Genus Pachynolophus Pomel, 1847

TYPE SPECIES. — Pachynolophus duvali Pomel, 1847 by original designation.

INCLUDED SPECIES. — Pa. cesserasicus Gervais, 1849; Pa. cayluxi (Filhol, 1888); Pa. livinierensis Savage, Russell & Louis, 1965; Pa. garimondi Remy, 1967; Pa. boixedatensis Crusafont & Remy, 1970; Pa. lavocati Remy, 1972; Pa. bretovensis Remy, 1988; Pa. molipontiensis Checa-Soler, 1994; Pa. zambranensis Badiola, Pereda-Suberbiola & Cuesta, 2005; Pa. eulaliensis Danilo, Remy, Vianey-Liaud, Marandat, Sudre & Lihoreau, 2013; Pa. gaytei Remy, 2015.

EXCLUDED SPECIES. — Pachynolophus hookeri Hooker, 1994 (synonym of Cymbalophus hookeri Godinot, 1987; see Danilo et al. 2013).

EMENDED DIAGNOSIS (after Danilo et al. 2013). — Small brachyodont equoids; nasal notch opening above the postcanine diastema, close to canine; confluent foramen ovale and middle lacerate foramen. Usually rather long DPC. Virtually complete set of cheek teeth with occasional lost of P1/ 1 in old individuals. Less bunodont dentition than in hyracotheres, up to fully lophodont. Mesostyle missing on upper molars, sometimes replaced by a “pseudomesostyle”. Fairly developed conules. Generally weak cingula, less continuous and less high than in hyracotheres, phyletically tending to fade; the labial one frequently interrupted at paracone on upper molars. Non-molariform premolars with phylogenetic trend toward a reduction of their area relatively to molars. P3/-P4/ devoid of hypocone. Postero-lingual expansion of the distal outline of P4/ in some species. Twinned metaconid on lower molars. Large hypoconulid basin on M/3, with labial cristid of hypoconulid directed from entoconid to mid hypolophid. P/3-P/4 devoid of entoconid.

NOTE

Occasional absence of the first premolar on some specimens (e.g. FSL 3038 [ Pa. livinierensis], ICP 3070 [ Pa. boixedatensis]) could be ontogenetic in origin. This phenomenon was also observed in the genus Plagiolophus that bears relatively short premolar series like Pachynolophus (Remy 2004: 123) . Indeed, many specimens of various Pachynolophus species retain their P1/1, what may be the original condition (e.g. Pa. cesserasicus FSL 2977, Pa. duvali MNHN CGR-82, Pa. lavocati MNHN Qu-7371, Pa. eulaliensis UM-SEL 45, SEL 88, SEL 05, an unpublished skull of Pa. livinierensis in the Vidalenc’ coll.).