Phylogeny, phylogeography and hybridization of Caucasian barbels of the genusBarbus(Actinopterygii, Cyprinidae)

Abstract

The phylogenetic relationships and the phylogeography of seven species of Caucasian barbels of the genus Barbus s. str. were studied based on extended geographic coverage and the use of mtDNA and nDNA markers. Based on the 26 species studied, matrilineal phylogeny of the genus Barbus is composed of two clades: a) West European clade, and b) Central and East European clade. The latter comprises two subclades: b1) Balkanian subclade, and b2) Ponto-Caspian subclade, which includes 11 lineages mainly from Black and Caspian Sea drainages. Caucasian barbels are not monophyletic and are subdivided into two groups. The Black Sea group encompasses species from tributaries of the Black Sea, including the reinstalled B. rionicus, except for B. kubanicus. The Caspian group includes B. ciscaucasicus, B. cyri (with B. goktschaicus, which might be synonymized with B. cyri), B. lacerta from the Tigris-Euphrates basin and B. kubanicus from the Kuban basin. The genetic structure of Black Sea barbels was influenced by glaciation-deglaciation periods accompanied by freshwater phases, periods of migration and the colonization of Black Sea tributaries. Intra-and intergeneric hybridization among Caucasian barbines was revealed for the first time. In the present study, we report the discovery of B. escherichii in the Kuban basin, where only B. kubanicus was known to inhabit.Hybrids of these two species were detected based on both mtDNA and nDNA markers.Remarkably, the Kuban population of B. escherichii is distant to closely located conspecific populations, and we consider it as a relic. We reveal the intergeneric hybridization between evolutionary tetraploid (2n=100) B. goktschaicus and evolutionary hexaploid (2n=150) Capoeta sevangi in Lake Sevan.

Phylogeographic pattern, genetic diversity, and evolutionary history of the enigmatic freshwater fish species Aulopyge huegelii (Actinopterygii: Cyprinidae)

“…This divergence period is even older than proposed in some previous reports (Tsigenopoulos & Berrebi, 2000 estimated its divergence to the middle Miocene). On the other hand, Gante (2011) and Levin et al (2019) estimated the divergence of Aulopyge to 30 Myr, similar to the results obtained here.…”

“…A relaxed log normal clock was applied, which assumes that the substitution rates associated with each branch are independently drawn from a single, discretized lognormal distribution (Drummond et al, 2006). Calibration of the molecular clock was conducted using previously published data on divergence events within Barbinae (Gante, 2011) and on Barbus fossil evidence (Levin et al, 2019). Two splitting events in our phylogenetic tree were comparable with previously published phylogenies (Gante, 2011; Levin et al, 2019) and therefore suitable for use as calibration points: the origin of Barbus (18.5 ± 0.5 million years ago (Myr)) and the origin of Barbinae (42 ± 5 Myr).…”

“…Molecular studies including this taxon failed to provide clear answers, and results were affected by sampling and/or the phylogenetic analyses employed. Typically, Aulopyge was usually placed phylogenetically close with other European and Middle Eastern Barbinae genera (Gante, 2011; Levin et al, 2019; Machordom & Doadrio, 2001; Tsigenopoulos & Berrebi, 2000; Tsigenopoulos et al, 2002; Wang et al, 2013; Yang et al, 2015).…”

Parthenogenesis in Darevskia lizards: A rare outcome of common hybridization, not a common outcome of rare hybridization

“…2017; Levin et al. 2019). The evidence for widespread introgressive hybridization in Darevskia confirms the earlier expectations for frequent secondary contact throughout the evolution of this group.…”

The mitochondrial phylogeography of the Crimean endemic lizard Darevskia lindholmi (Sauria, Lacertidae): Hidden diversity in an isolated mountain system

“…The Late Pleistocene cooling in Crimea affected the biota to a more substantial extent than in the Caucasus, although no evidence of mountain glacier pres ence was found here (Vakhrushev and Amelichev 2001). Because of a limited scale and relatively simple topogra phy, along with longterm connections with the adjacent continent, Crimea acted as a "melting pot" rather than re fugia for biota (see Mendel et al 2008;Dufresnes et al 2016;Kukushkin et al 2018;Levin et al 2019). Thus, the level of endemism here is low, and unique genetic di versity (though only slightly different from the mainland populations) was detected only for few vertebrate species, especially reptiles (Fritz et al 2009;Zinenko et al 2015;Psonis et al 2017Psonis et al , 2018Jablonski et al 2019).…”