Yates and Warren also named Dvinosauria , a clade of small aquatic temnospondyls from the Carboniferous , Permian , and Triassic . They placed Dvinosauria within Limnarchia , but more recent studies disagree on their position . For example , a 2007 study places them even more basal than euskelians , while a 2008 study keeps them as basal limnarchians .