Trypanognathus remigiusbergensis (Schoch and Voigt 2019; latest Carboniferous) This is a late-surviving specimen of the first taxon in the LRT with fingers, toes and dorsal nares. It nests in a more basal position than originally thought, between Panderichthys and Lairleria.

Derived states are the penetration of vomerine tusks through the splenial and symphyseal tusks through the premaxilla. Trypanognathus shares with dvinosauroids the lack of a squamosal embayment, an elongated basipterygoid process, a foreshortened palatine ramus exclusively reaching the ectopterygoid, the absence of pterygoid denticles, and enlarged palatal tusks. The body is elongate with well-ossified, but small limbs, the presacral count is ca. 28, and the pleurocentra are large and reached ventrally almost as far as the intercentrum.

Click here for more on Trypanognathus breathing and evolution.

Laidleria gracilis (Kitching 1957; Warren 1998; Early Triassic) Originally considered a trematosaur and long considered an enigma taxon, Lairdleria was a small, flat head, wide body basal dvinosaur with a trinagular skull in dorsal view. Apparently the intertemporals, prefrontals and an interfrontal were overlooked by Warren 1998. Here it nests with Brindabellaspis from the Early Devonian.