Um fóssil de primata com afinidades incertas do início do Eoceno inferior do Egito

terça-feira, maio 11, 2010

A fossil primate of uncertain affinities from the earliest late Eocene of Egypt

Erik R. Seiffert a,1, Elwyn L. Simons b,1, Doug M. Boyer c, Jonathan M. G. Perry d, Timothy M. Ryan e, and Hesham M. Sallam f

-Author Affiliations

aDepartment of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-8081;
bDivision of Fossil Primates, Duke Lemur Center, Durham, NC 27705;
cDepartment of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245;
dDepartment of Anatomy, Midwestern University, Downers Grove, IL 60515;
eDepartment of Anthropology, Pennsylvania State University, University Park, PA 16802; and
fDepartment of Earth Sciences, University of Oxford, Oxford OX1 3PR, United Kingdom

Contributed by Elwyn L. Simons, February 18, 2010 (sent for review January 5, 2010)

Abstract

Paleontological work carried out over the last 3 decades has established that three major primate groups were present in the Eocene of Africa—anthropoids, adapiforms, and advanced strepsirrhines. Here we describe isolated teeth of a previously undocumented primate from the earliest late Eocene (≈37 Ma) of northern Egypt, Nosmips aenigmaticus, whose phylogenetic placement within Primates is unclear. Nosmips is smaller than the sympatric adapiform Afradapisbut is considerably larger than other primate taxa known from the same paleocommunity. The species bears an odd mosaic of dental features, combining enlarged, elongate, and molariform premolars with simple upper molars that lack hypocones. Phylogenetic analysis across a series of different assumption sets variously places Nosmips as a stem anthropoid, a nonadapiform stem strepsirrhine, or even among adapiforms. This phylogenetic instability suggests to us that Nosmips likely represents a highly specialized member of a previously undocumented, and presumably quite ancient, endemic African primate lineage, the subordinal affinities of which have been obscured by its striking dental autapomorphies. Discriminant functions based on measurements of lower molar size and topography reliably classify extant prosimian primates into their correct dietary groups and identify Nosmips and Afradapis as omnivores and folivores, respectively. Although Nosmips currently defies classification, this strange and unexpected fossil primate nevertheless provides additional evidence for high primate diversity in northern Africa ≈37 million years ago and further underscores the fact that our understanding of early primate evolution on that continent remains highly incomplete.

Africa    Anthropoidea   Fayum   phylogeny   Strepsirrhini

Footnotes

1To whom correspondence may be addressed. E-mail:erik.seiffert@stonybrook.edu or esimons@duke.edu.
Author contributions: E.R.S. and D.M.B. designed research; E.R.S., E.L.S., D.M.B., J.M.G.P., T.M.R., and H.M.S. performed research; E.R.S., D.M.B., and J.M.G.P. analyzed data; and E.R.S., D.M.B., and J.M.G.P. wrote the paper.

The authors declare no conflict of interest.

This article contains supporting information online at www.pnas.org/cgi/content/full/1001393107/DCSupplemental.

1To whom correspondence may be addressed. E-mail:erik.seiffert@stonybrook.edu or esimons@duke.edu.

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