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New squamates from Cretaceous and Eocene



From: Ben Creisler
bcreisler@gmail.com


A couple of new on-dino papers about squamates:

Alexandra Houssaye, Nathalie Bardet, Iván Narváez & Francisco Ortega (2013)
Squamate finding in “Lo Hueco” (Late Campanian-Early Maastrichtian,
Cuenca Province, Spain): the second non-marine pythonomorph lizard.
Paläontologische Zeitschrift (advance online publication)
DOI: 10.1007/s12542-013-0164-6
http://link.springer.com/article/10.1007/s12542-013-0164-6

Two squamate vertebrae were discovered in the site of “Lo Hueco”
(Cuenca, Spain; Late Campanian-Early Maastrichtian), which has yielded
a rich and diversified fossil fauna. Their anatomical and
microanatomical features are described. They reveal that these
vertebrae probably belong to a new genus of Pythonomorpha. This taxon
corresponds to the second non-marine pythonomorph lizard hitherto
described. Anatomical, microanatomical and sedimentological data
suggest a terrestrial or amphibious mode of life. This discovery
raises questions about the evolutionary history of pythonomorph
lizards in non-marine deposits.


===

Alexandra Houssaye, Jean-Claude Rage, Nathalie Nardet, Peggy Vincent,
Mbarek Amaghzaz and Said Meslouh (2013)
New highlights about the enigmatic marine snake Palaeophis
maghrebianus (Palaeophiidae; Palaeophiinae) from the Ypresian (Lower
Eocene) Phosphates of Morocco.
Palaeontology (advance online publication)
DOI: 10.1111/pala.12008
http://onlinelibrary.wiley.com/doi/10.1111/pala.12008/abstract

Palaeophis maghrebianus belongs to the Palaeophiinae (Palaeophiidae).
This snake subfamily is relatively poorly known, and it is mainly
represented by disarticulated vertebrae and ribs and by a few
vertebral segments. Its intracolumnar variability remains also poorly
understood. The discovery of new isolated vertebrae and vertebral
segments of Palaeophis maghrebianus in the Ypresian (Lower Eocene)
Phosphates of Morocco enables us to provide a more detailed diagnosis
of this species and to describe its intracolumnar variability.
Moreover, the new material reveals that this species could reach
gigantic size being, with Palaeophis colossaeus, one of the two longer
palaeophiids. The microanatomical and histological analysis of some
vertebrae illustrating diverse positions along the vertebral column
reveals the presence of osteosclerosis, especially in the anterior and
mid-precloacal regions. The occurrence of this osseous specialization
implies a role in buoyancy and body trim control in this taxon, which
is considered a shallow marine dweller based on its anatomical
features and geological data. Palaeophis maghrebianus also displays a
dense vascular network suggesting a growth speed, and thus a metabolic
rate, much higher than in the biggest extant snakes.