Tarsiiform primates have long been regarded as a Laurasian group, with an extensive fossil record in the Eocene of North America and EuropeI and two important but less well-known records from Asia

CL Gazin

D Dashzeveg

DE Russell

DE Savage

EL Simons

Elwyn L. Simons

FS Szalay

M Cartmill

P Schmid

PD Gingerich

R Hoffstetter

Thomas M. Bown

TM Bown

English

Crossref

Afrotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from Africa

Simons, Elwyn L

Bown, Thomas M

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USGS Staff -- Published Research US Geological Survey 1985 A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from Africa Elwyn L. Simons Duke University Thomas M. Bown US Geological Survey Follow this and additional works at: https://digitalcommons.unl.edu/usgsstaffpub  Part of the Earth Sciences Commons Simons, Elwyn L. and Bown, Thomas M., "A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from Africa" (1985). USGS Staff -- Published Research. 205. https://digitalcommons.unl.edu/usgsstaffpub/205 This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USGS Staff -- Published Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. NATURE VOL. 313 7 FEBRUARY 1985 - LETTERS TO NATURE- -- 47s -- . I nls artlcle IS a U S government work, and IS not subject to copyr~ght In the Unlted States A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from Africa Duke University Primate Center, Durham. North Carolina 27705, USA Thomas M. Bown US Geological Survey, Denver, Colorado 80225, USA Tarsiiform primates have long been regarded as  a Laurasian group, with an extensive fossil record in the Eocene of North America and EuropeI4 and two important but less well-koown records from ~ s i a ' . ~ .  The only living genus is Tanius (Tarsiidae), whereas all of the fossil tarsier-like primates are usually placed in the extinct family Omomyidae3. We now report the discovery of Afrotanius chatrathi from early Oligocene rocks of Fayum Province, Egypt. This is the first known tarsiifom primate from Africa. Compared with fossil primates, the molar tooth morphology of this diminutive prosimian is most similar to that of the European Eocene micro- choerine Pseudoloris; however, the closest similarity is to the 476 LElTRS TO NATURE NATURE VOL. 313 7 FEBRUARY 1985 molars of Tanius. Because the phylogenetic relationship among living Tarsius and the omomvids remain unclear7s and because of the fragmentary nature of {he only known specimen of this new primate, allocation of Afrotarsius to either Omomyidae or Tar- siidae is necessarily provisional. As we believe that its molar teeth are more like those of Tarsius than of any omomyids (including Pseudoloris), we tentatively assign the new genus to the extant family Tarsiidae as its only known fossil representative. Recovery of a Tarsius-like primate from Africa suggests that it or its ancestors might bave been immigrants from Europe, may have been derived from an unknown Asian stock related to the ancestry of Tanius, or may have originated in Africa. Order Primates Suborder Prosimii Infraorder Tarsiiformes Family Tarsiidae? Afrotarsius, gen. nov. Type species: Afrotarsius chatrathi, sp. nov. Diagmis: Differs from Tarsius in having a more posteriorly placed entoconid and thereby relatively longer distance between the Mi-, entoconid and metaconid; in having a relatively larger and slightly more labial M2 paraconid; in lacking a distinct entoconid and in having a smaller, less posteriorly extended posterior cusp on M,; and in having M3 with a shorter talonid and a relatively smaller crown with respect to M,. The specimen differs from all anaptomorphine and omomyine omomyids in the combination of labiolingually broad and shelf-like molar paraconids separated from metaconids and protoconids by a deep notch, and from all omomyids in having a raised, wall-like ridge between the entoconid and metaconid (both features as in Tarsius). It differs from all omomyids (except possibly Hemi- acodon and Macrotarsius) in having Mi  metaconid tingually opposite to  protoconid, not placed more posteriorly, and in having a smooth posterior wall on the MI  trigonid. It differs from all omomyids and Tarsius in having an indistinct talonid notch on molars and in having M I  > M, > M3. Afrotarsius chatrathi, sp. nov. Etymology: For Prithijit S. Chatrath, collector of the type and only known specimen. Holotype: CGM (Cairo Geological Museum. Ma'adi, Cairo) 42830, fragment of right mandibular ramus with MI-,, lower parts of crowns of P, and P4 (Figs 1,2). Locality: Fossil vertebrate quarry M, 249-m level of Jebel Qatrani Formation (Oligocene), Fayum Province, Egypt. Older than 31.0* 1.0 ~ ~ r ~ .  Diagnosis: Only known species: same as for genus. Measure- ments (mm) are: P4-M, (in series trigonids overlap talonids), 8.70; P4 length, 1.90; P, width, 1.60; M I  length, 2.45; M I  trigonid width, 2.00; M I  talonid width, 2.10; M, length, 2.30; M, length, 2.20; M, trigonid width, 1.80; M3 talonid width, 2.65; depth of horizontal ramus beneath anterior root of M, (lingual side), 3.25. Description: CGM 42830 is a right lower jaw fragment preserv- ing parts of P,-M, (Figs 1,2). The top of the crown of P, and most of P, are missing, as is much of the labial margin of M,. In addition, the protoconid of M I  and the metaconids of M I  and M, are broken. Anterior to P,, part of the distal border of an alveolus is preserved. The lower jaw is slender and shallow and maintains a fairly even depth of 3.25 mm beneath MI_,, shallowing to about 2.90 mm beneath P,. A tiny mental foramen is present about 1.20 mm above the inferior border of the jaw and slightly anterior to  the anterior root of P4. P,, are two-rooted teeth, P, being the smaller. Both teeth seem to have been essentially unicuspid. A small cristid connects the base of the P4 protoconid with the tiny hypoconulid on the posterior margin of the tooth. A well-developed labial cingulid becomes confluent posteriorly with this raised distal heel. In area and length of the molar crowns. M I  > M2> M,. The molars are simple tribosphenic teeth, each with a large, shelf-like paraconid separated from the metaconid and protoconid by a Fig. 2 Labial ( a ) ,  lingual ( b )  and occlusal ( d )  aspects of CGM 42830, holotype of Afrotarsius charrathi, and occlusal aspect ( c )  of FMNH 57281, Tarsius syrichta: c and d are stereo photographs. deep, curved, posteriorly convex sulcus. On M I  ., the paraconids are lingual to  the midline mesiodistal axis of the crown and project mesially, giving the trigonid an almost equilateral triangular shape in occlusal view. On M, the paraconid is more lingual in position and is slightly closer to the metaconid than on M I  or M,. The Mi., talonids are broad, deeply basined, bounded by hypoconids and entoconids of approximately equal size, and closed posteriorly by small but distinct hypoconulids. The entoconids are located on the distal border of the talonids, with the result that the talonid basins are long mediodistally. The high wall connecting the entoconids with the bases of the metaconids has an even crest, causing the talonid notch to be indistinct. M3 has a somewhat narrower talonid than M,, caused by the sharp posterolabial inflection of the entocristid, and possesses only two talonid cusps, a large hypoconid at the posterolabial margin of the crown, and a second cusp (hypoconulid or entoconid) at the centre of the posterior margin of the crown. A high oblique wall connects the hypoconulid with the base of the metaconid. As on MI.,, there is no distinct talonid notch. The M3 post-hypocristid reaches distally into a sharp notch at the base of the hypoconulid. The MI- ,  hypoflexids are shallow, the cristids obliquae reach- ing the bases of the trigonids slightly lingual to the protoconid. MI  and M3 have strong labial cingulids that cross the hypoflexid and merge with strong precingulids and weaker post-cingulids (this part of the crown is missing on M,). Afrotarsius chatrathi shows a mosaic of dental similarities to the late Eocene microchoerine Pseudoloris and to living South- East Asian Tarsius. Traditionally, Tarsius has been considered to be a living remnant of some early lineage of omomyid pri- mates, which were diverse and abundant during the Eocene in North America and Europe. More recently, several authors have suggested that Tarsius has a closer phyletic relationship with living and fossil higher primates than with o m ~ r n y i d s ~ ~ ' ~ " .  Non- etheless, the morphology of the teeth of Afrotarsius is clearly closest to that of living Tarsius and, among fossil forms, the Omomyidae. We therefore believe, in the absence of other evidence, that the affinities of Afrotarsius lie with these animals. Development of a linguolabially broad and shelf-like molar paraconid separated from the other cusps of the trigonid by a deep valley is a feature shared among Tarsius, Afrotarsius and Pseudoloris, although the more lingual placement of a relatively large paraconid in Afrotarsius is more reminiscent of the condi- tion in Tarsius than of that in Pseudoloris. Also shared is the distinctive posterolabial inflection of the M3 entocristid, an NATURE VOL. 313 7 FEBRUARY 1985 LETTERS TO NATURE 477 unusual feature that seems to link Afrotarsius and Tarsius to  the exclusion of other primate species. The presence of a tall, wall-like entocristid with an indistinct talonid notch, the direct opposition of the M,  metaconid and protoconid, and the development of tall hypoconids (not relatively short as in Pseudoloris) are additional features linking Afrotarsius more closely to Tarsius than to Pseudoloris. Thus, the combination of these and the other diagnostic features demonstrate that Afrotar- sius is closer in its dental morphology to Tarsius than to the Omomyidae, but within that family, Afrotarsius most closely resembles P.~eudoloris. Unfortunately, canines and incisors, which most clearly dis- tinguish microchoerines and Tarsius, are unknown for Afrotar- sius. Microchoerines, like other omomyids, tend to have a rela- tively large front tooth in the lower jaw. Of the two teeth immediately posterior to the front tooth, at least one is also relatively large. The anterior three teeth in the lower jaw of Tarsius, on the other hand, consist of a very large tooth flanked both anteriorly and posteriorly by much smaller teeth. The divergent structure and placement of the paraconid serve to  distinguish the molars of representatives of the omomyid sub-families Omomyinae, Anaptomorphinae and Micro- ~ h o e r i n a e l , ' ~ - ' ~ .  We believe that the paraconid condition in Afrotarsius is most similar to that of Tarsius and that in both it is different from that of omomyids. Because only one (if any) of the four basic types of paraconid development can be  primi- tive for primates of modern aspect, we feel that the paraconid condition in Afrotarsius is probably the most useful morphologi- $a1 guide to its relative kinship to  other primates. Concerning the palaeobiogeography of Tarsiiformes, rela- tively little more can be adduced from the discovery of a tarsier- like primate in Egypt. Given the Oligocene palaeogeography of Africa, Europe or  Asia are the obvious contenders for the ge~graphical 'or i~in of Afrotarsius and/or its ancestors. Either solution i m ~ l i e s  the Dresence on one of these continents of an unknown stock of' Tarsius-like ProSimii. Of these two possibilities, an Asian origin is perhaps the more likely, though supported only by circumstantial evidence: ( I )  there are no known suitable morphological candidates for the ancestry of Afrotarsius in the relatively well-sampled fossil record of the Euramerican Eocene Omomyidae; (2) the dentition of Afrotar- sius is structurally most similar to that of living South-East Asian Tarsius; and (3) at least some floral16 and faunalI7 ele- ments of the Egyptian Oligocene might have been more closely linked to those of various parts of Eocene and present-day South-East Asia than they are to floras and faunas of the early Tertiary of Europe. If Afrotarsius or its ancestors immigrated to  Africa from either Europe or  Asia, this dispersal is most likely to have taken place during the late Eocene-early Oligocene Tethyan regression, an event that facilitated the entry of mar- supials into Africa from ~ u r o p e ' ~ .  A last possibility is that Afrotarsius originated in Africa from an otherwise unknown (possibly omomyid) prosimian stock. By this viewpoint, Tarsius- like primates were deployed from Africa to Asia some time in the Tertiary. However, it is impossible at  present to  distinguish between these possibilities. We thank J. G. Fleagle, R. F. Kay, D. W. Krause, P. D. Gingerich, and F. C. Whitmore for review of the manuscript, B. Issawi and M. Askalany for scientific and logistic assistance in Egypt, and A. H. Coleman for photography. J. G. Fleagle mounted Fig. 2. We gratefully acknowledge support through NSF grant BNS-82-09937 to E.L.S., and grant BNS-1961A to J. G. Fleagle. Received 25 Ju ly ,  accepted 25 October 1984 I .  Simons. E. L. Prtmarr Evolurron: on Introduction roMan'sPlace In Nature. 1-322 (Macmillan, 10. MacPhee, R. D. E. & Cartmill. M. in Comparative Primate Biology Vol. I (ed. Swindler, D.) (Liss, New York, in the press). 11. Canmill, M. & Kay, R. F. Recent Ado. Primal. 3, 205-213 (1978). 12. Cartmill, M. in Evolutionary Biology of New World Monkeys and Continental Drift (eds Ciochon, R. L. & Chiarelli, B.) 243-274 (Plenum, New York, 1980). 13. Gazin, C. L. Smirhson misc. Callns 136, 1-1 12 (1958). 14. Bown, T. M. Folia primatol. 25. 62-72 (1976). 15. Bown, T. M. Wyoming geol. Sum. Mem 2, 1 - 15 1 ( 1979). 16. Bown, T. M. er at. I. hum. Evol. 11, 603-632 (1982). 17. Savage, D. E. & Russell, D. E. Mammalian Palaeofaunas of the World, 1.432 (Addison- Wesley, London, 1983). 18. Bown, T. M. & Simons, E. L. Nature 308,447.449 (1984). New York, 1972). 2. HoRatettrr, R. J. hum. Euol 3, 327-350 (1974). 3. Szalay, F. S. Bull Am. Mus. nar. Hist. 156, 157-450 (1976). 4. Gingerich, P. D J .  hum. Evol. 10, 345-374 (1980). 5. Dashzeveg, D. 8c McKenna, M. C. Acta palaeonr, pol. 22, 119-137 (1977). 6. Russell, D. t. & Gingerich, P. D. C r hebd. Sianc. Acad. Sci., Paris 291,621-624 (1980). 7. Simons. E. I.. Bull. Br M u s  ( n o t  Hist.) Geol. 5.45-69 (1961). 8. Schrnid. P. F~tlru prirnatol 40, 1-10 (1983)- 9. Fleagle, 1. G., Bown, T. M., Obradovlch, J. D. & Simons, E. L. Proc. loth Congr. inl. Prirnarol Sor (Cambridge University Press, in the press). 

A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from Africa

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
USGS Staff -- Published Research US Geological Survey 
1985 
A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from 
Africa 
Elwyn L. Simons 
Duke University 
Thomas M. Bown 
US Geological Survey 
Follow this and additional works at: https://digitalcommons.unl.edu/usgsstaffpub 
 Part of the Earth Sciences Commons 
Simons, Elwyn L. and Bown, Thomas M., "A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from 
Africa" (1985). USGS Staff -- Published Research. 205. 
https://digitalcommons.unl.edu/usgsstaffpub/205 
This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of 
Nebraska - Lincoln. It has been accepted for inclusion in USGS Staff -- Published Research by an authorized 
administrator of DigitalCommons@University of Nebraska - Lincoln. 
NATURE VOL. 313 7 FEBRUARY 1985 
- LETTERS TO NATURE- -- 47s -- . 
I nls artlcle IS a U S government work, and IS not subject to copyr~ght In the Unlted States 
A frotarsius chatrathi, first tarsiiform 
primate (? Tarsiidae) from Africa 
Duke University Primate Center, Durham. 
North Carolina 27705, USA 
Thomas M. Bown 
US Geological Survey, Denver, Colorado 80225, USA 
Tarsiiform primates have long been regarded as  a Laurasian group, 
with an extensive fossil record in the Eocene of North America 
and EuropeI4 and two important but less well-koown records from 
~ s i a ' . ~ .  The only living genus is Tanius (Tarsiidae), whereas all 
of the fossil tarsier-like primates are usually placed in the extinct 
family Omomyidae3. We now report the discovery of Afrotanius 
chatrathi from early Oligocene rocks of Fayum Province, Egypt. 
This is the first known tarsiifom primate from Africa. Compared 
with fossil primates, the molar tooth morphology of this diminutive 
prosimian is most similar to that of the European Eocene micro- 
choerine Pseudoloris; however, the closest similarity is to the 
476 LElTRS TO NATURE NATURE VOL. 313 7 FEBRUARY 1985 
molars of Tanius. Because the phylogenetic relationship among 
living Tarsius and the omomvids remain unclear7s and because 
of the fragmentary nature of {he only known specimen of this new 
primate, allocation of Afrotarsius to either Omomyidae or Tar- 
siidae is necessarily provisional. As we believe that its molar teeth 
are more like those of Tarsius than of any omomyids (including 
Pseudoloris), we tentatively assign the new genus to the extant 
family Tarsiidae as its only known fossil representative. Recovery 
of a Tarsius-like primate from Africa suggests that it or its 
ancestors might bave been immigrants from Europe, may have 
been derived from an unknown Asian stock related to the ancestry 
of Tanius, or may have originated in Africa. 
Order Primates 
Suborder Prosimii 
Infraorder Tarsiiformes 
Family Tarsiidae? 
Afrotarsius, gen. nov. 
Type species: Afrotarsius chatrathi, sp. nov. 
Diagmis: Differs from Tarsius in having a more posteriorly 
placed entoconid and thereby relatively longer distance between 
the Mi-, entoconid and metaconid; in having a relatively larger 
and slightly more labial M2 paraconid; in lacking a distinct 
entoconid and in having a smaller, less posteriorly extended 
posterior cusp on M,; and in having M3 with a shorter talonid 
and a relatively smaller crown with respect to M,. The specimen 
differs from all anaptomorphine and omomyine omomyids in 
the combination of labiolingually broad and shelf-like molar 
paraconids separated from metaconids and protoconids by a 
deep notch, and from all omomyids in having a raised, wall-like 
ridge between the entoconid and metaconid (both features as 
in Tarsius). It differs from all omomyids (except possibly Hemi- 
acodon and Macrotarsius) in having Mi  metaconid tingually 
opposite to  protoconid, not placed more posteriorly, and in 
having a smooth posterior wall on the MI  trigonid. It differs 
from all omomyids and Tarsius in having an indistinct talonid 
notch on molars and in having M I  > M, > M3. 
Afrotarsius chatrathi, sp. nov. 
Etymology: For Prithijit S. Chatrath, collector of the type and 
only known specimen. 
Holotype: CGM (Cairo Geological Museum. Ma'adi, Cairo) 
42830, fragment of right mandibular ramus with MI-,, lower 
parts of crowns of P, and P4 (Figs 1,2). 
Locality: Fossil vertebrate quarry M, 249-m level of Jebel 
Qatrani Formation (Oligocene), Fayum Province, Egypt. Older 
than 31.0* 1.0 ~ ~ r ~ .  
Diagnosis: Only known species: same as for genus. Measure- 
ments (mm) are: P4-M, (in series trigonids overlap talonids), 
8.70; P4 length, 1.90; P, width, 1.60; M I  length, 2.45; M I  trigonid 
width, 2.00; M I  talonid width, 2.10; M, length, 2.30; M, length, 
2.20; M, trigonid width, 1.80; M3 talonid width, 2.65; depth of 
horizontal ramus beneath anterior root of M, (lingual side), 3.25. 
Description: CGM 42830 is a right lower jaw fragment preserv- 
ing parts of P,-M, (Figs 1,2). The top of the crown of P, and 
most of P, are missing, as is much of the labial margin of M,. 
In addition, the protoconid of M I  and the metaconids of M I  
and M, are broken. Anterior to P,, part of the distal border of 
an alveolus is preserved. The lower jaw is slender and shallow 
and maintains a fairly even depth of 3.25 mm beneath MI_,, 
shallowing to about 2.90 mm beneath P,. A tiny mental foramen 
is present about 1.20 mm above the inferior border of the jaw 
and slightly anterior to  the anterior root of P4. 
P,, are two-rooted teeth, P, being the smaller. Both teeth 
seem to have been essentially unicuspid. A small cristid connects 
the base of the P4 protoconid with the tiny hypoconulid on the 
posterior margin of the tooth. A well-developed labial cingulid 
becomes confluent posteriorly with this raised distal heel. 
In area and length of the molar crowns. M I  > M2> M,. The 
molars are simple tribosphenic teeth, each with a large, shelf-like 
paraconid separated from the metaconid and protoconid by a 
Fig. 2 Labial ( a ) ,  lingual ( b )  and occlusal ( d )  aspects of CGM 
42830, holotype of Afrotarsius charrathi, and occlusal aspect ( c )  
of FMNH 57281, Tarsius syrichta: c and d are stereo photographs. 
deep, curved, posteriorly convex sulcus. On M I  ., the paraconids 
are lingual to  the midline mesiodistal axis of the crown and 
project mesially, giving the trigonid an almost equilateral 
triangular shape in occlusal view. On M, the paraconid is more 
lingual in position and is slightly closer to the metaconid than 
on M I  or M,. The Mi., talonids are broad, deeply basined, 
bounded by hypoconids and entoconids of approximately equal 
size, and closed posteriorly by small but distinct hypoconulids. 
The entoconids are located on the distal border of the talonids, 
with the result that the talonid basins are long mediodistally. 
The high wall connecting the entoconids with the bases of the 
metaconids has an even crest, causing the talonid notch to be 
indistinct. 
M3 has a somewhat narrower talonid than M,, caused by the 
sharp posterolabial inflection of the entocristid, and possesses 
only two talonid cusps, a large hypoconid at the posterolabial 
margin of the crown, and a second cusp (hypoconulid or 
entoconid) at the centre of the posterior margin of the crown. 
A high oblique wall connects the hypoconulid with the base of 
the metaconid. As on MI.,, there is no distinct talonid notch. 
The M3 post-hypocristid reaches distally into a sharp notch at 
the base of the hypoconulid. 
The MI- ,  hypoflexids are shallow, the cristids obliquae reach- 
ing the bases of the trigonids slightly lingual to the protoconid. 
MI  and M3 have strong labial cingulids that cross the hypoflexid 
and merge with strong precingulids and weaker post-cingulids 
(this part of the crown is missing on M,). 
Afrotarsius chatrathi shows a mosaic of dental similarities to 
the late Eocene microchoerine Pseudoloris and to living South- 
East Asian Tarsius. Traditionally, Tarsius has been considered 
to be a living remnant of some early lineage of omomyid pri- 
mates, which were diverse and abundant during the Eocene in 
North America and Europe. More recently, several authors have 
suggested that Tarsius has a closer phyletic relationship with 
living and fossil higher primates than with o m ~ r n y i d s ~ ~ ' ~ " .  Non- 
etheless, the morphology of the teeth of Afrotarsius is clearly 
closest to that of living Tarsius and, among fossil forms, the 
Omomyidae. We therefore believe, in the absence of other 
evidence, that the affinities of Afrotarsius lie with these animals. 
Development of a linguolabially broad and shelf-like molar 
paraconid separated from the other cusps of the trigonid by a 
deep valley is a feature shared among Tarsius, Afrotarsius and 
Pseudoloris, although the more lingual placement of a relatively 
large paraconid in Afrotarsius is more reminiscent of the condi- 
tion in Tarsius than of that in Pseudoloris. Also shared is the 
distinctive posterolabial inflection of the M3 entocristid, an 
NATURE VOL. 313 7 FEBRUARY 1985 LETTERS TO NATURE 477 
unusual feature that seems to link Afrotarsius and Tarsius to  
the exclusion of other primate species. The presence of a tall, 
wall-like entocristid with an indistinct talonid notch, the direct 
opposition of the M,  metaconid and protoconid, and the 
development of tall hypoconids (not relatively short as in 
Pseudoloris) are additional features linking Afrotarsius more 
closely to Tarsius than to Pseudoloris. Thus, the combination of 
these and the other diagnostic features demonstrate that Afrotar- 
sius is closer in its dental morphology to Tarsius than to the 
Omomyidae, but within that family, Afrotarsius most closely 
resembles P.~eudoloris. 
Unfortunately, canines and incisors, which most clearly dis- 
tinguish microchoerines and Tarsius, are unknown for Afrotar- 
sius. Microchoerines, like other omomyids, tend to have a rela- 
tively large front tooth in the lower jaw. Of the two teeth 
immediately posterior to the front tooth, at least one is also 
relatively large. The anterior three teeth in the lower jaw of 
Tarsius, on the other hand, consist of a very large tooth flanked 
both anteriorly and posteriorly by much smaller teeth. The 
divergent structure and placement of the paraconid serve to  
distinguish the molars of representatives of the omomyid 
sub-families Omomyinae, Anaptomorphinae and Micro- 
~ h o e r i n a e l , ' ~ - ' ~ .  We believe that the paraconid condition in 
Afrotarsius is most similar to that of Tarsius and that in both 
it is different from that of omomyids. Because only one (if any) 
of the four basic types of paraconid development can be  primi- 
tive for primates of modern aspect, we feel that the paraconid 
condition in Afrotarsius is probably the most useful morphologi- 
$a1 guide to its relative kinship to  other primates. 
Concerning the palaeobiogeography of Tarsiiformes, rela- 
tively little more can be adduced from the discovery of a tarsier- 
like primate in Egypt. Given the Oligocene palaeogeography of 
Africa, Europe or  Asia are the obvious contenders for the 
ge~graphical 'or i~in of Afrotarsius and/or its ancestors. Either 
solution i m ~ l i e s  the Dresence on one of these continents of an 
unknown stock of' Tarsius-like ProSimii. Of these two 
possibilities, an Asian origin is perhaps the more likely, though 
supported only by circumstantial evidence: ( I )  there are no 
known suitable morphological candidates for the ancestry of 
Afrotarsius in the relatively well-sampled fossil record of the 
Euramerican Eocene Omomyidae; (2) the dentition of Afrotar- 
sius is structurally most similar to that of living South-East 
Asian Tarsius; and (3) at least some floral16 and faunalI7 ele- 
ments of the Egyptian Oligocene might have been more closely 
linked to those of various parts of Eocene and present-day 
South-East Asia than they are to floras and faunas of the early 
Tertiary of Europe. If Afrotarsius or its ancestors immigrated 
to  Africa from either Europe or  Asia, this dispersal is most likely 
to have taken place during the late Eocene-early Oligocene 
Tethyan regression, an event that facilitated the entry of mar- 
supials into Africa from ~ u r o p e ' ~ .  A last possibility is that 
Afrotarsius originated in Africa from an otherwise unknown 
(possibly omomyid) prosimian stock. By this viewpoint, Tarsius- 
like primates were deployed from Africa to Asia some time in 
the Tertiary. However, it is impossible at  present to  distinguish 
between these possibilities. 
We thank J. G. Fleagle, R. F. Kay, D. W. Krause, P. D. 
Gingerich, and F. C. Whitmore for review of the manuscript, 
B. Issawi and M. Askalany for scientific and logistic assistance 
in Egypt, and A. H. Coleman for photography. J. G. Fleagle 
mounted Fig. 2. We gratefully acknowledge support through 
NSF grant BNS-82-09937 to E.L.S., and grant BNS-1961A to 
J. G. Fleagle. 
Received 25 Ju ly ,  accepted 25 October 1984 
I .  Simons. E. L. Prtmarr Evolurron: on Introduction roMan'sPlace In Nature. 1-322 (Macmillan, 
10. MacPhee, R. D. E. & Cartmill. M. in Comparative Primate Biology Vol. I (ed. Swindler, 
D.) (Liss, New York, in the press). 
11. Canmill, M. & Kay, R. F. Recent Ado. Primal. 3, 205-213 (1978). 
12. Cartmill, M. in Evolutionary Biology of New World Monkeys and Continental Drift (eds 
Ciochon, R. L. & Chiarelli, B.) 243-274 (Plenum, New York, 1980). 
13. Gazin, C. L. Smirhson misc. Callns 136, 1-1 12 (1958). 
14. Bown, T. M. Folia primatol. 25. 62-72 (1976). 
15. Bown, T. M. Wyoming geol. Sum. Mem 2, 1 - 15 1 ( 1979). 
16. Bown, T. M. er at. I. hum. Evol. 11, 603-632 (1982). 
17. Savage, D. E. & Russell, D. E. Mammalian Palaeofaunas of the World, 1.432 (Addison- 
Wesley, London, 1983). 
18. Bown, T. M. & Simons, E. L. Nature 308,447.449 (1984). 
New York, 1972). 
2. HoRatettrr, R. J. hum. Euol 3, 327-350 (1974). 
3. Szalay, F. S. Bull Am. Mus. nar. Hist. 156, 157-450 (1976). 
4. Gingerich, P. D J .  hum. Evol. 10, 345-374 (1980). 
5. Dashzeveg, D. 8c McKenna, M. C. Acta palaeonr, pol. 22, 119-137 (1977). 
6. Russell, D. t. & Gingerich, P. D. C r hebd. Sianc. Acad. Sci., Paris 291,621-624 (1980). 
7. Simons. E. I.. Bull. Br M u s  ( n o t  Hist.) Geol. 5.45-69 (1961). 
8. Schrnid. P. F~tlru prirnatol 40, 1-10 (1983)- 
9. Fleagle, 1. G., Bown, T. M., Obradovlch, J. D. & Simons, E. L. Proc. loth Congr. inl. 
Prirnarol Sor (Cambridge University Press, in the press). 


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A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from Africa

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