Genetic Diversity and Population History of the Endangered Killifish Aphanius baeticus

Abstract

The secondary freshwater fish fauna of the western-Iberian Peninsula basin is primarily restricted to local coastal streams, and man-made salt evaporation ponds, etc., which are susceptible to periodical flood and drought events. Despite its uniqueness in ecological adaptation to high saltwater tolerance, very little is known about this fauna's population dynamics and evolutionary history. The killifish, Aphanius baeticus (Cyprinodontidae) is an endemic species restricted to river basins on Spain's southern Atlantic coastline, considered as "Endangered." In this study, the genetic structure, diversity and historical demography of A. baeticus were analyzed using mitochondrial (cytochrome b, N = 131) and nuclear (4 out of 19 microsatellites tested, N = 288) markers across its distribution range. The phylogenetic and networking reconstruction revealed subtle phylogeographic structuring. A scattered expansion at the beginning of the interglacial periods, coupled with posterior events of extinction and colonization caused by periodical cycles of flooding, could explain the absence of well-defined phylogenetic relationships among populations. Moreover, very low genetic diversity values and a weak population differentiation were detected. We proposed that dispersals allowed by periodic floods connecting river drainages may have promoted a wide genetic exchange among populations and could have contributed to the current genetic relatedness of these populations.

Paleobiogeography of an Iberian endemic species,Luciobarbus sclateri(Günther, 1868) (Actinopterygii, Cyprinidae), inferred from mitochondrial and nuclear markers

“…Relationships similar to those observed between Guadalete and Guadalquivir populations have been reported in other freshwater fishes (Gonzalez, Pedraza‐Lara, & Doadrio, ). In the early Pleistocene, Guadalete was tributary of the Guadalquivir (Aguirre, ) and the present‐day configuration of the Guadalquivir and Guadalete basins involved several episodes of river captures (Rodriguez‐Vidal, Cáceres, & Rodriguez‐Ramirez, ).…”

“…Guadalquivir populations have been reported in other freshwater fishes (Gonzalez, Pedraza-Lara, & Doadrio, 2014). In the early Pleistocene, Guadalete was tributary of the Guadalquivir (Aguirre, 2004) and (Chester, 2012;Feio, 1952 These dynamic processes with secondary contacts in a complex geographic area are reflected in demographic changes that may promote differences in genetic diversity.…”

Diversity and structure of fragmented populations of a threatened endemic cyprinodontid (Aphanius sophiae) inferred from genetics and otolith morphology: Implications for conservation and management

“…Although more data are needed, our results suggest that the current distribution of A. sophiae in the Kor Basin is highly restricted into small populations and areas, largely isolated from each other and widely separated. The situation may be critical, and the genetic pattern exhibited by A. sophiae , particularly the high degree of population differentiation and low genetic diversity within populations is similar to those reported for endangered Aphanius species (González et al, , ). Aphanius sophiae is not listed on the Red List of endangered species by the International Union for Conservation of Nature (IUCN) because the limited data are available.…”

Population Genetic Structure and Genetic Diversity in Twisted-Jaw Fish,Belodontichthys truncatusKottelat & Ng, 1999 (Siluriformes: Siluridae), from Mekong Basin

“…Previous studies indicated that cyt b sequences can be successfully used to infer genetic structure and demographic history of freshwater fishes [6][7][8]. The information presented in this study will be useful for the management of B. truncatus.…”

“…For example, butter catfish, Ompok bimaculatus, in India (ℎ = 0.8270, = 0.00391) [19] and Trichomycterus areolatus from Chile [8]. However, the genetic diversity found in B. truncatus is higher than other catfish species from the Mekong River [20].…”