This page was again modified May 21, 2015 to reflect an new nesting for TA 1045 as a basal varanid.
Rößler et al. (2012) just published an account of an Early Permian ecosystem preserved by explosive volcanism. Among the illustrated creatures was a single, reptile (Fig. 1, TA1045) approximately 14 cm snout to vent. Despite its apparent similarity to a varanid, it was not immediately apparent what sort of reptile this was to Rößler et al. TA 1045 was included in the large reptile tree and it indeed nested with basal varanids.
Using DGS to tease out the details, then adding this taxon to the large reptile tree nests TA1045 as a sister to Estesia, an extinct varanid, and Bahndwivici, a basal varanoid. And that makes it the oldest known ancestor of living lizards.
Flesh and a complete series of belly scales wider than the ribcage make the vulcanized reptile even more interesting, despite the lack of good preservation of the feet and hands.
Distinct from the skull of Bahndwivici, TA1045 had a larger orbit, more laterally oriented. The maxilla has a convex ventral margin. Larger and fewer teeth lined the jaws. The mandible was more gracile. The torso was long and sinuous. Wide ventral scales protected the belly. The scapula was highly fenestrated. The hind limbs were much more robust than the forelimbs.
Chronology – This is Where it Gets REALLY Exciting!!
TA1045 pushes the fossilized origins of the lepidosauriformes way back to the early part of the Early Permian (290 mya), within 10 million years of the Carboniferous (Pennsylvannian). That means more primitive lepidosaurs deep into the Pennsylvannian. There must have been an explosive radiation of new lepidosauromorphs at that time, currently unknown as fossils.
Rößler R, Zierold T, Feng F, Kretzschmar R, Merbitz M, Annacker V and Schneider JW 2012. A snapshot of an Early Permian ecosystem preserved by explosive volcanism: new results from the Chemnitz Petrified Forest, Germany.PALAIOS 27(11):814-834. pdf online.