Hystricognathi, Brandt, 1855

Madozzo-Jaén, M. Carolina, Pérez, M. Encarnación, Montalvo, Claudia I. & Tomassini, Rodrigo L., 2018, Systematic review of Neocavia from the Neogene of Argentina: Phylogenetic and evolutionary implications, Acta Palaeontologica Polonica 63 (2), pp. 241-260 : 244

Hystricognathi Tullberg, 1899

Cavioidea Fischer de Waldheim, 1817 Caviidae Fischer de Waldheim, 1817 Caviinae Fischer de Waldheim, 1817 Genus Neocavia Kraglievich, 1932

Type species: Neocavia lozanoi Kraglievich, 1932 ; Andalhuala locality, Santa María Valley , Catamarca Province, Argentina, “Araucanense” late Miocene –early Pliocene ).

Emended diagnosis. —Cavioid diagnosed by the following unique combination of characters (synapomorphies marked with an asterisk): dental series anteriorly convergent; euhypsodont and double heart-shaped molariforms; presence of a constriction in the apex of each lobe; dentine crest in the middle of occlusal surface in each lobe; external secondary flex and primary internal flex present; hypoflexus/id funnel-shaped; cement present; enamel continuous around the entire crown, interrupted on the labial side in upper molariforms, and on the lingual side in lower molariforms, except in flexus/ids. *Molariforms posteriorly increase in size, differing from Microcavia , Cavia , Dolicavia , and Palaeocavia . The anterior lobe of the upper molariforms is anteroposteriorly smaller than the posterior lobe, and *has a round posterolabial extension that reaches the anterior margin of the posterior lobe, as in Microcavia and Dolicavia . Anterior lobe of lower premolars with absent, *incipient, or developed anterior projection. Presence of a groove for the passage of the infraorbital nerve in the maxilla, with its *lateral ridge less developed dorsoventrally than in Microcavia , Cavia , and Dolicavia . Palatine more dorsally located than the maxilla, forming a ridge in the palate, as in Microcavia and Dolicavia . The notch for the insertion of the tendon of the masseter medialis pars infraorbitalis muscle has a lateral ridge attached to a well-developed horizontal crest, as in other caviids; the mylohyoid crest is present; and the *lower incisor extends up to the level of the anterior lobe of the first molar.

Stratigraphic and geographic range.— Late Miocene–early Pliocene of Argentina: Andalhuala Formation, “Araucanense”, Santa Maria Valley in Andalhuala locality, Catamarca Province and Encalilla locality, Tucumán Province; Cerro Azul Formation, Caleufú locality, Rancul Department, La Pampa Province. Early Pliocene of Argentina: Monte Hermoso Formation, Farola Monte Hermoso locality, Buenos Aires Province ( Marshall and Patterson 1981; Strecker et al. 1989; Montalvo and Rocha 2003; Verzi et al. 2008; Tomassini et al. 2013 and references therein).