Ceratotherium neumayri Osborn, 1900

Geraads, Denis, Spassov, Nikolaï, Hristova, Latinka, Markov, Georgi N. & Tzankov, Tzanko, 2011, Upper Miocene mammals from Strumyani, South-Western Bulgaria, Geodiversitas 33 (3), pp. 451-484 : 460-461

Ceratotherium neumayri Osborn, 1900

FM-2468 is a mandible that can easily be distinguished from that of Dihoplus by its strongly convex ventral border and complete lack of incisors ( Geraads & Spassov 2009). The anterior border of the ascending ramus is more inclined than in Diceros bicornis (Linnaeus, 1758) , a correlate of the less forwardly inclined occipital than in this species. Another mandible, FM-2800, previously undescribed, lacks most of the rami, but is otherwise similar to the previous one: not very large, but robust, with deep and convex ventral border. The spade-like symphysis is somewhat damaged but clearly lacked incisors. Measurements are given in Table 2.

In Bulgaria, the only other occurrence of this species is at Kalimantsi, but it has a good record in the Late Vallesian and Turolian of the Eastern Mediterranean ( Geraads 1988, 1994; Giaourtsakis 2003; Giaourtsakis et al. 2006; Geraads & Spassov 2009). Antoine & Saraç (2005) accepted the idea of a size increase during the Turolian, although it rests upon scant evidence. The material from Str-2 is not particularly large, as most post-cranial measurements are within the range of the modern C. simum ( Guérin 1980) ; therefore, it gives no clear biochronological indication.

Some rhino limb bones, especially metapodials, could belong to either of the two large horned species present at Strumyani. From Str-1, there is a Mc II FM-2236 (L = 159; proximal APD = 51.6, dist. transverse diameter = 40.4) with a curved magnum facet and a short palmar tuberosity more like C. neumayri , and from Str-2 there are some metapodials including a Mc II with a straighter facet and a longer palmar tuberosity. None of these clearly match either of the two types recognized by Geraads (1988) at Pikermi, and we prefer not to attempt identification .

Measurements of some other bones: Uncinate FM-2234 (Str-1): L max. = 93.7; anat. L = 70. Uncinate FM-2771: L max. = 102; anat. L = 86.5. Astragalus FM-2167 is broad, with a shallow trochlea; Max.TD ≈95.7; Max. dist. TD ≈83; max. TD of trochlea = 89; H ≈86. Dist. humerus FM-2290: max. W = 182 mm; dist. articular W = 113. MC III FM-2237: W of shaft ≈65; prox. W = 68.4. MC III FM-2215-A: W of shaft = 67; prox. W = 69.7. MT III FM-2420: prox. W = 62; dist. articular W = 56.