Several New Papers

["Jerry D. Harris" <jharris@dixie.edu>]

Yeah, subject lines like that are boring and redundant and repetitive and 
redundant...

    First, the "official" versions of a couple of previously mentioned 
papers are out:

Ericson, P.G., Anderson, C.L., Britton, T., Elzanowski, A., Johansson, U.S., 
Källersjö, M., Ohlson, J.I., Parsons, T.J., Zuccon, D., and Mayr, G. 2006. 
Diversification of Neoaves: integration of molecular sequence data and 
fossils. Biology Letters 2(4):543-547. doi: 10.1098/rsbl.2006.0523.

ABSTRACT: Patterns of diversification and timing of evolution within 
Neoaves, which includes almost 95% of all bird species, are virtually 
unknown. On the other hand, molecular data consistently indicate a 
Cretaceous origin of many neoavian lineages and the fossil record seems to 
support an Early Tertiary diversification. Here, we present the first 
well-resolved molecular phylogeny for Neoaves, together with divergence time 
estimates calibrated with a large number of stratigraphically and 
phylogenetically well-documented fossils. Our study defines several 
well-supported clades within Neoaves. The calibration results suggest that 
Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, 
diversified around or soon after the K/T boundary. Our results thus do not 
contradict palaeontological data and show that there is no solid molecular 
evidence for an extensive pre-Tertiary radiation of Neoaves.


Nesbitt, S.J., Turner, A.H., Erickson, G.M., and Norell, M.A. 2006. Prey 
choice and cannibalistic behaviour in the theropod Coelophysis. Biology 
Letters 2(4):611-614. doi: 10.1098/rsbl.2006.0524.

ABSTRACT: Direct evidence of prey choice in carnivorous dinosaurs is rare in 
the fossil record. The most celebrated example pertains to purported stomach 
contents in the carnivorous dinosaur Coelophysis bauri, which besides 
revealing prey choice, also points to cannibalistic behaviour as being 
commonplace (Colbert 1989, 1995). Here, we test this hypothesis by 
conducting the first comprehensive anatomical and histological examination 
of the famed Coelophysis 'cannibals'. The results unequivocally show that 
the gut contents derive from early crocodylomorphs rather than juveniles of 
Coelophysis. These findings suggest that this taxon is not cannibalistic and 
bring into question the commonality of this behaviour among non-avian 
dinosaurs.


Also new:

Schweitzer, M.H., Wittmeyer, J.L., and Horner, J.R. 2006. Soft tissue and 
cellular preservation in vertebrate skeletal elements from the Cretaceous to 
the present. Proceedings of the Royal Society of London B. doi: 
10.1098/rspb.2006.3705.

ABSTRACT: Soft tissues and cell-like microstructures derived from skeletal 
elements of a well-preserved Tyrannosaurus rex (MOR 1125) were represented 
by four components in fragments of demineralized cortical and/or medullary 
bone: flexible and fibrous bone matrix; transparent, hollow and pliable 
blood vessels; intravascular material, including in some cases, structures 
morphologically reminiscent of vertebrate red blood cells; and osteocytes 
with intracellular contents and flexible filipodia. The present study 
attempts to trace the occurrence of these four components in bone from 
specimens spanning multiple geological time periods and varied depositional 
environments. At least three of the four components persist in some skeletal 
elements of specimens dating to the Campanian. Fibrous bone matrix is more 
altered over time in morphology and less likely to persist than vessels 
and/or osteocytes. Vessels vary greatly in preservation, even within the 
same specimen, with some regions retaining pliability and other regions 
almost crystalline. Osteocytes also vary, with some retaining long filipodia 
and transparency, while others present with short and stubby filipodia and 
deeply pigmented nuclei, or are pigmented throughout with no nucleus 
visible. Alternative hypotheses are considered to explain the origin/source 
of observed materials. Finally, a two-part mechanism, involving first 
cross-linking of molecular components and subsequent mineralization, is 
proposed to explain the surprising presence of still-soft elements in fossil 
bone. These results suggest that present models of fossilization processes 
may be incomplete and that soft tissue elements may be more commonly 
preserved, even in older specimens, than previously thought. Additionally, 
in many cases, osteocytes with defined nuclei are preserved, and may 
represent an important source for informative molecular data.


Three from _Cretaceous Research_:

Candeiro, C.R.A., Martinelli, A.G., Avilla, L.S., and Rich, T.H. 2006. 
Tetrapods from the Upper Cretaceous (Turonian-Maastrichtian) Bauru Group of 
Brazil: a reappraisal. Cretaceous Research 27(6):923-946. doi: 
10.1016/j.cretres.2006.05.002.

ABSTRACT: An updated, annotated list of all tetrapods from the Adamantina, 
Uberaba and Marília formations (Bauru Group), which constitute some of the 
best studied Upper Cretaceous units in Brazil, is presented. Tetrapod 
diversity in the Bauru Group is remarkable, including an admixture of 
typically austral Gondwanan taxa (e.g., abelisaurids, notosuchians) and 
boreal Gondwanan forms (e.g., carcharodontosaurids). Of note is the absence 
of Laurasian taxa in the upper portion of the Bauru Group. With the 
exception of some turtles, an anuran, mesoeucrocodylians and one titanosaur, 
most taxa from the Bauru Group are based on fragmentary and isolated bones, 
and as such many specimens can be identified only to a higher taxonomic 
level. Fishes, turtles, anurans, mesoeucrocodylians, dinosaurs, birds and 
mammals from the Adamantina and Marília formations resemble the latest Late 
Cretaceous vertebrate faunas from southern South America, except for the 
absence of ornithischian dinosaurs.


Mezga, A., Meyer, C.A., Tesovic, B.C., and Gusic, I. 2006. The first record 
of dinosaurs in the Dalmatian part (Croatia) of the Adriatic-Dinaric 
carbonate platform (ADCP). Cretaceous Research 27(6):735-742. doi: 
10.1016/j.cretres.2006.01.001.

ABSTRACT: The first discovery of dinosaur footprints on the Dalmatian part 
of the Adriatic-Dinaric carbonate platform (ADCP) is reported. They 
constitute the geologically youngest record of footprints on the ADCP. The 
trackbearing layer was formed in the intertidal environment and represents 
the final stage of a shallowing-upward cycle. Just below it, a heavy 
dinoturbated limestone layer can be observed. Microfacies analysis, 
incorporating evidence from benthic foraminifera and algae, indicates a Late 
Turonian-Early Coniacian age. The overall morphology and size of the 
footprints points to sauropod dinosaurs; they represent the largest forms 
recorded so far on the ADCP. This hints at a prolonged sauropod presence on 
the platform and to its Late Cretaceous connection to the continent rather 
than isolation.


Dyke, G.J., Malakhov, D.V., and Chiappe, L.M. 2006. A re-analysis of the 
marine bird Asiahesperornis from northern Kazakhstan. Cretaceous Research 
27(6):947-953. doi: 10.1016/j.cretres.2006.05.001.

ABSTRACT: Fossil bird material is exceptionally rare in the Mesozoic of 
western Asia. With the notable exception of the Upper Cretaceous 
foot-propelled diving bird Asiahesperornis bazhanovi from northern 
Kazakhstan, the only bird fossils described from this region have been bone 
fragments from the Upper Cretaceous of Uzbekistan. In this paper, all 
material referred to date to the hesperornithiform Asiahesperornis is 
reviewed and re-described. New postcranial elements of this taxon from the 
holotype Kushmurun locality (Maastrichtian Zhuravlovskaya Svita) are 
presented, and the taxonomic history and likely affinities of this 
ocean-going bird are discussed.


Lastly:

Kong, H., Chen, C.-R., Dang, Y.-M., Yang, J.-G., Huang, Q.-H., and Zhao, 
C.-B. 2006. On three Cretaceous biotas of Songliao Basin. Acta 
Palaeontologica Sinica 45(3):416-424.

ABSTRACT: The Cretaceous biotas divided in ascending order into the Jehol 
Biota in the faulted period, the Songhuajiang Biota in the depressed period 
and the Mingshui Biota in the atrophied period, are well developed and 
widely distributed. This paper summarizes systematically the main characters 
of each biota and reveals the general biota features, the general characters 
vertically and the significance on the research of biostratigraphy, 
ecological environment and paleoclimate.


Therrien, F. 2006. Depositional environments and fluvial system changes in 
the dinosaur-bearing Sânpetru Formation (Late Cretaceous, Romania): 
post-orogenic sedimentation in an active extensional basin. Sedimentary 
Geology 192(3-4):183-205. doi: 10.1016/j.sedgeo.2006.04.002.

ABSTRACT: The Sânpetru Formation (Hateg Basin, Romania) was deposited in an 
active extensional basin in response to the post-orogenic collapse of the 
Southern Carpathians. Despite being one of the best exposed latest 
Cretaceous continental successions of Eastern Europe and having great 
potential to improve knowledge about the Mesozoic evolution of the 
Carpathian orogen and the latest Cretaceous terrestrial paleoenvironments of 
Europe, this formation has been the subject of limited sedimentologic 
research. Fourteen stratigraphic sections were measured in the Sânpetru 
Formation throughout an 860-m-thick interval exposed along the Sibisel 
Valley in order to conduct the most detailed stratigraphic and 
sedimentologic study of this formation to date.
    The Sânpetru Formation is a repetitive succession of fining-upward 
units composed of stratified and structureless sandstones, conglomerates, 
and mudstones. Facies analysis reveals that the Sânpetru Formation was 
deposited by braided streams that flowed through a symmetrical, extensional 
basin. The low variability of paleocurrent direction, the sheet-like 
architecture of the deposits, and the paucity of channel-shaped scours 
indicate poorly channelized flow across a shallow, broad braidplain.
Small-scale fluctuations in sandstone/mudstone ratio and maximum grain size 
of channel deposits in the lower Sânpetru Formation reflect autocyclic 
shifts in paleochannel position. In the upper Sânpetru Formation, 
sandstone/mudstone ratios and maximum grain size of channel deposits 
increase, paleocurrent direction changes significantly, and hydromorphic 
paleosols become the sole type of paleosols present. These changes reflect 
an episode of rapid uplift of the source area and the basinward creation of 
accommodation space below the local water table, which resulted in the 
creation of extensive wetlands. The wetlands of the upper Sânpetru Formation 
were not an environment favorable for the formation of dinosaur bonebeds, 
which are found in the lower part of the formation. The apparent absence of 
fossils in the upper part of the formation led previous researchers to 
incorrectly interpret the Cretaceous-Tertiary boundary at the transition 
between the lower and upper Sânpetru Formation.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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/

"Trying to estimate the divergence times
of fungal, algal or prokaryotic groups on
the basis of a partial reptilian fossil and
protein sequences from mice and humans
is like trying to decipher Demotic Egyptian with
the help of an odometer and the Oxford
English Dictionary."
              -- D. Graur & W. Martin (_Trends
                  in Genetics_ 20[2], 2004)