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Chronologic history of the Daphoenictis hypodigm: 1937-1980

In 1950, paleontologist Raymond Alf and students from the Webb School, Claremont, California, explored Chadron Formation badlands northwest of Toadstool Park in the NW corner, SE1/4, sec. 5, T33N, R53W, Sioux County, Nebraska (Figure 2). Among the numerous Chadronian mammals collected was a partial hemimandible with cat-like dentition (UCMP 311018, previously UCR 11018), which at that time was referred to the felid “cf. Pseudaelurus ” (Hough and Alf, 1956). Also, two mandibular fragments with dentition (UCMP 311021, 311022, previously UCR 11021, 11022), representing this same carnivoran, were collected from Chadron Formation outcrops ~1 mile northwest of the previous locality in the SE1/4, sec. 31, T34N, R53W, but these were neither identified nor described.

A few additional specimens of this enigmatic cat-like species accumulated in Chadronian collections of the Frick Laboratory (AMNH) in the 1950s but failed to attract notice. A mandibular fragment with m2 and damaged m1 (F:AM 25242) was found by M.F. Skinner in 1953 at Brecht Ranch, southwest of Chadron, Nebraska. In 1958, a second mandibular fragment with m1 trigonid and m2-m3 (F:AM 76205) and a posterior cranium were collected in Chadronian White River beds at Flagstaff Rim, in central Wyoming, by Skinner, T. Galusha, R. J. Emry, and C. Elfgren. The cranium and mandibular fragment, found together, were given a common field number (BH28-650) and considered to belong to the same individual.

Identification of this carnivoran came about through publication of a hemimandible with p3-m2 (NMC 9205) recovered in 1937 from Chadronian deposits of the Cypress Hills, Saskatchewan (Russell, 1972). Russell assigned the jaw to the “canid” Daphoenus. Importantly, the molars of the Flagstaff Rim jaw and the teeth of the previously unrecognized jaw fragments from Nebraska were seen to match the intact teeth in Russell’s Cypress Hills jaw, and it was then discovered that the Flagstaff Rim cranium exhibited amphicyonid basicranial features (Hunt, 1974). As a result the fossils were assigned to a new genus and species, Daphoenictis tedfordi, and placed in the Amphicyonidae. The Cypress Hill jaw was designated the species holotype.

No upper teeth of this carnivoran were known until, in the early1970s, a high-altitude outlier of the White River Group in northwest Wyoming produced a Chadronian fauna (McKenna, 1972) that included a partial maxilla with a tall dagger-like P3 (AMNH 56351). This distinctive P3 was later recognized in another maxilla that preserved P3-M1 (USNM 214642) from Chadronian sediments at Flagstaff Rim. Because its upper teeth evidenced the trenchant form suggested by the lower dentition, the maxilla was referred to Daphoenictis (Emry and Hunt, 1980). These authors also included in Daphoenictis an unrecognized isolated m1 from Chadronian beds at Pipestone Springs (Main Locality), Montana, collected in 1948 (USNM 215031).

The intact hemimandible of Daphoenictis tedfordi (UNSM 27015) described in this report was discovered in 1962 near the locations in northwestern Nebraska where Raymond Alf collected the specimens in 1950 later referred to Daphoenictis. With the addition of UNSM 27015, the Chadronian badlands of the White River Group northwest of Toadstool Park become the principal geographic area yielding fossils of Daphoenictis. This district includes the Chadronian Raben Ranch local fauna preserving one of the few North American occurrences of latest Eocene multituberculates and other relict early Paleogene taxa (Ostrander, 1983, 1984, 1985).