F. Güler Ekmekçi

Divergence with gene flow between Ponto‐Caspian refugia in an anadromous cyprinid Rutilus frisii revealed by multiple gene phylogeography

The Black and Caspian Seas have experienced alternating periods of isolation and interconnection over many Milankovitch climate oscillations and most recently became separated when the meltwater overflow from the Caspian Sea ceased at the end of the last glaciation. Climate‐induced habitat changes have indisputably had profound impacts on distribution and demography of aquatic species, yet uncertainties remain about the relative roles of isolation and dispersal in the response of species shared between the Black and Caspian Sea basins. We examined these issues using phylogeographical analysis of an anadromous cyprinid fish Rutilus frisii. Bayesian coalescence analyses of sequence variation at two nuclear and one mitochondrial genes suggest that the Black and Caspian Seas supported separate populations of R. frisii during the last glaciation. Parameter estimates from the fitted isolation‐with‐migration model showed that their separation was not complete, however, and that the two populations continued to exchange genes in both directions. These analyses also suggested that majority of migrations occurred during the Pleistocene, showing that the variation shared between the Black and Caspian Seas is the result of ancient dispersal along the temporary natural connections between the basins, rather than of incomplete lineage sorting or recent human‐mediated dispersal. Gene flow between the refugial populations was therefore an important source of genetic variation, and we suggest that it facilitated the evolutionary response of the populations to changing climate.

Natural thermal adaptation increases heat shock protein levels and decreases oxidative stress

Heat shock proteins (HSPs), originally identified as heat-inducible gene products, are a family of highly conserved proteins that respond to a wide variety of stress including oxidative stress. Although both acute and chronic oxidative stress have been well demonstrated to induce HSP responses, little evidence is available whether increased HSP levels provide enhanced protection against oxidative stress under elevated yet sublethal temperatures. We studied relationships between oxidative stress and HSPs in a physiological model by using Garra rufa (doctor fish), a fish species naturally acclimatized to different thermal conditions. We compared fish naturally living in a hot spring with relatively high water temperature (34.4±0.6 °C) to those living in normal river water temperature (25.4±4.7 °C), and found that levels of all the studied HSPs (HSP70, HSP60, HSP90, HSC70 and GRP75) were higher in fish living in elevated water temperature compared with normal river water temperature. In contrast, indicators of oxidative stress, including protein carbonyls and lipid hydroperoxides, were decreased in fish living in the elevated temperature, indicating that HSP levels are inversely associated with oxidative stress. The present results provide evidence that physiologically increased HSP levels provide protection against oxidative stress and enhance cytoprotection.

Alburnoides manyasensis (Actinopterygii, Cyprinidae), a new species of cyprinid fish from Manyas Lake basin, Turkey

Abstract Alburnoides manyasensis, sp. n., is described from the Koca Stream (Lake Manyas drainage, Marmara Sea basin) in Anatolia. It is distinguished from all species of Alburnoides in Turkey and adjacent regions, Alburnoides tzanevi (Rezovska [Rezve], Istranca and Terkos streams in the western Black Sea drainage), Alburnoides cf. smyrnae (Banaz Stream, a drainage of Büyük Menderes River, Aegean Sea basin), Alburnoides fasciatus (streams and rivers in the eastern Black Sea drainage) and Alburnoides eichwaldii (Kura and Aras rivers [a drainage of Kura River], Caspian Sea basin) by a combination of the following characters (none unique to the species):marked hump at nape, especially in specimens larger than 60 mm SL; partly developed ventral keel between pelvic fin and anal fin, scaleless 1/2 to 2/3 its length; body depth at dorsal-fin origin 29−32% SL; caudal peduncle depth 11−12% SL; 45–52+ 2–3 lateral-line scales; 9–12 scale rows between lateral line and dorsal-fin origin; 4–5 scale rows between lateral line and anal-fin origin, 10½–12½ branched anal-fin rays; 40–42 total vertebrae.

Three new species of Alburnoides (Teleostei: Cyprinidae) from Euphrates River, Eastern Anatolia, Turkey

Three new species of Alburnoides, Alburnoides emineae sp. n., Alburnoides velioglui sp. n., Alburnoides recepi sp. n., are described from the Euphrates River drainages (Persian Gulf basin) in eastern Anatolia, Turkey. Alburnoides emineae, from Beyazsu Stream (south-eastern Euphrates River drainage), is distinguished from all species of Alburnoides in Turkey and adjacent regions by a combination of the following characters (none unique to the species): a well developed ventral keel between pelvic and anal fins, commonly scaleless or very rarely 1-2 scales covering the anterior portion of the keel; a deep body (depth at dorsal-fin origin 31-36% SL); 37-43 + 1-2 lateral-line scales, 13½-15½ branched anal-fin rays; number of total vertebrae 41-42, modally 41, comprising 20-21 abdominal and 20-21 caudal vertebrae. Alburnoides velioglui, from Sırlı, Karasu, Divriği and Sultansuyu streams (northern and northeastern Euphrates River drainages), is distinguished by a poorly developed ventral keel, completely scaled; a moderately deep body (depth at dorsal-fin origin 24-29% SL); 45-53 + 1-2 lateral-line scales, 11½ -13½ branched anal-fin rays; number of total vertebrae 41-42, modally 42, comprising 20-22 abdominal and 20-21 caudal vertebrae. Alburnoides recepi, from Merzimen Stream (southern Euphrates River drainage), is distinguished by a well developed ventral keel, completely scaleless; a deep body (depth at dorsal-fin origin 29-34% SL); 47-56 + 2-3 lateral-line scales; 13½-16½ branched anal-fin rays; number of total vertebrae 38-40, comprising 19-21 abdominal and 18-20 caudal vertebrae.

Three new species of Alburnoides from the southern Black Sea basin (Teleostei: Cyprinidae)

Three new Alburnoides species are described from the southern Black Sea basin. Alburnoides kurui, new species, from the Yeşilırmak drainage, is distinguished from other species of Alburnoides in the southern Black Sea basin, the Marmara basin and the Anatolian Aegean basin by having a scaleless keel between the posterior pelvic fin base and the anus or with rarely 1 scale covering the anterior part of the keel; 50-59 total lateral-line scales; 13½-15½ branched anal-fin rays and 7-9 gill rakers. Alburnoides freyhofi, new species, from the Kızılırmak drainage, is distinguished by having a scaleless keel between the posterior pelvic fin base and the anus, 44-53 total lateral-line scales; 14½-16½ branched anal-fin rays and 5-7 gill rakers. Alburnoides kosswigi, new species, from the Sakarya drainage, is distinguished by having a scaleless keel between the posterior pelvic fin base and the anus or rarely with 1-3 scales covering the anterior part of the keel; 43-57 total lateral-line scales; 11½-13 (14)½ branched anal-fin rays and 5-7 gill rakers.