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Singin' In The New Papers

...or "New Papers in the Rain," I suppose (another credit to Sarah S. for the title!)

First, a new dromaeosaurid, brought to my attention by Kazuo Takahashi:

Lü, J.-C., Xu, L., Zhang, X.-L., Ji, Q., Jia, S.-H., Hu, W.-Y., Zhang, J.-M., and Wu, Y.-H. 2007. New dromaeosaurid dinosaur from the Late Cretaceous Qiupa Formation of Luanchuan area, western Henan, China. Geological Bulletin of China 26(7):777-786.

ABSTRACT: A new dromaeosaurid dinosaur Luanchuanraptor henanensis gen. et sp. nov. is erected based on the following characters: about 24 posterior serrations per 5 millimeters on the posterior carnia of teeth; the proximal and posterior extensions of the haemal arch are short and trifurcated; the elongated prezygapophyses of the distal-most caudal vertebrae wrapped the preceding vertebra and the caudal vertebrae bear a low, blade-like neural spine between the prezygapophyses; the medial surface of the coracoid is strongly concave; the shaft of the humerus is straight and the deltopectoral crest extends over almost the proximal half of the humerus. Luanchuanraptor henanensis represents the first dromaeosaurid dinosaur found outside the Gobi region and northeastern China in Asia.

Then some anatomy stuff:

Tsuihiji, T. 2007. Homologies of the iliocostalis, iliocostalis, and hypaxial muscles in the anterior presacral region of extant Diapsida. Journal of Morphology 268(11):986-1020. doi: 10.1002/jmor.10565.

ABSTRACT: Homologies of muscles of the m. longissimus and m. iliocostalis groups in the dorsal and cervical regions, as well as those of the subvertebral muscles and mm. intercostales externi that continue from the dorsal into the cervical regions, in extant Diapsida are proposed based on detailed dissections and published accounts of lepidosaurs, crocodylians, and birds. The morphology of tendons and innervation patterns suggest that the avian m. iliocostalis in the dorsal region include the homologs of both m. longissimus and m. iliocostalis in non-avian diapsids. The conserved nature of the morphology of tendons in palaeognath birds also revealed that the avian mm. intertransversarii in the cervical region consist of muscles of the both m. longissimus and m. iliocostalis groups despite having been treated as a single series of muscles, and thus are not homologous with muscles of the same name in Lepidosauria or Crocodylia. The avian mm. inclusi that lie medial to mm. intertransversarii are homologous with mm. intercostales externi in Lepidosauria and mm. intercostales externi and m. scalenus combined in Crocodylia. Innervation patterns suggest that a muscle (m. iliocostalis capitis) connecting the atlas rib and occiput in Crocodylia includes contributions from the subvertebral layer and m. cucullaris complex, and possibly m. iliocostalis as well. The present findings may serve as a basis for revising the currently used avian nomenclature so that it will reflect homologies of muscles with their non-avian counterparts.

And last, a couple new papers on the Morrison and Cedar Mountain Formations:

Greenhalgh, B.W., and Britt, B.B. 2007. Stratigraphy and sedimentology of the Morrison-Cedar Mountain Formation boundary, east-central Utah; pp. 81-100 in Willis, G.C., Hylland, M.D., Clark, D.L., and Chidsey, T.C., Jr. (eds.), Central Utah - Diverse Geology of a Dynamic Landscape. Utah Geological Association Publication 36. Utah Geological Association, Salt Lake City.

ABSTRACT: The Cedar Mountain Formation has been the focus of numerous paleontological and geological studies aimed at understanding Early Cretaceous dinosaurs and tectonics. A major problem in these studies is that the contact between the Upper Jurassic Morrison and Lower Cretaceous Cedar Mountain Formations is notoriously difficult to identify where the Buckhorn Conglomerate is absent. Our stratigraphic and sedimentologic analysis of these formations in Utah and Colorado permits accurate recognition of this previously enigmatic contact. The top of the Morrison Formation is marked by increases in chert-pebble lags and channelized conglomerates overprinted by paleosols that exhibit iron concentrations, manganesecoated grains, intense red-purple-green mottling, and bleaching. These features indicate a period of reduced accommodation in the Tithonian.
Where the basal Cedar Mountain Formation consists of the Buckhorn Conglomerate or a pebbly mudstone (debritic facies) of the Yellow Cat Member, comprising slightly reworked, angular fragments of Morrison Formation regolith, the formational contact occurs at the base of these members. The Buckhorn Conglomerate and the debritic Yellow Cat pebbly mudstone facies (1) interfinger with each other, indicating time equivalancy, (2) typically grade upsection into sandstones, and (3) comprise a depositional system that locally removes part or all of the paleosol that elsewhere caps the Morrison Formation. In the absence of the Buckhorn and debritic Yellow Cat facies, a fine-grained, maroon, calcareous paleosol marks the base of the Cedar Mountain Formation.
A calcrete/silcrete paleosol complex, indicative of a multi-million-year depositional hiatus, commonly overprints the top of the Buckhorn Conglomerate, portions of the Yellow Cat Member, and in some cases, the Morrison Formation paleosol. Above the calcrete, the Cedar Mountain Formation consists of finegrained overbank deposits with caliche nodules or calcrete horizons (Ruby Ranch Member) and isolated to amalgamated sandstone lenses and beds.

Kowallis, B.J., Britt, B.B., Greenhalgh, B.W., and Sprinkel, D.A. 2007. New U-Pb zircon ages from an ash bed in the Brushy Basin Member of the Morrison Formation near Hanksville, Utah; pp. 75-80 in Willis, G.C., Hylland, M.D., Clark, D.L., and Chidsey, T.C., Jr. (eds.), Central Utah - Diverse Geology of a Dynamic Landscape. Utah Geological Association Publication 36. Utah Geological Association, Salt Lake City.

ABSTRACT: A bentonitic ash bed 8.7 m below the top of the Upper Jurassic Morrison Formation near Hanksville, Utah, has been dated by laser ablation multi-collector inductively coupled plasma mass spectrometry and gives a single-crystal U-Pb zircon age of 149.0 +2.5/-2.2 Ma. This age is statistically the same as the 149.3 ± 0.5 Ma age of an ash bed located 0.5 m below the top of the Brushy Basin Member of the Morrison Formation near Notom, Utah, about 25 km to the west. The Hanksville section has a short section of possible Cedar Mountain Formation (between 0.4 and 7.3 m thick) on top of the Morrison section. Two young contaminant zircons with a peak age of 122.5 Ma in the Brushy Basin ash sample indicate that the Cedar Mountain sediments present here are from the lowermost part of the Cedar Mountain Formation.

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


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