In the foothill zone—Sabanejewia balcanica (Karaman 1922), in the lowland zone—Sabanejewia bulgarica (Drensky, 1928): Myth or reality?

Abstract

The status of golden loaches (genus Sabanejewia ) in the region of Central Europe and Balkans is still ambiguous. The greatest controversy is caused by species Sabanejewia balcanica and S. bulgarica . Both species are characterized by a wide spectrum of morphological variability and overlapping of distinguishing features, which then lead to difficulties in their determination. Previous phylogenetic studies aimed on the resolving of their taxonomic status did not include samples from their type localities and so led to a lack of their true distribution in this region. Therefore, the main aim of this study was to identify taxonomic status of golden loaches populations in the region of the middle Danube basin and adjacent areas on the model territory of Slovakia. For this purpose, we used novelty approach (morphological, molecular, and microhabitat) and we also included the missing samples from the type localities of both species. Based on mtDNA all the Slovakian samples reflected haplotype richness revealed on the type locality of S. bulgarica , although the genetic distances from other representatives of the genus Sabanejewia occurring are not significant. Within the morphology, we have revealed a great measure of variability in studied populations, which is largely caused by different habitat conditions and thus representing a phenotypic plasticity of these fish.

Increased spatial resolution of sampling in the Carpathian basin helps to understand the phylogeny of central European stream-dwelling gudgeons

“…These results suggest that studies conducted on Carpathian populations may significantly expand our knowledge about the phylogeny of other species and species complexes as well. Moreover, the recent note of Krizek et al [ 10 ] highlights that relevant taxonomic and phylogenetic findings can also be made by analyzing a limited number of individuals, if they are collected from the appropriate region, and if the newly-revealed phylogenetic information is analysed together with appropriately-selected data from the literature. In our case, despite the limited geographic range (~ 50′000 km 2 ) of the studied area, and the relatively low sample size, the low within-site genetic variability and the geographic distribution of the indicated haplotypes suggests that the results of our investigation provides reliable and relevant information about the phylogenetic features of gudgeons living in the study area.…”

“…that have not been revealed successfully by conventional (i.e. phenotype based) methods [5][6][7][8][9][10][11]. Results of these studies show that many hitherto widespread species have to be separated into a number distinct entities by their phylogenetic features.…”

Endangered spined loach Cobitis species in Southwest Germany: A complex network of native, hybrid and newly emerged populations

“…In our study, this feature enabled clear identification of C. bilineata, although some diploid individuals of C. elongatoides in the Odra and Elbe River catchment were shown to also have a second, less pronounced, ventral spot (Kotusz, 2008), underlining cautious use of such characters. Allometrics, and phenotypic plasticity among sampling sites, significantly affected the body shape of spined loaches, similar to two species of the closely related Sabanejewia genus, which suggests that habitat conditions influenced morphology (Križek et al, 2020). Nonetheless, individuals were accurately assigned to one of three maternal haplotypes using canonical variate analysis, but the number of samples was too low to differentiate true species and hybrids based on shape.…”

Morphological and genetic diversity of Sabanejewia balcanica (Cobitidae, Actinopterygii) in Bosnia and Herzegovina

“…Namely, Križek et al. (2020) described more pronounced morphological plasticity of Sabanejewia populations, explained by differences in habitat conditions. Our results indicate more pronounced morphological diversities only between populations that have been separated for longer period, as explained above.…”

“…Morphological and meristic characters, as well as genetic diversity of S. balcanica have been investigated in the waters of Danube basin in Croatia (Buj et al., 2008; Delić et al., 2003), Slovenia (Šumer & Povž, 2000), Czech Republic (Bartoňová et al., 2008; Križek et al., 2020), as well as from the western Balkan area (Marešová et al., 2011). The abovementioned investigations corroborated high level of morphological diversity and morphological plasticity of this species.…”