Vulpes kernensis, 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 : 48-56

Vulpes kernensis , new species Figure 23A–D; appendix 3

Type: LACM 55215, right partial maxillary fragment with P3–M2 (fig. 23A–B) from the Kern River Formation, early Hemphillian, CIT locality 49, southeastern San Joaquin Valley, Kern County, California.

Referred Material: LACM 55216, left partial ramus with p4–m1 (fig. 23C–D) from the type locality.

Distribution: Known only from the early Hemphillian of California.

Diagnosis: Differs from V. stenognathus in approximately 20%–25% smaller dentition, P3 and p4 anteroposteriorly shorter, and P4 protocone smaller; differs from V. macrotis and V. velox in P3 and p4 anteroposteriorly shorter and taller crowned relative to length, p4 weaker posterior cusplet, and M1 paracone taller crowned relative to height of metacone. As in living species, the M1 parastyle is very reduced and the preparacrista is not united with parastyle, and the m1 entoconid has a transverse cristid passing to the base of the hyperconid.

Description and Comparison: The dentition of V. kernensis is about 20% smaller than values of V. stenognathus . The type maxilla ( LACM 55215) is within the size range of V. velox . It differs from V. velox in the taller crowned P3 relative to its length, weaker P4 protocone, and relatively taller crowned paracone of M1 relative to the height of the metacone.

The referred jaw ( LACM 55216) compares best with that of V. macrotis , and the m1 is within the size range of that taxon. Like the P3, the p4 is also anteroposteriorly shorter and taller crowned relative to its length than that of V. macrotis . When compared with its length, the height of the m1 crown of V. kernensis is taller than that of V. macrotis . In these characters, V. kernensis closely resembles the Clarendonian Leptocyon tejonensis , which is characterized by closely spaced and anteroposteriorly short premolars with weak posterior cusps. Derived characters that distinguish V. kernensis from L. tejonensis are the taller crowned P3–P4, M1 with smaller parastyle unconnected with the preparacrista and weaker labial cingulum and taller crowned m1 with a more elongate trigonid relative to the length of the talonid, a less oblique paraconid, and an entoconid with a low entoconulid. Additionally, the M2 of V. kernensis has both a postprotocrista and metaconule as in most Vulpes , rather than the reduced state of these features shown in late Leptocyon species. These differences incline us toward the view that V. kernensis is a species of Vulpes rather than Leptocyon . It is coeval with the larger V. stenognathus in the early Hemphillian of western North America, but it is not recorded in the late Hemphillian.

Vulpes stenognathus Savage, 1941 Figures 3, 7, 17, 18I–K, 19–22, 27, 52; appendices 2–4

Leptocyon cf. vafer (Leidy) : Cook and Macdonald, 1962: 562.

Lectotype: OMNH 15167 (formerly OMP 40-4-S24), a right ramus with p2–m3, listed and figured by Savage (1941: fig. 4) as a cotype is here selected as the lectotype. Optima Local Fauna, Ogallala Group (late Hemphillian), near Guymon , Texas County , Oklahoma.

Referred from the Type Locality: Optima Local Fauna, Ogallala Gourp (late Hemphillian), near Guymon, Teas County, Oklahoma: OMNH 15166 (formerly OMP 40-4- S10), right partial ramus with p1–p4, listed as a cotype by Savage (1941: 694); Savage also listed two m1s, four M1s, four M1s, and two M2s as cotypes and figured the following: OMP 40-25-S12, M1 (fig. 2); OMP 40-25- S11, M2 (fig. 3); also figured by Savage, OMP 40-25-S10*, upper canine (fig. 1); F:AM 62942, left P4; F:AM 62940, left partial maxilla with P4–M2; F:AM 62939, right maxilla fragment with P4; F:AM 62938, left partial maxilla with P4–M1 (fig. 18I); F:AM 62956, left p4; F:AM 62950*, associated detached left P4–M2 and right M1–M2; F:AM 62956A, right P4; F:AM 62956B, right P4; F:AM 62944, left maxilla with P2–P4; F:AM 62945, right partial maxilla with P4; F:AM 62941, right partial maxilla with P2– P4; F:AM 62921, right partial ramus with p3–m2; F:AM 62927, left partial ramus with p3–m2 (fig. 18J–K); F:AM 62928, right ramus with p2–m2 (p3 broken); F:AM 62920, right ramus with c (broken)–m2 (broken); F:AM 62926, right ramus with c (broken)–m2; F:AM 62931*, right partial ramus with p2–p4 and m1–m2 (alveoli); F:AM 62957, isolated left m1; F:AM 62961A–F:AM 62961F, seven isolated M1s; F:AM 62961G, H, J–M, six isolated m1s; F:AM 62935, left partial ramus with p4, m2, and alveoli and right partial ramus with p1– m2 (p2–p3 broken); F:AM 30391*, right partial ramus with p1 (p4 and m1 broken); F:AM 30395*, left partial ramus with p3–p4 (p1, p2, and m1 alveoli); F:AM 30396, left ramus, all alveoli; F:AM 30398, right ramus, p2–m3 alveoli.

Thousand Creek Formation (early Hemphillian), Humbolt County, Nevada: LACM 55211, skull fragments and associated dentition including right P4 broken–M1 and M2 broken and right partial ramus with p1 alveolus, p2 broken, p3–m3 alveoli, CIT locality 63; UCMP 84639, left partial maxilla with P1 (alveolus)–P4, UCMP locality V69106 ; and F:AM 63214, right partial maxilla with P3, P4 broken, M1–M2, north end of Railroad Ridge.

Alturas I, UCMP locality V3594, Alturas Formation (early Hemphillian), Modoc County, California; UCMP 24234, left partial ramus with p3–m1 (p4 and m2 broken).

Burmeister locality, UCMP locality V73061 , Rome beds (early Hemphillian), Malheur County, Oregon: UCMP 112195, isolated right P3 and M1.

Rattlesnake 3, UCMP locality 3042, Rattlesnake Formation (early Hemphillian), Grant County, Oregon: UCMP 29969, right m1.

University of Oregon localities 2451 and 2489, Juniper Creek Canyon, Grassy Mountain Formation (early Hemphillian), Malheur County, Oregon: UO 19028, left m1; UO 19029, left P4; and UO 19034, left m2.

Aphelops Draw, Snake Creek Formation (early Hemphillian), Sioux County, Nebraska: AMNH 81021 (HC 519), right m1, described by Cook and Macdonald (1962: 562).

UNSM locality Ft 40, Ash Hollow Formation (early Hemphillian), Frontier County, Nebraska: UNSM 26136, left m1.

Ward’s North Valley Pit, Sebits Ranch, Ogallala Group (early Hemphillian), Lips- comb County, Texas: F:AM 101237, immature partial mandible with i3 (unerupted), dc– dp4 and m1–m2 unerupted, and cranial fragments.

From Miami Quarry (5 Coffee Ranch of University of California, late Hemphillian), 8 miles east of Miami, Hemphill County, Texas: F:AM 23376D, right isolated P4; F:AM 23376E*, right broken P4; F:AM 23376A*, left broken m1; F:AM 23375, left ramus with p2 (broken)–p4 and alveoli; F:AM 23376, left partial ramus with p2–p3.

From Goodnight area (late Hemphillian), Armstrong County, Texas: F:AM 49323, left m1 and associated calcaneum, Hill Pit 19– 20 miles southwest of Claude; F:AM 49321, left broken P4, Hubbard Place Quarry.

From Black Wolf Creek (late Hemphillian), vicinity of Wray, Yuma County, Colorado: F:AM 28348, right and left rami with i1–m3 (fig. 20H–I); F:AM 28349, right and left partial rami with i1–i3 broken and c– m3 (p1 and p3 alveoli); and F:AM 28349A, left partial maxilla with p4 (broken)–M2 and associated isolated teeth including C, P4, M1 broken, and M2.

Chamita Formation (late Hemphillian), Rio Arriba County, New Mexico: F:AM 27412B, right ramus with c (broken)–m2 (p2, p4, and m1 broken), opposite Alcalde; F:AM 62825, right and left partial rami with c (broken) and p2–m1 (all broken), opposite Lyden; F:AM 62830, right partial ramus with m1–m3 (m3 broken), Lyden; F:AM 62832, right partial ramus with c–p4 (broken or alveoli) and m1, K mile North of Lyden Quarry; F:AM 62831, right and left rami with c–p2 broken and p3–m3, K mile west of Lyden Quarry; and F:AM 62837, left partial ramus with p2–m2, m3 broken, Alcalde.

Spring Valley near Panaca, Golgotha Water Mill Pothole site (late Hemphillian), Lincoln County, Nebraska: F:AM 49284, partial skull with I1–I2 alveoli, I3–M2 (P1 and P3 alveoli), right and left rami with c– m3, vertebrae, and fragments (fig. 19); F:AM 49285, right and left partial maxillae with P2– M2; F:AM 49283, right ramus with p4–m3, right p4, m1 broken, left p4, m1–m2, isolated incisor, isolated teeth, and ramal fragments; F:AM 49287, right ramus with p4–m2; F:AM 49290, isolated m1 broken, p4, c, i, deciduous premolars; F:AM 49288, left m1; F:AM 62796, partial skull; and F:AM 62797*, right maxilla with M2.

Near Wikieup, Big Sandy Formation (late Hemphillian), Mohave County, Arizona: F:AM 62990, right and left partial maxilla with P2, P4, M1–M2, right and left rami with c, p1–p4, m1–m2, m3 alveoli (fig. 20A–E), both partial humeri, both partial ulnae, partial radius, right and left metacarpals II– V (fig. 21G), two proximal phalanges, astragalus, and miscellaneous fragments; F:AM 72621, left isolated P4; F:AM 62991, left ramus with c (alveolus)–p2 (alveolus), p3–m1 and m2 broken; F:AM 62992, left ramus with c–m2 (p1 alveolus); F:AM 62994, left ramus with p4–m1 and alveoli; F:AM 62995*, left ramus with c, p1–p3 alveoli, p4 (broken)–m2, m3 alveolus; F:AM 62996, right ramus with p3–m2 and alveoli; F:AM 62997, left partial ramus with p4–m1; F:AM 63016D, left partial ramus with m1–m2; F:AM 63050, left m1; F:AM 63036*, right m1; F:AM 72622, left m1; F:AM 72623, left m1; F:AM 72608, left ramus with m2 and alveoli; F:AM 72550, partial left humerus (fig. 21A); F:AM 72651, right radius (fig. 22B); F:AM 72552, right ulna (fig. 21C–D); F:AM 72553, left femur (fig. 21E); F:AM 72578, incomplete metacarpal III; F:AM 72579, metacarpal V; F:AM 72580, associated metacarpals II, III, and V, Bird Bone Quarry (fig. 21H). F:AM 62998, left partial ramus with p1–M1 (p2 alveolus); F:AM 63052, right isolated m1, Clay Bank Quarry. F:AM 62993, right and left partial rami with p4–m2, stratum 3, Gray’s Ranch Quarry; and F:AM 72554, left tibia (fig. 21F), Horse Shoe Quarry.

Old Cabin Quarry, Quiburis Formation (late Hemphillian), Pima County, Arizona: F:AM 72655, right ramal fragment with m1 (broken)–m2; F:AM 50691, left ramus with c broken, p1 alveolus–m2 (p2–m1 broken); F:AM 50692, right partial ramus with c– m1, all broken; F:AM 50693, right partial ramus with p3–m2 (all broken); F:AM 50694, right partial ramus with p2–p3 both broken, p4, m1 broken; F:AM 75827, crushed skull with C–M2 (P1 alveolus, fig. 20E); F:AM 63089, skull with P3–M2; F:AM 75823, anterior portion of skull with P2, P4–M2, left ramus with m1–m3, right ramus with p4, m1 broken, right femur, left humerus; F:AM 72828, left and right maxillae with P4–M2; F:AM 50681, left maxilla with P3 (broken)– M2; F:AM 72664, left maxilla with M1–M2; F:AM 72824, left and right maxillae with C– M2; F:AM 75805, left and right rami with p2–m2 (fig. 20F–G); F:AM 75801, left and right partial rami with p2–m3; F:AM 75802, right ramus with p3–m1; F:AM 75803, right ramus with p3–m1; F:AM 50698, right m1; 75826, isolated right M1–M2; F:AM 50687, left P4 (broken)–M2; F:AM 75829, distal end left radius and calcanea; F:AM 75830, 75830a, left femur and two left tibiae; F:AM 75831, left metacarpals II–V, phalanx; F:AM 75832, right metacarpal IV; F:AM 62783, right radius: F:AM 62784, tibia, calcaneum, tarsals; and F:AM 62785, left metacarpal V.

Redington Quarry, Quiburus Formation (late Hemphillian), northwest of Redington, west side of San Pedro River Valley, Pima County, Arizona: F:AM 75800, right ramus with c–m2; F:AM 63099, right ramus with m1.

From the Quiburus Formation (late Hemphillian), Pima County, Arizona: F:AM 63080, right partial ramus with p1–m2 (m1 broken), Leach Dig, K mile west of Least Camel Quarry; and F:AM 72613, right partial ramus with p4–m2 all broken, Rogers Quarry.

Nichol’s Mine, upper Bone Valley Formation (late Hemphillian), Polk County, Florida: UF 23994*, right partial ramus with m1– m2.

Lava Mountains Fauna (late Clarendonian or early Hemphillian), Bedrock Springs Formation, San Bernardino County, California, USGS locality LM-16, USGS D669*: right and left rami of mandible with c, p1–4.

Yepomera (late Hemphillian), CIT locality 275, Chihuahua, Mexico: LACM 3534, left partial maxilla with P4 (broken)–M2 alveolus; LACM 30215, M1 broken parastyle.

Distribution: Possibly late Clarendonian of California; Early Hemphillian of Nebraska, Nevada, California, and Oregon; late Hemphillian of Oklahoma, Texas, New Mexico, Colorado, Nevada, Arizona, Florida, and northern Mexico.

Revised Diagnosis: Differs from V. vulpes of North America in anteroposteriorly short- er and less robust premolars; p4 often with second posterior cusp; m1 entoconid usually smaller relative to the hypoconid; talonid lacks transverse crest between entoconid and hypoconid, hypoconulid shelf smaller; m2 longer relative to length of m1 with anterolabial cingulum stronger and paraconid shelf larger; muzzle narrower; frontoparietal suture more anterior, with frontal crests joining at suture to form sagittal crest; braincase relatively narrower with frontal region much less expanded; small frontal sinus that penetrates base of postorbital process; and small bulla with less produced lip of auditory meatus.

Description and Comparison: A comparison of V. stenognathus with V. vulpes shows a few significant morphological differences in the lower dentition as indicated in the diagnosis. The premolars in V. stenognathus are anteroposteriorly shorter and less robust. Furthermore, a posterior cusplet is generally present on the p3 of V. stenognathus and the p4 often bears a second posterior cusp. In V. vulpes the posterior cusp on p3 and the second posterior cusp on p4 are generally absent and, if present, they are comparatively weaker than in V. stenog- nathus. The upper premolars of V. stenognathus closely resemble those of V. vulpes , including the lack of a posterior cusp on p3. The protocone of P4 tends to be smaller than that of the latter. No consistent morphological features were observed to distinguish the upper molars of V. stenognathus from those of the recent species, but on the whole these teeth appear to be larger relative to the size of the skull in V. stenognathus (compare P4 length and M2 width vs skull dimensions, fig. 22).

The shallow horizontal ramus is also similar to Vulpes vulpes , and the angular process is shallow and attenuated like that seen in living Vulpes species. A number of distinguishing features separate the lower molars of V. stenognathus from those of V. vulpes . Superficially the m1 of V. stenognathus resembles that of V. vulpes , but the talonid of V. stenognathus differs in that the entoconid tends to be smaller relative to the hypoconid and to lack the transverse crest that links it with the hypoconid that is often present in V. vulpes . The m1 hypoconulid shelf is also smaller than in V. vulpes . The m2 of V. stenognathus is larger relative to the length of the m1, with the anterolabial cingulum being stronger and the paraconid shelf larger than in V. vulpes .

The skull of V. stenognathus (F:AM 49284, fig. 19) is proportionally similar to that of V. vulpes except for a narrower (not altogether the result of lateral crushing) and somewhat shorter muzzle (fig. 22). The nasals are short, as in all Vulpes , and do not reach the transverse limb of the maxillary-frontal suture. The most distinctive features of the skull separating V. stenognathus from North American V. vulpes are correlated with the size and expansion of the braincase shown by the red fox (fig. 22). In V. stenognathus the width of the frontal shield is similar to that of V. vulpes , but the frontoparietal suture is located more anteriorly and thus the frontals are almost 20% shorter along the midline than those of similar-sized skulls of V. vulpes . Weak frontal crests join anteriorly near the frontoparietal suture to form a long, low sagittal crest in V. stenognathus , whereas in V. vulpes the crests join more posteriorly and thus form a shorter sagittal crest. The braincase of V. stenognathus is relatively smaller (see fig. 22) and less laterally expand- ed than in V. vulpes , and the frontal part of the braincase is markedly less expanded. An unexpected result of sectioning the postorbital region of this skull (fig. 57B) was the discovery of a small frontal sinus in the fossil form. Another skull fragment (F:AM 62796), also from Spring Valley, Nevada, shows this sinus as well. The sinus extends laterally into the base of the postorbital process. The nuchal crest is similar to that of V. vulpes and the shape of the entire occipital bone closely resembles that of V. vulpes except for its lower height relative to its width, which reflects the less expanded braincase of V. stenognathus .

Unfortunately the basicranial area of the Nevada skull (F:AM 49284; fig. 19) is badly broken, with the basioccipital missing, and only one broken bulla is present. As nearly as can be determined, the mastoid process, the paroccipital process, and the cranial foramina closely agree with those of V. vulpes . The broken bulla, however, has the lip of the external auditory meatus less produced than in V. vulpes , and this is confirmed by another crushed skull (F:AM 75827) referred to V. stenognathus from Arizona.

Isolated limb elements refered to V. stenognathus (fig. 21) also fail to show any morphological features to distinguish them from Vulpes vulpes . The proportions of foreto hindlimb elements (e.g., radius/tibia ratio) are within the range of living foxes. Metatarsal I is unknown in V. stenognathus , but its facet indicates that there was as short proximal rudiment that was smaller than the entocuneiform as in later species of Vulpes .

Discussion: Savage’s (1941) original description of Vulpes stenognathus was based on two partial rami and isolated teeth, which he concluded differed from recent Vulpes in their larger size, deeper horizontal ramus, and reduced accessory cusps on the premolars. Additional specimens from the type locality, as well as larger samples from other late Hemphillian localities here referred to V. stenognathus , do not fully confirm his observations. The measurements and statistics (appendices 2 and 3) for up to 64 dentitions of V. stenognathus and 53 specimens of V. vulpes from North America with a geograph- ical range from Alaska to Georgia show that the carnassials of the two species are nearly the same size, but the size of the other teeth differ. In V. stenognathus the mean values from the premolars and molars (except M1) are mostly smaller for the premolars and larger for the molars than those of V. vulpes . This is also indicated for the m1 mean in which V. stenognathus has nearly the same length as in V. vulpes and the confidence interval for the two taxa overlaps widely, whereas the m 2 in V. stenognathus is proportionally larger, with the confidence interval only narrowly overlapping that of V. vulpes .

The log-ratio diagram (fig. 22) shows that the skull measurements of V. stenognathus are, for the most part, within the range of those of the recent sample of V. vulpes . As described above, the most distinctive morphological features separating the skulls of V. stenognathus and V. vulpes are those correlated with the proportions of the muzzle and braincase.