SilesianTriassic

Sauropterygia indet. (cf. Nothosaurus)

Middle Triassic, Lower Muschelkalk (Anisian), Gogolin Beds

Upper Silesia, Poland

Probably isolated metacarpal or metatarsal bone of an unidentified Sauropterygia (most likely a medium-sized Nothosaurus). Due to the visible slight asymmetry, I think it is most likely one of the outer metacarpals or metatarsals – I or V.

The bone is flattened in cross-section and has a simplified structure. The articular surfaces of the heads are rather flat, slightly convex. The bone is 30mm long at its longest point, ~8mm wide, and 6mm at its narrowest. The wider head is slightly oblique. Narrow head is 7mm.

On the bone’s surface, near the heads, a delicate, radial ornamentation towards the heads is visible.

The bone is certainly not one of the largest long bones. Personally, I also rule out a phalanx; it should be shorter and more hourglass-shaped. The simple, flattened shape is consistent with Sauropterygia, but the bone seems too large for a member of the Pachypleurosauridae, more likely a medium-sized Eosauropterygia.

References:

Williston, S. W. (1925). The Osteology of the Reptiles. Cambridge: Harvard University Press.

Shang, Qinghua & Li, Chun & WANG, Wei & Palasiatica, Vertebrata. (2022). Nothosaurus luopingensis sp. nov. (Sauropterygia) from the Anisian, Middle Triassic of Luoping, Yunnan Province, China. 60.