Sunday, May 8, 2016

[PaleoMammalogy • 2016] Oligocene Primates from China Reveal Divergence between African and Asian Primate Evolution



The Eocene-Oligocene transition (EOT) functioned as a critical filtering episode during the evolutionary history of primates. Comparing the composition of the early Oligocene primate faunas from Asia reveals that surviving this Eocene-Oligocene evolutionary filter entailed a high degree of taxonomic and ecological selectivity: later Eocene primate assemblages tend to be dominated, both in terms of taxonomic richness and numerical abundance, by stem anthropoids, whereas the Oligocene primate tend to be dominated by lemur-like strepsirrhine primates. A similar comparison of the late Eocene-early Oligocene primates from Afro-Arabia shows a very different pattern of selectivity in response to the EOT: very few strepsirrhine primates survived the EOT, whereas anthropoids diversified both taxonomically and ecologically. The divergent responses shown by Afro-Arabian and Asian primates across the EOT evolutionary filter constrained the subsequent course of primate macroevolutionary pattern across the Old World. Africa became the geographic nexus of anthropoid evolution, whereas Asia shows a strong break between Paleogene and Neogene anthropoid assemblages.

 Abstract

Profound environmental and faunal changes are associated with climatic deterioration during the Eocene-Oligocene transition (EOT) roughly 34 million years ago. Reconstructing how Asian primates responded to the EOT has been hindered by a sparse record of Oligocene primates on that continent. Here, we report the discovery of a diverse primate fauna from the early Oligocene of southern China. In marked contrast to Afro-Arabian Oligocene primate faunas, this Asian fauna is dominated by strepsirhines. There appears to be a strong break between Paleogene and Neogene Asian anthropoid assemblages. Asian and Afro-Arabian primate faunas responded differently to EOT climatic deterioration, indicating that the EOT functioned as a critical evolutionary filter constraining the subsequent course of primate evolution across the Old World.


The Eocene-Oligocene transition (EOT) functioned as a critical filtering episode during the evolutionary history of primates. Comparing the composition of the early Oligocene primate faunas from Asia reveals that surviving this Eocene-Oligocene evolutionary filter entailed a high degree of taxonomic and ecological selectivity: later Eocene primate assemblages tend to be dominated, both in terms of taxonomic richness and numerical abundance, by stem anthropoids, whereas the Oligocene primate tend to be dominated by lemur-like strepsirrhine primates. A similar comparison of the late Eocene-early Oligocene primates from Afro-Arabia shows a very different pattern of selectivity in response to the EOT: very few strepsirrhine primates survived the EOT, whereas anthropoids diversified both taxonomically and ecologically. The divergent responses shown by Afro-Arabian and Asian primates across the EOT evolutionary filter constrained the subsequent course of primate macroevolutionary pattern across the Old World. Africa became the geographic nexus of anthropoid evolution, whereas Asia shows a strong break between Paleogene and Neogene anthropoid assemblages. 

Primates Linnaeus, 1758;
Strepsirhini Geoffroy,1812;
Adapiformes Hoffstetter, 1977;
• Sivaladapidae Thomas and Verma, 1979;

Yunnanadapis gen. nov.

Type species: Yunnanadapis folivorus sp. nov.
Included species: The type species and Yunnanadapis imperator sp. nov.

Etymology: Generic name recognizes the geographic provenance of this taxon and its adapiform affinities.

Laomaki yunnanensis gen. et sp. nov.

 Etymology: Generic name derives from the Mandarin“lao”(old) and the Malagasy“maky”(lemur). Trivial name reflects the geographic provenance of this species.

• Ekgmowechashalidae Szalay, 1976;
Gatanthropus micros gen. et sp. nov. 

Etymology: In allusionto the ekgmowechashalid affinities of this taxon,its generic name derives from the Greek“gata”(cat) and“anthropus”(man), and its trivial name derives from the Greek “micros”(small). Ekgmowechashala signifies“little cat man”in the Lakotalanguage, which lacks a term for non-human primates.

Haplorhini Pocock, 1918;
Tarsiiformes Gregory,1915;
• Tarsiidae Gray, 1825;

Oligotarsius rarus gen. et sp. nov.

Etymology: Generic name reflects the age of this taxon. Trivial name reflects the sparse documentation of Tarsiidae in the fossil record generally, as well as the meager representation of this species in the Caijiachong early Oligocene fauna.

  Anthropoidea Mivart, 1864;
• Eosimiidae Beard et al., 1994;
Bahinia Jaeger et al., 1999;
Bahinia banyueae sp. nov.

Etymology: Trivial name honors the pioneering work on the Caijiachong mammal faunas of Yunnan Province made by our friend and colleague Banyue Wang.


Xijun Ni, Qiang Li, Lüzhou Li and K. Christopher Beard. 2016. Oligocene Primates from China Reveal Divergence between African and Asian Primate Evolution. Science. 352(6286); 673-677. DOI:  10.1126/science.aaf2107

Could these new fossils solve 'paradox' of primate evolution? http://fw.to/ESIEKUg
Six new fossil species form 'snapshot' of primates stressed by ancient climate change http://phy.so/381644194 via @physorg_com
 twitter.com/ScienceMagazine/status/730794710730706945

Climate filters dominant species
The transition between the Eocene and Oligocene periods was marked by distinct cooling. Because primate species are particularly susceptible to cold, this change in climate drove a retraction of primates globally. After this transition, anthropoid primates were dominant in Afro-Arabian regions, but little has been known about primate reestablishment in Asia. Ni et al. describe 10 previously unknown primates found in Yunnan Province in China that show that primates took a different path in Asia. Instead of anthropoids, strepsirrhine (lemur-like) primates were dominant. It is still unknown whether this difference was due to the environment or chance.

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