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Many New Papers



Some still new from '05; others brand-spankin' new!

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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 Salmantiscensia 41:39-43.

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.

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Averianov, A. O., T. Martin, S. E. Evans, and A. A. Bakirov. 2006. First Jurassic Choristodera from Asia. Naturwissenschaften 93(1):46-50. doi: 10.1007/s00114-005-0061-2.

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.


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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.

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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 event deposit.


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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 Pacific Rim.
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
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/

"Actually, it's a bacteria-run planet, but
mammals are better at public relations."
                                     -- Dave Unwin