MERYCHYUS 227 



Discussion: This species is apparently represented in the lower Snake Creek, for Matthew 

 (1924A, p. 182) recorded material from that horizon which seems to agree very closely with the 

 Merychyus dentition and which accords in size with M. elegans. 



Merychyus elegans paniensis Loomis 1924 

 Fig. 165 ; PI. XXXIV, fig. 4 



Original Reference: Miocene oreodonts in the American Museum. Bull. Amer. Mus. Nat. Hist., LI, 

 Art. 1, pp. 34-35, figs. 23, 24. 



Type Localities: Northeastern Colorado (HT, 9047, Martin Canon; PTs, 9045 and 9046, Cedar 

 Creek; PTs, 9442 and 9443, near Pawnee Buttes, Weld County). 



Geologic Horizon: Upper Miocene (Pawnee). Matthew (1901 A) listed M. elegans (the basis for the 

 above types) as found in the Pawnee Creek Loup Fork beds, which beds he considered to be "distinctly lower 

 than ... the Niobrara, Santa Fe, and especially the Republican River Basin . . . most nearly equivalent to the 

 upper beds of Smith Creek, Montana (Deep River sub-stage)." The fauna has subsequently proved these beds 

 to be equivalent to the lower Snake Creek. 



Types: Holotype, Cat. No. 9047 A.M.N.H., right lower jaw of an adult animal associated with metapodials 

 of both fore and hind feet and with other bones. Paratypes (all in A.M.N.H.), Cat. No. 9045, lower jaw, 

 with some limb material; Cat. No. 9046, nearly perfect fore foot; Cat. No. 9442, imperfect skull of young 

 individual; and Cat. No. 9443, good hind foot. Matthew considered No. 9047 as a male and No. 9045 a 

 female, the former being a somewhat younger individual than the latter. 



Specific Characters: This form is very similar to M. elegans (identified as such by 

 Matthew, 1901A). The immaturity of the skull prohibits comparison with the known comparable 

 parts of the type of M. elegans. 



A.M.9047 



Fig. 165. — Merychyus elegans faniensls Loomis. Mandible. HT. Cat. No. 9047 A.M. N.H. 1/2 nat. size. 



(After Loomis, 1924.) 



Mandible: The symphysis is almost straight vertically, the angle of the chin being about 37°. 

 The inferior edge slopes backward to a point beneath the last lobe of M 3 , whence it descends more 

 rapidly to the angle which is considerably more prominent than in M. elegans. The sigmoid notch 

 is wide open, and the condyle is very slightly convex. 



Dentition: Loomis describes the inferior teeth, in comparison with those of M. elegans, as 

 follows: 



While the length over all of the two premolar series is nearly the same, in M. faniensls the first lower 

 premolar is considerably smaller; premolar 2 is considerably larger; premolar 3 somewhat larger, and premolar 

 4 of about the same size. The whole dentition of M. -paniensis is lighter, both the premolars and the molars 

 being narrower. 



