R= GO 7 on oa , » fireug Ty
i OA 6 4 Oe ein wi? ~ a W]e an 4 on “vo Bie ab=5 7 ae ae L iv, , ants 1s 3 Dens , 1 te ray 4: =. Je paneer a =i wo ATT AL wf prety Des Al Seoare res 2 vi or ab r lion i ve ir R= oy) cts =p! - ‘Wras pant hails io oa * 042 time |
eer met oleae
aaa vig bx
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 12 pp. 169-179 10 April 1980
Four species of Pterynotus and Favartia (Mollusca: Gastropoda: Muricidae) from the Philippine Islands
Anthony D’ Attilio and Hans Bertsch
Abstract. Four species of muricid gastropods from the Philippine Islands are discussed and fig- ured. Three of the species are described as new.
INTRODUCTION
During the past several years collectors and fishermen in the Philippines have obtained many new or otherwise interesting specimens of marine mollusks. Some of this valuable material has been given by collectors and dealers to museums in this country for study and identification, resulting in the publication of several new taxa (see Emerson & D’ Attilio, 1979).
Through the courtesy of several shell dealers cited below, we have recently ob- tained for the collection of the San Diego Natural History Museum specimens of 4 species of muricid gastropods. These were obtained mostly by native Philippine fish- ermen using tangle nets laid out overnight in depths of 150 metres and less. One of these species was recently described by Dr. Kosuge in a new Japanese journal devoted to malacology; the other 3 are new species we describe herein.
Muricidae Rafinesque, 1815 Muricinae Rafinesque, 1815 Pterynotus Swainson, 1833
Type species Murex pinnatus Swainson, 1822 (=Purpura alata R6éding, 1798) by subsequent designation, Swainson, 1833 (text to plate 122).
The genus Pterynotus encompasses Muricinae shells having 3 or more varical flanges or flanges developing into spines. Several subgenera have been proposed for this genus, especially by Jousseaume, 1880. These subgeneric taxa have been variously accepted or rejected or at times raised to full generic rank. The present species are referable to Pterynotus sensu stricto based on their alate trivaricate morphology and dentate labrum (as in the generic type species). A variable characteristic of the genus is the presence or absence of denticles on the columella. The new species described here as Pterynotus aparrii has columellar denticles, whereas Pterynotus miyokoae lacks denticles.
Pterynotus miyokoae Kosuge, 1979 (Figures la, b, c, d)
Original reference.—Pterynotus miyokoae Kosuge, 1979, pp. 1-2, plt. 1, figs. 1-7.
Supplementary description.—The shell of the largest specimen we examined Is 67 mm high, broadly fusiform, protoconch of 1% polished rounded whorls; spire of mod-
erate height, strongly convex and possessing 7 whorls; suture deeply impressed. The
170
Fic. 1. Pterynotus miyokoae Kosuge, 1979. a. Dorsal view of shell, 67-mm-long specimen; Clifford and Clifton Martin Collection. b. Apertural view of shell of specimen illustrated in Fig. la. c. Dorsal view, 36- mm-long specimen; Ben and Ruth Purdy Collection. d. Dorsal view, 65-mm-long specimen, collected at Russell Island in the Solomons; AMNH 196014.
body is of moderate size relative to spire; canal moderately long, terminally attenuated, and recurved with a sinuous narrow opening. Aperture is broadly ovate, the anal sulcus is bracketed by a denticle on either side; immediately below the small denticle at the sulcus the entire outer crenulate lip has a continuous series of strong elongate denticles
171
arranged singly posteriorly and in pairs anteriorly; closer to the apertural margin the major denticles have smaller swellings on either side which may become terminally bifurcate; the arcuate columella is simple.
Axial sculpture consists of 3 broad, wing-like varices which expand continuously from the lower portion of the canal to their termination at the suture. In addition the elongated varical wing is decidely recurved over the shoulder. The varices are aligned slightly oblique to the axis, and the flanges overlap on the spire with each new flange on the receding side of the earlier one; the margins of the varices terminate in short fine, spiny extensions varying slightly in length according to the strength of the spiral cords, but increasing in length so that the longest spine is near the preceding whorl. On the final and central varix there is a strong axial swelling which is the result of a strong depression between the varix and body and another lengthy depression on the forward side of the varical flange.
Two nearly equally-sized knobby costae are found intervarically on the shoulder and fading before the base of body whorl. Spiral sculpture consists of numerous pri- mary cords (about 26) extending from the suture to the lower portion of the canal; the interspaces between the primary cords contain secondary or lesser cords; all spiral sculpture is scabrously ornamented except that when the scales are abraded the thick- ened bases of the scales remain in the form of knobs. The fluted leading (ventral) sides of the varical wings are scabrously laminate heavily below, lightly above where the surface displays strong fluting.
The shell is a medium shade of rust or rust brown; with one slightly paler band at the shoulder, one at the base of the body, and a much weaker one is perceptible on the canal. In light-colored specimens the shell appears white with pale brown bands. There is a narrow whitish band at the suture, the aperture is off white. Some specimens differ in the intensity of the brown color which is chocolate brown in one specimen.
The operculum is typically unguiculate muricine with the nucleus at the base and concentric ridges radiating from the nucleus.
Type locality. —Off Mactan Island, Cebu, Philippines, in 200 m.
Material examined.—1) One shell, 67 mm long; collected in the Philippine Islands, March 1979, from fishermen’s nets, depth unknown; in the collection of Clifford and Clifton Martin. :
2) Two specimens, 62 mm and 36 mm; dredged at Vaval, in the Philippine Islands, depth unknown. These specimens are in the collection of Ben and Ruth Purdy.
3) Two shells, 65 mm (AMNH collection 196014) and 53 mm (Robert and Dorothy Janowsky collection) long; collected at Russell Island in the Solomons (slightly south- east of 9° S; 159° E), January 1977, dredged from 600 feet (off a fine sand bottom with coral rubble). These specimens constitute a southeastward range extension for Prery- notus miyokoae of ~4000 km from the Philippines.
Discussion.—As suggested by Kosuge, this species is most closely related to Pter- ynotus loebbeckei (Kobelt in Lébbecke and Kobelt, 1879), a species previously known from the area of Cebu and Bohol Islands in the Philippines as well as from the type locality in southeastern Japan. Through the courtesy of R. and D. Janowsky, we have examined specimens of P. loebbeckei (which establish a westward range extenstion of more than 8000 km) collected at Reunion Island in the Indian Ocean.
Pterynotus loebbeckei lacks the strongly sculptured characters of P. miyokoae, in that the axial costae are weak and form no prominent feature of the shell; the heavy ridge forms a conspicuous feature of the varical base in P. miyokoae but is lacking in P. loebbeckei; the varical margin is only weakly recurved; the strongly recurved por- tion of the varical flange over the shoulder on P. miyokoae but wanting in P. loeb- beckei, being reduced in a descending manner towards the previous whorl. The colu- mella of P. miyokoae in the 5 examples we examined is smooth and does not possess the characteristic strong denticles on the upper and lower portion which occur in P. loebbeckei; the outer (labrum) apertural denticles in P. loebbeckei are of simple form showing no other sculptural elaboration as in the new species. In contrast to the banded brown over whitish coloration of the new species, P. loebbeckei has an apricot orange
2
or orange pink coloration within the outer portions of the aperture, and on the columella callous as well as over the remaining shell.
Pterynotus aparrii D’ Attilio & Bertsch, sp. nov. (Figures 2a, b, c, d)
Description.—Shell reaches approximately 35 mm high; narrowly fusiform, pro- toconch not preserved; spire relatively low of fine moderately convex whorls; suture weakly impressed; body whorl weakly convex and moderate in size; canal long, ter- minally tube-like and strongly recurved and narrowly open. Aperture is of a tear-drop shape, pointed anteriorly; anal sulcus u-shaped with a large knobby denticle on the outer side; the outer lip is wavy with crenulations reflecting the spiral sculpture and there are 5 short elongate denticles within the lower portion of the apertural margin; between these denticles and the large posterior one delimiting the anal sulcus there is a gap which has only one small denticle; the inner lip is adherent above, erect below and possesses 3 denticles on the lower half of the columella. The canal possesses the extension of a varical flange on its right side; a prominent recurved canal from a previous whorl is on its left side.
Axial sculpture consists of 3 blade-like varices which cross the shoulder strongly, diagonal to axis; the last and intermediate blade only is well developed; the varical blades are undulating and the margins have large lobe-like extensions at the shoulder, a secondary one at the base of body whorl and a lesser one on the canal; a single weak costa is found intervarically.
The spiral sculpture consists of numerous cords of minor or major character with the stronger cords extending the varical blade into a spiny-edged lobe; there are 3 major cords at the shoulder lobe, 2 to 3 major cords at the base of the body whorl and 2 on the canal; finer cords occur between the major cords to form a continuous varical blade from above the recurved portion of the canal to a termination of the blade against the preceding whorl; the entire surface of the intervarical area and the dorsal side of the varical blades are crossed by close set raised growth striae which are in addition scabrous when not abraded. The leading side of the varical blades are scabrously laminate below on the thickened varix, and less so on the fluted area of the blades as they project above the thickened varix.
Color of shell is pale orange; aperture is a deeper orange especially rich in the area of the denticles.
Operculum not known.
Material examined.—1) Holotype, San Diego Natural History Museum, Depart- ment of Marine Invertebrates, Type Series: SDNHM T.S. 518. Shell is 35 mm long; collected at Punta Engano, Cebu Island, in the Bohol Straits, Philippine Islands, 1978, from fishermen’s nets in approximately 75-100 metres of water.
2) Two specimens, 32 mm and 27 mm long; collected at Punta Engano, Cebu, 1978, fishermen’s nets. These specimens are in the collection of Ben and Ruth Purdy.
3) One specimen, 37 mm long; collected at Panglao, Bohol, Philippine Islands. This shell has a golden yellow coloration, and is in the collection of Gene Everson.
Type locality.—Punta Engano, Cebu Island, Bohol Straits, Philippine Islands (ap- proximately 10° 20’ N; 124° E).
Etymology.—The patronym honors a knowledgeable shell fisherman, Mr. Rudol- pho O. Aparri of Cebu City, Philippine Islands (the -ii suffix results from adding the genitive singular case-ending to the entire surname).
Discussion.—This new species has a smaller shell than Pterynotus loebbeckei which it resembles superficially because of its color. It also resembles both in color and in size Pterynotus bibbeyi (Radwin and D’ Attilio, 1976), known mostly from south- eastern Japan.
The new species differs in having 3 varices, whereas in P. bibbeyi all specimens examined have 4 varices. Pterynotus aparrii also resembles Pterynotus laqueatus (Sowerby, 1841) which has a similar size and somewhat similar coloration. However,
173
Fic. 2. Pterynotus aparrii D’ Attilio & Bertsch, sp. nov. a. Dorsal view, holotype specimen, SDNHM T.S. 518 (shell is 35 mm long). b. Apertural view, holotype specimen, SDNHM T.S. 518. c. Dorsal view, 32-mm- long specimen; Ben and Ruth Purdy Collection. d. Dorsal view, 27-mm-long specimen; Ben and Ruth Purdy Collection.
P. laqueatus has not yet been discovered elsewhere than at Guam in depths accessible to scuba diving, in about 25 to 30 metres. Pterynotus laqueatus differs by its regular subcircular aperture, proportionately higher spire, coarser spiral sculpture, a strong intervarical costa, an additional costa at base of receding side of the varix, and its color which is variably shaded pink, pink-violet and pale orange.
174
Muricidae Rafinesque, 1815 Muricopsinae Radwin & D’ Attilio, 1971 Favartia Jousseaume, 1880
Type species, Murex breviculus Sowerby, 1834, by original designation. Recent workers have treated the species referable to Favartia and Murexiella Clench and Perez Farfante, 1945, at differing generic-subgeneric levels. Radwin and D’ Attilio (1976:144-161) recognized these genus-group taxa as full genera. Ponder (1972) vir- tually synonymized the 2 taxa, giving only a token subgeneric status to Murexiella, because the ‘‘shell features are not consistently different in species ascribed to both groups.
It is true that the species of Favartia/Murexiella show a range of variation for a number of characteristics, which appears diverse and inconsistent. A clear example of the range of shell morphology can be seen by comparing sculpture, spine length, and varical flange development of various species of Favartia: F. humilis (Broderip, 1833), F. macgintyi (M. Smith, 1938), F. salmonea (Melvill and Standen, 1899), F. confusa (Brazier, 1877), F. cellulosa (Conrad, 1846), and F. brevicula (Sowerby, 1834).
We agree with Ponder that justification does not exist for both Favartia and Mu- rexiella to be recognized at the generic rank. We afford Murexiella subgeneric rec- ognition and restrict to this taxon, species that have the long spines connected by varical webbing that is characteristic of Favartia (Murexiella) hidalgoi (Crosse, 1869), the type species, including also: F. (M.) bojadorensis (Locard, 1897?), F. (M.) radwini (Emerson and D’ Attilio, 1970), F. (M.) diomedaea (Dall, 1908), F. (M.) mactanensis (Emerson and D’ Attilio, 1979), and F. (M.) martini (Shikama, 1977).
Regardless of the different generic interpretations, the 2 new species described here are referable to Favartia (sensu stricto).
Favartia pelepili D’ Attilio & Bertsch, sp. nov. (Figures 3a, b, c)
Description.—This species has a shell attaining over 30 mm in height; is biconically fusiform, an indeterminate protoconch, a high spire of 5 weakly shouldered whorls, suture weakly defined: body moderately broad; canal broad above, below tapering tubelike and terminally strongly recurved, very narrowly opened, and bearing 3 pre- vious terminal portions of the canals on its left side; aperture ovate moderately small with the margin strongly erect; the outer lip undulated into 5 troughs or grooves ex- tending within for a short distance; no appreciable anal sulcus discernible.
Axial sculpture consists of 5 varices raised above into spiny extensions; the varices are aligned moderately diagonal relative to the axis of the shell, and over the shoulder the notable varical margin arches very strongly to the following varix, in part obscuring the suture; very fine growth striae are found intervarically.
Spiral sculpture consists of 5 rounded cords, the uppermost one at the shoulder, the interspaces between the cords diminish progressively to the fifth cord at base of body. The cords develop into recurved spines above (at apex) the varix, the shoulder one is longest and less recurved than the following 3, the last spine (Sth) is much less recurved and is pointed in the growing direction. The spine on the canal is forward projecting and otherwise similar to the lowest spine on the body. Terminally these spines spread out into 2 or 3 folded lobes. Spinelets are distributed one each between the spines on the body and the canal spine. Two or 3 overlapping spinelets constitute the ornamentation on the varix across the shoulder. The spines are weakly opened or fold inwardly to touch centrally. On their leading side a 2nd smaller set of similar spines is nested between the lower portion of the major spines; below these secondary spines there are yet smaller similar spines. Between the last spines and the varical margin there are a few weak scabrous lamellae. The structure of secondary spines forms in effect a low webbing between the spines.
The shell is a light umber brown and a paler lighter umber suffuses the aperture.
The holotype is 33 mm long. The paratype is smaller (18 mm in length) and is
yes)
Fic. 3. Favartia pelepili D’ Attilio & Bertsch, sp. nov. a. Dorsal view, holotype specimen, SDNHM T.S. 519 (shell is 31 mm long). b. Apertural view, holotype specimen, SDNHM T.S. 519. c. Dorsal view, paratype specimen, SDNHM T.S. 520 (shell is 18 mm long). Favartia judithae D’ Attilio & Bertsch, sp. nov. d. Dorsal view, 20-mm-long shell; Judith Bertsch Collection.
distinguished from the holotype by the comparatively extreme length of the shoulder spines which are not bent and project diagonally upward as high as the spire. Color of paratype similar to holotype.
Material examined.—Two specimens; Holotype, SDNHM T.S. 519; shell is 33 mm long. Paratype, SDNHM T.S. 520; shell is 18 mm long. Both specimens collected in the Bohol Straits, between Bohol and Cebu Islands, Philippine Islands, early in 1979, by fishermen’s nets in approximately 75 to 100 metres of water.
176
Fic. 4. Favartia judithae D Attilio & Bertsch, sp. nov. a. Dorsal view, holotype specimen, SDNHM T.S. 521 (shell is 25 mm long). b. Apertural view, holotype specimen, SDNHM T.S. 521. c. Dorsal view, paratype specimen, SDNHM T.S. 522 (shell is 19 mm long). d. Apertural view, paratype specimen, SDNHM T-.S.
S22:
Type locality.—Bohol Straits, Philippine Islands (approximately 10° 20’ N; 124° E). Etymology.—The species name means Pele’s hair (a combination of Pele—Hawai- ian volcano goddess, and pili—Latin plural, hairs; used as a noun in apposition; the genitive ending has been omitted from Pele for the sake of euphony), a term in vul- canology that indicates volcanic glass spun out into hairlike form. The shell with its long spines resembles a small piece of lava with wind-blown ‘‘hair’’ streaming behind.
TAT
Discussion.—This species differs from other Indo-Pacific species of Favartia by its larger size and longer spines on the varices. Favartia salmonea (Melvill and Stan- den, 1899) represents the opposite end of this type of shell development with varices having poorly developed scale-like spines; it also has a richly variable coloration from pink to orange or red. An intermediately related form is Favartia balteata (Sowerby, 1841), easily recognized by its flesh colored shell, rosy aperture, and short, burnt- brown, foliose scaley spines. Two other related species are Favartia voorwindei Pon- der, 1972 and Favartia striasquamosa Ponder, 1972, which differ in having uncolored smaller shells of ~10 mm and relatively lower spined varices numbering 6 to 7.
Favartia judithae D Attilio & Bertsch, sp. nov. (Figures 3d, and 4a, b, c, d)
Description.—This species reaches a length of ~25 mm. The shell is broadly bi- conically fusiform, the protoconch (Fig. 4c—d) has 2/2 rounded whorls, the spire is mod- erately high and consists of 5 convex whorls; the suture is weakly defined; the body whorl is broad and convex; the ovate aperture is moderate in size; the margin of the in- ner lip is adherent above and weakly erect below, the outer lip has an undulate margin that is a reflection of the external spiral sculpture; no ana! sulcus discernible; the barely open canal is broad above with the tube-like recurving distal portion bent at a right angle, this character is best seen when this portion of the canal is preserved; in the holo- type the canal ends shortly after starting to recurve. The terminal portions of 4 former canals are preserved on the siphonal fasciole.
Axial sculpture consists of 7 varices, the varices are broad with relatively narrow intervarical spaces; the varices are continuous over the shoulder from whorl to whorl and aligned diagonally to axis of the shell; the varical margins arch to the preceding whorl thereby obscuring the suture.
Spiral sculpture consists of 5 rounded cords situated from shoulder to base of body and progressively diminishing in strength in that direction; transverse striae are very fine. After crossing the intervarical spaces the cords terminate as spines above the crest of the varix. The shoulder spine is strongest but weakly recurved relative to the 2nd and 3rd which are more strongly recurved and in addition are twisted poste- riorly; the 4th and Sth spines diminish in size and degree of recurving. All spines are open with their forward directed margins strongly undulate. Three progressively short- er similar spines are nestled below and within each main spine; the remaining varical area between the spines and the margin is ornamented with a few rows of scaly laminae. There is a strong spine on the canal preceding its recurved distal portion, additional single spinelets occur between the major spines, and 3 or 4 spinelets are situated between the spine on the canal and that on the body whorl. The varix above the shoulder has 4 or 5 marginally scabrous spinelets.
Shell color is a relatively rich flesh pink; the aperture ranges from a deeper pink to light red. ;
Material examined.—Three specimens. Holotype, SDNHM T.S. 521; shell is 25 mm in length. Paratype, SDNHM T.S. 522; shell is 19 mm in length. One specimen, shell length 20 mm, in the collection of Judith Bertsch. All 3 specimens were collected by tangle nets (in about 75 to 100 metres depth) off the north end of Mactan Island, Bohol Straits, Philippine Islands.
Type locality. —Bohol Straits, between Cebu and Bohol Islands, Philippine Islands (approximately 10° 20’ N; 124° E).
Etymology.—This species is named for Judith Bertsch, wife, fellow diver, and field assistant.
Discussion.—This species has a compact shell, richly scabrous in sculpture, and of similar morphology to Favartia pelepili. It differs from that species in the number of varices (7 as against 5 for F. pelepili), its smaller size and the reddish coloration in place of light brown. In contrast to the present taxon, most species of Favartia have smaller shells (except F. breviculus) and are commonly colored some shade of white
178
or grey white. It is distinguishable from other Indo-Pacific species for the same reasons specified in the discussion of F. pelepili.
In both Favartia pelepili and F. judithae, the leading (adapertural or growing) side of the spines is exceedingly complex and bristly, bearing many smaller spines jammed up against each other. The receding (abapertural) edge, by comparison, is almost smooth. This extreme development of spines upon spines, and the great length of the major spines that recurve almost to 180°, are more characteristic of these two new species than other Favartia species in which these traits are less pronounced.
ACKNOWLEDGMENTS
We are grateful to the following people who allowed us to examine specimens in their collections (those marked with an asterisk donated specimens to the San Diego Natural History Museum Marine Invertebrate collection): Judith Bertsch, L. J. Bibbey (*), Gene Everson, Robert and Dorothy Janowsky, Clifford and Clifton Martin (*), and Ben and Ruth Purdy (*). We are also grateful to Dr. William K. Emerson, American Museum of Natural History, Dr. Emily H. Vokes, Tulane University, and Dr. Reid Moran, San Diego Natural History Museum, for comments on various portions of this manuscript.
LITERATURE CITED
Brazier, John. 1877. List of marine shells with Locard, Arnould. 1897. Expedition scientifique de
descriptions of the new species collected dur- ing the “‘Chevert’’ expedition. Proceedings of the Linnean Society of New South Wales 1:169-181. (not seen)
Broderip, William John, and George Brettingham Sowerby. 1833. The characters of new species of Mollusca and Conchifera, collected by Mr. Cuming. Proceedings of the Zoological Society of London (1832) 2:173-179. (14 Jan- uary 1833)
Clench, William J., and I. Perez Farfante. 1945. The genus Murex in the western Atlantic. Johnsonia 17:1—56; 28 plts. (29 May 1945)
Conrad, Timothy Abbott. 1846. Descriptions of new species of fossil and recent shells and cor- als. Proceedings of the Academy of Natural Sciences of Philadelphia 3(1):19-27; 1 plt.
Crosse, Joseph Charles Hippolyte. 1869. Diag- noses molluscorum novorum. Journal de Con- chyliologie 17(4):408—410. (1 October 1869)
Dall, William Healey. 1908. The Mollusca and Brachiopoda. Bulletin of the Museum of Com- parative Zoology, Harvard 43(6):205—487; 22 plts. (October 1908)
Emerson, William Keith, and Anthony D’ Attilio. 1970. Three new species of muricacean gas- tropods from the eastern Pacific. The Veliger 12(3):270-274; plts. 39-40: 4 text figs. (1 Jan- uary 1970)
Emerson, William Keith, and Anthony D? Attilio. 1979. Six new living species of muricacean gastropods. The Nautilus 93(1):1—10; 21 text figs. (10 January 1979)
Jousseaume, Felix Pierre. 1880. Division metho- dique de la famille des Purpurides. Le Natu- raliste 2(42):335—336. (15 December 1880)
Kosuge, Sadao. 1979. Descriptions of two new species of the family Muricidae (Gastropoda, Mollusca). Bulletin of the Institute of Mal- acology Tokyo 1(1):1—2; I plt. (30 May 1979)
Travailleur et du Talisman. Paris, vol. 1, 515 pp.; 22 plts.
Loébbecke, Th., and Wilhelm Kobelt. 1879. Diag- nosen neuer Murices. Jahrbuch der Deutschen Malakozoologischen Gesellschaft 6(1):78-79. (January 1879)
Melvill, James Cosmo, and Robert Standen. 1899. Report on the marine Mollusca obtained during the first expedition of Prof. A. C. Had- don to the Torres Straits in 1888-1889. Journal of the Linnean Society of London 27: 150-206; plts. 1-2. (not seen)
Ponder, Winston F. 1972. Notes on some Austra- lian genera and species of the family Muricidae (Neogastropoda). Journal of the Malacological Society of Australia 2(3):215—248; 23 plts.; 4 text figs. (24 March 1972)
Radwin, George Edward, and Anthony D’Attilio. 1971. Muricacean supraspecific taxonomy based on the shell and the radula. Abstracts and Proceedings of the Fourth Annual Meeting of the Western Society of Malacologists, The Echo 4:55—67; 23 text figs. (27 December 1971)
Radwin, George Edward, and Anthony D’ Attilio. 1976. Murex shells of the world: an illustrated guide to the Muricidae. Stanford University Press, Stanford, California. 285 pp., 32 plts.; 192 text figs. (16 December 1976)
Rafinesque, Constantine Samuel. 1815. Analyse de la nature on tableau du univers et des corps organises. Barravecebia, Palermo. (not seen)
Roding, Peter Friedrich. 1798. Museum Bolten- ianum sive catalogus comeliorum e tribus reg- nis naturae. J. C. Trappit, Hamburg. viii & 199 pp.
Shikama, Tokio. 1977. Descriptions of new and noteworthy Gastropoda from western Pacific and Indian Oceans. Science Reports of the Yokohama National University, Sec. II, No. 24:9-23; 5 plts.; 1 text fig. (November 1977)
Smith, Maxwell. 1938. Further notes upon Ter- tiary and Recent mollusks from Florida, with descriptions of new species. The Nautilus 51(3):88-91. (January 1938)
Sowerby, George Brettingham II. 1834. The con- chological illustrations, parts 62 and 63; 2 plts. (30 June 1834)
Sowerby, George Brettingham II. 1841. The con- chological illustrations, part 18 to 192; 6 plts. (Plates 187-190, 1 January 1841; plts. 191-192, February 1841)
179
Swainson, William. 1820-1833. The zoological il- lustrations. Baldwin, Cradock and Joy, Lon- don.
Swainson, William. 1822. A catalogue of the... shells which formed the collection of Mrs.
Bligh, with an appendix containing ... de- scriptions of many new species. London 58 pp.; plts. 1-2.
Department of Marine Invertebrates, San Diego Natural History Museum, Balboa Park, P.O. Box 1390, San Diego, California 92112 USA.
. ater itt 7 a .
“Tt
en te ys oe as — . ¥ a : Di te nies Ji yf Lili iy a ML hablo) A ee : : ili :
- : aig" <1 ae i Th ms a] al js AL AT} dee stad i on i 4 ; Py ay i a a i) rab pu . : ; Cl ey AOR Dea Pista : | wiry
, PAPAL Me PY Ss ih SU ai payire si) MAW! peng nih, iam oe on 4 i, | ; qa! : ¥, | Site; ly ena AY ire fj win wa 3 Ue iss
Ni % ih a Oi j ie bilverts i ‘74 “e :
; 7 I | Mi} Pee ar HM
fi ' } of ‘ 1 J ' ‘ a ~ S - - 1 j ‘ ’ i es : ’ 7 ( ' tz 7 ~— ~~ J ) i | ty a i <@ ¥ s i ne _ 7 oT or —
TRANSACTIONS
OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 13 pp. 181-211 30 June 1980
A revision of the species of Cafius Curtis from the west coast of North America with notes of the east coast species (Coleoptera: Staphylinidae)
R.E. Orth and Ian Moore
Abstract. Ten west coast species of Cafius are described in detail. Lectotypes have been selected and are recorded for 8 of them. Cafius bistriatus (Erichson) and Cafius caribeanus Bierig are reported for the first time from western North America. Five east coast species are discussed. Cafius sericeus Holme does not occur in North America. The species previously reported under that name is Cafius aguayoi Bierig. Separate keys are presented for the west coast and east coast species. Drawings of the dorsal aspect and of the aedeagus of each species are given.
INTRODUCTION
Members of genus Cafius are generally restricted to seashores and the margins of rivers near the sea throughout the world. These insects are highly mobile, both on sandy beaches and in the air. ;
This study was undertaken because of the difficulty of distinguishing members of 2 Pacific coast species, Cafius sulcicollis (LeConte) and Cafius decipiens (LeConte), from the existing literature. Examination of type specimens has resolved that problem and indicated the presence of 2 species not previously reported from the west coast of North America.
According to Blackwelder (1952), the name Cafius was validated by Curtis in 1829 by ‘‘virtual monotypy.’’ He said, ‘‘Curtis listed three species in 1829, but two of these are nomina nuda.’’ The type species is Cafius xantholoma (Gravenhorst), a European species.
A few species of genus Philonthus were originally described in Cafius because of their seashore habitat, including one, Philonthus nudus (Sharp), from the west coast of North America. Members of Philonthus do not have the pronotal side margin deflexed, so that in Philonthus the large setigerous central puncture is on the marginal carina or removed from it by no more than the width of the puncture. In Cafius, and most other genera of the subfamily Staphylininae, the pronotal side margin is strongly deflexed in front so that the large central setigerous puncture is removed from the lateral carina by a least 3 x the width of the puncture. This is an excellent character for separating members of Cafius from those of Philonthus. Philonthus nudus (Sharp) (= Philonthus johnsoni [Fali]) was treated as a Cafius by Sharp (1874), Fall (1916) and Koch (1936); but it is obviously a Philonthus, as pointed out by Moore (1965). Another character useful in separating members of the 2 genera is dilation of the anterior tarsus. In Cafius, the anterior tarsus of both sexes is usually broadly dilated. In Philonthus nudus, the anterior tarsus is dilated very feebly in males and not at all in females.
Fifty-three species of Cafius are presently recognized. The majority of these are from temperate regions, although several species are widespread in the tropics. Four species are known from Europe, 4 from Japan, 12 from Australia, Tasmania and New Zealand, and
182
13 from North America. Of the North American species, 10 are found on the Pacific coast, 5 on the east coast and the West Indies, 2 of the species being common to both regions.
The first 2 species to be described from Pacific North America, Cafius femoralis and Cafius canescens, described by Maklin (1852), were from Alaska. In 1863, LeConte described Cafius opacus, Cafius dubius (a synonym of C. opacus), Cafius lithocharinus, Cafius decipiens, and Cafius sulcicollis all from San Diego, California. Horn revised the North American species in 1884 and added 2 new species from California, Cafius seminitens and Cafius luteipennis. Fall (1916) described an insect from Washington as Cafius johnsoni. This species was treated as a subspecies of Cafius nudus (Sharp) from Japan by Koch (1936), and later removed to Philonthus by Moore (1965). Koch (1936) revised the world species of Cafius, but described no new North American species. Hatch (1957) treated the 5 Cafius species known from the Pacific Northwest and included good illustrations of them. The present study adds 2 species to the list of Pacific North American species.
Cafius has been divided into a number of subgenera. The North American species have been assigned to several of these subgenera. We feel that the subgenera which have been applied are poorly conceived and do not reflect phylogeny. Consequently we have not used the subgeneric category in this study.
Descriptions of larvae and pupae and notes on ecology have been provided for 4 of these species by James et al. (1971) and for 1 by Moore (1975). They observed that both larvae and adults are predaceous. Orth et al. (1978) found noxious beach flies to be less abundant when large numbers of staphylinids, mostly species of Cafius, were present in wrack where these flies were breeding. When staphylinids were scarce or absent, fly larvae were present in great numbers in the wrack and adult flies swarmed on the beach. They speculated that, under normal conditions, beach flies were under good natural biological control by wrack-inhabitating staphylinids.
METHODS
All measurements refer to greatest width or length of a given part. Length of the tem- pora is from the bottom of the eye to a line tangential to the base of the head. Suture of the elytra is measured from the posterior tip of the scutellum to a line tangential to the apices of the elytra.
Male genitalia, particularly the shape and relative lengths of the aedeagus and paramere, offer good characters for separating members of some of the species. When viewed from the side, the paramere usually touches or closely approaches the aedeagus at 2 points besides its basal attachment to the aedeagus, one near its middle and the other near its apex. These are raised areas on the aedeagus; so we have called them the middle tumescence and the apical tumescence. The relative distance of these 2 points from the basal attachment, from one another, and from the apex of the paramere are useful characters in distinguishing some species.
We have examined type material in the LeConte and Horn collections in the Museum of Comparative Zoology (MCZ), Harvard University. These collections consist of series of various numbers of specimens described by the above persons, as well as specimens of Cafius canescens and Cafius femoralis from Maklin’s type series.
Because there is some question as to which specimens constitute the original type series of some of these species, and to justify our choice of lectotypes, we have listed in full the data present on all specimens from both the LeConte and Horn collections.
In a letter written by John L. LeConte to Alexander Agassiz in 1875 and later published in the Coleopterist’s Bulletin (LeConte, 1961), LeConte stated, in reference to his collection, ‘‘It has been enriched by the extreme liberality and courtesy of many distin- guished European entomologists who have sent me even the second specimens of many North American species, which were otherwise unobtainable at that time. I have thus nearly a complete series of the species described from the West Coast by Eschscholtz,
183
Mannerheim and Maklin.’’ This information was taken into consideration in selecting lec- totypes for Maklin’s species from the LeConte collection.
A single specimen (usually the first in each series) in the LeConte and the Horn collec- tion bears a red label reading ‘‘Type’’ and a number. These were apparently affixed by N. Banks, but never published, so they are not lectotypes. In most cases, we have selected specimens which we felt were more suitable as lectotypes than those specimens with the red ‘‘Type’’ labels.
The following abbreviations of names of repositories have been used: (CAS)-California Academy of Sciences, San Francisco; (ERIC)-Entomological Research Institute of Canada, Ottawa; (FMNH)-Field Museum of Natural History, Chicago; (MCZ)-Museum of Comparative Zoology, Harvard; (UCR)-University of California, Riverside; (USNM)-United States National Museum, Washington, D.C.
KEY FOR IDENTIFICATION OF CAFIUS OF WESTERN NORTH AMERICA
A. Pubescence of each abdominal tergite arranged on each side in the form of a cowlick so that outer hairs lie diagonal to lateral margin. B. Two terminal sternites contrastingly more densely pubescent than preceding
RRETIN TES We aera uk oi kc ee Sn ca acess 1. C. seminitens Horn BB. Two terminal sternites not more densely pubescent than preceding RICRIMMC Stee trea ea Ee ee a ca my eian Ven mera d one ir < 2. C. canescens (Maklin)
AA. Pubescence of abdominal tergites entirely longitudinal.
C. Tenth antennomere longer than wide.
DD: Suture of elytra. shorter than pronotum ................ 3. C. opacus (LeConte) DD. Suture of elytra not shorter than pronotum ............ 4. C. femoralis (Maklin) CC. Tenth antennomere not longer than wide.
Ev eunctunes ofmuncdersuniace of head panthycoalescemt > js 449.- see ieee ee
EE. Punctures of undersurface of head not coalescent.
eae Ely tray bileitllouitt pire ores to eys eee tees abe sacs ons oe hous ue ye 6. C. luteipennis Horn FF. Elytra reddish-brown to piceus. Ge HeadinedGish=brOWMy. 2 eine. ac tris sari mols oMivteae ae baa 7. C. decipiens (LeConte) GG. Head black. H. Disc of pronotum strongly reticulate, dull............ 8. C. sulcicollis (LeConte) HH. Disc of pronotum feebly or not reticulate, shining. Io" Gulia strongly reticulate and eranulate” «.. 3.205 0. 9. C. bistriatus (Erichson) [idee Glew nchiMe nw WANN CS ine ane te apt ecient aciey oe acs 10. C. caribeanus Bierig
1. Cafius seminitens Horn Figs. 1A, 5A, 6A-C.
Cafius seminitens Horn, 1884, Trans. Amer. Ent. Soc. 11:235; Koch, 1936, Publ. Mus. Ent. Pietro Rossi, 1:183; Dvorak, 1957, Ent. News, 68:15 Fig. 1-2 (o"); Hatch, 1957, Univ. Wash. Publ. Biol. 16:211; Moore, 1965, Coleopt. Bull. 19:98 Fig. 7 (pt.); James, Moore and Legner, 1971, Trans. San Diego Soc. Nat. Hist. 16:282 (larva), 283 Fig. 2 (larva), 285 (larva), 286 Fig. 6 (pupa); Moore, 1975, Pan-Pac. Ent. 51: 140 (larva); Orth, Moore and Fisher, 1978, Wasmann Jour. Biol. 35:175 Fig. 5 (toto), 181, 182, 186 (ecology).
Description of lectotype.— 7
This male from the Horn collection in MCZ is labeled as follows: ‘‘Cal’’, ‘Horn coll/H2259’’, ‘‘seminitens/ [2] Calif.’ and ‘‘Lectotype/Cafius seminitens/Horn desig. ’78/ R.E. Orth, I. Moore.”’
Type locality. —‘‘California sea coast.’
The lectotype is the only specimen in the Horn collection. The following specimens
184
are in the LeConte collection: 1 female with a gold disc (California), a red label reading ‘“‘Type 7328” and white labels reading ‘‘P. seminitens Hn.”’ and ‘‘LeConte collection’’; a male with a gold disc, a ‘‘c’’’ symbol and ‘‘LeConte collection’; a specimen with a ‘‘o"”’ symbol, ‘‘Cal.’’ and ‘‘LeConte collection’’ labels; and 1 with “‘o’”’, “‘Cala.”’ and “‘T eConte collection”’ labels.
Length.—9.1 mm.
Color.—Largely dark brown, with head piceus and lower edge of elytral epipleura and humerus infuscate to yellow.
Head. —Quadrate, wider than long, slightly wider than pronotum, widest near middle of tempora which are noticeably bulbous; eye slightly more than half as long as tempora; disc of head with a short central longitudinal impression, with 6 to 8 large widely spaced punctures on each side of midline and several more closely placed punctures behind eye; surface with very faint strigulose ground sculpture in impressions, otherwise polished; undersurface almost impunctate, with distinct strigulose ground sculpture; gula densely reticulate; antenna hardly longer than head; 10th segment wider than long.
Pronotum.—Wider than long, widest near apical angles; front margin nearly straight, apical angles narrowly rounded, sides gently arcuate into broadly rounded basal angles and arcuate base; disc with a shallow central longitudinal impression and a series of irregularly spaced punctures on each side of midline, with a few scattered punctures at sides; surface without ground sculpture except very faintly in the 2 rows of discal punctures.
Elytra. —With suture somewhat shorter than length of pronotum; each elytron slight- ly narrower than sutural length; surface very densely and uniformly punctured throughout.
Abdomen.—With acrocostal sutures of basal tergites wavy, with a central wide shallow blunt posteriorly directed cusp; more sparsely but as coarsely punctured as elytra, reticulate between punctures; pubescence coarse, silver colored, diagonally arranged near midline and at sides, the latter somewhat in the manner of a cowlick. First 5 visible tergites with a large impressed puncture centrally on each side of midline. Sternites 5 and 6 almost twice as densely punctured and pubescent as preceding sternites. Apical margin of 6th sternite with a triangular emargination about as deep as wide, without a membranous margin. In ventral view, aedeagus quite blunt at its apex as in Cafius decipiens males; but paramere much shorter relative to the aedeagus, than that of C. decipiens males and has more pegs on its inner face.
Male characters. —First 4 segments of the anterior tarsus broadly dilated. Head sometimes proportionately much wider than in female. Apical margin of 6th sternite with a triangular emargination.
Female characters.—Anterior tarsus almost as broadly dilated as in male. Head uniformly small. Apical margin of 6th sternite entire.
Variation. —Head and pronotum discs are, in most adults, more shiny than in those of Cafius canescens. The 2 rows of longitudinal punctures on the pronotal disc are not consistent. One specimen which we have seen has only a single puncture on each side near the apical margin. Most specimens have 6 to 8 punctures on each side; one has as many as 13; the rows always seem to be interrupted in the middle. In some specimens the pale color of the elytral humerus extends along the basal margin and also includes part of the scutellum.
Notes. —Members of this species closely resemble those of Cafius canescens but can be distinguished from the latter by their silvery pubescent, short antennae, wavy acrocostal suture and, particularly their densely pubescent Sth and 6th sternites.
The larva and pupa were described and notes on ecology were provided by James et al. (1971).
We have examined 870 specimens.
Distribution.—This species is known from British Columbia to Rosario, Baja California del Norte, Mexico, and undoubtedly extends farther south along the unex- plored coast of Baja California, probably at least as far as Punta Eugenia, Baja Califor- nia Sur. According to Orth et al. (1978), it was abundant at Refugio State Beach, Santa
185
Barbara County, California, in the spring and summer and was present there in most other months, but only rarely encountered during midwinter. Besides the type specimens, we have seen the following:
BRITISH COLUMBIA. Queen Charlotte Island, Keen (1; ERIC); Masset, Graham Island, Mrs. Clark (1; MCZ); Courtenay, 15 June 35 (1; ERIC); Metchosin, W. Victoria, 29 May 58, Lindroth (1; ERIC).
WASHINGTON. Seattle, King County, 30 June 66, L. Russell (2; UCR).
OREGON. Newport, Lincoln County, 17-21 July, Wickham (1; MCZ); Glenada, Lane County, 20 Aug. 41, B. Malkin (1; FMNH); Glenada, Lane County, 8 June 46, B. Malkin (3; FMNH); Coos Bay, Coos County, 6 Aug. 23, H. Notman (1; ERIC).
CALIFORNIA. Samoa Beach, Humboldt County, 27 Jan. 56, P.S. Bartholomew (8; CAS); San Miguel Island, Santa Barbara County, 20 June 10, V.W. Owen (3; CAS); many specimens from many localities from Marin County to San Diego County throughout the year but mostly from May to August.
MEXICO, BAJA CALIFORNIA NORTE. Many specimens from north of Ensenada mostly in July and August (UCR, ERIC); Ensenada, 31 Mar. 47, B. Malkin (1; FMNH); Ensenada, 3-5 June 05, F.X. Williams (1; CAS); Ensenada, 18 June 19, J.R. Sleven (13; CAS); Ensenada, 5 July 65, E. Schlinger (1; UCR); Ensenada, 16 Aug. 50, I. Moore (1; ERIC); Estero Beach, 20 July 60, I. Moore (1; ERIC); Colonia Guerrero, 28 May 50, I. Moore (5; ERIC); Laguna Santa Maria, 7 Sep. 55, I. Moore (2; ERIC); 15 mi N. Rosario, 1 Aug. 38, Ross & Michelbacher (8; CAS).
2. Cafius canescens (Maklin) Figs. 1B, 5B, 6D-E.
Philonthus canescens Maklin, 1852, Bull. Soc. Imp. Moscow, 25:313.
Cafius canescens (Maklin), Horn, 1884, Trans. Amer. Ent. Soc. 11:235; Casey, 1885, Bull. Calif. Acad. Sci. 1:337 Fig. 4 (pt.); Koch, 1936, Publ. Mus. Ent. Pietro Rossi 1:181 Fig. 2c (pt.), 183; Hatch, 1957, Univ. Wash. Publ. Biol. 16:211, Pl. 27 Fig. 5 (toto); Dvorak, 1957, Ent. News 68:18 Fig. 3-4 (0); James, Moore and Legner, 1971, Trans. San Diego Soc. Nat. Hist. 16:281 Fig. | (larva), 282 (larva), 284 (larva), 285 Fig. 5 (pupa), 288 (pupa); Moore, 1975, Pan-Pac. Ent. 51:140; Orth, Moore and Fisher, 1978, Wasmann Jour. Biol. 35:175 Fig. 4 (toto), 181, 182, 185 (ecology).
Description of lectotype.— Q
Length.—8.\1 mm.
Color.—Largely piceus, with lower edge of elytral epipleura and humeral region pale.
Head.—Quadrate, slightly wider than long, lateral basal angles broadly rounded; eye a little longer than tempora; disc of head impunctate; area behind eyes and narrowly along base with large umbilicate punctures separated by their own diameters or less; disc of head with a shallow central longitudinal impression and a broad shallow circular im- pression on each side between eye and central groove; densely reticulate throughout; undersurface sparsely and coarsely punctured and densely reticulate; gula densely reticulate; antenna distinctly longer than head, 10th segment distinctly transverse.
Pronotum.—Wider than long; apex straight, apical angles rounded, sides nearly straight to broadly rounded basal angles, base gently arcuate; disc largely impunctate except for a longitudinal row of about 15 moderate-sized punctures in a groove on each side of midline; with rather dense setigerous punctures along side margins, particularly anteriorly; surface densely reticulate throughout.
Elytra.—With suture slightly shorter than length of pronotum; each elytron slightly wider than half of sutural length; surface very densely and uniformly punctured throughout.
Abdomen.—More sparsely but as coarsely punctured as elytra; reticulate between punctures, with acrocostal suture straight; pubescence coarse, golden, diagonally arranged near midline and at sides, the latter somewhat in the manner of a cowlick. First 5 visible tergites each with a large impressed puncture centrally on each side of midline.
186
Sternites uniformly punctured and pubescent throughout.
This female from the LeConte collection at MCZ has the right antenna missing beyond the 7th segment and is labeled as follows: “‘canescens Maklin/Kodiak’’, ‘‘J. LeConte/collection’’, ‘‘lectotype/Cafius canescens/Maklin desig. ’78/R.E. Orth, I. Moore.”’
Type locality. —The original description gives the type locality as ‘*‘Insula Edgecombe sub fuscis rejectis’’ (Edgecome Island, beneath wrack.) Because this is the only specimen in the LeConte collection which could be one of Maklin’s cotypes, we have chosen it as the lectotype. In the LeConte collection, there is also 1 male with a gold disc (California), a red label reading ‘‘P. canescens Maklin.’’; another male with a gold disc; a male labeled ‘“‘Cal.’’ with a prominent ink dot under the C; and a male labeled ‘‘Cala.”’
Male characters. —First 4 segments of anterior tarsus broadly dilated. Apical margin of 6th sternite with a large triangular emargination as deep as wide, bottom of the emargination with a membrane with an oval margin. Head of most males larger than in females, in some males also wider than pronotum. Aedeagus differs from that of males of other Pacific coast species in being acutely pointed at its apex. Paramere relatively shorter than in males of other species, being hardly more than 2 the length of the aedeagus.
Female characters. —Anterior tarsus about as widely dilated as in male. Apical margin of 6th sternite entire.
Variation. —The extent of the pale humeral and elytral epipleural area varies slightly. In some specimens, reticulation of the disc of the head and pronotum is not strong.
Notes. —Adults of Cafius canescens and C. seminitens are easily recognized among the Pacific coast species of Cafius by the irregular arrangement of pubescence on the abdomen. In the other species, pubescence is regular and strictly longitudinal. In these 2, the pronotum is wider than long, a condition which occurs otherwise only in some males of C. lithocharinus. Cafius canescens adults differ from C. seminitens adults particularly in the lack of dense pubescence on the 2 terminal sternites, in the shorter antennae, reticulate disc of the head and pronotum, and the straight acrocostal suture.
Description of larva and pupae and notes on ecology were provided by James et al. (1971).
We have seen 5197 specimens.
Distribution.—This species is known from Kodiak, Alaska, to El Tomatal, Baja California Norte, Mexico. Its range undoubtedly extends much farther south along the unexplored coast of Baja California, probably at least to Punta Eugenia, Baja California Sur. It is the commonest species of Cafius in the spring and summer on southern Califor- nia beaches. Adults are abundant in wrack, but can also be seen flying along the beach and alighting on sand. Orth et al. (1978) reported adults at Refugio State Beach, Santa Barbara County, California, in all months of the year except January, but most abun- dantly in the spring. Besides the type specimens, we have seen the following:
ALASKA. Kukal Bay, 5 July 99, T. Kincaid (7; USNM); Mt. Pariat, Alaska Penin- sula, 7 Sep. 13, E.C. Van Dyke (1; ERIC); Propoff Island, 5 July 99, T. Kincaid (11; USNM); Sitka, Liebeck (1; MCZ).
BRITISH COLUMBIA. Courtenay, Gregson (1; CAS); Kyle Bay, 6 May 32, Gregson (3; ERIC); Q{ueen] C[harlotte] Isl[ands], J.H. Keen (1; ERIC); Masset, Graham Island, Mrs. Clark (1; MCZ); Tofino, July 26, Spencer (1; CAS); Vancouver, 23 July 32, H.B. Leech (8; ERIC); Victoria, Hubbard & Schwartz (1; USNM).
WASHINGTON. Many localities mostly in the warm months.
OREGON. Many localities mostly in the warm months.
CALIFORNIA. West Cove, Catalina Island, Los Angeles County, 11-14 July 71, J. Pinto (1; UCR). Many localities, the majority from Marin County to San Diego County, mostly in the warm months.
MEXICO, BAJA CALIFORNIA NORTE. La Mision de San Miguel, May-Aug. 50, I. Moore (257; ERIC); La Salina, July-Aug. 71, I. Moore (1117; UCR); Colonia Guer- rero, 28 May 50, I. Moore (71; ERIC); Colonia Guerrero, 16 Aug. 50, I. Moore (8; ERIC); El Tomatal, 18 June 74, V. Lee (1; CAS).
187
3. Cafius opacus (LeConte) igs. 1C,'5C6E-G:
Philonthus opacus LeConte, 1863, Smith. Misc. Coll. VI, No. 140:40.
Cafius opacus (LeConte), Horn, 1884, Trans. Amer. Ent. Soc. 11:235,239; Koch, 1936, Publ. Mus. Ent. Pietro Rossi, 1:192; Orth, Moore and Fisher, 1978, Wasmann Jour. Biol. 35:176 Fig. 8 (toto), 182, 187 (ecology).
Philonthus dubius LeConte, 1863, Smith. Misc. Coll. VI, No. 140:39.
Cafius dubius (LeConte), Horn, 1884, Trans. Amer. Ent. Soc. 11:244.
Description of lectotype.— 7
Color.—Largely bright reddish-brown with an indistinctly darker area on disc of head near each eye, entire disc of each elytron darker with margins pale, and basal abdo- minal segments nebulously darker.
Head.—Quadrate, somewhat wider than long, lateral basal angles broadly rounded; eye small, about % as long as tempora; punctures of upper surface relatively small, simple, separated mostly by more than their diameters, with a very narrow inconspicuous impunc- tate strip through middle; ground sculpture finely, densely reticulate throughout; under- surface with puncturation and ground sculpture very similar to that above; gula finely and densely reticulate; antenna about % longer than combined lengths of head and pronotum, 10th segment % longer than wide.
Pronotum.—About ¥ longer than wide, apex arcuate, widest near broadly rounded apical angles, sides almost straight but just perceptibly concave before broadly rounded basal angles, base arcuate; surface with simple punctures very similar in size to those of head, regularly arranged from impunctate central area to lateral margin, central impunc- tate area clearly defined and slightly elevated above rest of surface; surface densely and finely reticulate throughout.
Elytra.—With suture about *% length of pronotum; each elytron about *% as wide as sutural length; surface very finely and densely sculptured, punctures hardly noticeable.
Abdomen. —With acrocostal suture straight; surface finely rather densely punctured and reticulate; pubescence fine, longitudinal throughout.
This male in the LeConte collection in MCZ has a gold disc (California) and a small o’ symbol, beneath which is a red label reading ‘‘Type 6291’’ and a white label reading ‘“P. opacus LeC. S.D.’’ We have affixed a yellow label reading ‘‘Lectotype/Cafius opacus/LeConte desig. ’78/R.E. Orth, I. Moore.”’
Type locality.—San Diego, California.
Besides the lectotype, there are 2 males and a female bearing gold discs in the LeConte collection, the males each with a small o symbol. There are also 2 females with ‘““Cala.’’ labels, each with a small check in ink under the letter C. Another pin carries 2 cards, each of which has 2 specimens glued to it and a ‘‘Cal.’’ label with a conspicuous ink dot under the letter C. These last 6 specimens may or may not be a part of the original series.
Male characters. —First 4-segments of anterior tarsus broadly dilated; apical margin of 6th sternite with a large oval emargination surrounded by a narrow membranous margin. Genitalia similar to those of C. bistriatus males but pegs on inner face of paramere more numerous and tightly clustered at apex of paramere than in the latter.
Female characters. —Anterior tarsus about as broadly dilated as in male; apical margin of 6th sternite is entire.
Variation. —Color, particularly of the head, abdomen and sometimes the elytra, varies from bright reddish-brown to dark reddish-brown.
The single male specimen labeled C. dubius LeConte in the LeConte collection has a gold disc (California), a white label reading ‘‘P. dubius LeC. S.D.”’ and a red label reading ‘‘Type 6292.’’ It is a dark specimen of C. opacus. The genitalia have been dissected and are in glycerine in a plastic capsule on the pin. The type locality is “‘San Diego, California,’’ LeConte 1863.
Notes.—Adults of this species are easily distinguished from those of all other Pacific coast species of Cafius, except C. femoralis, by their elongate 10th antennomere. They
188
differ from C. femoralis adults in having shorter elytra in which the suture is shorter than the pronotum. In the latter species, the elytral suture is as long as the pronotum.
The immature stages have not been described.
We have seen 214 specimens.
Distribution.—This species is known from Refugio State Beach, Santa Barbara County, California, to Socorro Dunes, Baja California Norte. Orth et al. (1978) reported adults from Santa Barbara County, California, from September to May. Besides the type specimens, we have seen the following:
CALIFORNIA. Refugio State Beach, Santa Barbara County, R.E. Orth (6) 15 Oct. 76, (2) 8 Nov. 76, (1) 6 Dec. 76, (14) 17 Jan. 77, (9) 7 Feb. 77, (3) 14 Apr. 77, (65) 17 May 77 (UCR); San Pedro, Los Angeles County, Aug., E.C. Van Dyke (1; CAS); San Pedro, Los Angeles County, E.C. Van Dyke (9; CAS); San Pedro, Los Angeles County, 8-11-03, Blanchard (1; MCZ); San Pedro, Los Angeles County, Aug., Wickham (1; USNM); Tor- rey Pines, San Diego County, 7 Apr. 34 (1; ERIC); Torrey Pines, San Diego County, 15 Nov. 50, I. Moore (1; ERIC); La Jolla, San Diego County, 22 Nov. 50, I. Moore (1; ERIC); Point Loma, San Diego County, 28 Dec. 28, E.C. Van Dyke (19; CAS); San Diego, San Diego County, F.E. Blaisdell (11; CAS); San Diego, San Diego County, 23 May 27 (1; CAS); Coronado, San Diego County, 7 June 90, F.E. Blaisdell (1; CAS).
MEXICO, BAJA CALIFORNIA NORTE. Rio San Telmo, 16 June 38, Ross & Michelbacher (70; CAS); Socorro Dunes, 17 July 74, R.M. Haradon, V. Lee & W.E. Savary (1; UCR).
4. Cafius femoralis (Maklin) Figs. 1D, 5D, 7A-B.
Philonthus femoralis Maklin, 1852, Bull. Soc. Imp. Moscow 25:189.
Cafius femoralis (Maklin), Horn, 1884, Trans. Amer. Ent. Soc. 11:235, 238; Casey, 1885, Bull. Calif. Acad. Sci. 1:337 Fig. 5 (pt.); Koch, 1936, Publ. Mus. Ent. Pietro Rossi 1:199; Hatch, 1957, Univ. Wash. Publ. Biol. 16:210, 355 Pl. 27 Fig. 2 (toto).
Cafius mutatus Gemminger and Harold, 1868, Cat. Coleopt. 2:590.
Description of lectotype.— o
Length.—5.8 mm.
Color.—Head black, pronotum and abdomen dark brown, elytra slightly paler, femora and tarsi pale brown, tibiae dark brown, mouth parts and base of antenna dark brown, antenna progressively paler toward apex.
Head.—Quadrate, about as long as wide, basal angles broadly rounded; eye more than half as long as tempora; punctures of upper surface small, separated by about their diameters, with a central longitudinal impunctate area along length of head; ground sculpture finely, densely reticulate; undersurface finely and densely punctured and reticulate; gula densely reticulate; antennae distinctly longer than combined lengths of head and pronotum; 10th segment %, longer than wide (contrary to statements by Horn 1884, pp. 235, 238).
Pronotum.—Longer than wide; apex broadly rounded; widest near broadly rounded apical angles, thence narrowed with sides nearly straight to the somewhat narrowly rounded basal angles; base arcuate; surface with evenly placed dense small punctures except for central longitudinal impunctate area, densely reticulate except for a small tumid area in middle at base.
Elytra.—With suture a little shorter than length of pronotum; surface so finely and densely sculptured that punctures hardly visible.
Abdomen.—With acrocostal suture nearly straight; finely rather densely punctured and reticulate; pubescence fine, longitudinal throughout; undersurface uniformly punc- tured and pubescent. Apex of 6th sternite with a triangular emargination which is about as wide as deep, the base of which has a membrane with an oval emargination.
This male has a gray disc, a male symbol, a white square reading ‘‘177’’, a red label reading ‘‘Type 7330’’, a large white label reading ‘‘Philonthus femoralis/Maklin/ Kodiak’’, a label reading ‘‘LeConte/collection’’, and one reading ‘‘Lectotype/Cafius
189
femoralis/Maklin desg. ’78/R.E. Orth, I. Moore.’’ One other specimen, a female, in the LeConte collection has a label reading ‘‘maritimus Mots. Kodjak’’ and a ‘‘LeConte col- lection’’ label.
Type locality.—Kodiak Island, Alaska.
Male characters.—Anterior tarsus broadly dilated. Apical margin of 6th sternite with deep triangular emargination with a membrane at its bottom. Genitalia similar to those of Cafius luteipennis males; but paramere with 10 pegs on its inner face rather than 6 as in members of the latter species.
Female characters.—Anterior tarsus almost as broadly dilated as in male. Apical margin of 6th sternite entire.
Variation. —There is little variation among the specimens seen by us.
Notes.—Cafius femoralis and C. opacus are unique among Pacific coast species in having the 10th antennal segment longer than wide. In C. opacus adults, the elytral suture is distinctly shorter than the pronotum, whereas in C. femoralis adults, it is fully as long as the pronotum.
The immature stages have not been described.
We have examined 239 specimens.
Distribution.—This species is known from Alaska to Carmel, Monterey County, California. Besides the type specimens, we have seen the following:
ALASKA. Haines, 3 June 68, Campbell & Smetana (30; ERIC); Kodiak (1; MCZ).
BRITISH COLUMBIA. Q[ueen] C[{harlotte] I[sland], [Keen], (4; ERIC); Masset, Graham Island (1; MCZ); Bowser, 12 June 55, W.J. Brown (25; ERIC); Pacific Rim, N.P. Michigan Cr., 12 July 75, M. & B. A. Campbell (23; ERIC); Metchosin, West Vic- toria, 29 May 58, Lindroth (1; ERIC); Victoria, Hubbard & Schwarz (1; USNM).
WASHINGTON. Port Angelus, Clallam County, 28 May 07, E.C. Van Dyke (18; CAS).
OREGON. Cannon Beach, Clatsop County, 15 June 27, E.C. Van Dyke (1; CAS).
CALIFORNIA. Bear Harbor, Mendocino County, D. Giuliani (6; ERIC); Needle Rock, Mendocino County, 6 Oct. 74, D. Giuliani (4; UCR); Mouth of Russian River, Sonoma County, Jan. 70, D. Giuliani (1; UCR); Carmel, Monterey County, 4 Feb. 17, L.S. Slevin (1; CAS); Carmel, 28 Mar. 22, (22; CAS); Carmel, 13 Apr. 13, L.S. Slevin (1; CAS); Carmel, 21 May 11, E.C. Van Dyke (1; CAS).
5. Cafius lithocharinus (LeConte) Figs. 2A, 7C-D.
Philonthus lithocharinus LeConte, 1863, Smith. Misc. Coll. VI, No. 140:38.
Cafius lithocharinus (LeConte), Horn, 1884, Trans. Amer. Ent. Soc. 11:23, 236; Koch, 1936, Publ. Mus. Ent. Pietro Rossi 1:193; Hatch, 1957, Univ. Wash. Publ. Biol. 16:210, 235 Pl. 27 Fig. 2 (toto); James, Moore and Legner, 1971, Trans. San Diego Soc. Nat. Hist. 16:282 (larva), 288 (pupa); Leech and Moore, 1971, Wasmann Jour. Biol. 29:66 (ecology); Moore, 1975, Pan-Pac. Ent. 51:140 (larva); Orth, Moore and Fisher, 1978, Wasmann Jour. Biol. 35:175, Fig. 6 (toto), 182, 183, 186 (ecology).
Description of lectotype.— o
Color.—Largely piceous with, near inner apical angle of each elytron, a buff to reddish-brown nearly circular spot extended to apical margin but not to suture. Sixth and 7th visible tergites and cerci reddish-brown; 4th sternite with a small reddish-brown area on each side near base and a similar transverse band near apical margin, Sth sternite large- ly reddish-brown with lateral and apical margins piceous, 6th and 7th sternites reddish- brown. Elytral epipleura buff colored. Legs reddish-brown.
Head. —Quadrate, slightly wider than long, lateral basal angles broadly rounded; eye 4 length of tempora; punctures of upper surface large, umbilicate, largely separated by about their diameters, somewhat more crowded at base; with an impunctate area adjacent to clypeal margin connected narrowly with a broad central impunctate area; ground sculpture finely, densely reticulate throughout; undersurface roughly sculptured with
190
large coarse coalescent punctures arranged in diagonal rows, gula densely and finely reticulate; antenna slightly shorter than combined lengths of head and pronotum, 10th segment slightly wider than long.
Pronotum.—About as wide as long; apex broadly rounded; widest near broadly rounded apical angles, thence narrowed with lateral margins slightly concave to the broadly rounded basal angles; base arcuate; surface with simple punctures separated by less than their diameters, somewhat smaller and more crowded than those of head; central impunctate area clearly defined; not elevated except very slightly in a small area near base; surface densely reticulate and dull throughout except for small, somewhat shiny basal area.
Elytra.—With suture slightly shorter than length of pronotum; each elytron *%4 as long as sutural length; surface very finely, uniformly densely, somewhat roughly punc- tured; finely reticulate between punctures.
Abdomen.—Finely and more sparsely punctured than elytra; finely reticulate between punctures. Acrocostal sutures straight. Pubescence fine, longitudinal throughout. Undersurface uniformly punctured and pubescent throughout.
This large male in the LeConte collection at MCZ has the left antenna missing beyond the 3rd segment. Below the specimen, a gold disc (California) and a small o sym- bol are attached. We have added a label reading ‘‘Lectotype/Cafius lithocharinus/ LeConte desig. ’78/R.E. Orth, I. Moore.”’
Type locality.—San Diego, California.
Besides the lectotype, there are 2 males and | female in the LeConte collection bear- ing gold discs. One of the males has a white label reading ‘‘P. lithocharinus LeC. Si Dx and ared label reading ‘‘Type 6288.’’ The LeConte collection also includes 2 males and 3 females labeled ‘‘Cal’’ and 1 female labeled ‘‘Cal’’ with a conspicuous ink dot under the C. These last 6 specimens may not be part of the original type series.
Male characters. —First 4 segments of anterior tarsus broadly dilated. Apical margin of 6th sternite with triangular emargination about as deep as wide, emargination partly filled by membrane with an oval emargination. Genitalia most similar to those of C. femoralis males. However, aedeagus not as strongly tapered at apex and paramere some- what longer in relation to aedeagus than in C. femoralis males.
Female characters. —Head about as wide as pronotum, anterior tarsus almost as broadly dilated as in male and 6th sternite simple.
Variation. —Color, particularly that of the elytra, is variable. Rarely is the disc of the elytra entirely piceous. The buff colored spot may be variously enlarged or may extend across the entire apex of the elytra, or, in few specimens, even forward to cover the entire elytron. In the latter case, the specimen will resemble Cafius /uteipennis adults; but the elytra have a more reddish cast compared with the yellowish cast of C. /uteipennis adult elytra. The legs and abdomen are variably darker in some specimens. Size of the head and pronotum of males varies considerably. In some males, such as the lectotype, the head is much wider than the pronotum, in which case, the pronotum is also wider than usual, about as wide as long. In other males, the head is variably narrow until it may be no wider than pronotum in which case the pronotum is longer than wide. In females, the head is always about as wide as the pronotum, which is longer than wide. In some females, the punctures on the undersurface of the head are not strongly coalescent.
Notes.—Most specimens of Cafius lithocharinus can be recognized by the pale apical margin of the elytra; but, as mentioned above, some individuals have the elytra entirely piceous or entirely pale. The sculpture of the undersurface of the head readily distinguishes members of this species from all other Pacific coast species; the punctures are very large, deeply impressed and crowded in diagonally arranged short rows of coelescing punctures. The sculpture of the undersurface of the head is coarse and rough.
The larvae, pupae and ecology were described by James et al. (1971).
We have examined 5506 specimens.
Distribution. —This species is known from British Columbia to Cedros Island, Baja California del Norte, Mexico. According to Orth et al. (1978), adults were abundant in wrack at Refugio State Beach, Santa Barbara County, California, from September
19]
through March but not from April to August. They said, ‘‘It is known to fly in swarms along the beach in winter probably on dispersal flights (Leech and Moore 1971); and at such times can be found under almost every bit of debris on the beach. Flights look decep- tively like swarms of flies.’’ Besides the type series, we have seen the following specimens:
BRITISH COLUMBIA. Pacific Rim, Klanawa River, 14 July 75, J.M. & B.A. Campbell (117; ERIC).
WASHINGTON. 2 mi. n. La Push, Clallam County, 17 Oct. 74, D. Giuliani (1; UCR); Kaloloch, 3 Sept. 34, A.L. Melander (1; MCZ).
CALIFORNIA. Sonoma, Sonoma County, June 27, Ricksecker (1; FMNH); many spms., many localities from Marin County to San Diego County, mostly from Sep. to May.
MEXICO, BAJA CALIFORNIA NORTE. Rosarito Beach, 27 May 50, I. Moore (34; ERIC); Descanso Bay, 29 May 50, I. Moore (1; ERIC); La Mision de San Miguel, 27 May 50, I. Moore (3; ERIC); La Salina, var. dates June-Aug. iL, ls Moore. (G5; UCR): Ensenada, 16 Aug. 50, I. Moore (1; ERIC); Rio San Telmo, 15 June 38, Ross & Michel- bacher (1; CAS); Camalu Point, San Ramon Bay, 19 June 39, Harbison & Bildebeck (2; UCR); Colonia Guerrero, 28 May 50, I. Moore (15; ERIC); 15 m. n. Rosario, | Aug. 38, Ross & Michelbacher (14; CAS); Estero Rosario, 25 Apr. 68, P. Arnaud (95; CAS); n. end Cedros Island, 27 Mar. 53, J. Figg-Hoblyn (1; ERIC.)
6. Cafius luteipennis Horn Figs. 2B, 7E-F
Cafius luteipennis Horn, 1884, Trans. Amer. Ent. Soc. 11:235, 237; Koch, 1936, Publ. Mus. Ent. Pietro Rossi, 1:191; Hatch, 1957, Univ. Wash. Publ. Biol. 16:211, 3)5)5) Ee 27 Fig. 3 (toto); James, Moore and Legner, 1971, Trans. San Diego Soc. Nat. Hist. 16:282 (larva), 284 Fig. 3 (larva), 287 Fig. 7 (pupa); Moore, 1975, Pan-Pac. Ent. 51:140 (larva); Orth, Moore and Fisher, 1978, Wasmann Jour. Biolis5275 Figs 7 (toto), 182, 183, 186 (ecology).
Description of lectotype.— 2
Color.—Piceus with elytra bright buff.
Head.—Quadrate, about as wide as long, lateral basal angles broadly rounded; eye about % as long as tempora; punctures large umbilicate, mostly separated by their diameters or less; disc with a small irregularly defined impunctate area; reticulate between punctures; undersurface with large evenly spaced weakly impressed punctures throughout; antennae almost as long as combined lengths of head and pronotum, 10th segment a little wider than long.
Pronotum.—Somewhat longer than wide; apex nearly straight, widest near broadly rounded apical angles, thence narrowed with lateral margin very slightly concave to broadly rounded basal angles; base arcuate; surface with simple punctures mostly spaced about as on head, with a broad central longitudinal impunctate area and a small irregular- ly shaped impunctate area on each side near the apex adjacent to line of punctures which delimits the central impunctate space; surface densely reticulate throughout.
Elytra.—With suture shorter than length of pronotum, each elytron 2 as wide as sutural length; surface finely, densely punctured, reticulate between punctures.
Abdomen. —With acrocostal sutures straight; finely and more sparsely punctured than elytra, finely reticulate; pubescence fine, longitudinal throughout. Sternites uniform- ly punctured and pubescent.
This male from the Horn collection in MCZ bears the following labels: a @alhes “Horn coll/H2261” and ‘“‘Lectotype/Cafius luteipennis/Horn desig. ’78/R.E. Orth, I. Moore.”’
Besides the lectotype, there are 9 specimens with the same data as the lectotype in the Horn collection, 1 of which also bears a label reading ‘‘PhA. luteipennis LeC.”’ (Sic!). The LeConte collection also contains the following specimens: 1 female with labels reading ‘“<Cal”’ underlined in red ink, a red label reading ‘‘Type/7329”’ and a “‘C. luteipennis J.
192
LeC.”’ (Sic!) label; a male with a ‘‘Cal’’ label with an ink dot under the C; a female with a ‘“‘Cala.’’ label and a female with a ‘‘Cal’’ label underlined with red ink.
Male characters. First 4 segments of anterior tarsus broadly dilated. Apical margin of 6th sternite with a shallow oval emargination with a membranous border. Aedeagus most similar to that of C. femoralis males, but differs particularly in having only 6 pegs at inner apex of paramere instead of 10 as in the latter.
Female characters. —Anterior tarsus about as broadly dilated as in male. Apical margin of 6th sternite entire.
Variation. —There appears to be very little variation among the specimens examined. A few males have the head a little larger than that of females.
Notes.—Adults of this species are easily recognized among Pacific coast Cafius by their bright buff colored elytra. A few specimens of C. lithocharinus have clear, bright golden elytra; but in these, the punctures on the underside of the head are large and coalescent in diagonal rows. In C. /uteipennis adults, the punctures of the undersurface of the head are always discrete.
Description of larvae and pupae and notes on ecology were provided by James et al. (1971).
We have examined 885 specimens.
Distribution.—This species is known from British Columbia, Canada, to El Tomatal, Baja California del Norte, Mexico; but undoubtedly it will eventually be found to extend farther south along the unexplored coast of Baja California. Orth et al. (1978) reported it from Refugio State Beach, Santa Barbara County, California, as most abun- dant from September through May. Besides the type specimens, we have seen the follow- ing:
BRITISH COLUMBIA. Masset, Graham Island, 1918, Mrs. Clark (1; MCZ); Q[ueen] C[harlotte] I[slands], [Keen] (7; ERIC); Miracle Beach, Vancouver Island, 22 Aug. 75, J.M. & B.A. Campbell (3; ERIC); Parkville, 23 Nov. 38, H. Andison (2; ERIC); Victoria, Coquillett (3; USNM).
WASHINGTON. 2 mi. n. La Push, Clallam County, 17 Oct. 74, D. Giuliani (1; UCR).
OREGON. Whitehead Beach, Curry County, 6 July 74, A. Newton & M. Thayer (2; MCZ).
CALIFORNIA. Haversneck, Mendocino County, D. Giuliani (1; ERIC); Mouth of Russian River, 4 July 08, Van Dyke (1; ERIC); Avalon, Santa Catalina Island, Los Angeles County, KWH (1; USNM); many specimens, many localities between Marin and San Diego counties, mostly from October to April.
MEXICO, BAJA CALIFORNIA NORTE. Descanso Bay, 27 May 50, I. Moore (3; ERIC); La Salina, 22 July 71, I. Moore (2; UCR); Colonia Guerrero, 16 Aug. 50, I. Moore (4; ERIC); Socorro Dunes, 17 July 74, R.M. Haradon, V. Lee and W.E. Savary (1; UCR); Rosario, 1 Aug. 38, Ross & Michelbacher (2; CAS); Arroyo Rosario, 25 Apr. 63, P. Arnaud (3; CAS); El Tomatal, 18 July 74, R.M. Haradon, V. Lee and W.E. Savary G2UER):
7. Cafius decipiens (LeConte) Figs. 2C, 7G-H.
Philonthus decipiens LeConte, 1863, Smith. Misc. Coll. VI, No. 140:40. Cafius decipiens (LeConte), Horn, 1884, Trans. Amer. Ent. Soc. 11:235, 239; Koch, 1936, Publ. Mus. Ent. Pietro Rossi, 1:190.
Description of lectotype.— o
Length.—7.7 mm.
Color.—Head dark reddish brown, remainder of body and appendages a paler uniform reddish brown.
Head.—Quadrate, slightly wider than long, basal angles broadly rounded; eye “2 length of tempora; punctures of upper surface moderate sized, not conspicuously umbili-
193
cate, separated mostly by about their own diameters; with a central impunctate area extending from clypeal margin to near base; ground sculpture densely reticulate through- out; undersurface with punctures and ground sculpture very much like that above; gula densely reticulate; antennae a little longer than combined lengths of head and pronotum; 10th segment slightly wider than long.
Pronotum.—Somewhat longer than wide; apex broadly rounded, widest near broad- ly rounded apical angles, thence narrowed and straight to broadly rounded basal angles; base arcuate; surface with simple punctures about same size as those of head, separated by about their own diameters; central impunctate area clearly defined and hardly elevated except for a small basal tumid area; surface densely reticulate and dull throughout.
Elytra.—With suture about % shorter than pronotum; each elytron % as wide as sutural length; surface very finely densely sculptured, punctures hardly distinguishable.
Abdomen.—Finely, rather sparsely punctured and finely reticulate, with acrocostal suture straight. Pubescence fine, longitudinal throughout.
This male in the LeConte collection at MCZ bears a gold disc (California) and a small o symbol. Beneath this is a plastic capsule containing the genitalia in glycerine. We have attached a label reading ‘‘Lectotype desg. Cafius decipiens/LeConte 1978, Orth and Moore.”’
Type locality.—San Diego, California.
Besides the lectotype, 1 male (with sex symbol attached) and 1 female, both with gold discs are in the LeConte collection. The female also has a white label reading ‘‘P. deci- piens LeC. S.D.”’ and a red label reading ‘‘Type 6290.’’ There are also 1 male and 3 females, each with a white label reading ‘‘Cal.’’, the male also with a small sex symbol. These last 5 specimens may not be part of the original type series.
Male characters.—First 4 segments of anterior tarsus somewhat broadly dilated. Apical margin of 6th sternite with a broad deep oval emargination surrounded by a fairly wide membranous border. Genitalia most similar to those of Cafius sulcicollis males, but aedeagus strongly constricted in apical third, then abruptly widened, resembling shoulders. In C. sulicollis males, aedeagus slipper-shaped, without a trace of shoulders at apical third.
Female characters. —First 4 segments of anterior tarsus about as broadly dilated as in male. Apical margin of 6th sternite entire.
Variation.—The specimens seen by us show little variation.
Notes.—Members of this species closely resemble those of C. sulcicollis but can be distinguished by their reddish-brown head, which is black in C. sulcicollis adults. The eye is almost exactly 2 the length of the tempora whereas in C. sulciocollis adults the eye is noticeably longer than 2 the length of the tempora. Males of this species differ strikingly from those of the other Pacific coast Cafius species in the shape of the aedeagus, which is strongly constricted in its apical third. Male genitalia are relatively larger than those of the other Pacific coast species.
Nothing is known of the life history or ecology of this species.
We have seen 34 specimens.
Distribution.—This species is known from San Pedro, Los Angeles County, Califor- nia, to 24 kilometres north of Rosario, Baja California Norte, Mexico. The single specimen listed below from Mexico is the only one with a collection date. All California specimens were probably collected near or before the turn of the century. Besides the type series we have seen the following specimens:
CALIFORNIA. Cal., F.A. Eddy (2; MCZ); Cal., Hubbard & Schwarz (3; USNM); San Pedro, Los Angeles County, July, A. Fenyes (2; CAS); San Pedro, Los Angeles County, Aug., A. Fenyes (1; CAS); San Diego County, F.E. Blaisdell (1; CAS); San Diego, San Diego County (1; MCZ); [San Diego Bay, Spring], T.L. Casey (see Casey 1885:312) (10; USNM); San Diego, Hubbard & Schwarz (5; USNM).
MEXICO, BAJA CALIFORNIA NORTE. 15 mi. n. Rosario, 1 Aug. 38, Ross & Michelbacher (1; CAS).
194
8. Cafius sulcicollis (LeConte) Figs. 2D, 8A-B.
Philonthus sulcicollis LeConte, 1863, Smith. Misc. Coll. VI, No. 140:40.
Cafius sulcicollis (LeConte), Horn, 1884, Trans. Amer. Ent. Soc. 11:235, 237; Koch, 1936, Publ. Mus. Ent. Pietro Rossi, 1:191; Leech and Moore, 1971, Wasmann Jour. Biol. 29:65 (ecology); Orth, Moore and Fisher, 1978, Wasmann Jour. Biol. 35:176 Fig. 9 (toto), 182, 187 (ecology).
Description of lectotype.— 7
Length.—5.8 mm.
Color.—Head and metasternum black, remainder of body and appendages reddish- brown.
Head. —Quadrate, slightly wider than long, lateral basal angles broadly rounded; eye distinctly more than 2 as long as tempora; puncturation of upper surface just discernably umbilicate, most punctures separated by about their own diameters, slightly more crowd- ed at base, with an impunctate area adjacent to clypeal margin and a small impunctate central area; ground sculpture densely reticulate throughout; undersurface with punctura- tion and ground sculpture very similar to that above; gula densely, finely reticulate; antenna very slightly shorter than combined lengths of head and pronotum; 10th segment slightly wider than long.
Pronotum.—Distinctly longer than wide, apex arcuate, widest near broadly rounded apical angles, sides slightly concave before broadly rounded basal angles, base arcuate; surface with simple punctures evenly placed, about same size as those of head; central impunctate area somewhat irregularly defined by punctures but demarked on each side by a shallow sulcus; surface densely reticulate throughout except for a very small shining area in middle near base.
Elytra.—With suture as long as pronotum; each elytron about *%4 as wide as sutural length. Surface very finely, densely, and asperately punctured.
Abdomen.—Finely, sparsely punctured, finely reticulate between punctures, with acrocostal suture straight. Pubescence fine, longitudinal throughout.
This male in the LeConte collection at MCZ has beneath it a gold disc (California) and a small o& symbol. Below this is a plastic capsule containing the genitalia in glycerine and a label reading ‘‘Lectotype/Cafius sulcicollis/LeConte desig. ’78/R.E. Orth, I. Moore.’’
Type locality.—San Diego, California.
Besides the lectotype, there are 3 females with gold discs in the LeConte collection, one of which also bears a white label reading ‘‘P. su/cicollis LeC., S.D.’’, and a red label reading ‘‘Type 6289.’’ One male in the LeConte collection, but possibly not part of the original type series, has a white label reading, ‘‘Cal.’’ underlined in red ink; and another male has a ‘‘Cal.’’ label with a distinct ink dot below the C.
Male characters. —First 4 segments of anterior tarsus broadly dilated. Apical margin of 6th sternite with an oval emargination, about as deep as wide and nearly filled with membrane. Genitalia most similar to those of C. /uteipennis males. They differ most noticeably from the latter in that the middle tumescence is distinctly closer to the basal attachment of the paramere than to the apex of the paramere; whereas, in the latter it is very nearly centrally placed.
Female characters.—First 4 segments of anterior tarsus are about as broadly dilated as in male and apical margin of 6th sternite entire.
Variation. —Very little variation has been detected.
Notes.—Adults of this species are easily distinguished from those of other Pacific coast Cafius species except C. decipiens by the combination of the transverse 10th anten- nomere, the longitudinal abdominal pubescence, the simple puncturation of the under- surface of the head and the uniformly punctured sides of the pronotum. They differ from C. decipiens adults in having a black head and longer eye. The eye is more than 2 the length of the tempora. In C. decipiens adults, the head is reddish-brown and the eye is almost exactly 2 as long as the tempora.
195
The immature stages have not been described. Larva described as belonging to this species and records of this species from the Salton Sea, Imperial County, California, and Sonora, Mexico, by Moore (1974, 1975) and Moore and Legner (1973) actually represent Cafius bistriatus (Erichson).
We have examined 213 specimens.
Distribution. —This species has been reported from Refugio State Beach, Santa Bar- bara County, California (Orth et al. 1978) to Magdalena Island, Baja California Sur, Mexico (Horn 1894). The Magdalena Island specimen has not been seen by us. There is a single female in the collection of the University of California, Riverside, which we doubt- fully place here, collected by Derham Giuliani 3.2 kilometres north of La Puch, Clallam County, Washington, 17 October 1974. Orth et al. (1978) reported this as the least abun- dant of the Cafius species found at Refugio State Beach, Santa Barbara County, Califor- nia, but only slightly less so than C. opacus. Furthermore, it is a winter species found chiefly from October to May. Leech and Moore (1971) reported adults in flight on the beach in Baja California and San Diego, California.
Besides the type series we have seen the following specimens:
CALIFORNIA. Gaviota, Santa Barbara County, 20 Sept. 50, I. Moore (1; ERIC); Refugio State Beach, Santa Barbara County, R.E. Orth, (4) 8 Nov. 76, (9) 6 Dec. 1655) 17 Jan. 77, (6) 7 Feb. 77, (2) 14 Mar. 77, (4) 12 Apr. 77. (1) 17 May 77, (1) 2 Aug. 77, (1) 8 Sept. 77 (UCR); Frazier Point, Santa Cruz Island, 8 Jan. 71, J. Pinto, Chearey, R. Somerby (1; UCR); Santa Barbara, Santa Barbara County, June, A. Fenyes (icCAS): Redondo, Los Angeles County, Apr., A. Fenyes (1; CAS); Redondo, Los Angeles County, July, A. Fenyes (1; CAS); San Pedro, Los Angeles County, Aug., A. Fenyes (2; CAS); San Pedro, Los Angeles County (1; FMNH); Los Angeles, Los Angeles County, Coquillett (1; USNM); Laguna Beach, Orange County, Baker (1; FMNH); Cardiff, San Diego County, 21 Aug. 71, G. Olton & I. Moore (1; UCR); Torrey Pines, San Diego County, 22 May 55, I. Moore (1; UCR); La Jolla, San Diego County, 11 Apr. 34, I. Moore (1; CAS); La Jolla, 22 Apr. 51, I. Moore (30; ERIC); La Jolla, 29 Aug. SO eels Moore (29; ERIC); La Jolla, 22 Sept. 53, I. Moore (2; ERIC); La Jolla. 22°Octs505 1: Moore (1; ERIC); La Jolla, 22 Nov. 50, I. Moore (84; ERIC); Sunset Cliffs, San Diego County, 23 Aug. 50, I. Moore (1; ERIC); Sunset Cliffs, San Diego County, 5 Oct. 53, I. Moore (1; ERIC); Ocean Beach, San Diego County, 2 Sept. 50, I. Moore (3; ERIC); Mis- sion Bay, San Diego County, 25 Sept. 53, I. Moore (1; ERIC); San Diego Bay, San Diego County, 2 Sept. 50, I. Moore (26; ERIC); Point Loma, San Diego County, 28 Dec. 28, E.C. Van Dyke (1; ERIC); San Diego, San Diego County, May, A. Fenyes (1; ERIC); San Diego, A. Watson (1; ERIC); North Island, San Diego County, 2 Mar. 30, I. Moore (1; ERIC); North Island, San Diego County, 6 Apr. 38, I. Moore (1; ERIC).
MEXICO, BAJA CALIFORNIA NORTE. Colonia Guerrero, 28 May 50, I. Moore (10; ERIC); 15 mi. n. Rosario, 1 Aug. 35, Ross & Michelbacher (1; CAS); Arroyo Rosario, 25 Apr. 63, P. Arnaud, (1; CAS).
9. Cafius bistriatus (Erichson) Figs. 3A, 5E, 8C-D, 10
Philonthus bistriatus Erichson, 1840, Gen. Spec. Staph. 502.
Philonthus bilineatus Erichson, 1840, Gen. Spec. Staph. 503.
Cafius bistriatus (Erichson), Horn, 1884, Trans. Amer. Ent. Socteli=235e237-aKoch 1936, Publ. Mus. Ent. Pietro Rossi, 1:175, 187; Blackwelder, 1943, Bull. U.S. Nat. Mus. 182:436, 438.
Cafius bilineatus (Erichson), Koch, 1936, Publ. Mus. Ent. Pietro Rossi 1:176, 187.
Cafius sulcicollis (LeConte), Moore, 1975, Pan-Pac. Ent. 51:140 (larva), Fig. 1-4 (larva), 142 (larva).
Description of male.—From El Desemboque, Sonora, Mexico. Length.—6.5 mm.
196
Color.—Head black, remainder of body dark reddish-brown with antenna gradually paler to apex.
Head.—Quadrate, about as wide as long, lateral basal angles broadly rounded; eye distinctly shorter than tempora; punctures of upper surface moderate-sized, umbilicate, separated by more than their own diameters, with an irregular impunctate central area the length of head; surface densely reticulate at sides, weakly so in very center of disc; under- surface uniformly punctured with ground sculpture very similar to that above; gula densely reticulate; antennae a little shorter than combined lengths of head and pronotum, 10th segment slightly wider than long.
Pronotum.—Longer than wide, apex broadly rounded, widest near broadly rounded apical angles, thence narrowed and nearly straight to the broadly rounded basal angles, base arcuate; surface with a broad longitudinal impunctate area bounded on each side by arow of 16 or 17 large equidistant punctures, and with a narrow irregular impunctate area lateral to same almost as long as pronotum; sides somewhat evenly punctured to lateral margin; surface reticulate at sides, reticulation becoming very feeble in central impunctate area.
Elytra.—With suture slightly longer than pronotum; each elytron *% as wide as sutural length; surface distinctly and very densely punctured, punctures separated by less than their own diameter, very finely reticulate between punctures.
Abdomen.—Almost as densely punctured as elytra, punctures asperate; acrocostal sutures straight; without ground sculpture; pubescence fine, longitudinal throughout. Undersurface uniformly punctured and pubescent throughout.
Type locality.—Long Island, New York.
Male characters. —Anterior tarsus broadly dilated. Apical margin of 6th sternite with a shallow triangular emargination partly filled by membrane. Genitalia most similar to those of Cafius sulcicollis males; but aedeagus more pointed at apex, and paramere relatively shorter. Middle tumescence of aedeagus located very near to middle of paramere, rather than at about the basal 4 of the paramere as in C. sulcicollis males.
Female characters.—Anterior tarsus almost as broadly dilated as in male. Apical margin of 6th sternite entire.
Variation.—In some males, the head is slightly larger than in the females. Most west coast specimens have the tibiae a little darker than the femora and tarsi. The color of west coast specimens is otherwise fairly consistent except for an occasional specimen which is slightly darker.
Notes.—Adults of this species closely resemble those of Cafius sulcicollis and were reported as that species from the Salton Sea by Moore and Legner (1973) and from Sonora, Mexico, by Moore (1974). Western specimens differ from C. sulcicollis specimens in the shining surface with weak or absent reticulation of the central impunctate area of the pronotum; that area in C. sulcicollis adults is as strongly reticulate as the sides of the pronotum and the head. In all C. bistriatus specimens from western North America, there is always a prominent shiny impunctate area just lateral to the row of punctures which delimit the central impunctate area of the pronotum; such an area is rarely present in C. sulcicollis specimens, and when present it is dull due to strong reticulation. The punctures of the elytra in C. bistriatus adults are distinctly separated and not asperate, whereas in C. sulcicollis members they are asperate and tend to run together in weak lateral ridges so that the individual punctures are not easily seen. The color of western specimens of C. bistriatus, except for the black head, is usually bright reddish-brown, whereas C. sulcicollis members are usually dark brown.
The aedeagus of Cafius bistriatus is more pointed at the apex than that of C. sulcicollis; and the paramere is relatively shorter.
The larva was described by Moore (1975) as that of C. sulcicollis.
We have examined 480 specimens from western North America and 740 specimens from eastern North America.
Distribution.—This species was originally described from Long Island, New York, and has been recorded from various localities along the eastern seashore of the United States from Massachusetts to Florida, numerous localities in the West Indies and from
197
South America. We present here a first record from the west coast of North America. In that area, it is known from Desert Beach, Salton Sea, Riverside County, California, through almost the entire Gulf of California to Isla San José, Baja California Sur, near LaPaz, and from 63 kilometres north of Guerrero Negro, Baja California Norte on the Pacific coast of Baja California. We have seen the following specimens from western North America:
CALIFORNIA. Desert Beach, Salton Sea, Riverside County, 3 Mar. 68, K. Cooper (3; UCR).
MEXICO, SONORA. Punta Penasco, 7 June 74, algae covered rock with small bar- nacles, V. Roth (1; ERIC); Punta Cirio, 29.50-112.40, wrack on sandy beach, V. Roth & W. Brown (99; UCR); near Punta Cirio, 28 Aug. 74, V. Roth & W. Brown (88; UCR); El Desemboque de Los Seris, 1 June 74, W. Brown (5; UCR); Tepoca, 29.18-112.20, wrack on sandy beach, V. Roth & W. Brown (2; UCR); Punta Chueca, 29.00-112.05, light trap on sandy beach, 18 Jan. 75, V. Roth (3; UCR); Punta Doble, 26 Feb. 74, P. DeBach & M. Rose (1; UCR); Huatabampo, D. Giuliani (1; UCR).
MEXICO, BAJA CALIFORNIA NORTE. 39 mi. n. Guerrero Negro on road to Miller’s Landing, 8 Aug. 74, R. Haradon, V. Lee & E. Savary (6; UCR).
MEXICO, BAJA CALIFORNIA SUR. Santa Rosalia, 20 July 74, R.H. Haradon, V. Lee & E. Savary (1; UCR); Isla San José, 19 Apr. 72, rotting fish, L. Cheng (2; UCR).
10. Cafius caribeanus Bierig Figs. 3B, 8E-F.
Cafius corallicola var. caribeanus Bierig, 1934, Revista Ent. 4:67, 68; Koch, 1936, Publ. Mus. Ent. Pietro Rossi 1:175, 176, 186. Cafius caribeanus Bierig, Blackwelder, 1943, Bull. U.S. Nat. Mus. 182:436, 437.
Description of male.—From San Blas, Nayarit, Mexico.
Length.—5.0 mm.
Color.—Head and pronotum black, elytra piceus, abdomen dark reddish-brown, legs and trophi paler than abdomen, antenna gradually paler toward apex.
Head.—Quadrate, almost as wide as long, basal angles moderately broadly rounded; eyes as long as tempora; punctures of upper surface coarse, separated at sides by about their own diameters, with a small impunctate discal area, and a central linear longitudinal impression in apical half; surface sculpture of fine wavy, lines in a dactylographic pattern; undersurface with punctures and surface sculpture similar to that above; gula sculptured with fine wavy dactylographic lines; antenna as long as combined lengths of head and pro- notum, 10th segment about as long as wide.
Pronotum.—Longer than wide, apex arcuate, widest near broadly rounded apical angles, thence narrowed and nearly straight to broadly rounded basal angles, base arcu- ate; surface with a broad longitudinal central impunctate area bounded on each side by a row of 16 or 17 large equidistant punctures, with a narrow, irregular, impunctate area next to same almost as long as the pronotum; sides somewhat evenly punctured to lateral margin; surface with a feeble dactylographic pattern of wavy lines.
Elytra.—With suture slightly shorter than pronotum; each elytron about % as wide as sutural length; surface very densely and roughly punctured.
Abdomen.—Almost as densely but somewhat more finely punctured than elytra; acrocostal suture straight; pubescence fine, longitudinal throughout. Undersurface finely, densely punctured.
Male characters. —First 4 segments of anterior tarsus dilated. Apical margin of 6th sternite with an oval emargination about as deep as wide. Aedeagus most similar to that of C. luteipennis male, but with apex of median lobe more blunt and somewhat bulbous.
Female characters. —Anterior tarsus almost as broadly dilated as in male. Apical margin of 6th sternite entire.
Notes.—Adults of this species are smaller and darker than western specimens of Cafius bistriatus (Erichson). They differ from members of all other North American
198
Cafius species in that the ground sculpture of the head and pronotum consists of fine wavy lines in a dactylographic pattern. This condition is most apparent on the gula. In adults of most other North American species the gula is so densely reticulate that it has a granular appearance.
We have seen 2 specimens from western North America and 21 specimens from eastern North America.
Distribution. —This species was originally described from the West Indies. We have seen 1 male and 1 female from San Blas, Nayarit, Mexico, September 17-20, 1953, B. Malkin collector in the collection of the California Academy of Sciences. This is the first record of this species from the west coast of North America.
THE SPECIES OF CAFIUS OF EASTERN NORTH AMERICA
We have not been able to treat the species of Cafius of eastern North America (including the West Indies) as exhaustively as those of western North America. Type specimens of most of them have not been studied. However, dissections have been made of the genitalia of what we believe to be authentically identified specimens.
On the basis of our studies, we have decided that the European species Cafius sericeus Holme has not yet been validly recorded from North America. The species which has gone under that name should be called C. aguayoi Bierig. Cafius aguayoi was synon- ymized with C. sericeus by Blackwelder, 1943. We believe C. rufifrons Bierig to be a valid species, not a synonym of C. bistriatus (Erichson) as suggested by Blackwelder, 1943. Other changes may be necessary, but we lack material on which to base these decisions. These possibilities are discussed under the notes on some of the following species.
Key for identification of Cafius of eastern North America
Av Headeneddish= Drow c.2ts coche Cem te toe eee erase 1. C. rufifrons Bierig AA. Head black or piceous. Ba Groundsculpture of culajieranulose=s 244-0 ee ee 2. C. bistriatus (Erichson)
BB. Ground sculpture of gula fine wavy lines.
C. Ground sculpture of head and pronotum fine wavy lines ..3. C. caribeanus Bierig CC. Ground sculpture of head and pronotum finely granulose.
D. Larger species (length of head, pronotum and elytra 2.2-2.8mm)...............
Atlantic coastof the Wimitedistatess sae er i eee ee 4. C. aguayoi Bierig DD. Smaller species (length of head, pronotum and elytra 1.8-2.2 mm) .............. WES THINGS Saeco Riey Reem Se face eee ae erm ea Rona creme nero 5. C. subtilis Cameron
1. Cafius rufifrons Bierig Figs. 3C, 8G-H.
Cafius rufifrons Bierig, 1934, Revista Ent. 4:67-68; Koch, 1936, Publ. Mus. Ent. Pietro Rossi, 1:176, 187; Blackwelder, 1943, Bull. U.S. Nat. Mus. 182:438.
This species was synonymized with Cafius bistriatus (Erichson) by Blackwelder, 1943; but we believe it to be distinct. Adults differ from those of other east coast Cafius species in its reddish-brown head. Although it is otherwise similar to C. bistriatus, the aedeagus is not as abruptly narrowed towards the apex as in males of that species.
A single specimen in the United States National Museum is labeled ‘‘Miami, VI-36, A. Bierig Coll., Fla./USA, Paratype No. 52746 USNM.”’ This cannot be a paratype because the original description was in 1934, 2 years earlier than the specimen was collected.
We have examined 20 specimens.
199
2. Cafius bistriatus (Erichson) Figs. 3A, 5E, 8C-D, 10.
This species is recorded in this paper for the first time from the west coast of North America. Full citations, descriptions and notes are given in that section of this paper.
Considerable variation exists in the ground sculpture in specimens from the extremes of range in eastern North America. However, only minor differencs have been found in the male genitalia and these appear to intergrade between the extremes of range. Long series of specimens from Long Island Sound and from Chesapeake Bay consistently have the head and pronotum with dense reticulate ground sculpture; whereas, in specimens from the West Indies and western North America, those parts are weakly reticulate with occasional smooth polished areas. Some specimens from the southeastern United States are intermediate. We lack extensive material from the intermediate region. For the pres- ent, it appears best to leave the synonymy as given. If the 2 forms are determined to be separate species, the name C. bistriatus (Erichson) will apply to specimens from north- eastern United States and C. bilineatus (Erichson) to the southern and western form.
Most specimens from the West Indies and western North America were collected from open sandy beaches, whereas those from Long Island and Chesapeake Bay were found under sea lettuce (U/va) on the shores of protected waters.
3. Cafius caribeanus Bierig Figs. 3B, 8E-F.
This species is recorded in this paper for the first time from the west coast of Mexico. Full citations, description and notes are given in that section of this paper.
It has previously been known only from the West Indies. It is unusual in that the ground sculpture of the adult head and pronotum is in the form of fine wavy lines in a dactylographic pattern. In males of this species, the aedeagus is bulbous at the apex and the paramere is relatively longer than in males of other eastern species.
We have examined 21 specimens from the West Indies.
4. Cafius aguayoi Bierig Figs. 3D, 9A-B.
Cafius sericeus (Holme), Horn, 1884, Trans. Amer. Ent. Soc. 11:235, 238 (not Holme, 1837).
Cafius aguayoi Bierig, 1934, Revista Ent. 4:66; Koch, 1936, Publ. Mus. Ent. Pietro Rossi
e192:
This is a common species along the eastern seashore of the United States. It has been listed as Cafius sericeus Holme, a European species which is very similar in appearance. However, the male genitalia differ sufficiently for us to determine that they represent distinct species. The paramere is distinctly more slender than in males of the European C. sericeus Holme (Figs. 9E-F). Specimens of C. aguayoi Bierig appear not to differ from those of other east coast specimens, so we apply that name to this species. It is known only from the east coast of the United States.
We have seen 463 specimens.
5. Cafius subtilis Cameron Figs. 4, 9C-D.
Cafius subtilis Cameron, 1922, Ann. Mag. Nat. Hist., Ser. 9, 9:121; Blackwelder, 1943, Bull. U.S. Nat. Mus. 182:436.
Cafius sericeus var. subtilis (Cameron), Koch, 1936, Publ. Mus. Ent. Pietro Rossi, 1:192. The adults of this very small species are similar to those of Cafius aguayoi Bierig.
There seems to be a slight difference in the male genitalia, the paramere of the C. subtilis
200
males being relatively shorter than that of C. aguayoi males. Specimens seen are all from the West Indies. Blackwelder, 1943, treated this species as distinct from the species we call C. aguayoi. We feel that we have seen insufficient material to suggest any change. If the 2 species are ever synonymized, the name C. subtilis has precedence over C. aguayoi.
We have examined 23 specimens.
ACKNOWLEDGMENTS
We extend our thanks to the following people who have given us assistance: J.M. Campbell, J. Chilson, K. Cooper, H.S. Dybas, T. Erwin, D.H. Kavanaugh, V. Lee, A. Newton, V. Roth, E. Smith, P. Spanger and R. Wenzel.
LITERATURE CITED
Bierig, Alexander 1934. Neues aus der Staphyliniden-Gattung Cafius (Col.), nebst beschreibung neuer Arten aus Kuba und Nordamerika (8. Bietrag zur Ken- ntnis der Staphyliniden). Revista De Ento- mologia 4: 65-70, illus. Blackwelder, Richard Eliot 1943. Monograph of the West Indian beetles of the family Staphylinidae. United States Nation- al Museum. Bulletin No. 182: 1-658, illus. 1952. The generic names of the beetle family Staphylinidae with an essay on genotypy. United States National Museum. Bulletin No. 200: i-iv, 1-483. Cameron, Malcolm 1922. Descriptions of new species of Staphylinidae from the West Indies. Part II. Annals and Magazine of Natural History, series 9, 9: 113-128, 633-652. Casey, Thomas Lincoln 1885. New genera and species of Californian Col- eoptera. California Academy of Sciences. Bulletin 1: 285-336. Curtis, John 1829. British entomology; being illustrations and descriptions of genera of insects found in Great Britain and Ireland; containing col- oured figures from nature of the most rare and beautiful species and, in many instances, of the plants upon which they are found, (2nd edition), Vol. 1, Pls. 1-5, London. Dvorak, Rudolf 1957. A character useful in separating Cafius (sg. Bryonomus) seminitens Horn and canescens Makl. (Coleoptera: Staphylinidae). Entomo- logical News 68: 17-18, illus. Erichson, Wilhelm Ferdinand 1840. Genera et species staphylinorum insectorum coleoptorum familiae. (pt. 2) pp. 401-954: Berlin, F.H. Morin. Fall, Henry Clinton 1916. Three new Coleoptera from Washington State. Brooklyn Entomological Society. Bulletin 11: 13-14. Geminger, Max, and Edgar von Harold 1868. Catalogus coleopterorum hucusque descrip- torum synonymicus et systematicus. 2: 425-753, Munich.
Hatch, Melville Harrison
1957. Beetles of the Pacific Northwest. Part II. Staphyliniformia. University of Washington Publications in Biology i-x, 1-384, illus.
Horn, George Henry
1884. Synopsis of the Philonthi of Boreal North America. American Entomological Society. Transactions 11:177-244.
1894. The Coleoptera of Baja California. Califor- nia Academy of Science. Proceedings, Series 2, 4: 302-449, illus.
James, Gary, Ian Moore and E.F. Legner
1971. The larval and pupal stages of four species of Cafius (Coleoptera: Staphylinidae) with notes on their biology and ecology. San Diego Society of Natural History. Transac- tions 16; 279-289, illus.
Koch, Carl
1936. Wissenschaftliche Ergebnisse der entomol- ogischen Expedissionen seiner Durchlaucht des Flisten Alessandro C. Della Torre e Tasso nach Aegypten und die Halbinsel Sinae. XIII. Staphlinidae. Pubblicazioni del Museo Entomologico Pietro Rossi 1: 115-232.
LeConte, John Lawrence
1863. New species of North American Coleoptera, Part I. Smithsonian Miscellaneous Collec- tions VI, No. 167: 1-92.
1961. Letter from LeConte to Alexander Agassiz. Coleopterists Bulletin 15: 128.
Leech, Hugh Bosden, and lan Moore
1971. Nearctic records of flights of Cafius and some related beetles at the seashore (Coleop- tera: Staphylinidae and Hydrophilidae). Wassman Journal of Biology 29: 65-70, illus.
Maklin, Fredericke Guillelmo
1852. New species and notes in: C.G. Man- nerheim, Zweiter Nachtrag zur Kaefer- Fauna der Nord-Americanischen Laender des Russischen Reiches. Societe Imperiale des Naturalistes de Moscou. Bulletin 25(2): 283-372.
1853. In: C.G. Mannerheim, Dritter Nachtrag der Kaeffer-Fauna der Nord Amerikanischen Laender des Russischen Reiches. Societe Imperiale des Naturalistes de Moscou. Bulletin 26(3): 95-269.
Moore, Ian
1965. The genera of the Staphylininae of America North of Mexico (Coleoptera: Staphylin- idae). Coleopterists Bulletin 19: 97-103, illus.
1974. Cafius sulcicollis LeConte from the Gulf of California (Coleoptera: Staphylinidae). Col- eopterists Bulletin 28: 119.
1975. The larva of Cafius sulcicollis LeConte (Col- eoptera: Staphylinidae). Pan-Pacific Ento- mologist 51: 140-142, illus.
Moore, Ian, and E.F. Legner
1973. Speculation on the distribution of the southern California species of Cafius with a new record from the Salton Sea (Coleoptera: Staphylinidae). Pan-Pacific Entomoiogist 49: 279-280.
201
Orth, R.E., lan Moore and T.W. Fisher 1978. Year-round survey of Staphylinidae of a sandy beach in southern California (Col- eoptera). Wasmann Journal of Biology 35: 169-195, illus. Sharp, David 1874. The Staphylinidae of Japan. Entomological Society of London. Transactions 1874: 1-101.
Orth: Division of Biological Control, Department of Entomology, University of Califor- nia, Riverside, California 92521, USA. Moore: 7130 Orchard Street, Riverside, California
92504, USA.
202
FIGURE 1. (A) Cafius seminitens Horn. USA, California, Santa Barbara County, Refugio State Beach, 22 April 1976, R. Orth; (B) Cafius canescens (Maklin). USA, California, Santa Barbara County, Refugio State Beach, 22 April 1976, R. Orth; (C) Cafius opacus (LeConte). USA, California, Santa Barbara County, Refugio State Beach, 8 Nov. 1976, R. Orth; (D) Cafius femoralis (Maklin). USA, California, Mendocino County, Needle Rock, 6 Oct. 1974, D. Giuliani.
203
1.0mm
FIGURE 2. (A) Cafius lithocharinus (LeConte). USA, California, Santa Barbara County, Refugio State Beach, 18 May 1976, R. Orth; (B) Cafius luteipennis Horn. USA, California, Santa Barbara County, Refugio State Beach, 18 May 1976, R. Orth; (C) Cafius decipiens (LeConte). USA, California, San Diego, LeConte, Type 6290; (D) Cafius sulcicollis (LeConte). USA, California, Santa Barbara County, Refugio State Beach, 15 Sept. 1976, R. Orth.
204
FIGURE 3. (A) Cafius bistriatus (Erichson). MEXICO, Sonora, El Desemboque, 23 May 1974, Brown and Speith; (B) Cafius caribeanus Bierig. MEXICO, Nayarit, San Blas, 17-21 Sept. 1953, B. Malkin; (C) Cafius rufifrons Bierig. USA, Florida, Miami, June 1936, A. Bierig; (D) Cafius aguayoi Bierig. USA, Connecticut, Fairfield County, Westport, Sherwood Island State Park, 20 Aug. 1978, R. Orth family.
205
FiGurE 4. Cafius subtilis Cameron. CUBA, Provincia Habana, Playa Marianao, 1929, A. Bierig.
206
0.5mm
A B C D E
FiGuRE 5. Antennae of Cafius. (A) Cafius seminitens Horn; (B) Cafius canescens (Maklin); (C) Cafius opacus (LeConte); (D) Cafius femoralis (Maklin); (E) Cafius bistriatus (Erichson).
207
D i F
FIGURE 6. Aedeagi of Cafius. (A-C) Cafius seminitens Horn (USA, California, Santa Barbara County, Refugio State Beach, 22 April 1976, R. Orth); (A) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (B) lateral view of aedeagus; (C) lateral view of aedeagus with internal sac everted; (D, E) Cafius canescens (Maklin) (USA, California, Santa Barbara County, Refugio State Beach, 19 July 1976, R. Orth); (D) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (E) lateral view of aedeagus; - (F, G) Cafius opacus (LeConte) (USA, California, Santa Barbara County, Refugio State Beach, 19 July 1976, R. Orth); (F) ventral view of aedaegus and apical part of underside of paramere with sen- sory tubercles; (G) lateral view of aedeagus.
208
0.2mm
0.2mm
i F G i
FIGURE 7. Aedeagi of Cafius. (A, B) Cafius femoralis (Maklin) (USA, California, Mendocino County, Needle Rock, 6 Oct. 1974, D. Giuliani); (A) ventral view of aedeagus and apical part of underside of paramere with sen- sory tubercles; (B) lateral view of aedeagus; - (C, D) Cafius lithocharinus (LeConte) (USA, California, Santa Barbara County, Refugio State Beach, 18 May 1976, R. Orth); (C) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (D) lateral view of aedeagus; - (E, F) Cafius /uteipennis Horn (USA, California, Santa Barbara County, Refugio State Beach, 8 Sept. 1977, R. Orth); (E) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (F) lateral view of aedeagus; - (G, H) Cafius decipiens (LeConte) (USA, California, San Diego County, San Diego); (G) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (H) lateral view of aedeagus with internal sac everted.
209
0.2mm 0.2mm
i
0.2mm 0.2mm
E F G isl
FIGURE 8. Aedeagi of Cafius. (A, B) Cafius sulcicollis (LeConte) (USA, California, Santa Barbara County, Refugio State Beach, 14 Mar. 1977, R. Orth); (A) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (B) lateral view of aedeagus; - (C, D) Cafius bistriatus (Erichson) (MEXICO, Sonora, El] Desemboque, 23 May 1974, Brown and Speith); (C) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (D) lateral view of aedeagus; - (E, F) Cafius caribeanus Bierig (MEXICO, Nayarit, San Blas, 17-21 Sept. 1953, B. Malkin); (E) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (F) lateral view of aedeagus; - (G, H) Cafius rufifrons Bierig (CUBA, Playa Marianao, 8 Sept. 1929, A. Bierig); (G) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (H) lateral view of aedeagus.
210
FIGURE 9. Aedeagi of Cafius. (A, B) Cafius aguayoi Bierig (USA, Connecticut, Fairfield County, Norwalk, Calf Pasture Beach, 9 Aug. 1978, R. Orth family); (A) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (B) lateral view of aedeagus; - (C, D) Cafius subtilis Cameron (PUERTO RICO, San Juan, 28 Sept. 1935, R. Blackwelder); (C) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (D) lateral view of aedeagus; - (E, F) Cafius sericeus Holme (Galliamer, Reit- ter, A. Fenyes collection); (E) ventral view of aedeagus and apical part of underside of paramere with sensory tubercles; (F) lateral view of aedeagus.
2A
|
SALTON SEA
| \ ( | a a | Pod 28° __iCHIHUAHUA
AIG Mayas
FicuRE 10. Map showing west coast distribution of Cafius bistriatus (Erichson).
1c sone A is Pe = ie a
of pa > hart ve Pty! a } a wl
saa e
y _——- : at = a a a 2 ow es oo aa = a. et et =. 2) b= gis
ef ie) “ins ee a TI. a ~ 7 ve fe. ante ; wl 1 iy i rn | gel its rf 4 ey or vy, "= } i. e a V4 ae es Oe A4G eat ha a
TRANSACTIONS
e OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 14 pp. 213-216 14 November 1980
Dithyrocaris sp. (Phyllocarida) from the Allegheny Group of Ohio
Joan Matthews Schram
Abstract. Two phyllocarid carapaces and a phyllocarid tail collected from the Pennsylvanian Washingtonville Shale of Ohio are described and compared with known phyllocarid species. Not enough material was available to identify these specimens with a known species or to describe a new species, but the specimens are significant in documenting variation in the genus.
INTRODUCTION
Michael C. Hansen of the Ohio Division of Geological Survey called to my atten- tion two Dithyrocaris carapaces collected by Lloyd J. Millhorn in the Washingtonville Shale and given to Myron Sturgeon of Ohio University, Athens, Ohio. A further search of the collections at Ohio University yielded a tail collected by Sturgeon at a different locality within the same unit. These 3 specimens from the Pennsyl- vanian Washingtonville Shale are not preserved well enough to identify satisfac- torily with any known species or to describe as a new species. Although Dithyrocaris species are fairly common in Europe, there are so few in North America that any new material warrants description in the literature.
Dithyrocaris is fairly well known from the Devonian and Carboniferous of Europe. Jones and Woodward (1888-1899) wrote the definitive treatise incorporating all the European and North American specimens known at that time. Essentially no furthe work was done until Rolfe (1969) in the Treatise on Invertebrate Paleontology under took a preliminary revision of the various phyllocarid taxa. The result was the incor- poration of several former genera into one genus, Dithyrocaris. Rolfe stated a necessity for further revision, adding that features separating the genera of the Rhinocarididae may only be specific characters.
The known North American Carboniferous species include Dithyrocaris carbo- naria Meek and Worthen, 1870, and Rhacura? venosa Scudder, 1878, placed in Di- thyrocaris by Rolfe (1969). These species are based on specimens of tails, and neither is well known. Copeland (1967) described Dithyrocaris quinni from the Mississippian of Arkansas, based on carapaces and tails; and Schram and Horner (1978) described Dithyrocaris rolfei, an intact animal, from the Upper Mississippian of Montana.
Because the material from Ohio is fragmentary, and because the taxonomy of the group is confused, it seems better to designate these two carapaces and tail as Dithy- rocaris sp. rather than erect new species which would only serve to further confound the situation. More and better material and/or a revision of the entire genus might permit a specific designation some day.
OSU 33450 (Fig. 1, upper and lower right) and OSU 33451, two carapaces, are from Ohio University locality CAr-2 (Hoare et al., 1979, p. 66) in Rose Township, Carroll County, Ohio, in the James Bros. Mining Company strip mine. The tail, OSU 33452 (Fig. 1, left), is from Ohio University locality Cc-7 (Sturgeon and Hoare, 1968, p. 80), Center Township, Columbiana County, Ohio. Both localities are in the marine horizon of the Washingtonville Shale, Allegheny Group, Pennsylvanian System. Stur-
Ficure |. Dithyrocaris sp. Left. OSU 33452, the last abdominal segment showing the chevron line dec- oration, and telson and furca: Upper right. OSU 33450, carapace showing lateral carinae and part of the median dorsal plate: Lower right. Detail of posterodorsal corner of carapace OSU 33450, showing underlying segment with chevron line decoration, detail of juxtadorsal carina, and the ‘‘fish scale’’ pattern terrace lines of the carapace ornamentation.
geon and Hoare (1968) state that marine deposits of this age yield faunas often abundant in corals, bryozoans, fusilinids, arthropods, sponges, mollusks, and brachiopods. Al- though the Washingtonville Shale is heavily collected, Michael C. Hansen (personal communication) states that crustaceans of any sort are rare. These specimens are the only phyllocarids known to have been found.
The specimens are deposited in the Orton Museum of The Ohio State University, Columbus, Ohio with accession numbers OSU 33450, OSU 33451 and OSU 33452.
DISCUSSION
The tail OSU 33452 (Fig. 1, left) is similar to those of other Dithyrocaris species, with a telson about equal in length to the furca, and blade-shaped with a central median ridge. OSU 33452 resembles what is known of D. venosa (Scudder, 1878), though it is smaller than D. venosa. The tail (OSU 33452) does not seem to have many characters in common with D. carbonaria, D. rolfei or D. quinni, the other known American Carboniferous Dithyrocaris species with tails. Among the European Dithyrocaris species, D. colei and D. testudinea (Jones and Woodward, 1888-99) most resemble the tail and last segment of OSU 33452, including shape, the chevron decoration of the last segment, and a similar pattern of ridges on the telson and furca. The chevron lines on the last segment may relate the tail to the carapace OSU 33450, which appears to have the chevron lines on the segment underlying the carapace, but with the lack of further material, especially a whole specimen, relationship is uncertain.
The carapaces (OSU 33450, 33451) resemble the American Mississippian species, D. quinni (Copeland, 1967). However, they are not as strongly sclerotized in appear- ance, nor are the strong doublure edges preserved as in D. quinni. Dithyrocaris quinni has similar prominent lateral carinae. There is no close resemblance to D. rolfei, the other known Carboniferous American Dithyrocaris (Schram and Horner, 1978).
The unique ‘‘fish scale’’ terrace lines (Fig. 1, lower right) resemble in pattern that of the Devonian D. neptuni (Stumm and Chilman, 1969). Carapace decoration is a com- mon Dithyrocaris characteristic.
2S
Comparison of these specimens with European Dithyrocaris species shows a sim- ilarity to the median dorsal plates of D. paradoxides (Rolfe, 1969) and D. testudinea (Jones and Woodward, 1888-99). However, the carapace shape, the relative position of the lateral carinae and the decorative pattern seem to make these specimens unique and not directly comparable to any known American or European Dithyrocaris species. Other features used in analysis of Dithyrocaris species, such as a posterolateral spine, doublure or carapace edges, and most anterodorsal features, are missing in these two specimens.
SYSTEMATIC PALEONTOLOGY
Phyllocarida Packard, 1879 Archaeostraca Claus, 1888 Rhinocarina Clarke in Zittel, 1900 Rhinocarididae Hall and Clarke, 1888 Dithyrocaris Clarke in Hall and Clarke, 1888 Dithyrocaris sp.
Fig. |
Material.—OSU 33450, OSU 33451, OSU 33452.
Remarks.—Specimen OSU 33452 (Fig. 1, left) is the last abdominal segment and a nearly complete telson with furca. The fossil is in black shale and consists of some calcite remains as well as partial impression in the shale. The fossil is presumably preserved ventrally with the furcal rami lying over the telson. The last segment is ~5.1 mm in length while the telson is 11.4 mm. The furca measure ~11.0 mm and 11.8 mm respectively. The measurements are approximate due to the crushed and somewhat distorted state of the fossil. The telson is judged to have been about equal to the furca in length. The telson is narrow and blade-shaped with a dorsal ridge down the center, viewed as a depression in the fossil. The telson has straight sides with no convexity and ends in a sharp point. No spines or spinules are present. The furcal rami are also long and narrow, with no convexity in their shape. There is a center ridge with two lateral, less distinct ridges to each side, which curve toward the center ridge at the head of the ramus and disappear toward the narrow tip. These may reflect depressions dorsally. There are no spines or spinules apparent on the furca. The last abdominal segment has the chevron decoration common in Dithyrocaris species. The chevrons point posteriorly.
Specimens OSU 33450 (Fig. 1, right upper and right lower) and OSU 33451 are incomplete carapaces in black shale and are partially replaced with calcite. Both are somewhat twisted, OSU 33451 more so, and are apparently flattened laterally. None of the carapace edges, posterior, anterior, or lateral, are complete. There is a possible remnant of doublure edging laterally on OSU 33451, but it seems broken and displaced. The dorsal length measured from the anterior tip of the carapace to the posterior edge is 25.2 mm on OSU 33450 and 24.5 mm on OSU 33451. OSU 33450 has remnants on one side anteriorly of a short cephalic carina running just above the anterior portion of the mesolateral carina and ending just below the juxtadorsal carina. Anteriorly it ends at the broken edge of the carapace. The mesolateral carina runs from anterior edge to posterior edge on both specimens. The mesolateral carina is a fold line and on both specimens there are remnants of blunt very short spinules pointing posteriorly on both specimens but they are for the most part missing and broken. There are apparently pitted areas running along both sides of the mesolateral carina, more apparent on OSU 33450 than on OSU 33451. The pits are tiny and perhaps had a sensory function. A strong juxtadorsal carina begins just above the end of the cephalic carina and ends just before the posterior edge of the carapace. This carina lies near the median dorsal plate dorsally. The carina is composed of raised knobs or blunt spinules joined at their base and directed in a latero-posterior direction, similar to the spinules present on the lateral carina mentioned above. The juxtadorsal spinules are more pronounced anteriorly than posteriorly along the carina. Both specimens have a median dorsal plate or the remains
216
of one, which appears solid and separate from the carapace. The dorsal plate is in appearance composed of imbricating posteriorly pointed blunt chevrons. Where the dorsal plate appears to end on OSU 33450_near the anterior end of the carapace 2 rows of blunt spinules arise, point posterolaterally, and form 2 ridges which diverge slightly, run parallel to each other across the carapace and disappear at the broken anterior edge. The area between these ridges was probably the area of the rostral plate.
OSU 33450 and OSU 33451 are decorated with a ‘fish scale’’ or “‘terrace’’ pattern, which anterodorsally is composed of many fine wavy lines which become more like fish scales posterolaterally. These terraces end in an ordered fashion on either side of the juxtadorsal carina (OSU 33450, Fig. 1, lower right). OSU 33450 (Fig. 1, upper and lower right) is broken posterodorsally revealing an underlying segment with a pattern of straight lines aligned diagonally and posteriorly. This indicates that the segment underlying the carapace at this point had the chevron line decoration common in Di- thyrocaris species and which I have seen in the pre-telson segment of the tail (OSU 33452). The ‘‘fish scale’’ pattern continues to the ventral broken edge of the carapace. Edges of the carapaces are not preserved. However, OSU 33451 has tiny fragmentary pieces of what may have been doublure but which is broken and displaced.
There does not appear to be a posteroventral spine, but as the posterior carapace edges are missing, absence or presence is uncertain. OSU 33450 has anteroventrally two large prominent protuberances which may be remains of large mandibles.
ACKNOWLEDGMENTS
Thanks must be extended to the following people: Michael C. Hansen for bringing these specimens to my attention, Thomas A. Demere for taking the photographs, and Frederick R. Schram for criticism. Finally, special thanks to Martin D. Burkenroad for the grant which supported this work.
LITERATURE CITED
Copeland, M. J. 1967. A new species of Dithy- rocaris (Phyllocarida) from the Imo Forma- tion, Upper Mississippian of Arkansas. Jour- nal of Paleontology 41(5): 1195-1196.
Hall, J., and J. M. Clarke. 1888. Trilobites and other Crustacea of the Oriskany, Upper Held- erberg, Hamilton, Portage, Chemung and Catskill Groups. Natural History New York, Paleontology, Vol. 7.
Hoare, R. D., M. T. Sturgeon, and E. A. Kindt. 1979. Pennsylvanian marine Bivalvia and Rostroconchia of Ohio. Ohio Geological Sur- vey Bulletin 67:1-77.
Jones, T. R., and H. Woodward. 1888-1899. A monograph of the British Paleozoic Phyllopoda (Phyllocarida, Packard). Palaeontographical Society Monograph, parts I-IV: 1-211.
Meek, F. B., and A. H. Worthen. 1870. Descrip- tions of new species and genera of fossils from the Paleozoic rocks of the western states. Pro- ceedings of the Academy of Natural Sciences of Philadelphia 22:22-56.
Rolfe, W. D. 1. 1969. Phyllocarida, p. R296—-R331. In R. C. Moore (ed.), Treatise on Invertebrate Paleontology, Pt. R, Arthropoda 4(1), Geolog- ical Society of America and University of Kansas Press, Lawrence.
Schram, F. R., and J. Horner. 1978. Crustacea of the Mississippian Bear Gulch Limestone of central Montana. Journal of Paleontology 52(2):394—406.
Scudder, S. H. 1878. Rhachura, a new genus of fossil Crustacea. Boston Society of Natural History Proceedings 19:296—-300.
Stumm, E. C., and R. B. Chilman. 1969. Phyllo- carid crustaceans from the Middle Devonian Silica Shale of northwestern Ohio and south- eastern Michigan. Contributions from the Mu- seum of Paleontology, The University of Michigan 23(3):53-71.
Sturgeon, M. T., and R. D. Hoare. 1968. Penn- sylvanian brachiopods of Ohio. Ohio Geolog- ical Survey Bulletin 63:1-95.
Department of Geology, San Diego Natural History Museum, P.O. Box 1390, San
Diego, California 92112 USA.
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 15 pp. 217-226 14 November 1980
A late Pleistocene molluscan fauna from San Dieguito Valley, San Diego County, California
Thomas A. Demere
Abstract. A molluscan fauna, totaling 26 species of pelecypods and 21 species of gastropods, is described from a late Pleistocene deposit in San Dieguito Valley, San Diego County, California. The fauna lived ~250 000 years B.P. along the north shore of a protected marine embayment, and contrasts with other much larger fossil assemblages from the San Diego Pleistocene in its preservation of a community death assemblage. Infaunal, suspension-feeding pelecypods requiring clean to muddy sand substrates represent the dominant trophic group in the fauna. Minor postmortem transport deposited these and other trophic groups (e.g., infaunal, deposit-feeding pelecypods, epifaunal deposit-feeding gastropods and epifaunal predaceous gastropods) as a shell lag which supported a trophic group of epifaunal, suspension-feeding pelecypods (oysters and jingle shells). Subsequent clastic deposition apparently preserved this shell lag habitat in situ. Five southern extralimital species suggest that water temperatures in this Pleistocene marine embayment were somewhat warmer than today. The presence of Pinna cf. P. corteziana Durham is a record for this genus and species in the late Pleistocene of southern California. In addition, 2 species, Megapitaria squalida (Sowerby) and Tellina simulans C. B. Adams, are new to the late Pleistocene of San Diego County.
INTRODUCTION
Upper Pleistocene marine deposits in coastal San Diego County are often richly fossiliferous and occur as patchy and thin basal veneers on elevated marine terraces and around the margins of sheltered embayment and drowned river mouths. Molluscan assemblages in these deposits have been described by numerous authors (see refer- ences in Kern, 1971, 1977).
One of the early pioneers in the Pleistocene paleontology of San Diego County was Frank Stephens who in 1929 published a paper entitled, “‘Notes on the marine Pleistocene deposits of San Diego County, California.’’ This paper summarized all of the then known localities of Pleistocene deposits and provided a brief faunal listing from each. In recent years several of these localities have been re-examined (Emerson and Addicott, 1953; Valentine, 1960; Kern et al., 1971) and as a consequence their faunal and paleoenvironmental parameters are now more precisely known. As a con- tinuation of this process of re-examination the present author has recollected and studied a rather unique locality in San Dieguito Valley near the city of Del Mar in San Diego County, California (Fig. 1).
Stephens (1929, p. 255) described SDSNH (San Diego Society of Natural History) locality 0069 as follows: ‘‘In its eastern part, the shells are weathered out and scattered over the hillside, with no stratum discernible. In the western part, in a small gulch, is a stratum of lime-cemented sandstone containing fossil shells .... Stephens also included a small list of the more common molluscan species from this locality: ““Aletes squamigerus, Chione succincta, Chione undatella, Diplodonta sericata, Diplodonta subquadrata, Ostrea lurida, Phacoides nuttallii, Pecten aequisulcatus, Pinna sp., Ta- gelus californianus.”
In 1976, grading operations for a shopping center cut into the ‘western part”’ of SDSNH locality 0069, creating new exposures of unweathered Pleistocene sediments. Because Stephens’ original locality was actually a composite of 2 localities (i.e., his
‘
ZA A egies
BO Tr SO).
Ficure 1. Map of the San Dieguito Valley area showing the location of SDSNH locality 2904. Inferred late Pleistocene land areas are indicated by diagonal lines.
‘eastern’? and ‘‘western’’ parts), this recent cut was assigned to a new locality (SDSNH locality 2904). The stratigraphic section exposed in this cut consists of ~6m of poorly consolidated marine sands that unconformably truncate siltstones and sand- stones of the middle Eocene Delmar Formation (Fig. 2). The Pleistocene sediments are generally massive with the exception of a highly fossiliferous, 40-cm-thick bed that extends across the outcrop with a southerly dip of 5°. This bed is probably Stephens’ ‘‘lime-cemented sandstone” as it is quite well indurated due to the high concentration of fossil shells. Lithologically this bed is composed of yellow-tan, poorly sorted, sub- angular, coarse- to fine-grained sand with occasional mudstone and ‘‘Poway’’-type cobbles. Shells within the bed are randomly oriented except for large pen shells (Pinna) that lie with their long axes parallel to the bedding. Fossil preservation is excellent as all molluscan species retain their original shell material. The occurrence of fragile shells (Bulla, Tagelus, Leptopecten and Pinna) together with commonly paired valves of Chione californiensis (some with the ligament preserved) and Felaniella sericata sug- gests only a minor amount of postmortem shell transport.
Fossils were collected during April 1976 from a single 0.5 m® excavation. In all, ~100 kg of fossils and matrix were removed and examined. The large pen shells were
Ficure 2. SDSNH locality 2904 viewed from the east. The irregular dashed line represents the uncon- formable contact between the Pleistocene marine sands and the Eocene marine sediments. The vertical scale in the lower right corner represents | m.
removed from the outcrop individually whereas all remaining fossils were sorted from the bulk matrix.
In addition to the collection made from SDSNH locality 2904 several smaller collections obtained from near this locality by other workers were also examined. These are: SDSNH locality 0069; SDSU (San Diego State University) locality 636; and LACMIP (Natural History Museum of Los Angeles County, Invertebrate Paleontology Section) locality 4585.
DISCUSSION
Age
Biostratigraphic dating of California marine Pleistocene deposits 1s inherently imprecise due to the modern aspect of the fossil faunas (e.g., 98% of the San Dieguito Valley fauna is represented by extant species). The variety of preserved facies in these deposits (e.g., exposed rocky shores, protected sand flats, offshore mud bottoms), each with its own associated fauna, also serves to limit biostrati- graphic correlations. Y
Historically, the San Diego Pleistocene molluscan faunas have been assigned to the Bay Point Formation of Hertlein and Grant (1939, p. 71-72) which they and sub- sequent workers (Addicott and Emerson, 1959, p. 24) correlated with the regional type late Pleistocene Palos Verdes Sand of Woodring et al. (1946). However, recent work by Kern (1977), Masters and Bada (1977), Wehmiller et al. (1977), and Karrow and Bada (1980) has documented the existence of at least 3 temporarily distinct late Pleis- tocene marine terraces in the San Diego area. In terms of absolute ages they have distinguished terraces at 80-85 000 years B.P., 120-130 000 years B.P. and 250 000 (+50000) years B.P. Preliminary work on Chione shells from San Dieguito Valley (SDSU locality 636) places this deposit within the 250 000 (+50 000) years B.P. range (J. P. Kern, personal communication)
Fauna Forty-seven species of mollusks (26 pelecypods and 21 gastropods), one species of foraminifer, and unidentified Crustacea (Decopoda and Ostracoda) were recovered
220
“oe
TABLE 1. Checklist of fossils from SDSNH localities 2904 and 0069, SDSU locality 636, and LACMIP locality 4585. Counts were only made for fossils from loc. 2904 and are based on 2 hinges per pelecypod specimen and | aperture per gastropod specimen. N = number of specimens per species; % = percent abundance; x = presence (without counts).
Localities 2904 0069 636 4585 Taxa N % Mollusca Pelecypoda Anomia peruviana Orbigny, 1846 53 3.0 Xx Xx x Argopecten aequisulcatus (Carpenter, 1864) 26 1.4 X X Chama pellucida Broderip, 1835 X Chione californiensis (Broderip, 1835) 297 16.6 Ki X Corbula luteola Carpenter, 1864 D, 51 Xx Xx Cryptomya californica (Conrad, 1837) 16 38) X Xx Diplodonta subquadrata (Carpenter, 1856) 18 1.0 X Donax californicus (Conrad, 1837) I sll Donax gouldii Dall, 1921 4 sf Xx Felaniella sericata (Reeve, 1850) 379 21.1 x x Laevicardium substriatum (Conrad, 1837) 32 1.8 X x Leptopecten latiauratus (Conrad, 1837) 32 1.8 x Lucina approximata (Dall, 1901) 297 16.6 X X Lucinisca nuttalli (Conrad, 1837) iS 4.2 Xx Xx Macoma nasuta (Conrad, 1837) 5) 33} Megapitaria squalida (Sowerby, 1835) 28 1.6 Xx Nemocardium centrifilosum (Carpenter, 1864) X Ostrea lurida Carpenter, 1864 66 Bi X X xX Pinna cf. P. corteziana Durham, 1950 12 od) x X Pitar newcombianus (Gabb, 1865) 12 od! Xx Xx Protothaca staminea (Conrad, 1837) 2 a Psammotreta viridotincta (Carpenter, 1856) 5 3 x Raeta undulata (Gould, 1851) 1 1 Septifer bifurcatus (Conrad, 1837) D, sil Tagelus californianus (Conrad, 1837) 4] 3} X x Tellina meropsis Dall, 1900 68 3.8 X x Tellina simulans C. B. Adams, 1852 5) 3 Trachycardium quadragenarium (Conrad, 1837) 1 sl Gastropoda
Acteocina culcitella (Gould, 1853) 5) 3.1 X Acteocina inculta (Gould, 1855) X Alabina diegensis Bartsch, 1911 3} yt Alabina tenuisculpta Carpenter, 1864 12 si X Alabina tenuisculpta phalacra Bartsch, 1911 2 1 Xx Anachis coronata (Sowerby, 1832) 85 4.7 Astraea undosa (Wood, 1828) 6 pS) Xx Bulla gouldiana Pilsbry, 1893 7 4 Caecum crebricinatum (Carpenter, 1864) 3} 2) X Conus californicus Reeve, 1844 8 4 X Crepidula onyx Sowerby, 1824 1 al Crepipatella lingulata (Gould, 1846) 4 2 X Hipponix antiquatus (Linnaeus, 1767) 1 oll
Littorina scutulata Gould, 1849 x
Melampus olivaceus Carpenter, 1857 I ml X Nassarius tegula (Reeve, 1853) 109 6.1 x x Neverita reclusiana (Deshayes, 1839) 2 sl Notoacmea insessa (Hinds, 1842) 2 al Odostomia cf. O. fetella Dall & Bartsch, 1909 2 ail Odostomia cf. O. diegensis Dall & Bartsch, 1903 X Pyramidella adamsi Carpenter, 1864 12 oH Xx Rissoina californica Bartsch, 1915 l l Serpulorbis squamigerus (Carpenter, 1857) X X Triphora pedroana Bartsch, 1907 l al
Tryonia cf. T. imitator (Pilsbry, 1899) 5 ne) x
7d, TABLE |. Continued. Localities 2094 0069 636 4585 Taxa N NG Foraminifera Ammonia beccarii (Linnaeus, 1758) Xx Crustacea
Ostracoda (sp. indeterminate) X Decapoda (sp. indeterminate) X
from SDSNH locality 2904. In addition, examination of supplementary collections has added 6 species of mollusks (2 pelecypods and 4 gastropods) to this fauna. These are all listed in Table | along with abundance data.
Pelecypods dominate the fauna both in numbers of species and in numbers of individuals. The 3 most abundant species are Felaniella sericata (21% of specimens counted), Chione californiensis (16%), and Lucina approximata (16%).
The San Dieguito Valley fauna is small in terms of number of species when com- pared to other late Pleistocene molluscan assemblages from the San Diego area. For example, a collection from the old Spanish Bight locality on North Island (SDSNH locality 0056) contains more than 190 molluscan species. This high diversity is related to a mixing of faunal elements from several different marine habitats (i.e., a mixed death assemblage). The significance of the lower diversity, San Dieguito Valley fauna, lies in its apparent preservation of a more confined ecological unit (i.e., a community death assemblage).
Perhaps the most unusual taxonomic aspect of the fauna is the occurrence of the large pen shell, Pinna cf. P. corteziana Durham, 1950 (Fig. 3a, b). This extinct species was originally described from Pleistocene deposits on Isla Coronados in the Gulf of California. Pinna corteziana Durham differs from its closest living relative Pinna ru- gosa Sowerby, 1835, by its smaller apical angle and more nearly squared cross section (Durham, 1950, p. 57). In addition, the anterior muscle scar is much larger on P. corteziana than on P. rugosa. The San Dieguito Valley specimens possess the larger muscle scars and show a tendency towards squared cross sections, but the apical angles are greater than noted by Durham. His specimens measured 22°—23°, as opposed to a range of 22°-33° (¢ = 26°) for the specimens from San Dieguito Valley. Because of the greater apical angle range, these specimens are only tentatively referred to Pinna corteziana Durham.
Stephens’ (1929, p. 255) record of Pinna sp. from San Dieguito Valley (SDSNH locality 0069) was the only previous record of a fossil pinnid in the late Pleistocene of southern California. An examination of his original specimens shows them to be iden- tical to those from SDSNH locality 2904. In addition, 2 other species, Megapitaria squalida and Tellina simulans, represent new records for the San Diego Pleistocene.
Paleoenvironment
Paleoenvironmental reconstruction of the San Dieguito Valley deposit is enhanced by the essentially modern aspect of the molluscan fauna, the preservation of the pa- leogeographic setting, the excellent preservation of the fossils, and the apparently low degree of postmortem shell transport.
The fauna is representative of protected conditions with such species as Chione californiensis, Donax californicus, Tagelus californianus, and Nassarius tegula re- stricted today to coastal marine embayments (i.e., either bays, lagoons or estuaries) (Ricketts and Calvin, 1968; Warme, 1971; Coan, 1971, 1973b, 1973c; McLean, 1978). Except for the occurrence of Donax gouldii there is a noticeable lack of exposed coast
NO tN nN
Ficure 3. A, B. Pinna cf. P. corteziana Durham. SDSNH 04387. A, interior left valve, .4x; B, exterior same valve, .4x. C, D. Megapitaria squalida (Sowerby). SDSNH 04388. C, interior left valve, 2.3; D, exterior right valve, 2x.
i) i) Ww
Ficure 4. A, B. Psammotreta viridotincta (Carpenter). SDSNH 04389. A, interior left valve, 2x; B, exterior right valve, 2x. C, D. Diplodonta subquadrata (Carpenter). SDSNH 04390. C, interior right valve, 2x: D, exterior left valve, 2x. E, F. Tellina simulans C.B. Adams. SDSNH 04391. E, interior left valve, 2x; F, exterior right valve, 2x. G, Anachis coronata (Sowerby). SDSNH 04392. G, apertural view, 3x.
224
forms. Kern (1971, p. 815) pointed out that this species could easily be transported from the open coast into protected embayments. This agrees with the postulated pa- leogeographic setting in which an interglacial high sea stand flooded San Dieguito Valley creating a marine embayment. The inferred shoreline (Fig. 1) suggests that SDSNH locality 2904 on the northern shore of this embayment was exposed to >2 km of open water. Salinities within this portion of the embayment were probably normal marine as indicated by the majority of the faunal elements. Two species, Tryonia ck T. imitator and Melampus olivaceus, however, require hyposaline conditions, but it is likely that these taxa are allochthonous elements of the fauna derived from a more inland region of the embayment. Kern (1971, p. 817-819) described a Pleistocene es- tuarine fauna from nearby Carmel Valley which was characterized by stunted mollus- can individuals and abundant specimens of Tryonia. He concluded that his deposit accumulated under hyposaline conditions. There is no indication of this hyposaline- induced stunting in the San Dieguito Valley fauna, and it is probable that Kern’s locality occupied a more back bay position within the late Pleistocene Carmel Valley embayment.
Bathymetric ranges suggest that the fauna inhabited lower intertidal to adlittoral depths (0 to 10 m), with the majority of the abundant species being derived from the shallower regions of this zone (e.g., Nassarius tegula, Tagelus californianus and Chione californiensis). Pitar newcombianus and Raeta undulata occur in deeper water today but are sometimes washed ashore (Abbott, 1974; McLean, 1978). Both species are rare at SDSNH locality 2904.
The presence of 6 southern extralimital species (i.e., those species that now range only south of their fossil occurrence) suggest that water temperatures were probably warmer during deposition of the San Dieguito Valley fauna than today. These species and their present northern range end points are: Diplondonta subquadrata (San Ignacio Lagoon, Baja California, Mexico); Megapitaria squalida (Scammons Lagoon, Baja California, Mexico); Psammotreta viridotincta (Gulf of California); Tellina simulans (Scammons Lagoon, Baja California, Mexico); and Anachis coronata (Baja California, Mexico) (see Figs. 3 and 4). Pinna cf. P. corteziana, an extinct species, is most closely related to P. rugosa, which in the Holocene does not occur north of southern Baja California, Mexico (Keen, 1971, p. 75). The remainder of the fauna has living repre- sentatives that include San Diego within their zoogeographic ranges. There are no northern extralimital species.
As regards substrate preference, the fauna is dominated by species that live today in clean to muddy sand (e.g., Chione californiensis, Cryptomya californica, Felaniella sericata, Lucina approximata, Lucinisca nuttalli, Megapitaria squalida, Psammotreta viridotincta, Tagelus californianus and Tellina meropsis). A minor element of a detri- tus-rich mud substrate is indicated by the presence of Macoma nasuta. Notoacmea insessa is species-specific in its association with the brown alga Egregia (Ricketts and Calvin, 1968, p. 130) implying the presence of this floral element. The common occur- rence of Anomia peruviana and Ostrea lurida suggest the presence of firm substrates (i.e., rocks or shells). Interestingly several paired valves of these two species were observed still attached (life position) to slightly broken pen shells. This relationship together with the nearly coquina-like appearance of the deposit in outcrop suggests that the majority of the faunal elements accumulated as a shell lag which then served as a suitable substrate for the oysters and jingle shells. Subsequent clastic deposition essentially preserved this shell lag in situ.
Paleoecology
Autecological data obtained from numerous sources (Abbott, 1974; Coan, 1971, 1973a, 1973b, 1973c; Grant and Gale, 1931; Keen, 1971; McLean, 1978; Morris, 1966; Oldroyd, 1927; Ricketts and Calvin, 1968; Stanley, 1970; and Warme, 1971) allow some conclusions to be drawn concerning the paleoecology of the San Dieguito Valley fauna.
Infaunal, suspension-feeding pelecypods, characterized by Chione californiensis,
nN nN ‘n
Megapitaria squalida and Tagelus californianus, are the dominant trophic group in the fossil assemblage. Epifaunal, suspension-feeding pelecypods including byssally at- tached forms (Anomia peruviana) as well as cemented forms (Ostrea lurida) represent the next most dominant trophic group. An infaunal, deposit-feeding trophic group Is represented by Macoma nasuta. Gastropods in the fossil fauna have herbivorous rep- resentatives such as the epifaunal, deposit feeders Notoacmea insessa and Astrea undosa but are dominated by first order, epifaunal predators (Anachis coronata and Neverita reclusiana). Also represented is a second order predator (Conus californicus) and several ectoparasites (Odostomia cf. O. fetella and Pyramidella adamsi). The most abundant gastropod, Nassarius tegula, is both a scavenger and passive predator.
This fossil assemblage with 75% of its individuals as infaunal detritus feeders (both suspension and deposit) and the remaining 25% divided among epifaunal deposit feed- ers, active predators, scavengers and ectoparasites possibly functioned as a biocoe- nosis. There are postmortem immigrants but their occurrence is rare. The various substrates indicated by the fauna appear to represent microhabitats (e.g., sand flats, mud flats, shell lag) within a lower intertidal to adlittoral, protected level bottom, marine embayment biotope.
As discussed earlier shell contributions from these various microhabitats were apparently deposited together to form a shell lag microhabitat which supported pop- ulations of Anomia and Ostrea.
LOCALITY DESCRIPTION
SDSNH locality 2904.—Pleistocene. East-facing artificial cut on west end of Flow- er Hill Shopping Center near the northeast corner of the intersection of U.S. Interstate Highway 5 and Via de la Valle and east of the city of Del Mar, San Diego County, California. Lithology is a yellow-tan, poorly sorted, subangular, coarse- to fine-grained, moderately indurated, fossiliferous sand. Elevation ~20 m above sea level. Latitude 32°58'57" N; longitude 117°15'6” W. NE 44, SW 4%, Section 1, T14S, R4W (U.S. Geo- logical Survey 7.5 minute Del Mar, California, quadrangle, 1967 edition). Collectors Toby and Tom Demere, April 1976.
ACKNOWLEDGMENTS
I thank Frederick R. Schram, Curator of Paleontology, San Diego Natural History Museum (SDNHM), for guidance and invaluable assistance in completing this manu- script. Hans Bertsch, Tony D’ Attilio, Joyce Gemmell, Carol Hertz and Barbara Myers, Department of Marine Invertebrates, SDNHM, provided many fruitful discussions on molluscan ecology and taxonomy. I especially thank Toby and Deanne Deméere for their assistance in field work and manuscript preparation. William K. Emerson, Amer- ican Museum of Natural History, and George L. Kennedy, U.S. Geological Survey, Menlo Park, critically reviewed the manuscript.
LITERATURE CITED
Abbott, R. T. 1974. American seashells. Second edition, Van Nostrand Reinhold Company, New York, New York. 663 p.
Addicott, W. O., and W. K. Emerson. 1959. Late Pleistocene invertebrates from Punta Cabras, Baja California, Mexico. American Museum Novitates 1925: 1-33.
Coan, E. V. 1971. The northwest American Tellin- idae. Veliger 14 (supplement): 1-63.
Coan, E. V. 1973a. The northwest American Se- melidae. Veliger 15:314—-329.
Coan, E. V. 1973b. The northwest American Psammobiidae. Veliger 16:40—57.
Coan, E. V. 1973c. The northwest American Don- acidae. Veliger 16:130-139.
Durham, J. W. 1950. 1940 E. W. Scripps cruise to the Gulf of California. Part I]. Megascopic pa- leontology and marine stratigraphy. Geologi- cal Society of America, Memoir 43:1—216.
Emerson, W. K., and W. O. Addicott. 1953. A Pleistocene invertebrate fauna from the south- west corner of San Diego County, California. San Diego Society of Natural History, Trans- actions 11:429—444.
Grant, U. S., IV, and H. R. Gale. 1931. Catalogue of the marine Pliocene and Pleistocene Mol- lusca of California and adjacent regions. San Diego Society of Natural History, Memoir 1:1-1036.
Hertlein, L. G., and U. S. Grant, IV. 1939. Geol-
226
ogy and oil possibilities of southwestern San Diego County. California Journal of Mines and Geology 35:57-78.
Karrow, P. F., and J. L. Bada. 1980. Amino acid racemization dating of Quaternary raised ma- rine terraces in San Diego County, California. Geology 8:200-204.
Keen, A. M. 1971. Sea shells of tropical west America, marine mollusks from Baja Califor- nia to Peru. Second edition, Stanford Univer- sity Press, Stanford, California. 1064 p.
Kern, J. P. 1971. Paleoenvironmental analysis of a late Pleistocene estuary in southern Califor- nia. Journal of Paleontology 45:810-823.
Kern, J. P. 1977. Origin and history of upper Pleis- tocene marine terraces, San Diego, California. Geological Society of America Bulletin 88: 1553-1566.
Kern, J. P., T. E. Stump, and R. J. Dowlen. 1971. An upper Pleistocene marine fauna from Mis- sion Bay, San Diego, California. San Diego Society of Natural History, Transactions 16:329-338.
Masters, P. M., and J. L. Bada. 1977. Racemiza- tion of isoleucine in fossil molluscs from In- dian middens and interglacial terraces in southern California. Earth and Planetary Sci- ence Letters 37:173-183.
McLean, J. H. 1978. Marine shells of southern California. Second edition, Natural History Museum of Los Angeles County, Science Se- ries 24, Zoology 11:1—104.
Morris, P. A. 1966. A field guide to shells of the Pacific Coast and Hawaii. Second edition, Houghton Mifflin Company, Boston, Massa- chusetts. 297 p.
Oldroyd, I. S. 1927. The marine shells of the west coast of North America. Stanford University Publications in Geological Sciences 2(1-3): 941 p.
Ricketts, E. F., and J. Calvin. 1968. Between Pa- cific tides. Fourth edition, Stanford University Press, Stanford, California. 614 p.
Stanley, S. M. 1970. Relation of shell form to life habits of the Bivalvia (Mollusca). Geological Society of America, Memoir 125:1—296.
Stephens, F. 1929. Notes on the marine Pleisto- cene of San Diego County, California. San Diego Society of Natural History, Transac- tions 5:245-256.
Valentine, J. W. 1960. Habitats and sources of Pleistocene mollusks at Torrey Pines Park, California. Ecology 41:161-165.
Warme, J. E. 1971. Paleoecological aspects of a modern coastal lagoon. University of Califor- nia Publications in Geological Sciences 87:1- BIR
Wehmiller, J. F., K. R. Lajoie, K. A. Kvenvolden, E. Petersen, D. F. Belknap, G. L. Kennedy, W. O. Addicott, J. G. Vedder, and R. W. Wright. 1977. Correlation and chronology of Pacific Coast marine terrace deposits of con- tinental United States by fossil amino acid stereochemistry — technique evaluation, rela- tive ages, kinetic model ages and geologic im- plications. United States Geological Survey, Open-File Report 77-680: 1-191.
Woodring, W. P., M. N. Bramlette, and W. S. W. Kew. 1946. Geology and paleontology of Palos Verdes Hills, California. United States Geo- logical Survey, Professional Paper 207:1—14S.
Department of Geology, San Diego Natural History Museum, P.O. Box 1390, San
Diego, California 92112 USA.
:
= i mre Ny, Ty <i _ Z eae
>
i
> y Ll _ : ae _
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 16 pp. 227-250 7 July 1981
The genera of the Nannoniscidae (Isopoda, Asellota)
Joseph F. Siebenaller and Robert R. Hessler
Abstract. Four new genera of the deep-sea asellote isopod family Nannoniscidae Hansen are described. Two new species of Exiliniscus, new genus, are described, E. clipeatus and E. aculeatus. Nannoniscus hanseni Just is transferred to Exiliniscus. Nanncniscus crassipes Hansen is transferred to Rapaniscus, new genus; Rapaniscus dewdneyi, new species, is described. Nannoniscus tenellus Birstein is transferred to Panetela, new genus; Panetela wolffi, new species, is described. Nannoniscus armatus Hansen is referred to Regabellator, new genus; Regabellator profugus, new species, is de- scribed. The bathymetric ranges of the new genera are: Exiliniscus, 80-5223 m; Rapaniscus, 220-2934 m; Panetela, 770-5495 m; Regabellator, 1964-4680 m. The other 6 nannoniscid genera are reviewed and illustrated. Two new species of Nannoniscus Sars are described, N. intermedius and N. teres. A key to the family and a list of species are given. These new descriptions are based on benthic samples taken at 74 stations in the North and South Atlantic Ocean, encompassing a depth range of 508-5223 m.
INTRODUCTION
The family Nannoniscidae (Isopoda, Asellota) encompasses a broad range of di- verse morphologies. Recently, Siebenaller and Hessler (1977) have redefined the family to accommodate this diversity. The most useful features in distinguishing a nannoniscid are the bulbous fifth article of antenna I and the medial fusion dorsally of pereonites 6 and 7. However, these characters are not universally present in all of the species, and other characters must be employed: the single major dactylar claw on pereopods II-VII, the flat triangular molar process of the mandible, uropodal shape, and the presence of major anterolateral setae on the tergites of pereonites 2-4.
Within the genus Nannoniscus there is presently a striking diversity of morphol- ogies. Many of the species in this genus differ markedly from the type species N. oblongus Sars, 1870. Perhaps because these unique forms have often been described from finds of single individuals or samples from a single locality, workers have been reluctant to erect additional genera. Extensive collections have become available from a number of deep-sea sampling programs. The present study is based primarily on materials from the deep-sea sampling program of the Woods Hole Oceanographic In- stitution (Sanders et al., 1965; Hessler and Sanders, 1967; Sanders and Hessler, 1969). The program has sampled transects throughout the Atlantic Ocean, running out from shallow coastal waters into the abyss. Such transects are located off the northeastern United States (Gay Head—Bermuda transect), Surinam, northern Brazil, Argentina, southwest Africa, Angola, Senegal, and Ireland. Additional samples have come from the Bay of Biscay (J. Allen, University of Newcastle upon Tyne), the Canary Islands (J. Allen), and the Weddell Sea (J. Rankin, University of Connecticut). A list of stations is given in Table 1.
It has become apparent from these additional materials that the morphologies of many of the described Nannoniscus species which appeared to be unique, specific characters in fact recur repeatedly in other species, and hence the establishment of new genera is both desirable and necessary. This study undertakes to establish these new genera as is warranted, and to delimit their geographic and bathymetric distribu-
228
TABLE 1. Station data.
WHOI
Station Depth (m) Latitude Bermuda 1 1000 32°16.5'N Bermuda 2 1700 32°16.6'N Bermuda 4 1700 32°17.0'N Bermuda 5 2000 32°11.4'N Bermuda 6 1500 32°14.3'N Bermuda 7 2500 32°15'N Bermuda 8 1000 B22 lesuN HH 3 2900 38°47'N G1 2000 39°42'N LL 1 4977 35°35'N JJ 3 4540 33711335 ZN} OO 2 4667 33°0.67'N G9 2021 39°44.7'N Chain 35, dredge 12 770-805 07°09’S
61 2000 39°43 .2'N 62 2496 39°26'N 65 2891 38°46.8'N 66 2802 38°46.7'N 70 4680 36°23'N 73 1330-1470 39°46.5'N 84 4749 36°24.4'N 85 3834 37°59.2'N 92 4694 36°20'N 95 3753 38°33'’N 100 4743-4892 33°56.8'N 109 4750 36°25'N 118 1135=1153 32°19.4'N 32°19.0'N 119 2095-2223 32°15.8'N 32°16.1'N 120 5018-5023 34°43 .0'N 34°40.5'N 121 4800 35°50.0'N 122 4833 35°50.0'N 35°52.0’N 125 4825 37°24.0'N 37°26.0'N 126 3806 39°37.0'N 39°37.5'N 128 1254 39°46.5'N 131 2178 36°28.9'N 142 1624-1796 10°30.0'N 145 2185 10°36.0'N 149 3861 10°30.0'N 155 3730-3783 00°03.0'S 156 3459 00°46.0'S 00°46.5'S 159 834-939 07°58.0'S 167 943-1007 07°58.0'S 07°50.0'S 169 587 08°03.0'S 08°02.0'S 175 4667-4693 36°36'N 36°36'N 195 3797 14°49’S 14°40'S 197 4595-4597 10°29'S 199 3764-3779 9°47'S 9°49'S 200 2644-2754 9°41'S 9°43.5'S 201 1964-203 1 9°29'S
9225'S
Longitude
64°42.5'W 64°36.3'W 64°35'W 64°41.6'W 64°42'W 64°32.6'W 64°33'W 70°08’ W 70°39'W 67°25'W 68°39.6’W 65°2.2'W 70°38.3'W 34°25.5'W 70°37.8'W 70°33'’W 70°6.8'W 70°8.8'W 67°58'W 70°43.3'W 67°56'W 69°26.2'W 67°56'W 68°32'W 65°47'W 68°6.0'W 64°34.9'W 64°34.8'W 64°31.6’W 64°32.6'W 66°32.8’W 66°35.0’W 65°11.0'W 64°57.5'W 64°58 .0'W 65°54.0'W 65°50.0'W 66°47.0'W 66°44 .0'W 70°45.2'W 67°58.2'W 17°51.5'W 17°49.0'W 18°18.0'W 27°48.0'W 29°28.0'W 29°24.0'W 34°22.0'W 34°17.0'W 34°17.0'W 34°23.0'W 34°25.0'W 68°29'W 68°31'W 9°56'E 9°54'E 9°04" E 10°29'E 10°33'E 105508 LOWS74E 11°34’E INIS3)5y 183
TABLE 1. Continued.
Station Depth (m) Latitude Longitude 202 1427-1643 9°04'S 12°17’E 8°56'S 12°15’E 209 1501-1693 39°47.6'N 70°49.9'W 39°46'N 70°51.5'W 242 4382-4402 38°16.9'S 51°56.1'W 245 2707 367559709 53°01.4’W 247 5208-5223 43°33.0'S 48°58.1'W 256 3906-3917 37°40.9'S 52°19.3'W 259 3305-3317 B7alaous 52°45.0'W 287 4934-4980 13°16.0'N 54°52.2'W 13°15.8'N 54°53.1'W 293 1456-1518 8°58.0'N 54°04 .3'W 295 1000-1022 8°04.2'N 54°21.3'W 297 508-523 7°45.3'N 54°24.0'W 301 2487-2500 8°12.4'N 55°50.2'W 303 2842-2853 8°28.8'N 56°04.5'W 306 3392-3429 9°31.1'N 56°20.6'W 313 1491-1500 §1°32.2'N 12°35.9'W 321 2868-2890 50°12.3'N 13°35.8'W 323 3338-3356 50°08.3'N 13°53.7'W 50°08 .3'N 13°50.9'W 326 3859 50°04.9'N 14°23.8'W 50°05.3'N 14°24.8'W 328 4426-4435 50°04.7'N 15°44.8'W 330 4632 $0°43.5'N IESE ANY: 50°43.4'N 17°52.9'W Allen 33 1784 43°40.8'N 3°36'W 40 860 43°35.6'N 3°24.8'W 50 2379 43°46.7'N 3°38'’W 65 1922 46°15'N 4°50’ W 1969 Rankin 0022ES 3111 73°28.4'S 30°26.9'W
tions. Because of the great number of new species in the presently available materials, we will not attempt to describe all of the new species, but only to outline the com- position of the genera. Occasional reference will be made to some of the undescribed species. Our intention is to reduce the unnatural heterogeneity of some of the present genera and to introduce a framework to permit future phylogenetic, biogeographic, and ecological studies. A key to the genera is given in Table 2. The described species of the family are compiled in Table 3.
Institutional abbreviations used in this study follow: WHOI, Woods Hole Ocean- ographic Institution, Woods Hole, Massachusetts, USA; USNM, United States Mu- seum of Natural History, Washington, D.C., USA. Specimens without USNM num- bers are presently in the working collection of R. R. Hessler.
SYSTEMATICS Nannoniscidae Hansen, 1916 (Nannoniscini auctoris) Exiliniscus, new genus
Diagnosis.—Pereonites 6 and 7 free. Body hemicylindrical, elongate and narrow; length greater than 5 times tergal width of pereonite 2. Cephalon with massive rostral crest, forming concave face. Antenna I compact, with bulbous distal segment. Antenna II short, tends to be compact and robust; length approximately one-quarter of total body length; some flagellar segments fused. Mandible lacks palp.
Additional descriptive notes.—Propodus of pereopod II with robust, medium- length setae distally, | dorsal and 1 ventral, setting off dactylus; both setae about
230
TABLE 2. A key to the genera of the Nannoniscidae.
INannoniscidae swith) pereonitessorandiy) frees rer ererier itera ela ee rede eed intel ett) eng Nee ttt I Nannoniscidae with pereonites 6 and 7 fused medially ................. esse e eee eee e eee ee eee eee II le sPereonite 7 iusedawithapleonmecmrsmae citric aneve oes ae etch edetetey en -ia lc lionel ate Nannonisconus Pereonitem ano tetusedawithan] conan sere aero oc oar ee cr orci te len trer tenant 1 in Antenna lS-seementeds with) bulbous distalvanticle 22.7. seis sc elem sie ein cristo lensieielieietats D MMM SH Gas soowasaonocgddcd socoovbeanod bo ou bdodbooorouUDUD dU GaDD DUCE aGEES 3 PPPLomudinesostralucrestarantennay lac ompac tie rey jay 3 oes elon lee Neneiel tee tet Exiliniscus Nomostralicrestrantennall mot Compactyasen emt meaner ae seers claire ie lee eee oks Panetela 3. Body flattened and broad with expanded pleura and pleon ............----...+.- Austroniscus Body motiexceptionallystiattened or broadened) 25. 5.2. nee ite so lie teeter = 4
4. Female pleon with posterolateral spines; posterior pereopods not flattened for swimming; no opercular ventral medial spines; operculum indented distally ............. Nannoniscoides
Female pleon generally without posterolateral spines; sexual dimorphism of pleon shape; posterior pereopods flattened for swimming; opercular ventral medial spines; operculum
DMCA, seoccnessoopomadomenGuesabvocs poouduUDooUROomODOOHOmaAOSC Thaumastosoma II. Pereopod I robust and thickened, much more so than other pereopods, which are slender in COMET AS CA ek re RR ee eae a emer Eee eee ea es ce vay ahve Ma apa Ne ios aay eulero Genome Rapaniscus Pereoped Inonmal similar to;other pereopods mithickness (nates. ss re ste tere rae 5 SeySevetal major ventralemediall Spines, «tei ys ee waka n woes aoe ee Oo ches Regabellator Onexornonventralémedialespines) cease seine 6 oc eee eeeetertoles) weiss packs usd tchem acum reiors cere 6 OQ AMIGA I SS:GeemiGiiS soosscvaancoscecaddobouooedecetsopopocounsoUKdoDO™ Nannoniscoides ATCenn ale s=SeOMentecleer tani. eis nieces sacra ees nee aortas wie es SA EES arenes cllelavcls ot otaeeneme enema ier i 7. Penultimate segment of antenna I without shelf-like process; pleon with posterolateral Solve Rik Gi ciara cho-ulo ToL o Btn cre eG AM OIG On no CraCR Amn ae REN olor aeitue aitaa o feco ed ore ore Hebefustis Penultimate segment of antenna I with shelf-like process ...................0-- Nannoniscus
equally well developed. Posterior pereopods often with natatory setae. Female oper- culum (pleopod II) length approximately equal to width; length approximately one-half length of pleon. Pleon spade-shaped in dorsal view, i.e., tapering anteriorly to poste- riorly. Uropodal endopod long and narrow; exopod much reduced.
Type-species.—Exiliniscus clipeatus, new species.
Etymology.—Exiliniscus is taken from the Latin exilis, thin or slender. The gender of the name is masculine.
Remarks.—This genus is readily distinguished from most of the other Nannonis- cidae by its narrow and elongate body and the lack of fusion of pereonites 6 and 7. Exiliniscus is distinct from the other nannoniscid genus Panetela, new genus (which has an elongate body and lacks fusion of pereonites 6 and 7), in its well-developed rostral crest (cf. Figs. 1B and 2B with Fig. 5B), the compactness of antennae I and II (cf. Figs. 1E and 2G with Fig. 5D), and the lack of a mandibular palp. Exiliniscus is the only nannoniscid known to lack a mandibular palp. Nannoniscus hanseni Just, 1970 is transferred to Exiliniscus, new genus. This species clearly possesses the di- agnostic features of the genus. The presence or absence of a mandibular palp is not noted in Just’s description. Exiliniscus hanseni is distinct from the other species of the genus in lacking notches in the cephalon for the insertion of antennae.
This genus contains the following species: E. clipeatus, new species; E. hanseni (Just, 1970); and E. aculeatus, new species.
Distribution.—Exiliniscus clipeatus: northwest Atlantic Ocean, 3834-5023 m; E. hanseni: Jgrgen Brgnlund Fjord, Greenland, 80-90 m (Just, 1970); E. aculeatus: south- east equatorial Atlantic Ocean, 1964-3797 m. This genus has a wide bathymetric dis- tribution in the Atlantic Ocean, ranging from 80 to 5223 m. The stations at which the genus (including undescribed materials) has been taken are as follows: WHOI 65, 2891 m; WHOI 66, 2802 m; WHOI 84, 4749 m; WHOI 85, 3834 m; WHOI 95, 3753 m; WHOI 100, 4743-4892 m; WHOI 118, 1135-1153 m; WHOI 119, 2095—2223 m; WHOI 120, 5018-5023 m; WHOI 121, 4800 m; WHOI 122, 4833 m; WHOI 125, 4825 m; WHOI 142, 1624-1796 m; WHOI 145, 2185 m; WHOI 149, 3861 m; WHOI 159, 834-939 m; WHOI 167, 943-1007 m; WHOI 169, 587 m; WHOI 175, 4667-4693 m; WHOTI 195,
231
TABLE 3. A compilation of the nannoniscid species (* indicates generic type-species).
Genus
Nannoniscus
Nannonisconus
Austroniscus
Nannoniscoides
Hebefustis
Thaumastosoma
Exiliniscus
Rapaniscus
Species
acanthurus Birstein, 1963; aequiremis Hansen, 1916; affinis Hansen, 1916; analis Hansen, 1916; arcticus Hansen, 1916; australis Vanhoffen, 1914; bidens Vanhof- fen, 1914; camayae Menzies, 1962; caspius Sars, 1897; coalescus (Menzies and George, 1972); detrimentus Menzies and George, 1972; inermis Hansen, 1916; in- termedius, new species; laevis Menzies, 1962; laticeps Hansen, 1916; minutus Han- sen, 1916; muscarius Menzies and George, 1972; oblongus* Sars, 1870 (figured 1899); ovatus Menzies and George, 1972; perunis Menzies and George, 1972; ple- bejus Hansen, 1916; reticulatus Hansen, 1916; simplex Hansen, 1916; spinicornis Hansen, 1916; teres, new species
latipleonus* Schultz, 1966
acutus Birstein, 1970; groenlandicus (Hansen, 1916); karamani Birstein, 1962; ovalis* Vanhoffen, 1914; rotundatus Vanhoffen, 1914; vinogradovi (Gurjanova, 1950)
angulatus* Hansen, 1916; biscutatus Siebenaller and Hessler, 1977; coronarius Sie- benaller and Hessler, 1977; excavatifrons (Birstein, 1970); gigas Siebenaller and Hessler, 1977; latediffusus Siebenaller and Hessler, 1977
alleni Siebenaller and Hessler, 1977; cornutus Siebenaller and Hessler, 1977; dispar Siebenaller and Hessler, 1977; hexadentium Siebenaller and Hessler, 1977; hirsutus (Menzies, 1962); mollicellus Siebenaller and Hessler, 1977; par Siebenaller and Hessler, 1977; primitivus (Menzies, 1962); robustus (Birstein, 1963); vafer* Sie- benaller and Hessler, 1977
distinctum (Birstein, 1963); platycarpus* Hessler, 1970; tenue Hessler, 1976 aculeatus, new species; clipeatus*, new species; hanseni (Just, 1970)
crassipes (Hansen, 1916); dewdneyi*, new species
Panetela tenella (Birstein 1963); wolffit, new species
Regabellator armatus (Hansen, 1916); profugus*, new species
3797 m; WHOI 197, 4595 m; WHOI 200, 2644-2754 m; WHOI 201, 1964-2031 m; WHOI 242, 4382-4402 m; WHOI 247, 5208-5223 m; WHOI 259, 3305-3317 m; WHOI 287, 4934-4980 m; WHOI 293, 1456-1518 m; WHOI 295, 1000-1022 m; WHOI 301, 2487-2500 m; WHOI 303, 2842-2853 m; WHOI 306, 3392-3429 m; WHOI 313, 1491- 1500 m; WHOI 321, 2868-2890 m; WHOI 323, 3338-3356 m; WHOI 326, 3859 m; WHOI 328, 4426-4435 m; WHOI 330, 4632 m; WHOI HH 3, 2900 m; WHOI JJ 3, 4540 m; WHOI LL 1, 4977 m; WHOI OO 2, 4667 m; WHOI Bermuda 1, 1000 m; WHOI Bermuda 2, 1700 m; WHOI Bermuda 4, 1700 m; WHOI Bermuda 5, 2000 m; WHOI Bermuda 6, 1500 m; WHOI Bermuda 7, 2500 m; WHOI Bermuda 8, 1000 m; ALLEN 40, 860 m; ALLEN S50, 2379 m; ALLEN 65, 1922 m; 1969 RANKIN 0022ES, 3111 m.
Exiliniscus clipeatus, new species Figure 1
Holotype.—WHOI 85, brooding 2, 2.7 mm long, USNM 184182.
Other material.—WHOI 84, | individual; WHOI 120, 1 individual; WHOI 121, 2 individuals; WHOI 122, 5 individuals; WHOI 175, 1| individual.
Distribution.—Northwest Atlantic Ocean, 3834-5023 m.
Etymology.—Latin, armed with a shield.
Diagnosis.—Body length 6.6 times tergal width of pereonite 2. Pereonite 4 length to width ratio (I/w) 0.9. Pereonite 5 (I/w) 1.1. Pleon (I/w) 1.08; width 0.8 times width of pereonite 2. Rostral crest not protruding far forward, bluntly rounded. Antenna I with projection forming full shield over distal bulbous article. Antenna II robust; segment 5 (I/w) 1.38. Uropodal endopod (1/w) 3.13; exopod reduced, (I/w) 1.5; endopod length 8.33 times exopod length. Operculum (@ pleopod II) rounded; distal margin straight.
Additional descriptive notes.—Pereopods I and II robust. Pereopod I carpus and
Fic. 1. Exiliniscus clipeatus, new species, WHOL 8S. A. brooding 2 (holotype), dorsal view; B. preparatory 2, lateral view; C. juvenile 2 left mandible; D. juvenile 2, maxilliped; E. brooding 2 (holotype) right antennae I and II (dorsal view), s: shield; F. brooding 2 (holotype) antenna I and base of antenna II, lateral view, s: shield; G. brooding 2 (holotype) right uropod; H. brooding 2 (holotype) operculum (pleopod IJ); I. juvenile 2 left pereopod I; J. juvenile 2 left pereopod II; K. juvenile 2 left pereopod VI.
propodus of approximately equal length; carpus with 3-4 robust setae on ventral sur- face; propodus with 1. Pereopod II carpus somewhat longer than propodus; carpus with 5 robust setae on ventral surface, propodus distal seta on dorsal surface somewhat longer than ventral seta. Pereopod VI propodus with natatory setae; limb slender, carpus much longer than propodus.
Remarks.—Exiliniscus clipeatus, new species, is readily distinguished from the other species of the genus by the well-developed shield, stemming from segment 2, which fully envelops the bulbous distal article of antenna I dorsally. Other distinctive features include the dimensions of pereonites 4 and 5, the length and shape of the uropodal rami, and the robustness of antennae II.
K
Fic. 2. Exiliniscus aculeatus, new species, WHO! 201. A. preparatory 2 (holotype), dorsal view; B. preparatory 2 (holotype), lateral view; C. brooding @ maxilliped; D. and E. brooding 2? left mandible; F. brooding 2 pereopod I; G. preparatory 2 (holotype) antennae I and II; H. preparatory 2 (holotype) antenna I and base of antenna II; I. brooding 2 pereopod VI; J. preparatory 2 (holotype) right uropod, in situ; K. preparatory 2 (holotype) operculum (pleopod II), ventral view; L. brooding 2 pereopod II.
=<
Exiliniscus aculeatus, new species Figure 2
Holotype.—WHOI 201, preparatory 2, 2.3 mm long, USNM 184183.
Other material.—WHOI 201, 11 specimens; WHOI 200, 3 specimens; WHOI 195, 4 individuals and 2 fragments.
Distribution.—Southeast equatorial Atlantic Ocean, 1964-3797 m.
Etymology.—Latin, sharp, pointed, stinging.
Diagnosis.—Body length 5.6 times tergal width of pereonite 2. Pereonites 3, 4, and 5 broader than long. Pereonite 3 length to width ratio (I/w) 0.6; peronite 4 (I/w) 0.75; peronite 5 (I/w) 0.8. Pleon somewhat elongate; (I/w) 1.38; width 0.67 times width of pereonite 2. Rostral crest drawn to a point. Antenna I bulbous distal segment ex- posed, not fully shielded by projection. Antenna II relatively thin; segment 5 (I/w) 2.65.
234
Uropodal endopod I/w 3.0; exopod I/w 4.5; endopod length 2.7 times exopod length. Female operculum elongate, oval-shaped, tapering distally.
Additional descriptive notes. —Pereopod I relatively slender; propodus with 2 ro- bust setae distally; carpus with 4 robust setae ventrally. Pereopod II relatively slender; carpus with with 4 robust setae ventrally. Pereopod VI robust, carpus somewhat longer than propodus. Mandible with incisor processes sharply pointed; lacinia mobilis with well-developed and pointed teeth.
Remarks.—Exiliniscus aculeatus can be distinguished from the other species of the genus by its pointed rostral crest, the relatively slender anterior pereopods, and the shape of the 2 operculum.
Rapaniscus, new genus
Diagnosis.—Pereonites 6 and 7 fused medially. Antenna I 5-segmented; distal segment bulbous; article 4 with well-developed, shelf-like process. Pereopod I massive, carpus broad, bearing long robust setae; carpus and propodus of approximately equal length. Pereopods II-VI slender. Body length approximately 3.4 times tergal width of pereonite 2. Females with large recurved ventral medial spine on operculum or venter of preopercular segments. Mandible with palp.
Additional descriptive notes. —Pleon length approximately equal to width. Where recurved ventral medial spine is present on 2 operculum, dd lack the spine. Female operculum (pleopod II) oval, blunted distally.
Type-species.—Rapaniscus dewdneyi, new species.
Etymology.—Rapaniscus is from the Latin rapax, seizing, snatching, grasping. The name is masculine.
Remarks.—Rapaniscus is readily distinguished from the other nannoniscid genera which have a 5-segmented antenna I with a bulbous distal article and fusion of per- eonites 6 and 7 by the massive development of pereopod I (see Fig. 4G), which is more heavily developed than the limb of other nannoniscid genera. Nannoniscus cras- sipes (Hansen, 1916), with a massive pereopod I and a recurved ventral medial spine stemming from the venter of pereonite 7, is transferred to Rapaniscus.
The genus contains the following species: Rapaniscus dewdneyi, new species, and R. crassipes (Hansen, 1916), and an undescribed species.
Distribution.—Rapaniscus dewdneyi: northwestern Atlantic Ocean, 1254-2223 m. R. crassipes: North and equatorial Atlantic Ocean, 220-2754 m. The stations at which the genus has been taken are as follows: R. crassipes (Hansen, 1916): Off Lofoten Islands, at Skraaven, 220-457 m (G. O. Sars, 1899, as new specimens of Nannoniscus oblongus); WHOI G1, 2000 m; WHOI 73, 1330-1470 m; WHOI 145, 2185 m; WHOI 200, 2644-2754 m; WHOI 209, 1501-1693 m; R. dewdneyi, new species: WHOI G9, 2021 m; WHOI 61, 2000 m; WHOI 119, 2095-2223 m; WHOI 128, 1254 m; Rapaniscus species: WHOI 95, 3753 m; WHOI 118, 1135-1153 m; WHOI 119, 2095-2223 m; WHOI 256, 3906-3917 m; WHOI 287, 4934-4980 m; WHOI 306, 3392-3429 m; WHOI 321, 2868-2890 m; WHOI 330, 4632 m.
Rapaniscus dewdneyi, new species Figure 3
Holotype. —WHOI 209, preparatory 2, 1.4 mm long, USNM 184184.
Paratype.—WHOI 209, male, 1.2 mm long, USNM 184185.
Other material—WHOI G9, 1 specimen; WHOI 61, 4 specimens; WHOI 119, 1 specimen; WHOI 128, 4 specimens; WHOI 131, 2 specimens.
Distribution.—Northwestern Atlantic Ocean, 1253-2223 m.
Etymclogy.—For our colleague, Dewdney Somero, with whom we have closely worked, whose counsel we respect, and whose efforts in support of research continue through the Dewdney Endowment.
Diagnosis. —Body length 3.5 (2), 3.6 (3) times tergal width of pereonite 2. Per- eonite 4 width 0.8 times tergal width of pereonite 2. Pereonite 5 0.6 (2), 0.8 (d) times
235
Fic. 3. Rapaniscus dewdneyi, new species, WHOI 209. A. preparatory 2 (holotype), dorsal view; B. preparatory 2 (holotype), lateral view; C. copulatory d (paratype), dorsal view; D. preparatory ? (holotype) antenna I; E. and F. brooding 2 left mandible; G. brooding 2 antennae I and II; H. copulatory d (paratype) antenna I; I. brooding 2 maxilliped; J= brooding 2 operculum (pleopod II); K. copulatory d (paratype) pleopods I; L. copulatory ¢ (paratype), ventral view of pleon; M. copulatory d (paratype) pleon, lateral view; N. brooding 2 pereopod VI.
width of pereonite 2. Pleon length approximately equal to width; pleon tapers poste- riorly. No sexual dimorphism of pleon shape. Pleon width 0.72 (2), 0.76 (¢) times width of pereonite 2. Cephalic width 0.84 (2), 0.91 (3d) times tergal width of pereonite 2. Uropod length 0.42 times length of pleon (measured in dorsal view). Endopod elon- gate and slender; length 5.6 (2), 4.4 (d) times width (I/w). Exopod short; (I/w) 3.4. Endopod length 2.6 times length of exopod. Male and @ with thin ventral medial spine on pereonite 7. Female operculum (pleopod IJ) relatively flat, not vaulted. Remarks.—Rapaniscus dewdneyi was taken at the same station as Rapaniscus crassipes (WHOI 209). Rapaniscus dewdneyi can be differentiated from R. crassipes by the shape of the uropodal endopod, elongate in R. dewdneyi, much shorter in R.
236
Fic. 4. Rapaniscus crassipes (Hansen, 1916), WHOI 209. A. preparatory °, dorsal view; B. preparatory 2, lateral view; C. brooding 2 left mandibular incisors; D. brooding 2 left mandible; E. preparatory 2 antenna I and base of antenna II; F. brooding 2° pereopod VI; G. brooding 2 pereopod I; H. brooding 2 ventral view of pleon; I. brooding 2 maxilliped.
crassipes (Figs. 3J, 4H). The body of R. crassipes is more robust, the pleon more blunt posteriorly, the ventral medial spine is elongate and robust, and the ? operculum is deeply vaulted (Figs. 3B, 4B). These two species may be distinguished from an undescribed species of Rapaniscus on the shape of the uropodal endopod, and the sexual dimorphism of the pleon, which is squared in the ¢ of the undescribed species, a condition unique among the species of the genus.
Panetela, new genus
Type-species.—Panetela wolffi, new species.
Diagnosis.—Pereonites 6 and 7 free. Body cylindrical or hemicylindrical, narrow and elongate; length greater than approximately 5 times tergal width of pereonite 2. Cephalon lacks massive rostral crest. Antenna I 5-segmented, with bulbous distal ar- ticle; segment 2 slender. Mandible with 3-segmented palp.
Additional descriptive notes. —Antenna II generally narrow and long relative to body length. Pereopods moderately robust; posterior pereopods may have natatory setae. Shape of uropods and ? operculum (pleopod II) may vary interspecifically. Some species possess a ventral medial spine, stemming from either the venter of per- eonite 7 or from the operculum.
Etymology.—Panetela is taken from Spanish, referring to the slender, cigar-like body form. The gender is feminine.
237
Remarks.—Nannoniscus tenellus Birstein, 1963 is transferred to Panetela because it lacks fusion of pereonites 6 and 7, does not have a massive rostral crest, and has a 5-segmented antenna I with a bulbous distal article. Also of note is the slender and elongate antenna II which contrasts with the more robust antenna II in Exiliniscus. Wolff (1975, 1976) notes the occurrence of an unidentified 2 nannoniscid taken from a Thalassia rhizome in the Cayman Trench at 6800 m at a station of the R/V Akademik Kurchatov (1242A) (see Fig. 2, part O of Wolff [1976]). This specimen is most prob- ably a member of Panetela.
Panetela is readily distinguished from most of the other Nannoniscidae by its narrow and elongate body, and the lack of fusion of pereonites 6 and 7. In the overall slender appearance of the body it is very similar to Exiliniscus. However, Panetela may be easily distinguished by its lack of a protruding rostral crest, the less compact antenna I (Figs. IE, SE), the presence of a 3-segmented mandibular palp, and its more narrow and elongate antenna II (Figs. IE, 2G, 5D).
The genus contains: P. tenella (Birstein, 1963) and P. wolffi, new species.
Distribution.—North and South Atlantic Ocean, northwest Pacific Ocean, 770- 5495 m. The stations at which the genus has been taken are as follows: WHOI 62, 2496 m; WHOI 66, 2802 m; WHOI 84, 4749 m; WHOI 92, 4694 m; WHOI 95, 3753 m; WHOI 100, 4743-4892 m:; WHOI 109, 4750 m; WHOI i118, 1135-1153 m; WHOT 119, 2095-2223 m; WHOI 120, 5018-5023 m; WHOI 121, 4800 m; WHOI 122, 4833 m; WHOI 125, 4825 m: WHOI 126, 3806 m; WHOI 128, 1254 m; WHOI 142, 1624-1796 m:; WHOI 145, 2145 m; WHOI 156, 3459 m; WHOI 167, 943-1007 m; WHOI 199, 3764- 3799 m; WHOI 200, 2644-2754 m; WHOI 201, 1964-2031 m; WHOI 202, 1427-1643 m; WHOI 242, 4382-4402 m; WHOI 245, 2707 m; WHOI 247, 5208-5223 m; WHOI 259, 3305-3317 m; WHOI 287, 4934-4980 m; WHOI 293, 1456-1518 m; WHOI 301, 2487-2500 m; WHOI 303, 2842-2853 m; WHOI 323, 3338-3356 m; WHOI 326, 3859 m; WHOI 330, 4632 m; WHOI Bermuda 7, 2500 m; WHOI Chain 35, Dredge 12, 770- 805 m; ALLEN 33, 1784 m; Kurchatov Station 3575, 5461-5495 m (Birstein, 1963).
Panetela wolffi, new species Figure 5 :
Holotype.—WHOI 201, preparatory 2, 2.0 mm long, USNM 184186.
Paratype. —WHOI 202, copulatory 6, 1.35 mm long, USNM 184187.
Other material.—WHOI 201, 19 individuals; WHOI 202, 4 individuals.
Distribution. —Equatorial southeastern Atlantic Ocean, 1427-2031 m.
Etymology.—After Torben Wolff.
Diagnosis.—Body length 8 (2), 6.4 (3d) times tergal width of pereonite 2. Body appears very elongate, pereonites 4—7 0.46 times body length. Female pleon rounded distally; ¢ pleon somewhat squared distally. Uropodal endopod elongate; exopod very slender and short. Pereopods VI and VII with natatory setae. No ventral medial spines.
Remarks.—Panetela wolffi has a very elongate appearance due to the length of pereonites 3-7. This contrasts with the condition in P. tenella (Birstein, 1963) in which the body is more compact. Also, the operculum (¢ pleopod II) of P. wolffi is more pear-shaped and elongate than that of P. tenella. The sexual dimorphism of pleonar shape in P. wolffi should also be noted.
Regabellator, new genus
Diagnosis.—Pereonites 6 and 7 fused. Body length approximately 3.4 times tergal width of pereonite 2. Antenna I 5-segmented, with bulbous terminal article; segment 4 with long lateral projection. Two large medial spines on venters of pereonites 6 and 7. Posterior spine with broad basal region; anterior spine narrower, generally directed ventrally or slightly anteriorly. Short spine-like processes may be present on ventral medial surfaces of other pereonal segments. Pereopod I with anteriorly directed coxal plate bearing small robust seta. Propodus and carpus devoid of long robust setae dor- sally and ventrally. (However, small robust terminal seta is present.) Pereopods I-IV
238
Fic. 5. Panetela wolffi, new species, WHOI 201. A. preparatory 2 (holotype), dorsal view; B. preparatory 2 (holotype), lateral view; C. brooding @ left mandible; D. preparatory ? (holotype) antennae I and I; E. preparatory 2 (holotype) antenna I and base of antenna II; F. brooding 2 maxilliped; G. brooding 2 pleon, ventral view; H. brooding ? right uropod; I. juvenile ° right pereopod I; J. brooding right pereopod II;
K. brooding 2 left pereopod VI, WHOI 202, copulatory 3 (paratype); L. dorsal view; M. antenna I; N. antennae I and II; O. left uropod.
with very long robust setae from ventral and dorsal surfaces of propodus and carpus. Pereopods V-—VII not broadened, without well-developed natatory setae. Mandible with palp.
Additional descriptive notes.—Pereonites 4—7 distinctly narrower than anterior pereonites. Pleon tapers posteriorly, with ventral surface somewhat vaulted, deepening from lateral margins to branchial chamber. Posteriorly, lateral pleonar margins tuck under, setting off anal plates and uropods from rest of pleon. Uropods set close together and almost terminal. Uropods with small exopod; endopod variable in length.
Type-species.—Regabellator profugus, new species.
239
Fic. 6. Regabellator profugus, new species, WHOI 201. A. preparatory 2 (holotype), dorsal view; B. preparatory ¢ (holotype), lateral view; C. preparatory 2 (holotype) left antenna I; D. preparatory 2 (ho- lotype) left uropod; E. brooding 2 left mandible; F. brooding 2 maxilliped; G. 3 (paratype), dorsal view; H. d (paratype) antenna II; I. 3 (paratype) antenna I; J. d (paratype) right uropod; K. d (paratype) pleo- pods I. .
Etymology.—Regabellator is masculine, taken from the Latin regalis and bellator, regal warrior, referring to the presence of multiple ventral medial spines.
Remarks.—Nannoniscus armatus Hansen, 1916 is transferred to Regabellator. Regabellator is similar to described species of Thaumastasoma (T. platycarpus Hes- sler, 1970 and T. tenue Hessler, 1970) which also possess 2 major ventral medial spines (Fig. 11B). These 2 species also show similarities to Regabellator in the shape of the 2 pleon and the close positioning of the uropods to the midline. Thaumastasoma has been removed from the Desmosomatidae to the Nannoniscidae by Siebenaller and Hessler (1977).
These two genera differ in the first antenna, which is 6-segmented and unmodified in Thaumastasoma (Fig. 11C), and 5-segmented with a bulbous distal article and a shelf-like process from the penultimate article in Regabellator (Fig. 6C). Thaumas-
240
Fic. 7. Regabellator profugus, new species, WHOI 201, brooding 2. A. right pereopod I; B. left pereopod II; C. left pereopod VI.
tasoma has long robust setae on the carpus and propodus of pereopod I; Regabellator lacks these. Thaumastasoma lacks fusion of pereonites 6 and 7. Regabellator does not display sexual dimorphism in the shape of the pleon; neither are the carpi of the posterior pereopods broadened (Figs. 7C, 11E). These features contrast with the con- dition in Thaumastasoma. The species of Regabellator and undescribed material in our collection do not have a spine on the 2 operculum.
Regabellator is readily distinguished from the other nannoniscid genera which have an antenna I with a bulbous distal article and fusion of pereonites 6 and 7 by the presence of multiple ventral medial spines. Sexual dimorphism, aside from the differ- ences in the pleopods, is most apparent in the much more robust antenna II of the 3: the antenna I of the ¢ and @ are identical, the typical situation in the Nannonis- cidae.
Regabellator contains the following species: R. profugus, new species, and R. armatus (Hansen, 1916).
Distribution.—Regabellator profugus, new species: southeast Atlantic Ocean, 1964-3797 m: R. armatus: North Atlantic Ocean, 2379-4435 m. The stations at which the genus (including undescribed material) has been taken are as follows: R. armatus (Hansen, 1916): Ingolf Station 38, 1870 fm [=3403 m] (Hansen, 1916); WHOI 85, 3834 m: WHOI 149, 3861 m; WHOI 328, 4426-4435 m; ALLEN 50, 2379 m; R. profugus, new species: WHOI 195, 3797 m; WHOI 200, 2644-2754 m; WHOI 201, 1964-2031 m; Regabellator species: WHOI 70, 4680 m; WHOI 256, 4563 m.
Regabellator profugus, new species Figures 6, 7
Holotype. —WHOI 201, preparatory 2, 3.1 mm long, USNM 184188.
Paratype. —WHOI 201, 3, 2.5 mm long, USNM 1841839.
Other material. —WHOI 195, 1 specimen; WHOI 200, | specimen.
Distribution. —Southeastern Atlantic Ocean, 1964-2754 m.
Etymology.—Latin, wandering, fleeing.
Diagnosis.—Body elongate; length 3.4 (2), 3.8 (3) times width of pereonite 2. Pereonite 4 length 0.5 (2), 0.6 (3) times width; width 0.77 (2), 0.73 (¢) times width of pereonite 2. Pereonite 5 rectangular; length to width ratio (I/w) 0.4; width 0.63 (2), 0.7 (¢) times width of pereonite 2. Pereonites 6 and 7 and pleon broaden slightly. Pleon width 0.64 (2), 0.72 (3) times width of pereonite 2; length 1.1 times width. Uropods 0.35 times length of pleon (latter measured in dorsal view). Endopod long; (I/w) 4.4 (@), 4.6(3). Exopod short; (I/w) 4.4 (2), 2.5(d¢). Endopod length S-O1G2) GSE.
241
(3) times length of exopod. Pereopod II carpus with 3 long setae dorsally; 8 ventrally, increasing in length distally. Antenna I segment 2 with protuberances on distal edge, one of which is much more developed than others. Male pleopod I (1/w) 3.15; broadest proximally, squared distally. Lateral lobes developed as protuberances.
Remarks.—Characters which vary among Regabellator species are the length of the uropodal endopod, the relative proportions of the endopod and the exopod, and the large differences in the number of setae on the carpus of pereopod II. Note that the 6 body width is much more uniform (i.e., relatively wider posteriorly) than the 2 (Fig. 6A, 6G).
Nannoniscus Sars, 1870
Type-species.—Nannoniscus oblongus Sars, 1870 (figured 1899).
Diagnosis.—(Cf. Hansen, 1916.) Pereonites 6 and 7 fused medially. Body length generally less than 4 times tergal width of pereonite 2. Antenna I 5-segmented, with bulbous distal article. Pereopods I and II about equally robust. Mandible with 3-seg- mented palp. Uropods generally biramous.
Additional descriptive notes.—Species may have a ventral medial spine stemming from the venters of pereonites 6 or 7, or from the 2 opeiculum. Antenna II generally long and slender, more robust in 6 6. Body is generally depressed and generally less than 4 times the tergal width of pereonite 2; however, exceptions occur.
Remarks.—The genus consists of relatively unspecialized morphologies typical of the Nannoniscidae (1.e., have a 5-segmented antenna I with a bulbous distal article, and fusion medially of pereonites 6 and 7). More specialized forms are typified by the new genera Exiliniscus, Panetela, Rapaniscus, and Regabellator. Exiliniscus and Panetela both lack fusion of pereonites 6 and 7, which is generally a diagnostic feature of the family. However, both of the genera have 5-segmented antennae I with a bulbous distal article. Rapaniscus has a highly modified pereopod I; Regabellator has several ventral medial spines. Both of these genera also have the typical combination of nan- noniscid features (i.e., a S-segmented antenna I with a bulbous distal article and fusion medially of pereonites 6 and 7).
There still remain within the genus Nannoniscus several morphologies which may, at a later date, require elevation to generic rank (e.g., Nannoniscus muscarius and N. ovatus; N. detrimentus). Because of a possible intergradation of these forms with the more typical Nannoniscus form, we leave this question open.
Nannoniscus intermedius, new species, which is discussed below, possesses fea- tures which suggest that it should be assigned to the genus Nannonisconus Schultz. Nannoniscus intermedius is strikingly similar to general features of Nannonisconus latipleonus Schultz, but differs from Schultz’s diagnosis of the genus Nannonisconus in that it lacks fusion of pereonite 7 with the pleon. Other than Nannonisconus lati- pleonus, no species with fusion of pereonite 7 with the pleon has been reported. Future investigations may reveal that the diagnostic characteristic of Nannonisconus is not the fusion of pereonite 7 with the pleon, but rather the characteristic proportions and shape of the pleon. However, we have refrained from redefining the genus Nannon- ISCONUS.
Table 3 lists the species of Nannoniscus. The following species have been trans- ferred from Nannoniscus to other genera in this study: N. armatus Hansen, 1916 to Regabellator, new genus; N. crassipes Hansen, 1916 to Rapaniscus, new genus; N. hanseni Just, 1970 to Exiliniscus, new genus; and N. tenellus Birstein, 1963 to Pa- netela, new genus. For reassignments of other species of Nannoniscus see Siebenaller and Hessler (1977).
Nannoniscus intermedius, new species Figure 8
Holotype. —WHOI 297, preparatory 2, 2.7 mm long, USNM 184190. Other material.—WHOI 297, 6 individuals.
242
Fic. 8. Nannoniscus intermedius, new species, WHOI 297, preparatory 2 (holotype). A. dorsal view; B. enlargement of the flap-like fold of pereonite 5; C. operculum (pleopod II); D. lateral view of left antenna I; E. right uropod, in situ; F. right pereopod I.
Distribution.—Equatorial west Atlantic Ocean, 508-523 m.
Etymology.—Latin, intermediate.
Diagnosis. —Body length 3.5 times tergal width of pereonite 2. Pleon broad, 0.9 times width of pereonite 2. Pleon with posterolateral spines. Cephalon narrow, 0.7 times tergal width of pereonite 2. Pereonite | lateral margins projecting strongly for- ward. Pereonite 5 anterolateral margins with ventrally projecting flaps. Uropodal en- dopod slender, length to width ratio (I/w) 6.4. Exopod slender and elongate; (I/w) 5.0. Endopod 2.2 times length of exopod. Female operculum (pleopod II) pear-shaped.
Remarks.—This species is very similar to Nannonisconus latipleonus Schultz, 1966 in the shape and width of the pleon (cf. Fig. 15). However, Nannonisconus latipleonus has pereonite 7 fused to the pleon. Nannoniscus intermedius can be readily distinguished from the other species of the genus Nannoniscus on the basis of the anterior margins of pereonite 5 and the protrusions anteriorly of the lateral margins of pereonite 1.
Nannoniscus teres, new species Figure 9
Holotype. —WHOI 328, preparatory 2, 4.2 mm long, USNM 184191.
Paratype.—WHOI 328, copulatory 6, 4mm long, USNM 184192.
Other material.—WHOI 328, 2 individuals.
Distribution.—Northeast Atlantic Ocean, 4426-4435 m.
Etymology.—Latin, refined, elegant.
Diagnosis.—Body length 3.1 (2), 3.0 (d) times tergal width of pereonite 2. Cephalon broad, 0.86 (¢), 0.77 (3) times width of pereonite 2. Pereonite | with lateral margins projecting anteriorly. Pleon tapering to a point, triangular in shape; ¢d with stout spine projecting from apex. Female operculum (pleopod I) pear-shaped with medial spine stemming from proximal surface. Male pleopods I with well-developed
243
Fic. 9. Nannoniscus teres, new species, WHOI 328. A. preparatory 2 (holotype), dorsal view; B, pre- paratory 2 (holotype) left antenna I and base of antenna II; C. preparatory 2 (holotype) right uropod; D. preparatory 2 (holotype), lateral view of operculum (pleopod II); E. preparatory 2 (holotype) left pereopod I; F. preparatory 2 (holotype) operculum (pleopod II), ventral view; G. copulatory d (paratype), dorsal view; H. copulatory ¢ (paratype) pleopods I; I. copulatory d¢ (paratype) left antenna I; J. copulatory ¢ (paratype) pleon, ventral view; K. copulatory d (paratype) right uropod; L. copulatory d (paratype) right pereopod II.
distolateral and distomedial lobes. Uropods small. Endopod 1.5 (@), 2 (d) times length of exopod. Endopod length to width ratio (I/w) 4.6 (2), 4.8 (¢). Exopod (I/w) 5.5 (2), 328)(6 ):
Remarks.—Although this species is not unique in possessing a triangular-shaped pleon (cf. N. acanthurus Birstein, 1963), it is singular in that the d has a spine stem- ming from the apex. The two species are very similar overall, but differ inter alia in the shape of the uropods and the distal margins of the d pleopods I.
Austroniscus Vanhoffen, 1914 Figure 10
Synonymy.—Nannoniscella Hansen, 1916 (Birstein, 1962). Diagnosis.—Body flattened; pereon and pleon expanded laterally into flat marginal flanges; on anterior pereonites, expansions extending anteriorly. Pleon without pos-
244
iy
ie
Fic. 10. Austroniscus vinogradovi (Gurjanova, 1950). A. dorsal view; B. cephalon; C. maxilliped; D. 2 operculum (redrawn from Gurjanova, 1950). Austroniscus No. 6 (undescribed species, WHOI Station 195), preparatory 2. E. pleon, ventral view.
terolateral spines; no ventral spines on body or operculum. Branchial chamber rela- tively small. Antenna I 6-segmented, with unspecialized distal articles. Pereopod I with conspicuous, anteriorly projecting epimere; where known, pereopod I of similar size to pereopod II and III. Pereopods V—VII not especially expanded for swimming, with only a few scattered swimming setae.
Additional descriptive notes.—A rostrum may or may not be well developed; where present, it may be slender or broad. On one undescribed species from WHOI 247, antenna I on mature 3 has 9 articles with numerous aesthetascs, as opposed to the single aesthetasc of the other species. On another undescribed species from WHOI 155, WHOI 195, and WHOI 245, pereonite 7 is not developed laterally. This is the only known case where pereonites 6 and 7 are fused in the midline region. On many species, lateral expansion of pereonites 5-7 is so great that the base of the pereopods is only halfway from the midline; this trend is emphasized going from 5 to 7. On mature 33, pleopod I exhibits a range of morphologies. For A. rotundatus and A. ovalis Vanhoffen, 1914, its medial lobe is rounded and extends only a short distance beyond the small, hook-like lateral lobes. On A. karamani Birstein, 1962, the medial lobe is long and pointed, and the lateral lobes are large but not hooked. An undescribed species from WHOI 195 is intermediate, having long but rounded medial lobes.
Type-species.—Austroniscus ovalis Vanhoffen, 1914 designated by Birstein (1962:34).
Remarks.—Vanhoffen’s diagnosis contained a single character, the unspecialized flagellum of antenna I. The addition of other species has demonstrated the presence of other features, the most notable of which is the flat marginal expansions of the pereon and pleon. Menzies and Pettit (1956) correctly removed A. ectiformis Vanhot-
tN _ in
Fic. 11. Thaumastosoma platycarpus Hessler, 1970. A. preparatory °, dorsal view; B. preparatory °, lateral view; C. brooding 2 antenna I and base of antenna II; D. brooding 2 left mandible; E. brooding 2 pereopod V (from Hessler, 1970).
fen, 1914 and placed it in Caecianiropsis. Birstein (1970) gives a key to the six currently described species. Our collection contains several undescribed species.
Distribution.—Austroniscus ovalis: Antarctic Indian Ocean, 70-385 m. A. rotun- datus: Antarctic Indian Ocean, 70-385 m. A. groenlandicus: W. Greenland, 10-132 m. A. karamani: E. of Japan, 5000-5450 m. A. acutus: E. of Japan, 5005-6135 m. A. vinogradovi: Kamchatka Sea (Avachin Bay), 125 m. Undescribed material: northern, equatorial, and southwestern Atlantic Ocean, 1000-5600 m; east equatorial Pacific Ocean, 4800-5100 m.
Thaumastosoma Hessler, 1970 Figure 11
Synonymy.—Desmosoma (part) Birstein, 1963.
Diagnosis.—Body slender, not depressed. Cephalon without rostrum. Pereonites 5-7 and pleon with small lateral flanges; pereonites 6 and 7 not fused; pereonite 7 venter and @ pleopod II with medial, posteriorly directed spine; pleon with postero- lateral spines on mature d; presence of small spines variable on 2. Antenna | 6-segmented, with unspecialized distal articles. Mouthparts produced conspicuously, accompanied by many modifications of specific appendages (see Additional descriptive notes, below). Mandible with well-developed palp. Pereopod I stouter than pereo- pod II.
Additional descriptive notes.—Mandible elongate; incisor process bent forward; lacinia mobilis membranous. Maxilliped with unusually elongate coupling hooks; palp segments 2-4 produced forward medially such that on article 3 the medial setae are distributed in an arc on the ventral surface of the article, rather than from the disto-
246
Fic. 12. Nannoniscoides angulatus Hansen, 1916. A. 3, dorsal view; B. d antenna I; C. 3, ventral view of pleon and pereonites 6 and 7 (from Just, 1970).
medial margin; joint between articles 2 and 3 angles distomedially. Basal endite of maxilliped II less than half the length of the other lobes.
Type-species.—Thaumastosoma platycarpus Hessler, 1970.
Remarks.—This genus was first regarded as being part of the Desmosomatidae (Hessler, 1970; Birstein, 1963). At that time, the distinction between that family and the closely related Nannoniscidae was still unresolved. When their differences were finally clarified, it became obvious that Thaumastosoma must be a nannoniscid (Sie- benaller and Hessler, 1977).
Distribution. —Thaumastosoma platycarpus: northwestern Atlantic Ocean, 2886 m. T. tenue: northwestern Atlantic Ocean, 2886-3753 m. 7. distinctum: northwestern Pacific Ocean, 5680-5690 m. Undescribed material: northern, equatorial, and south- western Atlantic Ocean, 1000-5600 m; eastern equatorial Pacific Ocean, 4800-5100 m.
Nannoniscoides Hansen, 1916 Figures 12, 13
Diagnosis. —Antenna I unspecialized, 6 (or rarely 7) segmented. Pleon with pos- terolateral spines. Operculum (? pleopod II) elongate, with concavity and calcareous fringe at midline of distal edge. Pereopod I of medium robustness; ventral surface of carpus and propodus with thin setae except for distal robust seta on carpus. Cephalon with pointed lateral lappets. Pereonites 6 and 7 free or fused. Pereonite 2 with robust seta on anterolateral corners. Medial lobes of 3 pleopods I taper distally. Body de- pressed; length roughly 3 times tergal width of pereonite 2.
Type-species.—Nannoniscoides angulatus Hansen, 1916.
Remarks.—Mature or nearly mature ¢¢ may have a more massively developed cephalon than 2° 2 (cf. d and 2 of N. latediffusus [Siebenaller and Hessler, 1977]), and more strongly produced lateral lobes of pereonite 2. There is also some indication
Fic. 13.
Fic. 14. Hebefustis vafer Siebenaller and Hessler, 1977, preparatory 2. A. lateral view; B. dorsal view; C. right antenna I, dorsal view; D. uropods; E. pleon, ventral view (from Siebenaller and Hessler, 1977).
ae = N = / we es _ \ Hanes \ ff Veal \ [ L~ iN
Nannoniscoides biscutatus Siebenaller and Hessler, 1977. A. brooding ° , dorsal view; B. brooding 2 right antenna I; C. brooding 2 operculum (pleopod II); D. posterior margin of operculum (from Siebenaller and Hessler, 1977).
247
248
Fic. 15. Nannonisconus latipleonus Schultz, 1966. A. 3, dorsal view; B. d right antenna I; C. d uropods; D. 3 pleopods I (from Schultz, 1966).
of sexual dimorphism of the first antenna, unique in the Nannoniscidae. There may be differences in the number of aesthetascs and relative lengths of segments 5 and 6 (cf. N. biscutatus [Siebenaller and Hessler, 1977]).
Distribution.—Nannoniscoides angulatus: North Atlantic Ocean, north of the Far- oes, 1284 m (Hansen, 1916); northernmost part of the Kara Sea, 698 m (Gurbunov, 1946); Jorgen Brgnlund Fjord, Greenland, 160-180 m (Just, 1970). Nannoniscoides excavatifrons: northwest Pacific Ocean, in the Kurile-Kamchatka area, 1440-1540 m (Birstein, 1970). Nannoniscoides latediffusus: northwest Atlantic Ocean, equatorial southwest Atlantic Ocean, 587-4833 m (Siebenaller and Hessler, 1977). Nannonis- coides biscutatus: equatorial southwest Atlantic Ocean, 3459-3783 m (Siebenaller and Hessler, 1977). Nannoniscoides coronarius: equatorial southwest Atlantic Ocean, 1493 m (Siebenaller and Hessler, 1977). Nannoniscoides gigas: South Atlantic Ocean, Ar- gentine Basin, 3909-3917 m (Siebenaller and Hessler, 1977). Undescribed material: South Atlantic Ocean, Argentine Basin, 2707 m.
Hebefustis Siebenaller and Hessler, 1977 Figure 14
Synonymy.—Nannoniscus (part), Nannoniscoides (part) (Siebenaller and Hessler, 1977).
Diagnosis.—First antenna 5-segmented, distal segment elongate and somewhat inflated; segment 4 lacks a lateral projection. Pleon with posterolateral spines. Oper- culum (2 pleopod II) ovoid to pear-shaped; distal margin straight, without calcareous fringing margin. Pereopod I of medium robustness; ventral surface of carpus and pro- podus with robust setae. Cephalon with rounded lappets. Male pleopods I widest proxi- mally; sides convex proximally, concave to straight distally. Pereonites 6 and 7 fused medially. Body depressed; length about 3.8 tergal width of pereonite 2.
Type-species.—Hebefustis vafer Siebenaller and Hessler, 1977.
Remarks.—Siebenaller and Hessler (1977) list the species and distinguishing spe- cific characteristics of this genus.
Distribution.—Hebefustis alleni: Bay of Biscay and northeast Atlantic Ocean, 1623-1796 m (Siebenaller and Hessler, 1977). Hebefustis cornutus: northwest Atlantic Ocean, 3753-3806 m (Siebenaller and Hessler, 1977). Hebefustis hexadentium: Argen- tine Basin, South Atlantic Ocean, 5208-5223 m (Siebenaller and Hessler, 1977). He- befustis dispar: southeast Atlantic Ocean, 1427-1643 m (Siebenaller and Hessler, 1977). Hebefustis hirsutus: South Atlantic Ocean, 5024 m (Menzies, 1962). Hebefustis mol-
249
licellus: equatorial South Atlantic Ocean, 943-1007 m (Siebenaller and Hessler, 1977). Hebefustis par: northeast, equatorial, and South Atlantic Ocean, 3459-4435 m (Sie- benaller and Hessler, 1977). Hebefustis primitivus: Caribbean Sea, North Atlantic Ocean, 2868-2875 m (Menzies, 1962). Hebefustis robustus: northwest Pacific Ocean, 5461-5690 m (Birstein, 1963). Hebefustis vafer: equatorial southwest Atlantic Ocean, 587 m.
Nannonisconus Schultz, 1966 Figure 15
Diagnosis.—Pereonite 7 fused medially with pleon. Pleon at widest point wider than cephalon or pereon. Lateral outline of body concave. First antenna 5-segmented,
with bulbous distal article.
Type-species.—Nannonisconus latipleonus Schultz, 1966.
Remarks.—Only 1 species of this genus has been reported in the literature. (How- ever, see Nannoniscus intermedius, new species.)
Distribution.—Southern California Continental Borderland (Redondo Canyon),
465 m.
ACKNOWLEDGMENTS
We thank the heads of the collecting programs who have provided us with mate- rials (see Introduction). This research was supported by grants GA 31344X and DES 74-21506 of the National Science Foundation.
LITERATURE CITED
Birstein, J. A. 1962. Ueber eine neue Art der Gat- tung Austroniscus Vanhoffen (Crustacea, Isopoda, Asellota) aus grossen Tiefen des nord-westlichen Teiles des Stillen Ozeans. Iz- danija Posebna Zavoda Za Ribarstvo NRM, Skopje 3:33-38.
Birstein, J. A. 1963. Deep sea isopod crustaceans of the northwestern Pacific Ocean. Inst. Oceanol., USSR Acad. Sci. Moscow. 214 p.
Birstein, J. A. 1970. New Crustacea Isopoda from the Kurile-Kamchatka Trench area, pp. 308- 356. In Fauna of the Kurile-Kamchatka Trench and its environment, V. G. Bogorov (ed.), Vol. 86. Proc. P. P. Shirshov Inst. Oceanol. Acad. Sci. USSR, Moscow. (English translation: Israel Program for Scientific Translation, Jerusalem, 1972.) *
Gurbunoy, G. P. 1946. Bottom inhabitants of the Siberian shallow water and central parts of the North Polar Sea. Trudy Drej. Eksled. Glavs. Lekok. Paroch. ““G. Sedov’? 1937-1940 3:30- 138. Un Russian).
Gurjanova, E. 1950. K faune ravononogich rakov (Isopoda) Tichogo okeana v. Isopod’ po sbor- am Kamchatskoi morskoi stanstii Gosudarse- vennogo gidrologischskogo in-ta. Akad. Nauk SSSR. Zool. Inst. Issledovaniia dal *nevo- stocknykh morei SSSR 2:281—292.
Hansen, H. J. 1916. Crustacea Malacostraca, III. V. The order Isopoda. Danish Ingolf-Expedi- tion, Copenhagen. 262 p.
Hessler, R. R. 1970. The Desmosomatidae (Isop- oda, Asellota) of the Gay Head-Bermuda Transect. Bull. Scripps Inst. of Oceanog. 15:1-185.
Hessler, R. R., and H. L. Sanders. 1967. Faunal
diversity in the deep sea. Deep-Sea Res. 14:65-78.
Just, J. 1970. Decapoda, Mysidacea, Isopoda and Tanaidacea from Jgrgen Brgnlund Fjord, North Greenland. Meddelelser om Grgnland 184(9): 1-32.
Menzies, R. J. 1962. The isopods of abyssal depths in the Atlantic Ocean. Vema Research Series 1:79—206. Columbia Univ. Press, New York.
Menzies, R. J., and R. Y. George. 1972. Isopod Crustacea of the Peru-Chile Trench. Anton Bruun Rep. 9:1—124.
Menzies, R. J., and J. Pettit. 1956. A new genus and species of marine asellote isopod, Caeci- aniropsis psammophila, from California. Proc. U.S. Nat. Mus. 106:441-446.
Sanders, H. L., and R. R. Hessler. 1969. Ecology of the deep-sea benthos. Science 163:1419- 1424.
Sanders, H. L., R. R. Hessler, and G. R. Hamp- son. 1965. An introduction to the study of deep-sea benthic faunal assemblages along the Gay Head-Bermuda Transect. Deep-Sea Res. 12:845-867.
Sars, G. O. 1870. Nye Dybvandscrustaceer fra Lofoten. Forhandlinger Videnskabers Selskab Kristiana 1869: 145-286.
Sars, G. O. 1897. On some additional Crustacea from the Caspian Sea. Ann. Mus. Zool., Im- perial Acad. Sci., St. Petersbourg 1897:273- 305.
Sars, G. O. 1899. An account of the Crustacea of Norway, II. Isopoda. Bergen Museum. 270 p.
Schultz, G. A. 1966. Submarine canyons of south-
250
ern California. Part 4, Systematics: Isopoda. Allan Hancock Pac. Exped. 27:1—56. Siebenaller, J. F., and R. R. Hessler. 1977. The Nannoniscidae (Isopoda, Asellota): Hebefus- tis n. gen. and Nannoniscoides Hansen. Trans. San Diego Soc. Nat. Hist. 19:17-44. Vanhoffen, E. 1914. Die Isopoden der deutschen Siidpolarexpedition 1901-1903. Deut. Studpo-
lar Exped., 15 (Zoology) 7:447—598. (G. Rei- mer, Berlin).
Wolff, T. 1975. Deep-sea Isopoda from the Carib- bean Sea and the Puerto Rico Trench. Trudy Inst. Okeanol. 100:215—232. (In Russian, sum- mary in English).
Wolff, T. 1976. Utilization of seagrass in the deep sea. Aquatic Bot. 2:161-174.
Siebenaller: Department of Chemistry, D-006, University of California-San Diego, La Jolla, California 92093 USA; and Hessler: Scripps Institution of Oceanography, A-002, University of California-San Diego, La Jolla, California 92093 USA.
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 17 pp. 251-268 7 July 1981
The Higher Taxonomy and Evolution of Decapoda (Crustacea) Martin D. Burkenroad
Abstract. The decapods are herein divided into four suborders: Dendrobranchiata, Euzygida, Eukyphida, and Reptantia. Evidence for monophyly of these taxa is supplied by the adult morphology of characters of gill arrangement, modes of pleopodal incubation, patterns of overlap of abdominal pleura, pleural lock and hinge arrangements, chelation of legs, presence of appendix interna, and form of spermatozoa; the fossil record; and ontogeny. Some possible lines of investigation are outlined which might yield a more natural classification within the Eukyphida and Reptantia.
INTRODUCTION
The difficulty in devising a satisfactory general classification for the Decapoda arises from doubts concerning the higher relationships of the numerous well defined and more or less isolated groups relatively low in the taxonomic hierarchy. For ex- ample, Peneidea, Stenopodidea, and Caridea are regarded by Holthuis (1955) as mem- bers of a supersection Natantia of the suborder Macrura, which he distinguished from two other suborders Anomura and Brachyura. This classification was derived from Bouvier (1917) and Milne-Edwards (1837). The same three ‘‘natant’’ groups (Peneidea, Stenopodidea, and Eucyphidea) are regarded by Balss (1957) as forming the suborder Natantia, while the remaining decapods are grouped together as Reptantia (more or less after Borradaile, 1907; Ortmann, 1892a, 1892b, 1892c; and Boas, 1880). Glaessner (1960), a paleontologist, divides the same three ‘‘natant’’ groups between two different suborders. The Penaeidea and Stenopodidea together with reptant Nephropsidea form a suborder Trichelida, while the Caridea together with the reptant Thalassinidea and Paguridea form an infraorder Anomocarida of the suborder Heterochelida (the other infraorders being Palinura, Anomura, Brachyura, and the Glypheocarida). This is a modification of an earlier scheme proposed by Beurlen and Glaessner (1930). Gurney (1942) also restricted Natantia, placing the Euphausiacea among the Decapoda and the Stenopodidea among the Reptantia. Burkenroad (1963a) divided the natant groups still differently. Peneids and sergestids were placed in the suborder Dendrobranchiata while the Caridea and Stenopodida were placed with the other decapod groups in the sub- order Pleocyemata, an arrangement essentially followed by Glaessner (1969).
The view of this paper is that the Decapoda are monophyletic and distinct from the Euphausiacea, but that most previous subordinal arrangements of the decapods are polyphyletic. It is suggested that the three traditional ‘“‘natant’’ groups are not at all closely related to each other and must be regarded as three independent suborders comparable to the fourth homogeneous suborder, Reptantia. It is further suggested that the Reptantia are naturally divisible into several majdr groups, with the brachyuran forms distinct from all the rest. Within the non-brachyuran Reptantia, thalassinideans seem to be quite distinct from the anomuran, astacuran, and palinuran reptants and are treated in this paper as an independent supersection equal in status to the other three macruran and anomuran supersections.
The presence of chelate legs in the early Triassic reptant Clytiopsis seems to imply that differentiation within the Reptantia by the development of chelae was already then
advanced. Evidence from the structure and development of the living decapods sug- gests a ‘‘hump-backed’’ common ancestor of stenopodids and eukyphids. Eukyphids must have separated from an achelate stem having pleopodal incubation before the development of the definitive branchial characteristics of the Reptantia, in time before the subdivision of the Reptantia was established in early Triassic. Consequently, it seems that at least three main lines of decapods must have been distinct in the Permian. The many striking differences between the living stenopodids and eukyphids suggests that the divergence of these two lines from their common ancestor also may have occurred in the Paleozoic, soon after separation of their stem from the line which then gave rise to the reptants. The formal classification here proposed is as follows:
Order Decapoda Latreille, 1803 Suborder Dendrobranchiata Bate, 1888 Superfamily Peneoidea Rafinesque, 1815 Superfamily Sergestoidea Dana, 1852 Suborder Euzygida nov. Family Stenopodidae Huxley, 1879 Suborder Eukyphida Boas, 1880 Several superfamilies with about 20 living families Suborder Reptantia Boas, 1880 Supersection Thalassinida Boas, 1880 Supersection Astacina H. Milne-Edwards, 1839 Supersection Palinura Borradaile, 1907 Supersection Anomala de Haan, 1841 Supersection Brachyura Boas, 1880
SYSTEMATICS Order Decapoda Latreille, 1803
Diagnosis.—Antennular peduncle with statocyst; maxilla with a large exite which draws respiratory water through the gill chambers; the first three thoracic appendages reduced and modified as mouth parts and the last five specialized as raptorial and walking legs; the exopodites when present taper throughout without an enlarged stalk; gills in three series, of which the distalmost (podobranch) forms part of a coxal exite and is lacking from the fifth thoracic leg (which often bears a pleurobranch); genital apertures coxal. (Exceptions to the above are secondary: statocyst, exopodites, gills and some legs may be lost; and genital aperture may migrate to sternum.)
Suborder Dendrobranchiata Bate, 1888
Diagnosis.—Eggs freely broadcast (or briefly hung from pereiopods as in Lucifer); hatched as nauplii (or protozoeas); pleurobranchs appear later during ontogeny than do the pairs of arthrobranchs, and are lost before the latter, when, during phylogeny, the branchial formula becomes impoverished; gill stems bear a double series of primary rami equipped with secondary filaments or plates; first three pairs of legs chelate, none much enlarged (except the first pair in adult males of Heteropeneus); pleopods without appendix interna (unless such is represented by hooks on endopod of male first pleo- pod, or by the unarmed blade on the male second pleopod of Aristeidae); first pair of pleopods in males with endopod much modified as a copulatory organ (reduced or absent in females); pleura of first pleonic somites overlap those of the second; pleonic somites locked to each other by mid-lateral hinges, which are usually exposed at the two anterior and the two posterior somite articulations but always hidden under the posterior margin of the third somite at the middle articulation (in Recent forms).
Etymology and remarks.—The name of the suborder refers to the compound branching of gills, unique among decapods. It is derived from Bate’s ‘‘Macrura Den-
drobranchiata’’ (1888), although present use applies only to Bate’s ‘‘Dendrobranchiata Normalia’’ (his ‘‘Aberantia’’ comprised the mysids and euphausiids).
It has been traditional to use descriptive names rather than generic derivatives for the higher categories of Decapoda (e.g., Macrura and Brachyura of Latreille; Macrura, Anomura, and Brachyura of H. Milne-Edwards; Brachygnatha, Oxystomata, Anomala, and Carides [although Astacina from Astacus]| of de Haan; Natantia and Reptantia of Boas; Trichobranchiata and Phyllobranchiata of Huxley; Trichelida and Heterochelida of Beurlen and Glaessner). In the case of Dendrobranchiata, desirability of a neutral name at the subordinal level is increased by the likelihood that a new section will have to be created for some of the fossils, Dana’s section name Peneidea being best reserved for the living forms.
The superfamily names are simple promotions of two of Dana’s three families of Peneidea (excluding Stenopus from his Peneidae and transferring Lucifer from his Mysidae to his Sergestidae). The spelling Peneoidea is here used in the view that since Penaeus has been placed on the Official List of Generic Names in Zoology by illegal means (so that the orthographic question remains an open one) Peneus is preferable for both etymological and practical reasons (Burkenroad, 1963)).
Suborder Euzygida nov.
Diagnosis. —Eggs hung from pleopodal setae; hatched as zceas (or later); pleu- robranchs appear before arthrobranchs during individual development, present on five somites when one of the two arthrobranchs per somite is missing in those few adults with an impoverished branchial formula; gill stems bear numerous simple filaments, not arranged in regular rows; three anterior pairs of legs chelate, the third being en- larged; pleopods entirely without appendix interna, first pair uniramous in both sexes; pleura of anterior pleonic somites usually not expanded, but when they are, enlarged enough so the first overlap the second; only the three posterior pleonic somites are hinged together by definite locking points.
Etymology and remarks.—This subordinal name comes from eu-, truly, and zyg- ios, yoked (from Zygia, Juno as the goddess of marriage), which refers to the well- known tendency of members of the group to live in couples even when not imprisoned in sponges (Limbaugh et al., 1961). It also refers to the presumptive Paleozoic con- junction of the group with the yoke-shaped (kyphonid) Eukyphida, from which time it retains a tendency to the bent posture (discussed below). The reasons for a descrip- tive name rather than using Stenopodida for the suborder are similar to those given above for Dendrobranchiata. It may be added that according to Holthuis (1947, 1955), Stenopus might fall prey to Rafinesque’s prior use of the name Byzenus.
Suborder Eukyphida Boas, 1880
Diagnosis. —Eggs hung from pleopodal setae; hatched as zoeas (or later); pleu- robranchs appear earlier than arthrobranchs during individual development; no more than one arthrobranch ever present on a somite and all may be absent even when pleurobranchs are still retained on all the legs; gill stems bear double series of plate- like rami without secondary branches; one or both of the two anterior pairs of legs chelate (except in Procaris), of which one or both of either pair may be enlarged; pleopods usually with appendix interna, the first pair with an endopod (usually reduced; typically not elaborately modified in males); pleura of the second pleonic somite over- lap those of the first; the two anterior and two posterior pleonic somites are hinged together, but the middle articulation lacks a hinge; the pleon is often carried bent between the third and fourth somites (the first maxillipede usually with a setose ex- pansion on the outer side of the base of the exopod, not found in the other suborders).
Etymology and remarks.—This name comes from Ortmann’s modification (1890) of Boas’s (1880) name Eukyphotes, employed by Balss (1927) in Kukenthal and Krum- bach’s Handbuch and (1957) in Bronn’s Tierreich. Boas derives the name from kuphos,
254
crooked (which seems to be cognate with kuphon, a yoke). This usage is preceded in classical antiquity by Aristotle’s, ‘‘. .. ton men karidon ai te kuphai ...”’ in the Historia Animalium (see Thompson, 1910).
Boas made a new name for this group of his suborder Natantia because he felt that to follow Dana in restricting Latreille’s ‘“‘Carides’’ would result in confusion as to what was meant (because of persistent use of Latreille’s name in its original polyphy- letic sense). An analogous reason for now sustaining Boas’s name is that ‘*‘Caridea’”’ in Dana’s sense has of recent years been used chiefly by those who do not recognize the fundamental nature of Boas’s revision and who continue to group long-tailed deca- pods together whether they are reptants or not. A desirable difference in nomenclature, corresponding to the difference in systems of classification, thus results from the pres- ent rejection of ‘‘Caridea’’ as a name for the suborder.
The broad use of karis (which was general, except for Dana, from Aristotle until 1907 when Borradaile revived ‘*‘Carides’’ in Dana’s restricted definition) is appropri- ately preserved in Calman’s Eucarida, and in the term “‘caridoid facies of the Mala- costraca’’ (which does not mean ‘‘eukyphid facies’’ [H. Milne-Edwards, 1837]).
The hump and flexure of the third and fourth pleonic somites, so characteristic of many eukyphids, seems to be the relic of an ancient conjunction of this suborder with the euzygids; and the latter name has accordingly been coined in reference to the former (the roots of both names having apparently originated in the terminology of the cattle yoke).
The Eukyphida contains some twenty more or less distinct living families, the relationships of which are in the main still so debatable that no generally accepted groupings between the subordinal and family levels have yet been proposed. Compare Holthuis (1955) with Balss (1957, who gives a good summary of the distribution of characteristics within the group) and note the remark by the former, p. 10: ‘‘I fully realize that the arrangement of the families given here is by no means a natural one
The mentioned arrangement by Holthuis, including two new superfamilies and several more or less novel regroupings, is only sparsely characterized, discussed, or documented. It does not distinguish between arbitrary groupings by Holthuis, for which there seems nothing favorable to be said, and valid groupings developed by prior authors, e.g., p. 12, ‘*. .. OPLOPHOROIDA .. . Three families are left in this su- perfamily’’; but no reasons are given for retention of Nematocarcinidae when other families traditionally grouped with Hoplophoridae are removed. Of another sort is Holthuis’ statement on p. 82, ‘‘In my opinion the Processidae are so closely related to the Hippolytidae . . . that they cannot be placed in a different superfamily. Both Bor- radaile and Balss assigned the Processidae to the superfamily Crangonoida, but this is certainly incorrect’’; which is a conclusion evidently taken from Lebour (1936), who is not cited. Again, p. 117, °°... Pandaloida . . . consists of the three families Pan- dalidae, Thalassocaridae, and Physetocaridae,’’ but reasons for making Thalassocaris a family are not given, and the somewhat intricate reasons (Burkenroad, 1942) for regarding Physetocaris as a pandaloid are not cited. Holthuis states on p. 36, ‘‘The Bresiliidae generally were believed to belong to the Pasiphaeoida, the Eugonatonotidae and the Disciadidae were placed in the Oplophoroida, while the Rhynchocinetidae
formed part of the Palaemonoida. . . . The Rhynchocinetidae and the Eugonatonotidae certainly are closely related ....The Disciadidae in several respects are interme- diate between the Bresiliidae and the other two subfamilies .. . ’’; but compare this
to Gurney (1939, 1941), Burkenroad (1939), or Lebour (1941), none of which are cited.
In effect, Holthuis seems to have employed only those selected results of others which are compatible with a simplified, artificial arrangement based almost entirely on the structure of the chelate legs (structures actually often intergradient, and apparently highly subject to convergence). His system thus seems unlikely to stand the test of monophyly.
Suborder Reptantia Boas, 1880
Diagnosis.—Eggs hung from pleopodal setae; hatched as zoeas (or later); arthro- branchs and pleurobranchs generally appear simultaneously in development, but pleu- robranchs never occur anterior to the second leg (pleurobranchs seem to appear later than arthrobranchs in ontogeny of thalassinids that have any pleurobranchs, while arthrobranchs appear later than pleurobranchs or are absent on second to fourth legs of Brachyura); gill branches range from multiple filaments (trichobranchs like those in Euzygida) through quadruple or double rows of filaments or flattened, narrow plates, to fully developed phyllobranchs (like those in Eukyphida), but are never secondarily branched as in Dendrobranchiata; number of chelate legs ranges from none to all five pairs (and second and third maxillipedes are also occasionally chelate); first pair of legs enlarged; pleopods with, but more commonly without, appendix interna, first pair uniramous in both sexes and usually reduced, modified, or absent; pleura of second pleonic somite overlap those of first when pleura are sufficiently well developed; all five articulations between pleonic somites locked by mid-lateral hinge points when the pleon is large and strong, but pleon often reduced (the first somite always so) and the pleura often small even when pleon is well developed.
There are characteristics which distinguish most Reptantia from the other deca- pods and are appended here to the standard list above because the wide range among reptants in structure of gill rami, number of chelate legs, form of pleopods, etc., permits only a single completely diagnostic distinction from the other two incubatory suborders (lack of a pleurobranch on the first legs). Body never laterally compressed, too heavy for really effective pleopodal swimming; rostrum never laterally compressed as a ser- rate blade; antennule usually without a stylocerite; antennal exopodite never expanded disto-medially into a foliaceous blade (at least in living forms); basis and ischium of first legs usually immovably joined (as frequently in the other legs also); legs usually stout, with a breaking plane in the basis; propodus usually movable in only one plane; exopods usually entirely absent from the pereiopods (and never more than rudimentary in the adult); podobranchs often present on the third maxillipedes and the anterior four pairs of legs.
Beurlen and Glaessner’s “‘infraorder’. Glypheocarida does not appear to be com- parable with the above five supersections, since distinctions between their Glypheidea and Thalassinidea seem rather obscure, while their Pemphicidea seem to be primitive Palinura (cf. Balss, 1957).
The names and authors here given for higher groups beyond the governance of the Rules are intended as the earliest corresponding to the present definitions. The name Anomala was coined by Latreille but unlike de Haan he excluded the lithodids. Astacini of Latreille was a melange, restricted in Milne-Edwards’s **Famille des Asta- ciens.’’ Eryonids and loricates were first united by Borradaile although Boas recog- nized their close relationship. Brachyura seems not to have been used in exactly the present sense from Latreille on until Boas; similarly, the ‘‘Famille des Thalassiens”’ of Milne-Edwards and the Thalassinidea of Dana included the pagurid Glaucothoe. The name Anomura, introduced by Milne-Edwards for those decapods which establish ‘‘le passage entre les Brachyures et les Macroures ... ,’ has always included the thalassinids or dromiids etc., and it is not equivalent to de Haan’s and Boas’s Anomala either in composition or in connotation. It seems best dropped, along with the com- parable grade-name Macrura Latreille.
DISCUSSION
In this section is given in some detail the reasoning behind the above proposed subdivision of the Decapoda, as based on a consideration of a broad range of decapod biological features.
Evidence from Morphology
Various features which heretofore have been regarded as characteristic of the Reptantia are either not so universal among them or not so limited to them as had been thought. First, a stylocerite is quite as well developed in the Stenopodidae as in the Anomala. Second, a two-hinged articulation of propodus and carpus which is usual in the pereiopods of Reptantia is lacking in the chelipeds of at least some Eryonidea (the chelae in that group being mobile in many directions, as is usual in dendrobranchiates and eukyphidans). Third, the basis and ischium are not fused in any pereiopods in at least some of the axiid Thalassinidea, whereas they are fused in alpheid eukyphidans as an exception to the natant rule. Fourth, the coxal position of the male genital apertures usual in Reptantia (sternal in the higher Brachyura) is matched by stenopod- ids as well as by the eukyphidan Pandalus (Boas, 1880). Fifth, the first pleonic somite is as much reduced in some stenopodids as in some Reptantia. Sixth, the pleopods of some thalassinid Reptantia are almost as well developed and used as much for swim- ming as are those of stenopodids.
Branchial pattern.—Reptantia do possess at least one characteristic unique among decapods which seems to demonstrate the homogeneity of the group and to emphasize its distinctness from the Euzygida, Eukyphida, and Dendrobranchiata. This character is that, in the Reptantia, pleurobranchs never occur on the first pereional somite, even when one occurs on all of the following pereional somites; whereas, in the other three groups, when a pleurobranch is present on the somite of the second leg it is preceded by a homologous gill on the first leg. It is difficult to avoid the conclusion that loss of the first pereional pleurobranch was a basic difference between the ancestral reptant and the ancestral decapod. Table 1 expands on this and compares the various decapod groups. It supplies strong evidence of a monophyletic origin of the Reptantia later in date than the separation of the eukyphid-euzygid line as discussed below.
The extreme formulae given in Table | are synthetic and do not necessarily rep- resent any one species. If any gill is known to be present in any member of a given group, it has been entered in the “‘rich’’ or maximal formula; similarly, if any gill is known to be absent in any species which retains any gills, it has been omitted in the ‘‘impoverished’’ formula. For example, a dorsal arthrobranch of the second maxil- lipede is present in laomediid thalassinids, which lack pleurobranchs; whereas, in the axiid thalassinids, some of which have pleurobranchs, the dorsal arthrobranch of the second maxillipede is absent. In the maximal formula given here for thalassinids both the dorsal arthrobranch of the second maxillipede and the pleurobranchs are shown. Intermediate formulae are selected actual ones. However, it should be noted that relatively few branchial formulae have been determined; therefore, all statements con- cerning them should be understood as qualified by the phrase ‘‘as far as known.”
The specific branchial formulae from which the present table has been prepared are given in compilations by Calman (1909), Gurney (1942) and Balss (1957), in part corrected or confirmed by my own published and unpublished observations. The prin- ciples employed in identifying those gills which are present on somites where the full complement is lacking are as follows: the podobranchs spring from (or at the base of) a stem, the epipodite, which has a coxal insertion, and which is often present without bearing branchial filaments; the arthrobranchs, primitively in pairs from narrowly sep- arated insertions, spring from the body wall above the coxa and sometimes originate in larval development by the splitting of an unpaired rudiment (Burkenroad, 1945), with the posterior one of the pair usually quite appreciably dorsal to the ventral one and near the posterior margin of the somite; the pleurobranchs are never paired, and insert on the body wall above the arthrobranchs, near the anterior margin of the somite. When there are only two body gills on a somite, the homology of the dorsal-most has to be judged chiefly by its position anterior or posterior to the ventral one. Although the lack of three body gills on any somite of Eukyphida prevents complete certainty that the dorsal one is a pleurobranch, it seems likely from the euzygid pattern that the rule of position is applicable also to eukyphids.
Maximal, intermediate and impoverished branchial formulae among the living decapod Crustacea. (r) rudimentary, (0) absence, (e)
epipodite, (p) podobranch, (a) arthrobranch, (pl) pleurobranch.
TABLE I.
a
Thoracic somite
Pereiopod
Maxillipede
5
3
len |
foe)
a
Limb
a
a
a
a pl e+p
Sar jo BW? sey) Bl joll Fe jo
Branchial class
1+0
al
a
lon
1
1
It
Dendrobranchiata 1 + 0
0 0 4 #17
lt+r
l
1
l
1
lar 0) 0) 0 Wer
1+0 0 1+0 0 1+ 0
N
ft © O40 OOF ON 0
0 0+0
1 1 1
0 0+0 1
l ] ] 1
r
1
19 13
11
1+ 0 0+ 0 0+ 0
a
1
1 if 0
1 i
Euzygida
(oe)
1
1 I
0+ 0 0+ 0
l
|
1 l
0+ 0 0+ 0
| 1
0+ 0 0+ 0
1 l 1
1+ 0 0
0 0
0 0
Il+r
1+ 0
foe)
r
]
1+ 0
l+r 1+ 1
1 O80 ae) hse 0) 0
1+ 0 0+ 0 0+ 0
1+ 0
0+ 0
haa) 0.+ 0
eae OY Oar WW Wer OOO) Ws20)
Eukyphida
0
1 l
r 0
1 l
r 0
0+ 0
0+ 0
l 1
0
l¢+r
la @ @
0+ 0
ll ae 1
lon |
a
lap il
Homarida
AN
AN
aN
il ap 1
1
il a= 0
1+0 0 r+0 0 1+ 0
0) -@ 7 As
l¢+r
ae I
1+ 11+r0
hap i il sp re ©
0
() Her dt il
r
lanl
oe
la il
N
a
1+ 1
I
0 0
Palinura
19
a
lon |
a
NX
0
ANQNINANN
1+ 1 0+ 0
1 1 0
AIN
5 5
0 0+0
ANIANN
sell
0 0 0 (
OMe 0 0) 0)
1 2 2 2
r+ 0
1+0 00+0 0 0 1 1+1 0 0
0 1+0 0 0 040 r+0 0 O
1+ 0 Is- 0) 0)
0+ 0
Thalassinida
vnueiday
14
\|N
ie
1+ 0 1+ 0 il +e (0)
It se O
1+0 0
Anomala
0+ 0
1
a
0
2
1
0
1+0 00+0 0 0
10
2 0) O20 2
0 04+0
Nae) 0) Wart) 0) 0 WS (0)
1+0 0 1+0 0 1+ 0
fom)
0) 0
0
0+ 0 0+ 0
l 0
Co ==)
1+ 1 0+ 0
0 0+0
1+ 1 0+ 0
aI
eal 0+0
lop i ge Il
Brachyura
l
0 0
0
5
0
5
ORNs 20 Oi nO eal
0
0
foe)
lo |
0
0
0
X () War 0)
0 0+0
) @) te)
25,
Hypothetical
eel
Stem-decapod
When there is only one body gill (as always on the first maxillipede and fifth leg) its homology is uncertain. Since the gill of the fifth leg appears after the arthrobranchs of preceding somites in Dendrobranchiata (like the pleurobranchs in this group), and before the arthrobranchs in the Euzygida and Eukyphida (like the pleurobranchs in these groups), I have called it a pleurobranch throughout the Decapoda. There is no reason to think that the body gill of the first maxillipede is not homologous in all decapods, but to call it an arthrobranch is a convention. It should be noted that this gill is a lamella fringed with filaments in Dendrobranchiata (the filaments tend to be separated into two groups in Solenocerinae, but this probably does not mean that they represent two distinct gills as thought by Kubo [1949] whose observations on branchiae seem erratic). In contrast, in the euzygidan Stenopus cf. S. scutellatus the gill of the first maxillipede is an ordinary one of large size (as well developed as that of the second maxillipede); and the gill of the first maxillipede is also normal in form, though minute, in the laomediid reptant Axianassa sp.
There are two body gills on the second maxillipede in many Dendrobranchiata and in reptant laomediid Thalassinida, but none elsewhere in the order. Holthuis (1947) has mistaken the gill of the first maxillipede of Euzygida for a second one on the second maxillipede, except in Spongicoloides profundus for which he evidently copied the correct formula from Hansen. There may be a real difference between Dendrobran- chiata and Reptantia in homology of the dorsal of these two gills. The dorsal gill in Dendrobranchiata is clearly anterior to the ventral one, which inserts on the posterior margin of the somite. In Axianassa sp., the dorsal gill is directly above the ventral one. which is in the middle of the somewhat roomier lower part of the narrow somite. The dorsal gill appears to be the one missing in Euzygida, according to the low and medial emplacement of the one which is present.
The dorsal of the two body gills of the third maxillipede of Eukyphida has been termed an arthrobranch by some observers, a pleurobranch by others. Its position seems to be anterior to the ventral gill in all, so it is here considered a pleurobranch since in Burkenroad (1939) ‘‘somite VIII’ is a lapsus calami for somite IX.
Gills absent in the adult seem never to be present in the larvae, although it is important to note that gills relatively weak in the earlier larva sometimes outgrow their previously larger neighbors (Burkenroad, 1945). In general, gills absent in adults with impoverished formulae are relatively delayed in the larval development of related forms with rich adult formulae (Burkenroad, 1934, 1939, and 1945).
It is most important to note the following. Inasmuch as any body gill on a somite can presumably serve the function of another, the differences among decapods in patterns of loss of gills from the primitive, maximal formula seem likely to be controlled chiefly by genetic accident in ancestral forms and not to be much subject to adaptive convergence. There are several significant features to be derived from Table 1. First, there is the tendency of dendrobranchiates to lose pleurobranchs in contrast to the preferential loss of arthrobranchs in euzygids and eukyphids. Second, there is the persistence of a podobranch on the first maxillipede and the fourth leg in some Rep- tantia (Calman, 1909, p. 278). Third, there is the total lack of pleurobranchs anterior to the second leg in any reptant (although pleurobranchs are present on the second and following legs in some members of all reptant supersections). Fourth, there is a total lack of podobranchs in all Anomala. Fifth, there is the total loss of arthrobranchs posterior to the first legs in all but the most primitive Brachyura despite the retention of pleurobranchs on posterior somites in most of the higher Brachyura. Any natural evolutionary system of decapod classification must give serious consideration to these features.
One conclusion that can be reached is that the gills of living Dendrobranchiata and Reptantia cannot be derived one from the other but only from a common ancestor with a richer formula than in any living form. That is, no dendrobranchiate has a podobranch on the first maxillipede or the fourth leg, and no reptant has a pleurobranch on the maxillipedes or the first pereiopods. Similarly, the branchial pattern in Brachyura can- not be derived from one like that in any living Anomala, since a podobranch is present
on at least one of the pairs of maxillipedes of some member of every brachyuran group. Therefore, it seems doubtful whether the podobranch-bearing ancestor of the Brachy- ura could be defined as an anomalan.
Pleopodal incubation.—The basic reason against accepting Boas’s **Natantia”’ as a natural group is that it would require that pleopodal incubation of the eggs arose independently in at least two different decapod lines. The condition in the Dendro- branchiata, where the eggs are broadcast (or by exception briefly incubated under the thorax), must be regarded as a primitive characteristic correlated with eclosion in the naupliar (or by exception, the protozoeal) state, and almost certainly retained from the ancestral decapod. Therefore, if the dendrobranchiates, euzygids, and eukyphids had a common ‘‘natant’’ ancestor distinct from that of Reptantia, the euzygids and euky- phids must have invented pleopodal incubation and abbreviated development indepen- dently of the reptants—which is possible but seems improbable.
As shown by Burkenroad (1947), incubation in decapods is made possible by the temporary self-fusibility of the outermost of the three membranes secreted by the ovum. Essentially, the eggs can become attached to any structure around which their outer shells can meet to fuse. Although an enzymatic intensifier from pleopodal glands seems usually involved in the process, incubation appears to be more an invention in behavior—retention of the eggs in contact around suitable projections until the outer membranes have fused and hardened, together with an inhibition of subsequent clean- ing behavior—than in structure.
Attachment of the eggs of the sergestoid dendrobranchiate Lucifer to spinules on the coxa of the third leg shows that the independent development of incubatory be- havior can occur. It would, however, be surprising if the euzygids, eukyphids, and reptants had each independently developed not only behavior leading to egg attach- ment, but also egg attachment exclusively to special pleopodal setae. It is therefore probable that euzygids, eukyphids, and reptants had a common ancestor which di- verged from the dendrobranchiates by developing pleopodal incubation. Pleopodal in- cubation made abbreviation of development possible by reducing larval mortality, thus permitting fewer and larger eggs. Abbreviated development facilitates change in the form and order of appearance of various structures since the embryonic structures no longer have to be functional as they were with naupliar eclosion, which characterized the decapod stem form and the Dendrobranchiata. Therefore, the development of pleo- podal incubation may have been the crucial step that freed decapod evolution from the limitations of the caridoid facies.
Overlap direction of abdominal pleura.—Euzygida resemble Dendrobranchiata in having the first pleonic pleura overlapping the second. Eukyphida resemble Reptantia in that, when any overlap is detectable, the second pleuron overlaps the first (compare Crangon with the undoubtedly convergent Naushonia). It seems likely that the deca- pod stem form had unexpanded pleura with no decided overlap, as in many living Reptantia. However, the fact that the pleural overlap in reptants (when detectable) seems always to be of the second pleuron over the first suggests that the pleura of living Reptantia may have been reduced from an ancestral state of greater expansion and decided overlap. It is my view that the direction of overlap must have been variable in the common ancestor of the euzygids and eukyphids. The resemblance in pleural overlap of euzygids to dendrobranchiates and of eukyphids to reptants is, then, the result of independent development. If the directions of overlap were not independently derived, this would imply independent development of the peculiar euzygid-eukyphid branchial pattern and a multiple origin of pleopodal incubation (among other features), which seems unlikely.
Pleural lock and hinge arrangements.—In addition to the direction of overlap of the pleura, their contacts supply another distinctive set of patterns among the deca- pods. Euzygids are unique in having the anterior three pleonic segments more or less loosely and flexibly bound together, with a locking point present only between the fourth and fifth, and fifth and sixth somites. Reptants with well-developed pleura have, in contrast, all of the segments locked together by mid-lateral hinge points.
260
These reptant hinge points are exposed and strong in eryonids, scyllarids, and some homarids. They are present in Cambarus, but hidden under the pleura except between the fifth and sixth somites. They are present but hidden except between the first and second somites in Upogebia. They are exposed on all segments in Munidopsis but weak between the fifth and sixth somites. In raninids they grow stronger from front to rear.
Eukyphids have a still different pattern. In those I have examined there is no well- defined hinge point between the third and fourth somites. These somites are quite flexibly coupled although bound rather firmly in, e.g., Spirontocaris. The other pleonic somites are locked to each other, with all four pairs of hinges usually externally visible. The one between the second and third somites is sometimes weak and hidden under the pleura (e.g., in Spirontocaris).
Finally, the dendrobranchiates resemble the eukyphids in having well-developed hinges at the anterior two and posterior two pleonic joints. These hinges are externally visible except the anterior two in Sicyonia which are hidden under the pleura. No hinge is externally visible between the third and fourth somites. The dendrobranchiates differ from the eukyphids in having the third and fourth somites quite inflexibly coupled by a rather ill-defined hinge point hidden under the pleura.
It seems possible that the decapod stem form may have had all pleonic somites obviously hinged and that a tendency towards loss of pleonic hinges was a special characteristic of the hypothetical euzygid-eukyphid line. At any rate, it seems signifi- cant that the euzygids, although resembling the dendrobranchiates in direction of pleon- ic overlap, are far different in pleonic hinge pattern.
Pleonic hinge patterns can be observed in fossils. In Aeger, an available specimen of A. tipularius from Solenhofen shows the dendrobranchiate pattern including the covered locking-point in the joint between the third and fourth somites. It is also noted that the figures of Acanthochirus and Dusa by Balss (1922) suggest an exposed hinge in this position such as now occurs only in Reptantia.
Branchial development.—A fundamental feature in which the euzygids resemble the eukyphids, and the reptants resemble the dendrobranchiates, has been described by Burkenroad (1939). In the course of euzygid and eukyphid ontogeny pleurobranchs appear before arthrobranchs. When the gill formula of their thoracic somites three to seven (second maxillipede to fourth leg) is impoverished in an adult, it is one or both of the pair of arthrobranchs which is missing rather than the pleurobranchs, e.g., some species of the euzygids (Spongicoloides [Holthuis, 1947]) and in all Eukyphida. In contrast, in peneids and axiid reptants the pleurobranchs appear later in development than the arthrobranchs (Gurney, 1942). In adult peneids and reptants, pleurobranchs may be absent on thoracic segments three to seven even though paired arthrobranchs are present on all of them. The higher Brachyura, with greatly impoverished branchial formulae, differ from other reptants in that pleurobranchs may occur on the somites of the second and third legs although arthrobranchs are completely lacking there. It seems possible that the euzygids and the eukyphids had a remote common ancestor distinguished from the stem leading to the reptants by the precocious appearance of larval pleurobranchs.
Chelate legs and appendix interna.—The euzygids share with the dendrobran- chiate and the astacuran reptants the characteristic of having chelae on the three an- terior pairs of thoracic limbs, and with the dendrobranchiates the lack of the appendix interna. These similarities are probably not phylogenetically significant since the sim- ilarity to reptants in these same features has almost certainly not been the result of retention from a common ancestor. Likewise, certain thalassinids resemble eukyphids in possessing two pairs of chelate legs and sometimes the appendix interna, and this also seems unlikely to signify any special relationship.
The appendix interna is assuredly a primitive character, independently lost in a variety of groups (note its retention on the second male pleopod of aristeid peneoids and the astacine genus Enoplometopus [Barnard, 1950)]).
261
The unknown ancestor of the decapods may have had no chelae at all, as in males of the living scyllarid Palinura. However, unless the decapod stem form had the pos- terior maxillipede and all five pairs of legs chelate, so that the differing patterns in various groups all represent reduction of the ancestral number, there must have been some independent development of chelae among decapods.
Spermatozoan construction.—Similarity of spermatozoa among “‘Natantia’’ has been cited as evidence of the unity of such a group by Balss (1957, p. 1515; *“Die Natantia z. B. stimmen in Bau der Spermien tiberein. . . .”’). This supposed uniformity does not in fact exist. There is as great a variation in gross form and structure among Dendrobranchiata as among Reptantia—from superficially simple ellipsoids in the ser- gestid Lucifer faxoni (comparable with the reptant Callianassa seilacheri) to subdi- vided cells with a seta-like, obliquely directed appendage in the peneoid Trachypeneus birdi (apparently comparable in complexity with the structure in such reptants as Pa- gurus longicarpus). In some dendrobranchiates (e.g., Parapeneus longirostris, Hymenopeneus robustus) the spermatozoa do show a resemblance in general form to those of some eukyphids, a more or less flattened head and a tapering central spike like a tack. However, there is no reason to think that these cells are any more like each other cytologically than they are like reptant spermatozoa. The tack-like form is not universal in eukyphids (there are exceptions such as Xiphocaris elongata and Atya scabra). Finally, the euzygids have still another type of spermatozoan according to my examination of unstained material from the jelly-column in the vas deferens of a for- malin-fixed, alcohol-preserved male of Stenopus cf. S. scutellus (apparently the first spermatozoan from this group to be described). This cell is superficially like the dia- gram of a “‘Squilla’’ spermatozoan given by Nichols (1909). It is a slightly flattened spheroid, apparently lacking appendages, with a small refractile body in the middle of one side of the disc.
Before the various types of decapod spermatozoa can be interpreted in terms of relationship at the subordinal level, it will be necessary to have electron microscope studies of a variety of them, like those of Moses (196la, 19615) on Procambarus clarki. It would also be helpful to understand the functional significance of the differences in structure (see Burkenroad [1947] on the mechanism of fertilization in decapods). De- spite the difficulty of interpretation of gross structure, the decapod spermatozoa might be of considerable use in distinguishing taxa. Burkenroad (1934, 1936) made routine descriptions intended as notes toward possible future use in setting generic limits.
Evidence from the Fossil Record
Not having examined much fossil material, I am not in a position to discuss with authority the compatibility of the fossil record with the foregoing hypotheses, but will venture a few remarks. Triassic dendrobranchiates include a form quite indistinguish- able from the living Peneus—Anitrimpos, known back to the lower Triassic (Burken- road, 1936; Balss, 1922, 1957). There is also an extinct type perhaps representing the common ancestor of Peneoidea and Sergestoidea—Aeger (Burkenroad, 1936, 1945; Balss, 1957), which has a petasma which would ensure that it is not a euzygid.
Reptantia of the groups Astacina and Palinura Eryonidae, already with chelae like those of living members of these groups, were also present in the Triassic (Glaessner, 1969). Also known from the Triassic are the Glypheidae, without chelae and somewhat suggesting thalassinids, and the Pemphicidae, which suggest scyllarid Palinura but with rostrum, diaeresis, and rudimentary chelae on the second and third legs. The Gly- pheidae seem to have survived into the Recent without developing chelae. Thalassin- ida, Anomala, and Brachyura have not yet been found before the Jurassic. The Jurassic Anomala, however, included both pagurid and galatheid forms, implying that this supersection must have separated long before from the others. The earliest decapod, Palaeopalaemon newberryi from the Late Devonian, cannot be assigned with confi- dence to ‘‘any of the recognized infraorders’’ (Schram et al., 1978).
262
Eukyphida also have not yet been found before the Jurassic. Adorella is of special interest as apparently lacking chelae, all of the legs being subchelate with the dactyls folded against the body of the propodus (Balss, 1957).
Euzygidan fossils have not so far been recognized. However, the supposed den- drobranchiate Acanthochirana (Jurassic) evidently had the first pleonic somite rather reduced, the pleura narrow and spiny and the uropodal exopod lacking a diaeresis (Balss, 1922); thus it might be a euzygid.
Glaessner (1960) believes that Glypheidae gave rise to the Pemphicidae and to all of the extant reptant groups except the Astacina. He derives the Astacina separately with the dendrobranchiates and euzygids. However, he does not discuss the surprising similarity of the carapace of his stem astacine, Lissocardia, to that of the glypheids. In my judgement, a glypheid-like stem form, lightly built and without hypertrophied first legs, gave rise to all the reptant supersections. This would seem to imply that, despite its great age, Palaeopalaemon may be well advanced along the reptant line. It will have differentiated before the Late Devonian from a similarly achelate euzygid- eukyphid stem-form with large first pleonic somite, both of these being distinct from a dendrobranchiate stem-form already with chelae. Although the lack of fossils of higher Brachyura before the Cretaceous seems highly significant, the lack of early specimens of the lightly constructed and probably rather scarce eukyphids and euzyg- ids need not be surprising. Fossils now being laid down in warm seas are probably also mostly heavily armored reptants, though in the modern fauna these may be fewer than the dendrobranchiates (the eukyphids and especially euzygids being sparser still).
Evidence from Ontogeny
Gurney’s valuable but rather disappointing summary (1942) of knowledge of the larvae of the Eucarida does not attempt ‘‘to define the larval characters of the major groups.’ However, it does offer a brief estimate of certain relationships on p. 11-12, some further remarks and a table of characteristics helpful ‘‘in placing a larva”’ on p. 177-179, and a summary of the characteristics of caridean larvae on p. 192-193. Gurney indicates that ‘‘the primitive larval history which characterizes all Penaeidea distin- guishes the group sharply from all others’’ among the decapods; that the larvae of Stenopodidea ‘‘are very peculiar, but suggest some relationship to the Anomura and Thalassinidea’’; that the Eukyphida show a peculiar resemblance to the protozoea of dendrobranchiates in having only 6 pairs of spines on the embryonic telson; and that larval Reptantia are peculiar in having the antennal scale unsegmented, as well as in never having an exopod on the maxillule (indicated as present in all Dendrobranchiata and in a few Eukyphida and Euzygida). Gurney’s chief reason for relating the Euzygida to the Reptantia is the hair-like form of the second spine of their telson, but on p. 239 he notes that ‘‘the possession of so primitive a maxillule in one species is difficult to reconcile with such a view.”’ On p. 146-147 he seems to doubt the significance of the peculiar difference of euzygids and eukyphids from dendrobranchiates in order of de- velopment of the gills, and suggests that instead ‘‘the dorsal gills of Caridea may actually be arthrobranchs of the dorsal series.’ However, it must be noted that, what- ever the homology of the dorsal gill of eukyphids, there is a real resemblance to euzygid development, and a real difference from dendrobranchiates (Burkenroad, 1945).
Gurney’s (1942) pessimistic feeling that, ‘‘It must be confessed that the evidence from development so far accumulated has not produced any very serious contribution to the systematics of the group,’’ seems to me simply a result of the natural reluctance of systematists to attempt to organize the mass of specialized information, difficult to check or extend, which has become available about the larvae; I should like to ac- knowledge here that the present revision of the Decapoda stems from an early collision with that stimulating work of Gurney, and to note again that the revision is directly dependent on the lead supplied by the peculiarities of branchial ontogenesis.
A larval pattern, the possible large scale significance of which has not been pre- viously considered, is provided by the order of development of the pleopods. The first
263
pleonic somite of the reptant larvae never has pleopods until long after those of pos- terior somites are well developed and biramous (indeed, never until after metamor- phosis, if then, except in eryonids). In euzygids the first pleopod ‘“‘seems generally if not always to be delayed in appearance till the end of larval life’? (Gurney, 1942). In eukyphids, all five pleopods usually appear together, but according to Gurney’s ac- count (1941) of Rhynchocinetes the first pleopod in it seems to be somewhat delayed after those of 2—5; and the first pleopod does not appear until post-larval stages in Leptochela (Gurney, 1938). In dendrobranchiates, the pleopods usually appear all to- gether, but (in contrast to the incubatory groups) when the appearance Is serial it is the anterior most pleopod which first develops (Gennadas) or is the best developed (Acetes). In this tendency to precociousness of the first pleopod, the dendrobranchiates seem to make some approach to the serial development found in euphaustids; and it seems possible that in the evolution of the incubatory decapods there was a more or less progressive tendency to increased delay of the first pair of pleopods.
Another larval feature, the possible phylogenetic significance of which has not been previously noticed, is the tendency for the pleon to be “‘bent at the third segment at almost a right angle’’ in the late larvae of euzygids (Lebour, 1941). This posture resembles that of eukyphid larvae and seems correlatable with the lack of a hinge between third and fourth somites in adults of both groups, since it does not seem to be found in other decapod larvae. It seems likely to have characterized the larvae if not the adults of the common ancestor of Euzygida and Eukyphida.
The hair-like second telson spine in larvae of Euzygida, Thalassinida, Anomala, and Dromiacea (and probably some Astacina: note that Gurney’s remark in 1942, p. 227, that the telson is ‘‘normal for this stage’’ in his possible Nephrops from the Great Barrier Reef is quite different from his remark in 1938, p. 296, ‘‘The telson, indeed, is exactly the same as that of Callianassa . . .”’) seems to be a character of considerable significance, as Gurney thought. Rather than a mark of special relationship between euzygids and thalassinids, or dromiids and Anomala, however, it seems more likely to be a relic from the stem-form of the three incubatory suborders, never present in dendrobranchiates, and effaced in eukyphids, most Astacina, Palinura and the higher Brachyura.
A more thorough review of decapod development from a phylogenetic outlook might be fruitful.
Taxonomic Issues
In both the Eukyphida and the Reptantia there is a large number of more or less clearly distinguished living groups, the interrelationships of which are still poorly understood. I am not fully prepared to attempt a definitive arrangement of either of these two suborders, but will offer scattered remarks based on new but incomplete observations. :
A) Among Eukyphida, the male genital aperture is in the articular membranes and definitely proximal to the coxa in a number of Palaemonidae (including Pontoni- inae) and Alpheidae which I have examined. It is coxal in all others so far checked (several Hippolytidae, Atyidae, Hoplophoridae, Pandalidae, and Crangonidae). This coxal position is rather different from the coxal aperture in Stenopus and various Reptantia, being low on the segment instead of in the distal part. I believe the articular apertures probably indicate a close relationship (as concluded by Gurney from embry- ological evidence). This evidence would suggest that Holthuis’s (1955) superfamilies overemphasize the relative dimensions of the chelate legs.
B) Like other authors after Borradaile (1907), Balss (1957) has stated, that in the Reptantia ‘‘der Stylocerit fehlt immer . . . ..” However, later in that same work Balss says of the Eryonidea Palinura, ‘‘Antennula . .. manchmal mit Stylocerit.’’ The basal joint of the antennule of Polycheles typhlops bears a pair of spines which may or may not be homologous with the stylocerite of dendrobranchiates, eukyphids, and euzygids. These resemble those of the galatheoid Munidopsis and pagurids in form and relation
264
to the statocyst. The galatheoid Petrolisthes has the statocyst expanded into a lateral projection of the base of the antennule which seems likely to be a homologue of the ‘‘natant’’ stylocerite. The hippid Lepidopa is comparable. The eryonids, then, prob- ably do retain a stylocerite lost in the scyllarids.
The eryonids seem to differ from the scyllarids (Loricata) in a number of other features which seem of importance (as far as can be judged from my comparison of Polycheles typhlops with Panulirus argus). The eryonids have a less completely fused basis and ischium of the legs (Barnard, 1950; Balss, 1957). They lack a double hinge between carpus and propodus of the legs. They have chelae on the anterior four legs (Balss), and the base of the antenna is not fused to the carapace and epistome but is free. The fusion of carapace and epistome is concealed under the frons and visible only inside the branchial chamber as in homarids. Borradaile (1907) and subsequent authors are thus in error in distinguishing the eryonids as well as the scyllarids from the Astacina by “‘carapace fused at sides with epistome.’’ The scyllarids are inter- mediate between eryonids and Astacina in grade of loss of appendix interna, which is present on the male second pleopod of Enoplometopus, which appears to be an asta- cine (Barnard, 1950). The living eryonids resemble the scyllarids and differ from the astacines in lacking a diaeresis on the uropodal exopod, but some fossil eryonids had a diaeresis (Balss, 1957). The loss must have occurred independently in the chelate and the achelate lines, unless the latter branched off from the eryonids and lost the chelae (which seems less likely than that the scyllarids stemmed from achelate pem- phicids). In fact, it is not easy to define Borradaile’s *‘Palinura’’ with precision except by their possession of a peculiar button fastening the carapace to the side of the last thoracic somite (presumably it necessitates special arrangements at the molt and there- fore seems of considerable phylogenetic interest). The eryonids and scyllarids may not have had a common ancestor since the early Triassic (if the pemphicids were, as seems possible, ancestral to the scyllarid stem rather than to that of all Palinura).
C) The ‘‘Anomura”’ are said by Borradaile (1907) and subsequent authors to have ‘‘Carapace not fused with epistome.’’ However, this is quite untrue of Calli- anassa and Upogebia, where the frons above the linea thalassinica is openly fused with an extension of the sternite behind the antenna. A similar fusion in some axiids at least seems to be indicated by Bouvier’s remark (1925) that in Calocaris aberrans ‘*Le bord anterieur de la carapace . . . au dessous des antennes . . . est fusionné avec l’epistome’’; and this is probably also true of the laomediid Naushonia, according to Chace’s figure (1939) of it.
The frons in other ‘**Anomura’”’ (the Anomala) is somewhat different, the fusion of carapace and epistome being shallowly concealed (Chace, 1939, Fig. 6a, b, c, d); and this, together with the presence of a stylocerite would seem to distinguish the Anomala as a unit from the Thalassinida. Gurney (1942) believes that the thalassinids are not homogeneous but include two groups, one (Axiidae and Callianassidae) shown by its development to be homarid in relationship and the other (Laomediidae and Upogebiidae) related to the Anomala. However, Gurney ultimately found the larval distinctions to be less absolute than he at first believed, and it is difficult to believe that the peculiar frons of Callianassa and Upogebia was independently invented (al- though it then seems surprising that in thalassinid larvae the frons is produced to conceal the point of fusion). It would be of great interest to know whether an exposed fusion of carapace with epistome might be combined with presence of a stylocerite in the glypheids.
D) The loss of arthrobranchs from pleurobranch-bearing thoracic somites pos- terior to the fourth is highly distinctive of Brachyura with a reduced gill complement. It therefore seems likely that there was a brachyuran stem form with a more or less complete branchial formula and coxal genital apertures which was distinguished from other reptant lines by delayed appearance of posterior arthrobranchs (relative to pos- terior pleurobranchs) during individual development. Although it is not completely certain that the dromiids qualify as true Brachyura by delayed development of the posterior arthrobranchs, this seems probable from Gurney’s account (1924) of the gills
Fic. 1. Cladogram of relationships of decapod suborders postulated in this paper. Reptant groups not arranged phylogenetically. Numbers and letters keyed to text. Parentheses indicate lack of the particular advanced character in important members of that group.
of what Lebour (1934) agrees must be a Dromia. Gurney describes the third zoea as having the paired arthrobranchs already present on thoracic somites 3 and 4, while unpaired rudiments occur on ‘‘each of the following limbs.”’ In the fourth zoea, there are pleurobranchs on each of the legs 2-5, and an unpaired arthrobranch has appeared on legs 2-4. In Lebour’s fifth zoea, the adult complement has been completed by the addition of a second arthrobranch on legs 2 and 3. It thus seems that the gills on legs 2-5 in Gurney’s third zoea were pleurobranchs, and that Dromia possesses the de- velopmental pattern to be expected of the brachyuran stem form. The combination in Dromia of unique larval characteristics and brachyuran features with others found in thalassinids and in Anomala (which Lebour thinks make it necessary to “‘remove the Dromiacea from the Brachyura’’ to ‘‘a separate group’’) seems likely to result from the retention of larval characteristics from the common reptant stem in this surviving representative of the primitive Brachyura.
E) The possibility that the linea ‘‘thalassinica,”’ ‘‘anomurica,”’ “‘dromidica,’” and ‘“‘homolica’’ are homologous and retained from a common ancestor rather than, as suggested by Glaessner (1960), acquired independently in different lineages, is of con- siderable interest (Burkenroad, 1963a). This is especially so since the Late Devonian Palaeopalaemon seems to possess a linea.
99 66
CONCLUSIONS
A diagram showing the presumptive order of appearance of the characteristics of the suborders of Decapoda, up to the differentiation of the supersections of Reptantia
266
in the Triassic, is presented in Figure 1. Changes from a hypothetical ancestor are shown at each branching of the lines by code numbers which are explained in the chart below, primitive characteristics being retained except as indicated. (In some of the ultimate branches, characteristics different from those shown in their hypothetical stems have since appeared.)
DECAPOD CHARACTERISTICS (see Fig. 1)
Primitive Advanced
1. Eggs set free; eclosion naupliar. 1A. Pleopodal incubation; development abbreviat-
ed.
2. Thoracic somites 3-7 each with a podobranch- 2A. Pleurobranchs delayed. bearing epipodite, two arthrobranchs and a 2B. Arthrobranchs delayed. pleurobranch, which appear more or less si- 2C. Anterior pleurobranchs omitted. multaneously during individual development. 2D. Posterior arthrobranchs delayed.
3. First pleonic somite large; first and second pleu- 3A. First pleura expanded and overlapping the sec- ra not expanded enough to overlap; all pleonic ond; hinge between third and fourth pleomeres somites hinged together by an exposed diar- covered. throsis. 3B. First somite reduced; second pleura slightly ex-
panded to overlap the first.
3C. First somite somewhat reduced; its pleura somewhat expanded and overlapping the sec- ond; hinge between third and fourth pleomeres lost.
3D. Second pleura expanded to overlap the first; hinge between third and fourth pleomeres lost.
4. All pleopods large, biramous and with an ap- 4A. Appendix interna lost except traces in male first pendix interna which couples each pair togeth- and second pleopod. er. 4B. First pleopods reduced and uniramous; appen-
dix interna on the rest.
4C. First pleopods more or less reduced: unira- mous; no appendix interna.
4D. First pleopod with endopod usually reduced, appendix interna on all pleopods usually.
5. Legs with propodus movable in more than one 5A. Carpal-propodal joint with two hinges, restrict- plane; all seven joints free. ing propodus to movement in a single plane.
6. Trichobranchiae. 6A. Dendrobranchiae.
7. Legs not chelate. 7A. First three pairs chelate.
7B. First four pairs chelate. 7C. First pair chelate.
8. Diaeresis on uropodal exopod. 8A. No diaeresis.
9. Antennular stylocerite present. 9A. No stylocerite.
10. Attachment of carapace to anterior sternite (epi- | 10A. Fusion of carapace to epistome exposed. stome) hidden under the produced frontal mar- gin.
11. Pleon large and extended. 11A. Pleon reduced.
12. Carapace not fastened down posteroventrally 12A. Posteroventral sides of carapace held in place (unless by overlap of anterior margin of first by a projection of the last thoracic pleura which pleonic pleuron). engages inner side of carapace.
ACKNOWLEDGMENTS
In doing the work on which this paper is based, I received important help from those whose aid is acknowledged in my 1963a paper which this work extends. I also gratefully acknowledge the editorial efforts of Joan M. and Frederick R. Schram whose long continued help, gentle prodding, and informative advice have brought me so far with this paper. They reassembled the paper from several diverse pieces in which it
267
had survived, and deleted and updated it to accord with some of the findings in the 17 years since most of the manuscript was written (although surprisingly they did not find a great deal to change). Without their efforts this product of my more active carcino- logical days would never have reached print. Deanne Demeré acted as patient typist
through several revisions.
LITERATURE CITED
Balss, H. 1922. Studien an fossilen Decapoden. Palaeont. Zeitschr. 5: 123-147.
. 1927. Decapoda. Jn W. Kikenthal and T.
Krumbach, Handbuch der Zoologie 3(1):840-
1038. de Gruyter, Berlin.
1957. Decapoda. Systematik. Jn H. G. Bronn, Klassen and Ordnungen des Tierreichs Bd. 5, Abt., Buch 7, Lief. 12:1505—1672. Aca- demische Verlagsgesellschaft, Leipzig.
Barnard, K. H. 1950. Descriptive catalogue of South African Decapod Crustacea. Ann. S. Afr. Mus. 38: 1-837.
Bate, C. S. 1888. Report on the Crustacea Ma- crura collected by the H.M.S. Challenger dur- ing the years 1873-1876. Rept. Scientific Re- sults Voyage H.M.S. Challenger. Zoology 24: 1-942.
Beurlen, K., and M. F. Glaessner. 1930. Syste- matik der Crustacea Decapoda auf Stammes- geschichtlicher Grundlage. Zool. Jahrb. Abt. f. Syst. 60:49-84.
Boas, J. E. V. 1880. Studier over Decapodernes Slaegtskabsforhold. Vidensk. Selsk. Kristi- ania, Skrifter (5)6:25-210.
Borradaile, L. A. 1907. On the classification of the Decapod Crustaceans. Ann. Mag. Nat. Hist. London (7)19:457-486.
Bouvier, E. L. 1917. Crustacés decapodes (ma- croures marcheurs) provenant des campagnes des yachts Hirondelle et Princesses Alice (1885-1915). Res. Camp. Sci. Monaco 50, 104
. 1925. Les Macroures Marcheurs. Jn Re- ports of the results of dredging under the su- pervision of Alexander Agassiz in the Gulf of Mexico by the U.S. Steamer “‘Blake.’’ Mem. Mus. Comp. Zool. Cambridge, Mass. 47:401- 472.
Burkenroad, M. D. 1934. The Penaeidea of Lou- isiana with a discussion of their world rela- tionships. Bull. Amer. Mus. Nat. Hist. 68:61— 143.
. 1936. The Aristaeinae, Solenocerinae and
Pelagic Penaeinae of the Bingham Oceano-
graphic collection. Materials for a revision of
oceanic Penaeidae. Bull. Bingham Oceanogr.
Coll. New Haven 5(2):1-151.
. 1939. Further observations on Penaeidae
of the Northern Gulf of Mexico. Bull. Bing-
ham Oceanogr. Coll. New Haven 6(6): 1-62.
. 1942. The development and relationships
of Glyphocrangon (Crustacea, Decapoda,
Caridea). Amer. Nat. 76:421-425.
1945. A new Sergestid shrimp with re-
marks on its relationships. Trans. Conn. Acad.
Arts Sci. 36:553-593.
. 1947. Reproductive activities of Decapod
Crustacea. Amer. Nat. 81:392-398.
1963a. The evolution of the Eucarida
(Crustacea: Eumalacostraca) in relation to the fossil record. Tulane Studies in Geology 2(1):3-16.
. 1963b. Comments on the petition concern- ing peneid names (Crustacea: Decapoda) (Z.N.(S.) 962). Bull. Zool. Nom. 20: 169-174.
Calman, R. T. 1909. Crustacea. Jn A treatise on zoology. Part VII (R. Lankester, ed.). Adam and Charles Black, London.
Chace, F. A. 1939. On the systematic status of the crustacean genera, Naushonia, Homoris- cus and Coralliocrangon. Ann. Mag. Nat. Hist. 11:524—530.
Glaessner, M. F. 1960. The fossil decapod Crus- tacea of New Zealand and the evolution of the order Decapoda. New Zealand Geo. Surv. Pa- leont. Bull. 31:1—63.
1969. Decapoda. Jn Arthropoda 4. Part R. Vol. 2. Treatise on Invertebrate Palaeon- tology (R. C. Moore, ed.), p. R399-R533. Geol. Soc. Am. Univ. of Kansas Press, Law- rence.
Gurney, R. 1924. Crustacea. Part IX. Decapod Larvae. British Antarctic Terra Nova Expe- dition (Zoology) 8:37—202.
. 1938. Larvae of Decapod Crustacea. Part
V. Nephropsidae and Thalassinidea. Discov-
ery Rept. 17:291-344.
. 1939. A new species of the decapod genus
Discias Rathbun from Bermuda. Ann. Mag.
Nat. Hist. (11)3:388-393.
. 1941. On the larvae of certain Crustacea
Macrura, mainly from Bermuda. J. Linn. Soc.
11:89-181.
. 1942. Larvae of Decapod Crustacea. Ray Society, London.
Holthuis, L. B. 1947. Biological results of the Snel- lius Expedition. XIV. The Decapoda Macrura of the Snellius Expedition. I. The Stenopodi- dae, Nephropsidae, Scyllaridae and Palinuri- dae. Temminckia 7:1-178.
1955. The recent genera of the caridean and stenopodidean shrimps (Class Crustacea, Order Decapoda, Supersection Natantia) with Keys for their determination. Zool. Verhandl. 26:1—157.
Kubo, I. 1949. Studies on Penaeids of Japan and its adjacent waters. J. Tokyo Coll. Fish. 36: i- 467.
Lebour, M. V. 1934. The life-history of Dromia vulgaris. Proc. Zool. Soc. London 1934:241- 249.
1936. Notes on the Plymouth Processa
(Crustacea). Proc. Zool. Soc. London 1936:
609-617.
.1941. Notes on Thalassinid and Processid larvae (Crustacea: Decapoda) from Bermuda. Ann. Mag. Nat. Hist. (11)7:402-420.
Limbaugh, C., H. Pederson, and F. A. Chace.
268
1961. Shrimps that clean fishes. Bull. Mar. aufbewahrten Formen. Zool. Jahrb. (Abt. f. Sci. Gulf and Caribbean 11:237—257. Syst.) 5:437-540.
Milne-Edwards, H. 1837. Histoire naturelle des . 1892a. Die Decapoden-Krebse des Strass- Crustaces comprenant |’anatomie, la physio- burger Museums. III. Die Abtheilungen der logie et la classification de ces animaux, Vol. Reptantia, Boas: Homaridae, Loricata and II. Paris. Thalassinidea. Zool. Jahrb. Syst. 6:1—57.
Moses, M. J. 196la. Spermatogenesis in the cray- . 1892b. Die Decapoden-Krebse des Strass- fish (Procambarus clarki) Part 1. Structural burger Museums. IV. Die Abtheilungen Gal- characteristics of the mature sperm. J. Bio- atheidea und Paguridea. Zool. Jahrb. Syst. phys., Biochem., Cytol. 9:222—228. 6:241-326.
1961b. Spermatogenesis in the crayfish . 1892c. Die Decapoden-Krebse des Strass- (Procambarus clarki) Part Il. Description of burger Museums. V. Die Abtheilungen Hip- stages. J. Biophys., Biochem., Cytol. 10:301- pidea Dromidea und Oxystomata. Zool. Jahrb. 33333). Syst. 6:532-588.
Nichols, M. L. 1909. Comparative studies in Schram, F. R., R. M. Feldman, and M. J. Cope- Crustacean spermatogenesis. J. Morph. 20:461- land. 1978. The late Devonian Palaeopalae- 478. monidae and the earliest decapod crustaceans.
Ortmann, A. 1890. Die Decapoden-Krebse de J. Paleo. 52:1375-1387.
Strassburger Museums mit besonderer Thompson, D. W. 1910. Historium Animalium Beriicksichtigung der von Herrn. Dr. Doder- (transl.). In The Works of Aristotle, (J. A. lein bei Japan und bei den Lui-Kui-Inseln ge- Smith and W. D. Ross, eds.), Vol. 4. Claren- sammelten und z. Z. im Strassburger Museum don Press, Oxford.
Department of Geology, San Diego Natural History Museum, P.O. Box 1390, San Diego, California 92112 USA.
TRANSACTIONS
7 OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 18 pp. 269-278 22 January 1982
Biomere boundaries in the Phanerozoic time scale
Frederick A. Sundberg and Richard H. Miller
Abstract. Abrupt nonevolutionary changes in the fossil record of trilobites during the Cambrian, without associated evidence of lithologic changes or discontinuities, are known as biomere boundaries. We suggest that biomere boundaries are more widespread in the Phanerozoic time scale than previously reported. Accordingly we have expanded the original biomere concept to include nonevolutionary biotic changes, involving one or more phyla, that are the results of major environmental changes of local or worldwide extent. The effects of these changes on benthic taxa are nearly synchronous on the craton and diachronous in shelf and slope environments. The Ordovician-Silurian boundary may pro- vide an example of this type of biomere boundary as indicated by changes in biota. The existence of a biomere boundary rather than a synchronous time boundary at the traditional Ordovician-Silurian systemic boundary, would indicate that there is a significant amount of time equivalency between the Ashgillian and Llandoverian.
INTRODUCTION
A major focus of the earth sciences since the time of William Smith has been the development and continued refinement of the geologic time scale. Numerous difficul- ties have been encountered, but evidence of considerable progress and standardization recently has been published (Hedberg, 1976; Cohee et al., 1978). Major chronostrati- graphic units (system, series, etc.) and corresponding geochronologic units (period, epoch, etc.) of this time scale have been established on a global scope; by definition, these units have isochronous boundaries. The boundaries of chronostratigraphic units are best defined by well-documented changes in the fossil record. Ideally, these changes are recognized by lineage biozones, based on first occurrences of fossil taxa established at a stratotype section for each boundary (Committee on the Silurian-De- vonian Boundary and Stratigraphy, 1972; Murphy, 1977). In practice, most boundaries and especially system boundaries are poorly defined and difficult to correlate on a global scale. We propose herein that a major obstacle to regional and global correlation of some system boundaries (e.g., Cambrian-Ordovician, Ordovician-Silurian, Permian- Triassic, Cretaceous-Paleogene, etc.) is that they are not isochronous as traditionally assumed, but rather represent intervals of time manifested by biomere boundaries and therefore are diachronous. Consequently they do not meet the requirements of syn- chronous time-stratigraphic boundaries. Biozones previously recognized as represent- ing the upper part of one system (e.g., Ordovician) and those representing the lower part of the overlying system (e.g., Silurian) may be partly or completely time equivalent where they are transected by a biomere boundary. We believe the interval of time for the total duration of a biomere boundary is considerably greater than the interval of time necessary for simple faunal migrations—an interval traditionally considered in- significant by stratigraphers (see sections on Biomere Boundaries and Ordovician-Si- lurian Boundary).
The purpose of this paper is to expand the concepts of biomere and biomere boundaries as originally defined by Palmer (1965a) and to apply the expanded concepts to systemic boundaries. We do not intend to prove that the Ordovician-Silurian bound- ary is a biomere boundary; rather we point out an alternative explanation for the
270
existing data and indicate how this interpretation would affect attempts at regional correlation. The concepts presented here are not restricted to the Ordovician-Silurian boundary but also may apply to other time-stratigraphic boundaries in the Phanerozoic.
BIOMERE BOUNDARIES
Biomeres were first defined on the basis of the stratigraphic distribution of Late Cambrian trilobites in the Great Basin (Palmer, 1965a, 19655). They represent “*.. . a regional biostratigraphic unit bounded by abrupt nonevolutionary changes in the dominant elements of a single phylum. These changes are not necessarily related to physical discontinuities in the sedimentary record and they are, or may be, diachro- nous.’ Subsequent work on the recognition of biomeres and biomere boundaries has been sparse, but they have been recognized in collections of Late Cambrian trilobites from Texas and Oklahoma (Longacre, 1970; Stitt, 197la, 1971b). Changes in Late Cambrian conodonts and inarticulate brachiopods closely correspond with the changes in trilobites reported from the Great Basin (Rowell and Brady, 1976). More recent evidence in support of the biomere concept was provided by the changes in trilobites from a very detailed measured section in the Great Basin (Palmer, 1979).
The changes in trilobites between biomere boundaries were classified into four stages (not chronostratigraphic) by Stitt (197la, 19716); Palmer (1979) has recently modified Stitt’s faunal stages. As most recently described by Palmer (1979), stage one of a biomere follows immediately after a major crisis eliminates most of the existing benthic trilobite taxa, and it is characterized by very low diversity and high abundance of generalist species. Stage two represents an initial evolutionary radiation of remaining stocks and contains relatively short ranging taxa. Stage three is represented by a de- crease in diversity and establishment of new major taxonomic groups. In stage four, trilobites again increase in diversity to fill most or all habitats; this climax in diversity is followed by another crisis. Taylor (1977) and Palmer (personal communication) suggested that Cambrian biomeres were produced by the rising of the thermocline and consequent rapid extinction of warm-water, shelf trilobites; new stocks of colder, deep- er-water trilobites subsequently migrated into the depauperate habitats on shelf areas and then underwent adaptive radiations. Of interest is the fact that no biomeres have yet been formally proposed in rocks younger than Cambrian (500 m.y.) in age.
A significant new stratigraphic concept is available if the original concept of bio- mere is expanded as follows: 1) biotic changes at biomere boundaries are due to major environmental changes of local or worldwide extent; 2) biotic changes may affect one or more phyla; 3) in cratonic seas these changes may appear to be essentially syn- chronous (Palmer, 1978), whereas in offshore (shelf or slope) environments the changes may be diachronous; and 4) the diachroneity of a biomere boundary may span millions of years (discussed below). This expanded concept of a biomere may provide a more accurate explanation for many erathemic or systemic boundaries previously considered synchronous, unconformable, or paraconformable.
We believe that the diachroneity of a biomere boundary may span millions of years (point 4 of above). Our belief is based on faunal patterns of the Ordovician- Silurian boundary (see following section on the Ordovician-Silurian boundary) and the nature of the invading stock. The invading stock originates from genetically conser- vative, deeper-water faunas. The genetically conservative nature of the group is sug- gested by 1) the morphological similarity between invading stocks of different biomeres (Palmer, 1965a), suggesting a common basic stock for the invading trilobites which were evolving much slower than the contemporaneous shallow-water taxa; 2) the less dense populations in modern deep-sea environments (Ingle, 1975; Wigle and Emery, 1967) because it is harder to find a mate; 3) the reduction in egg numbers, K-mode reproduction, in modern deep-sea faunas (Allen, 1979; Sanders, 1979; Rex, 1979); and 4) the extreme lengths of time between generations due to the ‘‘late’’ sexual maturity of modern deep-water faunas (Allen, 1979; Sanders, 1979; Rex, 1979).
For a genetically conservative invading stock to migrate from the stable, colder,
271
"SLOPE" "SHELF" "“CRATON"
Section Section Section Xx Nf
5 SEE = | Vio sata
92 | aa ISS Se ea 2 ad a ey
| ity a A | a ET | Liat [zak ca Al
eg ‘ / / é “ANCESTRAL SMEG Ey 7* STOCKS Ficure |. Generalized concept of a biomere boundary. Al through A4 and BI through B3 represent lineage
biozones based on benthic or nekto-benthic organisms. Evolution of *‘group’’ A continues in onshore areas not yet affected by environmental change. Lineage B taxa migrate onshore from deeper—or open—oceanic environments and undergo diversification to fill niches vacated by extinction of lineage A taxa. Taxa used to define the base of each successive biozone are indicated by heavy lines. Use of **A’’ and **B” in the diagram is not related to the use of letters to designate Lower Silurian brachiopod biozones.
higher pressure, darker waters of a deeper environment to shallow, unstable, warmer, lighter, and lower pressure waters of depauperate habitats involves not only movement of the stock but also adaption (evolution) of the organism to different environmental conditions. The slow evolution of this genetically conservative group could easily take millions of years. It should be noted that the duration of the changing environment at a specific locality is short, perhaps less than 10,000 years (Palmer, 1979).
Figure | illustrates our concept of a biomere boundary. The boundary is diachro- nous and becomes progressively younger from the slope to the craton through time as extinctions of taxa followed migrating environmental changes. This diagram indicates that four significant features are associated with the biomere. First, in traditional in- terpretations, biozones Al through A4 would all be considered geologically older than biozones BI through B3, although portions of A3 and A4 are lateral biofacies (and temporally equivalent) to portions of BI, B2, and B3. Second, at any section (x, y, or z) one or more lineage biozones (based upon first occurrence) might be missing, and this might be ascribed incorrectly to the existence of a paraconformity. Third, taxo- nomic diversity is lowest just above the boundary, but then increases as new taxa evolve and occupy previously vacant habitats. Fourth, the time involved for the entire boundary event may encompass several biochrons and thus the boundary represents considerably more time than the acceptable diachroneity of chronostratigraphic bound- aries; note that in any single location the event occurs much more rapidly. Attempts to use traditional methods of correlation for an interval characterized by a biomere event would yield spurious results since sections from geographically distant areas would contain differing biozonal sequences. This evidence might be used to suggest the existence of an unconformity or a paraconformity in areas where biozones appear to be ‘‘missing.’’ Also, a stratotype for time intervals characterized by this type of boundary could be selected in a specific geographic location, but it could not be easily correlated with other regions.
Evidence from the fossil record for the Ordovician-Silurian boundary provides an
DID
example for the concepts presented above; studies for the last 100 years using tradi- tional techniques and assumptions have not produced a satisfactory chronostrati- graphic horizon. Three difficulties in illustrating the above concepts are: 1) paleonto- logical studies are commonly confined to one system and do not treat changes in taxa across boundaries; 2) few studies treat shelf to slope paleoenvironments for refined time intervals; and 3) detailed stratigraphic data (such as for the Upper Cambrian strata in the southern Great Basin) often are inconclusive or unavailable.
ORDOVICIAN-SILURIAN BOUNDARY
Lapworth (1879) defined the Ordovician-Silurian boundary using graptolite succes- sions occurring in a sequence of marine strata exposed in the British Isles. The grap- tolite successions used by Lapworth (1879) and by Ellis and Wood (1914-1918) are known from few sections and are poorly correlated with benthic fossils (Berry, 1976). In the last hundred years considerable efforts to correlate this boundary have resulted in the recognition of what appears to represent a worldwide unconformity in paleoen- vironments of the shelf and craton (Berry and Boucot, 1970, 1972a, 1972b, 1973a; Ziegler et al., 1974; Talent et al., 1975). This unconformity coincides with an erosion surface in some areas, but is recognized solely by the absence of biozones in other areas, thus implying the existence of a paraconformity. Poorly understood benthic taxa associated with the boundary are of low diversity and have been assigned to the Or- dovician Period or Silurian Period by various authors (review by Cocks and Price, 1975).
The Ordovician-Silurian boundary is characterized by the following features in various regions: |) poorly distributed graptolite successions; 2) physical unconformity; 3) missing biozones (paraconformity); and 4) low diversity benthic faunas that have not been precisely correlated and appear to be diachronous. Recognition of a stan- dardized boundary, synchronous or nearly synchronous on a global scale, has not been accomplished. We propose an alternative model that explains the apparent paracon- formities and unusual temporal and spatial distribution of the benthic taxa, and that indicates the Ordovician-Silurian transition may represent a biomere boundary.
Graptolite Successions.—The Ordovician-Silurian boundary was originally de- fined on the basis of graptolite successions in western Europe, and similar successions have been reported from other areas (Berry and Boucot, 1970). The latest Ordovician is recognized by the occurrence of Diplograptus anceps and Climatograptus promi- nenselongatus (Riva, 1974; Williams, 1976). Basal Silurian graptolite biozones are Ak- idograptus acuminatus and, locally, Glyptograptus persculptus or other biozonal in- dicators. Other taxa, including conodonts, ostracodes, brachiopods, corals, trilobites, and cephalopods, have been correlated with the successions. A significant difficulty in correlation is that graptolites are rarely associated with shelly faunas, especially in Upper Ordovician and Lower Silurian rocks (Williams, 1969; Ingham and Wright, 1970; Berry, 1976). A further factor is that benthic shelly faunas were affected more strongly by bottom environmental conditions than were the graptolites, and different shelly faunas may be associated with the same graptolites. We have concluded that graptolites provide more accurate correlation for slope sequences (pelagic argillite-chert belt of Erdtmann, 1976) spanning the Ordovician-Silurian boundary. Recognition and corre- lation of this boundary in shallow-water carbonate or clastic sequences is difficult because graptolites were rarely preserved in these sequences.
Unconformities.—In areas containing shelly faunas, the Ordovician-Silurian boundary most commonly is considered to be unconformable (Berry and Boucot, 1970, 1972a, 1972b, 1973a; Ziegler et al., 1974; Talent et al., 1975). In many cratonic sections of North America the base of the Silurian reportedly rests unconformably on Upper Ordovician rocks (Berry and Boucot, 1970). This regional unconformity has been re- lated to an Early Silurian regression associated with glaciation (Berry and Boucot, 1973b; Sheehan, 1973). In some areas evidence for an unconformity is based upon the reported absence of earliest Silurian (early and middle Llandoverian) fossils (Rexroad
pia fe)
et al.. 1965; Rexroad, 1967:15—16), thus suggesting the existence of a paraconformity. Shallowing and erosion of shelf areas has been reported by Lenz (1976) for the northern Cordillera. However, evidence reported by Johnson and Potter (1976), Miller (1976), Dunham (1977), and Miller and Walch (1977) indicates that deposition was continuous across the boundary interval in the southern Cordillera.
Considerable difficulty in recognition of the boundary has been noted for the Cel- lon section (shelf sequence) in the Carnic Alps and the Welsh borderland (Walliser, 1964. 1971: Schénlaub, 1971; Aldridge, 1972, 1975). Shallow-water sequences (based upon brachiopod communities) are characterized by the absence of early Llandoverian shelly faunas and by the existence of an unconformity separating Ordovician and Si- lurian rocks. However, as we have noted, shelly fauna biozones are poorly correlated with deeper water graptolite faunas and the existence and stratigraphic position of these unconformities is not well established (note especially Schonlaub, 1971:37, fig. 2 for Cellon section).
Diachronous Benthic Faunas.—An example of a diachronous benthic fauna is the ‘‘Hirnantian fauna.’’ This fauna is typically a low diversity assemblage of brachiopods and trilobites with other minor shelly elements and is known from Europe, Asia, and North America (Wright, 1968; Nikitin, 1971, 1976; Sch6nlaub, 1971; Cocks and Price, 1975: Lesperance and Sheehan, 1976). This fauna was originally used by Bancroft (1933) to define a stage of post-Ashgillian age, but Ingham and Wright (1970) placed the Hirnantian Stage in the Ashgillian. Cocks and Price (1975) and Lesperance and Sheehan (1976) indicated that the Hirnantian fauna appeared to be diachronous and therefore could not be equivalent to the Hirnantian Stage.
Published information indicates that the fauna ranges in age from Ashgillian to medial Llandoverian (Nikitin, 1971, 1976; Schénlaub, 1971; Cocks and Price, 1975; Lesperance and Sheehan, 1976). Nikitin reported a Hirnantian fauna in the central USSR associated with the graptolite Glyptograptus persculptus, indicative of the G. persculptus Biozone (=Zone 16) of the earliest Llandoverian. Cocks and Price (975) did not consider Nikitin’s fauna to be Hirnantian, but the faunal list includes Mucro- naspis (Dalmanitina) macronata, Eostropheodonta aff. squamosa, Dalamanella tes- tudinaria, and Hirnantia species, which, at the generic level, represent common Hir- nantian taxa.
Further evidence of the age relationships of the fauna is in the Carnic Alps of Austria and Italy. Schénlaub (1971: fig. 2) illustrated a Hirnantian fauna interbedded and coexisting with the conodont Amorphognathus ordovicica, diagnostic of Late Or- dovician (Ashgillian) age. Cocks and Price (1975) discussed the Hirnantian fauna from the St. Martin’s Cemetary Horizon in Wales, which occurs above strata of Rawtheyan age (Late Ordovician) and below faunas of early Llandoverian age. Lesperance and Sheehan (1976) discussed the occurrence of a Hirnantian fauna in Quebec that lies above lower or middle Ashgillian and below Llandoverian beds and is associated with the graptolite Cliograptus rectangularismedius of Early Silurian age. They also pre- sented evidence (1976:721) from the type locality suggesting that the Hirnantian fauna may be of early and medial Llandoverian age. From the foregoing we conclude that the Hirnantian fauna is a diachronous ‘‘community,’’ as suggested by Cocks and Price (1975), and should not be used to define a time-stratigraphic unit.
A second example of a diachronous benthic or nekto-benthic fauna ts the distribution of conodont biozones. Detailed conodont biozones for latest Ordovician and earliest Silurian time in North America are not well established. Sweet et al. (1971) recognized Late Ordovician faunas (Faunas 10, 11, 12) and Nicoll and Rexroad (1968) and Pollock et al. (1970) recognized Early Silurian biozones (Panderodus simplex, Icriodina irre- gularis, Neospathognathodus celloni Assemblage Biozones). These have been recog- nized in mid-continental cratonic paleoenvironments but are poorly known from off- shore (shelf or slope) paleoenvironments.
The Panderodus simplex Assemblage Biozone was named by Pollock et al. (1970:746) for conodonts occurring in a sequence of rocks below the lowest occurrence of Icriodella discreta or Icriodella new species or the genus Icriocina and above
274
diagnostic Ordovician species. This biozone contains a low diversity assemblage of simple-cone species and, although considered earliest Silurian, also contains Ordovi- cian species (Craig, 1969; Walliser, 1971; Barnes et al., 1973; Liebe and Rexroad, 1977:844). The P. simplex Biozone has not been recognized in rocks deposited in shelf or slope paleoenvironments, although Miller (1975, 1976) and Audell and Miller (1979) reported nondiagnostic simple-cone taxa above Upper Ordovician rocks and below upper Llandoverian rocks in the southern Great Basin (shelf).
From these examples we conclude that the Hirnantian fauna and the P. simplex Biozone are diachronous and geographically transgressive (and partially regressive) pioneer assemblages (definition of assemblage following Kauffman and Scott, 1976) that existed after other Ordovician taxa were eliminated. This pioneer assemblage is much like stage 4 (not time stratigraphic) of a biomere (Stitt, 197la) or stage | of Palmer (1979), where the extinction of specialized forms occurred, but the generalists were not affected.
Brachiopod Distribution. —Sheehan (1973, 1975) discussed the abrupt changes in brachiopods that occurred across the Ordovician-Silurian boundary. He described Late Ordovician brachiopod faunas as containing many stenotopic species, especially those existing in shallow-water (cratonic) paleoenvironments. These species became extinct because of an ‘‘ecologic crisis’’ at the end of Ordovician time, although the precise dating is difficult to determine. New taxa in the Early Silurian were derived from taxa existing in the open ocean (off the continental platform) that migrated into the empty niches from offshore paleoenvironments. He also noted that the diversity of Early Silurian brachiopods was low and did not stabilize until late Llandoverian time. These abrupt faunal changes were attributed to the onset of glaciation and consequent regres- sion that eliminated many Late Ordovician niches. However, the distribution and evo- lution of brachiopod taxa also provide significant support for our biomere model.
DISCUSSION AND CONCLUSIONS
The boundaries of time-stratigraphic (chronostratigraphic) units are based upon evidence from the fossil record. Implicit in their definition and recognition is the as- sumption that, despite homotaxis as described by Huxley in the 1800s, the boundaries are synchronous on a global scale. Since the first definition of the Ordovician-Silurian boundary by Lapworth (1879) to resolve previous conflict over the Cambrian-Silurian boundary, attempts to recognize and correlate this boundary on a worldwide scale have been difficult. This difficulty is reflected by the contradictory information that includes peculiar or unusual associations of taxa, and the ever-present ‘‘paraconfor- mity’’ reported in the literature. We suggest that the paleontological evidence can be interpreted differently. The changes in biota were due to environmental changes that produced an episode of extinction with significant diachroneity but which are not nec- essarily related to changes in lithology. Therefore, the Ordovician-Silurian boundary may be interpreted as a biomere boundary.
In Figure 2 we show the traditional concept of the Ordovician-Silurian boundary (Fig. 2a) and two models (Figs. 2b, 2c) that illustrate the Ordovician-Silurian transition as a biomere boundary. Our interpretation of the traditional model (Fig. 2a) is based upon reported distribution of unconformities and biota. Using either of the two biomere boundary models (Figs. 2b and 2c), it is evident that in offshore areas (slope and shelf) currently recognized shelly faunas of Late Ordovician (Ashgillian) age would be absent
=>
Ficure 2. Three interpretations of the Ordovician-Silurian boundary. a) Traditional interpretation illus- trating continuous deposition in deeper water (slope) and unconformity in shallow water (shelf and craton). b) Biomere boundary, illustrating diachroneity and relationships of established biozones to the boundary. c) Biomere boundary, illustrating greater diachroneity. The Hirnantian fauna (dotted line) and Panderodus simplex Biozone (dashed line) are low diversity time-transgressive associations and are found with Ordo- vician and Silurian taxa. Actual position of the biomere boundary is approximate.
outer inner a. SLOPE SHELF CRATON c6|25 P. amorphognathoides : : z \Cli2l S_celloni ira w |BS z re) }° = hay 5 /. irregularis 2 | ae 4 — Panderodus , simplex , ii 5 ar Al lie LS Gus A 15 LL AN/, Me Zz 4 e Ve 2 - = = : pieraaiianie 5 a.
< 5 irnantian png VL 2 2 2 = = 8 3 = graptolites shelly fossils FAUNA /O < 5 S b.
S. celloni
°
= a . z
= Panderodus simplex a ty /. frregu/aris Biozone~ a > e °@ e e e e e e e e e ° S e © i ¢ e? — 4
pas FAUNA /2 Hirnantian fauna
FAUNA //
ASHGILLIAN
FAUNA 1/0
CARADOCIA
P. amorphognathoides
Panderodus simp/ex
S. celloni : y Biozone e e e
LLANDO.
/. irregu/aris
FAUNA 1/2
e a s Ge FAUNA // Hirnantian fauna
FAUNA 1/0
CARADOCIAN
CARADOCIAN
276
or only partially represented, but shelly faunas of Early Silurian (early and middle Llandoverian) age would be found. Onshore areas (craton) would contain faunas of Ashgillian age, but would lack currently recognized shelly faunas of early Llandoverian age. Not all of the data presented agree with the proposed models, but differences are generally minor and may be due to oversimplification in the diagrams. The influence of paleobiogeography was not taken into account; thus it may be necessary to construct other diagrams for different biotic provinces.
The existence of a biomere boundary would necessitate a redefinition of the sys- temic boundary. The most reasonable redefinition would establish the boundary at the base of the Ashgillian or at the base of the late Llandoverian and thereby employ well- established sequences of shelly faunas as well as graptolites. Another possibility would be to retain the traditional definition of the Ordovician-Silurian boundary based on typically *‘Ordovician faunas”’ and **Silurian faunas,”’ and recognize that the boundary is diachronous, and therefore not a chronostratigraphic boundary. The recognition of the boundary would be based on different defining and/or characterizing taxa in dif- ferent depositional settings (slope, outer and inner shelf, and craton).
Biomeres and biomere boundaries have been documented in the Cambrian and for the Cambrian-Ordovician boundary (Stitt, 19715; J. F. Miller, unpublished data). In our study a biomere boundary is suggested for the Ordovician-Silurian boundary. Other boundaries in the Phanerozoic time scale may prove to be biomeres. Other possible biomere boundaries revealed by a brief survey of the literature include the Permian- Triassic, Triassic-Jurassic, Jurassic-Cretaceous, and Cretaceous-Paleogene.
Recognition of a major biomere boundary would require detailed measurements of strata and descriptions of taxa across the proposed boundary from a number of sections in deep-water (slope), shallow-water (shelf), and craton paleoenvironments. These sections should be taken as close as possible along a single paleolatitude; aux- iliary sections should be located normal to the first line of sections and ideally should cover a significant band of latitude. Although suffering from a lack of many detailed studies, the widespread Paleozoic rocks in the western United States (Cordilleran region) represent slope, shelf, and craton paleoenvironments (Stewart et al., 1977); and these could provide the data necessary to document the existence of biomere bound- aries.
Although biomeres currently have important stratigraphic implications only for Cambrian rocks, we suggest that the fossil record for younger strata supports expansion of the concept to include larger events on a global scale. These biomere boundaries represent major stratigraphic markers and have not been recognized through most of the Phanerozoic rock record, and they provide a new explanation for the lack of correlations of many traditionally defined chronostratigraphic and geochronologic boundaries.
ACKNOWLEDGMENTS
A number of people have reviewed various drafts of this paper and we appreciate their comments. It should be noted that most have not agreed with our ideas as pre- sented. We extend thanks to Gretchen Bender, William Berry, Robin Cocks, Ray Ethington, Alfred Fischer, Jess Johnson, Mike Murphy, Norman Newell, Fred North, Allison Palmer, Gary Peterson, Laurie Raucoba, James Stitt, and Keith Young. We especially thank John Cooper, Fred Schram, and Peter Sheehan.
LITERATURE CITED
Aldridge, R. J. 1972. Llandovery conodonts from Allen, J. A. 1979. The adaptations and radiation the Welsh Borderland. Bulletin of the British of deep sea bivalves. Sarsia 64: 19-27. Museum of Natural History (Geology) 22:125- Audell, H. S., and R. H. Miller. 1979. Upper Or- 223i dovician and lower Silurian rocks from the
1975. The stratigraphic distribution of Panamint Range, Inyo County, California. conodonts in the British Silurian. Journal Geo- Geological Society of America, Abstracts with
logical Society of London 131:607-618. Program I1 (3):67.
Bancroft, B. B. 1933. Correlation tables of the stages Costonian-Onnian in England and Wales. Privately published, Blakeney, Glas- gow.
Barnes, C. R., C. B. Rexroad, and J. F. Miller. 1973. Lower Paleozoic conodont provincial- ism. Pages 156-190 in F. H. T. Rhodes, editor. Conodont Paleozoology. Geological Society of America, Special Paper 141.
Berry, W. B. N. 1976. Aspects of correlation of North American shelly and graptolitic faunas. Pages 153-170 in M. G. Bassett, editor. The Ordovician System. Proceedings of a Palaeon- tological Association Symposium, Birming- ham, September 1974. University of Wales Press and National Museum of Wales, Cardiff.
,and A. J. Boucot. 1970. Correlation of the
North American Silurian rocks. Geological
Society of America, Special Paper 102.
, and 1972a. Correlation of the South American Silurian rocks. Geological Society of America, Special Paper 133.
———, and 1972b. Correlation of the Southeast Asian and near Eastern Silurian rocks. Geological Society of America, Special Paper 137.
, and . 1973a. Correlation of the Af-
rican Silurian rocks. Geological Society of
America, Special Paper 147.
, and 1973b. Glacio-Eustatic con- trol of Late Ordovician-Early Silurian Plat- form sedimentation and faunal changes. Geo- logical Society of America Bulletin 84:275— 284.
Cocks, lb) Ro Mand) D> Price) 19752 The bio- stratigraphy of the Upper Ordovician and Lower Silurian of southwest Dyfed, with com- ments on the Hirnantia Fauna. Palaeontology 18:703-724.
Cohee, G. V., M. F. Glaessner, and H. D. Hed- berg, editors. 1978. The Geologic Time Scale. American Association of Petroleum Geolo- gists, Studies in Geology 6.
Committee on the Silurian-Devonian Boundary and Stratigraphy. 1972. Report to the Presi- dent of the Commission on Stratigraphy— Recommendations. Geology Newsletter 4: 268-288.
Craig, W. W. 1969. Lithic and conodent succes- sion of Silurian strata, Batesville District, Ar- kansas. Geological Society of America Bulle- tin 80:1621-1628.
Dunham, J. B. 1977. Depositional environments and paleogeography of the Upper Ordovician, Lower Silurian carbonate platform of central Nevada. Pages 157-164 in J. H. Stewart, C. H. Stevens, and A. E. Fritsche, editors. Pa- leozoic Paleogeography of the Western United States. Pacific Coast Paleogeography Sympo- sium 1, Pacific Section, Society of Economic Paleontologists and Mineralogists, Los Ange- les, California.
Ellis, G. L., and E. M. R. Wood. 1914-1918. A monograph of British graptolites. Paleonto- logical Society Monograph.
Erdtmann, B. D. 1976. Ecostratigraphy of Ordo- vician graptoloids. Pages 621-644 in M. G. Bassett, editor. The Ordovician System. Pro-
ceedings of a Palaeontological Association Symposium, Birmingham, September 1974. University of Wales Press and National Mu- seum of Wales, Cardiff.
Hedberg, H. D., editor. 1976. International Strati- graphic Guide. John Wiley & Sons, New York.
Ingham, J. K., and A. D. Wright. 1970. A revised classification of the Ashgill Series. Lethaia 3:233-242.
Ingle, J. C., Jr. 1975. Paleoecologic indicators and trace fossils. Pages 8-1-8-11 in W. R. Dickin- son, editor. Current Concepts of Depositional Systems with Applications for Petroleum Ge- ology. San Joaquin Geol. Soc. Short Course.
Johnson, J. G., and E. C. Potter. 1976. Silurian (Llandovery) downdropping of the western margin of North America. Geology 3:331-334.
Kauffman, E. G., and R. W. Scott. 1976. Basic concepts of community ecology and _ paleo- ecology. Pages 1-28 in R. W. Scott and R. R. West, editors. Structure and Classification of Paleocommunities. Dowden, Hutchinson, & Ross, Inc., Stroudsburg, Pennsylvania.
Lapworth, C. 1879. On the tripartite classification of the Lower Paleozoic rocks. Geological Magazine, new series, Ded. 11 6:1-15.
Lenz, A. C. 1976. Late Ordovician-Early Silurian glaciation and the Ordovician-Silurian bound- ary in the northern Canadian Cordillera. Ge- ology 4:313-317.
Lesperance, P. J., and P. M. Sheehan. 1976. Bra- chiopods from the Hirnantian Stage (Ordovi- cian-Silurian) at Perce, Quebec. Palaeontology 19:719-731.
Liebe, R. M., and C. B. Rexroad. 1977. Con- odonts from Alexandrian and Early Niagaran rocks in the Joliet, Illinois area. Journal of Pa- leontology 51:844-857.
Longacre, S. A. 1970. Trilobites of the Upper Cambrian ptychaspid biomere Wilberns For- mation, central Texas. Journal of Paleontology Memoir 4.
Miller, R. H. 1975. Late Ordovician-Early Silu- rian conodont biostratigraphy, Inyo Moun- tains, California. Geological Society of Amer- ica Bulletin 86: 159-162.
1976. Revision of Upper Ordovician, Si-
lurian, and Lower Devonian stratigraphy,
southwestern Great Basin. Geological Society
of America Bulletin 87:961—968.
, and C. A. Walch. 1977. Depositional en- vironments of Upper Ordovician through Lower Devonian rocks in the southern Great Basin. Pages 165-180 in J. H. Stewart, C. H. Stevens, A. E. Fritsche, editors. Paleozoic Paleogeography of the Western United States. Pacific Coast Paleogeography Symposium 1. Pacific Section, Society of Economic Paleon- tologists and Mineralogists, Los Angeles.
Murphy, M. A. 1977. On time-stratigraphic units. Journal of Paleontology 51:213-219.
Nicoll, R. S., and C. B. Rexroad. 1968. Stratig- raphy and conodont paleontology of the Sal- amonie Dolomite and Lee Creek Member of the Brassfield Limestone (Silurian) in south- eastern Indiana and adjacent Kentucky. In- diana Geologic Survey Bulletin 40.
278
Nikitin, I. F. 1971. The Ordovician System in Kazakhstan. Memoir of the Bureau Rech. Ge- ology and Mineralogy 73:337-343.
1976. Ordovician-Silurian deposits in the Chu-Ili Mountains (Kazakhstan) and the prob- lem of the Ordovician-Silurian Boundary. Pages 293-300 in M. G. Bassett, editor. The Ordovician System. Proceedings of a Palaeon- tological Association Symposium, Birming- ham, September 1974. University of Wales Press and National Museum of Wales, Cardiff.
Palmer, A. R. 1965a. Biomere—a new kind of bio- stratigraphic unit. Journal of Paleontology 39: 149-152.
. 1965b. Trilobites of the Late Cabrian pter-
ocephaliid biomere in the Great Basin, United
States. United States Geological Survey
Professional Paper 493.
1978. The anatomy of a biomere bound-
ary. Geologic Society of America Abstracts
and Programs 10:467.
1979. Biomere boundaries re-examined. Alcheringa 3:33-42.
Pollock, C. A., C. B. Rexroad, and R. S. Nicoll. 1970. Lower Silurian conodonts from north- ern Michigan and Ontario. Journal of Paleon- tology 44:743-764.
Rex, M. A. 1979. r- and K-selection in a deep-sea gastropod. Sarsia 64:29-32.
Rexroad, C. B. 1967. Stratigraphy and conodont paleontology of the Brassfield (Silurian) in the Cincinnati Arch area. Indiana Geologic Sur- vey Bulletin 36.
, E. R. Branson, M. O. Smith, C. H. Sum- merson, and A. J. Boucot. 1965. The Silurian formations of east-central Kentucky and ad- jacent Ohio. Kentucky Geologic Survey Bul- letin 2, series X.
Riva, J. 1974. A revision of some Ordovician graptolites of eastern North America. Pa- laeontology 17:1-40.
Rowell, A. J., and M. J. Brady. 1976. Brachio- pods and biomeres. Brigham Young Univer- sity Geologic Studies 23:165—180.
Sanders, H. L. 1979. Evolutionary ecology and life-history patterns in the deep sea. Sarsia 64: 1-7.
Schonlaub, H. P. 1971. Zur Problematik der Cono- donter—Chronologie und der Wende Ordoviz/ Silur mit besonderer Berucksichtigung der Verhaltnisse in Llandovery. Geologica et Pa- laeontologica 5:35-57.
Sheehan, P. M. 1973. The relation of Late Ordo- vician glaciation to the Ordovician-Silurian changeover in North American brachiopod faunas. Lethaia 6:147-154.
. 1975. Brachiopod synecology in a time of crisis (Late Ordovician-Early Silurian). Paleo- biology 1:205-212.
Stewart, J. H., C. H. Stevens, and A. E. Fritsche, editors. 1977. Paleozoic Paleogeography of the Western United States. Pacific Section,
Society of Economic Paleontologists and Min- eralogists, Symposium 1.
Stitt, J. H. 1971la. Repeating evolutionary pattern in Late Cambrian trilobite biomeres. Journal of Paleontology 45:178-181.
1971b. Late Cambrian and earliest Or- dovician trilobites. Timbered Hills and Low- er Arbuckle Groups, western Arbuckle Moun- tains, Murray County, Oklahoma. Oklahoma Geological Survey Bulletin 110.
Sweet W. C., R. L. Ethington, and C. R. Barnes. 1971. North American Middle and Upper Or- dovician conodont faunas. Pages 163-193 in W. C. Sweet and S. M. Bergstrém, editors. Symposium on Conodont Biostratigraphy. Geological Society of America Memoir 127.
Talent, J. A., W. B. N. Berry, and A. J. Boucot. 1975. Correlation of the Silurian rocks of Aus- tralia, New Zealand, and New Guinea. Geo- logical Society of America, Special Paper 150.
Taylor, M. E. 1977. Late Cambrian of western North America: Trilobite biofacies, environ- mental significance, and biostratigraphic im- plications. Pages 397-425 in E. G. Kauffman and J. E. Hazel, editors. Concepts and Meth- ods of Biostratigraphy. Dowden, Hutchinson & Ross, Inc., Stroudsburg, Pennsylvania.
Walliser, O. H. 1964. Conodonten des Silurs. Ab- handlungen des Hessisches Landesamtes fur Bodenforschung 41.
. 1971. Conodont biostratigraphy of the Si- lurian of Europe. Pages 195-206 in W. C. Sweet and S. M. Bergstrom, editors. Sympo- sium on Conodont Biostratigraphy. Geological Society of America Memoir 127.
Wigle, R. L., and K. O. Emery. 1967. Benthic animals, particularly Hyalinoecia (Annelida) and Ophiomusiam (Echinodermata), in sea- bottom photographs from the continental slope. Johns Hopkins Oceanographic Studies 3:235-249.
Williams, A. 1969. Ordovician of British Isles. Pages 236-264 in M. Kay, editor. North At- lantic—Geology and Continental Drift. Amer- ican Association of Petroleum Geologists Memoir 12.
1976. Plate tectonics and biofacies evo- lution as factors in Ordovician correlation. Pages 29-66 in M. G. Bassett, editor. The Ordovician System. Proceedings of a Palaeon- tological Association Symposium, Birming- ham, September 1974. University of Wales Press and National Museum of Wales, Cardiff.
Wright, A. D. 1968. A westward extension of the Upper Ashgillian Hirnantia fauna. Lethaia 1:352-367.
Ziegler, A. M., R. B. Richards, and W. S. Mc- Kerrow. 1974. Correlation of the Silurian Rocks of the British Isles. W. B. N. Berry and A. J. Boucot, editors. Geological Society of America, Special Paper 154.
Sundberg: Department of Geology, Museum of Northern Arizona, Rt. 4, Box 720, Flagstaff, Arizona 86001 USA; and Miller: Allison Center, Department of Geological Sciences, San Diego State University, San Diego, California 92182 USA.
Bs 4a <
“\
TRANSACTIONS OF THE SAN DIEGO SOCIETY OF NATURAL HISTORY
Volume 19 Number 19 pp. 279-296 6 August 1982
The origin of Darwin’s finches (Fringillidae, Passeriformes)
David W. Steadman
Abstract. Despite numerous studies of the group, the ancestry of Darwin’s finches, consisting of the Cocos Finch (Pinaroloxias inornata) and the Galapagos finches (13 species of Geospiza, sensu lato), has never been adequately resolved. Striking similarities in osteology and plumage indicate that the Blue-black Grassquit, Volatinia jacarina, an emberizine finch of Central and South America, may be the direct ancestor of Darwin’s finches. The Cocos Finch and the Galapagos finches evolved from independent colonizations of Volatinia from the Neotropical mainland, and thus their similarities are largely due to retention of ancestral characters present in Volatinia. Evidence for a supposed close relationship between Darwin’s finches and Tiaris or Melanospiza of the West Indies either is unsub- stantiated or involves characters that are found also in Volatinia. Geological data reveal very young ages for both the Galapagos (3-5 million years for the oldest islands) and Cocos Island (1 million years), thus limiting the possible age of terrestrial life on these islands. The ancestral relationship of living Volatinia to Darwin’s finches is compatible with the relatively recent origin of the rest of the terrestrial avifauna of the Galapagos, whose nearest relatives also are in western South America and not in the West Indies. The strong resemblance between Volatinia and Darwin’s finches is best ex- pressed by including Volatinia Reichenbach 1850, in the genus Geospiza Gould 1837. Because of the intergradation among the various species of Galapagos finches and their similarity to the Cocos Finch and Volatinia, the genera Pinaroloxias Sharpe 1885, Platyspiza Ridgway 1897, Camarhynchus Gould 1837, Cactospiza Ridgway 1897, and Certhidea Gould 1837, are also treated as synonyms of Geospiza.
Resumen. A pesar de las investigaciones numerosas de group, la herencia de los pinzones Darwin, que incluyen el pinzon de Cocos (Pinaroloxias inornata) y los pinzones de Galapagos (13 especies de Geospiza, sensu lato), nunca ha sido adecuadamente resuelta. Semejanzas impresionantes en osteologia y plumaje indican que el marinerito, Volatinia jacarina, un pinzon “‘emberizine’’ de América Central y América del Sur, tal vez es el ascendiente directo de los pinzones Darwin. El pinzon de Cocos y los pinzones de Galapagos evolucionaron de colonizaciones independientes de Volatinia desde el continente neotropical y, por eso, las semejanzas de ellos se deben mayormente a causa de la retencion de caracteristicas hereditarias presentes en Volatinia. La evidencia para una supuesta relaci6n cercana entre los pinzones Darwin y Tiaris 0 Melanospiza de las Antillas Occidentales, uno de dos, es impalpable o envuelve caracteres que se encuentran también en Volatinia. Datos geologicos indican edades jovenes, tanto para Galapagos (3-5 millones de anos para las islas mas antiguas), como Isla Cocos (1 millon de anos), limitando, de este modo, la posible edad de vida terrestre en estas islas. La relacion hereditaria de la viviente Volatinia con los pinzones Darwin es compatible con el origen relativamente reciente del resto de la avifauna terrestre de los Galapagos, cuyos parientes mas cercanos se encuentran en la parte occidental de Sur América y no en las Antillas Occidentales. La fuerte semejanza entre Volatinia y los pinzones Darwin se expresa mejor incluyendo a Volatinia Reichenbach 1850, en el género Geospiza Gould 1837. A causa de la intergraduacion entre las varias especies de los pinzones de Galapagos y su semejanza con el pinzon de Cocos y Volatinia, los géneros Pinaroloxias Sharpe 1885, Platyspiza Ridgway 1897, Camarhynchus Gould 1837, Cactospiza Ridgway 1897, y Cer- thidea Gould 1837, también son mirados como sinonimos de Geospiza.
INTRODUCTION
Darwin’s finches are small, drab birds that have been studied by many system- atists, evolutionists, and ecologists since the collections and observations of Charles Darwin in 1835. Thirteen species of Darwin’s finches live in the Galapagos Islands (Ecuador), while a single species, Pinaroloxias inornata, lives on Cocos Island (Costa Rica). The various forms of Darwin’s finches in the Galapagos (Geospiza, sensu lato) exhibit a complete gradation between the morphological extremes in overall size and
280
plumage, and their reproductive behavior and ecology are even more uniform. Their remarkable range of bill sizes and shapes provides the main basis for analysis of their evolution and systematics.
A logical first step in understanding the evolutionary radiation of Darwin’s finches is to seek the identity of the ancestral species that first colonized the Galapagos or Cocos Island and subsequently gave rise to the 14 species generally recognized today, following Lack (1947). Progress in the search for this ancestor has been hampered by the fact that the four largest and most comprehensive publications on Darwin’s finches (Swarth, 1931; Lack, 1945, 1947; and Bowman, 1961) have stressed the differences between Darwin’s finches and mainland finches, while largely ignoring or not inter- preting the similarities. This reluctance to attempt to relate Darwin’s finches to main- land birds is perhaps due in part to the influence of Swarth (1929, 1931), who elevated Darwin’s finches to familial rank (Geospizidae). Although Swarth (1929) could not see consistent similarities between Darwin’s finches and any other family, his diagnosis of the ‘‘Family Geospizidae’’ contains no characters that are not also found in certain emberizine finches (Passeriformes: Fringillidae: Emberizinae). Swarth’s ‘‘Geospizi- dae’’ generally has not been recognized by later authors, but is often maintained as a distinct subfamily (Geospizinae) within the Fringillidae (Emberizidae of some workers). This treatment, however, is not phylogenetically consistent with the ancestry of the group as proposed by several of the same authors (Bowman, 1961, 1963; Lack, 1947, 1961: and Harris, 1974), who leave open the possibility of an ancestor for Darwin’s finches in the Parulidae (New World warblers; Mniotiltinae herein), and despair of the futility of determining the real ancestor. For example, Bowman (1961:135) remarked, ‘‘Whether or not the ancestral geospizine was a thin-billed form ... or was more typically finchlike . . . or like any other ‘type’ represented in the subfamily, may never be known. The structural transition in the jaw musculature from one ‘extreme’ to another may be so clearly traced that conjecture about the precise nature of the an- cestral geospizine is really quite meaningless . . . .”’ This statement contradicts others in the monograph where in several places (pp. 178-179) a relationship is suggested, at an unspecified level, between Darwin’s finches and certain genera of Emberizinae, especially Tiaris and Melanospiza. Thus the problem of determining the ancestry of Darwin’s finches is twofold. Firstly, one must determine their correct subfamilial po- sition within the 9-primaried oscines (because of the similar nature of the myology [Raikow, 1978] and osteology of all 9-primaried oscines of the New World except vireos, I regard them all as constituting but a single family, the Fringillidae). Secondly, only after secure allocation to subfamily, one may search for closely related genera and species.
Mainly through detailed myological studies, Raikow (1977) showed that the Hawai- ian finches (Drepanidini) evolved from a single primitive species of the Carduelinae, although he did not specifically state the ancestral genus or species itself. There is no a priori reason why the ancestry of Darwin’s finches cannot also be determined with at least as much resolution, particularly because (1) the range of variation in bill shapes in Darwin’s finches is much smaller than in the Drepanidini (compare pls. 9-12 of Bowman, 1961, with p. 101 of Raikow, 1977); (2) Darwin’s finches consist of only | to 6 poorly differentiated genera, depending on the classification used, while the Hawaiian finches constitute 10 distinct genera, following Raikow (1977); (3) based purely on geographical considerations, we must look no farther than the New World for the ancestors of Darwin’s finches, while the ancestor of the Drepanidini could have come from either the New World or the Old World; and (4) the Galapagos probably have not been available for colonization by land birds for as long a period as the Hawaiian Islands. The oldest islands in the Galapagos appear to be no more than 3-5 million years old (Cox, in press). The oldest ages for Hawaiian Islands inhabited by a diverse assemblage of drepanidines are about 5 million years for Kauai (McDougall, 1979); islands west of Kauai are even older.
My thesis is that Darwin’s finches not only are clearly emberizines, but in fact are so closely related to the living mainland species Volatinia jacarina (Blue-black Grass-
281
quit) that V. jacarina singly gave rise to the entire array of Darwin’s finches, both in the Galapagos and on Cocos Island. After a historical review of other proposed rela- tionships of Darwin’s finches, I will present anatomical data to support my hypothesis, followed by a discussion of nonanatomical evidence. Finally, the evolutionary scheme proposed herein will be analyzed zoogeographically in the chronological framework dictated by recent geological discoveries.
History OF THE PROPOSED RELATIONSHIPS OF DARWIN’S FINCHES
Gould (1843) originally described the Cocos Finch, Pinaroloxias, as Cactornis inornatus, thus correctly placing it with the Galapagos finches. Since Gould’s descrip- tion, the close affinity of Pinaroloxias to at least certain of the Galapagos finches has seldom been questioned. Gray (1859) referred Pinaroloxias to the genus Loxops, thus implying that it is a member of the Drepanidini of Hawaii, while Salvin (1876) stated that the systematic position of Pinaroloxias is uncertain, although probably it is related neither to the Drepanidini nor to the Galapagos finches. Ridgway (1897) regarded Pi- naroloxias to be related both to the Galapagos finches and to Coereba. All other authors either have remained neutral on this matter or have stated that Pinaroloxias is related to the Galapagos finches.
Volatinia has been mentioned twice in previous published accounts of Darwin’s finches, but has never before been suggested as very closely related. Bowman (1961) noted a similarity in the pneumatization pattern of the skull in Darwin’s finches, Vo- latinia, and several other emberizines. Harris (1972) mentioned the similar plumages in Volatinia and Darwin’s finches, but then curiously proposed a possible relationship (also based largely on plumage) between Darwin’s finches and Coereba flaveola. As stated even by Harris (1972), C. flaveola resembles Darwin’s finches less in plumage than does Volatinia; both males and females are black in the melanistic phase of C. flaveola, while only males are black in Darwin’s finches and Volatinia. Harris ignored evidence for the emberizine nature of Darwin’s finches presented in Tordoff (1954a) in stating (1972:168), ‘‘To suggest a link between Coereba and the Geospizinae . . may seem a little rash but it is at least as feasible as assuming an affinity with the Fringillidae or Emberizidae.’’ Harris’s hypothesis is further discredited on osteological evidence presented herein. ,
Various other non-Galdpagos birds have been suggested to be related to Darwin’s finches. Salvin (1876) proposed that Camarhynchus and Geospiza do not have a com- mon ancestor, but instead that Camarhynchus is related to Spermophila (=Sporophila) or Neorhynchus nasesus (=Sporophila peruviana), while Geospiza is related to Gui- raca (=Passerina). Rothschild and Hartert (1899) also subscribed to the closeness of Geospiza and Guiraca. Ridgway (1897) rejected Salvin’s thesis of a Camarhynchus- Neorhynchus relationship, and suggested that Camarhynchus may be related to Pyr- rhulagra (=Loxigilla). Ridgway (1897) also proposed possible close relationships be- tween Geospiza and Cyanoloxia (=Passerina) and Oryzoborus (=Sporophila). Sushkin (1925) vaguely mentioned unspecified osteological similarities between Geospiza and various finches, including Guiraca, Cyanocompsa, and Oryzoborus. All of the hy- pothesized relationships in Salvin (1876), Ridgway (1897), Rothschild and Hartert (1899), and Sushkin (1925) are negated by the dissimilarities of Darwin’s finches to Coereba, Passerina (sensu lato), Sporophila (sensu lato), and Loxigilla (see OSTEO- LOGICAL COMPARISONS).
The often-suggested close affinity of Tiaris to Darwin’s finches is largely unsup- ported by real evidence. Most references discussed below deal with hypothesized relationships of Tiaris to the Galapagos finches and do not specifically mention Pina- roloxias. It may be inferred, however, that most or all of these authors regarded Pi- naroloxias and the Galapagos finches as a monophyletic assemblage. Sushkin (1925:261) appears to be the first person to suggest such a relationship, stating with no supportive evidence, ‘‘Jiaris is most intimately related to the famous Galapagoes [sic] finches, Geospiza .. . ..’ The statement of Lowe (1936:317) is almost as uninformative.
282
‘Finally, I might add that I found melanism a very striking feature among the small Finches of the genus Euetheia [=Tiaris], which I found extremely common on an extremely arid, cactus-grown, and isolated island named Blanquilla, a hundred miles from the coast of Venezuela. The physical conditions of Blanquilla must be remarkably similar to those obtaining in the Galapagos. Some of the Finches I shot there are so similar in appearance to certain species of Darwin’s Finches that it would take an expert to distinguish them.’’ Thus black plumage, a condition found in many 9-pri- maried oscines, is Lowe’s only character. Yet Lack (1945:7) cited the ‘“‘anatomical’”’ studies of Sushkin (1925) and Lowe (1936) as indicating a relationship between Tiaris and Darwin’s finches. Bond (1948, 1978) agreed with Lack but suggested that Melano- spiza is also closely related.
Beecher (1953) studied the internal and external anatomy of a wide variety of oscines and concluded (p. 308), ‘‘In the [horny] palate and externally Melanospiza richardsonii [sic] . . . is similar to Geospiza, and both may have been derived from a widespread Caribbean form like Tiaris.’’ Beecher had no spirit specimen of Melan- ospiza. Beecher’s study lacks detailed word descriptions for the states of various char- acters in Galapagos finches, Volatinia, Tiaris, or Melanospiza, among which only one species of Galapagos finch (G. fortis) is illustrated. As pointed out by Tordoff (1954), there are no unique characters in Beecher’s diagnosis (p. 308) of the “‘Geospizidae”’ that distinguish Galapagos finches from the Emberizinae. Tordoff (1954a:27) noted the presence of unfused or incompletely fused palatomaxillaries in a wide variety of em- berizine genera, including the Galapagos finches and Tiaris, but not in Volatinia. In Tordoff’s Appendix (pp. 35-39), however, the palatomaxillary in Volatinia is assigned to the same character state as that in all Darwin’s finches and in Tiaris olivacea. | agree that Volatinia may have incompletely fused palatomaxillaries, which in fact resemble those of Darwin’s finches more than do those of any species of Tiaris.
Bowman (1961:178, 179) noticed the similarity in pattern and placement of the posterior ‘‘windows’’ of incompletely ‘‘ossified’’ skulls in Darwin’s finches, Volatinia, Tiaris olivacea, T. bicolor, Melanospiza, and Loxigilla violacea, as well as in the probable non-emberizines Caryothraustes poliogaster, Chlorophanes spiza, and Cy- anerpes cyanea. Bowman cautiously used this character (pp. 179, 199-201) as evidence for a possible close relationship among Darwin’s finches, Tiaris, and Melanospiza, while apparently ignoring the presence of the same condition in the other taxa. Because the pattern of cranial ossification (termed ‘‘pneumatization’’ herein) in Darwin’s finch- es is not shared uniquely among emberizines with Tiaris and Melanospiza, it alone cannot be used to ally these three groups without also including Loxigilla and Volatin- id.
Understandably, neither Bock (1963) nor Muller (1973) gave any evidence for their suggestions of a close relationship between Tiaris and Darwin’s finches. Following a study in Tiaris canora and T. olivacea of ‘“‘handedness”’ and use of the foot in holding, Baptista (1976:221) stated, ‘‘The genus Tiaris is regarded as closely related to the geospizines by some authors (see Sushkin, 1925; Paynter, 1970). A study of court- ship and aggressive behaviour in Olive Finches [T. olivacea] revealed some striking similarities with displays of geospizines (Baptista, in preparation). Although holding is not unique to Tiaris spp. among continental emberizines, taken with other characters (anatomy, plumage, behaviour) it supports the affinity between grassquits and Darwin's finches.’’ Several comments are warranted regarding Baptista’s statement: (1) Sushkin (1925), as shown above, did not substantiate his claims; (2) Paynter and Storer (1970) {=Paynter, 1970] did not specifically mention Tiaris as a relative of Darwin’s finches, but instead said only that Darwin’s finches presumably evolved from a member of their ‘fourth group’’ of Emberizinae, which consists of 11 genera, including Volatinia as well as Tiaris; and (3) concerning the ‘‘other characters (anatomy, plumage, behav- iour)’’ noted by Baptista, the palatomaxillary character of Tordoff (1954a) and the skull window character of Bowman (1961) are the only published anatomical characters to ally Tiaris with Darwin’s finches, and both of these characters are also found in Vo- latinia and other emberizines. Additionally, the plumage pattern in primitive Darwin’s
283
finches is more closely matched by that in Volatinia than by that in any species of Tiaris, thus leaving only behavior as a possible link between Darwin’s finches and Tiaris. Until published accounts of behavior appear that carefully compare Darwin's finches with both Tiaris and Volatinia, the behavior of these birds cannot be evaluated accurately in taxonomic terms.
The history of the proposed relationships of Melanospiza to Darwin’s finches, already discussed in part, is very similar to that of Tiaris in its general lack of sub- stantiation. Without reason or comment, Cory (1892) listed the St. Lucia Finch as Geospiza richardsoni. Ridgway (1897) subscribed to a close relationship between Me- lanospiza and Geospiza, but mentioned only differences rather than similarities be- tween Melanospiza and Geospiza. Ridgway (1901:544-545) defines the similarities be- tween Melanospiza and Geospiza no further thana superficial ‘‘remarkable resemblance”’ and a ‘‘close . . . general resemblance,’’ leaving one to presume that black plumage in males is their main shared character. (The female plumage of Melanospiza, which was still unknown at the time of Ridgway’s writings, is not streaked as in Volatinia, Pinaro- loxias, and many of the Galapagos finches. It is solidly colored, largely brown above and buff below.)
Bond (1929:523), perhaps following Ridgway (1901), noted an undefined *‘remark- able, though superficial resemblance’’ to Geospiza in the male of Melanospiza, but maintained that the latter is ‘‘structurally close to Tiaris.”” Bond (1945, 1950, 1956) reported that Melanospiza is very similar to Geospiza, but provided no details. Tordoff (1954a, 1954b), following Bond (1950), theorized that Melanospiza and Geospiza could have evolved from a common ancestor. Bowman (1961:162) noted that the configura- tion of the horny palate in Geospiza fortis is nearly identical to that in Melanospiza. Bowman also reported a great diversity in palatal relief among Darwin’s finches, and because he did not characterize the palatal structure of other emberizines of similar size, it is not known if the resemblance in palatal relief in G. fortis and Melanospiza could be due to convergence associated with their similarity in bill size. Studies of the feeding habits of Melanospiza are lacking, and thus it is not possible to compare its feeding with that of any Darwin’s finches, many of which have been well studied in this regard. Bowman (1961:179, 201) also used the similar cranial pneumatization to suggest cautiously a relationship between Melanospiza and Darwin’s finches. Above I have noted that this character state cannot be used as evidence to unite Darwin’s finches with Tiaris and Melanospiza exclusive of Volatinia. Bowman (1963:135) gave no details in his mention of ‘‘a striking resemblance’’ of Melanospiza to G. fortis.
In summary, it appears that black plumage in males has been the character re- sponsible for most published accounts of the ‘‘remarkable”’ or *‘striking”’ resemblance of Tiaris and Melanospiza to Geospiza. The cranial pneumatization character of Bow- man (1961) is not unique to Tiaris, Melanospiza, and Darwin's finches. The similar horny palates of Melanospiza and G. fortis (Bowman, 1961) and the similarities in behavior between TJiaris and Geaspiza (Baptista, 1976) cannot be evaluated taxonom- ically until other emberizines, especially Volatinia, are included in the comparisons.
MATERIALS AND METHODS
Institutional abbreviations used: AMNH—American Museum of Natural History; ANSP—Academy of Natural Sciences of Philadelphia; CMNH—Carnegie Museum of Natural History; FMNH—Field Museum of Natural History; KU—University of Kan- sas Museum of Natural History; LSU—Louisiana State University Museum of Zool- ogy; UA—University of Arizona; UCMVZ—University of California (Berkeley) Mu- seum of Vertebrate Zoology; UMMZ—University of Michigan Museum of Zoology; USNM—United States National Museum of Natural History. Unless stated otherwise, all specimens listed below are from USNM.
Full skeletons or skulls examined in this study are as follows: Mniotiltinae—Den- droica petechia 502312, Geothlypis trichas 502315; Tanagrinae—Piranga rubra 492866,
284
Euphonia laniirostris 500551, Saltator maximus 500546; subfamily incertae sedis— Coereba flaveola 500532; Fringillinae (Carduelinae)—Carpodacus mexicanus 498536, Carduelis psaltria 499754; Drepanidini—Psittirostra cantans 298283; Icterinae—Mol- othrus aeneus 288959, Cacicus uropygialis 428586; Emberizinae—Spizella breweri UA 10001, 10002, 10004-10010, 11742, Pooecetes gramineus UA 2219, 6221, 8693, 13067, 13415-13418, Pipilo fuscus UA 6234, 8684, 8685, 8689, unnumbered, Phrygilus fruticeti 227537, Melanodera xanthogramma 491023, Poospiza nigrorufa 499056, Sicalis luteola 227533, Emberizoides herbicola 428724, Catamenia inornata 428755, Pezopetes capi- talis 429814, Passerina cyanella 492771, Sporophila_ nigricollis 500557, S. ameri- cana 500550, S. (=Oryzoborus) angolensis 428813, S. (O.) crassirostris 321748 (merger of Oryzoborus into Sporophila follows Olson, 1981), Melopyrrha_ nigra 322174, Loxipasser anoxanthus 502866, Tiaris bicolor 292670—292672, 487950, 487951, 488014, 488016, 488019, 488021, 488022, 488034, 500684, T. canora 226045- 226048, 320952, 320957, 322662, 343399, 343426, 343817, 498963498965, T. olivacea 289017, 291027, 291028, 292664, 292665, 292667, 292668, 318684, 318930, 318931, 428023, T. obscura 253464, Melanospiza richardsoni UMMZ 136174 (same specimen as examined by Bowman, 1961), Loxigilla noctis 487995, Volatinia jacarina splendens USNM 289016, 344324, 344325, 344926, 347234, 347235, KU 23689, 23691, 33218, 35306, 36598-36600, 37704, 37706, V. 7. peruviensis AMNH 8334, 9000-9009, 10235, 10236, LSU 70296, 84138, Pinaroloxias inornata 318774, 318775, 321071, 321072, Geospiza nebulosa (use of nebulosa to replace difficilis follows Sulloway, in press) UCMVZ 141033, G. fuliginosa UCMVZ 130299, USNM 345595, G. fortis UCMVZ 130248, G. magnirostris UCMVZ 130170, G. scandens UCMVZ 93115, G. conirostris UCMVZ 141044, Platyspiza crassirostris UCMVZ 93207, Camarhynchus psittacula UCMVZ 130414, C. pauper UCMVZ 141054, C. parvulus UCMVZ 130438, USNM 20533, C. palidus UCMVZ 130530, Certhidea olivacea UCMVZ 130567, USNM 345598. The specimens listed above form the main basis for my comparisons. However, from | to 7 additional skeletal specimens of most species of Darwin’s finches were used to verify certain characters. I also examined skins in the USNM collection of all species of Melanospiza, Tiaris, Volatinia, and Darwin’s finches, as well as all other genera of the Emberizinae.
To facilitate comparisons, descriptive nomenclature of the skull and mandible generally follows that of Bowman (1961). However, descriptions and comparisons of osteology and plumage are based solely upon my own examinations of specimens.
OsSTEOLOGICAL COMPARISONS
I compared | to 8 skeletal specimens of each species of Darwin’s finch (except Camarhynchus heliobates) with representative species of other groups of New World 9-primaried oscines (see MATERIALS AND METHops). All Darwin’s finches, both of the Galapagos and of Cocos Island, were found to resemble members of the Emberi- zinae and to differ from other 9-primaried oscines in the following characters: from Mniotiltinae—(1) relatively small ventral lobe of the ectethmoid, (2) relatively small nares, (3) narrow median ridge on the ventral surface of the premaxilla, (4) more acute angle at the jugal—-maxillary junction, (5) dentary much thicker than the surangular; from Tanagrinae—(1) broad transpalatine process, (2) small ectethmoid, (3) more acute angle at the jugal—maxillary junction, (4) ventral surface of the premaxilla less concave and without large mediolateral ridges; from Coereba flaveola (in response to Harris, 1972, 1974)—(1) broad transpalatine process, (2) small retroarticular process, (3) den- tary more curved and less pointed; from Fringillinae—(1) interorbital septum thinner (see Zusi, 1978), (2) interorbital area of the frontals narrower, (3) no extensive fusion of the prepalatine bar with the palatomaxillary process or the jugal, (4) nares oriented more laterad, (5) ventral surface of the premaxilla less concave, (6) retroarticular pro- cess large; from Drepanidini—(1) interorbital septum thinner (see Zusi, 1978), (2) no extensive fusion of the prepalatine bar with the palatomaxillary process or the jugal, (3) ventral surface of the premaxillary less concave; from Icterinae—(1) transpalatine process extending much posterior to the ectethmoid, (2) small retroarticular process,
285
(3) dentary more curved and less pointed. (I am not convinced of the monophyly of the ‘‘Cardinalinae.’’ For example, tanager-like cranial characters are present in Sal- tator and Cardinalis, while Passerina is emberizine-like in certain cranial features. Using the characters stated above, Saltator would have to be regarded as a thraupid, while Passerina would be an emberizine.)
Further evidence to support the allocation of Darwin’s finches in the Emberizinae is in Tordoff (1954a: Table 1), who found the *‘Geospizinae”’ not consistently different in any behavioral or morphological characters from the Richmondeninae (=Cardinali- nae), Emberizinae, or *‘Fringillinae’’ (=Fringilla), but substantially different from the Carduelinae and the Old World Estrildinae. In his own classification, Tordoff (1954a) lists Darwin’s finches in his expanded Fringillinae, which includes all genera that now are usually relegated to the Emberizinae. Recent classifications that do not recognize the distinctness of the Geospizinae and place Darwin’s finches in the Emberizinae are those of Paynter (1970), Sibley (1970), Morony et al. (1975), and Raikow (1978), al- though the definition of Emberizinae is not identical in each of these treatments.
Having concluded that Darwin’s finches indeed belong in the Emberizinae, the next step is to determine which emberizine is most similar morphologically and there- fore probably their closest relative. I compared the skulls and mandibles in any genus of emberizine that I suspected might be even remotely related to Darwin’s finches (see MATERIALS AND METHODs). No attempt was made to compare in detail the genera of “sparrows” (Zonotrichia, Aimophila, etc.) in the ‘‘first group’’ of Emberizinae of Paynter (1970) because these forms are very different from Darwin's finches in plumage and in their generally very large, bulbous squamosal region. Likewise, members of the second, sixth, and seventh “‘groups”’ of Emberizinae of Paynter (1970) are very dif- ferent in cranial osteology and in coloration and pattern of plumage from Darwin’s finches and tropical seed finches (the fifth and fourth ‘“‘groups’’ of Emberizinae, re- spectively, of Paynter), thus necessitating only a few comparisons.
The states of the characters below are careful, nonquantified observations, which are just as meaningful or better than quantified characters; many systematic problems simply are not readily solved by a quantitative treatment. Among the Galapagos finch- es, Geospiza nebulosa and G. fuliginosa have been suggested to.be the most primitive living species (Lack, 1945, 1946, 1947), a hypothesis supported by their generalized cranial morphology. The characters of these two species are therefore stressed in comparisons that follow. Details of the primitive nature of G. nebulosa and G. fuli- ginosa are found in EVOLUTION AND ZOOGEOGRAPHY.
In the comparisons below, if the skull or mandible of an emberizine species had an allometric character state that roughly matched that of a Geospiza of similar size (based on character states of G. nebulosa and the closely related series of G. fuliginosa, G. fortis, and G. magnirostris; see Fig. 1), then no evidence against a close relationship was produced. If, however, the character state of the skull or mandible did not resem- ble that of a Geospiza of similar size, this was taken as evidence against a close relationship to Galapagos finches. Some extrapolation was necessary when dealing with species smaller than any of the Geospiza.
I evaluated characters of Pinaroloxias independently from those of the Galapagos finches. Unlike in primitive species of Galapagos finches, the bill in Pinaroloxias 1s relatively thin and elongated, presumably correlated with its insectivorous, nectariv- orous, graminivorous, and frugivorous feeding habits (Smith and Sweatman, 1976). Also, because only one species of finch lives on Cocos Island, no directional allometric trends can be determined for Pinaroloxias, unlike the Galapagos finches. Nevertheless, Pinaroloxias closely parallels G. fuliginosa and G. nebulosa in its similarities and dissimilarities to various finches of the mainland.
As already demonstrated, Darwin’s finches and other emberizine finches share a suite of osteological characters that distinguish them from other groups of New World 9-primaried oscines. The osteological characters by which emberizine species differ from Darwin’s finches, both of the Galapagos and of Cocos Island, are as follows (characters in quotation marks are defined on pp. 205-206 of Bowman, 1961; abbre-
286
FIGURE 1. Skulls in dorsal (1) and lateral (II) aspect. A. Geospiza magnirostris UCMVZ 130170. B. G. fortis UCMVZ 130248. C. G. fuliginosa UCMVZ 130299. D. Volatinia jacarina peruviensis AMNH 9007. All Geospiza are from Isla Santa Cruz, Galapagos. Obvious allometric changes associated with increasing overall size include: dorsal view—larger attachment of temporal muscle, wider interorbital and internarial areas; lateral view—greater ossification of interorbital septum, stouter jugal bar, decreased slope of frontals, decreased relative size of nares, larger and more perpendicularly oriented bill. All figures are OSX.
viated geographical ranges are: CA = Central America; SA = South America; WI = West Indies): Phrygilus fruticeti (SA)—nares large and elongate, transpalatines ex- panded laterad, interorbital area narrow, “‘slope of upper mandible” small, dentary short; Melanodera xanthogramma (SA)—nares large, transpalatines and rostrum ex- panded laterad, rostrum with distinct sharp bend near anterior end of nares, auditory bullae large and bulbous, mandibular foramen large, “‘slope of lower mandible”’ large, posterior margin of dentary expanded laterad; Poospiza nigrorufa (SA)—nares oblong, transpalatines expanded laterad, ‘‘slope of upper mandible”’ small, maxillopalatine process located ventrally; Sicalis luteola (CA, SA)—prepalatine bar and transpalatine process expanded laterad, middle portion of jugal expanded dorsoventrad and com- pressed laterad, ‘‘slope of posterior border of surangular process”’ large; Emberizoides herbicola (CA, SA)—nares large and elongate, transpalatines protrude ventrad, “slope
287
of upper mandible’ small, ‘‘slope of nasal bone’’ small; Catamenia inornata (SA)— nares large, transpalatines expanded laterad, ‘slope of upper mandible”’ large; Pezo- petes capitalis (CA)—nares large and elongate, transpalatines expanded laterad, “‘slope of upper mandible’’ small, temporal fossa poorly developed, interorbital septum thin and foraminate; Sporophila nigricollis (CA, SA, WI) and S. americana (CA, SA)— dorsal surface of culmen decurved, palatines stout, transpalatines directed laterad, entire mandible stout with much lateral expansion at posterior margin of dentary, internal angular process large and tapers much (wide at base, narrow at distal end); Sporophila (Oryzoborus) angolensis (CA, SA) and S. (O.) crassirostris (CA, SA}— nares small (S. crassirostris only), rostrum stout and expanded laterad, palatines stout, transpalatines directed laterad, ‘‘slope of upper mandible”’ large, entire mandible stout with much lateral expansion at posterior margin of dentary, internal angular process large and tapers much (wide at base, narrow at distal end); Melopyrrha nigra (W1)— nares smail, dorsal surface of culmen decurved, transpalatines with a long thin pos- terior process, entire ectethmoid large, mandibular foramen small, posterior “‘slope of border of the surangular process’’ large; Loxipasser anoxanthus (WI)—dorsal surface of rostrum decurved, ‘‘slope of upper mandible’’ large, transpalatines with a long thin posterior process, entire ectethmoid large, posterior *‘slope of border of the surangular process’’ large, ‘‘slope of lower mandible”’ large; Tiaris bicolor (SA, WI)—“‘slope of upper mandible’’ large, transpalatine process long; T. canora (WI)—‘‘slope of upper mandible”’ large, transpalatine process long, entire ectethmoid large and bulbous, zy- gomatic process large; T. olivacea (CA, SA, WI)—"‘slope of upper mandible”’ large, rostrum with a distinct lateral protrusion where it meets jugal, transpalatine process long, entire ectethmoid large and bulbous, dentary short with posterior margin (at dentary—surangular junction) expanded dorsad and laterad; T. obscura (SA)—*‘slope of upper mandible” large, ventral lobe of ectethmoid large, flaring posteriad and laterad; Melanospiza richardsoni (W1)—nares large, ‘‘slope of upper mandible”’ small, trans- palatine process long and slender, palatomaxillary process long and narrow; *‘width of frontal bridge’’ small, ‘‘slope of lower mandible”’ large; Loxigilla noctis (W1)—tran- spalatine process thin, ‘‘slope of upper mandible”’ slightly small, ventral lobe of ect- ethmoid large, supraoccipital bulbous, “‘slope of lower mandible” large; Volatinia jacarina (CA, SA, WI)—no consistent differences noted.
Volatinia is clearly more similar than any other emberizine to Darwin’s finches in cranial osteology (see Fig. 1). However, I included grassquits of the genus Tiaris and the St. Lucia Finch (Melanospiza richardsoni) in additional, more quantitative com- parisons with Darwin’s finches because these birds have so often been mentioned as perhaps the closest living relatives of Darwin’s finches. I made 10 linear and 9 angular measurements of the skulls and mandibles of Melanospiza, Tiaris, and Volatinia, ex- actly as described in Bowman (1961:205—206) for Darwin’s finches, in an attempt to discover further evidence of the relationships of these genera to Darwin’s finches. These data are not presented here because of their apparent lack of useful systematic information, but are available on request. Spizella breweri, Pooecetes gramineus, and Pipilo fuscus were included for ‘‘out-group’’ comparisons. Within the Emberizinae, these three species are only distantly related to Melanospiza, Tiaris, Volatinia, or Geospiza and are thus expected to show differences from the latter group that cannot be attributed simply to allometric changes. When each linear measurement was plotted against the cube root of body weight, however, only Pooecetes and Pipilo were con- sistently different from the Galapagos finches in proportions of the skull and mandible, while all of the smaller species (Tiaris bicolor, T. olivacea, V. jacarina, and S. breweri) were generally very similar to Geospiza. (Body weights were not available for G. nebulosa or Pinaroloxias.) Plotted points that represent these smaller species were usually very near to regression lines based on the values for G. fuliginosa, G. fortis, and G. magnirostris, with no discernible trend to argue for or against a close relation- ship between Geospiza and any of the small species with which they were compared. Structural restraints may place severe limitations on cranial morphology in the smaller seed-eating emberizines, with the result that similar proportions are found in distantly
288
) 5 Cc Peete CM D FIGURE 2. Skins in ventral aspect. Geospiza fuliginosa (A—males, B—females). Volatinia jacarina pe-
ruviensis (C—males, D—females). Specimens are from ANSP, CMNH, FMNH, LSU, and USNM.
related forms. The relationship of linear measurements to body weight appears to be of little value in the search for potential relatives of Darwin’s finches.
The angular measurements of Pooecetes and Pipilo are often very different from those of species of Geospiza of a similar size, while these angles in Spizella often resemble those in Tiaris, Volatinia, G. nebulosa, or G. fuliginosa. Once again it is clear that certain ‘‘out-group’’ species may not differ strongly from “‘in-group”’ species in many quantitative characters. Nevertheless, the angular measurements of Spizella differ somewhat more from those expected of a small Darwin’s finch than do those of Volatinia. Keeping in mind that Volatinia and the species of Tiaris are smaller than G. nebulosa or G. fuliginosa, while Melanospiza is about the size of G. fortis, the angular measurements of Volatinia resemble those of Geospiza more than do those of Melanospiza or any species of Tiaris. The angular measurements of Pinaroloxias, however, are not clearly more similar to those of Volatinia or Tiaris, as they fall within the range of Volatinia and at least one species of Tiaris in every case except one.
I found only 3 characters in the postcranial skeleton that might shed some light on the relationships among Darwin’s finches, Volatinia, Tiaris, and Melanospiza. The humerus and ulna in all Darwin’s finches and in Volatinia are more delicate, especially in the slenderness of the shaft, than are those in Melanospiza or Tiaris. Also, the medial pneumatic fossa of the humerus in Darwin’s finches, 7. canora, and Volatinia is deeper than that in Melanospiza, T. olivacea, or T. bicolor. 1 found no characters shared between Darwin’s finches and Melanospiza or Tiaris that are lacking in Vola- tinia. These few postcranial characters lend support to the proposed very close rela- tionship of Volatinia to Darwin’s finches, and their apparent distinctness from Tiaris and Melanospiza.
289
0 5 ee CI
FIGURE 3. Skins in ventral aspect. Volatinia jacarina splendens (A, B—males; G, H—females). Pina- roloxias inornata (C, D—males; E, F—females). All specimens are from USNM.
NON-OSTEOLOGICAL CHARACTERS
Plumage.—Geospiza nebulosa, G. fuliginosa, G. fortis, and G. magnirostris (the species of Galapagos finches with seed-eating bills, black plumage in adult males, and streaked plumage in females) differ from Volatinia mainly in their larger body sizes, relatively shorter tails, larger bills, and duller black plumage in adult males. Rather similarly, Pinaroloxias differs from Volatinia in its larger body size, slightiy shorter tail, more elongate bill, and duller black plumage in adult males. None of these differ- ences warrants generic separation. The similarity in plumages among these species is apparent from Figures 2 and 3. Unlike in Tiaris and Melanospiza, the females of Volatinia, Pinaroloxias, and primitive species of Galapagos finches (G. nebulosa, G. fuliginosa) have streaked breasts and wing bars.
The pattern by which the adult male plumage is acquired in Galapagos finches is very similar to that in Volatinia jacarina peruviensis, the subspecies that occurs on the arid Pacific slope from southern Ecuador through Peru to northern Chile (which, incidentally, was originally described by Peale [1848] as Geospiza peruviensis). As illustrated in Figure 2, the area of the under-tail coverts is the last to attain black plumage in both V. j. peruviensis and G. fuliginosa. Fully black under-tail coverts seldom, if ever, occur in Darwin’s finches, and only very rarely in V. j. peruviensis. The under-tail coverts in adult males of other races of V. jacarina, however, are completely black, as is often the case in Pinaroloxias. Adult males of V. j. peruviensis further resemble Geospiza in that they are never as glossy in plumage as males of other races of V. jacarina. Of the 99 skins of males of V. j. peruviensis that I have examined, not one is blue-black, or even completely black, whereas adult males in other races of V. jacarina are normally completely blue-black.
No detailed study of molt is available for Pinaroloxias, but Lack (1945, 1947) noted that the males acquire the black plumage irregularly all over the body, instead of initially in the head region and then posteriorly, as in Galapagos finches. Males of V. j. splendens (the race that occurs, among other areas, along the Pacific coast from
290
northern México through central Ecuador) generally attain their black plumage in the same way as Pinaroloxias (Fig. 3). Thus the difference in the pattern and acquisition of black plumage in Pinaroloxias versus the Galapagos finches is paralleled in V. /. splendens versus V. j. peruviensis, and suggests that Pinaroloxias and the Galapagos finches evolved from different races of V. jacarina, namely from splendens and pe- ruviensis, respectively. Within V. jacarina, one of these conditions of plumage devel- opment is presumably primitive and the other derived, but I have no evidence for which is which. In this example, I see nothing wrong in suggesting ancestry of Pina- roloxias from V. j. splendens, and the Galapagos finches from V. j. peruviensis, based on shared characters, even though the shared character state in one of these groups is obviously primitive.
Life History.—The short, thin, buzzy song of Volatinia is reminiscent of that in various Darwin’s finches; a comparative analysis of songs in Volatinia versus its insular derivatives could be valuable, although vocalizations may be unreliable as indicators of generic relationships and are best used at the species level.
Volatinia is well known for its unusual song-flight, in which the reproductively active male jumps vertically (aided by the wings) while singing. Alderton (1963) found the height of these vertical maneuvers to vary from a norm of 30 to 45 cm up to 1.5 m. Vertical jumps are not necessarily accompanied by a song, nor the song with a jump. Such a flight display is absent in Darwin’s finches (and all other emberizines for that matter); it may have been secondarily lost. Nevertheless, Darwin’s finches have what may be a modified remnant of the song-flight of Volatinia. It is described by Lack (1945:23) as follows: ‘“‘The song is delivered from perches in the territory, also, in all except Certhidea [P. R. Grant (personal communication) has seen Certhidea singing in flight], during a special flight, slower with more rounded wings, usually descending from a higher branch to a lower. This song-flight is also common when going to or from the nest during display-building. In Cactospiza pallida, as in the other species, the song-flight is normally from one branch to another below the canopy of the forest trees. However, where this species occurs in the six to ten foot [1.8-3 m] scrub in the higher hills, the same movements result in an aerial song-flight above the low trees, which makes the bird conspicuous for a long distance.’’ The major differences in song- flights are the vertical movement accompanied by a jump in Volatinia versus the hor- izontal or diagonal movement without a distinct jump in Darwin’s finches (P. R. Grant, personal communication). These differences neither confirm nor refute the suggestion of homology in song-flights of Volatinia and Darwin’s finches.
Basic life history data are quite limited for Pinaroloxias, although the following passage from Slud (1967:292) suggests that, as in the Galapagos finches, it may still retain a modified song-flight: ‘‘Hundley observed (/oc. cit.): *. ..a black Cocos Finch with ruffled feathers was hopping up and down. The behavior of the female beside him was that of a young bird begging for food [and]. . . one black male only gave a sort of ‘‘chee’’ as it prepared to fly, and repeated 2 or 3 times as it flew away. ””
The nests of Galapagos finches are usually globular, domed structures with a side entrance (Lack, 1947), but open cup nests are occasionally built. The domed nest of Pinaroloxias appears to be similar, although descriptions are few (Slud, 1967). The nest of Volatinia is a small, open cup (Belcher and Smooker, 1937; Alderton, 1963; Bond, 1971), while Melanospiza and the species of Tiaris build globular nests with side entrances (Belcher and Smooker, 1937; Skutch, 1954; Bond, 1971). Globular nests are characteristic of the apparently related complex of West Indian finches that includes Loxipasser, Loxigilla, and Melopyrrha, as well as Melanospiza and Tiaris (Steadman and Olson, in preparation). Nest structure in these finches may vary intraspecifically, however, as Bond (1971) noted that both Loxigilla portoricensis and L. violacea build either cup-shaped or globular nests. Thus the normally globular nests of Darwin’s finches may have evolved independently after the initial colonization of Cocos Island and the Galapagos by Volatinia. An alternative hypothesis is that Volatinia originally built a globular nest and has evolved the use of a cup-shaped nest on the mainland since it colonized Cocos and the Galapagos.
291
The eggs of Darwin’s finches give no clear evidence of their affinities. Galapagos finches, Volatinia, and Tiaris all have lightly colored eggs that are spotted in various shades of brown or red. This is also apparently true of Pinaroloxias (Slud, 1967) and Melanospiza (Bond, 1971), although the ground color has not been specifically noted.
EVOLUTION AND ZOOGEOGRAPHY
The osteological discrepancies between Darwin’s finches and emberizines other than Volatinia are of a magnitude that precludes a relationship close enough to suggest potential ancestry. Lack (1945, 1946, 1947) suggested other characters of Geospiza fuliginosa, and especially of G. nebulosa, that are primitive within Galapagos finches; namely, black plumage in males, streaked underparts and a rufous wing-bar in females, a finch-like bill, a diet of seeds, and a habitat in the arid lowlands. Each of these characters is present in Volatinia, whose cranial morphology also resembles that in G. nebulosa and G. fuliginosa more than that in any other Galapagos finch.
Although Bowman (1961) claimed that Lack (1947) was unjustified in assuming that G. nebulosa or G. fuliginosa represents the most primitive living Darwin’s finch, Bowman did not himself clearly suggest which species may be primitive within the group, perhaps because of his reluctance to relate Darwin’s finches to any mainland birds. The fact that males of Volatinia are black supports the hypothesis of Lack (1945, 1947) on the primitiveness of black plumage in males of Darwin’s finches.
Volatinia, G. nebulosa, and G. fuliginosa all have finch-like bills adapted for seed eating, and not thin bills such as in Certhidea or Pinaroloxias. Like Tordoff (1954a:31), I disagree with Amadon (1950) in seeing **. . . no justification for considering a heavy, seed-crushing bill an evolutionary dead end.’’ Additional evidence for this view is found in the well substantiated conclusion of Raikow (1977) that the entire assemblage of Drepanidini evolved from a single species of Carduelinae with a finch-like bill.
I believe that the overall similarity of Pinaroloxias to the Galapagos finches can be attributed to the retention of primitive characters found in Volatinia, their probable common ancestor. Lack (1947:104) noticed the similarity in plumage between Pina- roloxias and Geospiza nebulosa and suggested that it presumably was due to the re- tention of primitive characters. Parallel evolution would account for the larger size and the reduction in glossiness of the black plumage in adult males of Pinaroloxias and G. nebulosa as compared to Volatinia. That the most primitive Darwin’s finches (Pina- roloxias, G. nebulosa, and G. fuliginosa) are larger than Volatinia is paralleled by other herbivorous vertebrates of the Galapagos, such as the tortoises (Geochelone) and the extinct giant thomasomyine rodent (Megaoryzomys), which are also larger than their nearest mainland relatives. As with Darwin’s finches, an increase in size in the tortoises and rodents probably enabled them to use a wider range of food plants.
That Pinaroloxias has been derived independently of the Galapagos finches makes sense zoogeographically. It has always perplexed me that Darwin’s finches would have colonized Cocos Island from the Galapagos or vice versa, a prerequisite for their supposed monophyly. Modern wind patterns (Alpert, 1963) are not favorable for such interisland movements, and Pleistocene wind patterns are not precisely known. It seems much more likely that the ancestors of both Pinaroloxias and the Galapagos finches came independently from the mainland rather than crossing some 600 km of open ocean between the Galapagos and Cocos Island, probably unaided by wind in either direction. Further, no other land birds from Cocos Island are more closely related to those of the Galapagos than to forms on the mainland, except possibly the Yellow Warbler, Dendroica petechia. The similar plumage of the Yellow Warbler of Cocos and the Galapagos, D. p. aureola, strongly resembles that of populations on certain West Indian islands, particularly the Lesser Antilles except Martinique. Olson (1980) has noted that D. p. aureola resembles D. p. peruviana of coastal Peru, Ecuador, and southern Colombia more than other mainland forms, and has suggested that the similarity between the Yellow Warblers of the West Indies and D. p. aureola may have evolved independently. Likewise, I believe that the similar plumage of D. p.
292
aureola on Cocos and the Galapagos may have evolved independently. As pointed out by Steadman and Ray (in press), it is not historically sound to hypothesize a close relationship between terrestrial vertebrates that are found in the Galapagos and the West Indies but not on the Neotropical mainland. The Panamanian water gap closed approximately 3 million years ago (Marshall, 1979), when the Galapagos were probably composed of only 2 or 3 very small islands which were farther from the mainland than today (Cox, in press) and were undoubtedly very active volcanically and without a well-developed flora to support terrestrial vertebrates. Porter (1976), following a mod- ern, comprehensive review of the flora of the Galapagos, concluded (p. 745): **. . . as the tropical American flora has become better known, most Galapagos species once thought to be only Mexican, Central American or West Indian in their extra-Galapa- gean distribution also have been found to occur in northern and western tropical South America. . . or to have been incorrectly identified . . . . West Indian relationships do not exist.
‘‘Ninety-nine per cent of the non-endemic vascular plant taxa in the Galapagos Islands also occur in South America. The remaining 1% occurs in Mexico and Central America. All but four of the 286 indigenous non-endemic taxa in the islands are known from the land area nearest the archipelago .... The endemics have their closest known relatives in South America as well.’’ My studies of the terrestrial birds and mammals of Galapagos agree with Porter (1976) in finding the nearest relatives in South America, not in the West Indies.
The Blue-black Grassquit occurs today essentially throughout the lowlands of the Neotropical region, including the Pacific slope from northern México to northern Chile. Thus nothing in its modern distribution presents any difficulty to the theory that it is the direct ancestor of both Pinaroloxias and the Galapagos finches. That Volatinia has some ability to disperse over water is shown by its occurrence on Grenada in the Lesser Antilles. Also, Clark (1905) reported an individual Volatinia landing on a ship midway between Trinidad and Grenada.
Neither the habitat nor mode of feeding in Volatinia differs from those of its insular counterparts in the Galapagos. Volatinia inhabits unforested areas such as grasslands, savannas, open brushlands, and all sorts of artificial clearings, where it feeds largely on seeds on or near the ground. Geospiza fuliginosa and G. nebulosa eat seeds and fruits, mainly on the ground (Bowman, 1961; Abbott et al., 1977), and live in the arid, scrubby lowlands of the Galapagos, although on larger, higher islands, G. nebulosa may be largely restricted to the humid, more densely forested uplands, at least during the nesting season. The accounts of Slud (1967) and Smith and Sweatman (1976) show that Pinaroloxias has a wide tolerance of habitat (cultivated areas to virgin forest), feeding heights (ground to the tops of trees), and food items (insects, nectar, seeds, fruits), thus providing few clues to the habitat and feeding ecology of its ancestor. The cranial morphology of Pinaroloxias, however, is clearly that of an emberizine, implying that its ancestor was a finch-like, largely seed-eating, ground-dwelling bird.
Because of recent geological evidence unavailable to earlier authors, Darwin's finches can now be put into a more meaningful chronological framework. Dalrymple and Cox (1968) reported three potassium-argon ages of about 2.0 million years for Cocos Island, cautioning that these ages are not necessarily the oldest potential ages for Cocos Island and do not certainly represent the actual time of emergence above the ocean. Cox (in press) has summarized the geochronology and paleogeography of the Galapagos, concluding that the oldest islands emerged 3 to 5 million years ago and were never linked to the mainland or to Cocos Island by a landbridge or a chain of islands, as suggested by many biologists in the past. In fact the Galapagos are moving toward South America and were farther from the mainland in the past than at present. The ancestral finch probably colonized the Galapagos significantly later than the initial emergence of barren basaltic rock, and probably only after an increase in land area and in the number of emergent islands (see the paleogeographic maps in Cox, in press). Also, the development of soil and some sort of structured vegetation was necessary for the successful emberizine invasions of the Galapagos and Cocos. In my opinion,
293
this occurred much later than the ages of the islands, themselves, particularly in light of the potential for very rapid evolution on islands. Certainly any suggestion of a colonization of these islands in the early or middle Tertiary Era is totally inconsistent with modern geological information. I would not be surprised if Cocos and the Gala- pagos were both totally without finches as recently as 100,000 years ago.
Generic Limits.—The generic status of Galapagos finches has been subject to much controversy. In the original description of most species of Galapagos finches, Gould (1837) recognized but a single genus, Geospiza, with Camarhynchus, Cactornis, and Certhidea as subgenera. Most subsequent workers have used 3-5 genera, although Rothschild and Hartert (1899, 1902) and Snodgrass and Heller (1904) recognized only Geospiza and Certhidea. Even those who use as many as 5 genera (Swarth, 1931; Lack, 1945; Bowman, 1961, 1963) generally have noted that one ‘‘genus”’ grades into the next, so that arbitrary limits must be made to split these finches into more than one genus. As a result, the various ‘“‘genera’’ are very difficult to define because they have few, it any, characters that distinguish them consistently from the other supposed genera. In addition, no species of finch in the Galapagos is clearly very distinct from all of the others. Nearly every species grades into one or two other species through specimens that are intermediate in size, plumage, and bill morphology. (For measure- ments and discussion of intermediate specimens, see Section I and Table 16 in Lack [1945], and pp. 23, 97-99 and Table XXXII in Lack [1947].)
Using the genera recognized by Bowman (1961), Geospiza grades into Platyspiza, which grades into Camarhynchus, while Camarhynchus grades into Cactospiza, which in turn grades into Certhidea. New evidence for the closeness of Platyspiza to Geo- spiza is provided by fossils from Isla Santa Cruz of a finch that is apparently inter- mediate between P. crassirostris and G. fortis (Steadman, 1981). Adult males of Platy- spiza can be very nearly as uniform black as in Geospiza (Swarth, 1931:211), while the extreme similarity in plumage between Platyspiza and Camarhynchus has long been recognized by many systematists. Likewise the plumage in Cactospiza is similar to that in Platyspiza and Camarhynchus, although showing some Certhidea-like ten- dencies. The Warbler Finch, Certhidea olivacea, is often considered the most *‘aber- rant’’ form of Galapagos finch, but it can be allied to Camarhynchus and Cactospiza through intermediate specimens from Isla Santa Cruz (Cactospiza “‘giffordi’’), Isla Floreana (Camarhynchus ‘‘conjunctus’’), and Isla San Cristobal (Camarhynchus *“‘au- reus’’), each of which was described by Swarth (1929) from one or two individuals. Lack (1945) and subsequent authors have not recognized these forms as distinct species, suggesting instead that they are either hybrids or freak individuals. Regardless, these specimens are clearly intermediate between Camarhynchus or Cactospiza and Cer- thidea in measurements of both the bill (see Swarth, 1931: Fig. 55) and the body, as well as in coloration of the plumage.
I do not agree with Bowman (1961:156) that the similarity of plumage in Platyspiza, Camarhynchus, and Cactospiza is the result of convergent evolution. If, as essentially all modern researchers agree, the Galapagos finches are a monophyletic group (i.e., all derived from a single ancestor), Bowman’s hypothesis would necessitate an initial divergence of plumages after colonization, followed by convergence. I cannot come up with a reasonable selective scheme to produce divergence and subsequent conver- gence in these plumages. Instead these finches seem clearly to be diverging both in plumage and in bill shape and size, into different habitats and life styles.
For example, although G. magnirostris and Certhidea are by themselves very different from each other, even these extremes can be united by a gradational series of intermediates. Further, the juvenal plumage of Certhidea is similar to that in other Galapagos finches, being olive-brown on the dorsum and vaguely streaked on the throat, breast, and upper belly. If G. magnirostris and Certhidea were the only finches in the Galapagos, one would almost surely assign them to a different genus. Their union through intermediate taxa and individuals, however, argues for congeneric status for Galapagos finches, as does their uniformity of breeding ecology and behavior. Thus I synonymize Camarhynchus Gould 1837, Certhidea Gould 1837, Cactospiza Ridgway
294
1897, and Platyspiza Ridgway 1897, with Geospiza Gould 1837. Because the Galapagos finches (Geospiza) are so similar in osteology and plumage to Pinaroloxias and Vo- latinia, | further regard Pinaroloxias Sharpe 1885, and Volatinia Reichenbach 1850, as synonyms of Geospiza Gould 1837.
I fully realize that this generic treatment will be controversial and may not be followed by many ornithologists, who would prefer instead to abide by the traditional generic limits of Swarth, Lack, and Bowman. With all respect to these and other researchers who have studied Darwin’s finches, I conclude that an objective survey of the anatomy of Darwin’s finches simply does not permit recognition of more than one genus. My treatment stresses the close relationship among these finches, which is masked by their maintenance in separate genera.
SUMMARY
Darwin’s finches have been the subject of a variety of systematic, evolutionary, and ecological studies since the time of Charles Darwin, yet there has never been a thorough attempt to determine their relationships to birds outside of Cocos Island and the Galapagos. On the basis of strong similarities in osteology and plumage, the Neo- tropical Blue-black Grassquit, Volatinia jacarina, appears to be so closely related to Darwin’s finches that I propose it to be the species that singly gave rise to the entire radiation of Darwin’s finches. Among all Darwin’s finches, the Cocos Finch (Pinaro- loxias) and the small Galapagos ground finches (Geospiza nebulosa, G. fuliginosa) are the most similar in plumage and osteology to V. jacarina. My review of other hypoth- eses of relationships of Darwin’s finches shows that no other proposed relative, in- cluding the often-mentioned Tiaris and Melanospiza, is as similar to Darwin’s finches as is Volatinia.
I believe that Volatinia colonized Cocos and the Galapagos independently from the mainland at some time late in the Quaternary Era. It is very unlikely that the Galapagos or Cocos would have been inhabitable by land birds before 1-2 million years ago, and the actual colonizations by Volatinia probably occurred even later. The close relationship of Volatinia to Darwin’s finches is further evidence for a South American derivation of the fauna and flora of the Galapagos, whose nearest relatives are not in the West Indies.
I regard Volatinia and all species of Darwin’s finches, both on the Galapagos and Cocos Island, to be members of a single, expanded genus Geospiza, since no single species or group of species within this assemblage is clearly distinct from any of the others.
ACKNOWLEDGMENTS
Since 1978, my interest in evolution of Darwin’s finches has been cultivated by three paleontological trips to the Galapagos Islands. These trips were funded by Fluid Research Grants from the Smithsonian Institution through S. Dillon Ripley and Storrs L. Olson; supplementary funds were provided by the Graduate Student Development fund, University of Arizona. I thank the staffs of Parque Nacional Galapagos (partic- ularly Miguel Cifuentes) and the Charles Darwin Research Station for permits and much other help in the Galapagos. For dedicated, long-term assistance in the field, I am indebted to James R. Hill, III, Miguel Pozo, and Edward N. Steadman. Shorter periods of field assistance were kindly provided by Camilo Calapucho, Maria José Campos, André De Roy, Gil De Roy, Steve Devine, Daniel Fitter, Jason Gallardo, David Graham, Sylvia Harcourt, Harvey Helman, Paul S. Martin, Mary Kay O’Rourke, Donna Reynolds, Robert Reynolds, and Arnaldo Tupiza. I appreciate the assistance provided by the staffs of the Division of Birds, Smithsonian Institution, and the Laboratory of Paleoenvironmental Studies, Department of Geosciences, University of Arizona, during various phases of museum research, funded by a Summer Visiting Student Fellowship from the Smithsonian Institution and a National Science Founda- tion Grant (DEB-7923840) to Paul S. Martin. The National Geographic Society pro-
vided funds for research at the British Museum (Natural History), where I enjoyed the cooperation of the staffs of the Departments of Ornithology, Mammalogy, and Paleon- tology. Marsha S. Cox, Bud Devine, and Tom Simkin have been very helpful in many aspects of my Galapagos work. I have benefitted much from discussions of passerine osteology and systematics with Helen F. James, Mary C. McKitrick, and Stonns, L: Olson, the last two persons having also criticized this manuscript. I also thank Robert I. Bowman, Joel Cracraft, Alan Feduccia, and Peter R. Grant for comments on this manuscript. Carmen A. Perez rendered the Spanish translation of the abstract. The photographs are by Victor E. Krantz. J. David Womble typed an early draft of the manuscript, Deborah Gaines typed two other drafts, while Martha Craig and Rosemarie Fiebig typed the final draft. Specimens were made available for study by Wesley E. Lanyon (AMNH), Kenneth C. Parkes (CMNH), John W. Fitzpatrick (FMNH), John P. O'Neill (LSU), Storrs L. Olson (USNM), Mary C. McKitrick (UA), Ned K. Johnson and Victoria M. Dziadosz (UCMVZ), Marion J. Mengel (KU), and Robert W. Storer (UMMZ). This is contribution number 330 of the Charles Darwin Foundation for the Galapagos.
LITERATURE CITED
Abbott, I., L. K. Abbott, and P. R. Grant. 1977. Comparative ecology of Galapagos ground finches (Geospiza Gould): evaluation of the importance of floristic diversity and interspe- cific competition. Ecol. Monogr. 47:151-184.
Alderton, D. C. 1963. The breeding behavior of the Blue-black Grassquit. Condor 65: 154-162.
Alpert, L. 1963. The climate of the Galapagos Is- lands. Pp. 21-44 In Galapagos Islands: a unique area for scientific investigations. Occ. Pap. California Acad. Sci. No. 44.
Amadon, D. 1950. The Hawaiian honeycreepers (Aves, Drepanididae). Bull. American Mus. Nat. Hist. 95:151-262.
Baptista, L. F. 1976. Handedness, holding and its possible taxonomic significance in grassquits, Tiaris spp. Ibis 118:218-222.
Beecher, W. J. 1953. A phylogeny of the oscines. Auk 70:270-333.
Belcher, C., and G. D. Smooker. 1937. Birds of the colony of Trinidad and Tobago. Part VI. Ibis, ser. 13 1:504-550.
Bock, W. J. 1963. [Review of] Morphological dif- ferentiation and adaptation in the Galapagos finches. Auk 80:202-207.
Bond, J. 1929. The rediscovery of the St. Lucian Black Finch. Auk 46:523-526.
. 1945. Check-list of birds of the West In-
dies. Acad. Nat. Sci. Philadelphia.
. 1948. Origin of the bird fauna of the West
Indies. Wilson Bull. 60:207—229.
. 1950. Check-list of birds of the West In-
dies. Acad. Nat. Sci. Philadelphia.
. 1956. Check-list of birds of the West In-
dies. Acad. Nat. Sci. Philadelphia.
. 1971. Birds of the West Indies. Boston,
Houghton Mifflin Co.
_ 1978. Derivations and continental affini- ties of Antillean birds. Pp. 119-128 In F. B. Gill (ed.), Zoogeography in the Caribbean. Acad. Nat. Sci. Philadelphia, Spec. Publ. No. 1132
Bowman, R. I. 1961. Morphological differentiation and adaptation in the Galapagos finches. Univ. California Publ. Zool. 58: 1-302.
. 1963. Evolutionary patterns in Darwin’s
finches. Pp. 107-140 In Galapagos Islands: a unique area for scientific investigations. Occ. Pap. California Acad. Sci. No. 44.
Clark, A. H. 1905. Birds of the southern Lesser Antilles. Proc. Boston Soc. Nat. Hist. 32:203- 312.
Cory, C. B. 1892. Catalogue of West Indian birds. Boston, C. B. Cory.
Cox, A. In press. Ages of the Galapagos Islands. In R. I. Bowman and A. E. Leviton (eds.), Patterns of evolution in Galapagos organisms. San Francisco, American Assoc. Adv. Sci., Pacific Div.
Dalrymple, G. B., and A. Cox. 1968. Palaeo- magnetism, potassium-argon ages and petrol- ogy of some volcanic rocks. Nature 217:323- 326.
Gould, J. 1837. [Remarks on a series of *‘ground finches’’ from Mr. Darwin’s collection, with descriptions of new species.] Proc. Zool. Soc. London, pt. 5:47.
. 1843. Descriptions of nine new species of birds collected during the recent voyage of H.M.S. Sulphur. Proc. Zool. Soc. London 11:103-106.
Gray, G. R. 1859. Catalogue of the birds of the tropical islands of the Pacific Ocean, in the collection of the British Museum. London, British Museum.
Harris, M. P. 1972. Coereba flaveola and the Geospizinae. Bull. British Ornith. Club 92:164— 168.
. 1974. A field guide to the birds of Gala- pagos. New York, Taplinger Publ. Co., Inc.
Lack, D. 1945. The Galapagos finches (Geospizi- nae): a study in variation. Occ. Pap. California Acad. Sci. No. 21.
. 1946. The names of the Geospizinae (Dar-
win’s finches). Bull. British Ornith. Club
67:15—22.
. 1947. Darwin’s finches: an essay on the
general biological theory of evolution. Cam-
bridge, England, Cambridge Univ. Press.
. 1961. Preface to the Torchbook edition [of
‘‘Darwin’s finches’’]. New York, Harper and
Bros.
296
Lowe, P. R. 1936. The finches of the Galapagos in relation to Darwin’s conception of species. Ibis, ser. 13 6:310-321.
Marshall, L. G. 1979. A model for paleogeography of South American cricetine rodents. Paleo- biology 5:126—132.
McDougall, I. 1979. Age of shield-building volca- nism of Kauai and linear migration of volcan- ism in the Hawaiian Island chain. Earth Planet Sci. Lett. 46:31-42.
Morony, J. J., Jr., W. J. Bock, and J. Farrand, Jr. 1975. Reference list of the birds of the world. New York, American Mus. Nat. Hist.
Muller, P. 1973. The dispersal centres of terrestrial vertebrates in the neotropical realm. The Hague, Dr. W. Junk B. V.
Olson, S. L. 1980. Geographic variation in the Yellow Warblers (Dendroica petechia: Paru- lidae) of the Pacific Coast of Middle America. Proc. Biol. Soc. Washington 93:473-480.
. 1981. A revision of the subspecies of Spo- rophila (‘‘Oryzoborus’’) angolensis (Aves: Emberizinae). Proc. Biol. Soc. Washington 94:43-S1.
Paynter, R. A., Jr. 1970. Subfamily Emberizinae. Pp. 3-214 In R. A. Paynter, Jr. (ed.), Check- list of birds of the world, vol. 13. Cambridge, Massachusetts, Mus. Comp. Zool., Harvard Univ.
Peale, T. R. 1848. United States Exploring Ex- pedition during the years 1838, 1839, 1840, 1841, 1842. Under the command of Charles Wilkes, U.S.N. Vol. HJ: Mammalia and or- nithology. Philadelphia, C. Sherman.
Porter, D. M. 1976. Geography and dispersal of Galapagos Islands vascular plants. Nature 264:745-746.
Raikow, R. J. 1977. The origin and evolution of the Hawaiian Honeycreepers (Drepanididae). Living Bird 15:95-117.
. 1978. Appendicular myology and relation- ships of the New World nine-primaried os- cines (Aves: Passeriformes). Bull. Carnegie Mus. Nat. Hist. No. 7.
Reichenbach, L. 1850. Avium systema naturale (Plate 79). Leipzig, F. Hofmeister.
Ridgway, R. 1897 (1896). Birds of the Galapagos Archipelago. Proc. U.S. Nat. Mus. 19:459- 670.
. 1901. Birds of North and Middle America, Part I. Bull. U.S. Nat. Mus. 50:1-715.
Rothschild, W., and E. Hartert. 1899. A review of the ornithology of the Galapagos Islands. With notes on the Webster-Harris Expedition. No- vit. Zool. 6:85—205.
, and . 1902. Further notes on the
fauna of the Galapagos Islands. Novit. Zool. 9:373-418.
Salvin, O. 1876. On the avifauna of the Galapagos Archipelago. Trans. Zool. Soc. London 9:447— 510.
Sharpe, R. B. 1885. Catalogue of the birds in the British Museum, vol. 10. London, British Mu- seum.
Sibley, C. G. 1970. A comparative study of the egg-white proteins of passerine birds. Bull. Peabody Mus. Nat. Hist., Yale Univ. 32:1 [Sie
Skutch, A. F. 1954. Life histories of Central American birds, Families Fringillidae, Thrau- pidae, Icteridae, Parulidae and Coerebidae. Pacific Coast Avifauna No. 31.
Slud, P. 1967. The birds of Cocos Island (Costa Rica). Bull. American Mus. Nat. Hist. 134:261-296.
Smith, J. M. N., and H. P. A. Sweatman. 1976. Feeding habits and morphological variation in Cocos Finches. Condor 78:244—248.
Snodgrass, R. E., and E. Heller. 1904. Papers from the Hopkins-Stanford Galapagos expe- dition, 1898-1899, XVI. Birds. Proc. Washing- ton Acad. Sci. 5:231-372.
Steadman, D. W. 1981. Vertebrate fossils in lava tubes in the Galapagos Islands. Proc. 8th In- tern. Cong. Speleo. 2:549-550.
_ and C. E. Ray. In press. The systematic position of Megaoryzomys curioi (Muroidea, Muridae) an extinct cricetine rodent from the Galapagos Islands, Ecuador. Smithsonian Con- trib. Paleobiol. No. 51.
Sulloway, F. J. In press. The Beagle collections of Darwin’s finches (Geospizinae). Bull. Brit- ish Mus. (Nat. Hist.), Zool. Ser.
Sushkin, P. P. 1925. The evening grosbeak (Hes- periphona), the only American genus of a pa- laearctic group. Auk 42:256-261.
Swarth, H. S. 1929. A new bird family (Geospi- zidae) from the Galapagos Islands. Proc. Cal- ifornia Acad. Sci., ser. 4, 18:29-43.
. 1931. The avifauna of the Galapagos Is- lands. Occ. Pap. California Acad. Sci. 18:1- 299:
Tordoff, H. B. 1954a. A systematic study of the avian family Fringillidae based on the struc- ture of the skull. Misc. Publ. Mus. Zool. Univ. Michigan No. 81.
. 1954b. Relationships in the New World nine-primaried oscines. Auk 71:273-284. Zusi, R. L. 1978. The interorbital septum in car- dueline finches. Bull. British Ornith. Club
98:5—10.
Laboratory of Paleoenvironmental Studies, Department of Geosciences, University of Arizona, Tucson, Arizona 85721 USA; present address: Division of Birds, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560 USA.