Platygonus cf. marplatensis Reig, 1952

Gasparini, GermAEn M., Moreno-Mancilla, Oscar F. & Cómbita, JosØ L., 2021, Selenogonus narinoensis Stirton, 1947 (Tayassuidae, Cetartiodactyla, Mammalia): taxonomic status and paleobiogeographic implications, Fossil Record 24 (1), pp. 65-75 : 68

Platygonus cf. marplatensis Reig, 1952

Material examined

Portion of vertical ramus of a left hemimandible with m3 partially preserved ( Selenogonus narinoensis Stirton, 1947 , holotype MGN 931 ( IGM p002118)) ( Fig. 1a, b ) .

Occurrence

Dark-green fine-grained sandstone exposed in Cocha Verde, Toequerres highway, Tangua Municipality, Nariaeo Department, Colombia. Late Pliocene or Pleistocene (sic Stirton, 1947, p. 322) ( Fig. 2 ).

Description

This mandible corresponds to a large specimen. It has a shallow but sharply outlined masseteric fossa and a deep internal temporal fossa. The angular process projects forward to the middle part of m3, and its lower edge is slightly projecting laterally outwards. The lower border of the horizontal ramus is sharply hooked (accentuated) distally. The mandibular condyle is located behind the posterior edge of the vertical mandibular ramus. The coronoid process ascends behind m3.

The lower molar 3 only preserves the distal pair of main cusps (hypoconid and entoconid) and the third lobe, which has a well-developed single cusp, and a pair of smaller accessory cusps both located labially and lingually. Despite its incompleteness, a mesodont and bunolophodont dental morphology is observed.

Measurements

See Table 1.

Figures

Figure 1. Platygonus cf. marplatensis MGN 931 (IGM p002118). (a) Lateral view of the portion of vertical ramus of the left hemimandible; (b) m3 partially preserved. Platygonus marplatensis MMP-S Type 25. (c) Lateral view.

Figure 2. Geographical location of the MGN 931 (IGM p002118) and fossil records of Platygonus marplatensis in South America.