Choerolophodon anatolicus Ozansoy, 1965

Geraads, Denis, Kaya, Tanju & Mayda, Serdar, 2005, Late Miocene large mammals from Yulafli, Thrace region, Turkey, and their biogeographic implications, Acta Palaeontologica Polonica 50 (3), pp. 523-544 : 528-529

Choerolophodon anatolicus Ozansoy, 1965

Type locality and age: Yassiören , Turkey, Vallesian, Miocene .

Material from Yulafl I.—TTMEU−CY−22, right dentary with m3 and alveolus of m2 ( Fig. 4C); TTMEU−CY−201, left dentary with m3; TTMEU−CY−32, isolated m3 ( Fig. 4D).

Description.—Both dentaries are morphologically similar and certainly belong to the same individual. The corpus is slender relative to that of Tetralophodon of the same locality ( Table 1); its depth slightly decreases posteriorly. The ventral border of the corpus is almost straight. The interalveolar crest is curved outward and slopes ventro−mesially, with an angle of about 25 ° relative to the alveolar border. The symphysis is broken, but extends distally as far as the mesial part of m2. The mandibular foramen, 25 mm in diameter, is located below the middle of m2. The mandibular canal lies along the corpus, small and square in section anteriorly, becoming broader and triangular posteriorly.

Heavy wear on TTMEU−CY−22 and TTMEU−CY−201 does not allow description of the structure of the conelets and accessory conules. Both m3s have five lophids and a small posterior cingulum with small conelets. The half−lophids of the third and fourth lophids are nearly fused to each other. The mesoconelets are located anterior to the main cones, contributing to an anteriorly−pointing “V” shape of the lophids in occlusal view, or “chevroning”. The fifth lophid is reduced in width and is composed of a main cusp and a small pretrite mesoconelet.

The m3 TTMEU−CY−32 has four lophids and a long talonid, which is composed of an irregular arrangement of four small conelets. Wear gradient is strong. It is certainly from a male individual (measurements: Table 1 and Fig. 7 ). On the pretrite side, the first two half−lophids are accompanied by posterior accessory conules, as on the specimen AS 92.605 from Sinap ( Sanders 2003). The fourth lophid has a double mesoconelet. The cement is weak at the base of the interlophids and well developed on the lingual and labial walls of the crown. The chevrons are well developed in the last three lophids. The teeth of Yulafli have well developed ptychodonty, but by contrast weak choerodonty.

Comparisons.—During the late Miocene, Choerolophodon was abundant in Turkey, contrasting with its less common occurrences in other Eurasian faunas. It has been recorded, among other sites, at Pikermi, Samos, Ravin de la Pluie in Greece, Veles in FYROM, Maragha in Iran, Ezerovo and Ahmatovo in Bulgaria ( Tassy 1983, 1989; Bakalov and Nikolov 1962, as Trilophodon angustidens ). The contemporaneous C. corrugatus is documented from Dhok Pathan and Nagri formations of the Siwalik ( Tassy 1983), while choerolophodonts span the middle to late Miocene in Kenya ( Tassy 1986; Pickford 2001). In Turkey, late Miocene Choerolophodon are known from Çorakyerler, Garkin, Kinik, Gülpinar, Gökdere, Kayadibi, upper and lower levels of Kemiklitepe, Eşme−Akçaköy, Ramiz in Istanbul, and Sinap ( Şenyürek 1952; Viret 1953; Ozansoy 1965; Gaziry 1976; Tassy 1994; Tassy et al. 1989; Sanders 2003). Moreover, a few middle Miocene Choerolophodon have been recorded in Turkey (e.g., Sofça) and Chios ( Gaziry 1976; Tobien 1980).

Turkish Choerolophodon are commonly assigned to Choerolophodon pentelici , except that from Sinap, which was assigned to C. anatolicus ( Ozansoy 1965) . Sanders (2003) also suggested that some other early samples of Choerolophodon (Eşme−Akçaköy, Kayadibi, Kemiklitepe−D and Gökdere) also belong to C. anatolicus , which would subsume C. pentelici lydiensis Tassy, Sen, Jaeger, Mazin, and Dalfes, 1989 . Ozansoy’s species would then range from the Vallesian to the early Turolian, subsequently replaced by C. pentelici at the end of the early Turolian (late MN11).

The fossils from Yulafli compare with those of C. anatolicus from Sinap described by Sanders (2003). They share a slight downward inclination of the symphyseal segment, simple crowns, a similar lophid formula, and weak expression of choerodonty. TTMEU−CY−32 closely resembles the m3 of C. anatolicus ( AS 92.605) from Sinap, except that, in our material, the ptychodonty is stronger and the cement is weaker. The molars of C. anatolicus from Eşme−Akçaköy ( Gaziry 1976: pl. 5), referred to his new subspecies C. pentelici lydiensis by Tassy (1989), differ from those of Yulafli by having well developed choerodonty, a moderately developed cement at the base of the interlophids, and a slightly smaller size ( Fig. 7 ), but the inclination of the mandibular rostrum is similar, and like TTMEU−CY−32 the mesoconelet of the third pretrite half−lophid remains isolated. The teeth from Yulafli are similar to those of Choerolophodon from Küçükçekmece (“ Mastodon sp. ” of Malik and Nafiz 1933: pls. 5, 6), and to a much worn m3 from Ramiz in Istanbul ( Viret 1953). The record of C. pentelici from the upper level of Kemiklitepe ( Tassy 1994: fig. 2) and Gökdere ( Senyürek 1952: fig. 6) is based upon deciduous teeth only. They have well developed choerodonty and ptychodonty and a complex occlusal pattern.

The m3s from Yulafli fall within the size ranges of C. pentelici , C. anatolicus , and also C. corrugatus ( Fig. 7 ), but the size of the cheek teeth appears to be less important than occlusal morphology, since there is much size overlap between species, partly because of sexual dimorphism ( Sanders 2003). The morphological characters of the Yulafli sample suggest an intermediate form showing more resemblance to C. anatolicus than to C. pentelici sensu stricto.

Figures

Fig. 7. Length versus width plot of Choerolophodon m3s.