They were medium-sized temnospondyls with wedge-shaped tails, narrow skulls, and, in advanced forms, elongated snouts.

The largest and most specialized family, the Trematosauridae, are the only batrachomorphs to have adapted to a marine lifestyle with the exception of the modern crab-eating frog.

A temnospondyl ilium was described in 2004 from the Callovian Toutunhe Formation in the Junggar Basin of China.

The presence of this bone in the Toutunhe Formation extends the range of trematosauroids into the Middle Jurassic, making it one of only three groups of temnospondyls that survived the Triassic-Jurassic extinction event (the other two being the Brachyopoidea and possibly the Capitosauria).

[1] Below is a cladogram modified from Schoch (2011):[2] Uranocentrodon Lydekkerina Rhytidosteidae Siderops Batrachosuchus Laidleria Plagiosuchus Gerrothorax Capitosauria Lyrocephaliscus Trematolestes Inflectosaurus Microposaurus Jordan taxon Almasaurus Callistomordax