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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: 10.1666/pleo05-164.1.

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 evolutionary context.

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


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

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

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Trademark Royalties."
-- Cory Doctorow