METOREODON 



207 



metastylid of M 3 is not in line with the inner edge of the tooth. Likewise it differs from Prono- 

 motherium in that the metastylid is bent more outward and the molars are wider in proportion to 

 length. From Mesoreodon it differs in the greater length of M 2 and M 3 in proportion to Mi, and 

 these teeth are narrower. The stylids are larger on M 3 in Mesoreodon, and the metastylid is in 

 line. In Ticholeftus the protoconid is as large as or larger than the hypoconid in most of the species, 

 Mo and M 3 do not meet on a line, M 3 is much shorter in relation to Mi and M 2 , and the teeth 

 are narrower. 



The tooth proportions of Metoreodon fit those of M.? medius. In the two genera {Metoreodon 

 and Merychyus) the teeth are equally hypsodont and the hypoconids are larger than the protoconids. 

 The chief difference is that the metastylid in M.? medius is a trifle more outwardly directed. There 

 is a small tubercle at the base between the protoconids and the hypoconids in both. 



A fragment of the skull of a young animal, described by Leidy, had a moderately short sagittal 

 crest, long forehead, strong postorbital bar, deep malar, large antorbital fossa, abruptly depressed 

 frontals and nasals just back of the root of the nose, postglenoid process very thin anteroposteriorly 

 and linguiform, infraorbital foramen over P 4 , and supraorbital foramina rather far apart — all char- 

 acteristics of Metoreodon. In size this species comes nearest to M. -projectus but is smaller. 



Peterson (1906, pp. 65-66) described some fragmentary material consisting of parts of skulls 

 and lower jaws, Cat. Nos. 10+9, 1337, and 1411 CM., which he referred to Merychyus medius. 

 I regard these as belonging in the genus Tichole-ptus and nearest to T. brachymelis Douglass. The 

 molar-premolar index is 0.81-0.84, while in Metoreodon it is 0.66, and the distinctive characters of 

 the skull that can be made out are all within the Tkholeftus genus. 



Fig. 149. — Metoreodon novomexicanus (Frick). Fragmentary skull. CT. Cat. No. 32050 A.M.N.H. 2/3 nat. size. 



Metoreodon novomexicanus (Frick) 1929 

 Figs. 149-151; PI. XXXI, fig. 2 



Original Reference: Childs Frick Tertiary-Quaternary Explorations, 1928. Nat. Hist., XXIX, p. 107 

 {Merychyus medius race novomexicanus n. r.). 



Type Locality: Near Santa Cruz (skull) and on Skull Ridge, near Espaiiola (jaw), Santa Fe County, 

 New Mexico. 



Geologic Horizon: Lower Pliocene (Santa Fe). 



Types: Cotypes, Cat. No. 32050 A.M.N.H., palate of fully mature individual, with complete dentition; 

 and Cat. No. 32051 A.M.N.H., nearly complete lower right ramus with all teeth complete, except first two 

 incisors. This is a moderately old individual. 



Specific Characters: The skull is apparently slightly smaller than that of M. major, basing 

 this opinion on the relative sizes of the comparable teeth in the two species. It is decidedly wide and 

 heavy. The anterior narial opening is well back over P 3 . The infraorbital foramen is double, with 

 both openings above P 4 . 



