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Ben Creisler | 23 May 2013 17:12
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Stegosaurus and Camptosaurus ecological segregation in Morrison Formation (free pdf)

From: Ben Creisler
bcreisler <at> gmail.com

A new open-access online paper:

J.R. Foster (2013)
Ecological Segregation of the Late Jurassic Stegosaurian and
Iguanodontian Dinosaurs of the Morrison Formation in North America:
Pronounced or Subtle?
PalArch’s Journal of Vertebrate Palaeontology 10(3): 1-11
ISSN 1567-2158
http://www.palarch.nl/2013/05/foster-j-r-2013-ecological-segregation-of-the-late-jurassic-stegosaurian-and-iguanodontian-dinosaurs-of-the-morrison-formation-in-north-america-pronounced-or-subtle-palarchs-jo/
Free pdf:
http://www.palarch.nl/wp-content/Foster-2013.pdf

The Upper Jurassic Morrison Formation of western North America has
yielded a number of specimens assigned to the ornithischian dinosaurs
Stegosaurus and Camptosaurus, and many of these specimens come from
channel sandstone deposits. Six new specimens are recorded mostly from
channel sandstones as well. Indeed, early analyses of site occurrences
(reducing the effects of large single-site samples) suggested that
Stegosaurus and Camptosaurus were more often found in channel
sandstone deposits than other common Morrison Formation dinosaurs such
as Camarasaurus or Diplodocus. This also indicated the possibility of
ecological segregation of the former two genera from other herbivorous
dinosaurs of the Morrison. Revisiting this question with additional
data suggests the pattern may not be as strong as it once appeared.
Analysis of occurrence data indicates that Stegosaurus and
Camptosaurus occur in channel sandstone deposits slightly more
frequently than the two sauropods, but statistical analysis of this
(Continue reading)

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Ben Creisler | 23 May 2013 16:46
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Yunmenglong, new sauropod from Early Cretaceous of China

From: Ben Creisler
bcreisler <at> gmail.com

A new online paper with a new sauropod Yunmenglong:

Junchang Lü, Li Xu, Hanyong Pu, Xingliao Zhang, Yiyang Zhang, Songhai
Jia, Huali Chang, Jiming Zhang & Xuefang Wei (2013)
A new sauropod dinosaur (Dinosauria, Sauropoda) from the late Early
Cretaceous of the Ruyang Basin (central China).
Cretaceous Research (advance online publication)
doi: http://dx.doi.org/10.1016/j.cretres.2013.04.009
http://www.sciencedirect.com/science/article/pii/S0195667113000839

A new long-necked sauropod dinosaur, Yunmenglong ruyangensis gen. et
sp. nov., is erected on the basis of an incomplete skeleton from the
late Early Cretaceous Haoling Formation of the Ruyang Basin, Henan
Province. The characters of the anterior cervical vertebrae, the shape
of the neural canal of the dorsal vertebra and the ball-shaped distal
end of the neural spine of caudal vertebrae with coarse surfaces
differ from other long-necked sauropod dinosaurs. The new genus has
characters in common with both Euhelopus and Erketu; it represents the
first long-necked sauropod dinosaur recorded from central China to
date. The rod-like, well-developed epipophyses and the pleurocoels on
the cervical vertebrae indicate that it may be close to Euhelopus, an
observation also confirmed by a phylogenetic analysis, which shows
that Erketu, Yunmenglong and Qiaowanlong form a clade, and are more
derived than Euhelopus.
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Ben Creisler | 23 May 2013 05:48
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Spheroolithid dinosaur eggs from Cretaceous of Zhejiang Province, China.

From: Ben Creisler
bcreisler <at> gmail.com

A new online paper:

Daniel E. Barta, Krista M. Brundridge, Jasmine A. Croghan, Frankie D.
Jackson, David J. Varricchio, Xingsheng Jin & Ashley W. Poust (2013)
Eggs and clutches of the Spheroolithidae from the Cretaceous Tiantai
basin, Zhejiang Province, China.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2013.792811
http://www.tandfonline.com/doi/full/10.1080/08912963.2013.792811#.UZ2Pf7W1FcQ

Numerous discoveries in the Tiantai basin of Zhejiang Province, China,
enrich our understanding of the parataxonomy, paleobiology and
taphonomic histories of fossil eggs from a diverse array of Cretaceous
oofamilies. We describe the most abundant of these egg types
catalogued in the Zhejiang Museum of Natural History, Spheroolithus
cf. zhangtoucaoensis (oofamily Spheroolithidae). Scanning electron
microscopy, here utilised for the first time on Spheroolithus eggs
from Tiantai, and petrographic microscopy reveal 0.81–1.37-mm thick
eggshell composed of a single structural layer of calcite with
slightly flaring shell units, irregular pores, horizontal accretion
lines and a sweeping extinction pattern under crossed polars. This
contradicts previous reports of the presence of two structural layers
in Tiantai Spheroolithus. Clutches consist of 2–13 eggs arranged in an
irregular, single-layered pattern. As these eggs are among the oldest
Asian examples of Spheroolithus currently known, they may shed light
on the early evolution of this oogenus. This study establishes the
definitive presence of the Spheroolithidae in the Tiantai basin,
(Continue reading)

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Ben Creisler | 23 May 2013 05:46
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Manidens (heterodontosaurid) teeth from Jurassic of Argentina

From: Ben Creisler
bcreisler <at> gmail.com

A new online paper:

Marcos G. Becerra, Diego Pola, Claudia A. Marsicano & Oliver W.M. Rauhut (2013)
The dentition of Manidens condorensis (Ornithischia;
Heterodontosauridae) from the Jurassic Cañadón Asfalto Formation of
Patagonia: morphology, heterodonty and the use of statistical methods
for identifying isolated teeth.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2013.794227
http://www.tandfonline.com/doi/full/10.1080/08912963.2013.794227#.UZ2Pm7W1FcQ

The recently described Manidens condorensis is one of the most
completely known taxa of the family Heterodontosauridae from the
southern landmasses. However, some dental aspects are not well known
due to preservational problems in the type material. This contribution
reports new isolated teeth found in the Cañadón Asfalto Formation
(Early-Middle Jurassic). These teeth are referred to Manidens
condorensis based on the presence of autapomorphic characters of the
unusual dentition of this taxon, such as the highly asymmetric tooth
crowns and small crenulations on each denticles. The isolated crowns
are well preserved and reveal the presence of undescribed and new
autapomorphical features, including apical and basal wear facets on
the occlusal surface of isolated crowns and a wear surface also in the
caniniform tooth. We carried out statistical analyses (including
morphogeometrical and discriminant analyses), using the holotype
crowns as a morphological starting point, for characterising shape
variation of the crowns along the toothrow and for identifying the
(Continue reading)

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Ben Creisler | 22 May 2013 17:57
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Gerrothorax (Triassic temnospondyl) growth (free pdf) and more non-dino papers

From: Ben Creisler
bcreisler <at> gmail.com

A number of new non-dino papers (plus a video) that may be interest:

S. Sanchez & R. R. Schoch (2013)
Bone Histology Reveals a High Environmental and Metabolic Plasticity
as a Successful Evolutionary Strategy in a Long-Lived Homeostatic
Triassic Temnospondyl.
Evolutionary Biology (advance online publication)
DOI: 10.1007/s11692-013-9238-3
http://link.springer.com/article/10.1007/s11692-013-9238-3
NOTE: pdf is open access (for now)

Evolutionary stasis (long-term stability of morphology in an evolving
lineage) is a pattern for which explanations are usually elusive. The
Triassic tetrapod Gerrothorax pulcherrimus, a gill-bearing
temnospondyl, survived for 35 million years in the Germanic Basin of
Central Europe persisting throughout the dinosaur-dominated Late
Triassic period. This evolutionary stasis coincides with the
occurrence of this species in a wide range of habitats and
environmental conditions. By the combination of palaeoecological and
palaeohistological analyses, we found great ecological flexibility in
G. pulcherrimus and present substantial evidence of developmental and
metabolic plasticity despite the morphological stasis. We conclude
that G. pulcherrimus could show the capacity to settle in water bodies
too harsh or unpredictable for most other tetrapods. This would have
been made possible by a unique life history strategy that involved a
wide reaction norm, permitting adjustment to fluctuating conditions
such as salinity and level of nutrients. Growth rate, duration of
(Continue reading)

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Ben Creisler | 22 May 2013 03:26
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Sigilmassasaurus (Theropoda) redescribed

From: Ben Creisler
bcreisler <at> gmail.com

A new online paper:

Bradley McFeeters, Michael J. Ryan, Sanja Hinic-Frlog & Claudia
Schröder-Adams (2013)
A reevaluation of Sigilmassasaurus brevicollis (Dinosauria) from the
Cretaceous of Morocco.
Canadian Journal of Earth Sciences (advance online publication)
doi: 10.1139/cjes-2012-0129
http://www.nrcresearchpress.com/doi/abs/10.1139/cjes-2012-0129#.UZwdrrW1FcQ

The original hypodigm of the controversial mid-Cretaceous Moroccan
dinosaur Sigilmassasaurus brevicollis is redescribed, and the
diagnosis of the taxon is revised. Unambiguously referred material is
restricted to cervical and anterior dorsal vertebrae sharing
apomorphies with the holotype. A newly recognized diagnostic character
of Sigilmassasaurus is the absence of anterior and posterior
interzygapophyseal laminae of the neural arch, so that the neural
spine directly meets the dorsal margin of the neural canal. A
phylogenetic analysis supports the inclusion of Sigilmassasaurus in
Tetanurae but not in Carcharodontosauridae. Sigilmassasaurus is
distinct from all other theropods known from comparable material and
is thus retained as a valid taxon.
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Ben Creisler | 21 May 2013 20:46
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Allosaurus head and neck function (free pdf)

From: Ben Creisler
bcreisler <at> gmail.com

New in open-access Palaeontologia Electronica:

Eric Snively, John R. Cotton, Ryan Ridgely, and Lawrence M. Witmer (2013)
Multibody dynamics model of head and neck function in Allosaurus
(Dinosauria, Theropoda).
Palaeontologia Electronica Vol. 16, Issue 2; 11A 29p
palaeo-electronica.org/content/2013/389-allosaurus-feeding
http://palaeo-electronica.org/content/2013/389-allosaurus-feeding

We present a multibody dynamics model of the feeding apparatus of the
large Jurassic theropod dinosaur Allosaurus that enables testing of
hypotheses about the animal's feeding behavior and about how
anatomical parameters influence function. We created CT- and
anatomical-inference-based models of bone, soft tissue, and air spaces
which we use to provide inertial properties for musculoskeletal
dynamics. Estimates of bone density have a surprisingly large effect
on head inertial properties, and trachea diameter strongly affects
moments of inertia of neck segments for dorsoventral movements. The
ventrally-placed insertion of m. longissimus capitis superficialis in
Allosaurus imparted over twice the ventroflexive accelerations of a
proxy control insertion lateral to the occipital condyle, the latter
being its position in nearly all other theropods. A feeding style that
involved defleshing a carcass by avian-raptor-like retraction of the
head in Allosaurus is more probable than is lateroflexive
shake-feeding, such as that seen in crocodilians and inferred for
tyrannosaurids.
(Continue reading)

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Ben Creisler | 20 May 2013 23:32
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Brain growth in Dysalotosaurus

From: Ben Creisler
bcreisler <at> gmail.com

A new online article:

S. Lautenschlager & T. Hübner (2013)
Ontogenetic trajectories in the ornithischian endocranium.
Journal of Evolutionary Biology (advance online publication)
DOI: 10.1111/jeb.12181
http://onlinelibrary.wiley.com/doi/10.1111/jeb.12181/abstract

Understanding ontogenetic and developmental patterns is critical for
reconstructing the life history of fossil vertebrates. In dinosaurs,
ontogenetic studies have nearly exclusively focused on changes in the
cranial and post-cranial skeleton, whereas ontogenetic changes in the
endocranium have received little attention. Here, we present digital
reconstructions of the brain and inner ear anatomy of two ontogenetic
stages of the Jurassic ornithischian dinosaur Dysalotosaurus
lettowvorbecki. Results show that the endocranial anatomy underwent
considerable changes during growth, including a rostrocaudal
elongation of the olfactory apparatus, a reduction in the cephalic and
pontine flexure and an increase in cerebellum size. Functional
elements, such as the cerebral hemispheres and the inner ear, were
already well developed in early ontogenetic stages, indicating a large
degree of precociality. The anisotropic pattern of size and shape
changes in the endocranium further indicates that ontogenetic
trajectories may be controlled by functional and environmental demands
in the different growth stages in Dysalotosaurus lettowvorbecki. The
occurrence of similar ontogenetic patterns in the endocranial anatomy
of derived ornithopod dinosaurs suggests a more widespread
(Continue reading)

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Tim Williams | 20 May 2013 05:58
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Kinematics of the Avian Wing and Shoulder during Ascending Flapping Flight and Uphill Flap-Running

David B. Baier. Stephen M. Gatesy, Kenneth P. Dial (2013)
Three-Dimensional, High-Resolution Skeletal Kinematics of the Avian
Wing and Shoulder during Ascending Flapping Flight and Uphill
Flap-Running.  PLOS ONE 8: e63982

Abstract:

"Past studies have shown that birds use their wings not only for
flight, but also when ascending steep inclines.
Uphill flaprunning or wing-assisted incline running (WAIR) is used by
both flight-incapable fledglings and flight-capable
adults to retreat to an elevated refuge. Despite the broadly varying
direction of travel during WAIR, level, and descending
flight, recent studies have found that the basic wing path remains
relatively invariant with reference to gravity. If so, joints
undergo disparate motions to maintain a consistent wing path during
those specific flapping modes. The underlying
skeletal motions, however, are masked by feathers and skin. To improve
our understanding of the form-functional
relationship of the skeletal apparatus and joint morphology with a
corresponding locomotor behavior, we used XROMM (Xray
Reconstruction of Moving Morphology) to quantify 3-D skeletal
kinematics in chukars (_Alectoris chukar_) during WAIR
(ascending with legs and wings) and ascending flight (AF, ascending
with wings only) along comparable trajectories.
Evidence here from the wing joints demonstrates that the glenohumeral
joint controls the vast majority of wing
movements. More distal joints are primarily involved in modifying wing
shape. All bones are in relatively similar orientations
at the top of upstroke during both behaviors, but then diverge through
(Continue reading)

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Ben Creisler | 19 May 2013 19:34
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Cricosaurus (Thalattosuchia) postcranial skeleton from Jurassic of Argentina

From: Ben Creisler
bcreisler <at> gmail.com

A new online paper:

Yanina Herrera, Marta S. Fernández & Zulma Gasparini (2013)
Postcranial skeleton of Cricosaurus araucanensis (Crocodyliformes:
Thalattosuchia): morphology and palaeobiological insights.
Alcheringa 37 (advance online publication) 1–14
DOI: 10.1080/03115518.2013.743709
http://www.tandfonline.com/doi/full/10.1080/03115518.2013.743709#.UZkLobW1FcQ

The metriorhynchid crocodyliform Cricosaurus araucanensis (Gasparini &
Dellapé) has been documented from Tithonian (Upper Jurassic) strata of
the Vaca Muerta Formation exposed in the Neuquén Basin, northwest
Patagonia, Argentina. Postcranial components of this species were
mentioned but not described in the original analysis. Subsequently,
other authors described the forelimbs. The postcranial elements of
metriorhynchids are poorly documented in comparison with their skulls,
but new data from C. araucanensis reveal delayed ossification of the
caudal neurocentral sutures indicating skeletal paedomorphosis
affecting not only the appendicular skeleton but also the posterior
region of the vertebral column. The morphology of the caudal region
(transverse processes of the first caudal vertebrae ventrally
deflected) and the reduction in the femur of the fourth trochanter
suggest a reduction of the hypaxial musculature allowing increased
epaxial musculature. This pattern of musculoskeletal arrangement is
consistent with the swimming style and propulsion by lateral
undulation of the tail, as proposed by previous authors.
(Continue reading)

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Ben Creisler | 19 May 2013 04:32
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Cymatosaurus(?) pistosauroid material from Triassic of Netherlands

From: Ben Creisler
bcreisler <at> gmail.com

A new online paper:

P. Martin Sander, Nicole Klein, Paul C. H. Albers, Constanze
Bickelmann & Herman Winkelhorst (2013)
Postcranial morphology of a basal Pistosauroidea (Sauropterygia) from
the Lower Muschelkalk of Winterswijk, The Netherlands.
Paläontologische Zeitschrift (advance online publication)
DOI: 10.1007/s12542-013-0181-5
http://link.springer.com/article/10.1007/s12542-013-0181-5

Two partial postcranial skeletons from the Lower Muschelkalk (early
Anisian) of Winterswijk, The Netherlands, are described in detail. The
specimens were assigned to basal Pistosauroidea, presumably to cf.
Cymatosaurus or a closely related taxon. Cymatosaurus is currently the
earliest member of the Pistosauroidea and is only known from skull
material. Taxonomical assignment is based on humerus morphology and
histology, and on morphological differences from other Sauropterygia
(Nothosauria and Pachypleurosauria).
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