Urotrichus Temminck, 1841

Ziegler, Reinhard, 2003, Moles (Talpidae) from the late Middle Miocene of South Germany, Acta Palaeontologica Polonica 48 (4), pp. 617-648 : 634-635

Urotrichus Temminck, 1841

Type species: Urotrichus talpoides Temminck, 1841 .

? Urotrichus dolichochir ( Gaillard, 1899)

Fig. 8 .

Material and measurements.—Petersbuch 6: NHMA P6−1066, left dentary fragment with p4–m1 (trigonid), p4 (1.05×0.67), m1 Wa (1.03); NHMA P6−1067, right humerus, GL (7.60), Bp (3.64), BpwT (3.00), DS (1.30), Bd (3.86), BdwE (3.32), Bpx100/GL (48.0).

Description

Dentary.—There is only a short fragment of the horizontal ramus with two small mental foramina beneath the trigonid of m1 and a bigger one under the second alveolus anterior to p4. The third alveolus anterior to p4 is slightly inclined. This means that the fracture is near the real tip of the dentary and that the antemolar part is reduced. The cusp of the p4 is cone−shaped with a more or less flat lingual face and a postero−lingual crest. Close to the base of this crest there is a small accessory cuspule. The p4 is slightly heeled and has a precingulid and a postcingulid respectively. The m1 protoconid is somewhat higher than the p4. The paracristid is angular, the protocristid notched. The oblique cristid extends to below the protocristid notch and does not join the weak metacristid. There is a well−developed precingulid. The talonid is broken off.

Humerus.—The humerus is nearly complete. Only the epicondylar spines and the deltoid process are broken. It is slender in overall shape, which means only modest fossorial specialisation. Posteriorly the olecranon fossa is extensive, but shallow. The long axis of the head points latero−distally. The ridge running from the lesser tubercle to beneath the head is weak and curved. The brachialis fossa is moderately deep. Anteriorly the pectoral tubercle terminates far laterally about half way down the shaft. Teres tubercle and lesser tubercle are separated by a wide sulcus, head and greater tubercle by a deep and narrow notch. The supratrochlear fossa is wide and deeply pocketed. There is a deep notch between the trochlea and the fossa for the m. flexor digitorum profundus ligament.

Discussion

Dentary and humerus have been lumped together, because they match in overall size, both represent urotrichines and both are the only talpid leavings in the Petersbuch 6 talpid fauna. It is considered more probable that dentary and humerus represent only one species instead of two. The humerus shows undeniable urotrichine affinities and fits well with? Urotrichus dolichochir from La Grive in all morphological details and in gracility. The small size difference is not worth mentioning. The Petersbuch 6 specimen also resembles the humeri of? Urotrichus cf. dolichochir from Sandelzhausen (cf. Ziegler 2000: 81).

The type humerus from La Grive was named Scaptonyx? dolichochir by Gaillard (1899: 30) even though he noted the resemblance to the extant genus Urotrichus . As this species is not referable to Scaptonyx and in the absence of associated dental material Hutchison (1974: 226) referred the species tentatively to Urotrichus on the basis of the humeral morphology. He also considered the lectotype dentary of “ Scaptonyx ” edwardsi from the same site a possible candidate for the association with? Urotrichus dolichochir . However, Hutchison (1974: 228) also wrote that the dentary may belong with the humerus of cf. Scalopoides sp. from La Grive. In fact, we do not know the dentition of? Urotrichus dolichochir . The dentary fragment under study differs from Scaptonyx edwardsi in the duplication of the posterior mental foramen, in the presence of a postero−lingual cuspule on p4 and of a weak metacristid in m1. In order to resolve the problem whether any dentary belongs to any humerus, much more material is needed. In the present study both humerus and dentary are reservedly referred to? Urotrichus dolichochir . They represent the second record of this species in Germany.

Figures

Fig. 8.?Urotrichusdolichochir, Petersbuch 6. A. Left dentary fragment with p4 and m1−trigonid, NHMA P6−1066, buccal view; ca. × 10. B. Right humerus, NHMA P6−1067 in anterior (B1) and posterior (B2) views; ca. × 7.5.