Pederpes

Pederpes Temporal range: Tournasian, Early Carboniferous 348–347.6 Ma PreЄ Є O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Superclass:	Tetrapoda
Family:	Whatcheeriidae
Genus:	Pederpes Clack, 2002
Species
P. finneyae Clack, 2002 (type)

P. finneyae Clack, 2002 (type)

Pederpes ('Peter's Foot') is an extinct genus of early Carboniferous tetrapod, dating from 348 - 347.6 Ma in the Tournaisian age (lower Mississippian). Pederpes contains one species, P. finneyae, 1 m long.

This most basal Carboniferous tetrapod had a large, somewhat triangular head, similar to that of later American sister-genus Whatcheeria, from which it is distinguished by various skeletal features, such as a spike-like latissimus dorsi (an arm muscle) attachment on the humerus and several minor skull features. The feet had characteristics that distinguished it from the paddle-like feet of the Devonian Ichthyostegalia and resembled the feet of later, more terrestrially adapted Carboniferous forms. Pederpes is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and despite the probable presence of a sixth digit on the forelimbs it was at least functionally pentadactyl.

Pederpes was discovered in 1971 in central Scotland and classified as a lobe-finned fish. Its fossils were found in the Ballagan Formation. The type specimen was a nearly complete, articulated skeleton. Only the tail and some bones of the skull and limbs were missing. It was not until 2002 that Jennifer Clack named and reclassified the fossil as a primitive tetrapod.

Pederpes is placed in the family Whatcheeriidae, of uncertain relationships to other tetrapod families. While an amphibian in the broad sense, under cladistic taxonomy, Pederpes is not considered an amphibian in the meaning of modern amphibians. As a very basal (primitive) tetrapod, it falls under the traditional class Amphibia in Linnaean taxonomy.