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New non-dino Mesozoic vertebrate papers



From: Ben Creisler
bh480@scn.org

A few new papers about non-dino/avian Mesozoic vertebrates with a couple of
new taxa:


TÉO VEIGA DE OLIVEIRA, CESAR LEANDRO SCHULTZ, MARINA BENTO SOARES & CARLOS
NUNES RODRIGUES (Brazil) (2011)
A new carnivorous cynodont (Synapsida, Therapsida) from the Brazilian
Middle Triassic (Santa Maria Formation): Candelariodon barberenai gen. et
sp. nov. 
Zootaxa 3027: 19?28 
First page: http://www.mapress.com/zootaxa/2011/f/z03027p028f.pdf

A new small cynodont, Candelariodon barberenai gen. et sp. nov., from the
Middle Triassic of Brazil (Santa Maria Formation) is reported. The new
taxon is represented by a partial mandible having some complete teeth. The
morphology of the dentary and splenial is similar to other carnivorous
cynodonts, except for the absence of the angular process of the dentary.
The anterior-most lower teeth are slightly expanded buccolingually with a
tall and posteriorly curved main cusp and one or two accessory cusps. The
posterior-most preserved lower postcanine, however, has lingual and buccal
rows of cusps, each formed by four anteroposteriorly aligned cusps,
separated by a shallow basin. This tooth resembles the posterior-most lower
teeth of Aleodon Crompton 1955 from the Middle Triassic of Tanzania, but
the anterior-most teeth of Candelariodon and Aleodon are essentially
different. In this context, the phylogenetic relationships of the new taxon
remain unclear until the discovery of more informative material.


R. A. Elgin & H.B.N. Campos (2011)
A new specimen of the azhdarchoid pterosaur Tapejara wellnhoferi.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2011.613467
http://www.tandfonline.com/doi/abs/10.1080/08912963.2011.613467

A new specimen of the Early Cretaceous azhdarchoid Tapejara wellnhoferi is
described from the Romualdo Member of the Santana Formation, NE Brazil,
providing the first detailed account of the postcranial skeleton. Although
limited in its preservation, the osteology is typical of other azhdarchoid
pterosaurs from these deposits and represents a juvenile animal with a
relatively small wing span of < 1.5 m. The ratios of the pedal elements are
identical to those noted for larger, indeterminate azhdarchoids of the Nova
Olinda Member of the Crato Formation, where the unguals of the pes are
greatly enlarged relative to those of the ornithocheiroids that
co-inhabited the Santana lagoon. The ratios of these elements suggest that,
as part of a larger suite of characters, these animals were likely better
adapted for life on the ground than their ornithocheiroid relatives.


Valentin Fischer, Edwige Masure, Maxim S. Arkhangelsky & Pascal Godefroit
(2011)
A new Barremian (Early Cretaceous) ichthyosaur from western Russia.
Journal of Vertebrate Paleontology 31(5): 1010-1025
DOI:10.1080/02724634.2011.595464
http://www.tandfonline.com/doi/abs/10.1080/02724634.2011.595464

A new ophthalmosaurid ichthyosaur, Sveltonectes insolitus, gen. et sp.
nov., is described from a sub-complete and three-dimensionally preserved
specimen from the late Barremian of western Russia. This new taxon is
supported by 11 cranial, dental, and postcranial autapomorphies, and is
also characterized by features previously considered as autapomorphic for
some other Ophthalmosauridae, such as a processus narialis on the
prefrontal and relatively long hind fins with pre- and postaxial accessory
digits. We conducted a new phylogenetic analysis of Thunnosauria, which
supports a ?Stenopterygius? origin for Ophthalmosauridae. Sveltonectes is
regarded as the sister taxon of Aegirosaurus, which shares a similar skull
roof construction. Contrary to most other Cretaceous ichthyosaurs,
Sveltonectes is characterized by delicate and sharply pointed teeth,
confirming that the ophthalmosaurids were ecologically highly diversified
during the Early Cretaceous.

HANNAH CAINE and MICHAEL J. BENTON (2011)
Ichthyosauria from the Upper Lias of Strawberry Bank, England.
Palaeontology 54(5): 1069?1093
DOI: 10.1111/j.1475-4983.2011.01093.x
http://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2011.01093.x/abstract

Eight remarkably preserved specimens of ichthyosaurs from the lower
Toarcian (Lower Jurassic) of Strawberry Bank (Ilminster, Somerset, England)
are described fully for the first time. Whereas previously these
ichthyosaurs were assigned to one species, Stenopterygius hauffianus, our
study shows there are two, Stenopterygius triscissus and Hauffiopteryx
typicus. S. triscissus is a small- to medium-sized ichthyosaur up to 3.5 m
long, characterised by three apomorphies: long and slender rostrum, large
elliptical supratemporal fenestra and bipartite pelvis. H. typicus is a
small ichthyosaur up to 2.95 m long, with five apomorphies: short and
extremely slender rostrum, very large orbit, small rounded supratemporal
fenestra and tripartite pelvis, which is fused distally. Cladistic analysis
is equivocal about their relationships, suggesting either that
Hauffiopteryx and perhaps also Stenopterygius are members of a clade
Eurhinosauria or that this clade does not exist, and both genera are
members of a wider clade Thunnosauria. Further, the clade Stenopterygiidae,
in which Hauffiopteryx had been located, is not identified. Most striking
is that the specimens are all juveniles (five specimens) or infants (three
specimens), ranging from one-tenth to one-half the normal adult length of
the species.


Takuya Konishi, Donald Brinkman, Judy A. Massare & Michael W. Caldwell
(2011)
New exceptional specimens of Prognathodon overtoni (Squamata, Mosasauridae)
from the upper Campanian of Alberta, Canada, and the systematics and
ecology of the genus.
Journal of Vertebrate Paleontology 31(5): 1026-1046
DOI:10.1080/02724634.2011.601714
http://www.tandfonline.com/doi/abs/10.1080/02724634.2011.601714

Currently known from the early Campanian to late Maastrichtian,
Prognathodon constitutes a group of mosasaurine mosasaurs that typically
possessed massive jaws. Only four articulated skulls are known to date and
the information concerning their postcrania remains minimal. Moreover, the
early to middle Campanian specimens of the taxon are extremely rare and
fragmentary. Two new specimens of Prognathodon overtoni from the early late
Campanian (ca. 74.5 Ma) Bearpaw Formation exposed near Welling, southern
Alberta, Canada, provide the first fully articulated skeletons of the
genus. Detailed morphological assessment of these and pre-existing
specimens indicates that many cranial characters are shared between P.
overtoni and the generic type P. solvayi from the early Maastrichtian,
including (1) short premaxillary-maxillary suture; (2) short triangular
frontal with marked anterior constriction; and (3) distinct, blind-ended
median opening on medullary floor of basioccipital. These are interpreted
as generically diagnostic characters, and the first character in particular
distinguishes Prognathodon from Liodon and other long-snouted mosasaurines.
The postcranium of P. overtoni is lightly built, and differs very little
from that of Clidastes, a basal mosasaurine. Marginal teeth are carinate
with fine crenulations, indicating their proposed opportunistic predatory
behavior. Additionally, most of the fully erupted teeth exhibit a similar
degree of apical wear, which is interpreted as indicating that the taxon
regularly handled prey items that involved crunching. To augment these
dietary inferences, gut contents from one of the new specimens include
fragments of a large and a small fish, a sea turtle, and possibly a
cephalopod.



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