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Dr. Strangelove: Or How I Learned to Stop Worrying and Love the New Papers
Nod to Sarah Spears for this title, and to SP & RT for some of the notices!
Too bad there's no mention of Strangelove oceans in any of these...
Tsuihiji, T., and Makovicky, P. 2007. Homology of the neoceratopsian
cervical bar elements. Journal of Paleontology 81(5):1132-1138. doi:
Martinelli, A.G. and Vera, E.I. 2007. Achillesaurus manazzonei, a new
alvarezsaurid theropod (Dinosauria) from the Late Cretaceous Bajo de la
Carpa Formation, Rio Negro Province, Argentina. Zootaxa 1582: 1-17.
ABSTRACT: A new genus and species, Achillesaurus manazzonei gen. et sp.
nov., of the enigmatic clade Alvarezsauridae (Theropoda, Coelurosauria),
recovered from the Santonian Bajo de la Carpa Formation (Río Negro Province,
Argentina), is here described. A. manazzonei is a relatively large
alvarezsaurid different from Alvarezsaurus calvoi (from the same Age and
Formation) in having a lateral fossa in the proximal caudal centra, a less
developed supraacetabular crest, the brevis shelf not reaching the base of
the ischial pedicel, and the lateral malleolus of the tibia at the same
level of the medial one. Achillesaurus differs from Patagonykus puertai,
from the Portezuelo Formation (Neuquén Province, Argentina), by the presence
of an almost undeveloped supracetabular crest of the ilium and the unfused
condition of the astragalus and the calcaneum. The new species is excluded
from the Asian Mononykinae due to the unreduced fibula distally and a
non-arctometatarsalian pes. The autapomorphies of Achillesaurus are the
presence of a biconcave caudal vertebra (possibly the fourth) with the
cranial surface 30% larger in diameter than the caudal one. The inclusion of
Achillesaurus in a phylogenetic framework resulted in an unresolved polytomy
among the new taxon, Alvarezsaurus, and Patagonykus plus Mononykinae, the
latter clade being weakly supported. The result here presented shows a basal
stem radiation of South American alvarezsaurids. New material of the
Patagonian alvarezsaurids is necessary to evaluate relevant traits to test
further the phylogenetic relationships of the basal alvarezsaurids.
Gillman, M.P. 2007. Evolutionary dynamics of vertebrate body mass range.
Evolution 61(3):685-693. doi: 10.1111/0014-3820.2007.00060.x.
ABSTRACT: Change in body mass with time has been considered for many clades,
often with reference to Cope's rule, which predicts a tendency to increase
in body size. A more general rule, namely increase in the range of body mass
with time, is analyzed here for vertebrates. The log range of log vertebrate
body mass is shown to increase linearly and highly significantly with the
log of duration of clade existence. The resulting regression equations are
used to predict the origin age, initial body mass, and subsequent dynamics
of body mass range for primate clades such as the New World monkeys
(Platyrrhini, 32 million years ago, initial mass of 1.7 kg) and the
Anthropoidea (57 million years ago, initial mass of 0.12 kg), tested against
the primate fossil record. Using these methods, other major primate clades
such as Lemuriformes and Adapoidea are also estimated to have originated in
the Tertiary (63 and 64 million years ago, respectively), with only the
Plesiadapiformes originating in the Cretaceous (83 million years ago).
Similarities of body mass range between primate and other vertebrate sister
groups are discussed. Linear relationships of log range and log duration are
considered with respect to Brownian processes, with the expected regression
coefficients from the latter explored through simulations. The observed data
produce regression coefficients that overlap with or are higher than those
under Brownian processes. Overall, the analyses suggest the dynamics of
vertebrate body mass range in morphologically disparate clades are highly
predictable over many tens of million years and that the dynamics of
phenotypic characteristics can assist molecular clock and fossil models in
dating evolutionary events.
Smith, N.C., Payne, R.C., Jespers, K.J., and Wilson, A.M. 2007. Muscle
moment arms of pelvic limb muscles of the ostrich (Struthio camelus).
Journal of Anatomy 211(3):313-324. doi: 10.1111/j.1469-7580.2007.00762.x.
ABSTRACT: Muscle moment arms were measured for major muscles of the pelvic
limb of the ostrich (Struthio camelus) in order to assess specific
functional behaviour and to apply this to locomotor performance. Pelvic
limbs of six juvenile ostriches were used for this study. The tendon travel
technique was used to measure moment arms of 21 muscles at the hip, knee,
ankle and metatarsophalangeal joints throughout the ranges of motion
observed during level running. Six of the 21 muscles measured were found to
have moment arms that did not change with joint angle, whilst the remainder
all demonstrated angle-dependent changes for at least one of the joints
crossed. Moment arm lengths tended to be longest for the large proximal
muscles, whilst the largest relative changes were found for the moment arms
of the distal muscles. For muscles where moment arm varied with joint angle:
all hip muscles were found to have increasing moment arms with extension of
the joint, knee flexors were found to have moment arms that increased with
extension, knee extensor moment arms were found to increase with flexion and
ankle extensor moment arms increased with extension. The greatest relative
changes were observed in the flexors of the metatarsophalangeal joint, for
which a three-fold increase in moment arm was observed from flexion to full
extension. Changes in muscle moment arm through the range of motion studied
appear to optimize muscle function during stance phase, increasing the
effective mechanical advantage of these muscles
Tobalske, B.W. 2007. Biomechanics of bird flight. Journal of Experimental
Biology 210(18):3135-3146. doi: 10.1242/jeb.000273.
ABSTRACT: Power output is a unifying theme for bird flight and considerable
progress has been accomplished recently in measuring muscular, metabolic and
aerodynamic power in birds. The primary flight muscles of birds, the
pectoralis and supracoracoideus, are designed for work and power output,
with large stress (force per unit cross-sectional area) and strain (relative
length change) per contraction. U-shaped curves describe how mechanical
power output varies with flight speed, but the specific shapes and
characteristic speeds of these curves differ according to morphology and
flight style. New measures of induced, profile and parasite power should
help to update existing mathematical models of flight. In turn, these
improved models may serve to test behavioral and ecological processes.
Unlike terrestrial locomotion that is generally characterized by discrete
gaits, changes in wing kinematics and aerodynamics across flight speeds are
gradual. Take-off flight performance scales with body size, but fully
revealing the mechanisms responsible for this pattern awaits new study.
Intermittent flight appears to reduce the power cost for flight, as some
species flap-glide at slow speeds and flap-bound at fast speeds. It is vital
to test the metabolic costs of intermittent flight to understand why some
birds use intermittent bounds during slow flight. Maneuvering and stability
are critical for flying birds, and design for maneuvering may impinge upon
other aspects of flight performance. The tail contributes to lift and drag;
it is also integral to maneuvering and stability. Recent studies have
revealed that maneuvers are typically initiated during downstroke and
involve bilateral asymmetry of force production in the pectoralis. Future
study of maneuvering and stability should measure inertial and aerodynamic
forces. It is critical for continued progress into the biomechanics of bird
flight that experimental designs are developed in an ecological and
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
STORIES IN SIX WORDS OR LESS:
"Machine. Unexpectedly, I'd invented
-- Alan Moore
"Easy. Just touch the match to"
-- Ursula K. Le Guin
"Batman Sues Batsignal: Demands
-- Cory Doctorow