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Pliosaur feeding biomechanics and other non-dino papers



Ben Creisler
bcreisler@gmail.com

A number of recent non-dino papers and two papers now with free pdfs:

Davide Foffa, Andrew R. Cuff, Judyth Sassoon, Emily J. Rayfield, Mark
N. Mavrogordato  and Michael J. Benton (2014)
Functional anatomy and feeding biomechanics of a giant Upper Jurassic
pliosaur (Reptilia: Sauropterygia) from Weymouth Bay, Dorset, UK.
Journal of Anatomy (advance online publication)
DOI: 10.1111/joa.12200
http://onlinelibrary.wiley.com/doi/10.1111/joa.12200/abstract

Pliosaurs were among the largest predators in Mesozoic seas, and yet
their functional anatomy and feeding biomechanics are poorly
understood. A new, well-preserved pliosaur from the Kimmeridgian of
Weymouth Bay (UK) revealed cranial adaptations related to feeding.
Digital modelling of computed tomography scans allowed reconstruction
of missing, distorted regions of the skull and of the adductor
musculature, which indicated high bite forces. Size-corrected beam
theory modelling showed that the snout was poorly optimised against
bending and torsional stresses compared with other aquatic and
terrestrial predators, suggesting that pliosaurs did not twist or
shake their prey during feeding and that seizing was better performed
with post-symphyseal bites. Finite element analysis identified
biting-induced stress patterns in both the rostrum and lower jaws,
highlighting weak areas in the rostral maxillary-premaxillary contact
and the caudal mandibular symphysis. A comparatively weak skull
coupled with musculature that was able to produce high forces, is
explained as a trade-off between agility, hydrodynamics and strength.
In the Kimmeridgian ecosystem, we conclude that Late Jurassic
pliosaurs were generalist predators at the top of the food chain, able
to prey on reptiles and fishes up to half their own length.

===

A. O. Averianov & E. V. Popov (2014)
A pterosaurian vertebra from the Upper Cretaceous of the Saratov Region.
Paleontological Journal 48(3): 326-329
DOI: 10.1134/S0031030114030034
http://link.springer.com/article/10.1134/S0031030114030034

A dorsal vertebra referred to as Azhdarchidae indet. from the Rybushka
Formation (Upper Cretaceous, Lower Campanian) of the Beloe Ozero
locality in the Saratov Region is described. Its vertebral centrum has
a hypapophysis and, at the base of the neural arch, there is a large
pneumatic foramen. The vertebra possibly belongs to Volgadraco
bogolubovi Averianov, Arkhangelskii et Pervushov, 2008, described from
the Rybushka Formation of the Shirokii Karamysh 2 locality in the
Saratov Region.

==
Henri Cappetta, Nathalie Bardet, Xabier Pereda Suberbiola, Sylvain
Adnet, Driss Akkrim, Mohamed Amalik & Aziza Benabdallah (2014)
Marine vertebrate faunas from the Maastrichtian phosphates of
Benguérir (Ganntour Basin, Morocco): Biostratigraphy,
palaeobiogeography and palaeoecology.
Palaeogeography, Palaeoclimatology, Palaeoecology 409: 217–238
DOI: 10.1016/j.palaeo.2014.04.020
http://www.sciencedirect.com/science/article/pii/S003101821400217X

Highlights
This work is a comprehensive study in relation to the Maastrichtian of
Benguérir.
Selachians and reptiles show the same trends of diversity from L6 up to L2.
A lower and upper Maastrichtian association is highlighted.
A possible environmental signal affecting the predator community is noted.
The associations of Benguérir appear typical of the southern margin of
the Tethys.


Abstract
The Maastrichtian of Benguérir (eastern part of the Ganntour Basin,
Morocco) consists of about 20 m of phosphates displaying an alternance
of soft phosphate levels, marly horizons and hard phosphatic
limestones. Isolated teeth of selachians, actinopterygians and marine
reptiles are extremely numerous in these phosphatic deposits and have
been used for biostratigraphical, palaeodiversity and palaeoecological
purposes.

Detailed field work allowed to establish an exhaustive list of the
Benguérir marine vertebrate faunas with their biostratigraphical
distribution through five main fossiliferous levels (L6 to L2)
spanning all the Maastrichtian. Their importance for biochronological
purposes and correlations with other Maastrichtian phosphate deposits
worldwide appears noteworthy.

The selachians are currently represented by 60 species belonging to 32
genera and 7 orders. Among them, the genus Squalicorax is one of the
most interesting concerning high-resolution biostratigraphy and
correlations with other phosphate basins because of important rates of
change noted between the 5 species recovered from base (e.g.
occurrence of S. africanus) to top (e.g. strong representation of S.
pristodontus) of the Maastrichtian. The marine reptiles include mainly
mosasaurids but also scarcer plesiosaurs, chelonians and
crocodyliforms, representing at least 14 taxa. The mosasaurid
squamates are the most abundant and diversified with at least 8
species ranging all along the succession. The actinopterygians include
mainly teleosts but also pycnodonts, also common in all levels and
representing at least 7 taxa.

Selachians and reptiles show the same trends, in terms of species
richness per level, even if the reptiles are less informative due to a
less diversified assemblage. For sharks, L6 and L2 show a high
percentage of genera and species occurring only in the layer
concerned. The evolution of diversity in actinopterygian fishes is
less clear because of their low diversity. The use of dissimilarity
indices and agglomerative method underscores two distinct
associations: a lower one including the levels L6 and L5, and an upper
one comprising the levels L4 to L2. These two associations allow to
separate a lower and an upper Maastrichtian level and are important
for correlations all around the southern and eastern margins of the
Tethys. Another clear faunal turnover occurs between L3 and L2,
because of a high appearance rate in L2 (at least in sharks)
suggesting an increase in prey abundance, as testified by the rapid
increase of marine predator density.

Indeed, and through L6 to L2, a possible signal of an environmental
damage affecting the predator community can be noted by faunal
turnovers, even if no significant change in prey association was
clearly detected.

>From a palaeobiogeographical point of view, the faunal associations of
Benguérir appear typical of the southern and eastern margins of the
Tethys, with several typical species not occurring in the northern
Tethys.

==
Papers already posted on the DML but now available as free pdfs:

Mark T. Young, Lorna Steel, Martin P. Rigby, Eliza A. Howlett & Sylvia
Humphrey (2014)
Largest known specimen of the genus Dakosaurus (Metriorhynchidae:
Geosaurini) from the Kimmeridge Clay Formation (Late Jurassic) of
England, and an overview of Dakosaurus specimens discovered from this
formation (including reworked specimens from the Woburn Sands
Formation).
Historical Biology (advance online publication)
DOI:10.1080/08912963.2014.915822
Open access link:
http://www.tandfonline.com/doi/full/10.1080/08912963.2014.915822#.U5slJfldXTo

**

Qiyue Zhang, Wen Wen, Shixue Hu, Michael J. Benton, Changyong Zhou,
Tao Xie, Tao Lü, Jinyuan Huang, Brian Choo, Zhong-Qiang Chen, Jun Liu
& Qican Zhang (2014)
Nothosaur foraging tracks from the Middle Triassic of southwestern China.
Nature Communications 5, Article number: 3973
doi:10.1038/ncomms4973

Free pdf:
http://palaeo.gly.bris.ac.uk/Benton/reprints/2014nothosaur.pdf
==