''Afradapis'' is a genus of

adapiform Adapiformes is a group of early primates. Adapiforms radiated throughout much of the northern continental mass (now Europe, Asia and North America), reaching as far south as northern Africa and tropical Asia. They existed from the Eocene to the M ...

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

that lived during the

Late Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "daw ...

.Seiffert, E. R., Boyer, D. M., Fleagle, J. G., Gunnell, G. F., Heesy, C. P., Perry, J. M. G., & Sallam, H. M. (2018). New adapiform primate fossils from the late Eocene of Egypt. Historical Biology, 30(1–2), 204–226. https://doi.org/10.1080/08912963.2017.1306522Seiffert, E. R., Perry, J. M. G., Simons, E. L., & Boyer, D. M. (2009). Convergent evolution of anthropoid-like adaptations in Eocene adapiform primates. Nature, 461(7267), 1118–1121. https://doi.org/10.1038/nature08429 The only known species, ''Afradapis longicristatus'', was discovered in the Birket Qarun Formation in northern Egypt in 2009. While its geographic distribution is confined to Afro-Arabia, ''Afradapis'' belongs to the predominantly European adapiform family Caenopithecidae. This taxonomic placement is supported by recent phylogenetic analyses that recover a close evolutionary relationship between ''Afradapis'' and adapiforms, including Darwinius.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 While adapiforms have been noted for their strepsirrhine-like morphology, no adapiform fossil possesses the unique anatomical traits (i.e., synapomorphies) to establish an ancestor-descent relationship between caenopithecids and living strepsirrhines (i.e., lemurs, lorises, and galagos). It ate leaves and moved around slowly like

loris Loris is the common name for the strepsirrhine mammals of the subfamily Lorinae (sometimes spelled Lorisinae) in the family Lorisidae. ''Loris'' is one genus in this subfamily and includes the slender lorises, ''Nycticebus'' is the genus contain ...

es.

Etymology

Afra- (Latin) means “Africa” while -adapis refers to Adapis, as described by Cuvier, 1821. Longi- (Latin) means “long” and -cristatus (Latin) means “crested”.

Taxonomy

Based on the combination of lemur-like dental and postcranial anatomy, ''Afradapis'' is recognized as an adapiform. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen representing ''Afradapis longicristatus'' (CGM 83690) consists of a partial left mandible that preserves P4–M3 and the masseteric fossa. ''Afradapis'' is characterized by a suite of adapiform and anthropoid-like dental features. Despite possessing multiple anthropoid traits, phylogenetic analyses have recovered ''Afradapis'' as a distant relative of anthropoids; thus, the anthropoid-like traits are the product convergent evolution. ''Afradapis'' belongs to the subfamily Caenopithecidae, which also includes Cernopithecus, Aframonius, and Masradapis. However, the exact relationships among these extinct taxa are still under debate. Despite similar naming, ''Afradapis'' is more closely related to Ceanopithecus than Aframonius, on account of the more derived 2.1.2.3 dental formula, which an anthropoid-like trait. These broader evolutionary relationships reveals an interesting biogepgrpahic history for caenopithecid adapiforms, as the timing and placement of Afrapids in northern Africa indicates at least one dispersal event from Europe to Africa across the Tethys Sea as early as 56 million years ago, at the end of the Paleocene.Beard, Christopher. "Adapiform". Encyclopedia Britannica, 2016, https://www.britannica.com/animal/adapiform. Accessed 27 April 2021.

Description

Estimates of adult weight for ''Afradapis'' range from 2.1kg to 3.3kg. These estimates have been derived from prosimian-specific regression questions, which calculate body mass based on the area of M1 area and length M2. Compared to other caenopithecids, ''Afradapis'' evolutionarily lost P2, resulting in a 2.1.2.3 lower dental formula. ''Afradapis'' possesses an

astragalus ''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to tempe ...

with a strongly sloping fibular facet that resembles those of extant lorises. This morphology has been attributed to slow-climbing arboreal locomotion seen in living lorises.Gingerich, P. D. (1980). Eocene Adapidae, paleobiogeography, and the origin of South American Platyrrhini. In Evolutionary biology of the New World monkeys and continental drift (pp. 123-138). Springer, Boston, MA. Afradapis also differs from other caenopithecid adapiforms in their dental anatomy in the following ways: possession of tall and trenchant upper and lower third premolars, a variably present mesoconid on lower molars (usually on M1), a lack of metastylids on M1-3, and large hypocones and prehypocristae present on all upper molars. The mandible of ''Afradapis'' differs from other caenopithecid adapiforms in having a deep yet short corpus, a well-developed masseteric fossa, a fused manibudlar symphysis, and a short condylar neck with a low condyle relative to the lower tooth row. Based on the known fossils of this taxon, there is no evidence of canine dimorphism in ''Afradapis'', which suggests that ''Afradapis'' was not sexually dimorphic like some North American adapiforms.Gingerich, P.D. (1995). Sexual dimorphism in earliest Eocene Cantius Torresi (Mammalia, Primates, Adapoidea). Contributions from the Museum of Paleontology University of Michigan, 29, 185-199. Afradpais is also characterized by elaborate shearing crests on its molars, which is indicative of a folivorous diet. Because ''Afradapis'' seemingly shares many traits with anthropoids, researchers initially considered it to possibly be an anthropoid during initial investigations. Nonetheless, these similarities appear to be cases of convergent evolution, confirmed by both phylogeny and niche modeling.

Paleoecology and geography

''Afradapis'' is considered to have existed throughout Afro-Arabia in the late Eocene after a dispersal from the Europe via the Tethys Sea. Collectively, its elaborate shearing crests, relatively large body size, and postcranial anatomy indicative of slow-climbing all strongly suggests that ''Afradapis'' was nearly exclusively folivorous. Given Kay’s Threshold, which posits that living primates over 500 grams tend to be folivores, the dietary behavior and body size estimates of Afradapis collectively support the reconstruction of Afradpis as relatively large bodied folivore. Niche modeling studies also reveal that ''Afradapis'' was most likely diurnal that probably competed for food resources with African anthropoids.

References

{{Taxonbar, from=Q19760265 Prehistoric strepsirrhines Prehistoric primate genera Monotypic prehistoric primate genera Eocene primates Eocene mammals of Africa Fossils of Egypt Fossil taxa described in 2009