Nyctereutes megamastoides (Pomel, 1842)

Nyctereutes megamastoides (Pomel, 1842)

Type locality: Perrier-Les Etouaires , France .

Age of the type locality: Late Pliocene, MN 16 .

Description. The remains belong to two adult individuals.

Upper teeth. The paracone and the metacone of the right M1 (ZIN 34171–1, L=10.0 mm; W= 12.7 mm) are partly destroyed, but equal in size; the protocone is large; the protoconule is evident ( Fig. 1A). The hypocone has a large base and is separated from the lingual cingulum by a small furrow.The cingulum is strong on the buccal and on the mesial sides. The small fragment of the second right M1 (ZIN 34171–4) is too small for any precise description.The left M2 (ZIN 34171–2, W= 8.4 mm) possesses a larger paracone compared to the metacone, a large protocone and smaller protoconule and metaconule ( Fig. 1B). The tooth is slightly damaged (part of enamel on the distal wall of the metacone is missing; the reconstructed M2 length is approximately 7.0 mm). Lingually, there is a cingulum-like hypocone. The left C1 (ZIN 34171–5, L=6.0 mm; W= 4.5 mm) is broken, and considerably compressed buccolingually ( Fig. 1C).

Right hemimandible. The specimen ZIN 34171–3 ( Fig. 1D, E and F) is not complete.The m3 (L= 4.1 mm; W= 3.7 mm), the m2 (L=8.0 mm; W= 5.6 mm) and part of the m1 (Wtal = 6.1mm) are the only teeth present. The mandibular thickness (on m1) is 6.8 mm. In occlusal view, the lower tooth row appears straight. The masseteric fossa is relatively deep. The m1 talonid has a simplified structure; the hypoconid and entoconid are large (with hardly any difference in height between them). The apices of the hypoconid and entoconid are locat- ed on the same transverse axis. Between the metaconid and entoconid, there is one accessory cuspid. The m2 is bean-shaped in occlusal view, with a conspicuous mesiobuccal cingulid ( Fig. 1F). The protoconid and metaconid are large and almost equal in size. On the talonid, there is a large hypoconid and a medium-sized metaconid. In occlusal view, the m3 appears oval.

Right ulna. The specimen ZIN 34171–6 is not complete. The lateral coronoid process is greatly reduced in comparison to the medial one ( Fig. 1G). The medial coronoid process is rather thin and compressed mediolaterally instead of expanding medially. The greatest breadth across the coronoid process is 16.6 mm.