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Astragalar morphology of Afradapis, a large adapiform primate from the earliest late Eocene of Egypt.

Publication ,  Journal Article
Boyer, DM; Seiffert, ER; Simons, EL
Published in: American journal of physical anthropology
November 2010

The ∼37 million-year-old Birket Qarun Locality 2 (BQ-2), in the Birket Qarun Formation of Egypt's Fayum Depression, yields evidence for a diverse primate fauna, including the earliest known lorisiforms, parapithecoid anthropoids, and Afradapis longicristatus, a large folivorous adapiform. Phylogenetic analysis has placed Afradapis as a stem strepsirrhine within a clade of caenopithecine adapiforms, contradicting the recently popularized alternative hypothesis aligning adapiforms with haplorhines or anthropoids. We describe an astragalus from BQ-2 (DPC 21445C), attributable to Afradapis on the basis of size and relative abundance. The astragalus is remarkably similar to those of extant lorises, having a low body, no posterior shelf, a broad head and neck. It is like extant strepsirrhines more generally, in having a fibular facet that slopes gently away from the lateral tibial facet, and in having a groove for the tendon of flexor fibularis that is lateral to the tibial facet. Comparisons to a sample of euarchontan astragali show the new fossil to be most similar to those of adapines and lorisids. The astragali of other adapiforms are most similar to those of lemurs, but distinctly different from those of all anthropoids. Our measurements show that in extant strepsirrhines and adapiforms the fibular facet slopes away from the lateral tibial facet at a gradual angle (112-126°), in contrast to the anthropoid fibular facet, which forms a sharper angle (87-101°). Phylogenetic analyses incorporating new information from the astragalus continue to support strepsirrhine affinities for adapiforms under varying models of character evolution.

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Published In

American journal of physical anthropology

DOI

EISSN

1096-8644

ISSN

0002-9483

Publication Date

November 2010

Volume

143

Issue

3

Start / End Page

383 / 402

Related Subject Headings

  • X-Ray Microtomography
  • Talus
  • Statistics, Nonparametric
  • Primates
  • Phylogeny
  • Least-Squares Analysis
  • Fossils
  • Egypt
  • Anthropology
  • Animals
 

Citation

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ICMJE
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Boyer, D. M., Seiffert, E. R., & Simons, E. L. (2010). Astragalar morphology of Afradapis, a large adapiform primate from the earliest late Eocene of Egypt. American Journal of Physical Anthropology, 143(3), 383–402. https://doi.org/10.1002/ajpa.21328
Boyer, Doug M., Erik R. Seiffert, and Elwyn L. Simons. “Astragalar morphology of Afradapis, a large adapiform primate from the earliest late Eocene of Egypt.American Journal of Physical Anthropology 143, no. 3 (November 2010): 383–402. https://doi.org/10.1002/ajpa.21328.
Boyer DM, Seiffert ER, Simons EL. Astragalar morphology of Afradapis, a large adapiform primate from the earliest late Eocene of Egypt. American journal of physical anthropology. 2010 Nov;143(3):383–402.
Boyer, Doug M., et al. “Astragalar morphology of Afradapis, a large adapiform primate from the earliest late Eocene of Egypt.American Journal of Physical Anthropology, vol. 143, no. 3, Nov. 2010, pp. 383–402. Epmc, doi:10.1002/ajpa.21328.
Boyer DM, Seiffert ER, Simons EL. Astragalar morphology of Afradapis, a large adapiform primate from the earliest late Eocene of Egypt. American journal of physical anthropology. 2010 Nov;143(3):383–402.
Journal cover image

Published In

American journal of physical anthropology

DOI

EISSN

1096-8644

ISSN

0002-9483

Publication Date

November 2010

Volume

143

Issue

3

Start / End Page

383 / 402

Related Subject Headings

  • X-Ray Microtomography
  • Talus
  • Statistics, Nonparametric
  • Primates
  • Phylogeny
  • Least-Squares Analysis
  • Fossils
  • Egypt
  • Anthropology
  • Animals