New Early Permian(!) iguanid lizard found vulcanized!

This page was again modified March 17, 2018 to reflect an new nesting for Ascendonanus as a basal iguanid. 

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, now Ascendonanus) approximately 14 cm snout to vent. Despite its apparent similarity to an iguanid, 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 iguanids.

Figure 1. Click to enlarge. The Early Permian reptile (TA1045) preserved in volcanic debris, from Roßler et al. 2012. Yes, those are transverse belly scales beneath the ribs.It looks like the complete rostrum was preserved, right to the edge of the matrix. This image is considered low in resolution. More details can be gleaned with better images.

Figure 1. Click to enlarge. This low-rez image was used in 2012 to create these images. See figure 2 for an update. The Early Permian reptile (TA1045) preserved in volcanic debris, from Roßler et al. 2012. Yes, those are transverse belly scales beneath the ribs.It looks like the complete rostrum was preserved, right to the edge of the matrix. This image is considered low in resolution. More details can be gleaned with better images.

Phylogenetic analysis
Using DGS to tease out the details, then adding this taxon to the large reptile tree nests TA1045 as a sister to Liushusaurus an extinct iguanid. And that makes Ascendonanus the oldest known squamate.

Figure 1. The skull of Ascendonanus has a diapsid temporal configuration with clearly visible upper temporal fenestra and a typical iguanid skull morphology.

Figure 1. The skull of Ascendonanus has a diapsid temporal configuration with clearly visible upper temporal fenestra and a typical iguanid skull morphology.

Soft tissue
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.

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.

References
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.

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