Urocyon galushai, TEDFORD R. H. & WANG X. & TAYLOR B. E., 2009

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 : 72-73

Urocyon galushai , new species Figure 7, 29H–K; appendix 3

Urocyon atwaterensis Getz, 1960: 363 (nomen vanium).

Urocyon cf. progressus Akersten, 1970: 19 .

Urocyon sp. : Dalquest, 1978: 287.

Etymology: Named in honor of the late Ted Galusha, Frick Curator Emeritus, American Museum of Natural History, who collected the holotype and many of the specimens used in this review.

Type: F:AM 63104, right and left partial mandibular rami with c (broken)–m2 (m1 broken and m3 alveolus), maxillary fragment with P3, isolated P4 and M1 (broken), partial scapula, distal end humerus, proximal part of ulna, distal end of tibia, right calcaneum and left partial calcaneum, proximal ends of metatarsals II, IV, and V, and distal end of a metapodial from the 111 Ranch (Dry Mountain) locality (late Blancan latest Gauss Chron and 4 m below correlated Mount Blanco Ash Bed, 2.32 ± 0.15 Ma, Galusha et al., 1984), San Simon Valley, Graham County, Arizona.

Referred Material: Red Light Local Fauna, Love Formation (late Blancan, Akersten, 1970), southeastern Hudspeth County, Tex- as: TMM 40855-15, partial left ramus with alveoli for p4–m3*.

Beck Ranch Local Fauna, 10 miles east of Snyder (early Blancan fide Dalquest, 1978), Scurry County, Texas: MSU 9475, right P4*; MSU 9476, left P4*; MSU 8569*, left m2*; MSU 9474, left p4*.

Cita Canyon beds (late Blancan), Randall County, Texas: JWTU (uncataloged), M1 (fig. 29H) and broken upper canine.

Vallecito Creek, Upper Diablo-Tapiado Wash, LACM locality 6856, Palm Springs Formation (Blancan), San Diego County, California: LACM 17210, crushed anterior part of skull with I3–P4 represented by alveoli and roots.

LACM locality 1298, Geomys Bed, zone 55.0, Palm Springs Formation (early Irvingtonian), San Diego County, California: LACM 3839, left partial ramus with p1 (root)–m1 all broken, m2 and m3 alveolus. LACM locality 6814, Palm Springs Formation (early Irvingtonian), San Diego County, California: LACM 53678, left partial ramus with m1 (broken), m2, and m3 (alveolus).

Distribution: Early to late Blancan of Texas, late Blancan of Arizona and California, and early Irvingtonian of California.

Diagnosis: Autapomorphies that distinguish U. galushai are: elongate and deep horizontal ramus, p1–p2 large relative to other teeth, and ascending ramus with wide separation of condyloid crest and masseteric line.

Differs from Urocyon citrinus in derived features: large premolars; smaller m2 with shorter trigonid, shorter paracristid, and shorter talonid lacking both entoconulid and distinct hypoconulid. Differs from U. minicephalus and U. cineroargenteus in larger, taller crowned premolars; m2 more elongate, narrower, longer trigonid, better developed paracristid, weaker anterobuccal cingulum, weaker protostylid; elongate horizontal ramus; ascending ramus with greater separation between condyloid crest and masseteric line; and more rounded subangular lobe.

Description and Comparison: The type mandibular ramus of U. galushai is elongate with a comparatively deep horizontal ramus. It is larger than that of U. minicephalus and is also larger than the average for U. cinereoargenteus . The ascending ramus is broken and missing above the level of the coronoid process, but enough is present to show that the lateral surface is marked by a greater separation of the condyloid crest and masseteric line. The angular process is also large in these specimens, but the process is attenuate and hooked distally (fig. 29J) and the insertions of the pterygoid musculature have the primitive form seen in other vulpines. Both the type of U. galushai from Arizona and the similar-sized referred mandible from the Blancan of Texas have a rounded subangular lobe with a rugose medial surface rather than the abruptly projecting subangular process characteristic of later Urocyon .

The lower premolars are relatively larger, more elongate, and taller crowned than in U. minicephalus and U. cinereoargenteus . The m 2 in U. galushai , as in U. citrinus , is primitive and similar to that of U. cinereoargenteus scotti and unlike that of U. c. floridanus and U. minicephalus . Compared to the two latter taxa, the m2 of U. galushai and U. c. scotti is more elongate and less complex. The protoconid and metaconid are relatively smaller and situated more posteriorly with the paraconid either a small cusp or a distinct cristid. Moreover, the m2 is less robust, has a narrower talonid, and the anterolabial cingulum and protostylid are both weaker than in U. c. floridanus and U. minicephalus .

In addition to the Blancan mandibular fragment described by Akersten (1970: 19), an isolated M1 and broken canine from the Cita Canyon beds in the Panhandle-Plains Historical Museum collection are also referred to U. galushai . The M1 (JWTU uncataloged, fig. 29H) differs from that of the type of U. galushai in its weaker labial cingulum at the base of the metacone and its relatively larger hypocone. The hypocone is anteroposteriorly longer and higher crowned, differing from the M1 referred to U. progressus in the same way. Although the lingual cingulum narrows at the anterior base of the protocone, it is much stronger than that of the type M1 of U. galushai or U. progressus , and the cingulum is continuous across the labial surface of the protocone. Despite the above differences, the Blancan M1 from Texas is referred to U. galushai because an examination of a recent population of U. c. floridanus from Thomas County, Georgia, showed that the M1 is variable in these same feataures. Unfortunately, no comparison can be made with any corresponding elements of U. citrinus . Hence, the most diagnostic of the Blancan specimens from Texas is the mandibular fragment with rounded subangular lobe that is similar to that of U. galushai and unlike the sharply angled subangular lobe of living Urocyon .

Of the four isolated teeth from the Beck Ranch, the m2 is the most diagnostic. It is smaller than that of the type of U. galushai and morphologically like that of U. c. scotti. The m2 is elongate and slender and less robust and less complex than that of U. c. floridanus. Compared to the latter, the protoconid and metaconid are smaller and situated less anteriorly with a well-developed paracristid. The anterolabial cingulum is small and the protostylid weak as in U. galushai and similar to that in U. c. scotti.

Discussion: Getz (1960: 363) based U. atwaterensis on a M2 from the Borchers Local Fauna (late Blancan), Meade County, Kansas, and stated, ‘‘The M2 has a well developed cingulum and is wider than Recent forms. A small cusp is present between the protocone and metacone.’’ It can be demonstrated with a series of recent specimens of U. cinereoargenteus that the strength of the cingulum on M2 is somewhat variable, as in the development of the metaconule (‘‘the small cusp between the protocone and metacone’’). U. atwaterensis is therefore considered a nomen vanum.

U. galushai appears more derived than the later occurring U. citrinus athough they share a rounded subangular lobe. When compared with U. minicephalus and U. cinereoargenteus floridanus , it is primitive in most characters that can be observed. On the other hand, U. galushai is unique in its elongate horizontal ramus with large anterior premolars and the presence of a widely separated condyloid crest and masseteric line. These characters serve to isolate it from other species of Urocyon .