Extraordinarily preserved talpids (Mammalia, Lipotyphla) and the evolution of fossoriality

Abstract

ABSTRACTWe describe four exceptionally preserved Miocene talpid specimens from Germany (representing Mygalea jaegeri, Proscapanus sansaniensis, and Geotrypus montisasini), expanding and amending the original descriptions based on micro-computed tomography (μ-CT) data. These specimens are scored into an enlarged version of the Sánchez-Villagra et al. (2006) character set, along with newly collected data for extant talpids and the fossil species Geotrypus antiquus, Domninoides mimicus, Eotalpa belgica, and E. anglica. The extant genus Scaptonyx is here resolved as the sister taxon to the American shrew-mole, Neurotrichus, and not as a close relative of the Talpini. Of the fossil talpids, Mygalea jaegeri is recovered as the sister taxon of extant desmans only in the context of genetic constraints: morphological data alone suggest that it represents a shrew-mole/desman-grade animal. Proscapanus sansaniensis is placed at the base of the Scalopini, whereas Domninoides mimicus is the sister taxon to Parascalops and Scapanulus. Geotrypus represents an early fossorial form, with G. antiquus retaining its position at the base of the Talpini, although G. montisasini's placement remains uncertain. Interestingly, the placement of these fossils causes character states more commonly associated with the semi-fossorial shrew-moles to be optimized to the root of the highly fossorial Talpini. Thus, despite the close relationship between Talpini and Scalopini based on morphological data, the fossil record provides evidence to support the independent evolution of extreme fossoriality in these groups. This finding is in agreement with genetic data sets, despite obvious topological differences.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP