In or Out of the Checklist? DNA Barcoding and Distribution Modelling Unveil a New Species of Crocidura Shrew for Italy

Emiliano Mori,Giuseppe Mazza,Mattia Brambilla,Fausto Ramazzotti,Giovanni Amori,Leonardo Ancillotto,Andrea Galimberti,Danilo Russo

doi:10.3390/d12100380

Abstract

The genus Crocidura (Eulipotyphla, Soricidae) is the most speciose genus amongst mammals, i.e., it includes the highest number of species. Different species are distinguished by skull morphology, which often prevents the identification of individuals in the field and limits research on these species’ ecology and biology. We combined species distribution models and molecular analyses to assess the distribution of cryptic Crocidura shrews in Italy, confirming the occurrence of the greater white-toothed shrew Crocidura russula in the northwest of the country. The molecular identification ascertained the species’ presence in two distinct Italian regions. Accordingly, species distribution modelling highlighted the occurrence of areas suitable for C. russula in the westernmost part of northern Italy. Our results confirm the role of Italy as a mammal hotspot in the Mediterranean; additionally, they also show the need to include C. russula in Italian faunal checklists. To conclude, we highlight the usefulness of combining different approaches to explore the presence of cryptic species outside their known ranges. Since the similar, smaller C. suaveolens may be displaced by the larger C. russula through competitive exclusion, the latter might be the species actually present where C. suaveolens had been reported previously. A comprehensive and detailed survey is therefore required to assess the current distribution of these species.

Highlights

Field identification at the species level may be problematic and unreliable for rodents and other small mammals, especially when species belonging to the same genus share similar morphologyDiversity 2020, 12, 380; doi:10.3390/d12100380 www.mdpi.com/journal/diversityDiversity 2020, 12, 380 and overlapping geographical ranges [1,2,3,4]
We provided the first evidence of the presence of C. russula on the Italian territory and reviewed, on such a basis, provided the first evidence of the presence of C. russula on the Italian territory and reviewed, on such a basis, the currently known distribution of Crocidura shrews occurring in Italy
We provided the first genetic evidence of the presence C. russula in Italy, near the

Summary

Introduction

Field identification at the species level may be problematic and unreliable for rodents and other small mammals, especially when species belonging to the same genus share similar morphology. C. suaveolens might be, a species complex and the Italian peninsula may host C. gueldenstaedtii mimula, further detailed molecular analyses are needed to clarify its taxonomic status [12,14] Another Crocidura species occurs in Mediterranean Europe, in regions that are close to the Italian borders, i.e., the greater white-toothed shrew C. russula. Given the resemblance between C. russula and C. suaveolens, as well as the morphological similarity, molecular analyses of field-collected individuals remain the only surefire method for species recognition and distribution assessment, at least in the overlap of their distribution ranges. Four individuals showing morphological features that match those reported for C. russula [20]

Materials and Methods

Locations originofofCrocidura

Species Distribution Modelling

DNA Barcoding Identification

Discussion