Miostrellus, RACHL, 1983

Rosina, Valentina V. & Rummel, Michael, 2017, The New Early Miocene Bat Records From The Molasse Sites Of South Germany, Fossil Imprint 73 (3 - 4), pp. 227-235 : 231

Miostrellus cf. risgoviensis RACHL, 1983

Text-fig. 1f , i–j

M a t e r i a l a n d m e a s u r e m e n t s. Forsthart, BSP 1959XXVII-Ch2 ( Text-fig. 1f ), the right M2 ca. 1.15 × ca. 1.55; BSP 1959 XXVII-Ch7 ( Text-fig. 1j ), the right C sup. ca. 0.83 × 0.65; BSP 1959 XXVII-Ch8 ( Text-fig. 1i ), the right C sup. 0.80 × 0.70.

D e s c r i p t i o n. The meso- and metastyle of the upper molar ( Text-fig. 1f ) are broken, and the area of the paraconule and preprotocrista is also damaged. The preprotocrista connects with the paracingulum; the postprotocrista extends to the lingual base of the metacone, and thus the trigon basin is closed. The crown has neither a hypocone nor a posterolingual talon.

The upper canines ( Text-fig. 1 i–j) are small and slender; the apexes are broken. The crowns are triangular in crosssection, shaped by a well-developed cingulum and show distinct posterior and lingual crests. The buccal crest and the anterior ridge are weak, so the anterolingual face and the anterobuccal ridge are seamlessly joined together into a single convex surface. The posterobuccal face is slightly concave. The posterolingual concavity is wide, but without the lingual talon.

C o m p a r i s o n. The shape of the M2 crown with a well-developed cingulum and the lack of the hypocone suggest that the tooth belongs to the vespertilionid bat. This specimen from Forsthart is almost identical with M2 of the holotype of M. risgoviensis ( BSP 1966 XXXIV703; Rachl 1983: 226, 229, tab. 52, fig. 70a) .

Due to the damage of the canine teeth, it is difficult to accurately judge the shape of their crowns. However, they undoubtedly belong to the vespertilionid bats. According to the triangular shapes in cross-section, and because of the lack of the lingual talons, the upper canines from Forsthart are most similar to those of M. risgoviensis (see, e.g., BSP 1966 XXXIV705; see also Rachl 1983: 229, fig. 70c). On the other hand, the Forsthart canines are similar to the upper canine from Rembach (cf. Vespertilio sp., BSP 1959 XXVIII630-2; Text-fig. 1b ) in having some expansion of the lingual cingulum. Nevertheless, due to the absence of the lingual talons in the canines from Forsthart, and the sharing of most of the above-listed morphological traits with M. risgoviensis, they are assigned to M. cf. risgoviensis. Moreover, they also correspond to it in size ( Rachl 1983: 226, tab. 52).

Figures

Text-fig. 1. a – cf. Hesperoptenus (sp. n.), right M1, BSP 1959 XXVIII630-1, Rembach, occlusal view; b – cf. Vespertilio (sp. n.), right C sup., BSP 1959XXVIII630-2, Rembach; c – Submyotodon petersbuchensis, fragment of right dentary with m3, BSP 1959 XXVIII630-3, Rembach, occlusal view; d – Miostrellus (sp. n.), left m3, BSP 1959 XXVII-Ch10, Forsthart, occlusal view; e – Miostrellus (sp. n.), right M1, BSP 1959 XXVII-Ch1, Forsthart, occlusal view; f – Miostrellus cf. risgoviensis, right M2, BSP 1959 XXVII-Ch2, Forsthart, occlusal view; g – Miostrellus (sp. n.), left M3, BSP 1959 XXVII-Ch3, Forsthart, occlusal view; h – Myotis sp., left m1, BSP 1959 XXVII-Ch9, Forsthart, occlusal view; i – Miostrellus cf. risgoviensis, right C sup., BSP 1959 XXVII- Ch8, Forsthart; j – M. cf. risgoviensis, right C sup., BSP 1959 XXVII-Ch7, Forsthart; k – cf. Miostrellus sp., right C sup., BSP 1959XXVII-Ch4, Forsthart; l – Myotis sp., left C sup., BSP 1959 XXVII-Ch5, Forsthart; m – Miostrellus (sp. n.), right C sup., BSP 1959 XXVII-Ch6, Forsthart; 1 – lingual view, 2 – occlusal view.