Panchen 1959
reported on a 70cm armored basal tetrapod from the Late Permian of Tanzania. Traditionally considered a temnospondyl, Peltobatrachus (Fig. 1) inspired the addition of several basal tetrapod taxa, including taxa that defined the Temnospondyli (see below).
Figure 1. Armored Peltobatrachus.
No teeth or distal limb elements are preserved.
Peltobatrachus is atypical in having wider ribs along their entire length. Related taxa, like Eryops and Sclerocephalus, have only the distal portion of their ribs (intercostal plates) expanded to overlap succeeding ribs.
Intercostal plates disappear in most tetrapods,
but make a reappearance (reversal) in the derived cynodont, Thrinaxodon.
Schoch (2013) defined the clade Temnospondyli
as the least inclusive clade of Edops and Mastodonsaurus. In the large reptile tree (LRT, 1423 taxa), Edops and Mastodonsaurus nest in two adjoining sister clades, the latter in the larger specimen clade of the Lepospondyli, distinct from the smaller specimen clade that includes extant frogs and salamanders.
References
Panchen AL 1959. A new armoured amphibian from the Upper Permian of East Africa. Philosophical Transactions of the Royal Society of London B 242:207-281.
The Pterosaur Heresies 