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Shenshou and Xianshou, new allotherian mammals from Jurassic of China



Ben Creisler
bcreisler@gmail.com

New online paper in Nature (supplementary material is free):

New taxa: Shenshou lui, Xianshou linglong and Xianshou songae

Shundong Bi, Yuanqing Wang, Jian Guan, Xia Sheng & Jin Meng (2014)
Three new Jurassic euharamiyidan species reinforce early divergence of mammals.
Nature (advance online publication)
doi:10.1038/nature13718
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13718.html


The phylogeny of Allotheria, including Multituberculata and
Haramiyida, remains unsolved and has generated contentious views on
the origin and earliest evolution of mammals. Here we report three new
species of a new clade, Euharamiyida, based on six well-preserved
fossils from the Jurassic period of China. These fossils reveal many
craniodental and postcranial features of euharamiyidans and clarify
several ambiguous structures that are currently the topic of debate.
Our phylogenetic analyses recognize Euharamiyida as the sister group
of Multituberculata, and place Allotheria within the Mammalia. The
phylogeny suggests that allotherian mammals evolved from a Late
Triassic (approximately 208 million years ago) Haramiyavia-like
ancestor and diversified into euharamiyidans and multituberculates
with a cosmopolitan distribution, implying homologous acquisition of
many craniodental and postcranial features in the two groups. Our
findings also favour a Late Triassic origin of mammals in Laurasia and
two independent detachment events of the middle ear bones during
mammalian evolution.