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First New Dino of 2010



.and some other new papers:


Longrich, N.R., Sankey, J., and Tanke, D. 2010. Texacephale langstoni, a new
genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper
Campanian Aguja Formation, southern Texas, USA. Cretaceous Research. doi:
10.1016/j.cretres.2009.12.002.

ABSTRACT: Recent work in the Campanian Aguja Formation of Big Bend, Texas,
has resulted in the recovery of two frontoparietal domes from a new genus of
pachycephalosaur. Texacephale langstoni gen. et sp. nov. is diagnosed by a a
tall, arched nasal boss, flange-like processes articulating the dome with
the peripheral elements, and a low pedicel separating the cerebral fossa
from the skull roof. The skull dome is composed largely of the fused
frontals and parietals, with limited participation of the peripheral
elements, and the supratemporal fenestrae remain open. Phylogenetic analysis
indicates that Texacephale langstoni is a basal member of the
Pachycephalosauria. The discovery of Texacephale supports previous
suggestions that the dinosaur fauna of Texas was distinct from that of
contemporary assemblages to the north. The phylogenetic analysis presented
here indicates that the Asian pachycephalosaurs form a monophyletic group,
deeply nested within the Pachycephalosauridae, and that the basal members of
the group are all North American. This finding indicates that
pachycephalosaurids originated in North America, rather than Asia, as
previously believed. The high diversity of North American pachycephalosaurs
and the late appearance of pachycephalosaurs in Asia are consistent with
this hypothesis. The biology of Texacephale and other Pachycephalosauridae
are also discussed. The morphology of the dome in Texacephale and other
pachycephalosaurs supports the hypothesis that pachycephalosaurids engaged
in intraspecific combat, while the occurrence of Texacephale and other
pachycephalosaurs in nearshore deposits argues that the pachycephalosaurs
were not restricted to inland habitats.





Fricke, H.C., Foreman, B.Z., and Sewall, J.O. 2010. Integrated climate
model-oxygen isotope evidence for a North American monsoon during the Late
Cretaceous. Earth and Planetary Science Letters 289(1-2):11-21. doi:
10.1016/j.epsl.2009.10.018.

ABSTRACT: During the Late Cretaceous, western North America was
characterized by a close geographic association between the Sevier highlands
and the Western Interior Seaway. In this paper, an atmospheric general
circulation model (AGCM) is used to simulate the impact of this geographic
association on surface pressure, wind direction, and precipitation, and it
is predicted that seasonal changes in these variables resulted in a strong
monsoon along the eastern flank of the Sevier Highlands. Confirmation that
these model simulations are accurate is provided by isotopic data from
foreland basin sediments. In particular oxygen isotope records from
different environments (large rivers, small streams and ponds) and proxies
(unionid bivalve shells and paleosol carbonates) indicate that foreland
basin streams were recharged by local precipitation with high oxygen isotope
ratios while large trunk rivers were recharged by high-elevation
precipitation. This hydrologic pattern is observed from Alberta to Utah and
is consistent with east to west monsoonal air mass movements and associated
seasonal rainfall. Recognition of a highland-driven monsoon has implication
in regard to studies of fossil taphonomy, of water vapor transport, and of
links between climate and mountain uplift and exhumation in this region.





Pryon, R.A. 2010. A likelihood method for assessing molecular divergence
times and the placement of fossil calibration. Systematic Biology. doi:
10.1093/sysbio/syp090.

ABSTRACT: Estimating divergence times using molecular sequence data has
become a common application of statistical phylogenetics. However,
disparities between estimated ages for clades produced in different studies
have become equally commonplace. Here, I propose a method for the objective
assessment of the likelihood of inferred divergence times to evaluate the
placement of fossil constraints using information from the broader fossil
record. The inclusion of nodes from the Tree of Life for which credible age
ranges are known, in addition to the fossil constraints used in the ingroup,
will allow for the comparison of alternate fossil placements when the
phylogenetic affinity of a fossil is ambiguous as well as provide a
heuristic assessment of the global likelihood of estimated divergence times.
The use of these "likelihood checkpoints" will allow for the comparison of
inferred dates across data sets and across taxonomic groups to place
divergence time estimates into a broader evolutionary timescale. The method
is illustrated with an example using an expanded phylogenetic estimate of
the Gnathostomata, inferred with relaxed-clock molecular dating methods.






Rieppel, O. 2010. Species monophyly. Journal of Zoological Systematics and
Evolutionary Research 48(1):1-8. doi: 10.1111/j.1439-0469.2009.00545.x.

ABSTRACT: In biological systematics, as well as in the philosophy of
biology, species and higher taxa are individuated through their unique
evolutionary origin. This is taken by some authors to mean that monophyly is
a (relational) property not only of higher taxa, but also of species. A
species is said to originate through speciation, and to go extinct when it
splits into two daughter species (or through terminal extinction). Its
unique evolutionary origin is said to bestow identity on a species through
time and change, and to render species names rigid designators. Species
names are thus believed to function just like names of supraspecific taxa.
However, large parts of the Web of Life are composed of species that do not
have a unique evolutionary origin from a single population, lineage or
stem-species. Further, monophyly is an ambiguous concept if it is defined
simply in terms of 'unique evolutionary origin'. Disambiguating the concept
by defining a monophyletic taxon as 'a taxon that includes the ancestor and
all, and only, its descendant' renders monophyly inapplicable to species. At
the heart of the problem lies a fundamental distinction between species and
monophyletic taxa, where species form mutually exclusive reticulated
systems, while higher taxa form inclusive hierarchical systems. Examples are
given both at the species level and below to illustrate the problems that
result from the application of the monophyly criterion to species. The
conclusion is that the concepts of exclusivity and monophyly should be
treated as non-overlapping: exclusivity marks out a species
synchronistically, i.e. in the present time. Monophyly marks out clades
(groups of species) diachronistically, i.e. within an historical dimension.







~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jerry D. Harris
Director of Paleontology
Dixie State College
Science Building
225 South 700 East
St. George, UT  84770   USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
 and     dinogami@gmail.com
http://cactus.dixie.edu/jharris/


"I have noticed even people who
claim everything is predestined, and
that we can do nothing to change it,
look before they cross the road."

                   -- Stephen Hawking

"Prediction is very difficult,
especially of the future."

                   -- Niels Bohr