Marco A. L. Zuffi and Augusto Gentilli
Gaetano Odierna, Augusto Gentilli, Marco Zuffi and Gennaro Aprea
In the current paper we show the results obtained using standard and banding staining methods (Ag-NOR-, CMA3-, C-banding and sequential colorations (or Alu I digestions) + CMA3 + DAPI) in specimens of Cerastes vipera, Vipera aspis, V. atra, and V. hugyi. Cerastes vipera presented chromosomal characters, primitive in snakes, as a karyotype of 2n = 36 chromosomes, with 16 biarmed macrochromosomes and 20 microchromosomes, NORs on one microchromosome pair and absence of cytologically evident sex chromosomes, at least with the methods used. The three taxa of Vipera studied showed chromosomal characters either derived, or primitive or at an initial stage of differentiation. All three species showed a karyotype (derived) of 2n = 42 chromosomes with 22 macro- and 20 micro-chromosomes; they all showed NORs on one micro-chromosome pair and presented Z and W chromosomes at an initial stage of differentiation. Sexchromosomes Z and W, were in fact homomorphic, but the former was near all euchromatic, while the W chromosome was almost completely heterochromatic. All the three taxa of Vipera resulted, however, karyologically diversified, mainly due to the number of macro-chromosomes pairs with a centromeric, CMA3 positive heterochromatin: almost all the pairs in V. aspis, two pairs in V. atra and absent in V. hugyi.
Augusto Gentilli, Roberto Sacchi, Marco Mangiacotti and Stefano Scali
Interspecific competition in contact areas is a major topic in ecological studies. A number of studies were carried out on European vipers, focusing on contact areas between two or three species characterized as appropriate by ecological needs more or less similar. The aim of this study is to extend the analysis of this topic to the case of Vipera aspis and V. berus in an alpine area of northern Italy, by comparing suitability models to verify which ecological factors affect their occurrence and to assess a possible niche separation. Potential distribution was modelled using the maximum entropy method, using six non-correlated ecogeographical variables as predictors. The models fitted well for both species (mean AUC = 0.926; 87.4% of testing data correctly classified). The most informative variables were: habitat, altitude and solar radiation for the asp viper; altitude and habitat for the adder. Deciduous woods, meadows and urban areas had a positive effect on V. aspis distribution as wetlands, meadows and rocks vegetation did on V. berus. However, the variable best separating the species was the elevation, the adder occurring more frequently at higher altitude than the asp viper. Our data showed that the two vipers were mutually exclusive, as already observed by Saint Girons in 1975. Vipera aspis is more thermophilic and lives at low altitude, while Vipera berus lives under cool and humid areas typical of alpine pastures. A similar pattern were found in the contact areas between European vipers belonging to the V. aspis and Pelias group respectively.
Stefano Scali, Diego Rubolini, Mauro Fasola, Edoardo Razzetti, Roberto Sacchi, Fabio Pupin, Paolo Galeotti and Augusto Gentilli
Permanent colour polymorphism in lizards is maintained by complex interactions between environmental pressures and physiological traits (such as immune responsiveness) that differ among morphs. In this study we investigated whether T-cell mediated immune response vary among male colour morphs in the trimorphic (white, yellow and red) common wall lizard, Podarcis muralis. We found that yellow males showed a lower immune response compared to both red and white males, whose responses were similar. Thus, immune responsiveness is morph-specific in male common wall lizards, suggesting that this physiological trait could play an important role in maintaining colour polymorphism in this species. Moreover, immune responsiveness significantly increased with increasing male size, irrespective of colour morph, indicating that it could be regarded as a condition-dependent trait.
Stefano Scali, Catarina Rato, Miguel Carretero, Augusto Gentilli, Marco Zuffi, Edoardo Razzetti, Sara Fornasiero, Harris and Claudia Corti
The phylogeography of the colubrid snake Hierophis viridiflavus was estimated using ND4 mtDNA sequences and a fragment of the nuclear marker β-fibrinogen intron 7. This species has a wide distribution across the Mediterranean region, and is characterized by three distinct colour patterns (“viridiflavus”, abundistic, and melanic-melanotic) with a quite well defined geographic distribution. The “viridiflavus” pattern occurs in the northwestern and central areas of the species' range, the abundistic pattern is typical of the individuals from Corsica and Sardinia, and the melanic-melanotic coloration is present in northeastern and southern Italy, and Sicily. A total of 42 individuals from most of the species' range (including Pyrenees, central France, Italian Peninsula, Corsica, Sardinia and Sicily) were analyzed. Results support the existence of two different mtDNA lineages, one from Spain, France, Corsica, Sardinia, and continental Italy mainly west of the Apennines, and another one occurring in the southern part of Italy and northeast of the Apennines, with a 4% genetic divergence between them. Since both mtDNA lineages are found in northwestern Italy, where the “viridiflavus” colour pattern is almost exclusively found, it is clear that colour pattern is not linked to the mtDNA clades. The same is evident for β-fibrinogen, which is not subdivided geographically in the way that the mtDNA lineages are. Regarding Corsica and Sardinia, the limited genetic differentiation of island populations from the western continental lineage, indicates that these populations are a result of a recent colonization in accordance with recent described phylogeographic patterns.
Mauro Fasola, Daniele Pellitteri-Rosa, Fabio Pupin, Stefano Scali, Roberto Sacchi, Franco Bernini, Augusto Gentilli and Edoardo Razzetti
Repatriations and translocations are among the most frequent actions deployed for conservation of amphibians all over the world. However, very few studies have analysed the effectiveness of these actions. The aims of this study were i) to measure the success of repatriations of Rana latastei carried out within a conservation project in Lombardy (Northern Italy) from 1999 to 2001, and ii) to analyse how the environmental factors affected repatriation success. Eighteen ponds were surveyed from February to April 2006, for an overall of 45 field surveys. Each pond was carefully checked for frogs and egg masses. We classified each pond as newly excavated or pre-existing according to habitat management actions and we measured 16 variables concerning micro- and macro-habitat characteristics, human disturbance and presence of predators. Rana latastei was found in 33.3% of monitored sites and the repatriation outcome of tadpole release did not differ between newly excavated and non managed ponds. Habitat variables influenced the success of repatriations, which increased in sites with higher percentage of woodlands. Finally, repatriation outcome was also negatively influenced by human disturbance and predator occurrence.
Daniele Pellitteri-Rosa, Veronica Maiocchi, Stefano Scali, Luca Racina, Luca Cavigioli, Roberto Sacchi, Mauro Fasola, Paolo Galeotti, Augusto Gentilli, Serena Tettamanti and Fabio Pupin
Photographic identification is a promising marking technique alternative to the toe-clipping, since it is completely harmless, cheap, and it allows long time identification of individuals. Its application to ecological studies is mainly limited by the time consuming to compare pictures within large datasets and the huge variation of ornamentation patterns among different species, which prevent the possibility that a single algorithm can effectively work for more than few species. Scales of Reptiles offer an effective alternative to ornamentations for computer aided identification procedures, since both shape and size of scales are unique to each individual, thus acting as a fingerprint like ornamentation patterns do. We used the Interactive Individual Identification System (I3S) software to assess whether different individuals of two species of European lizards (Podarcis muralis and Lacerta bilineata) can be reliably photographically identified using the pattern of the intersections among pectoral scales as fingerprints. We found that I3S was able to identify different individuals among two samples of 21 individuals for each species independently from the error associated to the ability of the operators in collecting pictures and in digitizing the pattern of intersections among pectoral scales. In a database of 1043 images of P. muralis collected between 2007 and 2008, the software recognized 98% of recaptures within each year, and 99% of the recaptures between years. In addition, 99% and 96% of matches were ranked among the top five, and no more than 5 minutes were needed for digitizing and processing each image. The lepidosis of reptiles is a reliable alternative to ornamentation patterns in photographic identification of reptiles, which can be effectively analysed using the I3S software. This result represents a significant improvement in photographic identification of reptiles since (i) this procedure can be easily extended to most other species of reptiles, (ii) all kind of individuals within a species can be marked (i.e., young, subadults and adults) despite the differences in ornamentation patterns, and (iii) it is the only technique for species, like the western green lizard, which lack a clear ornamentation pattern.