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Sherlock New Papers
Xing, L.-D., Harris, J.D., Sun, D.-H., and Zhao, H.-Q. 2009. The earliest known
deinonychosaur tracks from the Jurassic-Cretaceous boundary in Hebei Province,
China. Acta Palaeontologica Sinica 48(4):662-671.
ABSTRACT: Herein we describe a single trackway that pertain to Menglongipus
sinensis ichnogen. et ichnosp. nov. from the Nijiagou track site in the
Chicheng county, Hebei Province. China. The tracks occur in the Tuchengzi
Formation, which spans the Jurassic-Cretaceous boundary. The discovery of M.
sinensis indicates that deinonychosaurians occupied this area prior to
deposition of the Yixian Formation. from which the oldest deinonychosaur body
fossils in the region have been found. The body length (about 65cm) of the M.
sinensis track maker is very similar to that estimated for basal paravians.
Additional details are provided about the type Velociraptorichnus sichuanensis
and the association between dromaeopodid and other theropod tracks is discussed.
Doody, J.S., Freedberg, S., and Keogh, J.S. 2009. Communal egg-laying in
reptiles and amphibians: evolutionary patterns and hypotheses. Quarterly Review
of Biology 84(3):229-252. doi: 10.1086/605078.
ABSTRACT: Communal egg-laying is widespread among animals, occurring in
insects, mollusks, fish, amphibians, reptiles, and birds, just to name a few.
While some benefits of communal egg-laying may be pervasive (e.g., it saves
time and energy and may ensure the survival of mothers and their offspring),
the remarkable diversity in the life histories of the animals that exhibit this
behavior presents a great challenge to discovering any general explanation.
Reptiles and amphibians offer ideal systems for investigating communal
egg-laying because they generally lack parental careâa simplification that
brings nest site choice behavior into sharp focus. We exhaustively reviewed the
published literature for data on communal egg-laying in reptiles and
amphibians. Our analysis demonstrates that the behavior is much more common
than previously recognized (occurring in 481 spp.), especially among lizards (N
= 255 spp.), where the behavior has evolved multiple times. Our conceptual
review strongly suggests that different forces may be driving the evolution and
maintenance of communal egg-laying in different taxa. Using a game theory
approach, we demonstrate how a stable equilibrium may occur between solitary
and communal layers, thus allowing both strategies to co-exist in some
populations, and we discuss factors that may influence these proportions. We
conclude by outlining future research directions for determining the proximate
and ultimate causes of communal egg-laying.
Ishigaki, S., and Matsumoto, M. 2009. 'Off-tracking'-like phenomenon observed
in the turning sauropod trackway from the Upper Jurassic of Morocco. Memoir of
the Fukui Prefectural Dinosaur Museum 8:1-10.
ABSTRACT: A turning trackway of a large sauropod dinosaur was discovered from
the Upper Jurassic IouaridÃne Formation in the Central High Atlas Mountains,
Morocco. Its turning angle is 56Â to the left. It is remarkable that the manus
prints are imprinted outside of the pes trackway at the turning point. The gap
between the trackway midlines of manus and pes imprints reaches its maximum
width at the very point of turning. Other sharp turning trackways of large
sauropods previously discovered from Utah and Switzerland present similar gaps
between the two midlines. However, such gap is not recognized in the turning
small sauropod trackway from Croatia, or in the fossil turning proboscidean
trackway from Japan. A turning trackway of a modern Asiatic elephant presents a
similar gap but in opposite mode. The appearance of the gap might be analogous
to the âoff-trackingâ phenomenon observed in turning four wheel vehicles.
Gleno-acetabular distance, steering ability of the hindlimbs, position of body
mass and the existence of long neck and long tail may affect the appearance of
the phenomenon. The analysis of this phenomenon in the turning trackways of
quadrupedal animals would be useful for investigating the kinematics of extinct
Curtis, N., Jones, M.E.H., Evans, S.E., O'Higgins, P., and Fagan, M.J. 2009.
Visualising muscle anatomy using three-dimensional computer models -- an
example using the head and neck muscles of Sphenodon. Palaeontologia
Electronica 12(3):7T (1-18).
ABSTRACT: We demonstrate how the computer-based technique of multi-body
dynamics analysis (MDA) can be used to create schematic, but informative
three-dimensional (3D) representations of complex muscle anatomy. As an example
we provide an overview of the head and neck muscles present in Sphenodon
(Diapsida: Lepidosauria: Rhynchocephalia). First a computer model based on
micro-computed tomography datasets provides a detailed and anatomically correct
three-dimensional (3D) framework to work from. Secondly, muscles are
represented by groups of cylinders that can be colour coded as desired. This
allows muscle positions, attachment areas, and 3D orientation to be visualised
clearly. This method has advantages over imaging techniques such as
two-dimensional drawings and permits the form and function of the muscles to be
understood in a way that is not always possible with more classical
Bates, K.T., Falkingham, P.L., Breithaupt, B.H., Hodgetts, D., Sellers, W.I.,
and Manning, P.L. 2009. How big was 'Big Al'? Quantifying the effect of soft
tissue and osteological unknowns on mass predictions for Allosaurus
(Dinosauria: Theropoda). Palaeontologia Electronica 12(3):14A (1-33).
ABSTRACT: MOR693, nicknamed 'Big Al,' is the most complete skeleton of the
non-avian theropod Allosaurus and therefore provides the best opportunity to
investigate the mass properties of this important Jurassic theropod through
accurate physical or digital volumetric models. In this study, laser scanning
and computer modelling software have been used to construct volumetric models
of MOR693. A long-range laser scanner has been used to digitize the mounted
cast of MOR693, allowing the reconstruction of body volumes and respiratory
structures around and within the three-dimensional (3D) skeletal model. The
digital medium offered the facility to modify model properties
non-destructively in a detailed sensitivity analysis to quantify the effects of
the many unknown parameters involved in such reconstructions. In addition to
varying the volumes of body segments and respiratory structures, we also extend
the sensitivity analysis to include uncertainties regarding osteological
articulations in non-avian dinosaurs, including effects of inter-vertebral
spacing and the orientation or 'flare' of the rib cage in MOR693. Results
suggest body mass and inertial values are extremely uncertain and show a wide
range in plausible values, whilst the CM (centre of mass) position is well
constrained immediately in front and below the hip joint in MOR693, consistent
with similar reconstructions of non-avian theropods.
Sellers, W.I., Manning, P.L., Lyson, T., Stevens, K., and Margetts, L. 2009.
Virtual palaeontology: gait reconstruction of extinct vertebrates using high
performance computing. Palaeontologia Electronica 12(3):11A (1-26).
ABSTRACT: Gait reconstruction of extinct animals requires the integration of
palaeontological information obtained from fossils with biological knowledge of
the anatomy, physiology and biomechanics of extant animals. Computer simulation
provides a methodology for combining multimodal information to produce concrete
predictions that can be evaluated and used to assess the likelihood of
competing locomotor hypotheses. However, with the advent of much faster
supercomputers, such simulations can also explore a wider range of
possibilities, allowing the generation of gait hypotheses de novo. In this
paper we document the use of an 8000 core computer to produce mechanically and
physiologically plausible gaits and trackway patterns for a sub-adult dinosaur
(Edmontosaurus annectens), evaluating a large range of locomotor possibilities
in terms of running speed. The anatomical reconstruction presented is capable
of running and hopping bipedal gaits; trot, pace and single foot symmetrical
quadrupedal gaits; and asymmetrical galloping gaits. Surprisingly hopping is
the fastest gait (17 ms-1), followed by quadrupedal galloping (16 ms-1) and
bipedal running (14 ms-1). Such a hopping gait is considered unlikely for this
animal, which would imply that either our anatomical and physiological
reconstruction is incorrect or there are important constraints such as skeletal
loading and safety factor that are currently not included in our simulation.
The most likely errors are in joint ranges of motion, combined with the lengths
of muscle fibres and tendons since these values are difficult to reconstruct.
Thus the process of gait simulation is able to narrow down our predictions of
unknown features of the extinct animal using a functional bracket. Trackway
geometries derived from the gait models are currently very basic due to the
simplicity of the ground/foot contact model used, but demonstrate the future
potential of this technology for interpreting and predicting trackway geometry.
Sereno, P.C., and Larsson, H.C.E. 2009. Corrigenda: Sereno PC, Larsson HCE
(2009) Cretaceous Crocodyliforms from the Sahara. ZooKeys 28: 1â143. ZooKeys
29:73-74. doi: 10.3897/zookeys.29.368.
Jerry D. Harris
Director of Paleontology
Dixie State College
225 South 700 East
St. George, UT 84770 USA
Phone: (435) 652-7758
Fax: (435) 656-4022
"The optimist thinks this is the best
of all possible worlds. The pessimist
fears it is true."
-- J. Robert Oppenheimer
"In nuclear war all men are cremated
-- Dexter Gordon