The bony labyrinth of late Permian Biarmosuchia: palaeobiology and diversity in non-mammalian Therapsida

Benoit, Julien; Manger, Paul R; Fernandez, Vincent; Rubidge, Bruce S

The bony labyrinth of late Permian Biarmosuchia: palaeobiology and diversity in non-mammalian Therapsida

dc.contributor.author	Benoit, Julien
dc.contributor.author	Manger, Paul R
dc.contributor.author	Fernandez, Vincent
dc.contributor.author	Rubidge, Bruce S
dc.date.accessioned	2017-07-24T12:14:24Z
dc.date.available	2017-07-24T12:14:24Z
dc.date.issued	2017-07
dc.description.abstract	Biarmosuchia, as the basalmost group of Therapsida (the stem group of mammals), are important for understanding mammalian origins and evolution. Unlike other therapsid groups, the bony labyrinth of biarmosuchians has not yet been studied, despite insightful clues that bony labyrinth morphology can provide to address palaeobiology and phylogeny of extinct animals. Here, using CT scanning, surface reconstruction and a 3D geometric-morphometric protocol of 60 semi-landmarks on the bony labyrinth of 30 therapsids (including three Mammaliaformes), it is demonstrated that bony labyrinth morphology of biarmosuchians is very distinctive compared to that of other therapsids. Despite the primitive nature of their cranial morphology, biarmosuchians display highly derived traits in the structure of the bony labyrinth. The most noticeable are the presence of a long and slender canal linking the vestibule to the fenestra vestibuli, an enlarged and dorsally expanded anterior canal, and the absence of a secondary common crus (except for one specimen), which sets them apart from other non-mammalian therapsids. These characters provide additional support for the monophyly of Biarmosuchia, the most recently recognized major therapsid subclade. Although implications of the derived morphology of the biarmosuchian bony labyrinth are discussed, definitive interpretations are dependent on the discovery of well-preserved postcranial material. It nevertheless sheds light on a previously overlooked diversity of bony labyrinth morphology in non-mammalian therapsids.	en_ZA
dc.description.librarian	JNC	en_ZA
dc.description.sponsorship	The Palaeontological Scientific Trust (PAST) and its Scatterlings of Africa Programmes NRF South Africa DST-NRF Centre of Excellence in Palaeosciences	en_ZA
dc.identifier.issn	2410-4418
dc.identifier.uri	http://hdl.handle.net/10539/23023
dc.journal.title	Palaeontologia africana	en_ZA
dc.journal.volume	52	en_ZA
dc.language.iso	en	en_ZA
dc.rights	Copyright the authors	en_ZA
dc.subject	Biarmosuchia	en_ZA
dc.subject	Therapsida	en_ZA
dc.subject	bony labyrinth	en_ZA
dc.subject	inner-ear	en_ZA
dc.subject	geometric morphometrics	en_ZA
dc.title	The bony labyrinth of late Permian Biarmosuchia: palaeobiology and diversity in non-mammalian Therapsida	en_ZA
dc.type	Article	en_ZA