Gene flow,population growth and a novel substitution rate estimate in a subtidal rock specialist,the black‐faced blenny Tripterygion delaisi (Perciformes,Blennioidei, Tripterygiidae) from the Adriatic Sea

Population histories depend on the interplay between exogeneous and endogeneous factors. In marine species, phylogeographic and demographic patterns are often shaped by sea level fluctuations, water currents and dispersal ability. Using mitochondrial control region sequences (n = 120), we infer phylogeographic structure and historic population size changes of a common littoral fish species, the black‐faced blenny Tripterygion delaisi (Perciformes, Blennioidei, Tripterygiidae) from the north‐eastern Adriatic Sea. We find that Adriatic T. delaisi are differentiated from conspecific populations in the remaining Mediterranean, but display little phylogeographic structure within the Adriatic basin. The pattern is consistent with passive dispersal of planktonic larvae along cyclonic currents within the Adriatic Sea, but limited active dispersal of adults. Demographic reconstructions are consistent with recent population expansion, probably triggered by rising sea levels after the last glacial maximum (LGM). Placing the onset of population growth between the LGM and the warming of surface waters (18 000–13 000 years BP) and employing a novel expansion dating approach, we inferred a substitution rate of 2.61–3.61% per site per MY. Our study is one of only few existing investigations of the genetic structure of animals within the Adriatic basin and is the first to provide an estimate for mitochondrial control region substitution rates in blennioid fishes.     

Characterization of microsatellite loci in village indigobirds Vidua chalybeata and cross‐species amplification in estrildid and ploceid finches

We characterized 11 microsatellite primer pairs for the village indigobird Vidua chalybeata. The loci were highly polymorphic, with 7–13 alleles per locus. Gene diversity, estimated as expected heterozygosity, ranged from 0.52 to 0.86, and was generally matched by levels of observed heterozygosity (0.49–0.91). Many of these primer pairs amplified polymorphic loci in cross‐species amplification trials with a variety of estrildid and ploceid finches and a sparrow, Passer griseus. These primers will be valuable for genetic analyses of the brood parasitic indigobirds and whydahs (genus Vidua) as well as other Old World finches.     

Past lake shore dynamics explain present pattern of unidirectional introgression across a habitat barrier

Introgression patterns between divergent lineages are often characterized by asymmetry in the direction and among-marker variation in the extent of gene flow, and therefore inform on the mechanisms involved in differentiation and speciation. In the present study, we test the hypothesis that unidirectional introgression between two phenotypically and genetically distinct lineages of the littoral, rock-dwelling cichlid fish Tropheus moorii across a wide sandy bay is linked to observed differences in mate preferences between the two lineages. This hypothesis predicts bi-directional nuclear gene flow and was rejected by congruent patterns of introgression in mtDNA, AFLP and microsatellite markers, with admixture confined to the populations west of the bay. This pattern can be explained on the basis of habitat changes in the course of lake level fluctuations, which first facilitated the development of a symmetric admixture zone including the area corresponding to the present sand bay and then shaped asymmetry by causing local extinctions and cessation of gene flow when this area became once more inhabitable. This conforms with previous assumptions that habitat dynamics are a primary determinant of population-level evolution in Tropheus. In this respect, Tropheus may be representative of species whose preferred habitat is subject to frequent re-structuring.     

Variability of the Upper Palaeolithic skulls from Predmostí near Prerov (Czech Republic): craniometric comparison with recent human standards.

One of the largest skeletal series of the Upper Palaeolithic period from Predmostí was destroyed during the Second World War, but the study of this material continues up to the present. The discovery of Matiegka's original photographic documentation on glass plates [Velemínská et al., 2004. The use of recently re-discovered glass plate photo-documentation of those human fossil finds from Predmostí u Prerova destroyed during World War II. J. Nat. Mus. Nat. Hist. Ser. 173, 129-132] gives an opportunity to perform a new and detailed craniometric analysis of five adult skulls in their lateral projection. The craniometric data were analysed using specialised Craniometrics software, and the analysis included morphological and dimensional comparisons with current Central European norms. The aim of the study was not only to monitor the skull shape as a whole, but predominantly, to evaluate the size and shape of various parts of the splanchnocranium. The Upper Palaeolithic skulls are significantly longer, and male skulls are also higher than the current norms. The crania of anatomically modern humans are characterised by two general structural features: mid-lower facial retraction and neurocranial globularity. The height of the face of the Palaeolithic skulls corresponds to that of the current Central European population. The face has a markedly longer mandibular body (3-4 SD), while female mandibular rami are shorter. The skulls are further characterised by a smaller gonial angle, the increased steepness of the mandibular ramus, and the greater angle of the chin. These changes in the size and shape associated with anterior rotation of the face produce a strong protrusion of both jaws, but the sagittal inter-maxillary relationships remain unchanged. The observed facial morphology is similar to the Czech Upper Palaeolithic skulls from Dolní Vestonice. This study confirms the main diachronic changes between skulls of Upper Palaeolithic and present-day human populations.     

A single mitochondrial haplotype and nuclear genetic differentiation in sympatric colour morphs of a riverine cichlid fish

Some of the diversity of lacustrine cichlid fishes has been ascribed to sympatric divergence, whereas diversification in rivers is generally driven by vicariance and geographic isolation. In the riverine Pseudocrenilabrus philander species complex, several morphologically highly distinct populations are restricted to particular river systems, sinkholes and springs in southern Africa. One of these populations consists of a prevalent yellow morph in sympatry with a less frequent blue morph, and no individuals bear intermediate phenotypes. Genetic variation in microsatellites and AFLP markers was very low in both morphs and one single mtDNA haplotype was fixed in all samples, indicating a very young evolutionary age and small effective population size. Nevertheless, the nuclear markers detected low but significant differentiation between the two morphs. The data suggest recent and perhaps sympatric divergence in the riverine habitat.     

Age and spread of the haplochromine cichlid fishes in Africa

The Haplochromini are by far the most species-rich cichlid fish tribe that originated along with the so-called primary radiation of the Lake Tanganyika cichlid species flock, i.e. at the same time during which the majority of the endemic Lake Tanganyika cichlid tribes emerged. Unlike the other tribes, the haplochromines are not restricted to Lake Tanganyika but distributed throughout Africa, except for the northwestern part of the continent. Haplochromine cichlids seeded the adaptive radiation of cichlid fishes in Lakes Malawi, Kivu, Victoria, Turkana, as well as in the now extinct paleo-Lake Makgadikgadi. Here we present a comprehensive phylogenetic and phylogeographic analysis of haplochromine cichlids that is based upon DNA sequences of two mitochondrial gene segments of riverine taxa covering all major African biogeographic regions where haplochromines are found. Our analysis revealed that six lineages of haplochromines originated within a short period of time, about 5.3-4.4 MYA. These haplochromine lineages show a highly complex phylogeographic pattern, probably severely influenced by climate- and/or geology-induced changes of the environment, with river capture events most likely playing an important role for species dispersal.     

Variance in reproductive success and the opportunity for selection in a serially monogamous species: simulations of the mating system of <Emphasis Type="Italic">Tropheus</Emphasis> (Teleostei: Cichlidae)

Sexual selection is believed to play a major role in speciation processes of cichlid fishes in the East African Great Lakes, in particular Lakes Malawi and Victoria, by driving diversification in male nuptial coloration. In Lake Tanganyika, a high rate of color pattern diversification is found in the genus Tropheus, where more than 100, mostly allopatric, color morphs have been described. Whether color pattern differentiation in Tropheus could follow from sexual selection as well, has not yet been conclusively shown. Unlike typical sexually selected species, Tropheus are sexually monomorphic, establish temporary pair bonds and spawn monogamously. Variance in mating success among individuals would still allow for sexual selection, but due to their high population census sizes, parentage data from natural populations are difficult to obtain. Simulations designed according to existing data on mating behavior in Tropheus suggested that variance in male reproductive success can be substantial and lead to levels of opportunity for selection, which are similar to values estimated, for example, from natural populations of sexually dimorphic songbirds. Variance in male success was mostly affected by the way females perceived and reacted to differences between males, and to a lesser extent by the duration of components of the reproductive cycles of males and females. These results indicate that future work on the importance of sexual selection in Tropheus should concentrate on mate choice cues and female mate choice behavior, but does not depend critically on the acquisition of more detailed life history data.     

Male courtship preferences demonstrate discrimination against allopatric colour morphs in a cichlid fish

Whether premating isolation is achieved by male‐specific, female‐specific or sex‐independent assortative preferences often depends on the underlying evolutionary processes. Here we test mate preferences of males presented with females of different allopatric colour variants of the cichlid fish Tropheus sp., a Lake Tanganyika endemic with rich geographical colour pattern variation, in which the strength of sexual isolation varies between populations. We conducted two‐way mate choice experiments to compare behaviour of males of a red‐bodied morph (population Moliro) towards females from their own population with behaviour towards females from four allopatric populations at different stages of phylogenetic and phenotypic divergence. Males courted same‐population females significantly more intensely than females of other populations, and reduced their heteromorphic courtship efforts both with increasing genetic and increasing phenotypic distinctness of the females. In particular, females of a closely related red‐bodied population received significantly more courtship than either genetically distinct, similarly coloured females (‘Kirschfleck’ morph) or genetically related, differently coloured females (‘yellow‐blotch’ morph), both of which were courted similarly. Genetically and phenotypically distinct females (Tropheus polli) were not courted at all. Consistent with previous female‐choice experiments, female courtship activity also decreased with increasing genetic distance from the males’ population. Given successful experimental and natural introgression between colour morphs and the pervasive allopatry of related variants, we consider it unlikely that assortative preferences of both sexes were driven by direct selection during periods of secondary contact or, in turn, drove colour pattern differentiation in allopatry. Rather, we suggest that sexual isolation evolved as by‐product of allopatric divergence.     

Wasteful carotenoid coloration and its effects on territorial behavior in a cichlid fish

The famously diverse body coloration of cichlid fish serves communicative functions in mating and social interactions including competition for resources. Here, we examined the effects of a color pattern trait—the width of a yellow bar on a black body—on territorial competition in males and females of a color variant (“Ikola”) of the Lake Tanganyika cichlid Tropheus. First, measuring integumentary carotenoid concentrations in the yellow and black body regions, we established that wider yellow bars require more carotenoids allocated to body coloration. However, we also detected high carotenoid concentrations in the black body regions (>?100 µg/g fresh skin), raising questions about the function of non-displayed integumentary carotenoids. Behavioral experiments showed that fish with wider bars were quicker to explore an unfamiliar area of the tank. In experiments including presentations of fish dummies, the bar width of ‘territorial’ dummies had no effect on the latency time which test fish took to intrude into the dummies’ territories. However, male test fish performed fewer aggressive acts against wide-barred than against narrow-barred dummy competitors. Our results suggest that intimidation by wide bars as well as correlations between bar width and explorative behavior may contribute to mediating success in territorial Tropheus “Ikola”.