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Many New Papers
Some still new from '05; others brand-spankin' new!
Karl, H.-V., and G. Tichy. 2005. About the first occurrence of pseudosuchian
body remains (Archosauria: Rauisuchidae) from the Lower to Middle Triassic
Chirotherian-Sandstone of Thuringia (SE Germany). Studia Geologica
ABSTRACT: Moulds of osteoderms from a pseudosuchian reptile are described
from the Lower to Lower Middle Triassic Thuringian Chirotherian Sandstone of
Thuringia (SE Germany) and compared with the Anisian reptile _Ticinosuchus_.
One of the imprints shows clear affinities to this rauisuchid genus.
Averianov, A. O., T. Martin, S. E. Evans, and A. A. Bakirov. 2006. First
Jurassic Choristodera from Asia. Naturwissenschaften 93(1):46-50. doi:
ABSTRACT: Although choristoderes have a good Lower Cretaceous record in
Asia, they have never previously been recorded from Jurassic deposits. Here
we describe fragmentary vertebral material referable to Choristodera indet.
from the Middle Jurassic Balabansai Svita of the Fergana Valley, Kyrgyzstan.
This provides a significant range extension for the group in Asia and shows
that choristoderes already had a Pan-Laurasian distribution in the Jurassic.
Lü, J., Y. Kobayashi, C. Yuan, S. Ji, and Q. Ji. 2005. SEM observation of
the wing membrane of _Beipiaopterus chenianus_ (Pterosauria). Acta Geologica
Sinica (English Edition) 79(6):766-769.
ABSTRACT: The cross-section and surface structures of wing membranes from
the ctenochasmatid pterosaur _Beipiaopterus chenianus_ were observed through
a scanning electron microscope (SEM). The results show that the wing
membrane contains a high density of blood vessels, implying strong
thermoregulatory function, similar to that of a bat.
Schulte, P., R. Speijer, H. Mai, and A. Kontny. 2006. The
Cretaceous-Paleogene (K-P) boundary at Brazos, Texas: sequence stratigraphy,
depositional events and the Chicxulub impact. Sedimentary Geology
184(1-2):77-109. doi: 10.1016/j.sedgeo.2005.09.021.
ABSTRACT: Two cores from Brazos, Texas, spanning the Cretaceous-Paleogene
(K-P) boundary, are investigated by a multidisciplinary approach aiming at
unraveling environmental changes and sequence stratigraphic setting. In
addition, the sedimentology of the K-P event deposit and its correlation
with the K-P boundary is studied. Foraminifera and nannofossil stratigraphy
indicates that both cores include a latest Maastrichtian (Zone CF1-CF2) and
earliest Danian (P0, Pa and P1a) shale sequence with a sandy and Chicxulub
ejecta-bearing event deposit at the K-P boundary; a hiatus of unknown
duration may be present by the unconformable base of the event deposit.
Planktic foraminifera as well as calcareous nannofossil abundance and
diversity both decline abruptly above the event deposit (K-P mass
extinction), whereas benthic foraminifera show a pronounced faunal change
but no mass extinction.
Mineralogical and geochemical proxies suggest that-except for the
sandwiched K-P event deposit-no facies change took place across the K-P
boundary and no evidence for adverse an- or dysoxic sedimentary conditions
following the Chicxulub impact was observed. Therefore, the interval
bracketing the K-P event deposit is considered as highstand systems tract.
Increased coarse detritus input and low planktic/benthic (P/B) foraminifera
ratios during the earliest Paleocene (P0 and Pa) both suggest an increased
coastal proximity or relative sea-level lowering, although the K-P mass
extinction of planktic foraminifera might have influenced the P/B ratios as
well. Consequently, the sandy shales of the early Paleocene are considered
as late regressive highstand or as lowstand deposit. During P1a, shales
assigned as transgressive systems tract overlie a pyrite- and
glauconite-rich bioturbated transgressive surface or type-2-sequence
boundary. The smectite-dominated clay assemblage, with minor illite,
kaolinite and chlorite indicates semiarid-humid climates with no obvious
shifts across the K-P boundary. The magnetic susceptibility signature during
the Maastrichtian reveals a subtle cyclic (or rhythmic) pattern, whereas a
high-amplitude cyclic pattern is present during the early Danian.
The K-P event deposit shows a succession of high-energetic debris flows
and turbidites derived from multiple source areas, followed by a period of
decreasing current energy. Deposition was likely triggered by multiple
tsunami or tempestites followed by a prolonged period of reworking and
settling. The Chicxulub ejecta at the base of the K-P event deposit consists
of Mg-rich smectite-as well as Fe-Mg-rich chlorite-spherules. Their
mineralogical composition points to target rocks of mafic to intermediate
composition, presumably situated in the northwestern sector of the Chicxulub
impact structure. Besides these silicic phases, the most prominent ejecta
components are limestone clasts, accretionary carbonate clasts, and
microspar, suggesting that the Texas area received ejecta also from shallow,
carbonate-rich lithologies at the impact site on the Yucatán carbonate
platform. The excellent correlation of Chicxulub ejecta at Brazos with
ejecta found in the K-P boundary layer worldwide - along with the associated
mass extinction - provides no evidence that Chicxulub predated the K-P
boundary and allows for unequivocal positioning of the K-P boundary at the
Ciampaglio, C. N., G. A. Wray, and B. H. Corliss. 2005. A toothy tale of
evolution: convergence in tooth morphology among marine Mesozoic-Cenozoic
sharks, reptiles, and mammals. The Sedimentary Record 3(4):4-8.
ABSTRACT: Although mechanisms of niche replacement are discussed thoroughly
in the evolutionary paleontological literature (i.e., extinctions,
competition, evolution of new adaptive morphologies), actual studies
involving quantitative analyses are not common. In this study, morphological
features of dentition in Late Cretaceous and Cenozoic marine vertebrate
predators were analyzed.The analysis included species of Late Cretaceous and
Cenozoic sharks, Late Cretaceous marine reptiles, and Cenozoic marine
mammals. Dental characters used in the study were both discrete and
continuous. Species included in the analysis were originally collected from
Late Cretaceous and Cenozoic rocks from the south-central, southeastern, and
the mid-Atlantic regions of the United States, as well as Europe and the
A morphometric "tooth space" was constructed using the eigenvectors
generated from Principal Component Analysis of the dental character data.The
results of the analysis show that Mesozoic marine reptiles occupied a small,
discrete region of the tooth morphospace, whereas Cretaceous sharks occupied
a much larger, diffuse region of the morphospace. During the Paleogene a
profusion of shark tooth morphologies occurred and then expanded into new
areas of tooth morphospace.Yet, no overlap with the morphospace previously
occupied by Mesozoic marine reptiles occurred.A large number of novel tooth
morphologies evolved with the evolution of marine mammals during the
Cenozoic. Remarkably, many of the tooth forms converged on the Mesozoic
marine reptile designs, and hence a major overlap of marine mammal tooth
morphospace with the previously occupied Mesozoic marine reptile morphospace
occurred.Additionally, the shift from heterodonty (teeth of different types)
to homodonty (teeth of similar types) occurred in several members of both
the Mesozoic marine reptiles and the Cenozoic marine mammals.
Based on dental morphology, this study indicates that following the
extinction of the Mesozoic marine reptiles during the Late Cretaceous,
Cenozoic sharks failed to occupy the vacated niches, yet Cenozoic marine
mammal dentition converged on the previous Mesozoic marine reptile tooth
designs.Apparently, Cenozoic marine mammals occupied
the vacated Mesozoic marine reptile dietary niches.
Jerry D. Harris
Director of Paleontology
Dixie State College
225 South 700 East
St. George, UT 84770 USA
Phone: (435) 652-7758
Fax: (435) 656-4022
"Actually, it's a bacteria-run planet, but
mammals are better at public relations."
-- Dave Unwin