New Papers of a Shopaholic

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

...or should that be "Literature Junkie"?  Anyway...



Nesbitt, S.J., Turner, A.H., Spaulding, M., Conrad, J.L., and Norell, M.A. 
2009. The theropod furcula. Journal of Morphology. doi: 10.1002/jmor.10724.

ABSTRACT: The furcula is a structure formed by the midline fusion of the 
clavicles. This is the element which is unique to theropods and is important 
for understanding the link between birds and other theropods. New specimens 
from basal theropods suggest that the furcula appeared very early in theropod 
history. We review furcula development, function, and morphology, as well as 
the anatomical terminology applied to it. Furcular morphology is highly 
variable in crown-group avians but is rather conserved among nonavian 
theropods. Here we review, or describe for the first time, the furculae in many 
nonavian theropods. Furculae occur in nearly all major clades of theropods, as 
shown by new theropod specimens from the Early Cretaceous of China and a close 
inspection of previously collected specimens. Informative phylogenetic 
characters pertaining to the furcula occur throughout Theropoda, though care 
should betake to consider taphonomic effects when describing furcular 
morphology.



Ãsi, A., and Weishampel, D.B. 2009. Jaw mechanism and dental function in the 
Late Cretaceous basal eusuchian Iharkutosuchus. Journal of Morphology. doi: 
10.1002/jmor.10726.

ABSTRACT: Iharkutosuchus makadii is a basal eusuchian crocodylian with 
multicusped teeth discovered from the Upper Cretaceous of Hungary. Skull and 
dentition morphology indicates an active food processing for this crocodylian. 
First among crocodylians, a combination of different analyses, including 
cranial adductor muscle reconstruction, tooth wear pattern, and enamel 
microstructure studies, is applied here to support this hypothesis. Data 
provide unambiguous evidence for significant dental occlusion that was a result 
of a unique, transverse mandibular movement. Reconstruction of the jaw 
adductors demonstrates strong muscles responsible for slow but active jaw 
closure as the motor of transverse jaw movement; nevertheless muscles producing 
rapid jaw closure were reduced. Macrowear orientations show a dominantly 
transverse movement of the mandibles completed by a slight anteroposterior 
component. Along with quadrate morphology, macrowear further indicates that 
this motion was
 accomplished by alternate rotation of the mandibles about the quadrate 
condyles. Dental morphology and wear patterns suggest two types of power 
stroke: a slicing-crushing stroke associated dominantly with anterior 
tooth-food-tooth contact (with a low degree of transverse mandibular movement) 
during in the early stage of mastication, and a grinding stroke with 
significant posterior tooth-tooth contact and a dynamic transverse movement 
occurring later. The patterns of microwear show a diverse diet for 
Iharkutosuchus including both soft and hard items. This is also supported by 
the microstructure of the thick, wrinkled enamel built up mostly by poorly 
developed columnar units. Based on wear patterns, ontogenetic variation in 
feeding habits of Iharkutosuchus is also recognized.



Anfinson, O.A., Lockley, M.G., Kim, S.H., Kim, K.S., and Kim, J.Y. 2009. First 
report of the small bird track Koreanaornis from the Cretaceous of North 
America: implications for avian ichnotaxonomy and paleoecology. Cretaceous 
Research. doi: 10.1016/j.cretres.2009.02.001.

ABSTRACT: Although body fossils of shorebirds and shorebird-like species are 
extremely rare from the Cretaceous, rapid increase in the discovery of bird 
footprint sites provides valuable alternate evidence to help fill gaps in the 
story of the early evolution of shorebird-like species. Newly discovered bird 
tracks from the Albian â Cenomanian Dakota Formation in northeastern Utah 
represent the first report of the ichnogenus Koreanaornis from North America 
and only the second report of bird tracks from this formation. These tracks are 
not attributable to Aquatilavipes as previously claimed. Three well-preserved 
trackways are described and provisionally referred to Koreanaornis cf. 
hamanensis (Kim). However, a review of the ichnotaxonomy of shorebird ichnites 
reveals that this ichnotaxon also closely resembles the Miocene ichnospecies 
Avipeda sirin (Vyalov). This latter comparison points to the need for a 
thorough evaluation of the similarity between Mesozoic and Cenozoic avian
 ichnotaxa, which may be over-split in some cases and under-differentiated in 
others.
     The new material helps distinguish ichnogenus Koreanaornis from the larger 
bird track Aquatilavipes, which is more abundant and widespread in North 
America. In some cases Aquatilavipes has been incorrectly used as a catch-all 
ichnogenus both in North America and Asia. The Dakota Formation stratigraphy at 
the tracksite indicates that the track makers lived in a marginal marine 
paleoenvironment. However, despite the widespread distribution of such facies, 
often replete with dinosaur tracks, the bird track record of the Dakota 
Formation, and the Cretaceous of the western USA remains relatively sparse in 
comparison with other areas such as east Asia.




Larson, D.W. 2008. Diversity and variation of theropod dinosaur teeth from the 
uppermost Santonian Milk River Formation (Upper Cretaceous), Alberta: a 
quantitative method supporting identification of the oldest dinosaur tooth 
assemblage in Canada. Canadian Journal of Earth Sciences 45(12):1455-1468. doi: 
10.1139/E08-070.

ABSTRACT: The Santonian Deadhorse Coulee Member of the Milk River Formation 
preserves the oldest dinosaur body fossils found in Alberta. However, 
vertebrate remains consist almost exclusively of isolated elements and 
microvertebrate assemblages. Here, 1572 relatively complete shed non-avian 
theropod teeth from 20 localities in the Deadhorse Coulee Member are measured 
and analyzed to assess species diversity. Teeth are referred to or similar to 
Tyrannosaurinae indet., cf. Richardoestesia gilmorei, cf. Richardoestesia 
isosceles, Dromaeosauridae indet., Dromaeosaurinae indet., Velociraptorinae 
indet., and cf. Paronychodon lacustris. For the taxa identified, the large 
sample size allows for the assessment of their range of variation and accurate 
identification, without the benefit of comparable material of this age. 
Multivariate statistics, including a principal component analysis and a 
canonical variate analysis, provide reasonable separation of all taxa, although 
better results are
 achieved by separate analyses based on qualitative observations of denticle 
shape. The best results of the canonical variate analysis identified 96.0% of 
specimens correctly. This corroborates the qualitative identification of 
specimens and illustrates a valid way of evaluating diversity in areas and 
formations from which no described jaw material is known.




Dickenson, W.R., and Gehrels, G.E. 2008. U-Pb ages of detrital zircons in 
Jurassic eolian and associated sandstones of the Colorado Plateau: evidence for 
transcontinental dispersal and intraregional recycling of sediment. Geological 
Society of America Bulletin 121(3/4):408-433. doi: 10.1130/B26406.1.

ABSTRACT: U-Pb ages for 1655 individual detrital zircon grains in 18 samples of 
eolian and associated marine and fluvial sandstones of the Glen Canyon and San 
Rafael Groups from the Colorado Plateau and contiguous areas shed light on 
patterns of Jurassic sediment dispersal within Laurentia. Most detrital zircon 
grains in Jurassic eolianites were derived ultimately from basement provinces 
older thanï 285 Ma of eastern and central Laurentia, rather than from rock 
assemblages of the nearby Cordilleran margin. The most prominent peaks of 
constituent age populations at 420 Ma, 615 Ma, 1055 Ma, and 1160 Ma reflect 
derivation from Paleozoic, Neoproterozoic, and Grenvillian sources within the 
Appalachian orogen or its sedimentary cover. Sediment was transported to a 
position upwind to the north of the Colorado Plateau by a transcontinental 
paleoriver system with headwaters in the central to southern Appalachian 
region, but subordinate non-Appalachian detritus was contributed by both
 northern and southern tributaries during sediment transit across the 
continent. Subordinate detrital zircons younger than 285 Ma in selected Middle 
to Upper Jurassic eolianites were derived from the Permian-Triassic East Mexico 
and the Mesozoic Cordilleran magmatic arcs. Lower Jurassic fluvial sandstones 
typically contain a mixture of detrital zircons redistributed from eolian sand 
and derived from the East Mexico arc, which lay up-current to the southeast. 
Zircons in marine Curtis sandstone were largely reworked from underlying 
Entrada eolianite, with minor contributions from the Jurassic backarc igneous 
assemblage of the Great Basin. Once mature quartzose detritus was dispersed 
widely across southwest Laurentia by a transcontinental paleoriver system and 
paleowinds, which deposited extensive Jurassic ergs, durable zircon grains were 
recycled by multiple intraregional depositional systems. Lower Jurassic fluvial 
sand is locally composed, however, of detritus derived from the nearby
 Cordilleran magmatic arc assemblage and its Preca!
mbrian ba



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

"Life is the art of drawing
sufficient conclusions from
insufficient premises."
               -- Samuel Butler