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[Aim] The afroalpine sky-islands present one of the most interesting models to study discrete biogeographic patterns in a terrestrial island system. Here, we performed range-wide sampling of the afroalpine clade of fine-leaved Festuca grasses and address a set of hypotheses on its origin and dispersal. We focus on the widespread species F. abyssinica and explore the role of the eastern and western African sky-islands., [Location] Tropical Africa, [Taxon] Afroalpine Festuca, [Methods] We combine data from field surveys, phylogeography, coalescence-based dispersal modelling, and environmental niche and dispersal costs analyses to infer patterns of genetic diversity, genealogical relationships, colonization routes and range shifts under two Quaternary climates (current – to represent warm periods; and Last Glacial Maximum (LGM) – to represent cold periods)., [Results] The westernmost populations in East Africa show higher genetic diversity and higher similarities with the West African populations and the Ethiopian Simen Mountains than with the more closely situated East African populations. Dispersal models and ecological niche predictions of F. abyssinica supported multiple long-distance dispersals (LDD) among the eastern African sky-islands, and at least two dispersal events between the two sides of Africa (0.86 Ma and 0.52 Ma), probably facilitated by bridging suitable habitats during the coldest periods of the Pleistocene., [Main conclusions] We reconstruct an afroalpine mountain-hopping dispersal model, with migrations occurring between adjacent sky-islands in eastern Africa, and through a Central Africa–Sudan pathway connecting afroalpine patches on the two sides of the continent., The work was supported by the Spanish MINECO CGL2012-39953-C02-01 and the Norwegian NUFU 2007/1058 grant projects to PC and CB respectively. MN was funded by a Spanish Ministry of Education postdoctoral contract in the University of Zaragoza, and PC and MN by a Bioflora research team A01-17 and A01-20R grants co-funded by the Spanish Aragón Government and the European Social Fund (FEDER 2014-2020; "Construyendo Europa desde Aragón").

The sterlet (Acipenser ruthenus Linnaeus, 1758) is a relatively small sturgeon widely distributed in Eurasian rivers from the Danube to the Yenisei. During the twentieth century, all wild sterlet populations have declined due to anthropogenic factors including: overfishing, poaching, construction of dams, and pollution. Despite the necessity of characterization both wild and captive stocks, few studies of population genetics have been performed thus far. Here we studied the genetic diversity and geographic structure of sterlet populations across the eastern range – Ob-Irtysh and Yenisei basins – by sequencing a 628-bp fragment of mitochondrial DNA control region. We identified 98 new haplotypes, delineated 12 haplogroups and estimated the time of basal haplogroup divergence within the species as over 8 million years ago. Our data suggest that Ob-Irtysh and Yenisei populations are isolated from each other and much lower genetic diversity is present in the Yenisei population than in the Ob-Irtysh population. Our data imply that sterlet populations in Siberian rivers underwent bottleneck or fragmentation, followed by subsequent population expansion. The data obtained here are important for sterlet population monitoring and restocking management.

The genus Rutilus is a widely distributed lineage of cyprinids and ranges from West Europe to East Siberia. Although matrilineal phylogeny and phylogeography of western species were already studied, roaches from remaining part of the range were not examined. Phylogenetic analysis based on cytochrome b sequences detected the following three major phylogenetic clades: (i) R. frisii, (ii) R. rutilus s. str., and (iii) group of six Ponto–Caspian taxa: R. caspicus, R. heckelii, R. rutilus aralensis, R. rutilus lacustris, R. schelkovnikovi, and R. stoumboudae. Our results suggest that these “species” within Ponto–Caspian clade could be a single species (R. lacustris by priority of description). The Ponto–Caspian clade is most widely distributed among others and covers the freshwaters from the Aegean Sea basin to Laptev Sea tributaries. Both R. rutilus s. str. and Ponto–Caspian clades sympatrically occur in Black Sea and Caspian Sea basins, Azov Sea itself, and even in drainage of White Sea. The vastest zone of contact (approximately 1700 km) was detected in the Volga basin. The spatial pattern of haplotype diversity and the shape of haplotype network argued for multiple refugia in Ponto–Caspian region as well as a rapid post-glacial colonization of Volga River and Siberia.

Phylogenetic analysis using mitochondrial and nuclear DNA markers showed that the Least Cisco gradually spread from Siberia to Europe until the last glaciation. This was accompanied by gradual replacement of "typically Siberian" gene variants with "typically European" ones. Morphological traits also changed as the species expanded, the changes in the body proportions being apparently adaptive. They are likely to reflect the transition of the cisco from the semi-anadromous life history type to the lacustrine type, which is more characteristic of the European form. Thus, the speciation of the vendace is clearly adaptive, at least with respect to some traits. It should be noted, however, that the results of this study raise doubt as to whether the vendace has entirely diverged from the Least Cisco, and the speciation has completed.