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The House of the New Papers

Horner, J.R., and Goodwin, M.B. 2009. Extreme cranial ontogeny in the Upper
Cretaceous dinosaur Pachycephalosaurus. PLoS ONE 4(10):e7626 (1-11). doi:

ABSTRACT: Background

Extended neoteny and late stage allometric growth increase morphological
disparity between growth stages in at least some dinosaurs. Coupled with
relatively low dinosaur density in the Upper Cretaceous of North America,
ontogenetic transformational representatives are often difficult to
distinguish. For example, many hadrosaurids previously reported to represent
relatively small lambeosaurine species were demonstrated to be juveniles of
the larger taxa. Marginocephalians (pachycephalosaurids + ceratopsids)
undergo comparable and extreme cranial morphological change during ontogeny.

Methodology/Principal Findings

Cranial histology, morphology and computer tomography reveal patterns of
internal skull development that show the purported diagnostic characters for
the pachycephalosaurids Dracorex hogwartsia and Stygimoloch spinifer are
ontogenetically derived features. Coronal histological sections of the
frontoparietal dome of an adult Pachycephalosaurus wyomingensis reveal a
dense structure composed of metaplastic bone with a variety of extremely
fibrous and acellular tissue. Coronal histological sections and computer
tomography of a skull and frontoparietal dome of Stygimoloch spinifer reveal
an open intrafrontal suture indicative of a subadult stage of development.
These dinosaurs employed metaplasia to rapidly grow and change the size and
shape of their horns, cranial ornaments and frontoparietal domes, resulting
in extreme cranial alterations during late stages of growth. We propose that
Dracorex hogwartsia, Stygimoloch spinifer and Pachycephalosaurus
wyomingensis are the same taxon and represent an ontogenetic series united
by shared morphology and increasing skull length.


Dracorex hogwartsia (juvenile) and Stygimoloch spinifer (subadult) are
reinterpreted as younger growth stages of Pachycephalosaurus wyomingensis
(adult). This synonymy reduces the number of pachycephalosaurid taxa from
the Upper Cretaceous of North America and demonstrates the importance of
cranial ontogeny in evaluating dinosaur diversity and taxonomy. These growth
stages reflect a continuum rather than specific developmental steps defined
by ?known? terminal morphologies.

Rivera-Sylva, H.E., Frey, E., Palomino-Sánchez, F.J., Guzman-Gutiérrez,
J.R., and Ortiz-Mendieta, J.A. 2009. Preliminary report on a Late Cretaceous
vertebrate fossil assemblage in northwestern Coahuila, Mexico. Boletín de la
Sociedad Geológica Mexicana 61(2):239-244.

ABSTRACT: A new vertebrate fossil assemblage of Late Cretaceous age is
reported here. This discovery represents the results of the 2007 and 2008
field seasons in the locality known as ?Las Jicoteas? situated in the
municipality of Ocampo, in northwestern Coahuila, Mexico.
The stratigraphic sequence where this fossil fauna occurs can be correlated
to the Lower Member of the continental Aguja Formation that outcrops in the
neighbouring Big Bend region of Texas.
This new fauna bears the first record of a nodosaur for Mexico, and, also
additional dinosaur remains attributed to the families Tyrannosauridae and
Hadrosauridae are recorded. Associated fossil taxa include lepisosteid
fishes, turtles and crocodile remains. 
     The palaeocological conditions inferred by this new faunal assemblage
suggest a paralic system with prodelta, marshes, lagoons, and nearshore
marine deposits.

Muttoni, G., Kent, D.V., Jadoul, F., Olsen, P.E., Rigo, M., Galli, M.T., and
Nicora, A. 2009. Rhaetian magneto-biostratigraphy from the Southern Alps
(Italy): Constraints on Triassic chronology. Palaeogeography,
Palaeoclimatology, Palaeoecology. doi: 10.1016/j.palaeo.2009.10.014.

ABSTRACT: New Late Triassic-earliest Jurassic magneto-biostratigraphic data
have been obtained from three overlapping sections in the Southern Alps,
Italy (Costa Imagna, Brumano, Italcementi Quarry), comprised of ~ 520 m of
shallow marine carbonates outcropping in stratigraphic continuity.
Characteristic magnetic components of presumed depositional age record a
sequence of 9 normal and reverse polarity magnetozones (as defined by at
least three stratigraphically superposed samples) linked by conodont and
palynofloral evidence from this study and the literature to Rhaetian to
Triassic?Jurassic boundary age. This represents a significantly larger
number of polarity zones than previously recognized in more condensed
Rhaetian sections from the literature, and by inference represents more
time. These data are placed in a broader Late Triassic temporal framework by
means of correlations to published magneto-biostratigraphic data from the
Tethyan marine Pizzo Mondello section and the Newark astronomical polarity
time scale (APTS). This framework is consistent with a position of the
Norian?Rhaetian boundary (as defined at Brumano and Pizzo Mondello by the
first appearance of Misikella posthernsteini) within Newark magnetozones
E17r?E19r in the ~ 207?210 Ma time interval, in basic agreement with the
position originally estimated in the Newark using pollen biostratigraphy
(E18 at 208?209 Ma). This framework is also consistent with the position of
the Triassic?Jurassic boundary interval (placed at Italcementi Quarry at the
acme of Kraeuselisporites reissingeri coincident with a negative carbon
isotope excursion) correlative to just above Newark magnetozone E23r and
just below the oldest CAMP lavas dated at ~ 202 Ma. Hence, we estimate the
duration of the Rhaetian to be ~ 5.5?8.5 Myr (or even longer if the
Triassic?Jurassic boundary is instead placed above the negative carbon
isotope excursion as at Kuhjoch, which is the designated GSSP for the base
of the Hettangian), and encompassing 9 magnetozones. This duration contrasts
with a duration of ~ 2 Myr and only ~ 4 magnetozones in several alternative
published magneto-biostratigraphic schemes.

Martin, J.E., and Delfino, M. 2009. Recent advances on the comprehension of
the biogeography of Cretaceous European eusuchians. Palaeogeography,
Palaeoclimatology, Palaeoecology. doi: 10.1016/j.palaeo.2009.10.021.

ABSTRACT: Within the last two decades, a growing interest has emerged with
the aim of understanding the structure of the paleocommunities from
Cretaceous continental deposits of Europe. Conspicuous research efforts have
concentrated on outcrops from Northern Spain, Southern France, Italy, and
Romania. Of special relevance are the researches in Romanian outcrops
because they considerably extend the sampling eastward, providing a wide
geographical scope in faunal comparisons across the Cretaceous European
archipelago. Excavations have yielded previously unknown vertebrates,
including members of Crocodilia. Most Late Cretaceous eusuchians reported so
far have been from North America with a few European exceptions:
Hylaeochampsa vectiana Owen, Bernissartia fagesii Dollo, Allodaposuchus
precedens Nopcsa from Valioara, Romania, and ?Crocodilus? affuvelensis
Matheron. Here, the fossil record of European eusuchians is reviewed and
peculiarities of the emergence of Eusuchia in Europe are discussed in light
of the faunal turnover that occurred between the Early and Late Cretaceous.
Additionally to biomechanical novelties tied to evolutionary landmarks
marking the transition between advanced neosuchians to eusuchians, other
possible factors are put forward and discussed. As such, climatic conditions
and paleogeographic settings may have permitted faunal exchanges between
North America and Europe, as suggested by the study of other vertebrates.
Further, the present review provides a basis for a comparison with other
Laurasian and Gondwanan faunas of the Cretaceous.

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

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