﻿Surprisingly high genetic divergence of the mitochondrial DNA barcode fragment (COI) within Central European woodlice species (Crustacea, Isopoda, Oniscidea).

Michael J Raupach,Jörg Spelda,Björn Rulik

doi:10.3897/zookeys.1082.69851

Abstract

DNA barcoding has become the most popular approach for species identification in recent years. As part of the German Barcode of Life project, the first DNA barcode library for terrestrial and freshwater isopods from Germany is presented. The analyzed barcode library included 38 terrestrial (78% of the documented species of Germany) and five freshwater (63%) species. A total of 513 new barcodes was generated and 518 DNA barcodes were analyzed. This analysis revealed surprisingly high intraspecific genetic distances for numerous species, with a maximum of 29.4% for Platyarthrushoffmannseggii Brandt, 1833. The number of BINs per species ranged from one (32 species, 68%) to a maximum of six for Trachelipusrathkii (Brandt, 1833). In spite of such high intraspecific variability, interspecific distances with values between 12.6% and 29.8% allowed a valid species assignment of all analyzed isopods. The observed high intraspecific distances presumably result from phylogeographic events, Wolbachia infections, atypical mitochondrial DNAs, heteroplasmy, or various combinations of these factors. Our study represents the first step in generating an extensive reference library of DNA barcodes for terrestrial and freshwater isopods for future molecular biodiversity assessment studies.

Highlights

Isopods are a highly diverse group of invertebrates, with more than 10,300 species described to date (Boyko et al 2008; Poore 2012)
The observed high intraspecific distances presumably result from phylogeographic events, Wolbachia infections, atypical mitochondrial DNAs, heteroplasmy, or various combinations of these factors
Our study represents the first step in generating an extensive reference library of DNA barcodes for terrestrial and freshwater isopods for future molecular biodiversity assessment studies

Summary

Introduction

Isopods are a highly diverse group of invertebrates, with more than 10,300 species described to date (Boyko et al 2008; Poore 2012). Based on the dorsal surface of their exoskeleton, various other morphological traits as well as ecological strategies and behavior, woodlice can be roughly categorized in three main groups (Schmalfuss 1984; Hornung 2011): i) the runners, characterized with an elongate, slightly convex body and long pereopods (e.g., Philoscia Latreille, 1804), ii) the clingers, with a flat broad body and short but strong pereopods (e.g., Platyarthrus Brandt, 1833), and iii) the rollers, with a highly convex body able to roll up into a ball (pill bugs) (e.g., Armadillidium Brandt, 1833) (Fig. 1) Whereas their dispersion ability is rather limited, woodlice are found in almost all biomes of the world except the poles and high mountain ranges (Hornung 2011; Sfenthourakis and Taiti 2015). For Germany, 49 species of terrestrial and eight species of freshwater isopods are reported so far (Grünwald 2016)

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