Basic info Taxonomic history Classification Relationships
Morphology Ecology and taphonomy External Literature Search Age range and collections

Calippus circulus

Mammalia - Perissodactyla - Equidae

Taxonomy
Pliohippus circulus was named by Quinn (1955). Its type specimen is BEG 31191-10, a set of teeth (wer right cheek tooth series with p4-m3), and it is a 3D body fossil. Its type locality is Sam Houston, which is in a Miocene terrestrial horizon in the Fleming Formation of Texas.

It was recombined as Merychippus circulus by Forsten (1975); it was recombined as Calippus (Grammohippus) circulus by Hulbert (1988); it was recombined as Calippus circulus by MacFadden (1998) and Kelly (1998).

Synonymy list
YearName and author
1955Pliohippus circulus Quinn p. 22
1975Merychippus circulus Forsten
1988Calippus (Grammohippus) circulus Hulbert, Jr. p. 256 fig. 14
1998Calippus circulus Kelly
1998Calippus circulus MacFadden p. 550

Is something missing? Join the Paleobiology Database and enter the data

RankNameAuthor
kingdomAnimalia()
Triploblastica
Nephrozoa
Deuterostomia
phylumChordataHaeckel 1847
OlfactoresJefferies 1991
subphylumVertebrata
Gnathostomata()
Osteichthyes()
Sarcopterygii
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda()
Reptiliomorpha
Anthracosauria
Batrachosauria()
Cotylosauria()
Amniota
Synapsida()
Therapsida()
RankNameAuthor
infraorderCynodontia()
Epicynodontia
infraorderEucynodontia
Probainognathia
Mammaliamorpha
Mammaliaformes
classMammalia
subclassTribosphenida()
infraclassEutheria()
Placentalia
orderPerissodactyla()
suborderLophodontomorpha
infraorderEuperissodactyla
Hippomorpha
superfamilyEquoidea
familyEquidae
subfamilyEquinaeSteinmann and Döderlein 1890
tribeEquini
genusCalippus()
speciescirculus()

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

Diagnosis
ReferenceDiagnosis
J. H. Quinn 1955Size smaller than Pliohip- pus supremus; teeth shorter crowned· metaconid and metastylid closely a;- pressed and symmetrically rounded; meta- conid larger than metastylid; flexids short; parastylid sloping across anterior face of teeth and for most part reduced to a scar; protoconid and hypoconid deep and strongly rounded on premolars, less so on molars; hypoconulid prominent on premolars and with a hypostylid fold; hypoconulid narrow, not pronounced, and without a hypostylid fold on the molars.
R. C. Hulbert 1988Cheekteeth with least unworn crown height of known species of the subgenus; unworn molar MSCH about 40 mm. Smaller than C. mmtini, with less complex fossettes, poorly developed pli caballins on premolars, and variable, often strong protostylids.