Tapirus sp.

Holanda, Elizete C. & Rincón, Ascanio D., 2012, Tapirs from the Pleistocene of Venezuela, Acta Palaeontologica Polonica 57 (3), pp. 463-472 : 465-467

Tapirus sp.

Fig. 2A, B .

Material.— Incomplete right maxilla, OR1369; incomplete mandible, OR1367 from El Breal de Orocual , Monagas State ( Fig. 1 ), Plio−Pleistocene .

Description.—Maxilla: OR1369 is a juvenile bearing DP 2–4 in wear, as well as a fully erupted M1. In lateral view, P2 and P3 are preserved in crypt ( Fig. 2A, B ). Rincón et al. (2009) erroneously considered the deciduous teeth to be the P4–M3 of an adult individual.

DP2 is trapezoidal in shape and bears a small parastyle. The reduced protocone is located next to the hypocone, and is connected to the paracone by the base of the ectoloph. The protoloph is oriented obliquely relative to the ectoloph, and less transverse than the metaloph. DP3 is slightly trapezoidal and marked by a poorly developed parastyle. Its protoloph and metaloph are oriented transversely, with the former being wider than the latter. DP4 is more molariform than DP3 and shows less wear. As in DP3, the protoloph is wider than the metaloph, with both being oriented transversely. The DP4 parastyle is more developed than on DP2–3. All of the preserved deciduous teeth bear relatively poorly developed mesial and distal cingula. By contrast, labiodistal cingula are present and well developed on the cheek teeth. M1 presents no wear, and bears a well developed parastyle, as well as a mesial cingulum. The suture between the maxilla and the jugal is partially fused.

Mandible: OR1367 represents a partial mandible preserving the alveoli for i1–3, as well as the canines and the right dentary bearing p2–m 3 in situ ( Fig. 2B ). The mandibular symphysis is solidly fused and the bone is relatively slender. On the preserved cheek teeth, the lophids show little wear and lack accessory cuspids. The p2 and p3 are bent distolabially and mesolabially, respectively, and show wear. On p3–m3, cingulids are present and well developed mesially and distally, but absent labially and lingually. A small, but distinct, metastylid is present on the distolingual side of the metaconid on p3, m1, and m3. A better developed metastylid is present on m2 ( Fig. 2B 2 ).

Measurements.—OR1369: DP2L = 19.8; DP2W = 19.82; DP3L = 19.21; DP3W = 20.3; DP4L = 20; DP4W = 23; M1L = 22; M1W = 23.8. OR1367: see Table 1.

Remarks.—The mental foramen in OR1367 is located directly ventral to the p2, as in most species of Tapirus .While OR1369 and OR1367 resemble T. terrestris in size, the specimens are very slender. The presence of a well−developed metastylid on m2, as well as a small but distinct metastylid on p3, m1 and m3

http://dx.doi.org/10. 4202/app.2011.0001

in OR1367 differs from the condition in other extinct and extant South American species, in which it is usually absent. Among the North American species, a relatively well−developed metastylid frequently occurs on p4 and m 1–2 in T. johnsoni (e.g., F:AM 37302) and on the deciduous teeth of T. polkensis (Hulbert et al. 2009) , while being poorly developed or absent in T. webbi , T. veroensis , and T. haysii . However, while T. polkensis differs from other species of Tapirus , as well as OR1369 and OR1367, by its overall smaller size, T. johnsoni is distinguished by relatively short cheek tooth crowns bearing a moderately developed parastyle.

Figures

Fig. 2. Tapirus sp., El Breal de Orocual, Plio−Pleistocene. A. ORI369, right maxilla in lateral (A1) and occlusal (A2) views. B. ORI367, mandible in labial (B1) and occlusal (B2) views. Scale bars 30 mm.

Fig. 1. Map of the localities in Venezuela from which fossil tapirs have been reported.