Studies on the Eartiest

'BY GEORGE GAYLORD SIMPSON

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Y7 -Vu1I4 Article IV.-STUDIES ON THE EARLIEST PRIMATES BY GEORGE GAYLORD SIMPSON FIGURES 1 TO 8 CONTENTS PAGfE ABSTRACT...... 185 INTRODUCTION. 185 I.-A NEW APATEMYID.186 II.-A NEW AMERICAN LOWER ANAPTOMORPID.187 III.-NEW DESIGNATION FOR A EUROPEAN ANAPTOMORPHID.189 IV.-SKELETAL REMAINS REFERRED TO Hemiacodon.190 V.-CLASSIFICATION OF THE ANAPTOMORPHIDA .197 VI.-RELATIONSRIPS OF PALEOCENE AND EOCENE PRIMATES.199 VII.-DISTRIBUTION OF PALEOCENE AND EOCENE PRIMATES.206 VIII-INDEXED BIBLIOGRAPHY OF PALEOCENE AND EOCENE PRIMATES.209 ABSTRACT This paper consists of a series of eight each and discussing them briefly. The brief studies on Paleocene and Eocene fos- sixth study is devoted to the relationships sil primates. The first describes Jepsen- of the five families of Paleocene and Eocene ella, new genus, type J. praepropera, new primates to each other and to the Primates species, from the Middle Paleocene of Mon- in general. Pronydticebus, Caenopithecus tana, referred to the Apatemyidae, of and Anchomomys are referred to the lemuri- which it is the oldest known member. The form family in addition to the second describes Loveina, new genus, type genera commonly placed there. The Plesi- L. zephyri, new species, from the Lower adapidae are held to be definitely lemuroid Eocene of Wyoming, an anaptomorphid and not specially related to Daubentonia. allied to Omomys and Washakius. The The Apatemyidae may not be primates at third proposes and defines the new genus all, but there is at present no other less for Omomys belgicus Teilhard, doubtful place to put them. The Carpo- 1927, from the Lower Eocene of Belgium, lestidae appear to be a peculiarly aberrant pointing out that this is quite distinct from, offshoot of the proto- and probably although allied to, Omomys and that it prototarsioid stock. The usual view that appears to be the most generalized known the Anaptomorphidae are tarsioids is ac- tarsioid. In the fourth study, a partial cepted, but the contents of the family are skeleton referred to Hemiacodon from the somewhat modified and it is pointed out Middle Eocene of Wyoming is described that it is heterogeneous and may now in- and discussed. The skeleton of this sup- clude some non-tarsioid genera. In the posed tarsioid is found to be unique in seventh study knowledge of early primate several respects and to resemble the lemu- distribution is summarized and the occur- roids at least as much as the true tarsioids, rences of each of the 55 genera tentatively and the possible bearings of this unexpected accepted as valid are given in tabular form. fact on primate history are discussed. The The last, eighth, section gives a selected fifth divides the large family Anaptomor- bibliography of the subject and an alpha- phidae into five subfamilies, Omomyinae, betical list of valid genera with references Paromomyinae, , Necro- by which the important literature on each lemurinae and Pseudolorisinae, defining can readily be found. INTRODUCTION In the past fifteen years I have had occa- the course of this work, original specimens sion to study most of the known early of 38 of the 55 recognized genera of Paleo- mammalian faunas and also to identify cene and Eocene primates have been ex- several large new collections of them. In amined, and the literature on all has been 185 186 Bulletin American Museum of Natural History [Vol. LXXVII studied. Incidentally to this, several new accumulated in the form of briefer notes primates were recognized, some important and manuscripts. The purpose of the undescribed specimens of known forms were present publication is to bring out some of studied, a synthesis of the whole complex these accumulated data, which is done in was envisioned and opinions, in some part the form of eight short papers, independent at variance with previous ideas, were except that all relate to the general subject formed as to the affinities and interrelation- of early primates. References to the litera- ships of these obscure . Some of ture cited are gathered together in the these observations and conclusions were in- bibliography (VIII). The accompanying volved in various faunal studies, with illustrations were drawn by John C. Ger- which they were published, but others were mann.

I.-A NEW APATEMYID The Third Scarritt Expedition, under so than in Labidolemur, but probably more so in than on M2 of Jepsenella. There is a very my direction, found 1935 a single speci- minute anteroexternal cusp on the trigonid of Ml, men in the Gidley Quarry in central Mon- relatively smaller than in Labidolemur, and the tana that adds to the ranks of the oldest trigonid as a whole is less sharply square and known primates (if such they are) and that less anteroposterior than in Labidolemur or later genera. The most marked difference, carries the peculiar apatemyid line back however, is the greater elevation of the trigonids into the Middle Paleocene. It tepresents of all three molars in Jepsenella. There is a new genus and species, here described. some suggestion of progressive decrease in tri- The delicate specimen was prepared by gonid height in later forms, Labidolemur to Sin- Mr. Albert Thomson. JEPSENELLA,' NEW GENUS TYPE.-Jepsenella praepropera, new species. DISTRIBUTIoN.-Middle Paleocene, Montana. DIAGNosIs.-An apatemyid with lower trigonids elevated far above talonids, protoconids and metaconids high and subequal, paraconids lower but strong and distinct, that of Ms small- est and median in position, squaring of antero- external trigonid rim less pronounced than in A.M.35292 later forms, hardly noticeable on M3, talonid of M3 short. B Jepsenella praepropera,2 new species TYPE.-Amer. Mus. No. 35292, right lower jaw with M1-3. HORIZON AND LOCALITY.-Gidley Quarry, Upper Lebo, Middle Paleocene, Fort Union 4 Group, Sweetgrass County, Montana. Cs I DIAGNOSIs.-Sole known species of genus. DESCRIPTION On Ml the paraconid ledge is broken, but harmony with M2-3 demands a large paraconid on this tooth and the broken base shows that this cusp was not fully internal, probably less 1 For Dr. G. L. Jepsen, in recognition of his out- standing contributions to knowledge of the Apatemyi- 1. Jepsenella praepropera, new genus dae and in analogy with Teilhardella, Stehlinella and Fig. Sinclairella, names of allied genera. and species. Type, Amer. Mus. No. 35292. 2 Praepropera, impetuous, precipitate, premature Fragment of right ramus with molars. A, outer, in allusion to the extraordinarily advanced specializa- B, crown and C, inner views. Four times natural tion of this very early . size. 19401 Simpson, Studies on the Earliest Primates 187 d.airella, but the difference in this respect be- seen. The posterior mental foramen, beneath tween these two, upper Paleocene to Lower the posterior end of Ml and anterior of M2, is Oligocene, is less than between Jepsenella and almost exactly like that of Labidolemur. Labidolemur, Middle to Upper Paleocene. The length of Mi is unobtainable because of Protoconid and metaconid are about equal breakage and those of M2-3 are only approxi- on M, while on M2 and still more on M3 the mate because the structure prohibits accurate metaconid is somewhat the larger. The talonid placing of caliper points. is very slightly wider than the trigonid on Mi. Depth of jaw on internal side below M2: 4.0. On M2 it is slightly and on M3 decidedly narrower The species is about as large as Teilhardella than the trigonid. The trigonid of Ml is a chardini and intermediate between Labidolemur broad, shallow basin with a continuous, sharp, soricoides and L. kayi in size. It is rather less closed rim on which separate cusps are only than half as large as Sinclairella dakotensis, the indistinctly visible. The hypoconid is the latest and largest known member of the family. highest and most distinct talonid cusp and is suberescentic in form. There is a very vague cuspule on its anterior wing, which abuts against AFFINITIES the base of the trigonid below the notch between Although so sharply different in general protoconid and metaconid. There are vague but distinguishable hypoconulid and entoconid. On aspect from the later genera, there can be the inner side the sharp talonid rim runs into little or no doubt that this form is an apate- the base of the trigonid at its most internal myid, as that term has been revised and re- point, below the metaconid. defined by Jepsen (1934). It has all the On M2 the paraconid is about halfway between an internal (lingual) and a median position, the essential apatemyid characters such as the anteroexternal cuspule is represented by the large incisor root extending beneath M2, faintest rudiment and the squaring of the tri- the peculiarly placed and constructed pos- gonid is barely incipient, the outline being al- terior mental foramen, the (here incipient) most triangular rather than approximately square as in later forms. This squaring seems also quadrate trigonids, the shallow-basined, to be progressive in the later genera, but again sharp-rimmed talonids and the short the difference between Jepsenella and Labidole- talonid on M3 (typical of early apatemyids). mur is somewhat more than would be expected Moreover, its distinctions from later forms from their age difference. The talonid of M2 has the hypoconid crescent shorter and more are on the whole and in varying intensity angular than on Mi. in line with the evolutionary trends shown On M3 the paraconid is smaller than on M2 by the later genera. It will not be sup- and is strictly median. The trigonid is tri- posed that the few species of these rare angular, and only the angulation of the proto- conid-paraconid crest suggests incipient de- animals so fortuitously discovered repre- velopment of the more typical apatemyid quad- sent an exact phylogeny-four of the six rate outline. Except for being smaller and es- American genera are monotypic and seven pecially narrower, the talonid of M3 is essentially of the nine American species are known es- similar to that of M2. It becomes elongated in later apatemyids, but here there seems to be sentially from only one specimen each. little difference between Jep8enella and Labidole- Yet with some fluctuation these known mur. forms do represent a single structural se- MEASURE]IMENTS quence, the long, almost continuous record Ml M2 M3 of which is very remarkable in view of the Width Length Width Length Width extreme rarity of known individual speci- 1.2 1.6 1.4 1.5 1.1 mens, numbering only a dozen or fifteen in all and yet representing at least six and As in all apatemyids, the lower jaw is very deep and stout in proportion to the molars. The possibly seven distinct ages, from Middle incisor root is gone, but part of its great alveolus, Paleocene (Upper Lebo) to Lower Oligo- extending far back beneath the molars, can be cene (Chadron).

1I.-A NEW AMERICAN LOWER EOCENE ANAPTOMORPHID In a small collection of early Tertiary allied to Omomys. Mr. Love generously fossils made by Mr. J. D. Love in western presented this specimen to The American central Wyoming and referred to us for Museum of Natural History in order that identification, Dr. Walter Granger and I it might be more carefully compared with recognized an interesting primate evidently and included in the largest collecton of 188 Bulletin American Museum of Natural History [Vol. LXXVII early primates. Detailed comparisons have now been made and the specimen proves to represent a new genus, which is described in this paper. TAXONOMY LOVEINA,1 NEW GENUS TYPE.-Loveina zephyri, new species. A.M. 32517 DISTRIBUTION.-Lost Cabin Formation, Wyoming, possibly also Gray Bull and Lysite, 'B Wyoming, and Almagre, New Mexico. Lower Eocene of . DIAGNOSIs.-An anaptomorphid with dental formula _ . Jaw relatively short, sym- 2.1.3.3 4 physis deep, dental series closely crowded. Two lower incisors small and subequal, much smaller than canine, nearly erect. Lower canine not reduced, alveolus about as large as that for P2. PI absent, P2 with one large vertical root. P3 slightly smaller than P4 and secondary cusps less distinct, otherwise almost identical. P4 rela- tively transverse, compressed and rounded tri- angular in plan, slightly higher than Ml, with distinct paraconid and metaconid. Ml almost as in Omomys, but paraconid more internal, nearer to but still quite distinct from metaconid, Fig. 2. Loveina zephyri, new genus and marginal enamel nearly smooth but enamel species. Type, Amer. Mus. No. 32517. Frag- wrinkled in talonid basin. ment of left ramus with P3-MI. A, inner, B, crown and C, outer views. Four times natural size. Loveina zephyri,2 new species TYPE-.Amer. Mus. No. 32517, left lower jaw remarkably erect in comparison with those of with P3-M2, all anterior alveoli, and root of M2. presumably allied genera. The canine alveolus Collected by Mr. J. D. Love. is about as procumbent as that for the more HORIZON AND LoCALITY.-Near head of Bad- posterior incisor, and the alveolus for P2 is almost lands Gulch at the south end of Table Mountain, vertical. Kirwin Quadrangle, 6 miles east of Dubois, Fre- P4, the most characteristic single tooth, is mont County, Wyoming.3 In the Wind River almost as broad as long and has a compressed, Group, associated with a small but distinctive rounded-triangular outline quite distinct from fauna almost surely of Lost Cabin age. that of the homologous tooth in typical Omomys. DIAGNOSIs.-Very slightly smaller than ?Love- There is a well-differentiated metaconid and a ina vespertina, horizontal ramus less deep, paraconid fully differentiated and only slightly Mi with paraconid more internal, coronal enamel smaller than the metaconid. The talonid is more distinctly furrowed, external cingulum much as in Omomys, but is relatively smaller and weaker. extends less toward the external side. P3 is closely similar to P4 but smaller and with para- DESCRIPTION conid and metaconid less distinct, although both are visible. These features make it still less The incisive alveoli are imperfectly preserved, like such allied genera as Omomys than is P4. but it is hardly possible that there were more M1 is of the familiar anaptomorphid type than two incisors, which had small and subequal and very close to that of Omomys except for the roots, that of the first perhaps slightly the larger. small (but possibly important) details men- Both are procumbent, the second less so, but tioned' in the diagnoses: paraconid slightly only in slight degree, the roots being, in fact, nearer the metaconid, coronal enamel furrowed, external cingulum barely indicated. 1 Mr. J. D. Love, who collected the type. 2Zephyri, of the west wind, in allusion to the western locality, in analogy to the trivial name of its MEASUREMENTS probable ally ?L. vespertina, and in suggestion of its occurrence in the Wind River Series. P3 P4 Ml ' The locality is designated "XX" in Love's field Length notes and will be exactly shown by him in forth- Width Length Width Length Width coming studies. 1.6 1.4 1.8 1.7 2.2 1.8 1940]10Simpson, Studies on the Earliest Primates 189

AFFINITIES resembles more than it does Hemiacodon, Among previously named genera, the for instance, but rather less than it does closest resemblance to this form is shown Washakius. by Omomys, Hemiacodon, Washakius, Sho- The question arises whether the Lower shonius and Navajovius, all from the Ameri- Eocene species previously tentatively re- can Lower or Middle Eocene. The ante- ferred to Omomys (a Middle Eocene genus) molar dentition of Navajoviu-s is so different do not belong rather to Loveina. These that special relationship seems to be ex- species are ?Omomys vespertinus Matthew, cluded. Hemiacodon has the anterior in- 1915, and ?Omomys minutus (Loomis, 1906). cisor relatively much larger, P2 more re- In neither of these are antemolar teeth duced, P3_4 without distinct paraconids known and without these the generic as- and with larger heels. The molar enamel sigDment is highly uncertain. It is un- is also more rugose, and in general the struc- likely that either really belongs' in Omomys. ture is not very close to Loveina. Washa- ?Omomys minutus' is surely a different spe- kius shows a much closer agreement in the cies from the other two in question. Its relative sizes and structure of the antemo- more elongate alveoli for P3-4 suggest that lar teeth but P3-4 are less aberrant or ad- these teeth were unlike those of Loveina vanced (although Washakius is the later zephyri and make common generic assign- of the two genera). M1 has a prominent ment uncertain. Loomis' species is still metastylid that is much less strong or incertae sedis and may be left questionably wholly absent in Loveina, and the enamel in ?Omomys pending discovery of better appears to be more wrinkled. The small material. subequal and nearly vertical incisors, the relatively unreduced canine and P2, the Only Ml can be compared in ?Omomys crowding of the dental series, the outlines vespertinus and Loveina zephyri. On this of the premolars, and some lesser features slender basis the species might be synony- make for a special resemblance between mous, although they probably are not, or Washakius and Loveina and suggest that they might belong in different genera. they are very closely related. Loveina Only discovery of the lower antemolar might be supposed ancestral to the later dentition of ?O. vespertinus could settle form except for the probably slightly more this problem. In defining L. zephyri as dis- aberrant P3-4. In Shoshonius, only M1 tinct, I am influenced not only by the prob- can be compared and this is very like M1 of ability that this is correct but also, as I Washakius. It is impossible to say whether think proper, by the fact that L. zephyri a closer or more distant relationship to is surely definable generically and repre- Loveina is indicated. sents a new genus to which ?O. vespertinus, Omomys, the best known genus of this the type of which is not generically identi- group and in a sense its type, has the in- fiable, may or may not belong. To define cisors more differentiated and more pro- this new genus on a specimen dubiously re- cumbent than in Loveina, P2 more reduced, ferred to ?O. vespertinus would inevitably the premolars less crowded and more elon- lead to serious confusion. There is, how- gate, paraconids barely rudimentary on ever, at least as much chance that vesper- P3-4, and other lesser distinctions in part tinus belongs to Loveina as to Omomys and already mentioned. Loveina is clearly re- it might tentatively be called ?Loveina lated in some degree to Omomys, which it vespertina.

III.-NEW DESIGNATION FOR A EUROPEAN ANAPTOMORPHID In 1927 Father Teilhard de Chardin de- He recognized that this would probably scribed a primate from the Lower Eocene prove to be generically distinct, but he referring it tentatively to the I Placed by Loomis in and transferred of Belgium, by Matthew (1915) to Omomys, to which it is clearly American Middle Eocene genus _)moinys. more nearly related. 190 Bulletin American Museum of Natural History [Vol. LXXVII has not had occasion to make the compari- Omomys. He foresaw that generic separa- sons involved in checking this point. Upon tion was probable, but did not take this making these comparisons for myself some step, largely because not certain that the years ago I observed that the European Belgian species did have three incisors. form is certainly generically distinct and After review of the various allied American extremely important. This occasion is genera and the discovery that some of the therefore taken to give the genus a name, American Lower Eocene "Omomys" do not and the circumstances fortunately and belong in that genus and that probably appropriately permit that it be named for none of them do, it is clear that the Belgian its discoverer. species is also a representative of a distinct genus. TEILHARDINA,1 NEW GENUS Teilhardina is of extraordinary interest TYPE.-Omomys belgicus Teilhard, 1927. not only as the oldest European anapto- DISTRIBUTION.-Lower Eocene of Belgium. morphid but also because it is, in the known DIAGNOSIs.-Dental formula . At parts, the most nearly generalized and the ? 3.1.3-4.3 least two and possibly three small lower inci- most primitive of all known tarsioids, or sors, moderately procumbent. Canine root even of all known primates (if the tupaioids larger than incisors or P2. Vestigial P1 some- be excluded from the Order, contrary to times present. P2 definitely smaller than my present opinion). Despite its close re- canine but not much reduced. P3_4 of elongate oval outline, not transverse or compressed, with semblance to Omomys, it differs from that low, rudimentary paraconid. Distinct meta- likewise primitive genus in numerous slight conid on P4, none on P3. P4 talonid simpler particulars throughout the dentition, and than in Omomys, trenchant, with small basin every difference seems to stamp Teilhardina strictly on internal side of tooth. Lower molars with paraconids distinct, not completely internal as less distant from truly prototypal pri- but more so than in Omomys, proper. M3 with mate morphology. slender, sharply differentiated, simple third lobe. Teilhardina is distinctly more 'like No metastylids. Enamel nearly smooth. Omomys than like Loveina. It could be Tooth series continuous but not crowded. structurally ancestral to Loveina, but has As Teilhard (1927, pp. 16-18) pointed no special indication of the peculiarities of out, the closest known ally of this form is the latter. IV.-SKELETAL REMAINS REFERRED TO HEMIACODON Matthew (1915, p. 451) has mentioned Neither of these genera could possibly in- but did not describe, a partial skeleton clude the other skeletal elements found which he believed to belong to Hemiacodon. with them. There is also an isolated ophid- Skeletal elements of early primates are ex- ian vertebra. ceedingly rare and this specimen is of out- standing interest. GENERIC REFERENCE The specimen is Amer. Mus. No. 12613, Wortman (1903, p. 359 [209 of the sepa- found by Dr. Walter Granger in 1905 in rate]) figured a calcaneum like that in- the Upper Bridger, C5, on Henry's Fork, cluded in the present lot and referred it Bridger Basin, Wyoming. It includes a questionably to Microsyops. The basis considerable part of the hind limbs of one for the reference was that the calcaneum is individual, as detailed below, two or more evidently of a primate, that Wortman be- elements of another individual of the same lieved Microsyops to be a primate, and that species, and some fragments found at the he considered no other Bridger primate to same spot but certainly not part of the same be of appropriate size for association with individual or of the same genus. the calcaneum. Matthew (1915, loc. cit.) These extraneous fragments include M3 maintained that this sort of calcaneum and and a symphysial fragment of Hyopsodus the other elements associated with it in the and M2 and a calcaneum of Notharctus. present specimen probably belong to Hemi- acodon, the evidence being as follows. 1 Father P. Teilhard de Chardin. 1.-Calcanea of similar kind and size are 19401 Simpson, Studies on the Earliest Primates 191 confined to the Upper Bridger, and Hemi- VERTEBRAE acodon is likewise confined to that level. There are parts of eight vertebrae pos- 2.-Bones of similar type occur more sibly of this individual, but all are poorly rarely in the Lower Bridger, these are sig- preserved and there may be some admix- nificantly smaller, and Omomys, a smaller ture (as suggested by the fact that an ophid- genus related to Hemiacodon, occurs at that ian vertebra is included in the same lot). level. Two are posterior dorsals, perhaps the last 3.-On the other hand, Microsyops is more abundant in the Lower than in the two, four probably lumbars (although at Upper Bridger and the species only least one may be an anterior caudal), one a slightly smaller. medial or distal caudal, and one a centrum 4.-Cynodontomys, a close ally of Mi- of doubtful position. The best preserved crosyops, is fairly common in the Wind dorsal has the prezygapophyses, neural River and Bighorn Basins, but no skeletal spine and anapophyses broken off, but material of the sort under discussion has otherwise agrees closely with the last dor- been found there. sal of Tarsius except for being relatively In short, 1-4 show that the distribution deeper, absolutely larger, and with corre- of this type of skeletal material coincides sponding greater production of the proc-

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Fig. 3. Hemiacodon. Amer. Mus. No. 12613. Side views of three vertebrae; A, dorsal, B, proximal caudal and C, median caudal. Three times natural size. with that of Hemiacodon and its allies, and esses. As Tarsius hardly differs signifi- not with that of Microsyops and its. cantly from or various other primi- 5.-The size is more appropriate for tive primates in this bone, the evidence is Hemiacodon than for Microsyops. not strong. The four lumbars or anterior 6.-Skeletal elements of very different caudals are so poorly preserved that they type and of more appropriate size for show nothing of interest, except that they Microsyops are occasionally found in are very sharply keeled ventrally, more so dubious association with that genus. than in any genus with which I have made 7.-The occurrence together of bones of comparison although Tarsius, Lemur, Ga- this general type and teeth of the Omomys- lago and some others have some of the lum- Hemiacodon group is repeated in the Lower bars slightly keeled. This keel makes it Eocene of Belgium, where members of the improbable that these elements are caudals. Microsyops group have never been found. The median caudal, of which only one end is 8.-It is not demonstrated, and is rather preserved, is of the type common to all improbable, that Microsyops is a primate, primitive, long-tailed primates. The verte- whereas Hemiacodon and the animal to brae as a whole cast no real light on affini- which these bones belong certainly are. ties, but seem worthy of record. This does not amount to rigid proof, but it is adequate evidence to proceed on the PELVIS theory that these skeletal parts do belong Most of the left ilium and ischium and to Hemiacodon. part of the pubis are preserved. The pel- 192 Bulletin American Museum ofNatural History [Vol. LXXVII vis as a whole is strikingly and unexpect- distinguish it equally from Hemiacodon, edly lemuroid in aspect. From Lemur it and Tarsius shares with Hemiacodon no differs principally as follows: other non-lemuroid characters. Aside from 1.-The (anteroinferior) iliac spine is characters also seen in living , there equally prominent but considerably shorter, is no special resemblance between Hemiaco- a tubercle rather than a crest, and is more don and Notharctus in the pelvis, and con- lateral than ventral. In both respects it siderably less between Hemiacodon and resembles Galago, but is somewhat more . prominent than in that genus. 2.-The posterior lip of the acetabulum FEMUR is slightly less produced. Proximal and distal ends of both femora 3.-The ischial spine is posterior to the are preserved, but slightly crushed and acetabulum, rather than above its pos- broken. The length cannot be deter- terior rim, and is slightly smaller, although mined. The bone is larger than in Tarsius sharp. spectrum throughout, but the shaft is only

A.M. 12613

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Fig. 4. Hemiacodon. Amer. Mus. No. 12613. Outer view of left side of pelvis. Three times natural size.

4.-The lateral surface of the dorsal bar slightly heavier relative to the size of the of the ischium is more sharply crested. ends. The femur closely resembles both 5.-The free part of this bar is slightly Tarsius and Lemur, which are rather simi- shorter (cf. Galago), the dorsal end of the lar in this respect. Special resemblances descending process distinctly wider antero- and distinctions are as follows: posteriorly. 1.-The neck is less definite and con- The last point, which seems rather super- stricted than in Lemur, the notch between ficial in any case, is the only one in which head and greater trochanter shallower, any special resemblance to Tarsius is seen. with the articular surface extending onto In Tarsius the iliac tubercle is practically it, and the fovea is well marked. These absent, but what may be its vestige oc- are all resemblances to Tarsius, but also in cupies nearly the position of the strong equal or greater degree to Galago. process in Hemiacodon. Otherwise the very 2.-The shape and size of the lesser tro- distinctive characters differentiating the chanter are as in Tarsius, differing very pelvis of Tarsius from that of the lemurs slightly from Lemur, but the process is di- 1~~~~~~~~~~~~~~~C

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"0 194 Bulletin American Museum of Natural History [Vol. LXXVII rected more posteriorly than in either re- cent genus. Here, again, resemblance to Galago is rather close. 3.-The third trochanter is slightly more proximal than in Tarsius or Lemur, and is A.M. 12613 markedly weaker than in Tarsius, more like Lemur in this respect, and very like Galago in both features. 4.-A fairly prominent ridge runs onto the shaft from the greater trochanter, much 3 as in Tarsius, and unlike Lemur. Galago 1 is intermediate. 5.-Both distal ends are somewhat crushed laterally, but allowing for this they appear to be almost identical in form with this part in Lemur or Tarsius, which seem to have no significant difference here except that the condyles project further poste- riorly in Lemur and in the present specimen. TIBIA Proximal ends of both tibiae are pre- served, but no recognizable fragment of the fibula. It is thus impossible to determine whether Hemiacodon shared with Tarsius the nearly unique fusion of tibia and fibula.I The fibula was free proximally, but so is it in Tarsius. The parts preserved are not very distinctive from either Tarsius or Lemur, although the articular surface Fig. 6. Hemiacodon. Amer. Mus. No. seems to have been more nearly transverse 12613. Calcaneum, cuboid, navicular, entocu- in neiform and first metatarsal of the right hind foot. to the shaft than either. Three times natural size. PES seems to affect all parts of the bones evenly The right calcaneum, cuboid, navicular, except that the elongation of the calcaneum entocuneiform and first metatarsal are pre- is almost entirely distal, the tuberosity be- served. There are also a second right cal- ing relatively less elongate. Aside from caneum and first metatarsal of the same proportions, the structure and articula- species which of course are not of the same tions of these elements are almost exactly individual.2 The simplest description of as in Lemur, the only noteworthy difference these bones is that they are in every respect being the presence of a marked tubercle on close to Lemur except that all (except the the posterior surface of the entocuneiform metatarsal) are more elongate and slender. which I do not find so strongly developed All are elongate about equally, in propor- in any of the other forms compared. tion to Lemur. The cuboid, navicular and This elongation of the tarsus is, of course, entocuneiform are of roughly equal size in a gross resemblance to Tarsius (and also to Lemur and this relationship is preserved in Galago and some other lemuroids), but Hemiacodon although all are so much more Hemiacodon is by no means midway be- slender. This difference in proportions tween a primitive lemuroid condition and 1 This was already typically developed in the Euro- a fully tarsioid stage: it is very much pean Middle to Upper Eocene Necrolemur and Pseudo- . nearer the former. It is still fully lemu- 2 They may possibly have been placed with the roid, with none of the really distinctive specimen for comparison with it, and not have been found with the rest of the material. features (chiefly in slender bones and their 1940] Simpson, Studies on the Earliest Primates 195 shafts) seen in the tarsus of Tarsius. Fur- thermore the elongation is not proceeding A.M. 12613A as in Tarsius or Galago. In the latter, but in greater degree in Tarsius, the navicular is enormously elongated relative to the primitive lemuroid condition and the cu- \ A B boid very little elongated, while the ento- cunleiform is the smallest bone of the three Fig. 7. Hemiacodon. Amer. Mus. No. and seems actually to have shortened 12613A. Right astragalus, A, dorsal view; slightly relative to the primitive condition. B, plantar view. Three times natural size. In Hemiacodon all have elongated equally and are of approximately equal size. The first metatarsal differs from that of Tarsius, for the ectal facet is more concave, Lemur in the relatively much greater de- ectal and sustentacular facets sharply velopment of the tubercle for the peroneus separated by a groove and the pit deeper longus, and in the almost complete sup- and stronger-all resemblances to Lemur. pression of the more internal of the two The astragalus as a whole is strikingly like grooves on the phalangeal articulation so that of Galago. that the median and internal ridges tend to form a single, large, cylindrical facet, a COMPARISONS AND AFFINITIES modification approached by Tarsius and The supposed Paleocene and Eocene by Galago. tarsioids are known chiefly from teeth and Among the other fragments present are jaws, with good skulls of Tetonius and the distal end of another metatarsal, and Necrolemur, poor and partial skulls of two several fragmentary (but no complete) or three other genera, and various other phalanges. The distal end of a metatarsal fragments. Comparison of limb material is symmetrical, closely similar to the third can be made only with Teilhardina, to or fourth metatarsal of Lemur. Some, which (as Omomys) Teilhard (1927) re- perhaps all, of the phalanges were distinctly ferred a calcaneum and astragalus, with arched, not straight as in Tarsius. The Necrolemur, to which Schlosser (1907) re- distal articulations preserved are all of the ferred a femur, tibia-fibula and calcaneum, simple grooved or pulley type, some shal- with Pseudoloris, of which Weigelt (1933) low and some deeper. An articulation for described a fairly complete hind limb, and a terminal phalanx is largely plantar. with Microtarsioides, of which there is a poorly preserved partial skeleton (Weigelt, OTHER SPECIMENS 1933). Comparable parts are also known There are about ten other calcanea of this in several genera, such as Notharctus (Greg- general type in our Bridger collection, with ory, 1910) and Plesiadapis (see Simpson, some variation in size but little in form. 1935), that are definitely lemuroid and not There are several fragmentary astragali closely related to Hemiacodon if the dental perhaps referable to Hemiacodon, of which evidence is at all trustworthy. I figure the most complete. Its lemuroid The calcaneum of Teilhardina is similar aspect, size and (as far as the facets are to that of Hemiacodon, but its distal end is preserved) articulation with the calcanea relatively less elongate, as might be ex- suggest this reference which is nevertheless pected in an earlier form. The astragalus far from certain. This differs from Lemur figured by Teilhard is, however, quite un- chiefly in the slightly deeper head, more like that very tentatively referred to Hemi- vertical fibular facet and less pronounced acodon, so much so that it is improbable that flexor hallucis groove. The depth is more both the references are correct. The cal- lemuroid, but the other two features are canea confirm to a limited extent the den- minor or slight resemblances to Tarsius. tal evidence that Hemiacodon and Teilhar- The probably more important characters of dina belong to a general Omomys-like the inferior face oppose comparison with group. 196 Bulletin American Museum of Natural History [Vol. IxxtvII

The femur referred to Necrolemur by The known limb bones of Hemiacodon Schlosser resembles that of Hemiacodon in appear not to have any characters typical the position of the third trochanter, which of Notharctus, Adapis or Plesiadapis, but is, however, still more proximal and some- only to share with them some characters what larger in the European form.' The that mark the lemuroids in general. imperfect preservation of the tibiae re- Comparison with recent genera, as indi- ferred to the two genera permits no useful cated in the preceding description, shows comparison, at least without being able to that Hemiacodon is certainly a primate and compare the originals. The tuberosity of that it resembles both lemuroids and tar- the calcaneum referred to Necrolemur is sioids. There appear to be no definitely very like that referred to Hemiacodon, but tarsioid characters that are not either too the distal end is considerably more elon- superficial to be granted any importance or gate, slender, simplified and circular in sec- equally or more clearly shown in the long- tion, specializations in the direction of Tar- footed lemuroids typified by Galago. The sius, to be expected in a later tarsioid genus. tarsal elongation, which might be taken as The limb of Necrolemur could be derived a tarsioid character, is less than in the lemu- from one like that of Hemiacodon, but the roid Galago and is somewhat different in points of comparison are so few and there kind from either tarsioids or lemuroids are so many elements of doubt in the whole among recent forms. On the whole the subject that this conclusion carries little tarsus, and indeed all the preserved parts force. of the skeleton, are more like the lemuroids As far as can be judged from Weigelt's than like Tarsius. brief description and diagrammatic figures, If these bones were judged entirely on Pseudoloris shows considerable resemblance their own merits, without reference to allied to Hemiacodon in the hind limb. The genera or to the teeth of Hemiacodon, prob- iliac spine seems to be much as in Hemiaco- ably no one would refer them definitely to don, but the anterior end of the ilium is the Tarsioidea. They might be assigned less expanded (possibly broken?) and no with greater or less probability to the ischial spine appears in Weigelt's drawing, Lemuroidea or they might be considered as which includes the region where this oc- indicative of an offshoot allied to both curs in Hemiacodon. On the femur, the groups. The jaws and dentition of Pseudo- head, greater trochanter and lesser tro- loris give almost indisputable evidence of chanter seem to be almost as in Hemiaco- alliance with Tarsius. The skulls of Ne- don, but Weigelt does not mention or illus- crolemur and Tetonius suggest the same trate a third trochanter. If this is absent, affinity in somewhat less degree. Genera it is an unexpected difference from known like Omomys and Hemiacodon have many allied forms. The distal end of the femur dental peculiarities in common with these allows of no useful comparison, nor does probable tarsioids and are linked to them the tibia. The preservation and publica- by various more or less annectent types, tion of the calcaneum and astragalus sug- yet generally similar dentitions did occur gest a general similarity in aspect, without among definite lemuroids, as witness Pro- supplying special details bearing on affinity. nycticebus. The skeleton of Hemiacodon, Microtarsioides is so poorly preserved, as far as known, is at least as lemuroid as despite the discovery of a partial skeleton, tarsioid, probably more. Comparable parts that almost no helpful comparison is pos- in the almost definitely tarsioid Necrolemur sible. Weigelt thinks that the calcaneum and Pseudoloris are not at all conclusive but probably was not elongated, a remarkable could stand between Hemiacodon and Tar- difference from any known tarsioid, even sius in adaptive type and phyletic indi- in the Eocene. It is not certain that Mi- cations, probably being nearer the former. crotarsioides really belongs in this group. This is a very complex series of resem- blances and differences, and not enough 1 The backward extention of the distal condyles, facts are known to settle the problems emphasized by Schlosser, does not seem to me to be greater than in most lemuroids. raised. The evidence of Hemiacodon, in 1940] Simpson, Studies on the Earliest Primates 197 conjunction with that of its probable and the' tarsioids in some respects. In this possible allies, suggests the possibility that latter case, it would probably be quite im- the tarsioids and lemuroids were not as possible to determine the affinities of an sharply distinguished in the Eocene as has early primate unless it were much better commonly been supposed, that there were known than any is at present. then many divergent lines from a basically The comparative anatomy of the recent lemuroid, tupaioid-like stock, some more forms is also equivocal. Competent and and some less Tarsius-like, and that Tarsius thorough students differ so widely that, for is the sole survivor of one of these lines example, one says that "Tarsius is a Lemur nearly represented in the Eocene by Pseu- of the Lemurs" (Woollard, 1925, p. 1182) doloris and more distinctly by Necrolemur, and another that "A generalized common etc. In this case it would perhaps be more type which might have given rise to both accurate to think of Tarsius as an aberrant the Tarsioidea and the Lemuroidea .... and peculiarly specialized lemuroid than could hardly be distinguished from a gen- to think of it as representing a separate eralized eutherian " (Le Gros major division of the Clark, 1934, p. 271). On the first vievw' primates, independ- one could expect, a priori, that the early ent since an indefinitely remote time. fossil forms would be lemuroid in a general The evidence does not conclusively support sense probably with a tendency to develop this as a theory, but it does suggest it as a tarsioid-like characters irregularly in vari- good working hypothesis. It is still pos- ous lines. In the second view, the a priori sible, but seems to me improbable, either presumption would be that the lemuroids (1) that Hemiacodon and its allies are true and tarsioids were already quite distinct in and fully differentiated tarsioids resembling the Eocene. It is generally stated that the the lemuroids only by convergence or in latter is the case, but the actual fossil evi- pre- or proto-primate characters, or (2) dence, dubious as it is, now appears rather that they are lemuroids convergent toward to favor the first alternative. V.-CLASSIFICATION OF THE ANAPTOMORPHIDAE Several relatively small and more or less prove real affinity, but they are the only clearly defined groups of Paleocene and logical basis for a working arrangement Eocene primates have been defined as such as is desirable. There is, in my opin- families: Adapidae, Plesiadapidae, Apate- ion, insufficient reason for family separa- myidae, Carpolestidae. There remain tions, and the groups of genera thus de- some twenty-eight genera most of which fined may perhaps be best placed at present are usually referred to the Anaptomorphi- as provisional subfamilies of Anaptomor- dae or to the Tarsiidae sensu latissimo. phidae. Considering their wide geographic Aside from a few very doubtful genera, range and enormous span of time covered, like Phenacolemur, Trogolemur and Uintaso- the scarcity rather than the abundance of rex, the diversity of these does not exceed definable genera is surprising and it may that of many single mammalian families be predicted that many more will be dis- and from this point of view there is no covered. Tentative definitions of the pro- strong reason for rejecting their collocation. posed subfamilies follow: On the other hand, the reasons for so unit- OMOMYINAE.-The more generalized ing them are in large part negative. They forms. At least two incisors always pres- are enough alike in the known parts, to be ent as far as known. Canines unreduced. related but there is in most cases little or P4 about as high as M1 and incipiently mo- no positive assurance that the affinity is lariform, with metaconid and sometimes real and special. paraconid, but heel short. Molar para- On the basis of the.known dentitions, conids distinct, not fusing with metaconids, these genera may be grouped by a balance generally submedian on M2_3. Heel of M3 of dental resemblances. This evidence is simple (except in Washakius). P3-4, where imperfect and the resemblances do not known, not elevated and with strong proto- 198 Bulletin American Museum of Natural History [Vol. LXXVII cones. Upper molars simple, trigonal, with Abel's "Tetoniidae"2 (1931), except that small hypocones. Included genera: he includes in it the surely extraneous car- Omomys, Teilhardina, Loveina, Dyseolemur, polestids. It is nominally Wortman's Washakius, Shoshonius, Hemiacodon, Nava- Anaptomorphinae, but the concept is jovius, Chumashius. Palenochtha is near radically different. The differences in the this group in morphology, but it seems to anterior teeth are puzzling, but the genera be diverging slightly toward Paromomys seem to be closely related. No very similar and so is placed with the latter. Pseudo- forms are known from Europe. loris is also possibly allied to this group but NECROLEMURINAE.-One enlarged an- is sufficiently distinct to warrant placing in terior lower tooth. P4 not elevated, be- a separate subfamily in the absence of an- coming nearly molariform but with a short nectent types. This subfamily is Wort- heel. Paraconids of M2-3 fusing with meta- man's Omomyinae with little change. conids, trigonids basined and subovate. PAROMOMYINAE.-TwO large anterior M3 formed by three nearly equal lobes. lower teeth, perhaps an incisor and the P3-4 low, oval in contour. Upper molars canine, the first with root extending be- quadrate, large hypocones developed on neath the second, and teeth between these the border of a posterointernal basin, meta- vestigial or absent. P4 about as in Omomy- conule duplicated and in the more advanced inae or less molariform. Molar paraconids forms numerous accessory cuspules present. distinct or nearly fused with metaconids, Genera: Necrolemur, Microchoerus. Nan- internal in position. Trigonids subquad- nopithex may belong here, but this peculiar rate, short. Talonid of M3 elongated and and very imperfectly known animal is of with double hypoconulid (except Palenoch- uncertain affinities. Most students agree tha). P3 anteroposterior. P4 transverse, in making this a family, under the name not elevated, with strong protocone. Necrolemuridae or Microchoeridae, and Upper molars without cuspidate hypocones there is no particular objection to this ex- but with a posterointernal cingulum basin cept that it seems unnecessary. While (rudimentary in Palenochtha). Genera: Microchoerus is unusual in the prolifera- Paromomys, Palaechthon, Plesiolestes, Pal- tion of secondary cuspules, this is a super- enochtha. Trogolemur or the Necrolemu- ficial specialization, not of family rank in rinae might be derived from this subfamily itself in comparison with other mammalian and if so could perhaps be included in it, families, and one that can be followed by but at present this is largely hypotheti- almost complete transitions and in a short cal. span from the quite simple Necrolemur ANAPTOMORPHINAE.-Anterior teeth zitteli to the complex Microchoerus ornatus. highly variable within the group. P4 not Exact relationships to various other anap- molariform but much enlarged and rising tomorphids (or to the anaptomorphids) to a single high apex, metaconid rudimen- are so dubious and their possible indications tary or absent. Molar paraconids tending so complex that the elevation of these two to fuse with metaconids. M3 more or less genera to family rank at present would reduced, heel simple. P3-4 enlarged, each seem merely to complicate and unbalance with a single high external cusp and a much taxonomy unnecessarily. As noted, there lower protocone. Upper molars trigonal, is a distinct possibility that the necrolemu- with minute cingulum hypocones. Upper rines are especially related to the paromo- and lower molar cusps less marginal than myines, but only a possibility in the ab- in other subfamilies. Genera: Anapto- sence of any annectent Upper Paleocene morphus, Euryacodon,l Uintanius, Absaro- and Lower Eocene types. kius, Tetonius. This group is "V" of Mat- PSEUDOLORISINAE.-Dentition closely thew's key (1915, p. 448), plus Uintanius, similar to that of Tarsius throughout. which seems to me to belong here, and it is Genus: Pseudoloris. So far as the dental 2 Since he includes Anaptomorphus and since his family is simply a restricted conception of the long- Euryacodon is probably synonymous with Anapto- established Anaptomorphidae, there is no reason for morphus, but this is uncertain. the change of name. 19401 Simpson, Studies on the Earliest Primates 199 evidence goes, this genus stands consider- Hoanghonius, from a horizon in China ably closer to Tarsius than does any other now considered Oligocene by the Chinese known from the Paleocene or Eocene, and Survey, is perhaps a tarsioid, but is too un- should perhaps be placed definitely in the certain for reference to the Anaptomor- Tarsiidae. Its inclusion in the Anapto- phidae or any other definitely established morphidae, very provisional and frankly family. The European Anchomomys, Pro- conventional in any case, is justifiable only nycticebus and Caenopithecus have some by the fact that it stands so close to the resemblance to the Anaptomorphidae or more typical anaptomorphids, and so far Tarsioidea, to which they have usually been from Tarsius, in time and in space.1 referred, but it is more probable that they INCERTAE SEDIS.-Periconodon, based on are lemuroids allied to or belonging in the a single specimen with PI and Ml-2, per- Adapidae. Megatarsius, from the German haps belongs in or near one of the above Middle Eocene, does not appear to be an groups, but cannot be even provisionally anaptomorphid and is incertae sedis, al- placed at present. Phenacolemur, Trogole- though a primate and more or less tarsioid mur and Uintasorex cannot be placed in in aspect. Microtarsioides, from the same this family with any assurance nor, a deposit, is also tarsioid in general impres- fortiori, in any subfamily of it. It is pos- sion, but of quite uncertain affinities. sible that they represent two aberrant Yumanius was considered by Stock to branches from a Paromomys-like ancestry. belong with the "Euryacodon-Anaptomor- At present it is difficult to assign them any phus stock," hence in the Anaptomorphinae definite taxonomic rank or position. Their of my arrangement, but its method of para- resemblances are so confusing and they are conid reduction is different, the heel of M3 so poorly known that it seems unwarranted is likewise very different, and the distinc- to base separate families on them, and yet tive premolars and more anterior teeth are they are too distinctive to enter with any unknown. It seems necessary, therefore, reasonable probability into one of the es- to consider it as an anaptomorphid incertae tablished families. sedis until more completely known. VI.-RELATIONSHIPS OF PALEOCENE AND EOCENE PRIMATES There are now about 50 or 55 known Notharctus, Adapis, Tetonius, valid genera of Paleocene and Eocene pri- and Necrolemur, as well as the Oligocene mates. Of these, the skeleton is well Sinclairella, which belongs to an Eocene known only in Notharctus. Much of the group. Considerable but imperfect parts skeleton is known in Megachiromyoides, of the skull are also known in Aphanolemur Microtarsioides and Ceciliolemur, but pre- (but its teeth are unknown), Europolemur, served in such a way as to leave obscure Megatarsius, Microtarsioides, Pseudoloris many of the most desirable details. Im- and Ceciliolemur. Knowledge of the other portant parts of the skeleton are also known genera is mostly confined to the dentition, in Plesiadapis, Adapis, Hemiacodon, Ne- jaws and in a few instances (e.g., Stehlin- crolemur and Pseudoloris, and a few rela- ella) inconsiderable parts of the skull adja- tively unimportant fragments in other cent to the upper jaw. genera. Good skulls are known only in In view of the general rarity and fragility 1 Pseudoloris and Necrolernur show considerable of these small and ancient animals, this is resemblance which may represent special phyletic a good showing, but it is clear knowl- connection or may be merely of somewhat generalized that anaptomorphid character. The latter is true if, edge sufficient for really well-founded as seems possible, Necrolemur is from a paromomyine and Pseudoloris from an omomyine ancestry. If, opinion as to affinities is available for only however, Pseudoloris abderhaldeni and Necrolemur a few genera, especially: raabi from the Geiseltal (see Weigelt, 1933) are cor- rectly placed, these two genera became differentiated only at the end of the Middle Eocene, and subfamily Adapis distinction is not warranted. But it seems almost Notharctus certain that these two species belong to one genus, Pronycticebus which is Pseudoloris or a very close ally and not Necrolemur. Indeed their specific separation is Necrolemur questionable. Tetonius Ono Bulletin A"merican Museum of Natural-History [Vol. LXXVII

With less secure but still fairI good data and to wait indefinitely for better material. for: I believe, however, that it is preferable for Plesiadapis each student acquainted with any consid- Pseudoloris Hemiacodon erable part of the data to attempt some (Sinclairella) systematic grouping at frequent intervals. How confusing the evidence is, even Many errors are inevitably involved, but when data are available, is well shown by surely it is better to interpret the evidence the case of Pronycticebus, which was until actually available as best one can, accept- recently generally agreed to be a tarsioid ing correction with good grace when it nearly allied to Omomys, but which has comes, than simply to discard as inade- now been found (by Le Gros Clark, 1934) quate these priceless earliest records of that to be a lemuroid related to Adapis. If a part of mammalian history of most imme- genus known from the nearly complete diate interest to our species. The accres- skull and dentition is thus difficult to place, cence of interpretation and theory is as es- it is obvious that no opinion can carry sential to the achievement of knowledge as much weight regarding the great majority is the accumulation of the raw materials of established genera. If they have a very from which these arise, and isolated obser- marked dental resemblance, approaching vations of fact have little value until some identity, with a genus that is classified on progress has been made toward their inte- strong grounds, they can be placed with gration. considerable probability, but otherwise Possible groupings among Paleocene and they must remain of very doubtful affinities. Eocene genera are of two general sorts. Some genera have such generalized or In some cases there appear to be approxi- such apparently synthetic or eclectic denti- mate phyletic or structural lines of succes- tions that it is practically impossible to sive related genera, such as the Labidole- place them at all, or even to be quite cer- mur - Teilhardella - - Stehlinella- tain that they are primates. There are, Sinclairella line so well worked out by Jep- however, certain more specialized dental sen. In other cases the grouping can only types that characterize groups of genera, be of a number of contemporaneous or and it is possible to use these to form enti- nearly contemporaneous genera that are ties of varying size, each including a num- divergent but that suggest origin from a ber of forms that are probably related to common ancestor, such as the Omomys- each other. It is thus possible to form a Teilhardina - Loveina - Hemiacodon - working system for most of the Eocene Washakius-Shoshonius-Navajovius group. primates, among themselves. The deter- This is, of course, the familiar distinction mination of the relationships of these between vertical and horizontal classifica- groups to larger categories, however, or to tion. The early primates cannot now be Recent primates, and their insertion in a classified consistently by either method general, formal, Linnaean taxonomy are alone, but necessarily involve a compro- much more difficult and much less reliable. mise and combination between the two. For example, it can hardly be doubted that the genera Elphidotarsius, Carpodaptes Adapidae and Carpolestes are closely related to each By far the best known, although not the other and form a closed and natural group. most clearly defined, group of Eocene pri- But their superfamily position is a prob- mates is that including at least the genera lem to which there is now no wholly satis- Protoadapis, Pronycticebus and Adapis in factory solution. Europe and , Notharctus and Faced by these serious difficulties and the Aphanolemur in North America. Notharc- certainty of falling into error in attempting tus has been studied by Gregory (especially to overcome them, it might seem better 1920) in such careful detail that it is among simply to leave all the early primates, with the best known of all fossil and the possible exceptions of the few better Stehlin (especjially 1912) has rendered a known genera listed above, as incertae sedis similar service with regard to the less com- Fig. 8. Pronycticebus gaudryi. Type skull in Museum d'Histoire Naturelle, Paris. Superior, left lateral and palatal views. One and one-half times natural size. (Opportunity to insert the first published photographs of this important and unique type is due to the kindness of Dr. J. Piveteau, who sent them to Dr. W. E. Le Gros Clark for publication, and to Dr. Le Gros Clark, who was unable to include them in his study of the genus and has sent them on for inclusion in this paper.) 201 202 Bulletin American Museum of Natural History [Vol. LXXVII

pletely preserved remains of Adapis. As is really an adapid, it becomes probable they have shown, Notharctus and Adapis that Anchomomys is too. Le Gros Clark are both basically lemuroid in structure suggests (1934, p. 26) that the adapine skull and typify two lines that must have di- structure of Pronycticebus contradicts the verged in the Paleocene, although their evidence of tarsioid affinities provided by common ancestry has not been discovered. the dental resemblance to Anchomomys, Pelycodus is closely related and probably but I do not feel that this is a contradiction. ancestral to Notharctus. Aphanolemur, On the contrary, reference of both genera known only from a toothless skull frag- to the Adapidae clears up several anomalies. ment, is evidently an adapid but of un- The dentition of Anchomomys is not con- certain closer affinities. Protoadapis, al- vincingly tarsioid. Like Caenopithecus and though not well known, seems to be closer Pronycticebus, it has dental characters that to Notharctus than to Adapis, despite its would be unique among tarsioids but that European provenience. Pronycticebus is are normal or even diagnostic for adapids. clearly closer to Adapis, although aberrant Although Stehlin and some others tend in some respects and in others conservative to class Adapis and Notharctus in two as compared with the latter (Le Gros Clark, families, Gregory has suggested that they 1934). might better be held as typical of two sub- Caenopithecus is usually classified as a families of Adapidae. The difficulty of tarsioid, in the Anaptomorphidae or Tarsi- assignment of some related genera to one idae, but I would associate it provisionally group rather than the other is a further with the Adapidae. Stehlin (1916) has practical reason for preferring this arrange- shown that its anterior dentition is diver- ment. The best provisional classification gent from that of Adapis but that the molar of these genera at present thus seems to be: structure shows, on the whole, close analo- Adapidae gies with Adapis or the Adapidae in gen- Adapinae: Adapis, Pronycticebus, Anchomo- dental formula com- mys. eral. The suggests Perhaps Aphanolemur and Caeno- parison only with Tarsius, but Stehlin goes pithecus, which are otherwise on to say, and all must agree, that this by Adapidae incertae sedis. no means signifies necessarily close rela- : Pelycodus, Notharctus, Proto- tionship to the Eocene forerunners of adapis. Tarsius and he also emphasizes the pres- Both subfamilies appear to be poly- ence of distinctly non-tarsioid characters. phyletic in detail, but their divergent phyla Caenopithecus is very distinctive, wherever are not yet adequately traced. The family it be placed, but it is less anomalous as an as a whole is surely lemuroid and probably adapid than as a tarsioid. It has, for in- includes, or at least is very near, the actual stance, the open trigonids, and the peculiar ancestry of the modern lemurs in a strict mode of paraconid reduction so characteris- sense. It may not be very distant from tic of Adapis and its close allies and un- the ancestry of all lemuroids or even of the known among any forms of really probable higher primates. tarsioid affinities. As always, such dental evidence may be misleading, but it is all we Plesiadapidae have and it does favor reference to the The plesiadapids and apatemyids have Adapidae. often been confused, but Jepsen (1934) has Anchomomys has also been referred, al- now clearly shown that the two groups are most without question, to the tarsioid quite distinct. The genera referable to group, but this was done largely because of the Plesiadapidae are Pronothodectes, Plesi- its resemblance to Pronycticebus.' Now adapis, Chiromyoides, Platychoerops, and that Le Gros Clark has shown, in a manner Megachiromyoides. The morphological, entirely convincing to me, that Pronycticebus temporal and spatial relationships of these 1 In fact the argument has been used both ways genera are summed up in the following in most illogical fashion: Anchomomys is a tarsioid because it resembles Pronycticebus and Pronycticebus diagram, which roughly approximates a is a tarsioid because it resembles Anchomomys. Yet phylogeny but cannot be claimed as such in neither convincingly resembles any genera known surely to be tarsioids. detail: 1940] Simpson, Studies on the Earliest Primates 203

Age North ALmerica Europe Middle Megachiromyoides Eocene Lower Cf. Ple8iadapis Platychoeropz Upper Plesiadapis Chiromyoides Paleocene Middle Pronoth(odectes The recent discovery (Weigelt, 1933) of Megachiromyoides, based on a very poor Apatemyidae skull, good lower jaws, forelimbs, and much of the vertebral column, has greatly added Stehlin (1916) pointed out the similarity to knowledge of this family.' between Plesiadapis (and Chiromyoides) The affinities of this family have long and Heterohyus (with its allies or synonyms) been disputed. It has been referred to the but did not definitely unite them in one Insectivora and to the Rodentia, but its family. When Matthew (1915) described primate affinities are now indisputable. "Nothodectes" he did not immediately Within the Primates, Stehlin (who did not recognize its European affinities and re- differentiate it from the Apatemyidae), be- ferred it to his family Apatemyidae, de- lieved that it was closely related to Dauben- scribed a few years before (1909). Later tonia, and this opinion was widely accepted. Matthew (1917) recognized the close simi- On the basis of the dentition and much of larity (identity according to subsequent the skeleton of Plesiadapis, I have, how- students) of "Nothodectes" and Plesiadapis, ever, shown (1935) that there is no valid and he united the families Plesiadapidae evidence of special relationship to Dauben- and Apatemyidae under the former name, tonia but that the family is probably an but excluded Heterohyus (etc.). Teilhard early offshoot of a definitely lemuroid (1921) united Heterohyus (and also the stock, not leading clearly to any known mixodectids) with these and included all later forms. in the recent family "Chiromyidae" (Dau- Although Weigelt accepted Stehlin's bentoniidae). It was, however, suspected general view as to daubentonioid affinities, by most students that two or more distinct Megachiromyoides seems to me to agree phyla were confused in these various group- with and to reenforce my previous opinion. ings. Knowledge of the group was sig- It is a remarkably specialized genus sug- nificantly increased by the discovery of gestive of the termination of a strongly Stehlinella (Matthew, 1921), Labidolemur aberrant lemuroid phylum. It does not, as (Matthew and Granger, 1921, Simpson, the alternative theory would expect or de- 1929, 1935), Teilhardella (Jepsen, 1930) mand, show any definite trend in a direc- and Sinclairella (Jepsen, 1934), and on this tion from Plesiadapis toward Daubentonia, basis Jepsen (1934) was able to separate but only an intensification of characters the Apatemyidae clearly from the Plesi- not or manifestly only superficially dauben- adapidae. As thus redefined, the Apate- tonioid. myidae form an undoubtedly natural Age North America Europe Oligocene Lower Sindairella Upper Stehlinella Heterohyus I Eocene Middle Apatemy8 Heterohyu8 Lower Teilhardella Eochiromy8 Upper Lab%dolemur_--? Paleocene I Middle Jepsenella i Copies of publication did not reach us until after JepsenWeigelt'shad written his important study group, which may be retained as of family of the Apatemyidase (1934) and I my discussion of rank, with the structural sequence shown Plesiadapis (1935) so that Megachiromyoides is not considered in those papers. m the diagram. 204 Bulletin American Museum of Natural History [Vol. IXXVII

The two geographic groups are not as ancestry of Daubentonia is true, it is prob- distinct as might be suggested by this ar- ably true only of the Apatemyidae and not rangement, and are not now distinctly of the Plesiadapidae. Even as regards the definable as separate phyla. Apatemyidae it seems at present almost These eight genera show many differ- entirely hypothetical. Jepsen says that ences, chiefly in the way of evolutionary Sinclairella has no structures to link it with advances from Paleocene to Oligocene, Daubentonia, but does not compare the two but they are clearly related to each other. in explicit detail. There is now little more Their relationships to other mammals are to do with the apatemyids than to call them dubious in the extreme. No skeletal parts ?Primates jncertae sedis. If it were neces- are known, but the snout of Stehlinella and sary to frame a more definite hypothesis, most of the skull of Sinclairella have been mine would be, purely as a hypothesis, that found. Unfortunately these are the two the apatemyids might be an aberrant, ster- most specialized genera. Matthew (1921) ile offshoot of the undifferentiated and said of Stehlinella that it "has no especial probably formally proto-lemuroid primate suggestion of primate about it; but that ancestry. Such a stock seems to have is of little significance." He referred it to existed in the Paleocene and to have been the Plesiadapidae, which he believed, on differentiating rapidly into many different grounds not affected by Stehlinella, to in- lines of which only a few were destined to clude tupaioid insectivores near the boun- survive into the later Tertiary and Recent. dary line of the primates. Jepsen (1934) On the other hand, the apatemyids may placed Stehlineltla and Sinclairella in the prove to have nothing to do with the pri- Apatemyidae, where they clearly belong, mates. and said that they "have few characters to justify placing the family in any known Carpolestidae order of mammals. Those structures which This small but highly distinctive family indicate Primate relationships are con- is known at present only by three genera, tradicted by others, equally convincing, to all American, in the Middle and Upper place the family elsewhere." He pro- Paleocene: visionally followed Matthew in referring Carpolestes the family to the Insectivora as an artifice Upper subject to revision. He did not make de- Paleocene Carpodaptes tailed comparisons with other mammals except to contrast the dentition with that Middle Elphidotarsius of the Plesiadapidae. The consensus is that these strange animals are primates- Carpodaptes and Carpolestes are closely such would be Matthew's opinion, also, if similar and nearly contemporaneous, prob- he agreed to draw the insectivore-primate ably partly overlapping in distribution, but boundary below rather than above the Carpolestes is slightly more specialized. tupaioids as Le Gros Clark and some other Only jaws and teeth are known. more recent authorities do. The factual Despite their extraordinary premolar basis for reference of the apatemyids to the specialization, the teeth of these genera Primates is, indeed, slight and faulty, but have many characters common in early it is at least as good as any basis for refer- primates and not definitely known to oc- ing them to the Insectivora and better cur in any other order, and they have no than for reference to any other order. characters typical of any other order. The subject requires further study and, This is not rigid proof that they are pri- especially, discovery. mates, but leaves no reasonable alternative Within the Primates, there are really no to so classifying them unless contrary evi- grounds at present for suggesting the closer dence is later discovered. With differences affinities of the Apatemyidae. If Steh- of detail, the molars are suggestive of those lin's widely quoted theory that the Plesi- of various anaptomorphids, and there is no adapidae plus Apatemyidae are near the theoretical difficulty in deriving the pre- 19401 Simpson, Studies on the Earliest Primates 205, molars also from those of anaptomorphids primates. A few of them, particularly although there is no conclusive evidence Necrolemur, Pseudoloris and Tetonius, show that this really happened. On this basis definite and almost conclusive evidence of Abel (1931, p. 199) united the carpolestids special relationship to Tarsius. Even with some of the anaptomorphids, includ- these genera, however, have some charac- ing Anaptomorphus itself, under the name ters making a closer approach to the true "Tetoniidae" (= Anaptomorphidae, a lemuroids than is seen in the living form. name with almost fifty years' priority). Hemiacodon in its skeleton shows a curious This collocation is not clearly invalid, but blend of lemuroid, tarsioid and aberrant it does not seem to me sufficiently well characters, with the balance inclining rather grounded at present for acceptance. The toward the lemuroids. Most of the genera family as so constituted is defined only by referred to the Anaptomorphidae have been the presence of enlarged P44, but this is an considered to be tarsioids principally be- adaptive character requiring co6rdination cause of dental resemblances or linking by with stronger, more numerous and more apparently annectent types to the three particular other resemblances before it can genera known to be tarsioid. Even in the be considered as significant in this sense. dentition, however, some genera, such as The mere enlargement is not accompanied Paromomys, have some evidently lemuroid by true and exclusive structural similarity. characters, although the balance here Elphidotarsius, along with other evidence, favors closer alliance with known tarsioids. indicates almost certainly that a common The family as now constituted is clearly ancestor of Carpolestes and Tetonius would heterogeneous although it could be natural have P44 much as in Paromomys or indeed in having arisen from one origin. It in- almost any very primitive primate and I cludes many different minor phyla. As cannot agree that any special affinity is far as these can be definitely placed, they indicated, as opposed to possible generally show affinities with the tarsioids. It is, tarsioid affinities for all these genera. however, quite possible that some of the Even this degree of affinity is not strongly less well-known phyla now placed here will supported by the known facts, although later demand separation and some may they do not more definitely suggest any prove not to be truly tarsioid in affinities. other. There is a remarkably close re- semblance in the lower molars between Primates incertae sedis carpolestids and plesiadapids, but it does The three American genera Phenacole- not extend to all parts of the dentition and mur, Trogolemur and Uintasorex are prob- may indicate nothing more than that all ably primates, but are of wholly uncertain are early primates. The same is true of a position within that order. Because of somewhat more distant resemblance to the some adaptive characters, they are some- adapids. On the whole it is suggested that times referred to the Plesiadapidae, or to the carpolestids may be another sterile off- the Apatemyidae, but as Jepsen and others shoot of the poorly differentiated more or have suggested this cannot be accepted if less broadly lemuroid proto-primate stock, those families are bounded in any way at probably somewhat nearer to the tarsioids all likely to be natural. All three of these than to the lemuroids in a strict sense. genera might be derived from a more or less Paromomys-like ancestry, which in Anaptomorphidae turn might or might not warrant their in- The tentative contents and proposed clusion in the Anaptomorphidae (to which subdivision of the Anaptomorphidae have they would add two or three very distinc- been discussed in a previous section of tive phyla), but all this is too uncertain these studies. Here some remarks on the now to be of any real use. nature and affinities of the family as a whole In addition to several definitely classifi- may be added. able and important forms, Weigelt (1933) There is little or no doubt that all the has described four Primates incertae sedis genera now referred to this family are true from the German Middle Eocene: Europo- 206 Bulletin American Museum of Natural History [Vol. LXXVII lemur, Megatarsius, Microtarsioides and as far as known. The systematic position Ceciliolemur. All of these are based on of the genus is wholly uncertain. relatively complete material, but preserved Ceciliolemur is represented by a nearly in such a way as to leave many essential complete skeleton, with fairly good limb details obscure. gross structure but the skull very poor and Europolemur is based on a badly crushed the dental patterns almost unknown. skull with complete upper dentition. As Weigelt erects for the genus a new family Weigelt has shown, it seems to be definitely and a new group Ceciliolemuroidea. This lemuroid, but does not compare very closely is defined essentially as including primitive with Adapis. Common ancestry with the primates with no primate characters. Adapidae would probably have to be re- There are, however, a few suggestions of mote, somewhere in the Paleocene, and primate affinities, as Weigelt shows, al- definite reference to that family is not though none warranting positive reference probable. In some respects Europolemur to that order. Truly diagnostic features seems to be closer to the living lemuroids are in part vague and in part unknown, than are the adapids. and the proposed Ceciliolemuroidea can hardly be clearly recognized at present as Megatarsius is also based on a skull, but against various groups of very primitive in still worse preservation and with only primates or of insectivores. The anterior the canine and MI-3 clearly preserved. dentition seems to be less modified than in There is some resemblance to Periconodon, most lemurs or tupaioids, but probably but not identity, and Periconodon is not only two incisors are present. The skele- wholly certain as to position. The general ton is very primitive and insectivore-like, aspect is rather tarsioid, but not clearly but the observed details refer more to mat- enough to make reference to that group ters of proportion and other superficial clear. features than to characters that give much Microtarsioides is represented by a skull insight as to broader affinities. The genus and much of a skeleton, but all so poorly may be a tupaioid in a broad sense, despite preserved that few important details stand a few observed differences from Tupaia, out. The crown patterns of the teeth are or it may indeed belong to some distinct not shown. The aspect is only vaguely but as yet really undefinable ancient pri- tarsioid. It is probable that the calcaneum mate or primate-like group, or it may be an is not elongated as it is in all true tarsioids, insectivore of some sort.

VII.-DISTRIBUTION OF PALEOCENE AND EOCENE PRIMATES From the geographic and phyletic rela- Middle Huangho Valley, a horizon now re- tionships of the European and American garded as uppermost Eocene or lowest forms, it is inferred with considerable prob- Oligocene. Hoanghonius, based on a jaw ability that Asia was an important early fragment with M2_3, is from the same hori- Tertiary center of evolution for the pri- zon and locality. Its affinities are wholly mates, perhaps even their place of origin uncertain and I am inclined to doubt its and primary differentiation. At present being a primate. Anagale, a genus based this is entirely theoretical, however, because on excellent knowledge of skull, jaws and no Paleocene or Eocene primates have yet part of the skeleton, is a tupaioid from the surely been identified from Asia. The Ulan Gochu, Lower Oligocene, of Mongolia. earliest possible Asiatic primates are Its reference to the Primates depends on Hoanghonius, Adapidium and Anagale. that of the Tupaioidea. I would now Hoanghonius, very imperfectly known, is follow Le Gros Clark in referring all the probably a primate and has some resem- tupaioids, including Anagale, to the Lemu- blance to early tarsioids, but is really of roidea, but in any case Anagale is well off unknown affinities. It is from the "River the main line of primate descent and is not Section" of the Yuanchu Series in the clearly related in any special way to known 1940] Simpson, Studies on the Earliest Primates 207

Eocene forms. Aside from these three rec- quired in the course of slow infiltration ords, the oldest known Asiatic primates southward along the length of Central and are from the Miocene and already belonged South America. to specialized modern groups. In North America primates first appear In Africa the first known primates occur in the Middle Paleocene, where they are in the Oligocene. They are primitive already differentiated into Anaptomor- within their groups, but they belong to phidae (Paromomyinae), Plesiadapidae, higher types still extant and are quite un- Carpolestidae, Apatemyidae. The Adap- like the Paleocene and Eocene forms. Lack idae appear in the Lower Eocene, com- of early Tertiary records makes it impos- pleting the roster of known families. Anap- sible to judge when the lemuroids, now so tomorphids and adapids were relatively characteristic of Africa, entered that con- abundant and the former were highly differ- tinent and whether it played any other role entiated in the Lower and Middle Eocene, in their history than that of an asylum for but they are rare in the Upper Eocene in relicts and a scene of secondary radiation. America. In the American Lower Oligo- Africa certainly has had an important part cene an apatemyid and a possible anapto- in the deployment of some of the higher morphid are known from one specimen primates, but its connection with Paleocene each.' No later North American pri- and Eocene primate history cannot even be mates are known until the coming of man. inferred reasonably until fossils of those The European Paleocene is very poorly ages are found. known, and only plesiadapids have been In South America the oldest known pri- found. In the lower Eocene, however, mates occur in the late Oligocene or early there are all the families known in the Miocene, supposed older records having American Lower Eocene, Plesiadapidae, been shown to be probably erroneous as to Apatemyidae,Anaptomorphidae and Adap- identification or as to assigned age. These idae. All of these still occurred in the first records are of primates already of European Middle Eocene and all but the typically South American type and com- Plesiadapidae in the Upper Eocene. On bined with later and Recent forms they present evidence it appears that Plesia- indicate that South America's role in pri- dapidae and Adapidae survived longer in mate history has been a simple one. As Europe than in America and the Apatemyi- far as known, that area received some dae almost (perhaps quite) as long. Car- primitive, more or less unified stock of pri- polestidae are not yet known from Europe, mates which radiated over the isolated perhaps only because of inadequate knowl- continent and had no further connection edge of the Paleocene there. Like other with primate history in general. Gregory mammals, the primates show close connec- has shown that it is probable that this tion between America and Europe in the original stock was adapid (notharctine) or Lower Eocene and increasing divergence in something closely allied to those ancient the later part of the epoch. There is a sharp lemuroids. It is not impossible but is break in European primate history at the unlikely that primates were present in what end of the Eocene and none of the groups is now Patagonia during the Paleocene and then present can be traced with any clarity Eocene. It seems to me probable that into known later forms. they did then occur in central or northern The distribution of the recognized fami- South America, but Paleocene and Eocene lies and subfamilies and of all the genera mammals have yet to be discovered in those considered valid is shown in the accom- regions. There is a long gap both in time panying table, in which A represents known and in morphology between possible ceboid occurrence in North America and E in ancestors in the North American early Europe. Similar tabulations have recently Tertiary and true ceboids in the Patagonian 1 After this paper had been submitted for publica- middle Tertiary, and I suspect, as almost tion, the discovery of an American Oligocene anapto- pure speculation, that the time was oc- morphid, was announced, without any published de- tails (Clark in Bull. Geol. Soc. Amer., L, p. 1963, cupied and the morphologic changes ac- December, 1939). 208 Bulletin American Muse uum of Natural History [Vol. LXXVII been published by several authors, espe- some still more recent work and discovery, cially Abel (1931) and Weigelt (1933), but and involve some errors here corrected, they do not follow the classification here especially regarding the ages of American suggested, do not include the results of genera.'

Paleo- Paleo- cene Eocene cene Eocene 2a 12 -e~'12 t-.I a 'I a 1 Adapidae AE AE E Omomyinae A AE A Adapinae E E Navajovius A Adapis E E Teilhardina E Pronycticebus E Loveina A Anchomomys E E Shoshonius A Notharctinae AE A Omomys ?A A Pelycodus A Hemiacodon A Notharctus A A Washakius A Protoadapis E Chumashius A Adapidae inc. sed. Dyseolemur A Caenopithecus E Aphanolemur A Anaptomorphinae A A Plesiadapidae A AE AE E Absarokius A Pronothodectes A Tetonius5 A Plesiadapis AE ?A Anaptomorphus ?A A Chiromyoides E EuryacodonW A Platychoerops E Uintanius A Megachiromyoides E Necrolemurinae E E Apatemyidae2 A A AE AE AE Necrolemur E E Jepsenella A Microchoerus E Labidolemur A Teilhardella A Pseudolorisinae E E Eochiromys E Pseudoloris E E Apatemys A Anaptomorphidae inc. sed. Heterohyus3 E E Periconodon E Stehlinella A Nannopithex E Carpolestidae A A Yumanius A Elphidotarsius A Carpodaptes A Family uncertain Carpolestes A Phenacolemur7 A A Anaptomorphidae4 A A AEIAE E Trogolemur A Paromomyinae A ?A Uintasorex A Palenochtha A Europolemur E Palaechthon A Megatarsius E Plesiolestes A Microtarsioides E Paromomys A Ceciliolemur E

1 For instance, Abel gives Plesiolestes as Lower 2 Also in the Lower Oligocene of North America, Paleocene and Pronothodectes, Palaechthon, Elphido- Sinclairella. tarsius and Paromomys as Upper Paleocene-all are 3 Amphichiromys, Heterochiromys and Necrosorex really from the Middle Paleocene. Weigelt lists are synonymous with or very close to Heterohyus the European genus Protoadapis as North American and are not listed separately. and gives Paleocene to Upper Eocene for the dis- 4 Also in the Lower Oligocene of North America tribution of the Notharctinae (really Lower to Middle (Clark). Eocene). It is almost impossible to eliminate such 6 The Upper Paleocene specimen referred to errors entirely from a tabulation and perhaps mine Tetonius belongs to Plesiadapis. still includes some despite the advantage of having 6 Euryacodon is probably the upper dentition of Abel's, Weigelt's and others' work as a point of de- Anaptomorphus but is tentatively listed. parture. 7 lynacius is a synonym of Phenacolemur. 19401 Simpson, Studies on the Earliest Primates 209 VIII.-INDEXED BIBLIOGRAPHY OF PALEOCENE AND EOCENE PRIMATES The references given here include all these in turn refer back to all the older those explicitly cited in the preceding notes literature. Search for original information and also a selected bibliography of the sub- on each genus here recognized as valid is ject. The bibliography is brief, yet the facilitated by the following index, in which titles chosen include most of the important the genera are listed alphabetically, with recent literature and give access to essen- author and date for each name, followed tially all original work on these early pri- in parentheses by references to those titles mates. The most recent and best illus- in the bibliography that are of special trated accounts of each genus are cited, and importance for the given genus.

BIBLIOGRAPHY

ABEL, 0. JEPSEN, G. L. 1931. "Die Stellung des Menschen im Rah- 1930a. "Stratigraphy and paleontology of men der Wirbeltiere." Jena. [Re- the Paleocene of northeastern Park view of all fossil primates then known. ] County, Wyoming." Proc. Amer. CLARK, W. E. LE GROs. Phil. Soc., LXIX, pp. 463-528. 1934a. "Early forerunners of man." Bail- [Plesiolestes pp. 505-506, Phenacole- liere, Tindall and Cox: London. mur pp. 514-515, Plesiadapis pp. 1934b. "On the skull structure of Pronyctice- 515-517 and 525-528, Carpolestes pp. bus gaudryi." Proc. Zool. Soc. Lon- 520-524.] don, 1934, pp. 19-27. 1930b. "New vertebrate fossils from the GIDLEY, J. W. Lower Eocene of the Bighorn Basin, 1923. "Paleocene primates of the Fort Wyoming." Proc. Amer. Phil. Soc., Union, with discussion of relationships LXIX, pp. 117-131. [Teilhardella, pp. of Eocene primates." Proc. U. S. 126-127.] Nat. Mus., LXIII, pp. 1-38. [Paromo- 1934. "A revision of the American Apatemyi- mys, Palaechthon (includes Palenoch- dae and the description of a rxew tha), Elphidotarsius, Pronothodectes.] genus, Sinclairella, from the White GRANGER, W. River Oligocene of South Dakota." 1910. "Tertiary faunal horizons in the Wind Proc. Amer. Phil. Soc., LXXIV, pp. River Basin, Wyoming, with descrip- 287-305. [Sinclairella, also notes on tions of new Eocene mammals." all apatemyids then known.] Bull. Amer. Mus. Nat. Hist., XXVIII, LooMIs, F. B. pp. 235-251. [Shoshonius, pp. 249- 1906. "Wasatch and Wind River Primates." 250.] Amer. Jour. Sci., (4), XXI, pp. 276-285. GRANGER, W., AND GREGORY, W. K. [Anaptomorphus, Pelycodus; note that 1917. "A revision of the Eocene primates none of the specimens placed in of the genus Notharctus." Bull. Amer. Notharctus belong there: "N." minutus Mus. Nat. Hist., XXXVII, pp. 841- is ?Omomys minutus and the others are 859. [Notharctus, Aphanolemur.] not primates; Anaptomorphus abbotti GREGORY, W. K. was later made type of Absarokius by 1920. "On the structure and relations of Matthew.] Notharctus, an American Eocene pri- MATTHEW, W. D. mate." Mem. Amer. Mus. Nat. 1909. "The Carnivora and Insectivora of Hist. (N.S.) III, Pt. II, pp. 49-243. the Bridger Basin, Middle Eocene." [Pelycodus, Notharctus, Adapis and Mem. Amer. Mus. Nat. Hist., IX, Pt. allied genera.] VI, pp. 291-567. [?Primates, pp. 1922. "The origin and evolution of the 543-546; Apatemys, Uintasorex, Tro- human dentition." Baltimore. [Re- golemur. ] views all genera then known; new 1915. "A revision of the Lower Eocene figures of Necrolemur.] Wasatch and Wind River faunas. HELLER, F. Part IV.-Entelonychia, Primates, 1930. "Die Saugetierfauna der mitteleozanen Insectivora (part)." Bull. Amer. Braunkohle des Geiseltals bei Halle Mus. Nat. Hist., XXXIV, pp. 429- a.S." Jahrb. Hall. Verb. (N.F.) IX, 483. [Lower and Middle Eocene pp. 13-41. [Heterohyus, Adapis, Primates, pp. 433-465, 477-483; Pely- "Necrolemur" raabi (Pseudoloris?), codus, Notharctus, Omomys, Hemia- Periconodon. ] codon, Washakius, Shoshonius, Uin- 210 Bulletin American Mu,tSeeum of Natural History [Vol. LXXVII

tanius, Anaptomorphus, Tetonius, Ab- 1937a. "The Fort Union of the Crazy Moun- sarokius, Trogolemur, Phenacolemur, tain Field, Montana, and its mam- Nothodectes (= Plesiadapis).] malian faunas." U. S. Nat. Mus., 1917. "The dentition of Nothodectes." Bull. Bull. 169, pp. i-x, 1-287. [Paromo- Amer. Mus. Nat. Hist., XXXVII, mys, Palaechthon, Palenochtha, Elphi- pp. 831-839. [Plesiadapis.] dotarsius, Pronothodectes, Plesiadapis; 1921. "Stehlinius, a new Eocene insectivore." pp. 141-169.] Amer. Mus. Novitates, No. 14, pp. 1937b. "Additions to the Upper Paleocene 1-5. ["Stehlinius" = Stehlinella.] faunia of the Crazy Mountain Field." MATTHEW, W. D., AND GRANGER, W. Amer. Mus. Novitates, No. 940, 1921. "New gernera of Paleocene maimmals." pp. 1-15. [Carpodaptes, pp. 5-9.] Amer. Mus. Novitates, No. 13, pp. STEHLIN, H. G. 1-7. [Primates, pp. 4-6; Labidole- 1912. "Die Silugetiere des schweizerischen mur, Ignaciuis (= Phenacolemur), Eozans, 7. Teil, 1. Hilfte. Adapis." Navajovius, Carpodaptes; brief diagno- Abh. Schweiz. Pal. Ges., XXXVIII, ses only, for descriptions see Simpson, pp. 1165-1298. [Adapis, Protoada- 1935.] pis. ] 1916. "Die Saugetiere des schweizei ischen- SCHLOSSER, M. Eozitins, 7. Teil, 2. Caeno- 1907. "Beitrag zur Osteologie inid sys- Hiilfte. pithecuis - Necrolemur - Micro- tematischen Stellung der Gattunig Necrolemur, Sowie zur Stamnmesge- choerus Nannopithex -Anchomomys -Periconodon - schichte der Primaten iberhaupt." N. Amphichiromys- Jahrb. Min. Geol. Heterochiromys-Nachtr;ige zu Adapis Pal., Festbarnd _Schlussbetrachtungen zu den Pri- 1907, pp. 197-226. [Necrolemur anid maten." Abh. Schweiz. Pal. Ges., allies. ] XLI, pp. 1299-1552. [Besides the SCOTT, W. B., AND JEPSEN, G. L. geniera named in title, Pseudoloris, 1936. "The mammalian fauna of The White Plesiadapis, Chiromyoides and Necro- River Oligocene-Part I. Insecti- sorex which, as well as Amphichiromys vora and Carnivora." Trans. Amer. and Heterochiromys, is now believed Phil. Soc. (N.S.) XXVIII, Pt. I, pp. to equal Heterohyus.] 1-153. [Sinclairella, pp. 26-29.] STOCK, C. SIMPSON, G. G. 1933. "An Eocene primate from California." 1928. "A new mammalian fauna from the Proc. Nat. Acad. Sci., XIX, pp. 954- Fort Union, of southern Montana." 959. [Chumashi us. ] Amer. Mus. Novitates, No. 297, pp. 1934. "A second Eocene primate from Cali- 1-15. [Carpolestes, pp. 7-10.] fornia." Proc. Nat. Acad. Sci., XX, 1929a. "A collection of Paleocene mammals pp. 150-154. [Dyseolemur.] from Bear Creek, Montana." Ann. 1938. "A tarsiid primate and a mixodectid Carniegie Mus., XIX, pp. 115-122. from the Poway Eocene, California." [Labidolemur, pp. 119-120.] Proc. Nat. Acad. Sci., XXIV, pp. 288- 1929b. "Paleocene and Lower Eocene Mam- 293. [Yumanius.] mals of EuIope." Amer. Mus. Novi- TROXELL, E. L. tates, No. 354, pp. 1-17. [Platychoer- 1923. "The Apatemyidae." Amer. Jour. ops, pp. 11-12; Eochiromys, pp. Sci., V, pp. 503-506. [Apatemys 12-13.] only. ] 1931. "A new insectivore from the Oligo- TEITLHARD DE CHARDIN, P. cene, Ulan Gochu horizon, of Mon- 1916-1921a. "Sur quelques primates des golia." Amer. Mus. Novitates, No. phosphorites de Quercy." Annales 505, pp. 1-22. [Anagale. ] Paleont., X, pp. 3-20. [Pseudoloris, 1935a. "The Tiffany fauna, Upper Paleo- Anchomomys, Microchoerus, Necrole- cene II.-Structure and relationships muor. ] of Plesiadapis." Amer. Mus. Novi- 1916-1921b. "Les maminiferes de l'cocene tates, No. 816, pp. 1-30. inf6rieur fraingais et leurs gisements." 1935b. "The Tiffaiy fauna, Upper Paleocene. Aninales Paleonlt., X, pp. 171-176, III. Primates, Carnivora, Condylar- XI, pp. 1-108. [Plesiadapis, pp. 12-17, thra, arid Amblypoda." Amier. Mus. 43-44, 51-55 (= Platychoerops); Pro- Novitates, No. 817, pp. 1-28. [Plesi- toadapis, pp. 58-59, 88-90; Heterohyus, adapis, Labidolemur, Carpodaptes, pp. 81-88.] Navajovius, Phenacolemur; pp. 1-19.] 1927. "Les mamrnifre&s de l'eocene in- 1936. "A new fauna from the Fort Union of f6rieur de la Belgique." Merni. Mus. Montarna." Amer. Mus. Novitates, Roy. Hist. Nat. Belgique, No. 36. No. 873, pp. 1-27. [Plesiadapis, ["Omomys" belgicus (Teilhardina), pp. Carpodaptes, Phenacolematr; pp. 19- 16-18; Plesiadapis, pp. 13-14; Eochiro- 23.] mys, pp. 14-16.] 1940] Simpson, Studies on the Earliest Primates 211

WEIGELT, J. WORTMAN, J. L. 1933. "Neue Primaten aus der mitteleozianen 1903-1904. "Studies of Eocene Mammalia (oberlutetischen) Braunkohle des Gei- in The Marsh Collection, Peabody seltals." Nova Acta Leopoldina (N. F)., Museum. Part II. Primates." I, pp. 97-156. [Megachiromyoides, Amer. Europolemur, Pseudoloris, Megatarsius, Jour. Sci., XV (1903), pp. 163-176, Microtarsioides, Ceciliolemur. I 399-414, 419-436; XVI (1903), pp. WOOLLARD, H. H. 345-368; XVII (1904), pp. 23-33, 1925. "The anatomy of Tarsius spectrum." 133-140, 203-214. [Omomys, Hemi- Proc. Zool. Soc. London, 1925, II, acodon, Euryacodon, Washakius, Ana- pp. 1071-1184. ptomorphus.] IN]DEX Absarokius Matthew, 1915 (Loomis, 1906; Matthew, 1915) Adapis Cuvier, 1823 (Gregory, 1920; Heller, 1930; Stehlin, 1912, 1916) Anaptomorphus Cope, 1872 (Matthew, 1915; Wortman, 1904) Anchomomys Stehlin, 1916 (Stehlin, 1916; Teilhard, 1916-1921a) Apatemys Marsh, 1872 (Jepsen, 1934; Matthew, 1909; Troxell, 1923) Aphanolemur Granger and Gregory, 1917 (Granger and Gregory, 1917) Caenopithecus Riutimeyer, 1862 (Stehlin, 1916) Carpodaptes Matthew and Granger, 1921 (Matthew and Granger, 1921; Simpson, 1935b, 1936, 1937b) Carpolestes Simpson, 1928 (Jepsen, 1930a; Simpson, 1928) Ceciliolemur Weigelt, 1933 (Weigelt, 1933) Chiromyoides Stehlin, 1916 (Stehlin, 1916) Chumashius Stock, 1933 (Stock, 1933) Dyseolemur Stock, 1934 (Stock, 1934) Elphidotarsius Gidley, 1923 (Gidley, 1923; Simpson, 1937b) Eochiromys Teilhard, 1927 (Simpson, 1929b; Teilhard, 1927) Europolemur Weigelt, 1933 (Weigelt, 1933) Euryacodon Marsh, 1872 (Matthew, 1915; Wortman, 1904) Hemiacodon Marsh, 1872 (Matthew, 1915; Wortman, 1904) Heterohyus Gervais, 1848 (Heller, 1930; Stehlin, 1916; Teilhard, 1916- 1921b) Jepsenella Simpson, 1940 (This paper) Labidolemur Matthew and Granger, 192. (Jepsen, 1934; Matthew and Granger, 1921; Simpson, 1929a, 1935b) Loveina Simpson, 1940 (This paper) Megachiromyoides Weigelt, 1933 (Weigelt, 1933) Megatarsius Weigelt, 1933 (Weigelt, 1933) Microchoerus Wood, 1846 (Stehlin, 1916; Teilhard, 1916-1921a) Microtarsioides Weigelt, 1933 (Weigelt, 1933) Nannopithex Stehlin, 1916 (Stehlin, 1916) Navajovius Matthew and Granger, 1921 (Matthew and Granger, 1921; Simpson, 1938) Necrolemur Filhol, 1873 (Gregory, 1922; Schlosser, 1907; Stehlin, 1916; Teilhard, 1916-1921a) Notharctus Leidy, 1870 (Granger and Gregory, 1917; Gregory, 1920; Matthew, 1915) Omomys Leidy, 1869 (Matthew, 1915; Wortman, 1904) Palaechthon Gidley, 1923 (Gidley, 1923; Simpson, 1937a) Palenochtha Simpson, 1935 (Gidley, 1923; Simpson, 1937a) Paromomys Gidley, 1923 (Gidley, 1923; Simpson 1937a) Pelycodus Cope, 1875 (Gregory, 1920; Matthew, 1915) Periconodon Stehlin, 1916 (Heller, 1930; Stehlin, 1916) Phenacolemur Matthew, 1915 (Jepsen, 1930a; Matthew, 1915; Matthew and Granger, 1921; Simpson, 1935b, 1936) Platychoerops Charlesworth, 1854 (Simpson, 1929b; Teilhard, 1916-1921b) Plesiadapis Gervais, 1876 (Jepsen, 1930a; Matthew, 1915, 1917; Simpson, 1935a, 1935b, 1936, 1937a; Stehlin, 1916; Teilhard, 1916-1921b, 1927) Plesiolestes Jepsen, 1930 (Jepsen, 1930a; Simpson, 1937a) Pronothodectes Gidley, 1923 (Gidley, 1923; Simpson, 1937a) Pronycticebus Grandidier, 1904 (Le Gros Clark, 1934b) Protoadapis Lemoine, 1878 (Gregory, 1920; Stehlin, 1912, 1916; Teilhard, 1916-1921b) 212 Bu lletin American Muserum of Natural History [Vol. LXXVII

Pseudoloris Stehlin, 1916 (Stehlin, 1916; Teilhard, 1916-1921a; Weigelt, 1933) Shoshonius Granger, 1910 (Granger, 1910; Matthew, 1915) Sinclairella Jepsen, 19341 (Jepsen, 1934; Scott and Jepsen, 1936) Stehlinella Matthew, 1929 (Jepsen, 1934; Matthew, 1921) Teilhardella Jepsen, 1930 (Jepsen, 1930b, 1934) Teilhardina Simpson, 1940 (This paper; Teilhard, 1927) Tetonius Matthew, 1915 (Gregory, 1922; Matthew, 1915) Trogolemur Matthew, 1909 (Matthew, 1909, 1915) Uintanius Matthew, 1915 (Matthew, 1915) Uintasorex Matthew, 1909 (Matthew, 1909) Washakius Leidy, 1873 (Matthew, 1915; Wortman, 1904) Yumanius Stock, 1938 (Stock, 1938)

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