Eumyarion medius (Lartet, 1851)

Hír, János & Kókay, József, 2010, A systematic study of the middle-late Miocene rodents and lagomorphs (Mammalia) of Felsőtárkány 3 / 8 and 3 / 10 (Northern Hungary) with stratigraphical relations, Geodiversitas 32 (2), pp. 307-329 : 321

Eumyarion medius (Lartet, 1851)

MATERIAL EXAMINED. — See Table 15 for data and measurements.

DESCRIPTION

On the M2, the lingual anterolophule is absent. The five main ridges are transverse and nearly parallel (anterolophule, protolophule, mesoloph, metalophule, posterolophule). Th e mesoloph exhibits intermediate development and the protolophule is inflated to form a cusp-like structure. The M3 has hypocone and metacone reduced and also reduced mesoloph, metalophule and posteroloph ridges. A strong axioloph is developed in the center of the crown. In lower molars, the metaconid and entoconid are higher than the protoconid and hypoconid. On the m1 the anteroconid is unicuspid with a bean-shaped occlusal surface. On the m1 the labial anterolophid is developed between the anteroconid and the base of the protoconid. Th e lingual anterolophid connects the anteroconid and the metaconid. The anterolophulid occurs between the lingual part of the anteroconid and the protoconid.

The metalophulid intersects the anterolophulid between the metaconid and the labial anterolophulid. Enamel ridges occur in the central region of the lower molars. The posterior arm of the protoconid is incipient in m1, and well developed in m2 and m3. The mesolophid is long and connected to the posterior base of the metaconid in m1, and extends to the ingual margin in m2 and m3. The posterior arm of the protoconid and mesolophid are merged in m2, but independent and parallel in m3. The ectomesolophid is short in m1, but absent in m2 and m3. The structure of the m1 from FT 3/8 is slightly different: in the anterior region only the anterolophulid and the posterior arm of the metaconid are well developed, no posterior connection of the anterolophulid towards the protoconid occurs because there is a notch in the anterior margin of the protoconid. The mesolophid and the posterior arm of the protoconid are merged.

COMMENTS

Detailed morphological analysis of the Eumyarion teeth from FF 2/3, FF 2/7 and FT 3/2 is given by Hír (2003, 2006). No significant differences have been found between the morphology and the dimensions of Eumyarion molars of Felsőtárkány 3/10 and the earlier published materials from the Felsőtárkány Basin. Th e occurrence of Eumyarion species in the Vallesian faunas of eastern Central Europe has been reported from Rudabánya (MN 9; E.latior (Schaub & Zapfe, 1953) in Kretzoi & Fejfar 2005), Götzendorf (MN 9; Eumyarion sp. in Rögl et al. 1993), Borsky Sväty Jur (MN 9; E. leemani (Hartenberger, 1965) in Sabol et al. 2004) and Belchatow A (MN 9; E. latior in Garapich 2002).

The dentition of Eumyarion species displays a high morphological variation, as previously mentioned by Engesser (1972), De Bruijn & Saraç (1991) and Bolliger (1994); this feature is also observed in the populations from the Felsőtárkány Basin.