New information on amphibamids (Tetrapoda, Temnospondyli) from Richards Spur (Fort Sill), Oklahoma

ABSTRACT A nearly complete amphibamid skull from the Richards Spur locality in Oklahoma is demonstrated to be a new species of Tersomius. This new species has a mosaic of features seen in other amphibamids, and appears to fall on the Amphibamus side of the amphibamid basal dichotomy of some authors. This specimen also calls into question the validity of the Tersomius assignment of a large specimen from the Texas Red Beds. One feature of note is the presence of a weakly bicuspid fang on one of the vomers. This poorly developed feature is present only on an unattached replacement cusp, and appears to have been rapidly worn away through use. This is the first potential bicuspid palatal fang known from an amphibamid. A second partial skull is assigned to the recently described species Pasawioops mayi. A micro-computed tomographic reconstruction shows a prominent ventral flange of the nasal that meets a counterpart from the prefrontal and palatine to wall the nasal capsule posteriorly. The nasolacrimal canal s...