Ben Creisler | 21 Nov 22:57 2014

Dinosaur and other tracks in new exhibit in Boulder, CO

Ben Creisler
bcreisler <at>

"Steps in Stone, Walking Through Time" exhibit at University of
Colorado Museum of Natural History focuses on trackway fossils
collected by paleontologist Martin Lockley

Companion website about fossil tracks

Ben Creisler | 21 Nov 19:34 2014

Saltillomimus, ornithomimid from Mexico + more news

Ben Creisler
bcreisler <at>

A number of recent news items:

Saltillomimus, ornithomimid from Coahuila region debuts in Mexico

News stories in Spanish about the formal public presentation of a
72-million-year-old ornithomimid named "Saltillomimus rapidus," based
on a partial articulated skeleton found along with a juvenile specimen
at Saltillo in Coahuila State in Mexico. It appears the formal
description has not been published yet, although a link to the
dissertation with the name is online.

Dissertation in English


Tom ("Tyrannosaurus") Holtz in New Zealand,  news coverage and radio interviews

(Continue reading)

Ben Creisler | 21 Nov 04:12 2014

Origin of feathers: genes predate Dinosauria (free pdf)

Ben Creisler
bcreisler <at>

A new online paper in MS form with free pdf.

Craig B. Lowe, Julia A. Clarke, Allan J. Baker, David Haussler, and
Scott V. Edwards (2014)
Feather development genes and associated regulatory innovation predate
the origin of Dinosauria.
Molecular Biology and Evolution (advance online publication)

The evolution of avian feathers have recently been illuminated by
fossils and the identification of genes involved in feather patterning
and morphogenesis.  However, molecular studies have focused mainly on
protein-coding genes. Using comparative genomics and more than 600,000
conserved regulatory elements, we show that patterns of genome
evolution in the vicinity of feather genes are consistent with a major
role for regulatory innovation in the evolution of feathers. Rates of
innovation at feather regulatory elements exhibit an extended period
of innovation with peaks in the ancestors of amniotes and archosaurs.
We estimate that 86% of such regulatory elements were present prior to
the origin of Dinosauria. On the branch leading to modern birds, we
detect a strong signal of regulatory innovation near IGFBP2 and
IGFBP5, which have roles in body size reduction, and may represent a
genomic signature for the miniaturization of dinosaurian body size
preceding the origin of flight.

News story:
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Ben Creisler | 20 Nov 22:43 2014

Psephoderma alpinum (Sauropterygia, Placodontia) from Late Triassic of Switzerland

Ben Creisler
bcreisler <at>

A new online paper:

James M. Neenan & Torsten M. Scheyer (2014)
New specimen of Psephoderma alpinum (Sauropterygia, Placodontia) from
the Late Triassic of Schesaplana Mountain, Graubünden, Switzerland.
Swiss Journal of Geosciences (advance online publication)
DOI: 10.1007/s00015-014-0173-9

Psephoderma alpinum is an armoured, durophagous placodont known from
the alpine Late Triassic. Here we present a new, well-preserved
isolated skull discovered in the Alplihorn Member (Late Norian–Early
Rhaetian) of the Kössen Formation, Schesaplana Mountain, which
straddles the Swiss/Austrian border. Micro-computed tomographic (µCT)
scanning was used to create an accurate osteological reconstruction of
the specimen, the first time this has been conducted for Psephoderma.
We thus clarify disputed anatomical features from previous
descriptions, such as a lack of a lacrimal and a pineal foramen that
is enclosed by the parietal. We also present the first description
based on µCT data of the lateral braincase wall, sphenoid region and
some cranial nerve canals for Psephoderma, with the location of the
hypophyseal seat, cerebral carotid foramina, dorsum sellae, prootic
foramen, lacrimal foramen, as well as all dental foramina being
described. This specimen represents the first skull of Psephoderma
recovered in Switzerland, and features such as poorly-sutured
braincase elements and its relatively small size compared to other
known specimens may indicate that it was a sub-adult.
(Continue reading)

Ben Creisler | 20 Nov 18:37 2014

Dinosaur coprolites from Late Cretaceous of India indicate omnivory

Ben Creisler
bcreisler <at>

A new online paper:

Ashu Khosla, Karen Chin, Habib Alimohammadin & Debi Dutta (2014)
Ostracods, plant tissues, and other inclusions in coprolites from the
Late Cretaceous Lameta Formation at Pisdura, India: Taphonomical and
palaeoecological implications.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)


First record of ostracods in Upper Cretaceous coprolites from Pisdura, India.

Aquatic inclusions include diatoms, a charophyte, chrysophytes and
sponge spicules.

Faecal inclusions and phosphate content suggest intentional or
inadvertent omnivory.

The depositional setting indicates fluvio-lacustrine conditions.


A rich microbiota with distinctive plant fossils has been discovered
in Type A morphotype coprolites from the Lameta Formation of Pisdura,
in Maharashtra, India. Macerated fractions examined with scanning
(Continue reading)

Ben Creisler | 20 Nov 18:31 2014

Libonectes (elasmosaurid plesiosaur) re-examined

Ben Creisler
bcreisler <at>

A new online paper:

Sven Sachs & Benjamin P. Kear (2014)
Postcranium of the paradigm elasmosaurid plesiosaurian Libonectes
morgani (Welles, 1949).
Geological Magazine (advanced online publication)

Elasmosauridae constitutes one of the most immediately recognizable
plesiosaurian radiations. Their distinctive body plan represents the
popular model for Plesiosauria, and is typified by an osteological
morphology especially adapted for hyper-elongation of the neck.
Nevertheless, many archetypal elasmosaurids are known only from
incomplete and/or inadequately documented material, a problem that has
contributed to their uncertain intra-clade relationships. A prime
example of this is Libonectes morgani from the Upper Cretaceous of
Texas, USA, which is frequently presented as an elasmosaurid
structural proxy because of its three-dimensionally preserved holotype
skull. Perplexingly though, both the taxonomic diagnosis and
phylogenetic placement of L. morgani rely primarily upon the cervical
vertebrae, together with the pectoral girdle and forelimb, yet most of
these elements are now lost and figured only as line drawings. We
therefore reviewed the remnant postcranial skeleton of L. morgani
first-hand with the objective of clarifying its defining character
states. Our observations showed that the existing diagnosis of L.
morgani is indeed inadequate. Moreover, the only identifiable
(Continue reading)

Ben Creisler | 20 Nov 18:28 2014

New dinosaur-bearing site from Upper Triassic of Brazil

Ben Creisler
bcreisler <at>

A new online paper:

Rodrigo Temp Müller, Átila Augusto Stock da Rosa, Lúcio Roberto da
Silva, Alex Sandro Schiller Aires, Cristian Pereira Pacheco, Ane Elise
Branco Pavanatto & Sérgio Dias-da-Silva (2014)
Wachholz, A new exquisite dinosaur-bearing fossiliferous site from the
Upper Triassic of southern Brazil.
Journal of South American Earth Sciences (advance online publication)


We describe a new dinosaur-bearing fossiliferous site from the
Caturrita Formation.

It yielded complete and exceptionally well-preserved dinosaurs.

This is remarkable due to the worldwide scarcity of complete early
Norian dinosaurs.

The new site comprises at least four sauropodomorphs.

In addition, a new taxonomic record is proposed based on an
archosauriform tooth.

(Continue reading)

Ben Creisler | 20 Nov 01:11 2014

Pterosaur respiration article and cover art

Ben Creisler
bcreisler <at>

An article first published online in 2013, now officially out as cover
story for December Anatomical Record:

Nicholas R. Geist, Willem J. Hillenius, Eberhard Frey, Terry D. Jones
and Ross A. Elgin (2014)
Breathing in a box: Constraints on lung ventilation in giant pterosaurs.
Anatomical Record 297(12): 2233–2253
DOI: 10.1002/ar.22839

Pterosaurs were the first vertebrates to achieve active flight, with
some derived forms reaching enormous size. Accumulating fossil
evidence confirms earlier indications that selection for large size in
these flying forms resulted in a light, yet strong skeleton
characterized by fusion of many bones of the trunk. However, this
process also added mechanical constraints on the mobility of the
thorax of large pterosaurs that likely limited the options available
for lung ventilation. We present an alternative hypothesis to recent
suggestions of an avian-like mechanism of costosternal pumping as the
primary means of aspiration. An analysis of the joints among the
vertebrae, ribs, sternum, and pectoral girdle of large pterosaurs
indicates limited mobility of the ribcage and sternum. Comparisons
with modes of lung ventilation in extant amniotes suggests that the
stiffened thorax, coupled with mobile gastralia and prepubic bones,
may be most consistent with an extracostal mechanism for lung
ventilation in large pterodactyloids, perhaps similar to a
crocodile-like visceral displacement system.
(Continue reading)

Ben Creisler | 19 Nov 21:42 2014
Ben Creisler | 19 Nov 21:01 2014

Hesperornis osteohistology compared to penguins (free pdf)

Ben Creisler
bcreisler <at>

A new paper in open access:

Laura E. Wilson & Karen Chin (2014)
Comparative osteohistology of Hesperornis with reference to pygoscelid
penguins: the effects of climate and behaviour on avian bone
Royal Society Open Science 1: 140245

The broad biogeographic distribution of Hesperornis fossils in Late
Cretaceous Western Interior Seaway deposits has prompted questions
about whether they endured polar winters or migrated between mid- and
high latitudes. Here, we compare microstructures of hesperornithiform
long bones from Kansas and the Arctic to investigate whether migration
or Late Cretaceous polar climate affected bone growth. We also examine
modern penguin bones to determine how migration and climate may
influence bone growth in birds with known behaviours. Histological
analysis of hesperornithiform samples reveals continuous bone
deposition throughout the cortex, plus an outer circumferential layer
in adults. No cyclic growth marks, zonation or differences in
vasculature are apparent in the Hesperornis specimens. Comparatively,
migratory Adélie and chinstrap penguin bones show no zonation or
changes in microstructure, suggesting that migration is not
necessarily recorded in avian bone microstructure. Non-migratory
gentoos show evidence of rapid bone growth possibly associated with
increased chick growth rates in high-latitude populations and large
(Continue reading)

Ben Creisler | 19 Nov 18:46 2014

Triassic marine reptiles from China: Kwangsisaurus date & Chaohusaurus environment

Ben Creisler
bcreisler <at>

Two recent papers with free pdfs about Triassic marine reptiles from
China. Main texts are in Chinese.

SHANG Qing-Hua, LIU Jun, XU Guang-Hui & WANG Li-Ting (2014)
The age of Triassic marine reptile Kwangsisaurus orientalis
(Sauropterygia) from Wuming, Guangxi, China.
Vertebrata PalAsiatica 52(4):  381-389
free pdf:

The holotype of Kwangsisaurus orientalis Young, 1959 is the only
Triassic marine  reptile specimen known from Guangxi Zhuang Autonomous
Region in southern China. This  fossil was collected from Wuming
County in 1950s. The exact provenance of the specimen is  unclear, but
it has long been regarded as an Early Triassic sauropterygian
following Young’s  original description (Li, 2006b; Li et al., 2008;
Zhao et al., 2008). The uncertainty regarding  its age has introduced
confusion into the studies of biogeography and evolutionary history of
 Chinese Triassic sauropterygians. Based on recent field work and the
help of several local geologists who have knowledge  of the specimen’s
history, we have determined that the holotype of K. orientalis was
from a  quarry situated 2 km southeast of Fupeng, Suliang Village,
Xianhu Township, Wuming County  (Fig. 1). The type specimen was
obtained from a fossiliferous bed within thin-bedded marlite,  which
is considered as the lower part of the Banna Formation based on
lithological features.  This fossiliferous bed contains abundant
ammonites such as Balatonites, Protrachyceras, and  Leiophyllites, in
(Continue reading)