Trematospondylus, a long-forgotten middle Jurassic plesiosaur

Described in 1858, Trematospondylus macrocephalus from the Bathonian (Middle Jurassic) of Germany is one of the earliest established plesiosaur taxa. However, despite being historically significant, the taxon disappeared from the literature shortly after its initial description and has not been mentioned for over a century. The new study shows that Trematospondylus most likely belongs to the Rhomaleosauridae and represents a large-bodied member of this archaic clade. The material adds to the rare Middle Jurassic record of rhomaleosaurids and enhances our knowledge of the plesiosaur diversity during the pre-Callovian Middle Jurassic, which has been very limited.

Reconstruction: Dmitry Bogdanov