New Papers: Saurolophus from California; Archosaur Soft-Tissue Preservation

[bh480@scn.org]

From: Ben Creisler
bh480@scn.org

In case these have not been mentioned yet:

Phil R. Bell and David C. Evans, 2010.
Revision of the status of Saurolophus (Hadrosauridae) 
from California, USA.
Canadian Journal of Earth Sciences 47(11): 1417?1426 
(2010)|

http://pubs.nrc-cnrc.gc.ca/rp-ps/inDetail.jsp?
jcode=cjes&lang=eng&vol=47&is=11


Abstract: The occurrence of Saurolophus from the Moreno 
Formation (late Maastrichtian) of California is 
investigated and an incomplete, poorly preserved, skull 
(LACM/CIT 2852) is described. The skull lacks the 
braincase (including the frontals) and much of the 
nasals, and the preserved portions are crushed or 
plastically deformed, which makes anatomical 
interpretations difficult. A preserved midline fragment 
of the conjoined nasals suggests that it lacked a 
gryposaur-like ?Roman nose?, but the nature of the crest, 
if present, is impossible to determine with certainty. A 
phylogenetic analysis places this specimen as either the 
sister taxon of Saurolophus or as the sister taxon to a 
clade comprising Edmontosaurus and Anatotitan. There is 
no compelling morphological evidence to support the 
previous assignment of LACM/CIT 2852 to Saurolophus 
rather than to Edmontosaurus, and its poor preservation 
prevents positive assignment to any taxon below 
Hadrosaurinae indet. Given its geographic setting and 
morphological uncertainties, it is also possible that 
this specimen represents a separate taxon, but more 
material is needed to clarify the identity of the Moreno 
hadrosaurine. LACM/CIT 2852 does, however, provide 
evidence that Maastrichtian hadrosaurines ranged west of 
the Sierra Nevada magmatic arc, in an area where dinosaur 
diversity is poorly known.


----



Joseph E Peterson, Melissa E Lenczewski, Reed P Scherer, 
2010.
Influence of Microbial Biofilms on the Preservation of 
Primary Soft Tissue in Fossil and Extant Archosaurs.
PLos ONE online publication
http://www.plosone.org/article/info%3Adoi%2F10.1371%
2Fjournal.pone.0013334

Mineralized and permineralized bone is the most common 
form of fossilization in the vertebrate record. 
Preservation of gross soft tissues is extremely rare, but 
recent studies have suggested that primary soft tissues 
and biomolecules are more commonly preserved within 
preserved bones than had been presumed. Some of these 
claims have been challenged, with presentation of 
evidence suggesting that some of the structures are 
microbial artifacts, not primary soft tissues. The 
identification of biomolecules in fossil vertebrate 
extracts from a specimen of Brachylophosaurus canadensis 
has shown the interpretation of preserved organic remains 
as microbial biofilm to be highly unlikely. These 
discussions also propose a variety of potential 
mechanisms that would permit the preservation of soft-
tissues in vertebrate fossils over geologic time.

This study experimentally examines the role of microbial 
biofilms in soft-tissue preservation in vertebrate 
fossils by quantitatively establishing the growth and 
morphology of biofilms on extant archosaur bone. These 
results are microscopically and morphologically compared 
with soft-tissue extracts from vertebrate fossils from 
the Hell Creek Formation of southeastern Montana (Latest 
Maastrichtian) in order to investigate the potential role 
of microbial biofilms on the preservation of fossil bone 
and bound organic matter in a variety of taphonomic 
settings. Based on these analyses, we highlight a 
mechanism whereby this bound organic matter may be 
preserved.

Results of the study indicate that the crystallization of 
microbial biofilms on decomposing organic matter within 
vertebrate bone in early taphonomic stages may contribute 
to the preservation of primary soft tissues deeper in the 
bone structure.

====
Donald M. Henderson and Darren H. Tanke, 2010.
Estimating past and future dinosaur skeletal abundances 
in Dinosaur Provincial Park, Alberta, Canada.
Canadian Journal of Earth Sciences 47(10): 1291?1304 
(2010) 
http://pubs.nrc-cnrc.gc.ca/rp-ps/inDetail.jsp?
jcode=cjes&vol=47&is=10&lang=eng

Abstract: Some 353 isolated skulls and partial to 
complete skeletons with known locations have been 
collected in ~100 years from the 80 km2 of badlands in 
Dinosaur Provincial Park (DPP), Alberta, Canada. We 
wanted to estimate how many skeletons were lost to 
erosion before collection began and how many await 
discovery. Within the boundaries of DPP, a volume of rock 
145 m thick between the surface of the down-cutting Red 
Deer River and the capping prairie was subdivided into 5 
m thick slabs using digital elevation data with an 
average horizontal spatial resolution of 19 m and a 
vertical resolution of 1 m. The exposed surface area of 
each slab was calculated. Dinosaur fossil localities were 
determined with high-precision GPS surveys. The number of 
dinosaurs collected from the surface of a 5 m slab was 
divided by the product of the exposed area and an 
estimated erosional thickness of 80 cm to give a volume 
density of dinosaur fossils. Multiplying the volumes of 
rock lost from each layer by the dinosaur densities for 
each layer, the numbers of skeletons lost was determined. 
Estimates of the numbers of raisins in two loaves of 
raisin bread were made using a limited number of slices 
as a test of the method. Of the original volume of DPP, 
6.58 km3 (60%) has eroded away, taking with it a mean 
number of 6310 hadrosaurs, 1640 ceratopsians, 1030 
ankylosaurs, and 1600 theropods. The 5.02 km3 (40%) of 
rock remaining in the park can be expected to produce 
more dinosaur fossils of similar quality, with mean 
values of 6700 hadrosaurs, 1700 ceratopsians, 1010 
ankylosaurs, and 1720 theropods. These estimates are 
minima as the estimation process excluded bone beds, the 
plethora of isolated bones littering the land surface of 
DPP, and the 100+ skulls and skeletons from the region 
that lack locality information.



Juan Carlos Cisneros, Uiara Gomes Cabral, Frikkie de 
Beer, Ross Damian, Daniel Costa Fortier. 2010 
Spondarthritis in the Triassic.
PLos One

http://www.plosone.org/article/info%3Adoi%2F10.1371%
2Fjournal.pone.0013425

The evidence of several forms of arthritis has been well 
documented in the fossil record. However, for pre-
Cenozoic vertebrates, especially regarding reptiles, this 
record is rather scarce. In this work we present a case 
report of spondarthritis found in a vertebral series that 
belonged to a carnivorous archosaurian reptile from the 
Lower Triassic (∼245 million years old) of the South 
African Karoo.

Neutron tomography confirmed macroscopic data, revealing 
the ossification of the entire intervertebral disc space 
(both annulus fibrosus and nucleus pulposus), which 
supports the diagnosis of spondarthritis.

The presence of spondarthritis in the new specimen 
represents by far the earliest evidence of any form of 
arthritis in the fossil record. The present find is 
nearly 100 million years older than the previous oldest 
report of this pathology, based on a Late Jurassic 
dinosaur. Spondarthritis may have indirectly contributed 
to the death of the animal under study.