Molecular diversity ofGermany's freshwater fishes and lampreys assessed byDNAbarcoding

Abstract

This study represents the first comprehensive molecular assessment of freshwater fishes and lampreys from Germany. We analysed COI sequences for almost 80% of the species mentioned in the current German Red List. In total, 1056 DNA barcodes belonging to 92 species from all major drainages were used to (i) build a reliable DNA barcode reference library, (ii) test for phylogeographic patterns, (iii) check for the presence of barcode gaps between species and (iv) evaluate the performance of the barcode index number (BIN) system, available on the Barcode of Life Data Systems. For over 78% of all analysed species, DNA barcodes are a reliable means for identification, indicated by the presence of barcode gaps. An overlap between intra- and interspecific genetic distances was present in 19 species, six of which belong to the genus Coregonus. The Neighbour-Joining phenogram showed 60 nonoverlapping species clusters and three singleton species, which were related to 63 separate BIN numbers. Furthermore, Barbatula barbatula, Leucaspius delineatus, Phoxinus phoxinus and Squalius cephalus exhibited remarkable levels of cryptic diversity. In contrast, 11 clusters showed haplotype sharing, or low levels of divergence between species, hindering reliable identification. The analysis of our barcode library together with public data resulted in 89 BINs, of which 56% showed taxonomic conflicts. Most of these conflicts were caused by the use of synonymies, inadequate taxonomy or misidentifications. Moreover, our study increased the number of potential alien species in Germany from 14 to 21 and is therefore a valuable groundwork for further faunistic investigations.

Distribution of Eurasian minnows (Phoxinus: Cypriniformes) in the Western Balkans

“…However, recent barcoding of fishes in rivers Rhine and Weser indicated the existence of two divergent Phoxinus lineages (Knebelsberger et al, 2014). Moreover, the mixing zone of four lineages was detected in the same area in Germany .…”

Adding nuclear rhodopsin data where mitochondrial COI indicates discrepancies – can this marker help to explain conflicts in cyprinids?

“…In total, 193 specimens belonging to 14 cyprinid genera were included in this study. In eight genera (Acanthobrama, Alburnus, Chondrostoma, Gobio, Mirogrex, Phoxinus, Scardinius, Squalius) 'species groups' (in total 49 species) are present, exhibiting low interspecific divergence or haplotype sharing, or an introgression was suspected based on previous findings [10,12]. The labeonine cyprinids analysed comprise five genera (Crossocheilus, Hemigrammocapoeta, Tylognathus, Typhlogarra) with seven species, and eighteen species of the genus Garra.…”

“…The second focus of this study is on labeonine cyprinid genera, where members of Crossocheilus, Hemigrammocapoeta, barcoding proved to be a powerful and reliable tool for discriminating a large range of species, including all major taxa of marine as well as freshwater fishes [e.g. 1,[5][6][7][8][9][10][11][12]. The tool has gained additional attention among biologists by having the potential to reveal cryptic diversity, especially given the enormous amount of data collected globally, which can easily be used to compare own sequence data on a regional scale.…”

“…A high level of intraspecific mtCOI divergence is a likely indicator for cryptic diversity, i.e. putative new, or unrecognized species, pronounced phylogeographic structure, but might also result from introgressive hybridization [10][11][12][13][14][15].…”

“…Here, we focus on cyprinid species that exhibited low interspecific divergence, or haplotype sharing based on mtCOI data in previous studies [10,12]; these allow to critically assess the potential to resolve taxonomic conflicts as well as the discrimination capacity of the nuclear rhodopsin marker (ncRHO). Cyprinids are the most species-rich family of vertebrates in freshwaters of Eurasia, Africa, and North America [24,25].…”