Alternative combinations: Griphippus gratus, Hipparion gratum, Hippotherium gratum, Nannippus gratus, Neohipparion gratum
Synonyms: Nannippus niobrarensis Gidley 1906, Neohipparion niobrarense Gidley 1906, Protohippus niobrariensis Gidley 1906
See also Cope 1889, Cope 1893, Dalquest et al. 1996, Dalquest and Hughes 1966, Gidley 1907, Gregory 1942, Hay 1902, Hibbard 1941, Johnston 1938, Kelly and Lander 1988, Macdonald 1960, Macdonald 1992, Matthew 1909, McGrew and Meade 1938, Osborn 1918, Quinn 1955, Skinner and Hibbard 1972, Stirton 1940, Voorhies 1990, Webb 1969 and Webb and Hulbert 1986
Subtaxa: Hipparion gratum tehonense
- Pseudhipparion gratum: USNM 587, a set of teeth (A right upper premolar, p2, associated with two others, ?m2 and m3)
- Neohipparion niobrarense: AMNH 10828, a partial skull (Anterior portion of skull with lower jaws). Its type locality is Fort Niobrara, which is in a Barstovian terrestrial horizon in the Valentine Formation of Nebraska.
• Miocene to Pliocene of United States (1: Oklahoma collection)
Total: 48 collections each including a single occurrence
Specimen images are retrieved through the ePANDDA API.
Click image to enlarge. Click to access iDigBio record.