The kuehneosaurids were a group of small, lizard-like diapsid

Diapsid

Diapsids are a group of reptiles that developed two holes in each side of their skulls, about 300 million years ago during the late Carboniferous period. Living diapsids are extremely diverse, and include all crocodiles, lizards, snakes, and tuatara...

s including Icarosaurus

Icarosaurus

Icarosaurus is a genus of reptile from the Late Triassic Lower Lockatong Formation of New Jersey, dated to around 228 million years ago. It is closely related to lizards and the tuatara...

and Kuehneosaurus

Kuehneosaurus

Kuehneosaurus is an extinct genus of Late Triassic reptile from the United Kingdom. Measuring 72 centimetres long , it had "wings" formed from ribs which jutted out from its body by as much as 14.3 cm, connected by a membrane which allowed it to slow its descent when jumping from trees...

. They were distinguished from other diapsids by their 'wings', which were really sails of skin held up by bony struts similar to ribs. These sails would have served as gliding tools, but the Kuehneosaurids were incapable of powered flight. They were most likely insectivorous, judging from their pin-like teeth. The oldest known member is Pamelina

Pamelina

Pamelina is an extinct genus of basal kuehneosaurid known from Early Triassic rocks of Czatkowice 1, Poland. It was first named by Susan E. Evans in 2009 and the type species is Pamelina polonica. It is the oldest known member of Kuehneosauridae.- Phylogeny :Cladogram after Evans ....

.

Rhabdopelix

Rhabdopelix

Rhabdopelix is a genus of possible kuehneosaurid reptile, from the Late Triassic-age Lockatong Formation of Pennsylvania, USA. Based on partial, possibly chimeric remains, it was described by American naturalist and paleontologist Edward Drinker Cope as an early pterosaur...

may have been a kuehneosaurid; however, the fossils were lost, and the characteristics described are not entirely consistent with the other family members.