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Re: Fossils in Argentinosaurus footprints

Martin Lockley also reported crushed unionoid snails in sauropod footprints at the Morrison Purgatorie River site in Colorado.


On 7/13/2012 6:22 AM, Thomas R. Holtz, Jr. wrote:
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
On Behalf Of Martin Baeker

Hi folks,

my google skills have failed me: I have seen a TV documentary
which showed an assembly of small fossils inside an
Argentinosaurus footprint. However, I'm unable to find any
reference for that.

Any hints to a paper (or if possible a pdf) would be very
welcome here...
The sauropod ID (and thus the continent) is totally wrong, but this seems to be 
a misreporting of:

PALAIOS 25(2):112-125. 2010

full access



Three newly discovered bonebeds from the Shishugou Formation of Xinjiang, China, are 
unusual in preserving vertically stacked and articulated to associated skeletons of at 
least 18 small, non-avian theropod dinosaurs in pits that are 1–2 m deep. The 
pits host a soft sediment-deformed mixture of alluvial and volcanic mudstone and 
sandstone. There is no evidence that the pits were discrete depressions in the 
topography that filled through time. Rather, they appear to have been highly localized 
areas of liquefaction caused by large-dinosaur (possibly sauropod) trampling of 
saturated sediments. Evidence indicates that the small theropods, and some other small 
vertebrates, became mired and died in these mud-filled pits. High quality skeletal 
preservation suggests that most individuals were buried within days to months after 
their deaths. Carcasses were buried successively, coming to rest above previously 
buried individuals. In some cases, skeletal body parts became separated or
  were removed, probably during scavenging. Given the large sizes of the pits relative to the small 
body sizes of the vertebrates contained within them, we conclude that small vertebrates (<3 m 
long and <1 m tall) were particularly susceptible to miring at these sites. Although the small, 
presumably herbivorous ceratosaur, Limusaurus inextricabilis, dominates the combined small theropod 
assemblage from these bonebeds (minimum number of individuals [MNI]  =  15), there is 
no evidence that any biological features other than its small size and a large, and possibly, 
gregarious local population were responsible for its becoming mired in large numbers. A bias for 
small theropods in these bonebeds, compared to their relatively low abundance in the overall 
Shishugou Formation fauna, underscores that small theropods are underrepresented in Mesozoic fossil 
assemblages collected from other ancient alluvial and paludal settings.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA

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