Cuon alpinus Pallas, 1811

TEDFORD R. H., WANG X. & TAYLOR B. E., 2009, Phylogenetic Systematics Of The North American Fossil Caninae (Carnivora: Canidae), Bulletin of the American Museum of Natural History 2009 (325), pp. 1-218 : 157-161

Cuon alpinus Pallas, 1811 Figure 59A–C; appendix 3

Cuon alpinus: Kurtén and Anderson, 1980: 172 . Cuon sp. : Youngman, 1993: 141.

Material: From San Josecito Cave, Nuevo Leon, northeastern Mexico; LACM ( CIT) locality 192, carbon 14 dating (Arroyo- Cabrales et al., 1995) indicates that the cave fill excavated by CIT ranges from 27 to 11 Ka: LACM 110984, left M1; LACM 28081, fragment of a right ramus with c–p4 alveoli, m1, m2 alveolus; LACM 28082 (site L13) fragment of a right ramus, c root, p2– p3, p4 root; LACM 28083, fragment of a right ramus, p1 root, p2 tip broken, p3–p4, m1, anterior part m2 alveolus; LACM 28084, fragment of right ramus, p1–p2 partial alveoli, p3–p4, m1–m2 partial alveoli; LACM 28085, fragment of left ramus, m1, and alveolus of m2; and LACM 28086 (site B2.60), fragment of left ramus, c–p1 alveoli, p2–p3 roots, p4 alveolus, m1, m2 alveolus.

Description and Comparison: The upper dentition is represented only by a M1; it has the typically short talon of the genus. The tooth lacks conules, the hypocone is very reduced, and a lingual cingulum is absent on the protocone. The labial cingulum is present and complete and there is a low parastyle connected to the paracone by the preparacrista.

The horizontal rami are robust, deep, especially anteriorly. A shallow medioventral extension of the symphysis is present, and the ventral border has an inflection behind the symphysis. The largest mental foramen lies below the anterior root of p2, and there is a smaller foramen beneath p3 and sometimes also a small foramen below p4 as occasionally seen in other species of Cuon . The anterior part of the masseteric fossa is deeply indented so that the anterior rim overhangs the fossa. The premolars lack diastemata and p1–p2 and p2–p3 may be imbricated. All premolars have anterior cinguli, but only that on p4 is produced into a prominent anterior cusp that is canted medially in the manner of a carnassial paraconid. Premolars 3 and 4 have posterior cusps and p4 has a second cusp lying just in front of the posterior cingulum. The crown of p4 tips backward and its principal cusp is taller than the m1 paraconid. This tilt results in the base of the crown of p4 lying well above the base of p3, but the p3 principal cusp does not lie below that of p2. The anterior face of the m1 paraconid slants backward, and the metaconid is low and very reduced and is only slightly higher than the hypoconid. The talonid is unicuspid but the hypoconid lies a little labial to the midline. It is compressed laterally into a crest that reaches forward to the base of the protoconid. The crista obliqua is very low and is directed to the base of the metaconid. There is only a low crest lingually, which rises to a union with the tip of the hypoconid. No specimen shows the m2, but the alveoli have an interradicular crest that indicates the presence of a weakly two-rooted tooth. There is no m3.

This sample compares most favorably with C. alpinus europaeus from the latest Pleistocene of Europe. It agrees closely in size with samples allocated to that taxon ( Adam, 1959: table 2) and particularly in the morphology of the p4 with its large anterior cusp. Nevertheless, there are some peculiarities of the m1 talonid that would need closer comparison than can be undertaken, and so the San Josecito specimen is referred simply to Cuon alpinus without subspecific designation.

Discussion: It is a zoogeographic surprise to see a single record of Cuon in North America at a mid-latitude late Rancholabrean site. The presence of several individuals is in accord with the pack-hunting behavior of the living dholes, but with hundreds of known sites of this age scattered across the United States and Mexico, the occurrence of this taxon in only a single place is a sobering reminder of the paucity of our real knowledge of the fossil record of even the youngest sites. Today Cuon ranges into northeastern Asia and is thus poised to traverse Beringia during favorable low sea-level episodes. So far only Xenocyon has been recorded in Alaska and northern Canada. Perhaps competitive exclusion forced Cuon into southern North America to avoid wolves and Xenocyon at higher latitudes.

PHYLETIC ANALYSIS