SilesianTriassic

Eosauropterygia indet. cf. Nothosaurus

Middle Triassic, Gogolin Beds, Upper Silesia, Poland

The specimen is a very well-preserved cervical vertebral centrum of an unidentified Middle Triassic aquatic reptile belonging to the clade Eosauropterygia.

The specimen measures 15 mm in length. The posterior articular surface measures 10 mm and width 12 mm. Anteriorly, it measures 11 mm in height and 12 mm in width.

The dorsal view shows a perfectly preserved structure of the neurocentral suture and the floor of the neural canal. In lateral view, the centrum assumes a centrally narrowed, slightly hourglass shape. The lateral surfaces show well-preserved parapophyses located near the ventral margin.

In ventral view, the centrum is quite flat. There is no distinct ventral keel. A slight conical thickening is visible only near the articular surfaces.

Both articular surfaces are slightly amphicoelic. The anterior aspect is significantly better preserved, while the posterior aspect shows signs of erosion, particularly closer to the dorsal margin. The anterior articular surface is wider and higher, appearing more concave than the opposite aspect. However, the difference in dimensions may be due to better preservation.

The overall elongated proportions, hourglass shape in lateral view, and distinct, lateroventrally placed parapophyses strongly indicate a cervical vertebral centrum. Its dimensions highly suggest a medium-sized or large member of the Eosauropterygia.

The specimen comes from the Gogolin Beds – a formation of the Lower Muschelkalk – hence Nothosaurus marchicus is a likely candidate – however, the isolated vertebral body prevents me from going beyond this tenuous hypothesis.