Homeomorphy in Recent Deep-Sea Brachiopods SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY t NUMBER 11 SERIAL PUBLICATIONS OF THE SMITHSONIAN INSTITUTION The emphasis upon publications as a means of diffusing knowledge was expressed by the first Secretary of the Smithsonian Institution. In his formal plan for the Insti- tution, Joseph Henry articulated a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This keynote of basic research has been adhered to over the years in the issuance of thousands of titles in serial publications under the Smithsonian imprint, com- mencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: Smithsonian Annals of Flight Smithsonian Contributions to Anthropology Smithsonian Contributions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Studies in History and Technology In these series, the Institution publishes original articles and monographs dealing with the research and collections of its several museums and offices and of profes- sional colleagues at other institutions of learning. These papers report newly acquired facts, synoptic interpretations of data, or original theory in specialized fields. These publications are distributed by mailing lists to libraries, laboratories, and other in- terested institutions and specialists throughout the world. Individual copies may be obtained from the Smithsonian Institution Press as long as stocks are available. S. DILLON RIPLEY Secretary Smithsonian Institution SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY NUMBER 11 G. Arthur Cooper Homeomorphy in Recent Deep-Sea Brachiopods SMITHSONIAN INSTITUTION PRESS CITY OF WASHINGTON 1972 ABSTRACT G. Arthur Cooper. Homeomorphy in Recent Deep-Sea Brachiopods. Smithsonian Contributions to Paleobiology, number 11, 25 pages, 5 figures, 4 plates. 1972.—A col- lection of brachiopods from the Baja California Abyssal Plain forms a deep-sea assemblage unusual in that it contains three genera that are unrelated but externally almost identical; i.e., they .are homeomorphs. One is Neorhynchia, an impunctate rhynchonellid; the second, a punctate terebratulid with short loop, is called Abysso- thyris; and the third is referred to a new genus, Notorygmia, related to Macandrevia. A discussion of homeomorphy is followed by the systematics of the genera and species involved. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1972 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 50 cents (paper cover) Contents Introduction 1 Homeomorphy 1 Sulcation 3 Locality data 4 Baja California Abyssal Plain 4 West-southwest of Cortes Bank 5 Off Central California, South of Davidson's Seamount 5 Off Baja California 5 Antarctica 5 Systematics 5 Neorhynchia strebeli (Dall) 6 Neorhynchia profunda, new species 6 Abyssothyris elongata, new species 9 Notorygmia, new genus 13 Notorygmia diamantina (Dall) 13 Notorygmia abyssa, new species 14 Waldheimia (?) wyvillei (Davidson) 15 Appendix 15 Pelagodiscus atlanticus King 15 Literature cited 15 G. Arthur Cooper HomeOIIlOrphy 111 ReCeilt Deep-Sea Brachiopods Introduction The collection that forms the subject of this paper was sent to me by Mr. Spencer R. Luke of the Aquarium Museum, Scripps Institution of Oceanog- raphy, La Jolla, California. Most of the material was collected by Professor Carl Hubbs and collaborators of the Scripps Institution whose work was supported by NSF Grants Nos. GBS 13319 and GS 1300. Per- mission to describe the material was kindly granted by Dr. William A. Newman. I am grateful to all of these men for their generosity in permitting this study and for permitting retention of the type speci- mens and study set in the national collection. These specimens and those retained by Scripps constitute the finest collection of abyssal brachiopods yet made. Thanks are given to Dr. Helen McCammon, Field Museum of Natural History, Chicago, and to Dr. Richard E. Grant for critically reviewing this paper. Their suggestions proved helpful and valuable. Thanks are also due to Mr. Lawrence B. Isham, visual information specialist at the National Museum of Natural History for his fine drawings of the lophophore of Neorhynchia and Abyssothyris. Homeomorphy Homeomorphy, or convergence of exterior form, in Recent brachiopods occurs in three unrelated genera inhabiting the Baja California Abyssal Plain off the coast of California. Association of these genera is not confined to the Baja California Abyssal Plain but has been identified in the Pacific south of Cali- fornia to the Antarctic. The associated genera are Abyssothyris, Neorhynchia, and Notorygmia (a new G. Arthur Cooper, Department of Paleobiology, Smith- sonian Institution, Washington, D. C. 20560. genus for the species hitherto identified as Macan- drevia diamantina Dall). The homeomorphy ex- hibited by Abyssothyris and Neorhynchia was de- scribed by Muir-Wood (1960). The example from the Baja California Abyssal Plain is more remarkable because it involves three genera having almost iden- tical external form and representing two orders and three superfamilies of brachiopods. So precise is the homeomorphy that the first two genera were mis- taken and described under the name Terebratula wyvillii by Thomas Davidson (1878), a usually as- tute observer and the most widely informed brachio- pod worker of the last century. Homeomorphy is common among the brachiopods and has attracted considerable attention. Examples from the Paleozoic Era have been described by Cooper (1930), Ulrich and Cooper (1936), and Bell (1938); and from the Mesozoic by Cloud (1941) and Buckman (1901, 1906). Cooper (1970, p. 238) indicated homeomorphy in Tertiary and Recent brachiopods. Mimicry of external form in the brach- iopods often is so deceptive that it has led to diffi- cult problems in classification and identification. The confusion created by homeomorphy is nowhere bet- ter shown than that revealed by Muir-Wood in Abys- sothyris and Neorhynchia. Although this astute worker was aware of the pitfalls of homeomorphy, the third member of the trio mentioned above escaped her. Abyssothyris was proposed by Thomson (1927, p. 190) for the deep-sea species Terebratula wyvillii Davidson (1878) taken from collections made by the Challenger Expedition. Specimens were taken from depths ranging from more than 6,000 feet (1,830 m) to deeper than 17,000 feet (5,183 m). The species was named after Wyville Thomson, and the name was later corrected to T. wyvillei (Thom- 1 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY son, 1927, p. 199). In studying Davidson's described and figured specimens in the British Museum (Nat- ural History), Muir-Wood discovered that another species, Neorhynchia strebeli (Dall), was misidenti- fied by Davidson as T wyvillei. Davidson's speci- mens all came from the Southern Hemisphere off Australia, the Falkland Islands, and Chile. Neorhynchia also was named by Thomson (1915, p. 388), who selected Hemithyris strebeli Dall from the mid-Pacific as the type species. These two brach- iopods, A. wyvillei and N. strebeli, share a feature— their sulcate anterior commissure—that makes them similar in appearance and has caused the confusion between the genera. These brachiopods are anteriorly folded toward the ventral side; thus, the ventral valve has a marked median fold, and the dorsal valve has a median sulcus of varying depth. In a survey of the brachiopods in the National Museum, Dall (1920) designated type localities for each of the species. This was done in ignorance of the generic composition of the lots taken from some of the named localities. In the case of Terebratula (Abyssothyris) wyvillei, Dall (1920, p. 321) stated: "As Davidson appears to have selected no special locality among those he enumerates in the Challenger Report, I choose station 299, off Valparaiso, Chile in 2160 fathoms [12,960 feet], gray mud, bottom temperature 34°F." Not realizing the role that home- omorphy can play in such matters, Dall inadvertently selected a locality where specimens of Neorhynchia misidentified by Davidson as Abyssothyris occur. Also taken at this station was another brachiopod, Waldheimia wyvillii Davidson, which will be referred to later. Muir-Wood (1960, p. 523) states: Unfortunately the only specimens preserved from here [Challenger station 299] are both Neorhynchia, one of which was figured by Davidson in 1880 (pi. 2, figs. 8, 8a), also in 1886 (pi. 2, fig. 9), no. ZB 1161 as T. [Terebratula, the generic name used by Davidson] wyvillei [Muir-Wood over- looked the occurrence of Waldheimia wyvillii at the same station]. If Dall's selection is to be accepted then the type specimen of Terebratula wyvillei is a rhynchonellid and Abyssothyris would have to be replaced and become a synonym of Neorhynchia. Abyssothyris wyvillei would be- come Neorhynchia wyvillei. The terebratulid Abyssothyris sens. str. would be left without either a generic or specific name and would have to be renamed. Muir-Wood further points out that the question of inclusion of a type locality in the description of a new species was not embodied in the new Inter- national Code of Zoological Nomenclature. She also indicates that inasmuch as "Dall's selection was made in 1920 and that the rules of that date did not pro- vide for the definition of a nominal species by ref- erence to a type locality, the selection can be set aside, and a lectotype chosen from another Chal- lenger Station." This recommendation was followed by the designation of specimen ZB 1160 (from Chal- lenger station 160 at 2,600 fathoms) as the lecto- type.1 The type thus fixed is wider than long and has a narrow, deep fold on the ventral valve and a nar- row, deep sulcus on the dorsal valve. The lectotype measurements, in millimeters (taken from Muir- Wood, 1960, pi. 7, figs. 5a-c), are as follows: length 12.5, width 14.5, and thickness about 8.0. A second specimen (Muir-Wood, 1960, pi. 7, figs. 3a-c) has the following measurements: length 12.7, width 12.7, and thickness 8.0. Thus, the specimens are slightly wider than long or are equal in length and width, quite unlike those from the Baja California Abyssal Plain that are described below. An immature speci- men illustrated by Muir-Wood (1960, pi. 7, fig. 1) is slightly longer than wide: length 10.5 mm and width 9.5 mm. Specimens of Neorhynchia misidentified by David- son as Terebratula wyvillii were taken by the Chal- lenger at station 184 south of New Guinea at 1,400 fathoms and at station 299 off Valparaiso, Chile, at 2,160 fathoms. A specimen from the former locality is 15 mm long by 16.5 mm wide, representing a shell with width greater than the length. The sulcus is broad and shallow and the fold low. Study of the specimens submitted by Scripps Insti- tution complicates matters still further. Comparison of the types of Terebratula wyvillii, Hemithyris {Neorhynchia) strebeli Dall, and Macandrevia (No- torygmia) diamantina with the specimens from the Baja California Abyssal Plain indicates that the latter are not the same as Davidson's and Dall's species. When plotted with the large collection of Neorhyn- chia from the Baja California Abyssal Plain, the specimen of N. strebeli falls entirely outside the range of variation of the largest California speci- mens. Examples of Macandrevia diamantina from off Cocos Island, west of Panama, the type locality, 1 Article 16(b) of the 1961 edition of the International Code of Zoological Nomenclature adopted by the XV International Congress of Zoology specifically rules out mention of a type locality as an "indication" in establishing a type species. NUMBER 1 1 are yellow, flat, and expanded, whereas specimens from the Baja California Abyssal Plain are trans- lucent white, very deep, and elongated. Other speci- mens of this sulcate type of Macandrevia from loca- tions farther south and in Antarctic seas are similar to the California specimens rather than to those from off Cocos Island. Abyssothyris wyvillei, primarily a southern species, is deeply sulcate and wider than long. Dall's specimens identified as A. wyvillei from southwest of the Galapagos are not like Davidson's specimens, nor are they close to those from the Baja California Abyssal Plain. We do not have collections large enough from Dall's localities or other areas yielding these three genera to discover the relation- ship of these species to those from the Baja California Abyssal Plain. All of the scattered specimens of these three genera are more like those of the Baja California Abyssal Plain than they are like Dall's and Davidson's type specimens. Sulcation The majority of articulate brachiopods (class Arti- culata) have a median fold—a device thought to facilitate filter feeding—separating the incoming streams with food from the excurrents bearing body waste. So many brachiopods are folded toward the dorsal side in the adult condition that this is re- garded as normal for articulate brachiopods. Folding in the opposite direction—toward the ventral side, the ventral valve having a fold and the dorsal valve an opposing sulcus—is rare in the adult condition of the articulate brachiopod. Among early brachio- pods many are ventrally folded in the young, but folding direction reverses in growth, and the more usual condition of uniplication, the dorsal valve with fold, is established in the adult. Heterochronous homeomorphs of Abyssothyris and Neorhynchia have existed since Silurian time. Of impunctate brachio- pods, Brachymimulus, a member of the Triplesiacea, has a form almost identical to that of Neorhynchia, but it has a long, forked cardinal process and en- tirely different ventral beak structures. In the Mis- sissippian the rhynchonellid Sanjuania is similar in shape to Neorhynchia, as is Paranorella of the Per- mian. Camarophorina is a smooth, sulcate steno- scismatacean from the Permian identical in form to Neorhynchia, Brachymimulus, and Sanjuania. No- rella is a sulcate rhychonellid of the Triassic. Thus, homeomorphs of Neorhynchia have existed since the Silurian. A similar series of heterochronous homeomorphs exists among the punctate brachiopods and dupli- cate the exterior form of Abyssothyris and Notoryg- mia. In the Permian, Cryptacanthia and Glossothy- ropsis are almost identical homeomorphs of the two modern genera. The loop of Glossothyropsis is like that of Notorygmia but it does not have a septal pillar in the initial stages of its development. Nu- cleata, Nucleatula, and Dinarella are short-looped punctate forms from the Mesozoic that ape Abys- sothyris. In the Pliocene of the Mediterranean region "Terebratula" meneghiniana Seguenza, because of its sulcate commissure, has been referred to Abys- sothyris (Muir-Wood, 1960, p. 524; Thomson, 1927, p. 201) even though its interior has not been analyzed. Of some interest in the Permian is an association like that of Abyssothyris and Neorhynchia. In the black shale and limestone of the South Wells Mem- ber of the Cherry Canyon Formation, Paranorella, a sulcate rhynchonellid, occurs with Glossothyropsis, a long-looped terebratulid. The fact that the homeomorphs of the Baja California Abyssal Plain are deep-water dwellers and that these genera are in deep water wherever found suggests that sulcation may be a phenomenon of deep water. This suggestion might also hold for the association of the homeomorphs Paranorella and Glossothyropsis in the Permian. The South Wells Member, in which this association occurs, is regarded in some quarters as of deep-water origin, but not abyssal as in the modern examples under discussion. Unfortunately for this idea, sulcation is not confined in modern brachiopods to the abyss or even to moderately deep waters. Shallow-water, sulcate genera are fairly common: Terebratella, Magellania, Tere- bratalia, and Waltonia to name the most conspicu- ous ones. Some of these, such as the last two, actually may live in the tidal zone. Among the fossil forms noted above, none save possibly Para- norella and Glossothyropsis can be connected with a deep-water environment. Glossothyropsis is fairly common in some normal marine environments that definitely can be identified as shallow water. This is true also of the Silurian and Mesozoic homeomorphs mentioned above whose associates and paleogeog- raphy indicate shallow-water environment. What- ever the evolutional pressure toward sulcation, it apparently is not great depth of water. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Locality data BAJA CALIFORNIA ABYSSAL PLAIN LOCALITY S 1070-22.—Latitude, 31° 19.7' N to 31°08.2' N; longitude, 119°39.2' W to 119°35.5' W. Depth, 3,601 to 3,687 m; 25-foot otter trawl. R./V Melville. Collectors: C. Hubbs, R. Wisner, S. Luke; December 18, 1969. The material from this collection, received in early 1970, consisted of 147 specimens of Abyssothyris elongata, 108 of Neorhynchia profunda, 8 of Noto- rygmia, and 4 of Pelagodiscus. The percentage rela- tionship of the homeomorphs—Abyssothyris, 55 per- cent; Neorhynchia, 42 percent; and Notorygmia, 3 percent—compares favorably to the associations seen at localities Mv 70—III-6 and Mv 70—III—8 but not with the collection from west-southwest of Cortes Bank. This is the only sample with a fair supply of young specimens of Abyssothyris and Neorhynchia. LOCALITY MV 70-111-3.—Latitude, 31°24.0' N to 31°28.8' N; longitude, 120°14.5' W to 120°10.3' W. Depth, 3,880 m; 25-foot otter trawl. R./V Melville. Collectors: R. Wisner, F. Rokop, and S. Luke; March 21, 1970. This collection, the smallest studied, numbers only 15 specimens: 4 of Abyssothyris, 1 of Notorygmia, 7 of Neorhynchia, and 3 of Pelagodiscus. The latter are attached to rock and soft tarry material (Emery, 1960, p. 322). This is the only locality in which Neorhynchia outnumbered Abyssothyris. LOCALITY MV 70-III-6.—Latitude, 31°36.0' N to 31° 14.4' N; longitude, 120°07.4' W to 120°09.6' W. Depth, 3,706-3,806 m; 25-foot otter trawl. R./V Melville. Collectors: R. Wisner, F. Rokop, and S. Luke; March 23, 1970. A total of 314 specimens were taken here: 188 of Abyssothyris, 120 of Neorhynchia, 3 of Notorygmia, and 3 of Pelagodiscus. The percentage relationship of the homeomorphs—60 percent Abyssothyris, 39 per- cent Neorhynchia, and 1 percent Notorygmia—is like that of localities S 1070-22 and Mv 70-III-8. Some of the specimens were attached to soft, tarry "pebbles." LOCALITY MV 70-III-8.—Latitude, 31°47.5' N to 32°00' N; longitude, 120° 19.0' W to 120° 18.0' W. NEV. 1 I J UTAH ! C ° LO. ! \ SAN (DFRANCI \ SCO N \ \ \ CALIF. \ U 1 - 35* 1 SI067-I03 \ANGF.LES j ARIZ. 1 N./M. V- — •* - Sl067-547# \B C Jr^""- so- ss* MV-70-IM-1 3,6,6 ^SI070-22\ ( "^N "* _-l_l \ MEXICO • MAa V • J1 6 5 4 * 3 ■*■ 2 1 UJ z I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 Wl DTH FIGURE 5.—Scatter diagram showing the length/width (dots) and thickness/width (crosses) relationships of Abyssothyris elongata, new species, from loc. S 1070-22. Triangle a top indicates length/width of A. wyvillei. general rule the smaller specimens are rectimarginate or nearly so and the larger ones usually are more strongly sulcate. USNM 550398p (Plate 4: figures 24—26) is a large adult with rectimarginate anterior commissure. A strongly nasute, narrow specimen in the same lot is USNM 550398r (Plate 4: figures 15—17). A strongly folded but wide specimen is USNM 550400a (Plate 4: figures 5-8). From lo- cality S 1070-22, specimen 550397o (Plate 4: fig- ures 43—46) is a large rectimarginate individual, but specimens 550397n (Plate 4: figures 38-41) and 550397q (Plate 3: figures 30-33) are narrowly elongate and nasute. Variation in the loop appears to be a function of age and calcification of the specimens. A few individ- uals have much wider transverse bands than usual (USNM 550398i) but the loop is remarkably uni- form in its characteristic features: shortness, and rounded anterolateral extremities. The median flexure of the transverse band is variable, stronger and sharper in some specimens than others, but always present. The crural processes vary from blunt and rounded to long and acute. Young specimens do not have a readily recognizable cardinal process, but in large, old individuals such as USNM 550398x (Plate 3: figure 25) it is a large boss with ragged edge. NUMBER 1 1 13 Suborder TEREBRATELLIDINA Muir-Wood, 1955 Superfamily TEREBRATELLACEA King, 1950 Family DALLINIDAE Beecher, 1893 Notorygmia, new genus Macandrevia Thomson, 1927, p. 239 (part). DESCRIPTION.—-Moderately large, somewhat dia- mond-shaped to pentagonal in outline; valves un- equal in depth, the ventral valve deeper than the dorsal valve; shell usually thin, yellowish or white, and translucent to transparent; beak suberect; fora- men large, elongate, but open anteriorly; deltidial plates rudimentary or absent. Surface marked only by concentric growth lines. Punctae very fine but not crowded. Pedicle valve interior with strong teeth buttressed by short dental plates. Dorsal valve with strong socket ridges and small outer hinge plates. Crural bases supported by short sloping plates (inner hinge plates?) that meet the valve floor to bound a narrow notothyrial cavity. Loop long, free in adults, with short posterior crural processes and narrow descend- ing and ascending branches; anterior junction of branches with short, delicate spines. TYPE SPECIES.—Notorygmia abyssa, new species. DICUSSION.—Internally, Notorygmia is exactly like Macandrevia in having plates (inner hinge?) attach- ing the crural bases to the valve floor. The loop is exactly like that of Macandrevia, and its develop- mental stages are known from two immature speci- mens of Macandrevia [Notorygmia] diamantina Dall described and figured by Jackson (1912, p. 380). The smallest individual showed the descending branches attached to a septal pillar and the presence of a small hood. The next larger stage revealed rem- nants of the processes that attached the loop to the septum in the terebrataliform loop stage. The character that sets this shell apart from other macandrevias is the strong sulcation of the anterior commissure. All other species of Macandrevia are rectimarginate or nearly so. A new species from the west coast of Africa actually shows a slight tendency toward sulcation but otherwise most specimens of all other species are rectimarginate. Strong sulcation is the homeomorphic character that confuses this genus with Abyssothyris and Neorhynchia. The confusion with the former is stronger because both genera are punctate. Notorygmia is a widely distributed brachiopod, ranging from latitude 31° north, in the Baja Cali- fornia Abyssal Plain south to the Gulf of Panama, and to latitude 56° south and longitude 156° west and finally to a point off Queen Mauds Land, Ant- arctica (Jackson, 1912). This vast expanse of sea is essentially the same as that in which Abyssothyris and Neorhynchia range. Throughout this region these genera are usually taken from great deeps. In any assemblage containing all three homeo- morphs, Notorygmia is readily distinguished from Neorhynchia by its punctate shell and lack of delti- dial plates; it differs from Abyssothyris, also punctate, in its suppression of deltidial plates and the presence of a long, recurved loop. The name of this new genus derives from the Greek notos (back) and orygma (trench). Notorygmia diamantina (Dall) PLATE 2: FIGURES 30-38. Macandrevia diamantina Dall, 1895, p. 723, pi. 30, fig. 5; pi. 32, figs. 3, 6; 1908, p. 455.—Thomson, 1918, p. 34 (part) ; 1927, p. 240 (part). Examination of Dall's type specimens of Macan- drevia diamantina reveals significant differences be- tween them and specimens taken from off Baja Cali- fornia and even south to the Antarctic. Dall's types and two additional specimens from southeast of Cocos Island, Gulf of Panama, and one specimen from off Sechuca Point, Peru, are notable for their slender lateral profile and nearly equal length and width. Compared to specimens of Notorygmia from off California and Baja California that are deep and strongly elongated, the differences become striking. Measurements (in millimeters) of Dall's specimens are as follows: Dorsal Maxi- USNM valve mum Thick- Apical L/W specimen Length length width ness angle ratio 122860a (type) 18.1 16.0 17.3 8.1 97° 1.05 122860b (paratype) 16.1 14.5 16.2 6.8 103° 0.99 110743 13.4 11.9 12.4 5.5 105° 1.08 223627 15.6 13.8 14.8? 6.2 100° 1.05 TYPES.—Lectotype: USNM 122860a. Figured paralectotype: USNM 122860b. DISCUSSION.—It is interesting that two species of Macandrevia occur off Cocos Island—M. craniella 14 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Dall and M. americana Dall. Both occur in deep water, the latter at 1,175 fathoms (2,149 m) and the former at 1,672 fathoms (3,059 m). Macandrevia craniella was found with N. diamantina. Both M. craniella and M. americana are rectimarginate and in every way normal for Macandrevia. This reiterates the point previously made that sulcation appears not to be confined to brachiopods in abyssal waters. See also discussion (below) of Waldheimia wyvillei Davidson. Notorygmia abyssa, new species PLATE 2: FIGURES 23-29; PLATE 3: FIGURES 1-19. Macandrevia diamantina Jackson (not Dall), 1912, p. 379, pi. 2, figs. 15-19.—Thomson, 1927, p. 240 (part).— Hertlein and Grant, 1944, p. 157 (part). Macandrevia coatsi Jackson.—Helmcke, 1939, p. 251. DESCRIPTION.—Elongate-oval in outline, with max- imum width near midvalve; sides rounded; anterior nasute; posterolateral margins forming angle of 85°. Shell thin, translucent, glossy but with traces of a light brown periostracum. Anterior commissure strongly sulcate, producing an anterior projection of the ventral valve. Ventral valve with the umbo moderately convex and the anterior half nearly flat in lateral profile; strongly and somewhat narrowly domed in anterior profile, the crest of the dome narrowly rounded; sides sloping steeply. Fold originating posterior to mid- valve but broad and gentle, narrowing anteriorly. Dorsal valve evenly and gently convex in lateral profile but broadly and gently convex in anterior pro- file and with the median region narrowly sulcate. Sides narrowly rounded, slopes precipitous. Sulcus barely visible at midvalve, but deepening anteriorly to become a moderately deep and narrow groove; tongue long and narrowly rounded. Measurements in millimeters: Dorsal USNM valve Thick- Fold Apical specimen Length length Width ness width angle 550402a 19.6 18.0 16.9 11.6 11.6 85° 550402b 19.8 18.0 16.8 11.0 9.3 88° 550406 22.7 19.7 19.1 12.0 10.4 87° 549762 17.3 15.7 15.8 p 11.2 92° 550404a 19.1 p 16.5 9.1 10.0 86° 550404b 18.4 16.4 15.0 8.8 9.3 90° 550403 12.8 11.3 12.0 5.3 5.8 107° 550405 16.0 14.6 15.0 6.6 7.8 101° 550105 14.7 13.4 13.1 6.4 8.0 105° DIAGNOSIS.—Elongate, narrow, and deep Notoryg- mia with strong sulcus. LOCALITIES.—SV 1066-547; S 1070-22; Mv 70- III-6; Mv 70-III-8; Mag Bay Exped. Sta. A27; Eltanin Cruise 25 Sta. 364. TYPES.—Holotype: USNM 550402b. Figured par- atypes: USNM 550402a, 550404, 550405. DISCUSSION.—This species is distinguished by its elongate-oval to pentagonal outline, great depth of the adult, and strong, rather narrow fold. The type specimen of Macandrevia diamantina Dall appears to be a fully grown adult specimen. Its length and width are nearly equal and it has a very narrow pro- file. Its width is greater than most of the specimens of N. abyssa recorded above. In order better to com- pare the specimens of TV. abyssa with Dall's species a specimen (USNM 550402a) of M. diamantina was measured at three stages of its growth as indicated by varices on the shell. At 7 mm of length the width and length were equal; at 12.4 mm of length the width measured 11.5 mm, showing an already length- ening shell. At 16 mm the width was 14.3 mm but the shell had still 3.6 mm more of length to form a strongly elongated adult. Notorygmia diamantina is also much more diamond-shaped than N. abyssa, which has more rounded sides and is rather pentago- nal in outline. The fold and sulcus of .A/, abyssa are far more pronounced than those of Dall's species. Other minor characters help to distinguish these species. The specimens from off Cocos Island are more opaque than N. abyssa and are somewhat yel- lowish in color. They do not show any traces of the dark brown periostracum similar to that appearing on parts of N. abyssa. Macandrevia coatsi Jackson is a name appearing in Helmcke's list of brachiopods in the Zoological Museum of Berlin. The specimens come from the same locality, but not same depth, as listed by Jack- son for M. diamantina. It seems likely that Jackson intended to designate a new species for them but later changed his mind in favor of identification with Dall's species. Jackson's name is a nomen nudum. The validity of the name Notorygmia abyssa, new species, will hold unless or until it can be demon- strated that Waldheimia wyvillei Davidson, described below, can be proved to be sulcate and to belong to Notorygmia. More collecting off Chile will be needed to prove this point. NUMBER 1 1 15 Waldheimia ( = Macandrevia?) wyvillei (Davidson) Waldheimia wyvillii Davidson, 1878, p. 438; 1880, p. 44, pi. iii, figs. 13a, b; 1886, p. 66, pi. X, figs. 5, 6. The name given by Davidson is W. wyvillii but should be spelled wyvillei as explained by Thomson (1927, p. 199). This is a very poorly known species that has been overlooked and its correct genus not established. It was ignored by Thomson. The name is based on a single specimen dredged by the Challenger expedition from locality 229 (lat. 33°31' S, long. 74°33' W) at 2,160 fathoms off Valparaiso, Chile, the same locality that produced Neorhynchia misidentified as Abysso- thyris (Terebratula wyvillei). This specimen proves by its interior details to belong to Macandrevia or Notorygmia. Dr. C. Howard Brunton, Keeper of the Recent Brachiopoda at the British Museum (Natural His- tory), kindly examined this specimen for me, and later, in a hurried visit to the British Museum, I had opportunity to study it. Unfortunately, the specimen is badly damaged. Most of the ventral valve is broken away and the anterior margin has been destroyed. This damage has the advantage of giving a view of the interior where the critical characters reside but it obscures vital exterior characters. Dr. Brunton and I concur in our examination that the ventral valve has dental plates and that the long loop is unsup- ported. These two characters, combined with the open nature of the foramen, clearly indicate the diag- nostic characters of Macandrevia. But the question is: To what species of Macandrevia is Waldheimia wyvillei related, or is it the same or related to Ma- candrevia diamantina Dall, now placed in Notoryg- mia? As figured by Davidson, Waldheimia wyvillei seems to have a rectimarginate anterior commissure, and Davidson (1886, p. 67) stated unequivocally that the dorsal valve is "without sinus." Moreover, Davidson remarked that his species suggests a thin or com- pressed Macandrevia cranium (Miiller). It is possible that Waldheimia wyvillei is a small example of Ma- candrevia americana Dall, which is also known from the coast of Chile (Dall, 1920, p. 357). The fact that Waldheimia wyvillei occurs with Abyssothyris wyvil- lei suggests the possibility that it is a species of Noto- rygmia and another example of the homeomorphy that forms the subject of this paper, but Davidson's unequivocal statement that his species is without a sinus rules out that possibility. According to Dall (1920, p. 357), Macandrevia americana has a wide bathymetric range, from 122 to 2,222 fathoms; con- sequently, the species is not out of place at Challen- ger locality 299. Appendix Pelagodiscus atlanticus King PLATE 4: FIGURES 53-56 For an extended synonymy see Helmcke (1940, p. 230). Although this species has no direct bearing on the problem discussed herein, figures of this interesting and ubiquitous brachiopod are included because it is the commonest deep-sea brachiopod and has been re- ported more widely than any other. It is shown at- tached to a specimen of Neorhynchia profunda (Plate 4: figures 53-56). Also shown is the ventral side, which usually is not seen. The large pedicle and the two sets of setae are clearly visible. LOCALITIES.—S 1067-103; S 1070-22; Mv 70- IH-3,6,8. TYPES.—Hypotypes: USNM 550391e (on Neo- rhynchia) ; USNM 550438. Literature cited Bell, W. C. 1938. Homeomorphy in the Brachiopod Genus Acrotreta. Bulletin of the Geological Society of America, 49:1909-1910. Buckman, S. S. 1901. Homeomorphy among Jurassic Brachiopods. Pro- ceedings of the Cotteswold Naturalists Field Club, 13:231-290. 1906. Brachiopod Homeomorphy: Pygope, Antinomia, Pygites. Quarterly Journal of the Geological So- ciety of London, 62:433—455. Cloud, P. E., Jr. 1941. Homeomorphy, and a Remarkable Illustration. American Journal of Science. 239:899—904. Cooper, G. A. 1930. The Brachiopod Genus Pionodema and Its Homeo- morphs. Journal of Paleontology, 4(4) : 369-382, plates 35-37. 1959. Genera of Tertiary and Recent Rhynchonelloid Brachiopods. Smithsonian Miscellaneous Collec- tions, 139(5): 1-90, 22 plates. 1970. Generic Characters of Brachiopods. Symposium, North American Paleontological Convention, Field Museum Natural History, September 1969, pages 194-263, 5 plates. 16 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Dall, W. H. 1895. Scientific Results of Explorations by the U.S. Fish Commission Steamer Albatross. No. XXXIV.— Report on Mollusca and Brachiopoda Dredged in Deep Water, Chiefly near the Hawaiian Islands, with Illustrations of Hitherto Unfigured Species from Northwest America. Proceedings of the United States National Museum, 17 (1032) : 675- 733 plates 23-32. [Brachiopoda, pages 713-729, plates 30-32.] 1908. Reports on the Mollusca and Brachiopods [Alba- tross Dredging Operations in Western Pacific]. Bulletin of Museum of Comparative Zoology, Har- vard, 43(6) : 205-487, 19 plates. [Brachiopods, pages 205-212]. 1920. Annotated List of the Recent Brachiopoda in the Collection of the United States National Museum, with Descriptions of Thirty-three New Species. Proceedings of the United States National Museum, 57:261-377. Davidson, Th. 1878. Extract from Report to Professor Sir Wyville Thomson, F.R.S., on the Brachiopoda Dredged by H. M. S. Challenger. Proceedings of the Royal Society of London, 27(188) :428-439. 1880. Report on the Brachiopoda Dredged by H. M. S. Challenger during the years 1873—1876. Report on the Scientific Results of the Voyage of H. M. S. Challenger, Zoology, 1:1-67, 4 plates. 1886- A Monograph of Recent Brachiopoda. Transac- 1888. tions of the Linnaean Society of London, series 2, Zoology, 4: 1-248, 30 plates. Emery, K. O. 1960. The Sea off Southern California: A Modern Habi- tat of Petroleum. xii4-366 pages. New York and London: John Wiley and Sons. Helmcke, J. G. 1940. Die Brachiopoden der Deutschen Tiefsee-Expedi- tion. Wissenschaftliche Ergebnisse der deutschen Tiejsee-Expedition auf dem Dampfer Valdivia, 1898-1899, 24(3): 215-316, 43 figures. Hertlein, L. G., and U. S. Grant, IV 1944. The Cenozoic Brachiopoda of Western North America. Publications of the University of Cali- fornia at Los Angeles in Mathematical and Physical Sciences, 3:1-236, 21 plates. Jackson, J. W. 1912. The Brachiopoda of the Scottish National Ant- arctic Expedition (1902 to 1904). Transactions of the Royal Society of Edinburgh, 48(2)19:367-390, plates 1 and 2. Muir-Wood, H. M. 1959. Report on the Brachiopoda of the John Murray Expedition. The John Murray Expedition, 1933-34, Scientific Reports, 10(6) : 283-317, 5 plates. 1960. Homeomorphy in Recent Brachiopoda: Abyssothy- ris and Neorhynchia. [With an appendix by G. F. Elliott.] Annals and Magazine of Natural History, series 13:521-528, plate 7. Thomson, J. A. 1915. The Genera of Recent and Tertiary Rhynchonel- lids. Geological Magazine, new series, 6(2): 387— 392. 1918. Brachiopoda. Australasian Antarctic Expedition, 1911-14, Scientific Reports, Series C, 4(3): 1-75, 4 plates, map. 1927. Brachiopod Morphology and Genera (Recent and Tertiary). New Zealand Board of Science and Art, Manual, 7:1-338, 2 plates. Ulrich, E. O., and G. A. Cooper 1936. New Silurian Brachiopods of the Family Triplesii- dae. Journal of Paleontology, 10(5) :331—347, plates 48-50. Williams, A., et al. 1965. In R. C. Moore, editor, Treatise on Invertebrate Paleontology, Part H, Brachiopoda. 2 vols., 927 pages, 746 figures. New York: Geological Society of America (and University of Kansas Press). PLATES PLATE 1 Neorhynchia strebeli (Dall) Figures 1-11: 1-4, Anterior, dorsal, lateral, and ventral views (X 1) of the holotype (USNM 110741); 5, dorsal view (X 2) of the holotype; 6, 7, posteriorly tilted and dorsal views ( X 4) of the posterior part of the holotype showing the hypothyridid foramen, disjunct deltidial plates and dental plates; 8-10, ventral, posteriorly tilted, and laterally tilted views ( X 4) of the cardinalia of the holotype showing the falcifer crura, slight median ridge, strong socket ridges, and outer hinge plates; 11, interior of the dorsal valve (X 4) of a paratype (USNM 110741a), younger than the holotype, showing cardinalia. Both specimens taken at a depth of 3,801 m in Globigerina ooze, lat. 8°7'30"S, long. 104°10'W, southwest of the Galapagos Islands. Neorhynchia profunda, new species Figures 12-25: 12-15, Anterior, lateral, dorsal, and ventral views (X 1) of a young adult (paratype, USNM 550394b); 16, dorsal view (X 2) of the preceding paratype; 17-19, anterior, lateral, and dorsal views (X 1) of a strongly folded individual (paratype, USNM 550394g); 20-22, anterior, dorsal, and lateral views (X 2) of the preceding paratype showing the growth lines; 23-25, lateral, dorsal, and anterior views (X 2) of another obese, strongly folded individual (paratype, USNM 550394h) showing the small beak and growth lines. All specimens from loc. MV 70—III—6. Figures 26-46: 26-28, Anterior, dorsal, and lateral views (X 2) of a broadly folded, young adult (paratype, USNM 550393n) ; 29-32, dorsal, lateral, anterior, and ventral views (X 1) of a young specimen (paratype, USNM 550393e) ; 33-35, anterior, lateral, and dorsal views (X 3) of an immature specimen (paratype, USNM 550393o) ; 36-39, anterior, ventral, lateral, and dorsal views (X 1) of a broad specimen (paratype, USNM 550393r) ; 40—43, anterior, ventral, dorsal, and lateral views (X 1) of a strongly folded paratype (USNM, 550393s); 44, interior view (X 3) of the posterior part of a dorsal valve of a young specimen (paratype, USNM 550393p) showing cardinalia and adductor scars; 45, 46, interior (X 2) of the dorsal and ventral valves of a young specimen (paratype, USNM 550393q) showing cardinalia with short crura, teeth, and deltidial plates forming a hypo- thyridid foramen. All specimens from loc. S 1070-22. Figure 47: Interior (X 2) of an obese dorsal valve (paratype, USNM 550139o) showing deeply entrenched adductor scars. Loc. Mv 70—III—8. Figures 48-51: 48, Interior (X 2) of dorsal valve of an obese specimen (paratype, USNM 550392e) showing cardinalia with slight development of inner hinge plates and deeply inserted muscle scars; 49-51, dorsal, lateral, and anterior views (X 1) of an elongated obese individual (paratype, USNM 550392i). Both specimens from loc. S 1066-547. NUMBER 1 1 19 PLATE 2 Neorhynchia profunda Cooper, new species Figures 1-5: 1-4, Anterior, lateral, ventral, and dorsal views (X 1) of a large, moderately folded individual (paratype, USNM 550392d) ; 5, dorsal view (X 2) of the same specimen. Loc. S 1066-547. Figures 6-15: 6-9, Dorsal, lateral, anterior, and ventral views (X 1) of an elongated but not strongly folded individual (paratype, USNM 55039li) ; 10-13, anterior, lateral, ventral, and dorsal views (X 1) of another elongated, old adult (paratype, USNM 550391 j) which is not strongly folded; 14, 15, posterior parts (X 2) of ventral and dorsal valves of an elon- gated individual (paratype, USNM 550391m) showing teeth, foramen, and cardinalia with a slight development of inner hinge plates. All specimens from loc. Mv-70-III-8. Figures 16-22: 16, Pebble (X 1) with attached Neorhynchia at left and an Abyssothyris at right (paratype, USNM 550409); 17, dorsal view (X 3) of a complete specimen (para- type, USNM 550433) in alcohol showing the spirolophous lophophore with left side partly unrolled; 18, interior (X 2) of an adult dorsal valve (paratype, USNM 550394t) showing cardinalia and muscle scars; 19, ventral view (X 2) of a specimen (paratype, USNM 550434) in alcohol with part of the ventral valve removed and showing the spiral lophophore from the ventral side; 20, 21, interior ( X 3) of the ventral and dorsal valves of a young adult (paratype, USNM 550393m) showing teeth, hypothyridid foramen, and well-developed, short cardinalia; 22, interior (X 2) of a large adult (paratype, USNM 550435) in alcohol, with part of the dorsal valve removed to show the spirolophe. All specimens from loc. S 1070-22. Notorygmia abyssa Cooper, new species Figures 23—29: 23—27, Dorsal, anterior, ventral, posterior, and lateral views (X 1) of a complete specimen (paratype, USNM 549762); 28, 29, laterally tilted and ventral views (X 2) of the dorsal valve interior of the preceding paratype showing the long, unsup- ported or dalliniform loop. Specimen from Mag Bay Expedition Sta. 27. Notorygmia diamantina (Dall) Figures 30-38: 30-33, Side, anterior, dorsal, and ventral views (X 1) of paralectotype (USNM 122860b) ; 34, dorsal view (X 2) of the preceding specimen showing open delthy- rium; 35-37, anterior, dorsal, and lateral views (X 2) of the lectotype (USNM 122860a) ; 38, interior (X 3) of the dorsal valve of the lectotype showing cardinal process, descending lamellae of the loop, and plates attached to the floor and forming the notothyrial cavity. Both specimens taken at a depth of 2,150 m on mud bottom, lat. 5°56'S, long. 85°10'30"W, southeast of Cocos Island. Abyssothyris elongata Cooper, new species Figure 39: Thin section (X 50) showing the punctae taken just anterior to the umbonal region (paratype, USNM 550436). Loc. S 1070-22. NUMBER 1 1 21 PLATE 3 Notorygmia abyssa Cooper, new species. Figures 1-6: 1-5, Dorsal, anterior, lateral, ventral, and posterior views (X 1) of a para- type (USNM 550402a); 6, dorsal view (X 2) of a large specimen (paratype, USNM 550404) in alcohol showing open delthyrium, shadow of lophophore, and traces of the periostracum. Both specimens from loc. Mv 70—III—6. Figures 7-18: 7—11, Ventral, lateral, posterior, anterior, and dorsal views (X 1) of the holotype (USNM 550402b); 12-14, lateral, anterior, and dorsal views (X 2) of the holotype; 15, 16, laterally tilted and ventral views (X 2) of dorsal valve interior of the holotype showing the dalliniform loop and cardinal process; 17, 18, dorsal views (X 2) of two specimens (paratypes, USNM 550402c-d) in alcohol showing the long plectolophe characteristic of this genus. All specimens from loc. S 1070—22. Figure 19: Ventral view (X 2) of another specimen (paratype, USNM 550405) in alcohol and showing the plectolophe. Loc. S 1066-547. Abyssothyris elongata Cooper, new species. Figures 20-24: 20, Pebble (X 1) with two individuals (paratype, USNM 550401) at- tached, showing living habit; 21-24, ventral, anterior, dorsal, and lateral views (X 2) of a specimen (paratype, USNM 550550) in alcohol and showing the pallial sinuses. Both speci- mens from loc. Mv-70-III-6. Figures 25, 26: 25, Posterior of dorsal valve (X 3) of a fully grown specimen (paratype, USNM 550398x) showing the loop and large cardinal process (note the well-rounded anterolateral extremities of the loop) ; 26, specimen (paratype; USNM 550398n) tilted laterally to show loop in partial profile (X 2). Both specimens from loc. S 1066—547. Figures 27-41: 27, Interior of a dorsal valve (X 2) with part of the ventral valve adhering, showing the loop of a young adult and absence of dental plates; 28, 29, interior (X 2) of two young dorsal valves (paratypes, USNM 550437b,c) displaying the loop; 30-33, an- terior, ventral, lateral, and dorsal views (X 1) of an elongated individual (paratype, USNM 550397q; compare with Neorhynchia, Plate 1: figures 49-51); 34-37, anterior, lateral, ventral, and dorsal views (X 1) of a characteristic specimen (paratype, USNM 550397m; compare with Neorhynchia, Plate 2: figures 6-9); 38—41, lateral, dorsal, ventral, and anterior views (X 2) of the preceding specimen. All specimens from loc. S 1066—547. NUMBER 1 1 23 PLATE 4 Abyssothyris elongata Cooper, new species. Figures 1-14: 1-4, Ventral, lateral, dorsal, and anterior views (X 1) of a paratype (USNM 550400b) showing pallial trunks and a very slightly sulcate anterior commissure; 5-8, ventral, anterior, lateral, and dorsal views (X 1) of an elongate, anteriorly tapering individual (paratype, USNM 550400a); 9-11, lateral, dorsal, and anterior views (X 1) of a wide, swollen, and strongly folded specimen (paratype, USNM 550400c); 12—14, dorsal, anterior, and lateral views (X 2) of the preceding specimen. All specimens from loc. Mv 70-III-8. Figures 15-37: 15-17, Dorsal, anterior, and lateral views (X 1) of an anteriorly tapering but weakly folded specimen (paratype, USNM 550398r) : 18-20, dorsal, anterior, and lateral views (X 1) of a tapering specimen (paratype, USNM 550398q) preserving the main pallial trunks of the dorsal valve; 21-23, lateral, dorsal, and anterior views (X 1) of a wide but anteriorly narrowly folded individual (paratype, USNM 550398v) ; 24-26, anterior, dorsal, and lateral views (X 1) of an oval specimen (paratype, USNM 550398p) wide anteriorly and with a nearly rectimarginate anterior commissure; 27—29, dorsal, anterior, and lateral views (X 1) of a wide specimen (paratype, USNM 550398s) with long pedicle and fairly strongly sulcate anterior commissure; 30-32, anterior, lateral, and dorsal views (X 1) of an elongate specimen (paratype, USNM 550398w) having a short, frayed pedicle; 33-35, dorsal, anterior, and lateral views (X 2) of the preceding specimen; 36, dorsal view (X 2) of a specimen (paratype, USNM 550398i) with broken dorsal valve showing the dorsal side of the loop which has an unusually broad transverse band; 37, lateral view (X 2.5) of a specimen (paratype, USNM 550398y) with pedicle valve removed to show the plectolophus lophophore and the short frayed pedicle. All specimens from loc. S 1066-547. Figures 38—52: 38—41, Lateral, dorsal, ventral, and anterior views (X 1) of a strongly folded specimen (paratype, USNM 550397n) showing traces of the pallial sinuses and a long, frayed pedicle; 42, dorsal view (X 2) of the preceding paratype; 43-46, ventral, lateral, anterior, and dorsal views (X 1) of an oval specimen (paratype, USNM 550397o) having a long pedicle but nearly rectimarginate anterior commissure; 47-49, anterior, lateral, and dorsal views (X 1) of a laterally strongly rounded specimen (paratype, USNM 550397e) with strongly sulcate anterior commissure; 50-52, dorsal, anterior, and lateral views (X 1) of a rectimarginate individual (paratype, USNM 550397h). All specimens from loc. S 1070-22. Pelagodiscus atlanticus (W. King) Figures 53-55: 53, 54, Dorsal and anterior views (X 1) of Neorhynchia with Pelagodiscus (hypotype, USNM 55039le) attached on the sulcate part of the dorsal valve; 55, dorsal view (X 10) of the preceding specimen showing long setae. Loc. Mv 70—III—8. Figure 56: Ventral view (X 10) of another specimen (hypotype, USNM 550438) showing the round, thick pedicle, the short setae of the ventral valve, and a few of the long dorsal setae. Loc. S 1070-22. NUMBER 1 1 25 U.S. GOVERNMENT PRINTING OFFICE: 1972 O 4 64-3l4/l6 Publication in Smithsonian Contributions to Zoology Manuscripts for serial publications are accepted by the Smithsonian Institution Press, sub- ject to substantive review, only through departments of the various Smithsonian museums. Non- Smithsonian authors should address inquiries to the appropriate department. If submission is invited, the following format requirements of the Press will govern the preparation of copy. 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