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Some More New Papers



Hi All -

Some more announcements! This first one is from a new book that I guess must be out now, though it's not listed yet on the Association's web site. If anyone knows how to get a hold of it (and how much it costs!), please let us know!

Bonnan, M., and Senter, P. 2007. Were the basal sauropodomorph dinosaurs Plateosaurus and Massospondylus habitual quadrupeds?; pp. 139-155 in Barrett, P.M. and Batten, D.J. (eds.), Evolution and Palaeobiology of Early Sauropodomorph Dinosaurs. Special Papers in Palaeontology 77. Palaeontological Association, London.

ABSTRACT: The basal sauropodomorph dinosaurs Plateosaurus and Massospondylus are often portrayed as habitual quadrupeds that were facultatively bipedal. Surprisingly, the functional morphology of their forelimbs has rarely been considered when reconstructing their locomotor habits. If Plateosaurus and Massospondylus were efficient, habitual quadrupeds we predict that the manus would have been pronated such that it produced a caudally directed force in parallel with the pes. We articulated and manipulated the forelimbs of Plateosaurus, Massospondylus and several extant outgroup taxa (Varanus, Alligator, Anser and Struthio) using a standardized protocol. Moreover, we compared our results with previously published estimates of forelimb movement in saurischian outgroup taxa from Theropoda and Sauropoda and with the basal sauropodomorph/sauropod Melanorosaurus. Our results indicate that the range of motion in the forelimbs of Plateosaurus and Massospondylus did not allow efficient, habitual quadrupedal locomotion. The range of humeral flexion and abduction is limited and the articular surfaces of the radius and ulna orient the palmar surfaces of the manus medially in semi-supination. Active or passive pronation of the manus was not possible and the manus could not function in a dynamically similar way to the pes for efficient quadrupedal locomotion. Our results also rule out specialized forms of quadrupedal locomotion, such as the knuckle-walking gait of some mammals. We suggest that most known "prosauropod" trackways were probably not made by animals such as Plateosaurus or Massospondylus, but the ichnotaxon Otozoum may have been created by animals similar to these taxa. Furthermore, we show that trunk and limb ratios do not yield consistent results and should not be used solely to determine posture. Although these two taxa probably assumed a quadrupedal posture as hatchlings, we show that the morphological orientations of the forelimb elements remained consistent across ontogeny, precluding efficient, quadrupedal locomotion at any age. As with theropods, forelimb use in basal sauropodomorphs is difficult to reconstruct and interpret. We speculate that the forelimb could have aided in acquiring vegetation or defence in Plateosaurus and Massospondylus only if these animals reared or assumed a tripodal posture.

   These for the track-lovers out there:

Hurum, J., Milàn, J., Hammer, Ø., Midtkandal, I., Amundsen, H., and Saether, B. 2006. Tracking polar dinosaurs - new finds from the Lower Cretaceous of Svalbard. Norwegian Journal of Geology 86:397-402.

ABSTRACT: A new discovery of ornithopod dinosaur tracks from Svalbard is described. The Lower Cretaceous (Barremian) section at Isfjorden consists of sandstones and interbeds consistent with an alluvial flood plane. The newly discovered tracks are situated on two different horizons stratigraphically below the original horizon found in 1960. Footprint evidence from Festningen and Kvalvågen suggests that during the Early Cretaceous there was a diverse dinosaur fauna on Svalbard and that both theropods and ornithopods were present at the time.

-- this one is freely available at http://www.geologi.no/data/f/0/09/35/0_22301_0/J._H._Hurum_et_al_lavoppl.pdf.

Mezga, A., Tesovicm, B.C., and Bajraktarevic, Z. 2007. First record of dinosaurs in the Late Jurassic of the Adriatic-Dinaridic Carbonate Platform (Croatia). Palaios 22(2):188-199. doi: 10.2110/palo.2006.p06-043r.

ABSTRACT: All previously known dinosaur remains on the Adriatic-Dinaridic carbonate platform (ADCP) were described from Cretaceous deposits. A new trackbearing locality is late Tithonian in age and represents the oldest evidence of dinosaurs on the ADCP. The site is in an active quarry near the village of Kirmenjak in western Istria. Almost a thousand sauropod footprints including 23 single trackways have been found on the outcrop. Oval impressions represent pes prints, and horseshoe-shaped impressions represent manus prints; pes prints are 23 to 52 cm long. Calculated heights at the hip range from 153 to 306 cm. The main direction of dinosaur movement was toward the northeast, and some of the individuals were moving together. The trackways show a characteristic narrow gauge, and pace and stride lengths indicate a slow walk. The footprints are similar to Parabrontopodus ichnogenus, and the ichnocoenosis could be assigned to the Brontopodus ichnofacies. The presence of the sauropods on the Adriatic-Dinaridic carbonate platform during the Late Jurassic could be explained by connection with the African continent via its southern margins during emersion.

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

"Trying to estimate the divergence times
of fungal, algal or prokaryotic groups on
the basis of a partial reptilian fossil and
protein sequences from mice and humans
is like trying to decipher Demotic Egyptian with
the help of an odometer and the Oxford
English Dictionary."
-- D. Graur & W. Martin (_Trends
in Genetics_ 20[2], 2004)