Mammal endemism In Italy: A review

Although there are various checklists of Italian mammals, there is not yet a synthesis of those mammals that are endemic to Italy. Therefore, we provide for the first time a detailed review on Italian mammal endemic species including endemic taxa deserving additional studies. This review is based on the most recent taxonomic revisions obtained using Scopus and Google Scholar databases. We also considered the age of endemic species. Some aspects of mammalian conservation are also provided and discussed

Hexavalents in spermatocytes of Robertsonian heterozygotes between Mus m. domesticus 2n 26 from the Vulcano and Lipari Islands (Aeolian Archipelago, Italy)

The size and shape of the chromosomes, as well as the chromosomal domains that compose them, are determinants in the distribution and interaction between the bivalents within the nucleus of spermatocytes in prophase I of meiosis. Thus the nuclear architecture characteristic of the karyotype of a species can be modified by chromosomal changes such as Robertsonian (RB) chromosomes. In this study we analysed the meiotic prophase nuclear organization of the heterozygous spermatocytes from Mus musculus domesticus 2n=26, and the synaptic configuration of the hexavalent formed by the dependent Rb chromosomes Rbs 6.16, 16.10, 10.15, 15.17 and the telocentric chromosomes 6 and 17. Spreads of 88 pachytene spermatocytes from two males were studied and in all of them five metacentric bivalents, four telocentric bivalents, one hexavalent and the XY bivalent were observed. About 48% of the hexavalents formed a chain or a ring of synapsed chromosomes, the latter closed by synapsis between the short arms of telocentric chromosomes 6 and 17. About 52% of hexavalents formed an open chain of 10 synapsed chromosomal arms belonging to 6 chromosomes. In about half of the unsynapsed hexavalents one of the telocentric chromosome short arms appears associated with the X chromosome single axis, which was otherwise normally paired with the Y chromosome. The cluster of pericentromeric heterochromatin mostly determines the hexavalent’s nuclear configuration, dragging the centromeric regions and all the chromosomes towards the nuclear envelope similar to an association of five telocentric bivalents. These reiterated encounters between these chromosomes restrict the interactions with other chromosomal domains and might favour eventual rearrangements within the metacentric, telocentric or hexavalent chromosome subsets. The unsynapsed short arms of telocentric chromosomes frequently bound to the single axis of the X chromosome could further complicate the already complex segregation of hexavalent chromosomes

Spotlight on islands.On the origin and diversification of an ancient lineage of the Italian wall lizard Podarcis siculus in the western Pontine Islands

Groups of proximate continental islands may conceal more tangled phylogeographic patterns than oceanic archipelagos as a consequence of repeated sea level changes, which allow populations to experience gene flow during periods of low sea level stands and isolation by vicariant mechanisms during periods of high sea level stands. Here, we describe for the first time an ancient and diverging lineage of the Italian wall lizard Podarcis siculus from the western Pontine Islands. We used nuclear and mitochondrial DNA sequences of 156 individuals with the aim of unraveling their phylogenetic position, while microsatellite loci were used to test several a priori insular biogeographic models of migration with empirical data. Our results suggest that the western Pontine populations colonized the islands early during their Pliocene volcanic formation, while populations from the eastern Pontine Islands seem to have been introduced recently. The inter-island genetic makeup indicates an important role of historical migration, probably due to glacial land bridges connecting islands followed by a recent vicariant mechanism of isolation. Moreover, the most supported migration model predicted higher gene flow among islands which are geographically arranged in parallel. Considering the threatened status of small insular endemic populations, we suggest this new evolutionarily independent unit be given priority in conservation efforts

Does divergence from normal patterns of integration increase as chromosomal fusions increase in number? A test on a house mouse hybrid zone

Chromosomal evolution is widely considered an important driver of speciation because it can promote the establishment of reproductive barriers. Karyotypic reorganization is also expected to affect the mean phenotype, as well as its development and patterns of phenotypic integration, through processes such as variation in genetic linkage between QTL regions or between regulatory regions and their targets. Here we explore the relationship between chromosomal evolution and phenotypic integration by analysing a well-known house mouse parapatric contact zone between a highly derived Robertsonian race (2n = 22) and populations with standard karyotype (2n = 40). Populations with hybrid karyotypes are scattered throughout the hybrid zone connecting the two parental races. Using mandible shape data and geometric morphometrics, we test the hypothesis that patterns of integration progressively diverge from the “normal” integration pattern observed in the standard race as they accumulate Robertsonian fusions. We find that the main pattern of integration observed between the posterior and anterior part of the mandible can be largely attributed to allometry. We find no support for a gradual increase in divergence from normal patterns of integration as fusions accumulate. Surprisingly, however, we find that the derived Robertsonian race (2n = 22) has a distinct allometric trajectory compared to the standard race. Our results suggest that either individual fusions disproportionately affect patterns of integration or that there are mechanisms which “purge” extreme variants in hybrids (e.g., reduced fitness of hybrid shape).publishe

Evolutionary and demographic correlates of Pleistocene coastline changes in the Sicilian wall lizard Podarcis wagleriana

Aim Emergence of coastal lowlands during Pleistocene ice ages might have provided conditions for glacial expansions (demographic and spatial), rather than contraction, of coastal populations of temperate species. Here, we tested these predictions in the insular endemic Sicilian wall lizard Podarcis wagleriana. Location Sicily and neighbouring islands. Methods We sampled 179 individuals from 45 localities across the whole range of P. wagleriana. We investigated demographic and spatial variations through time using Bayesian coalescent models (Bayesian phylogeographic reconstruction, Extended Bayesian Skyline plots, Isolation‐with‐migration models) based on multilocus DNA sequence data. We used species distribution modelling to reconstruct present and past habitat suitability. Results We found two main lineages distributed in the east and west portions of the current species range and a third lineage restricted to a small area in the north of Sicily. Multiple lines of evidence from palaeogeographic (shorelines), palaeoclimatic (species distribution models), and multilocus genetic data (demographic and spatial Bayesian reconstructions) indicate that these lineages originated in distinct refugia, located in the north‐western and south‐eastern coastal lowlands, during Middle Pleistocene interglacial phases, and came into secondary contact following demographic and spatial expansions during the last glacial phase. Main conclusions This scenario of interglacial contraction and glacial expansion is in sharp contrast with patterns commonly observed in temperate species on the continent but parallels recent findings on other Mediterranean island endemics. Such a reverse expansion–contraction (EC) dynamic has been likely associated with glacial increases of climatically suitable coastal lowlands, suggesting this might be a general pattern in Mediterranean island species and also in other coastal regions strongly affected by glacial marine regressions during glacial episodes. This study provides explicit predictions and some methodological recommendations for testing the reverse EC model in other region and taxa

The phylogenetic position of Lygodactylus angularis and the utility of using the 16S rDNA gene for delimiting species in Lygodactylus (Squamata, Gekkonidae)

The African genus Lygodactylus Gray, is composed of roughly 60 species of diurnal geckos that inhabit tropical and temperate Africa, Madagascar, and South America. In this study, we assessed the phylogenetic position of L. angularis, for which molecular data were so far lacking, by means of sequence analysis of the mitochondrial 16S rDNA gene. We also compared intraspecific vs. interspecific genetic divergences using an extended data set (34 species, 153 sequences), to determine whether a fragment of this gene can be useful for species identification and to reveal the possible existence of new cryptic species in the genus. The analysis placed L. angularis in a monophyletic group together with members of “fischeri” and “picturatus” groups. Nevertheless, the independence of the “angularis” lineage is supported by the high genetic divergence. Comparison of intraspecific vs. interspecific genetic distances highlights that, assuming an equal molecular rate of evolution among the studied species for the used gene, the threshold value useful for recognising a candidate new species can be tentatively placed at 7%. We identified four species that showed an intraspecific divergence higher than, or close to, the 7% threshold: L. capensis (8.7%), L. gutturalis (9.3%), L. madagascariensis (6.5%) and L. picturatus (8.1%). Moreover, two species, L. mombasicus and L. verticillatus, are paraphyletic in terms of gene genealogy. Thus, the study shows that a short fragment of the 16S rDNA gene can be an informative tool for species-level taxonomy in the genus Lygodactylus

Who are you? The genetic identity of some insular populations of Hierophis viridiflavus s.l. from the Tyrrhenian Sea

This work investigates the genetic identity of Hierophis viridiflavus s.l. specimens from insular populations, to determine which of the two previously identified species is present on each island. Here, the authors hypothesise about times and modes of colonization and discuss the faunistic value of the obtained results. This follows the recent proposal to consider the two clades as two different species. Specimens from the islands of Favignana, Lipari and Vulcano belong to H. carbonarius and probably all belong to putative Sicilian source populations. Conversely, all individuals from the Pontine Islands (Ponza, Palmarola, Ventotene) should be considered to belong to H. viridiflavus. Even if genetically identical to the specimens from the Tyrrhenian Italian coast, these individuals show a darker colouration, very similar to the one usually shown by H. carbonarius specimens. Considering that the Pontine H. viridiflavus populations probably have a very recent origin, the dark livery of these individuals could be the result of a rapid morphological adaptation to insular environments

Who are you? The genetic identity of some insular populations of <em>Hierophis viridiflavus</em> s.l. from the Tyrrhenian Sea

This work investigates the genetic identity of Hierophis viridiflavus s.l. specimens from insular populations, to determine which of the two previously identified species is present on each island. Here, the authors hypothesise about times and modes of colonization and discuss the faunistic value of the obtained results. This follows the recent proposal to consider the two clades as two different species. Specimens from the islands of Favignana, Lipari and Vulcano belong to H. carbonarius and probably all belong to putative Sicilian source populations. Conversely, all individuals from the Pontine Islands (Ponza, Palmarola, Ventotene) should be considered to belong to H. viridiflavus. Even if genetically identical to the specimens from the Tyrrhenian Italian coast, these individuals show a darker colouration, very similar to the one usually shown by H. carbonarius specimens. Considering that the Pontine H. viridiflavus populations probably have a very recent origin, the dark livery of these individuals could be the result of a rapid morphological adaptation to insular environments

The intriguing biogeographic pattern of the Italian wall lizard Podarcis siculus (Squamata: Lacertidae) in the Tuscan Archipelago reveals the existence of a new ancient insular clade

The Tuscan Archipelago is one of the most ancient and ecologically heterogeneous island systems in the Mediterranean. The biodiversity of these islands was strongly shaped by the Pliocene and Pleistocene sea regressions and transgression, resulting in different waves of colonization and isolation of species coming from the mainland. The Italian wall lizard, Podarcis siculus, is present on the following islands of the Tuscan Archipelago: Elba, Giglio, Giannutri, Capraia, Montecristo and Cerboli. The species in the area displays a relatively high morphological variability that in the past led to the description of several subspecies. In this study, both the genetic and morphological diversity of P. siculus of the Tuscan Archipelago were investigated. Specifically, the meristic characters and the dorsal pattern were analyzed, while the genetic relationships among these populations were explored with mtDNA and microsatellite nuclear markers to reconstruct the colonization history of the Archipelago. Our results converge in the identification of at least two different waves of colonization in the Archipelago: Elba, and the populations of Cerboli and Montecristo probably originate from historical introductions from mainland Tuscany, while those of Giglio and Capraia are surviving populations of an ancient lineage which colonized the Tuscan Archipelago during the Pliocene and which shares a common ancestry with the P. siculus populations of south-eastern Italy. Giannutri perhaps represents an interesting case of hybridization between the populations from mainland Tuscany and the Giglio-Capraia clade. Based on the high phenotypic and molecular distinctiveness of this ancient clade, these populations should be treated as distinct units deserving conservation and management efforts as well as further investigation to assess their taxonomic status

Chromosomal and molecular characterization of Aethomys

Aethomys is a common and widespread rodent genus in the African savannas and grasslands. However, its systematics and taxonomy are still unclear as no study has covered the entire range. In fact it might not be a monophyletic genus and perhaps should be split into two subgenera, Micaelamys and Aethomys. In this paper, we present findings based on the cytogenetics and the entire cytochrome b sequence of two species from Zambia (A. kaiseri) and Tanzania (A. chrysophilus), and we compare them with the sequences of a South African species (A. namaquensis) and other allied muroid genera. Comparison of the banded chromosomes revealed complete G-band homology between the autosomes of the two species. However, the X and Y chromosomes clearly differ in size and in C- and G-banding, being much larger in A. kaiseri. Comparison of the cytochrome b sequences places the separation between A. kaiseri and A. chrysophilus at 4.49 Mya, a period of intense speciation in other African muroids. The resulting phylogeny strongly supports the idea of a paraphyletic group, suggesting the need to elevate the previously described subgenera to the genus rank