Department of Theoretical and Applied Sciences

The Lesser Flamingo Phoeniconaias minor is a nomadic species, which inhabits shallow alkaline lakes and pans in sub-Saharan Africa and southern Asia. The extent of genetic diversity and the degree of differentiation within and among populations are important factors to determine in order to help manage and conserve the species, categorised as Near Threatened by the IUCN. This study provides an assessment of the population structure of the two largest African populations of P. minor by genotyping six microsatellite loci from 30 individuals sampled on Lake Bogoria (Kenya) and 11 individuals from Makgadikgadi Sua Pan (Botswana). The alleles detected per locus ranged from four to 13. The Lake Bogoria population harboured 15 specific alleles, whereas the Makgadikgadi Sua Pan population only six alleles. Moderate genetic diversity (He = 0.64–0.69) was comparable with populations that have not suffered from demographic bottlenecks or inbreeding. The populations are genetically similar with little differentiation (FST and RST not significantly different from zero). Small but continuous gene flow (the estimated average number of individuals exchanged is 3–4 per generation) was found, probably reflecting the bird's nomadic behaviour and the natural presence of temporary shallow waters between the two sampled populations. The results suggest that inbreeding effects at present are unlikely, and hence that the loss and/or degradation of its specialised habitat remains the primary concern for the species’ continued survival.

Previous studies have given substantial attention to external factors that affect the distribution and diversification of freshwater fish in Europe and North America, in particular Pleistocene and Holocene glacial cycles. In the present paper we examine sequence variation at one mitochondrial and four nuclear loci (over 3kbp) from populations sampled across several drainages of all species of Barbus known to inhabit Italian freshwaters (introduced B. barbus and native B. balcanicus, B. caninus, B. plebejus and B. tyberinus). By comparing species with distinct ecological preferences (rheophilic and fluvio-lacustrine) and using a fossil-calibrated phylogeny we gained considerable insight about the intrinsic and extrinsic processes shaping barbel distribution, population structure and speciation. We found that timescales of Italian barbel diversification are older than previously thought, starting in the Early Miocene, and involving local and regional tectonism and basin paleo-evolutio...

A study was conducted on the habitat distribution of four sympatric species of Periophthalmus (the silver-lined mudskipper Periophthalmus argentilineatus, the slender mudskipper Periophthalmus gracilis, the kalolo mudskipper Periophthalmus kalolo and the Malacca mudskipper Periophthalmus malaccensis) from northern Sulawesi. Molecular phylogenetic reconstructions based on one mtDNA marker (16S) were used to validate the morphological taxa, identifying five molecular clades. Periophthalmus argentilineatus includes two molecular species, which are named Periophthalmus argentilineatus clades F and K. Multivariate direct gradient analysis show that these species form
three distinct ecological guilds, with the two molecular species occurring in different guilds. Periophthalmus clade F is ecologically eurytypic; Periophthalmus clade K and P. kalolo are prevalent in ecosystems isolated by strong oceanic currents and at shorter distances from the sea; P. gracilis plus P. malaccensis are prevalent in ecosystems connected by shallow coastal waters, in vegetated habitats at larger distances from the sea. This indicates for the first time that mudskipper species exhibit a range of adaptations to semiterrestrialism not only within genera, but even within morphospecies, delineating a much more complex adaptive scenario than previously assumed.

ABSTRACT Alcolapia is a minor genus of small-bodied, polymorphic cichlids inhabiting the lagoons and hot springs surrounding the soda lakes Natron (largely in Tanzania) and Magadi (Kenya). Three Alcolapia species are present at Natron (Alcolapia alcalicus, Alcolapia ndalalani and Alcolapia latilabris) and one at Magadi (Alcolapia grahami). All are IUCN Red Listed as either vulnerable or endangered. We performed analyses of morphometric and genetic structure on 13 populations of the Natron Alcolapia flock, and one A. grahami population of Lake Magadi as an out-group. Morphometric analyses revealed significant differentiation in the head and mouth shape of the species at Natron. From a genetic perspective, among 70 mtDNA control region sequences 17 haplotypes were found, showing in the minimum spanning network a star-like pattern around the widespread haplotype 2lat. At Natron, there was limited genetic differentiation between the different populations of A. alcalicus and A. latilabris, despite apparent ecological barriers of extreme alkalinity that suggested their populations were isolated. Instead, there appeared to be some population connectivity, with a rate of 0.5–2.3 migrants per generation suggesting that natural factors, such as intense rains or transmission by large piscivorous birds, facilitate population connectivity and maintain genetic similarity. The outputs of high population connectivity and one genetic unit at the basin level (despite morphological divergence) suggest that any human activities that disrupt the connectivity of the freshwater resources of the Natron catchment could further threaten the integrity and current status of these already threatened fish populations.