New data on the crown proteid Bishara backa from the Upper Cretaceous (Bostobe Formation) of Kazakhstan: implications for early evolution and palaeobiogeography of proteidae

Skutschas P.P. Malakhov D.V. Parakhin I.A. Kolchanov V.V.
2025 Taylor and Francis Ltd.

Historical Biology
2025 #37 Issue 7 1706 - 1714 pp.

We provide a detailed redescription of all available material for the geologically oldest proteid salamander Bishara backa from the Upper Cretaceous (Santonian–lower Campanian) Bostobe Formation in Kazakhstan, consisting an atlantal centrum (neotype of Bishara backa) and a trunk vertebra. Bishara backa is characterised by the following combination of characters: large, dorsoventrally compressed and almost flat anterior cotyles of atlas enclosing an angle about 230°; anterior cotylar surfaces are continuous medially across lateral surfaces of small, dorsally placed intercotylar tubercle; ventrolateral ridges are alar-like; atlantal transverse processes are bicipitate; oblique anterior alar processes and lateral fossae on atlas present; transverse processes on trunk vertebra are bicipitate and divergent; alar processes on trunk vertebra are prominent; anterodorsal ridge on trunk vertebra is present; neural arch of trunk vertebra with high neural spine and grooves on its posterior face; two large subcentral foramina on ventral surface of the centrum. Our phylogenetic analyses finds Bishara backa as a crown proteid and a basal member of Eurasian clade of crown proteids (Bishara+Proteus+Mioproteus). We propose a model of proteid evolution that includes three main episodes of radiations with the last two taking place during the Late Cretaceous and the Palaeocene–Eocene thermal maximum.

Asia , biogeography , Cretaceous , crown-group , Proteidae

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Vertebrate Zoology Department, Saint Petersburg State University, St. Petersburg, Russian Federation
GIS and Remote Sensing Department, Institute of Zoology, Almaty, Kazakhstan

Vertebrate Zoology Department
GIS and Remote Sensing Department

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