Combining morphology and genetics in resolving taxonomy--a systematic revision of spined loaches (Genus Cobitis; Cypriniformes, Actinopterygii) in the Adriatic watershed.

Ivana Buj,Radek Šanda,Zoran Marčić,Milorad Mrakovčić,Marko Ćaleta,Michael Schubert

doi:10.1371/journal.pone.0099833

Ivana Buj, Radek Šanda + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0099833

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Journal: PloS one	Publication Date: Jun 11, 2014
Citations: 80	License type: CC BY 4.0

Affiliation: University of Zagreb, National Museum

Abstract

Taxonomic investigation of spined loaches from Dalmatia and Herzegovina was conducted on specimens from 14 localities. The results of the detailed morphological investigations were combined with genetic data (based on one mitochondrial and two nuclear genes) in order to resolve the taxonomic status of each Cobitis population. Among the investigated features of external morphology, the appearance of spots on the caudal fin base turned out to have the greatest diagnostic value. Furthermore, the number of branched fin rays enabled the discrimination of several species. No morphometric character alone could ensure determination of any Cobitis species. Nevertheless, groups of populations that are more similar in their body shapes correspond to mitochondrial phylogenetic lineages. Based on molecular genetic markers, Dalmatian and Herzegovinian spined loaches form independent lineages inside the Adriatic phylogenetic group. Mitochondrial DNA phylogenetic reconstruction revealed six monophyletic lineages, corresponding to six species distributed in the investigated area. The population distributed in Mostarsko blato karstic field in Bosnia and Herzegovina is described as a new species based on a unique combination of morphological characters: a single triangular Canestrini scale; usually 51/2 branched anal fin rays, 61/2 branched dorsal fin rays, 14 branched caudal fin rays; no spots in the surface pigmentation layer on the caudal fin base; scales on the body very small.

Highlights

Recognition and delimitation of species, the main objectives of systematics, are of crucial importance for implementation of adequate strategies for biodiversity conservation
The current taxonomic status of each population according to the literature is presented in the Introduction and in Figure 1, while taxonomic conclusions based on our results are reported in the Discussion and in the other figures
Males from Krenica and Matica were uniform with regard to length of dorsal (lD), lA, lV and lac, whilst those measures were significantly different between those males and those from Mostarsko blato

Summary

Introduction

Recognition and delimitation of species, the main objectives of systematics, are of crucial importance for implementation of adequate strategies for biodiversity conservation. Genetic data are frequently used to delimit species, when conclusions about species status are based on an exclusivity criterion, such as reciprocal monophyly or degree of genetic clustering [2], [3]. Those methods are subjective and fail to account for several phenomena that cause gene tree incongruence with species tree [1]. Some authors consider that integrative methods will not yield a clear result in cases when cryptic species are present [1], the critical review of the results of all mentioned methods may have the greatest resolution power in delimiting species, especially in cases when phenomena such as hybridization are more widespread, species are morphologically very similar and/or divergence happened more recently. Among such, ‘‘more difficult’’ taxonomic cases are freshwater spined loaches

Methods

Results

Conclusion