Acheloma and Platyhystrix

Acheloma cumminsi (Cope 1882; Dilkes and Reisz 1987; Early Permian, 275 mya; aka Trematops) was originally considered a temnospondyl, but here nests with Dendrerpeton within the lepospondyls with many traits convergent with temnospondyls, like a large wide skull.

Acheloma dunni skull shown below. It has giant palatal teeth. Scale bar = 5 cm.

Platyhystrix rugosus (Case 1910 (1911), Berman, Reisz and Fracaso 1981; Early Permian, 300 mya; 1m length) was a sister to Acheloma in the LRT, although it was traditionally allied with Cacops before the skull was described by Berman et al. 1981 and only the spines were known. A confluent naris/antorbital fenestra is apparent. In dorsal view the skull has straight lateral edges. The postorbital is much larger and rugose.

Berman et al. 1981 list AMNH 4785 as the holotype for Platyhystrix, but that museum number brings up Aspidosaurus. Williston 1911 documented other specimens.

Berman DS, Reisz RR and Fracasso MA 1981. Skull of the Lower Permian dissorophid amphibian Platyhystrix rugosus. Annals of the Carnegie Museum 50 (17):391-416.

Case EC 1911. Revision of the Amphibia and Pisces of the Permian of North America. Publ. Carnegie Inst. Washington 146:1-179.

Dilkes DW and Reisz R 1987. Trematops milleri identified as a junior synonym of Acheloma cumminsi with a revision of the genus. American Museum Novitates 2902.

Lewis GE and Vaughn PP 1965. Early Permian vertebrates from the Cutler Formation of the Placerville area, Colorado, with a section on Footprints from the Cutler Formation by Donald Baird: U.S. Geol. Survey Prof. Paper 503-C, p. 1-50.

Williston SW 1911a. A new family of reptiles from the Permian of New Mexico. American Journal of Science 31:378-398.

Williston SW 1911b. American Permian vertebrates. University of Chicago Press: 145 pp.

wiki/Acheloma
wiki/Platyhystrix

Lissamphibia

Trimerorhachis

Cacops

Dissorophus

Acheloma

Fedexia

Tersomius

Dendrerpeton

Salamanders and Frogs