New distributional data for the Mediterranean medicinal leech Hirudo verbana Carena, 1820 (Hirudinea, Hirudinidae) in Italy, with a note on its feeding on amphibians

Federico Marrone,Simone Costa,Reinhard Gerecke,Enrico Schifani,Giuseppe Alfonso,Giacomo Bruni,Luca Vecchioni,Giuseppe Mazza,Pietro Brandmayr,Antonio Mazzei,Emiliano Mori,Mattia Menchetti,Rosario Barbagallo,Angelina Iannarelli,Fabio Stoch,Riccardo Novaga,Valerio Moretti,Marco Pecoraro,Giovanni Farina

doi:10.21426/b636052446

Abstract

Scarce data are currently available about the distribution of the Mediterranean medicinal leech Hirudo verbana in Italy, and most of the known occurrence localities are based on records collected in the nineteenth and the first half of the twentieth century, which were not confirmed in the last decades, mostly due to a lack of surveys. Accordingly, the available knowledge on the distribution of the species is far from being updated and representative, although a significant negative trend of H. verbana throughout the country is supposed. The lack of sound distribution data is a significant shortfall, which hinders the implementation of the monitoring of the species as required by the Article 17 of the “Habitats Directive” on the species of Union concern. To provide recent, validated distributional data for the Mediterranean medicinal leech in Italy to be used as baseline data for further surveys and monitoring, we present herein a set of unpublished observations collected in the last decades in peninsular Italy, Sicily, and Sardinia. Moreover, we report observation of H. verbana feeding on amphibians, a feeding habit to date poorly documented for the Mediterranean medicinal leech. Based on both published and novel data, H. verbana is characterised by a large but fragmented distribution in Italy. Therefore, dedicated monitoring programs and the collection of validated occasional observations are highly desirable to get a clearer picture of the real distribution of the species.

Highlights

Scarce data are currently available about the distribution of the Mediterranean medicinal leech Hirudo verbana in Italy, and most of the known occurrence localities are based on records collected in the nineteenth and the first half of the twentieth century, which were not confirmed in the last decades, mostly due to a lack of surveys
The lack of sound distribution data is a significant shortfall, which hinders the implementation of the monitoring of the species as required by the Article 17 of the “Habitats Directive” on the species of Union concern
To provide recent, validated distributional data for the Mediterranean medicinal leech in Italy to be used as baseline data for further surveys and monitoring, we present a set of unpublished observations collected in the last decades in peninsular Italy, Sicily, and Sardinia

Summary

Introduction

The Mediterranean medicinal leech Hirudo verbana Carena, 1820 is the only Italian leech included in the European “Habitats Directive” (EU Directive 92/43/CEE), where it is listed in Annex 5 sub Hirudo medicinalis Linnaeus, 1758 (i.e., the European medicinal leech). The scarcity of recent records and the lack of confirmation for most of the historical occurrence localities is generally ascribed to “a significantly (or rather, Biogeographia 36: a007 dramatically) negative trend” of the species throughout the country (Minelli 2006), the lack of targeted surveys of Hirudo verbana in Italy prevented obtaining an adequate picture of its current distribution, status, and trend

Methods

Results

Conclusion