Dinosaur environment and taphonomy papers

[bh480@scn.org]

From: Ben Creisler
bh480@scn.org

In case these recent papers have not been mentioned:

Zhong He Zhou and Yuan Wang, 2010.
Vertebrate diversity of the Jehol Biota as compared with 
other lagerstätten. 
SCIENCE CHINA Earth Sciences 53(12), 1894-1907
DOI: 10.1007/s11430-010-4094-9 


In the last twenty years, the extraordinary discoveries 
of vertebrate fossils from the Jehol Biota not only have 
important implications for studying the evolution of 
major Mesozoic vertebrate groups, their 
paleobiostratigraphy and paleoenvironmentology, but also 
provide critical evidence for understanding the 
biodiversity changes of the Early Cretaceous ecosystem. 
Currently, the Jehol Biota in a narrow sense (i.e., 
distribution limited to western Liaoning, northern Hebei, 
and southeastern Inner Mongolia) comprises a vertebrate 
assemblage of at least 121 genera and 142 species. Among 
them are 13 genera and 15 species of mammals, 33 genera 
and 39 species of birds, 30 genera and 35 species of 
dinosaurs, 17 genera and species of pterosaurs, 5 genera 
and species of squamates, 5 genera and 7 species of 
choristoderes, 2 genera and species of turtles, 8 genera 
and species of amphibians, 7 genera and 13 species of 
fishes as well as 1 genus and species of agnathan. All 
these known 121 genera are extinct forms, and only a 
small percentage of them (e.g., agnathans, some fishes 
and amphibians) can be referred to extant families. The 
Jehol vertebrate diversity already exceeds that of the 
contemporaneous lagerstätten such as Santana Fauna from 
Brazil and the Las Hoyas Fauna from Spain, and is nearly 
as great as that of the Jurassic Solnhofen Fauna and the 
Eocene Messel Fauna from Germany. Therefore, The Jehol 
Biota undoubtedly represents a world class lagerstätte in 
terms of both fossil preservation and vertebrate 
diversity. The success of the Jehol vertebrate diversity 
had a complex biological, geological, and 
paleoenvironmental background. Analysis of the habitat 
and diet of various vertebrate groups also indicates that 
the habitat and dietary differentiation had played a key 
role in the success of the taxonomic diversity of 
vertebrates of various ranks. Furthermore, the 
interactions among vertebrates, plants, and invertebrates 
as well as the competitions among various vertebrate 
groups and some key morphological innovations also 
contributed to the success of the Jehol vertebrate 
diversity. 
Keywords  Jehol Biota - Early Cretaceous - vertebrate - 
diversity - lagerstätten 

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http://www.springerlink.com/content/4104714046602277/

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Gareth J. Dyke, 2010.
Palaeoecology: Different Dinosaur Ecologies in Deep Time?
Current Biology 20(22): R983-R985 (23 November 2010)
DOI: 10.1016/j.cub.2010.10.001

Do dinosaurs from the Moroccan Kem Kem formation provide 
evidence for an ecosystem dramatically different from 
anything seen today? More likely the common 
palaeontological problem of time-averaging has had a part 
to play.


http://www.cell.com/current-biology/abstract/S0960-9822
(10)01228-5

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BENJAMIN A. SCHERZER and DAVID J. VARRICCHIO, 2010.
TAPHONOMY OF A JUVENILE LAMBEOSAURINE BONEBED FROM THE 
TWO MEDICINE FORMATION (CAMPANIAN) OF MONTANA, UNITED 
STATES. 
Palaios 25(12): 780?795.
DOI: 10.2110/palo.2009.p09-143r 
 
The Sun River Bonebed is a monodominant assemblage of 
late juvenile lambeosaurine elements from the Upper 
Cretaceous Two Medicine Formation of north-central 
Montana, United States. Detailed excavation revealed an 
unusual paleobiologic and depositional signature. 
Although the bonebed occurs in a succession of beds 
representing anastomosing stream deposits in a seasonal 
paleoenvironment, the assemblage consists of a 
conglomerate of bone and calcareous clasts in a matrix of 
silty mud and free-floating sand grains. Internally, the 
bed exhibits normal grading of bone and calcareous 
clasts, poor sediment sorting, and preferred orientation 
of elongate elements, all characteristics common to 
debris flow deposits. The mud-rich matrix, poor sorting, 
and graded clasts of the bonebed suggest the assemblage 
was entrained and deposited by a cohesive debris flow, 
perhaps initiated through entrainment of fine overbank 
sediment by a seasonal flood. Nearly complete skeletal 
disarticulation and weathering of some bones indicate a 
brief period of postmortem exposure prior to debris flow 
entrainment. Fracture styles suggesting fresh breaks and 
frequent abrasion may reflect pre-flow trampling or 
chaotic flow transport. A significant number of elements 
also exhibit wet rot. The uniformity in taphonomic 
effects among elements suggests a mass mortality event, a 
rarity for debris-flow-hosted bonebeds, though the 
specific cause of death is uncertain. The age class 
dominance is interpreted to reflect original 
paleobiology, rather than abiotic postmortem selection, 
and establishes the Sun River Bonebed as the first 
bonebed of predominantly late juvenile material, with no 
adult material, in the Two Medicine Formation.

http://www.bioone.org/doi/full/10.2110/palo.2009.p09-143r