Gymnorhinus Cyanocephalus

REFERRED MATERIAL Proximal half of left mandible, DMNH 35392.

provenance Location 644, Velvet Room, grid 11, level 4 (B).

DESCRIPTION This specimen compares well in size and characters to the living species. It was also compared to Cyanocitta stelleri, Aphelocoma californica, Nucifraga columbiana, and Perisoreus canadensis. All these genera are distinct, especially in their relative size and the morphology of the post-articular and articular processes of the mandible. DMNH 35392 most closely matches Gymnorhinus cyanocephalus in these features.

DISCUSSION This specimen represents the earliest fossil record of this species. It has also been reported from the late Pleistocene of Mexico and New Mexico and from archaeological sites in Utah and Arizona (Brodkorb, 1978; Steadman et al., 1994a). G. cyanocephalus is found primarily in pinyon-juniper forests in Colorado today, at an elevational range of 1680-2440 m.


REFERRED MATERIAL Left humerus missing proximal end, DMNH 11332; left carpometacarpus, DMNH 30195.

provenance 11332: Location 644, Velvet Room, grid 9, level 6 (C); 30195: Location 1342, Ferret Room.

DESCRIPTION These specimens compare closely in size and characters to the living species. Pica hudsonia occurs in riparian zones and mountain parks throughout Colorado today.


REFERRED MATERIAL Left coracoid missing ends, DMNH 30205; distal right tibiotarsus, DMNH 41100; distal right tar-sometatarsus, DMNH 43342; distal left tarsometatarsus, CM 75132.

PROVENANCE 30205: Location 1349, Mark's Sink (PC-10); 43342: Location 1349, Mark's Sink, level 25; 41100: Location 644, Velvet Room, grid 7, level 16 (E); CM 75132: Badger Room.

DESCRIPTION The specimen is distinctly smaller than Corvus corax and compares well in size and characters to C. brachyrhynchos.


REFERRED MATERIAL Right humerus missing distal end, UCMP 175013; proximal half of left carpometacarpus, CM 73316; humeral half of right coracoid, DMNH 30197; proximal right femur, DMNH 30205; left tibiotarsus missing proximal end, CM 73315; right tarsometatarsus missing portion of proximal end, DMNH 30198; distal right tarsometatarsus, DMNH 10974.

PROVENANCE CM 73315, 73316: Location CM 2203, Crystal Room (no age correlation); 30197 and 30198: Location 942, Badger Room (PC-1); 30205: Location 1349, Mark's Sink (PC-10); 10974: Location 644, Velvet Room, grid 7, level 22 (no age correlation); 175013: Location 1349, Mark's Sink, grid 1, level 1, 2, or 3.

DESCRIPTION These specimens are slightly smaller and more slender than modern specimens of Corvus corax but are distinctly larger than C. cryptoleucus. They probably represent a slightly smaller temporal form of the living species. Magish and Harris (1976) described an extinct raven, C. neomexicanus, from the late Pleistocene of New Mexico. Later, additional material was tentatively referred to this species from the late Pleistocene of Utah (Emslie and Heaton, 1987). This extinct raven is distinguished from C. corax only by its smaller size, and Brodkorb (1978) considered it to be synonymous with C. corax. The tarsometatarus (DMNH 30198) has an approximate length of 64.1 mm and depth of the distal middle trochlea of 5.1 mm; DMNH 10974 is 5.5 mm in the latter measurement. These measurements more closely approximate C. corax in size, as documented by Magish and Harris (1976:table 1), although the trochlea depth of DMNH 30198 is small. Based on these comparisons, the Porcupine Cave material is not considered to represent the extinct species C. neomexicanus.

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