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New Mesozoic vertebrate (non-dinosaur) papers



From: Ben Creisler
bh480@scn.org

Some recent papers about non-dinosaurian (mosty) Mesozoic vertebrates:

Daniela Schwarz-Wings, Nicole Klein, Christian Neumann, & Udo Resch (2011)
A new partial skeleton of Alligatorellus (Crocodyliformes) associated with
echinoids from the Late Jurassic (Tithonian) lithographic limestone of
Kelheim, S-Germany.
Fossil Record 14(2):195?205
DOI: 10.1002/mmng.201100007
http://onlinelibrary.wiley.com/doi/10.1002/mmng.201100007/abstract

Abstract
A slab from the Late Jurassic (Early Tithonian) lithographic limestone
exhibiting skeletal material of an atoposaurid crocodyliform associated
with four echinoids from the vicinity of Kelheim (S-Germany) is described.
The atoposaurid is represented by a row of dorsal paravertebral osteoderms,
caudal osteoderms, a caudal vertebra and haemapophyses, dorsal ribs, and
parts of the right fore- and hindlimb. Some of the bones have been prepared
out of the slab and most of them are preserved three-dimensionally, which
is in contrast to the general much flattened preservation of atoposaurid
skeletons. This well preserved specimen allows one of the most detailed
descriptions of an atoposaurid limb skeleton so far, yielding in particular
well preserved manual elements. By comparison with all other known
atoposaurid taxa, the specimen can be determined to belong to the genus
Alligatorellus based on an identical morphology of osteoderms. In contrast,
a high ontogenetic variety and missing data make comparisons of limb ratios
in different atoposaurids virtually useless for taxonomy. Femoral and
tibial lengths suggest that this specimen is the largest atoposaurid known
from the Solnhofen-Eichsttt region. It is suggested that the crocodyliform
carcass has been washed into the lagoon and was subsequently embedded
together with the tests of four holectypoid echinoids, which probably
populated the lagoon. 
====

Ji Cheng ; Jiang Dayong; Hao Weicheng; Sun Yuanlin; Sun Zuoyu  (2011)
True Tailbend Occurred in the Late Triassic: Evidence from Ichthyosaur
Skeletons of South China.  
Acta Scientiarum Naturalium Universitatis Pekinensis  47(2) 309-314  
http://xbna.pku.edu.cn/en/view.xbna?id=2498
Abstract: 
Here the true tailbends are reported in two complete skeletons of
Guanlingsaurus from the LateTtriassic of Guizhou Province, southwestern
China after accurate observations, measurements and comparisons with
Ichthyosaur ofEarly Jurassic. They have acquired the wedge-shaped centra
and the angles in these tailbends are around 15[degree] while those in
jurassic types are around 60[degree]. This study shows for the first time
that wedge-shaped tailbend centra already existed in merriamosaurs as early
as Late Triassic time, probably being a result of coevolution between
ichthyosaurs and the environment. The occurrence of the true tailbend
connected Triassic and Jurassic ichthyosaurs that used to be considered as
separate groups in previous literature. The present finding also suggests
the monophyly of ichthyopterygia. 

---
S.P. Bennett , P.M. Barrett , M.E. Collinson, S. Moore-Fay, P.G. Davis, 
and C.P. Palmer (2011)
A new specimen of Ichthyosaurus communis from Dorset, UK, and its bearing
on the stratigraphical range of the species. 
Proceedings of the Geologists' Association (advance online publication)
doi:10.1016/j.pgeola.2011.07.001
http://www.sciencedirect.com/science/article/pii/S0016787811000678
Abstract
This paper describes a new ichthyosaur specimen from the Stonebarrow Marls
Member (Charmouth Mudstone Formation) of Charmouth, Dorset. It is
substantially complete and various characters of the skull (snout ratios
and basioccipital morphology) and appendicular skeleton (the number of
digits on the hind paddle, which can be used to infer the number of digits
on the front paddle) indicate that the specimen is referable to
Ichthyosaurus communis. This provides the first direct evidence for the
presence of I. communis in the Pliensbachian, extending the stratigraphic
range of the species. The specimen also preserves a probable gullet
content, which demonstrates that fish formed part of the diet of this
individual.

===
A. A. Kurkin (2011)
Permian anomodonts: Paleobiogeography and distribution of the group. 
Paleontological Journal  45(4): 432-444, 
DOI: 10.1134/S0031030111030075 
http://www.springerlink.com/content/yn10593m38660653/

In the Late Permian, higher anomodonts, dicynodonts, reached an almost
global distribution. The wide distribution makes this group an important
tool in Upper Permian biostratigraphy. Three paleobiogeographic hypotheses
for the center of the origin and migration pathways of the major anomodont
groups are analyzed. Remains of these animals are most abundant in South
Africa; however, they are also widespread in Eastern Europe, China, and
India; interesting materials come from Western Europe, Madagascar, Central
Africa, and South America. Biogeographic distribution of anomodonts
supports the hypothesis of two stages in the origin and distribution of
anomodonts. At the first stage, primitive anomodonts evolved in the
Northern and Southern Hemispheres, forming high-rank endemic groups. At the
second stage, dicynodonts, which appeared in the Southern Hemisphere,
evolved rapidly; some groups inhabiting equatorial regions gave rise to the
second wave of adaptive radiation, with the emergence of oudenodontids and
dicynodontids, which secondarily adapted to high latitudes of the Southern
Hemisphere, penetrated into the Northern Hemisphere, and formed there new
endemic groups of subfamily rank.
===

Rainer R. Schoch (2011)
A trematosauroid temnospondyl from the Middle Triassic of Jordan.
Fossil Record 14(2):119?127
DOI: 10.1002/mmng.201100002
http://onlinelibrary.wiley.com/doi/10.1002/mmng.201100007/abstract

Abstract
A well-preserved mandible from the Lower Anisian Mukheiris Formation from
near the Dead Sea (Jordan) proves the presence of tetrapods in the region.
It is identified as a stereospondyl lower jaw sharing synapomorphies with
the Trematosauroidea. It has the following combination of features: (1)
Meckelian fenestra almost one-third the length of the ramus, (2)
postglenoid area posterodorsally rising and robust, as long as glenoid
facet, (3) preglenoid process substantially higher than medial margin of
adductor chamber, (4) all teeth anteriorly and posteriorly carinate, and
(5) symphysis without additional tooth rows, with a pair of unequal fangs
as part of the dentary arcade, which contains unusually large teeth. The
Jordan specimen shares most character-states with South African
Microposaurus (size of teeth, bicarinate structure) and the Russian
Inflectosaurus (preglenoid process, PGA). Phylogenetic analysis finds it to
nest with Microposaurus, whereas Inflectosaurus forms an unresolved
polytomy with other trematosauroids.



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