Megachirella redescribed

A new paper (Renesto and Bernardi 2013) redescribing the basal lepidosaur Megachirella has appeared. Earlier we looked at this crushed specimen.


Figure 1. Megachirella. Click to learn more.

From the abstract (which is all I’ve seen so far):
Megachirella wachtleri Renesto et Posenato, 2003, a well preserved partial reptile skeleton from the Middle Triassic of the Dolomites (N. Italy), was originally considered a lepidosauromorph, but no phylogenetic analysis was carried out. Consequently, the taxon was overlooked in later phylogenetic analyses of the Diapsida. Here, the holotype and only known specimen of M. wachtleri is redescribed, allowing an investigation of its phylogenetic relationships. Phylogenetic analyses confirm that Megachirella is a lepidosauromorph close to the crown group lepidosaurs (Squamata + Rhynchocephalia). Megachirella enhances our knowledge of the series of morphological modifications that led to the origin of the Lepidosauria, the most diverse clade of extant reptiles.

Added after paper was received.
Close to the crown group?

The large reptile tree nests Megachirella within basal Rhynchocephalia, derived from a sister to Gephyrosaurus. That puts it at odds to a “close to” designation. Megachirella nests with Lepidosaurs and Rhynchocephalians and sometimes Marmoretta (Evans 1991), as it does here. So the large reptile tree and the Renesto and Bernardi (2013) results are largely in agreement with regard to Megachirella. The much smaller prior trees, however have multiple problems (=strange bedfellows) based on their small size and occasional reliance on suprageneric taxa.

Click to enlarge. Megachirella was added to several prior trees with these results.

Figure 3. Click to enlarge. Megachirella was added to several prior trees with these results.

Evans SE 1991. A new lizard−like reptile (Diapsida: Lepidosauromorpha) from the Middle Jurassic of Oxfordshire. Zoological Journal of the Linnean Society 103:391-412.
Renesto S and Posenato R 2003. A new lepidosauromorph reptile from the Middle Triassic of the Dolomites (northern Italy). Rivista Italiana di Paleontologia e Stratigrafia 109(3) 463-474. online pdf
Renesto S and Bernardi M 2013. Redescription and phylogenetic relationships of Megachirella wachtleri Renesto et Posenato, 2003 (Reptilia, Diapsida). Paläontologische Zeitschrift (advance online publication) DOI: 10.1007/s12542-013-0194-0


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