Eupneasauridae

Eupneasauridae is a name that has appeared in paleontological literature as a proposed family within Archosauromorpha, a major subset of diapsid reptiles that includes archosaurs and their relatives. The act of designating a formal family is debated because the available fossil material is fragmentary and lacks consistently diagnostic traits.

Because diagnostic features are uncertain, several researchers have treated Eupneasauridae as nomen dubium — a taxon whose name cannot be reliably applied to specimens — or as a possible synonym of other archosauromorph families. As a result, Eupneasauridae has not been maintained as a widely recognized clade in modern phylogenetic analyses.

The referred material comprises limited skeletal remains from terrestrial deposits; due to sparse discoveries and poor preservation, it is unclear how many genera or species, if any, belong to Eupneasauridae, and its precise temporal and geographic distribution remain unresolved.

In discussions of archosauromorph diversity, Eupneasauridae is cited as an example of the challenges of early reptile taxonomy, illustrating issues of fragmentary fossil evidence and the instability of early taxonomic groups before comprehensive phylogenetic frameworks.