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A Production of

Bathygenys reevesiFossil, Oreodont
Dr. Ted Macrini - St. Mary's University
Bathygenys reevesi
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skull
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Texas Memorial Museum (TMM 40209-198)

Image processing: Dr. Ted Macrini
Image processing: Dr. Jessie Maisano
Publication Date: 21 Dec 2009

ITIS TNS Google MSN

The imagery on this page is the basis for a paper entitled Description of a digital cranial endocast of Bathygenys reevesi (Merycoidodontidae; Oreodontoidea) and implications for apomorphy-based diagnosis of isolated, natural endocasts, by T. E. Macrini (2009, Journal of Vertebrate Paleontology 29:1199-1211). The abstract is as follows:

       Relatively few studies of cranial endocasts document intraspecific variation. Here, discrete        morphological and morphometric variation from a sample of more than 150 natural cranial endocasts        from a single Eocene locality, Reeves Bonebed (hereafter ‘RBB’) from West Texas are documented.        The first description of a digital endocast of an oreodont, Bathygenys reevesi (see Additional Imagery),        is given to provide comparative data for other oreodont endocasts. The RBB endocasts were originally        assigned to B. reevesi, but virtually none has diagnostic craniodental material still attached, and        isolated endocasts of other cetartiodactyl species are known from this locality. Consequently, an        attempt was made to identify apomorphies on the RBB sample to diagnose specimens to the lowest        possible taxonomic level. The RBB endocasts were diagnosed as oreodonts based on the presence of        large, rounded casts of the tuberculum olfactorium, but no specimen can be diagnosed to a        particular species. The range for most linear measurements for the RBB sample overlapped with        measures from multiple species of oreodonts from RBB. A coefficient of variation analysis of linear        measurements suggests that the RBB sample represents more than one species. Therefore, endocasts        from RBB that lack associated craniodental material cannot be definitively assigned to a species, and        the original assumption that all are B. reevesi is not supported. This illustrates the necessity of        applying apomorphy-based identifications for isolated specimens, including endocasts. In addition, this        study reveals some gaps in data from cetartiodactyl brains, which need to be filled for future studies        on brain evolution in this clade.

About the Species

This specimen, the holotype, was collected from the early Chadronian Chambers Tuff Formation, Reeves Bone Bed, Presidio Co., Texas. It was made available to the University of Texas High-Resolution X-ray CT Facility for scanning by Dr. Ted Macrini of St. Mary's University. Funding for scanning was provided by a University of Texas Geology Foundation grant for analytical fees to Eric Ekdale.

About this Specimen

The specimen was scanned by Matthew Colbert on 13 June 2006 along the coronal axis for 642 slices. Each 1024x1024 pixel slice is 0.1413 mm thick, with an interslice spacing of 0.1413 mm and a field of reconstruction of 64 mm.

About the
Scan

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Literature
& Links
endocast pitch movie

Click on the thumbnail to the left for a pitch animation (2.6 mb) of the isolated Bathygenys cranial endocast.

endocast rollmovie

Click on the thumbnail to the left for a roll animation (3.0 mb) of the isolated Bathygenys cranial endocast.

Additional
Imagery

To cite this page: Dr. Ted Macrini, 2009, "Bathygenys reevesi" (On-line), Digital Morphology. Accessed November 1, 2014 at http://digimorph.org/specimens/Bathygenys_reevesi/.

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