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Niassodon, new dicynodont from Upper Permian of Mozambique



From: Ben Creisler
bcreislerf@gmail.com

New in PLoS ONE:


Ricardo Araújo, Luís C. Júnior, Kenneth D. Angielczyk, Gabriel G.
Martins, Rui M. S. Martins, Claudine Chaouiya, Felix Beckmann &
Fabian Wilde (2013)
Bringing Dicynodonts Back to Life: Paleobiology and Anatomy of a New
Emydopoid Genus from the Upper Permian of Mozambique.
PLoS ONE 8(12): e80974.
doi:10.1371/journal.pone.0080974
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0080974;jsessionid=5572C467F7093D87754754DAAB247FE7

Dicynodontia represent the most diverse tetrapod group during the Late
Permian. They survived the Permo-Triassic extinction and are central
to understanding Permo-Triassic terrestrial ecosystems. Although
extensively studied, several aspects of dicynodont paleobiology such
as, neuroanatomy, inner ear morphology and internal cranial anatomy
remain obscure. Here we describe a new dicynodont (Therapsida,
Anomodontia) from northern Mozambique: Niassodon mfumukasi gen. et sp.
nov. The holotype ML1620 was collected from the Late Permian K5
formation, Metangula Graben, Niassa Province northern Mozambique, an
almost completely unexplored basin and country for vertebrate
paleontology. Synchrotron radiation based micro-computed tomography
(SRµCT), combined with a phylogenetic analysis, demonstrates a set of
characters shared with Emydopoidea. All individual bones were
digitally segmented allowing a 3D visualization of each element. In
addition, we reconstructed the osseous labyrinth, endocast, cranial
nerves and vasculature. The brain is narrow and the cerebellum is
broader than the forebrain, resembling the conservative,
“reptilian-grade” morphology of other non-mammalian therapsids, but
the enlarged paraflocculi occupy the same relative volume as in birds.
The orientation of the horizontal semicircular canals indicates a
slightly more dorsally tilted head posture than previously assumed in
other dicynodonts. In addition, synchrotron data shows a secondary
center of ossification in the femur. Thus ML1620 represents, to our
knowledge, the oldest fossil evidence of a secondary center of
ossification, pushing back the evolutionary origins of this feature.
The fact that the specimen represents a new species indicates that the
Late Permian tetrapod fauna of east Africa is still incompletely
known.