Myotis, KAUP, 1829

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 : 232

Myotis sp.

Text-fig. 1h, l

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 1959 XXVII-Ch9 ( Text-fig. 1h ), the left m1 1.30 × 0.67 × 0.80; BSP 1959 XXVII-Ch5 ( Text-fig. 1l ), the left C sup. 0.93 × 0.78.

D e s c r i p t i o n. The upper canine ( Text-fig. 1l ) is oval in cross-section, and has a well-developed cingulum. The lingual and buccal crests are very weak, and only the posterior crest is well developed. The posterolingual concavity is wide, but only slightly concave. The lingual talon is absent.

The first lower molar ( Text-fig. 1h ) is myotodont; the hypoconulid is well developed. The para- and metalophid are only somewhat curved. The metalophid is convex in the posterior direction, so that the tip of the metaconid is directed forward. The talonid is wider than the trigonid.

C o m p a r i s o n. The shape of the crown of the fossil upper canine from Forsthart corresponds most closely to type A of Menu (1985: 92, fig. 7). The posterolingual concavity of the crown is visibly developed; the area of the anterolingual face, the anterobuccal ridge and the posterobuccal face are seamlessly joined together into a single convex surface. These are the typical features of an upper canine of Myotis .

The upper canine from Forsthart is smaller than that of the Middle Miocene M. bavaricus from Petersbuch (MN 7–8, Germany; Ziegler 2003: 467, tab. 4), but slightly larger than that of the Middle Miocene M. murinoides from Sansan (MN 6, France; Baudelot 1972: 24), and further differs from it due to the lack of a strong buccal and lingual cingulum and the posterobuccal protuberances ( Baudelot 1972: 35, fig. 13). At the same time, the upper canine from Forsthart is appreciably smaller than those of M. aff. murinoides from Sandelzhausen (MN 5, specimen BSP 1959 II 7776: 1.11 × 0.94 × l.70; Ziegler 2000: 102). The fossil canine from Forsthart is most similar in size to some of the specimens of M. aff. murinoides (e.g., SMNS 45742.8; Ziegler 1994) from Stubersheim 3 (MN 3, Germany; Ziegler 1994: 104).

The para- and metalophids of the first lower molar from Forsthart are only somewhat curved, which is typical for the species of Myotis and Vespertilio . However, the metalophid of the Forsthart molar is convex in the posterior direction, so that the tip of the metaconid is directed forward instead of backwards, as with Vespertilio . In addition, the m1 from Forsthart is more slender then those of Miostrellus . On the basis of these morphological traits, the fossil m1 from Forsthart is also assigned to Myotis sp. The m1 from Forsthart is evidently smaller than those of the Middle Miocene M. bavaricus from Petersbuch (MN 7–8, Germany; Ziegler 2003: 467, tab. 4), as well as those of the Middle Miocene M. reductus from Petersbuch 6 ( Ziegler 2003: 474, tab. 6) and the Early Miocene M. cf. sanctialbani from Petersbuch 28 (MN 3, Germany; Rosina and Rummel 2012: tab. S1, supplementary data). At the same time, the m1 from Forsthart is appreciably larger than both those of the Middle Miocene M. ziegleri ( Baudelot 1972: 48) and the nominative species M. murinoides from Sansan ( Baudelot 1972: 24). It compares well in size with some specimens of M. aff. murinoides (e.g., SMNS 45742.1; Ziegler 1994: 104) from Stubersheim 3 and the Early Miocene M. aff. reductus from Petersbuch 28 and 62 ( Rosina and Rummel 2012: tab. S5, supplementary data).

R e m a r k s. Both the Early Miocene M. aff. murinoides from Stubersheim 3 and Wintershof-West (specimen BSP 1937 II 20417, = Vespertilionidae gen. et sp. indet.; Ziegler 1993, 1994: 106) and the M. aff. reductus from Petersbuch 28 are morphologically very close to each other ( Tab. 1; Ziegler 1993: 154, pl. 5, fig. 7, 1994: 107, pl. 3, figs 1–3, Rosina and Rummel 2012: 474, fig. 6 D–E). Both fossil forms are somewhat larger than the nominative M. murinoides from Sansan ( Tab. 1). It seems probable that the Early Miocene Myotis forms from Germany belong to the same taxon, which apparently differs from the M. murinoides from France. However, further morphological studies are needed for definitive conclusions that are beyond the scope of this paper.

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.