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Alveusdectes, new diadectomorph from Upper Permian of China



Ben Creisler
bcreisler@gmail.com

A new paper:

Jun Liu & G. S. Bever (2015)
The last diadectomorph sheds light on Late Palaeozoic tetrapod biogeography.
Biology Letters (advance online publication)
DOI: 10.1098/rsbl.2015.0100 Published 6 May 2015
http://rsbl.royalsocietypublishing.org/content/11/5/20150100

Diadectomorpha is a clade of Late Palaeozoic vertebrates widely
recognized as the sister group of crown-group Amniota and the first
tetrapod lineage to evolve high-fibre herbivory. Despite their
evolutionary importance, diadectomorphs are restricted
stratigraphically and geographically, with all records being from the
Upper Carboniferous and Lower Permian of North America and Germany. We
describe a new diadectomorph, Alveusdectes fenestralis, based on a
partial skull from the Upper Permian of China. The new species
exhibits the derived mechanism for herbivory and is recovered
phylogenetically as a deeply nested diadectid. Approximately 16 Myr
younger than any other diadectomorph, Alveusdectes is the product of
at least a 46 Myr ghost lineage. How much of this time was probably
spent in Russia and/or central Asia will remain unclear until a
specimen is described that subdivides this cryptic history, but the
lineage assuredly crossed this region before entering the relatively
isolated continent of North China. The discovery of Alveusdectes
raises important questions regarding diadectomorph extinction dynamics
including what, if any, ecological factors limited the diversity of
this group in eastern Pangea. It also suggests that increased sampling
in Asia will likely significantly affect our views of clade and faunal
insularity leading up to the Permo-Triassic extinction.