HIPPARION. 



I 89 



Hipparion gratum tehonense Merriam 1916. 

 Text Fig. 152. 



Ncokippurion gratum tehonense, n. subsp., Merriam, John C. "Mammalian Remains from the Chanac Formation of the Tejon 

 Hills, California," Univ. Cal. Publ. Bull. Dept. Geol. Vol. 10, No. 8, Dee. 23, 1916, pp. 118-124, figs, la, lb, lc. 



Horizon and locality. — Chanac formation, southern end of the San Joaquin valley, California. Of an early Pliocene 

 or latest Miocene phase. Type collected by J. P. Buwalda. 



Type. — Univ. Cal. Pal. Coll. 21780. A right superior molar, m 1 ?. 

 Type figure. — Text Fig. 152 of this Memoir. 



Characters. — (Merriam, 1910, p. 118) "This species corresponds approximately in size and form to Neohipparion 

 gratum of the Great Plains region. It is doubtfully distinguished from the typical form of that species by the tendency to 



la 



Fig. 152. Original figures of the type of Hipparion gratum tehonense Merriam, Univ. Cal. Pal. Coll. 21780, m 1 ?. 

 (la) Occlusal view; {lb) outer view; (lc) posterior view. Natural size. After Merriam, 1916, p. 119. 



show a more nearly circular cross-section of the protocone and by somewhat dubious characters in width of crown and 

 nature of the enamel folds bordering the fossettes." 



"The character of the protocone of the Chanac form (figs, la to lc) suggests Hipparion plicatile of the Alachua clays 

 of Florida, but the crowns in that species seem larger and relatively wider than in the Chanac species. //. ingenuum also 

 of the Alachua clays is not widely removed from the Chanac species, but the protocone is smaller. The Chanac species 

 differs from Neohipparion montezumae in its more nearly circular section of protocone and possibly in a tendency to rela- 

 tively greater transverse diameter of the fossettes." 



"The characters of the Chanac species represented by specimen 21780 [the type] are in general like those of Hipparion 

 mohavense of the Ricardo Pliocene, but they are shown in a form with smaller dimensions, and approaching the combina- 

 tion of characters of A T . gratum. The species is evidently very near the Great Plains form of N. gratum, and it is not impos- 

 sible that larger collections will exhibit a range of characters making even subspeeific separation inadvisable." 



Regarded by Merriam (1916, p. 118) as very near to Hipparion gratum Leidy. 



