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New Doswellia species from Upper Triassic of New Mexico

From: Ben Creisler

A new online paper:

Andrew B. Heckert, Spencer G. Lucas and Justin A. Spielmann (2012)
A new species of the enigmatic archosauromorph Doswellia from the
Upper Triassic Bluewater Creek Formation, New Mexico, USA.
Palaeontology 55(4): 1333–1348
DOI: 10.1111/j.1475-4983.2012.01200.x

Doswellia sixmilensis is a new species of the doswelliid
archosauromorph genus Doswellia named for an incomplete skeleton from
the Upper Triassic Bluewater Creek Formation of the Chinle Group in
west-central New Mexico, USA. D. sixmilensis differs from D.
kaltenbachi Weems, the type and only other known species of Doswellia,
in its larger size, higher tooth count and greater heterodonty,
possession of keels on the cervical centra and the presence of
discrete knobs or spikes on some osteoderms. The holotype of D.
sixmilensis is the fourth occurrence of Doswellia and only the second
occurrence of a Doswellia skull, which includes the previously unknown
premaxilla and maxilla (and therefore the best dentition) and has the
best-preserved cervical vertebrae. Although it adds to our knowledge
of the anatomy of Doswellia, this new information does not alter
previous concepts of the phylogenetic relationships of the doswelliid
genera, largely because they are so poorly known anatomically. The
genus Doswellia is known from the Newark Supergroup in Virginia, and
the Chinle Group in Texas, New Mexico and Utah, in strata of
Otischalkian–Adamanian age. The type locality of D. sixmilensis is c.
43 m stratigraphically below a bed from which U-Pb dating of detrital
zircons yields a maximum depositional age of c. 220 Ma, so this is a
reasonable approximate numerical age for D. sixmilensis.