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Morphometry of the teeth of western North American tyrannosaurids and its applicability to quantitative classification

100%

Samman T., Powell G. L., Currie P. J., Hills L. V.

Acta Palaeontologica Polonica

2005

tom 50

nr 4

757-776

Gross tooth morphology and serration morphology were examined to determine a quantifiable method for classifying tyrannosaurid tooth crowns from western North America. From the examination of teeth in jaws, tyrannosaurid teeth could be qualitatively assigned to one of five types based on the cross−sectional shape of the base of the tooth and characteristics of the mesial carina. A principal component analysis (PCA) revealed that much of the variance in tooth shape was a result of isometry, but some gross morphological variables exhibited strong positive allometry. Non−size associated factors were also important in determining tooth shape, particularly when data on denticle dimensions were considered in the analysis. While PCA identified important factors in variation, PCA ordination plots did not cluster the teeth into distinct, separate groupings based on taxon or bone of origin. The group classification functions determined by discriminant analysis, though not universally successful for classifying unidentified isolated teeth of all tyrannosaurids, do identify bone of origin of adult Albertosaurus, Daspletosaurus, and Gorgosaurus teeth at a statistically acceptable level.

The cranial osteology of Spermophilus richardsonii [Sabine, 1822] [Richardson's ground squirrel] [Mammalia: Rodentia: Sciuridae]

100%

Russell A. P., Pereschitz R. M., Powell G. L.

Annales Zoologici

2001

tom 51

nr 1

Much is known of the ecology and behaviour of Spermophilus richardsonii (Sabine, 1822) (Richardson's Ground Squirrel), but little has been discussed of its anatomy. Here we document details of its cranial anatomy, based upon 95 specimens from a single locality, focusing primarily on previously undescribed features. This documentation provides the essential information for studying intra- and interpopulational variation in cranial characteristics in both quantitative and qualitative contexts. Skulls of S. richardsonii examined were generally uniform in structure, and no obvious sexual differences were observed.

Ograniczanie wyników

1 Acta Palaeontologica Polonica

1 Annales Zoologici

2 Powell G. L.

1 Currie P. J.

1 Hills L. V.

1 Pereschitz R. M.

1 Russell A. P.

1 Samman T.

1 2005

1 2001

Wyniki wyszukiwania

Morphometry of the teeth of western North American tyrannosaurids and its applicability to quantitative classification

The cranial osteology of Spermophilus richardsonii [Sabine, 1822] [Richardson's ground squirrel] [Mammalia: Rodentia: Sciuridae]