Arvicolinae, Gray, 1821

Popov, Vasil V., 2004, Pliocene small mammals (Mammalia, Lipotyphla, Chiroptera, Lagomorpha, Rodentia) from Muselievo (North Bulgaria), Geodiversitas 26 (3), pp. 403-491 : 470

Arvicolinae gen. et sp. indet. ( Fig. 36 )

MATERIAL EXAMINED. — The vole molars, other than m1 and M3, indeterminable at species level, are described as if derived from a homogeneous sample. Having in mind the parallel evolution within particular vole lineages, the description of these molars may contribute in evaluating the overall evolutionary level of the vole assemblage in the locality. On the other hand, because the majority of the determinable molars belong to Dolomys occitanus , it can be supposed that the same is true for the other teeth. Hence, the descriptions presented below most probably should be referred to this species.

DESCRIPTION

All vole teeth lack crown-cementum and enamel differentiation.

M1: most teeth possess three roots. The enamel free areas at the sides of the crown are well pronounced, but they are low. The posterior dentine track is the highest. The occlusal surface consists of five, alternating and relatively well isolated dentine fields.

M2: the teeth have three roots. The occlusal surface consists of four dentine fields, anterior loop and three alternating triangles, of which the anterior two are more or less confluent with each other. The dentine tracks are low.

m2: the teeth possess two roots. The posterior one is concave in its lowermost part, indicating that it lies partly on the inner and partly on the outer side of the incisor (morphotype “ acrorhiza ”). The enamel free areas are generally low; the anterior one is the highest. The occlusal surface shows four alternating triangles, forming two pairs of largely confluent dentine fields (T4-T3 and T2-T1). The posterior loop is well separated.

m3: two roots and low dentine tracks. The occlusal surface consists of three dentine fields. The two anterior ones represent two pairs of opposite and widely communicating triangles (T4-T3 and T2-T1). The posterior root is also isolated.

Figures

FIG. 36. — Arvicolidae; A, left M1, Ms19, occlusal view; B, left M1, Ms20, occlusal view; C, right M2, Ms21, occlusal view; D, right M2, Ms22, occlusal view; E, right m2, Ms15, occlusal view; F, left m2, Ms16, occlusal view; G, left m3, Ms17, occlusal view; H, left m3, Ms18, occlusal view; I, left M1, Ms19, buccal view; J, right M2, Ms22, lingual view; K, left m2, Ms16, buccal view; L, right M2, Ms21, lingual view; M, left m3, Ms17, buccal view; N, left m3, Ms18, buccal view; O, right m2, Ms15, buccal view. Scale bar: 1 mm.