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New Papers Are All Right
Godefroit, P., and Motchurova-Dekova, N. 2010. Latest Cretaceous hadrosauroid
(Dinosauria: Ornithopoda) remains from Bulgaria. Comptes Rendus Palevol. doi:
10.1016/j.crpv.2010.05.003.
ABSTRACT: Disarticulated dinosaur bones have been discovered in a fossiliferous
lens in the Labirinta Cave, southwest of the town of Cherven Bryag, in NW
Bulgaria. This cave is formed within marine limestones belonging to the Kajlâka
Formation of Latest Cretaceous age. Associated fossils and Sr isotopy suggest
that the fossiliferous sediments belong to the uppermost part of the Upper
Maastrichtian. The dinosaur bones discovered in this lens include the distal
portion of a left femur, a right tibia, the proximal part of a right fibula, a
left metatarsal II, the second or third phalanx of a left pedal digit IV, the
proximal end of a second metacarpal, and a caudal centrum. All the bones
undoubtedly belong to ornithopod dinosaurs and more accurately to
representatives of the hadrosauroid clade. All belong to small-sized
individuals, although it cannot be assessed whether they belong to juveniles or
small-sized adults, pending histological analyses. Hadrosauroid remains have
already been discovered in Late Maastrichtian marine sediments from western,
central and eastern Europe, reflecting the abundance of these dinosaurs in
correlative continental deposits. Indeed, hadrosauroids were apparently the
dominating herbivorous dinosaurs in Eurasia by Late Maastrichtian time.
Eme, J., Gwalthney, J., Owerkowicz, T., Blank, J.M., and Hicks, J.W. 2010.
Turning crocodilian hearts into bird hearts: growth rates are similar for
alligators with and without right-to-left cardiac shunt. Journal of
Experimental Biology 213(15):2673-2680. doi: 10.1242/jeb.042051.
ABSTRACT: The functional and possible adaptive significance of non-avian
reptiles' dual aortic arch system and the ability of all non-avian reptiles to
perform central vascular cardiac shunts have been of great interest to
comparative physiologists. The unique cardiac anatomy of crocodilians – a
four-chambered heart with the dual aortic arch system – allows for only
right-to-left (R–L; pulmonary bypass) cardiac shunt and for surgical
elimination of this shunt. Surgical removal of the R–L shunt, by occluding the
left aorta (LAo) upstream and downstream of the foramen of Panizza, results in
a crocodilian with an obligatory, avian/mammalian central circulation. In this
study, R–L cardiac shunt was eliminated in age-matched, female American
alligators (Alligator mississippiensis; 5–7 months of age). We tested the
hypothesis that surgical elimination of R–L cardiac shunt would impair growth
(a readily measured proxy for fitness) compared with sham-operated, age-matched
controls, especially in animals subjected to exhaustive exercise. While regular
exercise caused a decrease in size (snout-to-vent length, head length and body
mass), elimination of the capacity for R–L cardiac shunt did not greatly reduce
animal growth, despite a chronic ventricular enlargement in surgically altered
juvenile alligators. We speculate that, despite being slightly smaller,
alligators with an occluded LAo would have reached sexual maturity in the same
breeding season as control alligators. This study suggests that crocodilian R–L
cardiac shunt does not provide an adaptive advantage for juvenile alligator
growth and supports the logic that cardiac shunts persist in crocodilians
because they have not been selected against.
Kikuchi, R., and Vanneste, M. 2010. A theoretical exercise in the modeling of
ground-level ozone resulting from the K-T asteroid impact: its possible link
with the extinction selectivity of terrestrial vertebrates. Palaeogeography,
Palaeoclimatology, Palaeoecology 288(1-4):14-23. doi:
10.1016/j.palaeo.2010.01.027.
ABSTRACT: The extinction pattern of the Maastrichtian indicates that long-term
and short-term events contributed to the Cretaceous–Tertiary (K–T) mass
extinction at 65 Ma. However, it is not clear how the impact events are linked
with the extinction selectivity; e.g. non-avian dinosaurs became extinct,
whereas birds survived. The post-impact air quality is discussed, and attention
is focused on the then land vertebrates. Although ground-level (tropospheric)
O3 is a powerful irritant on the order of 0.1 ppm toxicity, the presence of
ground-level O3 has hardly been considered since the K–T impact theory was
reported about 30 years ago. Under the post-impact conditions reconstructed by
simulating the carbon cycle (including isotope balance) and impact chemistry, a
trajectory model suggests that the then photochemical reactions formed
ground-level O3 whose concentration was apparently low at not, vert, similar
1.0 ppm, but it is much greater than the current level of not, vert, similar
0.04 ppm: that is, an O3 concentration above the health-threatening level
persisted on the ground after the K–T impact. All land vertebrates must have
suffered from respiratory O3 irritation at the time. However, analysis suggests
that variables of O3 characteristics – hourly variation, short half-life in
water and decomposition due to catalytic effects in soil – were randomly
combined with variables of lifestyle features such as habitat, torpor, etc. to
form new variables (i.e. survival rates): a high survival probability for
amphibians; middle/high probabilities for semi-aquatic reptiles, mammals and
birds; low/middle probabilities for marsupials and terrestrial reptiles; and a
zero probability for non-avian dinosaurs.
Martin, T., Averianov, A.O., and Pfretzschner, H.-U. 2010. Mammals from the
Late Jurassic Qigu Formation in the Southern Junggar Basin, Xinjiang, Northwest
China pp. in Martin, T., Sun, G., and Mosbrugger, V. (eds.), Triassic-Jurassic
Biodiversity, Ecosystems, and Climate in the Junggar Basin, Xinjiang, Northwest
China.
ABSTRACT: Five mammalian taxa based on teeth and jaw fragments are reported
from a bonebed of the Late Jurassic (Oxfordian) Qigu Formation at the
Liuhuanggou site in the southern Junggar Basin. The mammals recovered to date
comprise a new eleutherodontid haramiyid, the docodonts Dsungarodon and
Tegotherium, an undetermined amphilestid triconodont, and a new species of the
stem zatherian Nanolestes and represent the most diverse Late Jurassic mammal
assemblage of Asia. The Liuhuanggou mammal assemblage is dominated by
docodonts. Acuodulodon Hu et al., 2007 from the upper part of the Shishugou
Formation (Oxfordian) of the Wucaiwan area in the central Junggar Basin is a
junior synonym of Dsungarodon Pfretzschner and Martin, 2005.i Tegotherium has
been reported from the Late Jurassic Shar Teeg locality in Mongolia. With the
exception of the common occurrence of Nanolestes, the mammalian assemblage from
the Late Jurassic of the Guimarota coal mine (Portugal) is quite different from
that of the Late Jurassic Qigu Formation. The Guimarota assemblage is dominated
by five genera of dryolestidans and several genera of multituberculates, which
have not been reported from the Qigu assemblage. The known Late Jurassic
mammalian assemblages of Asia are similar to the Middle Jurassic assemblages
known from Asia and elsewhere in the world.
Namba, Y., Yamazaki, Y., Yuguchi, M., Kameoka, S., Usami, S., Honda, K., and
Isokawa, K. 2010. Development of the tarsometatarsal skeleton by the lateral
fusion of three cylindrical periosteal bones in the chick embryo (Gallus
gallus). Anatomical Record. doi: 10.1002/ar.21179.
ABSTRACT: An avian tarsometatarsal (TMT) skeleton spanning from the base of
toes to the intertarsal joint is a compound bone developed by elongation and
lateral fusion of three cylindrical periosteal bones. Ontogenetic development
of the TMT skeleton is likely to recapitulate the changes occurred during
evolution but so far has received less attention. In this study, its
development has been examined morphologically and histologically in the chick,
Gallus gallus. Three metatarsal cartilage rods radiating distally earlier in
development became aligned parallel to each other by embryonic day 8 (ED8).
Calcification initiated at ED8 in the midshaft of cartilage propagated
cylindrically along its surface. Coordinated radial growth by fabricating bony
struts and trabeculae resulted in the formation of three independent bone
cylinders, which further became closely apposed with each other by ED13 when
the periosteum began to fuse in a back-to-back orientation. Bone
microstructure, especially orientation of intertrabecular channels in which
blood vasculature resides, appeared related to the observed rapid longitudinal
growth. Differential radial growth was considered to delineate eventual surface
configurations of a compound TMT bone, but its morphogenesis preceded the
fusion of bone cylinders. Bony trabeculae connecting adjacent cylinders emerged
first at ED17 in the dorsal and ventral quarters of intervening tissue at the
mid-diaphyseal level. Posthatch TMT skeleton had a seemingly uniform
mid-diaphysis, although the septa persisted between original marrow cavities.
These findings provide morphological and histological bases for further
cellular and molecular studies on this developmental process
Liutkus, C.M., Beard, J.S., Fraser, N.C., and Ragland, P.C. 2010. Use of
fine-scale stratigraphy and chemostratigraphy to evaluate conditions of
deposition and preservation of a Triassic Lagerstätte, south-central Virginia.
Journal of Paleolimnology 44(2):645-666. doi: 10.1007/s10933-010-9445-1.
ABSTRACT: The rich, fossiliferous Triassic sediments exposed in the Virginia
Solite Quarry include a 34-mm-thick “insect layer” that is notable for detailed
preservation of soft-bodied invertebrate and vertebrate remains. We describe
this unique Konservat-Lagerstätte and use sedimentologic and geochemical
analyses to interpret the environmental conditions necessary to preserve such
delicate fossils. This work is among the first attempts to apply detailed
geochemical/stratigraphic analysis to the study of Lagerstätten and we report
on a 332-mm-thick section that includes the insect layer and the rocks
immediately below and above it. Our analysis successfully constrains various
aspects of the depositional and diagenetic history of the Lagerstätte and
permits a detailed analysis of changing conditions prior to, during, and after
deposition. Geochemical and sedimentologic analyses of the insect layer and
surrounding lithologies reveal a change from siliciclastic-dominated layers
(Unit 1) to dolomite-siliciclastic laminites above (Unit 2 and the insect
layer), separated by a boundary dolostone layer that is traceable for over 200
m. We interpret this sedimentary shift as the initial stages in the
transgression of a shallow, saline, alkaline rift-basin lake over lake margin
deposits. The absence of bioturbation by plants and benthic organisms, as well
as a lack of predation on the insects, is not explained by significant water
depth, but is instead more reasonably considered a result of the chemistry of
the water at the lake margin, affected by groundwater seeps, which provided F-,
Mg-, and Ca-rich fluids. Although the initial conditions of preservation are
remarkable, it is equally impressive that the fossils survived extensive
diagenesis, e.g. dissolution of quartz and coarsening of dolomite.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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/
The way to a man's heart is through
his stomach.
-- old proverb
"The way to a man's heart is through
the fourth and fifth ribs."
-- Katchoo (and others)