Chunerpeton
Chunerpeton is an extinct genus of salamander from the Middle or Late Jurassic Daohugou Beds in Ningcheng County, Nei Mongol, China, containing the only species Chunerpeton tianyiensis. It was a small animal measuring in length, and was neotenic, with the retention of external gills into adulthood.
In the original description it was placed in Cryptobranchidae, which contains modern giant salamanders. A redescription published in 2020 found it to be a stem-group caudatan outside the crown group of modern salamanders. A 2021 study found it to be a member of Cryptobranchoidea outside of Cryptobranchidae. In 2022, a more extensive analysis, with greater character and taxon sampling, also recovered Chunerpeton as a stem-group caudatan, outside the crown group of modern salamanders, and associated with Beiyanerpeton and Qinglongtriton.
Chunerpeton has been used to constrain the age of Cryptobranchoidea in over a dozen molecular divergence analyses, but given the uncertain affinity of the taxon it should perhaps no longer be used in this way. It lived alongside likely stem-group salamanders, such as Jeholotriton, Liaoxitriton, and Pangerpeton, all of which lived at the same age.