Marmorerpeton

Marmorerpeton is an extinct genus of prehistoric stem-salamanders that lived in Europe during the Middle Jurassic. They are among the earliest known salamanders, and are probably older than Karaurus. The genus appears to have been neotenic, based on a few morphological characters and on the presence of calcified cartilage in the medulla of its humerus (see thumbnail).

The size of its osteocytic lacunae suggests that it had a fairly large genome (C-value of about 36.7 pg, with a 95% confidence interval ranging from 30.2 to 44.2 pg), though not as large as that of obligatorily neotenic extant urodeles. This suggests that it may have been facultatively neotenic.