Isolation by distance, gene flow and phylogeography in the Proasellus coxalis-group (Crustacea, Isopoda) in Central Italy: Allozyme data

Fifteen populations belonging to the Proasellus coxalis-group were surveyed for genetic variation at 19 enzymatic loci in order to clarify the degree of genetic structuring of this species at the scale of Central Italy. With Neighbour-Joining analysis, it was possible to identify two main clusters, the first grouping populations sampled in coastal areas of Central Italy, the second comprising several populations from inland areas of the Apennines. In the first group, genetic relationships follow a geographic scheme, with populations arranged according to the proximity of the collecting sites. The inland populations have less clear geographic relationships and a higher degree of genetic differentiation. In view of the paleogeography of the study areas, I hypothesise a more recent penetration of this taxon into the Central Italian alluvial coastal plains (subjected to cyclical marine ingressions during the Quaternary) from sources of colonisation in the inland areas. The higher genetic differentiation of the inland populations presumably reflects a longer evolutionary history and could be explained by the periodic fragmentation of river catchments during Pleistocene climatic fluctuations. Such an evolutionary scenario is supported by F-statistics analyses. Effective dispersal of individuals between populations can be hypothesised for the coastal populations but not for the inland ones. On the whole, there is a pattern of isolation by distance, but a large amount of gene flow seems to reflect historical rather than ongoing gene exchange

Will the Italian endemic gudgeon, Gobio benacensis, survive the interaction with the invasive introduced Gobio gobio?

The genus Gobio in Italy was represented by the endemic species G. benacensis. The original distribution of this species was the Padano-Venetian district, but since a long time it was introduced in central Italy. Introductions of alien species to Italy during the last 10 years brought the sudden introduction of the Danubian G. gobio. Genetic and morphological analyses revealed the extensive presence of G. gobio, which rapidly colonised several rivers in Italy causing the progressive decline of G. benacensis, which now should be considered as an endangered species. Among examined populations those found in the Tagliamento River and transplanted in the Ombrone River represent genetic reservoirs of this species which will probably disappear in northern Italy

Isolation and characterization of five microsatellite loci in Dolichopoda cave crickets (Orthoptera Rhaphidophoridae)

Five microsatellite loci are described for the cave cricket genus Dolichopoda. Preliminary data on allelic variation of these loci are presented for one population of D. schiavazzii and one population of D. laetitiae to test their usefulness in fine-scale studies of the genetic aspect of cave colonization. Cross-species amplifications were carried out in four other Dolichopoda species and in two species belonging to another cave cricket genus (Troglo-philus) to test the potential use of these microsatellite markers in studies of both congeneric species and species belonging to the same family

Occurrence of the scalloped ribbonfish Zu cristatus(Lampridiformes) in coastal waters of the central Tyrrhenian Sea, Italy

The occurrence of two individuals of Zu cristatus at 2 m depth in coastal waters of the Gulf of Castellamare (Tyrrhenian Sea, Italy) together with records of this rare pan-Oceanic mesopelagic species is reported. Analyses of two mitochondrial genes (12 s and 16 s; 936 bp) revealed a 2.6% sequence divergence between Mediterranean and Pacific (Japanese) samples of the species

Molecular systematics, phylogeny and biogeography of roaches (Rutilus, Teleostei, Cyprinidae)

The aims of the present study are: (1) to produce a phylogenetic hypothesis for the genus Rutilus by using sequence variation of the entire mitochondrial (mt) cytochrome b (cyt-b) gene. To accomplish this we had sampled a total of 22 populations from the Eastern peri-Mediterranean area and Central Europe. These include 12 species (five of which with multiple populations; Fig. 1 and Table 1) out of the 14 reported in FishBase; (2) to test whether molecular data support the current systematics of the genus; and (3) to produce a biogeographic hypothesis for its diversification based on estimates of divergence times. Results will be discussed in light of the two contrasting biogeographic scenarios available for Southern European primary freshwater fishes

Origin and evolutionary relationships of giant Galapagos tortoises

Perhaps the most enduring debate in reptile systematics has involved the giant Galapagos tortoises (Geochelone nigra), whose origins and systematic relationships captivated Charles Darwin and remain unresolved to this day. Here we report a phylogenetic reconstruction based on mitochondrial DNA sequences from Galapagos tortoises and Geochelone from mainland South America and Africa. The closest living relative to the Galapagos tortoise is not among the larger-bodied tortoises of South America but is the relatively small-bodied Geochelone chilensis, or Chaco tortoise. The split between G. chilensis and the Galapagos lineage probably occurred 6 to 12 million years ago, before the origin of the oldest extant Galapagos island. Our data suggest that the four named southern subspecies on the largest island, Isabela, are not distinct genetic units, whereas a genetically distinct northernmost Isabela subspecies is probably the result of a separate colonization. Most unexpectedly, the lone survivor of the abingdoni subspecies from Pinta Island ("Lonesome George") is very closely related to tortoises from San Cristobal and Espanola, the islands farthest from the island of Pinta, To rule out a possible recent transplant of Lonesome George, we sequenced DNA from three tortoises collected on Pinta in 1906, They have sequences identical to Lonesome George, consistent with his being the last survivor of his subspecies. This finding may provide guidance in finding a mate for Lonesome George, who so far has failed to reproduce

Genetic divergence in the cave cricket Troglophilus neglectus (Orthoptera Rhaphidophoridae): mitochondrial and nuclear DNA data.

In this study we used sequence polymorphisms at one mitochondrial and one nuclear gene (Cytochrome Oxidase subunit I and Internal Transcribed Spacer 1, respectively) to assess the degree of genetic divergence among 21 populations of the cave cricket Troglophilus neglectus (Orthoptera, Rhaphidophoridae), a species whose currently known range extends from the Balkan Peninsula to Southern Bavaria. Nineteen populations were sampled in Northern Italy, Slovenia, Croatia and Bosnia and Herzegovina, while two populations came from Germany (Lower Saxony) and Czech Republic, thus well outside the species range. Molecular data revealed a high level of fragmentation, with most of the study populations bearing exclusive haplotypes, the sole exception being the German and Czech specimens, which carried haplotypes also occurring at Slovenian locations. Spatial distribution of genetic heterogeneity and pattern of genetic divergence argue in favor of a recent origin of the two Central European populations, possibly through man-mediated dispersal event(s). These populations being not considered, our data are in remarkable agreement with a previous study based on allozymes conducted on a subset of populations of the same species and, more generally, with what is known on the population genetics of peri-Mediterranean Rhaphidophorids

Foreword to the special issue "new frontiers for monitoring European biodiversity: The role and importance of amphipod crustaceans"

[No abstract available

Variation of genetic and behavioural traits in the sandhopper Talitrus saltator (Crustacea Amphipoda) along a dynamic sand beach

In an attempt to unravel the possible relationships among coastal stability, genetic variability and orientation behaviour in the sandhopper Talitrus saltator, we have screened four subpopulations of this species. Sandhoppers along 3 km of a dynamic sand beach were studied for orientation performance (i.e. adherence to the seaward theoretical escape direction (TED)) and sequence variation for a fragment of the mitochondrial (mt) gene encoding for the cytochrome oxidase Subunit I (COI). The sampling sites differed in the stability of the shoreline (from severely eroded to accreting). Analysis of molecular variance (AMOVA) revealed significant subdivisions among the four locations. The subpopulation sampled at the most eroded point showed no haplotype diversity and had the highest scatter in orientation. Genetic diversity increased with decreasing erosion. Orientation performances were best where the beach is in dynamic equilibrium, and were progressively more scattered at the accreting points. Multiple linear regression analyses demonstrated that the variables and factors that affected orientation significantly were daytime, global solar radiation, sex of individuals and haplotype diversity. Environmental factors are likely to influence sandhopper behaviour on a short and medium time scale (i.e. from single individual life span to a few generations). The data also suggest that temporal stability of the shoreline has a positive effect on the genetic variability of the resident sandhopper populations