The Hills Have New Papers

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

OK, no they don't...but they _do_ have fossils in 'em...!

Schweitzer, M.H., Elsey, R.M., Dacke, C.G., Horner, J.R., and Lamm, E.-T. 
2007. Do egg-laying crocodilian (Alligator mississippiensis) archosaurs form 
medullary bone? Bone 40(4):1152-1158. doi: 10.1016/j.bone.2006.10.029.

ABSTRACT: It is beyond question that Mesozoic dinosaurs, like Aves and 
Crocodylia, are archosaurs. However, within the archosaurian clade, the 
origin and distribution of some major features are less clear, particularly 
with respect to reproductive physiology. Medullary bone, a highly 
mineralized, bony reproductive tissue present in the endosteal cavities of 
all extant egg-laying birds thus far examined, has recently been reported in 
Tyrannosaurus rex. Its presence or absence in extant crocodilians, 
therefore, may shed light on the timing of its evolutionary appearance. If 
medullary bone is present in all three taxa, it arose before the three 
lineages diverged. However, if medullary bone arose after this divergence, 
it may be present in both extinct dinosaurs and birds, or in birds only. If 
present in extinct dinosaurs and birds, but not crocodilians, it would 
indicate that it arose in the common ancestor of this clade, thus adding 
support to the closer phylogenetic relationship of dinosaurs and birds 
relative to crocodilians. Thus, the question of whether the crocodilian 
Alligator mississippiensis forms medullary bone during the production of 
eggs has important evolutionary significance. Our examination of long bones 
from several alligators (two alligators with eggs in the oviducts, one that 
had produced eggs in the past but was not currently in reproductive phase, 
an immature female and an adult male) shows no differences on the endosteal 
surfaces of the long bones, and no evidence of medullary bone, supporting 
the hypothesis that medullary bone first evolved in the dinosaur-bird line, 
after the divergence of crocodilians from this lineage.



Lucas, S.G., and Tanner, L.H. 2007. The nonmarine Triassic-Jurassic boundary 
in the Newark Supergroup of eastern North America. Earth Science Reviews 
84(1-2):1-20. doi: 10.1016/j.earscirev.2007.05.002.

ABSTRACT: For the last three decades, the position of the Triassic-Jurassic 
boundary (TJB) in nonmarine strata has largely been based on its 
palynostratigraphic placement just below the oldest basalts of the Central 
Atlantic magmatic province (CAMP) in the Newark Supergroup of eastern North 
America. This boundary, however, is demonstrably older than the TJB as it is 
defined in marine strata. Thus, the palynostratigraphic change used to place 
this TJB in the Newark most resembles a late Norian change in the European 
section and does not correspond to any palynological event at the 
marine-defined TJB. Conchostracan biostratigraphy suggests that the TJB is 
in the Newark extrusive zone above the oldest CAMP basalt, and vertebrate 
biostratigraphy is consistent with this placement of the TJB. Radioisotopic 
ages indicate that the TJB defined in marine strata is no older than 200 MA, 
but the oldest CAMP basalts of the Newark Supergroup consistently yield ages 
averaging about 201 Ma. Magnetostratigraphic correlation of the Newark 
section to the TJB section at St. Audrie's Bay in England also indicates 
that the onset of CAMP volcanism in the Newark Supergroup is older than the 
marine TJB. Correlations based on carbon and osmium isotopes are also 
consistent with this correlation. Thus, all data indicate that the TJB in 
the Newark Supergroup is above the lowest CAMP basalt in the Newark 
extrusive zone. Correct placement of the TJB in the Newark Supergroup allows 
key nonmarine and marine events to be sequenced across the TJB, indicating 
the following succession of events: crurotarsan ("thecodont") extinction, 
the palynofloral turnover in the Newark, the first CAMP eruptions, the 
extinctions of Rhaetian ammonites and conodonts, and the first appearance of 
Jurassic psiloceratid ammonites.



Avanzini, M., Dalla Vecchia, F.M., Mietto, P., Piubelli, D., Preto, N., 
Rigo, M., and Roghi, G. 2007. A vertebrate nesting site in northeastern 
Italy reveals unesxpectedly complex beahvior for late Carnian reptiles. 
Palaios 22(5):465-475. doi: 10.2110/palo.2005.p05-137r.

ABSTRACT: We interpret 13 large subcircular or horseshoe-shaped depressions 
discovered in Late Triassic peritidal carbonate rocks of the Dogna Valley in 
Udine Province, northeastern Italy, to be reptile nests. These trace fossils 
show truncation of strata, elevated ridges of massive sediment, and sediment 
infill within the depression differing in shape and sedimentary structures 
from the host sediment. The palynological assemblage of a shaly interbed 
close to the nest layer indicates a Tuvalian age (late Carnian). 
Archosaurian footprints, produced possibly by aetosaurs, are on a surface 
130 cm above the nest-bearing layer. The trackmakers are considered the most 
probable nest makers.



Suarez, C.A., Suarez, M.B., Terry, D.O., Jr., and Grandstaff, D.E. 2007. 
Rare earth element geochemistry and taphonomy of the Early Cretaceous 
Crystal Geyser dinosaur quarry, east-central Utah. Palaios 22(5):500-512. 
doi: 10.2110/palo.2005.p05-126r.

ABSTRACT: The Crystal Geyser Dinosaur Quarry contains a large monospecific 
accumulation of bones from a basal therizinosaur, Falcarius utahensis. The 
quarry is located approximately 16 km south of Green River, Utah, at the 
base of the early Cretaceous (Barremian) Yellow Cat Member of the Cedar 
Mountain Formation. Fossil bones in the quarry occur in three units that 
have distinct taphonomic, lithologic, and geochemical characteristics. Rare 
earth element compositions of fossils suggest that bones from each unit were 
drawn from different reservoirs or sources having distinctly different 
compositions, and fossils were not reworked between units. Compositions of 
bones differ greatly within Units 1 and 2, even within the same 1-m2 quarry 
grid. These chemical differences and taphonomic characteristics, such as 
current orientation, hydraulic sorting, and occasional extensive abrasion, 
suggest that bones from these two units are allochthonous and were 
fossilized at other localities, possibly over an area of several kilometers, 
and were then eroded, transported, and concentrated in a spring-influenced 
fluvial environment. Bones in Unit 3 have very similar rare earth element 
signatures, suggesting that they were probably fossilized in situ at a 
separate time from bones in Units 1 and 2. At least two mass mortality 
events were responsible for the monospecific assemblage of bones at the 
quarry. Because bones may have been concentrated from a wide area, causes of 
mass mortality must have been regionally extensive, possibly owing to 
seasonal drought, sudden changes in weather, or disease.


Suarez, M.B., Suarez, C.A., Kirkland, J.I., González, L.A., Grandstaff, 
D.E., and Terry, D.O., Jr. 2007. Sedimentology, stratigraphy, and 
depositional environment of the Crystal Geyser dinosaur quarry, east-central 
Utah. Palaios 22(5):513-527. doi: 10.2110/palo.2006.p06-014r. ABSTRACT: The 
Crystal Geyser Dinosaur Quarry, near Green River, Utah, is located at the 
base of the Lower Cretaceous (Barremian) Yellow Cat Member of the Cedar 
Mountain Formation. The quarry preserves a nearly monospecific accumulation 
of a new basal therizinosauroid, We used field descriptions and petrographic 
analysis to determine the depositional environment and development of the 
quarry strata. Results of these analyses suggest that the quarry represents 
multiple episodes of bone accumulation buried by spring and overbank flood 
deposits. Evidence for these previously undescribed spring deposits includes 
calcite macroscopic structures within the quarry strata-such as pisolites 
and travertine fragments-and calcite micromorphologies-including 
radial-fibrous, feather, and scandulitic dendrite morphologies and tufa 
clasts. At least two episodes of bone incorporation are preserved in the 
quarry based on their stratigraphic position and lithologic associations. 
The unique depositional setting in and around the Crystal Geyser Dinosaur 
Quarry appears to have been favorable for the preservation of vertebrate 
fossils and provides insight into early Cretaceous environments in North 
America.



Chin, K. 2007. The paleobiological implications of herbivorous dinosaur 
coprolites from the Upper Cretaceous Two Medicine Formation of Montana: why 
eat wood? Palaios 22(5):554-566. doi: 10.2110/palo.2006.p06-087r.

ABSTRACT: Rare assemblages of woody coprolites from different strata of the 
Two Medicine Formation provide surprising perspectives on the feeding 
behavior of Late Cretaceous ornithischian dinosaurs. Most of the irregularly 
shaped, calcareous specimens are largely composed of fragmented conifer wood 
(13%-85%) and can be identified as coprolites by the presence of distinctive 
backfilled dung beetle burrows. The large size (up to 7 L in volume), 
fibrous contents, and associated bones and eggshell strongly suggest that 
the source animals at one site were Maiasaura hadrosaurs. The wood-bearing 
coprolites occur in strata ranging in age from 74-80 Ma, revealing a 
recurring (possibly seasonal) habit of wood ingestion. The preponderance of 
wood in the specimens and the absence of recognizable small-diameter twig 
fragments suggest that wood ingestion was intentional-that the coprolite 
producers had not merely consumed wood inadvertently when feeding on the 
leaves and bark of terminal branches. Because undegraded wood provides 
inconsequential nutritive value for vertebrates, it is unlikely that 
ornithischians would have expended the energy to masticate intact wood for 
little benefit. Furthermore, patterns of tissue damage in the fecal wood 
fragments suggest fungal degradation. Thus, the most parsimonious 
explanation for the high fecal wood content is that the coprolite producers 
consumed decomposing wood to capitalize on resources released by fungal 
attack, along with the tissues of the decomposers and associated 
invertebrate detritivores. These multiple coprolite deposits provide direct 
fossil evidence of recurring dinosaur diets and suggest that some 
ornithischians at least occasionally tapped detrital resources. Although 
such feeding behavior is rare in large extant herbivores, utilization of 
rotting wood would have augmented the resource options of Cretaceous 
ecosystems that lacked fodder provided by grasses and other derived 
angiosperms.

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

STORIES IN SIX WORDS OR LESS:

"Machine. Unexpectedly, I'd invented
a time"
              -- Alan Moore

"Easy. Just touch the match to"
              -- Ursula K. Le Guin

"Batman Sues Batsignal: Demands
Trademark Royalties."
              -- Cory Doctorow