PALEOCENE MAMMALS OF CENTRAL UTAH — GAZIN 



21 



Speoific characters. — 'Size near Oxyclaenus simplex. Talonid of 

 M2 relatively wide. Paraconid directed forward and more distinct 

 from protoconid and metaconid. M3 unreduced. 



Description. — Several lower jaw fragments from the Dragon hori- 

 zon represent a species of Oxyclaenus near 0. simplex. Mo in the 

 type specimen, No. 16186 (fig. 12), from the upper or Dragon level 

 at the new locality in the western part of the canyon is about the 

 same size as the single lower 

 molar belonging with the type 

 of 0. simplex.; being smaller and 

 not so high crowned as in Oxy- 

 claenus cuspidatus. It differs 

 from O. simplex principally in 

 having a wider talonid portion 

 and a narrower trigonid, some- 

 what as in Loxoloplius but with 

 the talonid basin more open in- 

 ternally; however, the teeth are 

 relatively slender and exhibit a 

 well-defined external cingulum as 

 in Oxyclaenus. The paraconid is 

 directed more forward than in 

 Oxyclaenus and separated from 

 both the protoconid and metaco- 

 nid by a more distinct notch. 



M3 in the type exhibits a trigo- 

 nid portion much as in Mo, but 

 the tooth is fully as large as M2, 

 not showing the reduction seen in Puerco specimens referred to O. 

 simplex (Amer. Mus. Nat. Hist. No. 16347) and O. cuspidatus (Amer. 

 Mus. Nat. Hist. No. 16316). 



An upper molar fragment. No. 15736, which includes only the in- 

 ner portion may represent this form, and is characterized by a 

 prominent lingually placed hypocone and an equivalent protostyle 

 symmetrically placed. 



The anteroposterior diameters of M2 and M3 in No. 16186 are 

 5.7 and 6.0 nun., respectively. The transverse diameters are 4.1 and 

 3.6 mm. 



OXYCLAENUS species 



A single upper molar. No. 16217, in the material from the Wagon- 

 road level, is seen to correspond closely to M^ in the type of Oxy- 

 claenus simplex and may possibly represent 0. pearcei., the species 

 described from the Dragon horizon. The tooth differs from M^ of 

 O. simplex only in being slightly narrower transversely and in hav- 



FiGURE 12. — Oxyclaenus pearcei, new spe- 

 cies: Right ramus of mandible with 

 M2-M3 (U.S.N.M. No. 16186), type 

 specimen, lateral and occlusal views; 

 X 3, Dragon Paleocene, Utah. 



