Updated March 15, 2017 with higher resolution data.
The first known basal tetrapod with a five-toed pes is
Pederpes finneyae (Clack 2002; Tournasian, early Carboniferous, 348mya; 1m in est. length) and it is known from a fairly complete articulated skeleton. In an attempt to reconstruct the skull I have colored elements (Fig. 1) and moved those tracings to a reconstruction in which some of the broken loose pieces have been replaced to their in vivo positions.
The lacrimal, maxilla and jugal
have broken parts that fit together like puzzle pieces. I did not realize the premaxilla was rotated, along with the lower jaw tip, such that in appeared in more dorsal view.
In the large reptile tree
Pederpes now nests with Whatcheeria.
Clack JA 2002. An early tetrapod from ‘Romer’s Gap’. Nature. 418 (6893): 72–76.