Wynd, Newbitt and Heckert 2018
“redescribe Doswellia sixmilensis on the basis of extensive repreparation of the skull material to identify cranial elements, morphological details previously not described, and cranial suture patterns. As such, we reinterpret what was previously regarded as the antorbital fenestra to be the orbit and, as a consequence, the identification of bones and the diagnosis of the taxon must be substantially modified.”
Today I learned
the larger rostrum was attributed to a second Doswellia species, D. sixmilenesis. (Heckert et al. 2012). The reconstructions below created a chimaera of the two skulls, and two reconstructions based on the old and new interpretations of the larger rostrum.
the sum of the parts largely match sister taxa (Fig. 2) in the large reptile tree (LRT, 1315 taxa).
The taxon list for the abstract
was not published, but I hope it includes the taxa used in the LRT where Doswellia nests closer to certain proterochampsids than to proterochampsids.
The authors report,
“What is clear, is that D. sixmilensis shares character states with typical proterochampsians (e.g., rimmed orbit) that are not found in D. kaltenbachi.” In the first (earlier) reconstruction (Fig. 1), the orbits were not preserved, except ventrally by the large jugal.
The genus Doswellia
is distinct from all other genera, but trait scores nest it closest to a derived proterosuchid, the SAMPK K10603 specimen (Figs. 1, 2).
Dilkes D and Sues H-D 2009. Redescription and phylogenetic relationships of Doswellia kaltenbachi (Diapsida: Archosauriformes) from the Upper Triassic of Virginia. Journal of Vertebrate Paleontology 29(1):58-79
Heckert AB, Lucas SG and Spielmann JA 2012. A new species of the enigmatic archosauromorph Doswellia from the Upper Triassic Bluewater Creek Formation, New Mexico, USA. Palaeontology 55(6):1333–1348.
Weems RE 1980. An unusual newly discovered archosaur from the Upper Triassic of Virginia, U.S.A. Transactions of the American Philosophical Society, New Series 70(7):1-53.
Wynd BM, Nesbitt SJ, Heckert AB 2018. Skull elongation in stem archosaur cranial displarity: Reevaluationg Doswellia sixmilensis (Archosauriformes: Proterochampsia) to examime phylogenetic distribution of morphological disparity. SVP Abstracts.