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New Cretaceous squamate papers



From: Ben Creisler
bcreisler@gmail.com

Some new and recent non-dino papers not mentioned yet:


Hong-Yu Yi and Mark A. Norell (2013)
New Materials of Estesia mongoliensis (Squamata: Anguimorpha) and the
Evolution of Venom Grooves in Lizards.
American Museum Novitates 3767 :1-31
doi: http://dx.doi.org/10.1206/3767.2
http://www.bioone.org/doi/abs/10.1206/3767.2
[not yet posted on the AMNH site with open access:
http://digitallibrary.amnh.org/dspace/handle/2246/9]



New specimens of the fossil lizard Estesia mongoliensis are described
from the Upper Cretaceous of Mongolia. Phylogenetic analysis of 86
anguimorph taxa coded with 435 morphological characters and four genes
confirms the placement of Estesia mongoliensis in a monophyletic
Monstersauria. Extant monstersaurs, the genus Heloderma, are the only
extant lizards bearing venom-transmitting teeth with a deep venom
grove in the rostral carina. Compared to the crown group, stem
monstersaurs are morphologically more variable in venom-delivery
apparatus. This study has found that Estesia mongoliensis has two
shallow grooves in the rostral and caudal carinae of its dentary
teeth, demonstrating a primary venom-delivery apparatus. A summary of
venom-delivering tooth specialization in the Anguimorpha is provided,
and related morphological characters are optimized on the strict
consensus tree resulting from the combined morphological and molecular
analysis of anguimorph phylogeny The phylogeny supports a single
origination of venom grooves in the Monstersauria, and indicates that
grooved teeth are currently the only reliable venom-delivery apparatus
to be recognized in fossil lizards.

===
Arcanosaurus

Alexandra Houssaye, Jean-Claude Rage, Fidel Torcida Fernández-Baldor,
Pedro Huerta, Nathalie Bardet & Xabier Pereda Suberbiola (2012)
A new varanoid squamate from the Early Cretaceous (Barremian–Aptian)
of Burgos, Spain
Cretaceous Research (advance online publication)
doi: http://dx.doi.org/10.1016/j.cretres.2012.11.005
http://www.sciencedirect.com/science/article/pii/S0195667112001723


A new anguimorph lizard from the late Barremian–Aptian of the Salas de
los Infantes area (Cameros Basin, Iberian Peninsula) is described here
as Arcanosaurus ibericus gen. et sp. nov. It corresponds to the first
squamate remains from the Burgos Province. The unique combination of
morphological and microanatomical characters enables us to erect a new
genus and species that we tentatively assign to Varanoidea despite the
strange seemingly absence on the axis of a posterior hypapophysis. The
combination of both microanatomical and geological data suggests an
essentially terrestrial mode of life. This discovery reveals itself
particularly interesting concerning the evolutionary history of
varanoids as this new Spanish taxon might correspond to the oldest
terrestrial varanoid known to date.

===

Annie S. Hsiou, Adriana M. Albino, Manuel A. Medeiros, and Ronny A.B.
Santos (2013)
The oldest Brazilian snakes from the early Late Cretaceous (Cenomanian).
Acta Palaeontologica Polonica (in press)
doi: http://dx.doi.org/10.4202/app.2012.0091
http://app.pan.pl/article/item/app20120091.html


South American Mesozoic snake diversity is mostly represented by
genera from the Cenomanian (Najash), Santonian-Campanian (Dinilysia),
and Campanian-Maastrichtian(Alamitophis, Patagoniophis, Rionegrophis,
and Australophis) of Patagonia, Argentina. In this paper, we describe
a new snake genus and species, Seismophis septentrionalis, from the
early Late Cretaceous (Cenomanian) of the Alcântara Formation,
Maranhão, northeastern Brazil. The new snake comprises a posteriormost
trunk vertebra and possibly a poorly preserved midtrunk vertebra. Both
vertebrae share small size, zygosphene moderately thick with a
rectilinear roof, absence of paracotylar foramina, presence of
parazygantral foramina, and strongly marked parasagittal ridges of the
neural arch. The new snake is here considered of uncertain systematic
affinities, but probably close to the limbed snake Najash rionegrina.
Although the material is very fragmentary and the systematic
assignment is still unresolved, this snake represents the oldest, as
well as probably the most primitive snake from Brazil.


==
And a new turtle paper:


Edwin A. Cadena, Daniel T. Ksepka and Mark A. Norell (2013)
New material of Mongolemys elegans Khosatzky and Mlynarski, 1971
(Testudines: Lindholmemydidae), from the Late Cretaceous of Mongolia
with Comments on Bone Histology and Phylogeny.
American Museum Novitates 3766 :1-28. 2013
doi: http://dx.doi.org/10.1206/3766.2
http://www.bioone.org/doi/abs/10.1206/3766.2
[not yet posted on the AMNH site with open access:
http://digitallibrary.amnh.org/dspace/handle/2246/9]


Mongolemys elegans Khosatzky and Mlynarski, 1971, is a freshwater
lindholmemydid turtle that is very abundant in Late Cretaceous
(Maastrichtian) pond deposits from the Gobi Desert of Mongolia. Here,
we present new data on the morphology, bone histology, and
phylogenetic position of M. elegans based on hatchlings, juveniles,
and adults collected by American Museum of Natural History and the
Mongolian Academy of Sciences joint field expeditions at the Bugin
Tsav locality. Phylogenetic analysis using a morphological dataset
supports the placement of M. elegans as a stem testudinoid. Bone
histology of M. elegans shows similar patterns of thickness and bone
tissue type for the internal and external cortexes as in other
freshwater turtles. Microstructural samples of fossil bone from M.
elegans show exceptional preservation of osteocyte lacuno-canicular
networks, and higher values of osteocyte density at the external
cortex in contrast to cancellous bone and the internal cortex.