Doleserpeton annectus (Sigurdsen and Bolt 2010) Early Permian~290 mya, ~8 cm in length. Derived from a sister to Utegenia and Amphibamus, Doleserpeton phylogenetically preceded Gerobatrachus and other proto frogs.
Distinct from Amphibamus, the skull of Doleserpeton had a rounder profile and a much deeper otic notch. The palatines were tiny and directed medially. The pterygoids lost their medial connections to the vomers and were broadly separated and diagonally directed toward the base of the orbit. The parasphenoid and basipterygoid were much enlarged. The teeth were tiny and bicuspid (pedicellate), as in frogs.
The presacral number decreased to 24. Two sacral vertebrae were present. The dorsal ribs were more gracile. The caudal ribs were reduced in number and size.
The clavicles were reduced. The scapulocoracoid was shorter. The forelimb was more shorter and more gracile. Manual digit 5 may have been absent here because no succeeding taxa have it. The hand was more robust than the foot.
The dorsal process of the ilium was angled posteriorly. The hind limb was shorter and more gracile.