Nicola Salomone

Historical biogeography of Tyrrhenian land snails: The Marmorana–Tyrrheniberus radiation (Pulmonata, Helicidae)

The few studies available on Tyrrhenian land snails support high diversification in the Italian Peninsula and groups structured mainly by vicariant events. Here we investigated the phylogeny of a conchologically diversified group of Tyrrhenian land snails assigned to the genera Marmorana and Tyrrheniberus. We constructed a molecular phylogeny by sequencing two commonly used mtDNA genes (cytochrome oxidase I and the large ribosomal subunit). We also carried out conchological and anatomical analysis. Morphological (shell and genitalia) and genetic data (mitochondrial genes) showed paraphyly of Marmorana. Plio-Pleistocene events in the Tyrrhenian area may have structured relationships between species at regional scale while isolation by distance probably played a role in diversification between populations on a local scale. Continental populations experienced dispersal during interglacial periods and fragmentation and reduction during the dry cold climatic phases. Areas inhabited by Apennine Marmorana could represent relict and/or glacial refugia, with extinction in some areas along the Apennines and survival in the south. The results support a reassessment of taxonomy both at genus and species level and call for further analysis.

Investigation on the taxonomic status of Steganacarus magnus and Steganacarus anomalus (Acari: Oribatida) using mitochondrial DNA sequences

To test the previously suggested synonymization of S. anomalus with the older S. magnus, a fragment of the mitochondrial COI gene was amplified via the polymerase chain reaction and sequenced. The sequence variation was examined in a total of 327 base pairs for four steganacarid mite populations, two of which belong to S. anomalus, one to S. magnus and one to S. hirsutus. The sequence variation suggests that S. magnus and S. anomalus are not distinct species and that the population from Fioreta (Siena) is more similar to that from Apulia than to the nearer population from the Apuan Alps. The results show the usefulness of this molecular approach as a tool for determining taxonomic status and for suggesting faunistic movements in the past millions of years.

Taxonomic revision of Amerus troisi (Berlese, 1883) (Acari, Oribatida, Ameridae) using morphological and biochemical characters

This paper redescribes the classical taxon Amerus troisi (Berlese, 1883) on the basis of topotypical material. A new species, Amerus cuspidatus, characterized by short interlamellar setae and a distinct rostral morphology, is also described. In spite of overlapping biogeographical distributions, biochemical analysis indicates that the two Amerus species are clearly differentiated.

Genetic diversity in the Carabodes marginatus species group (Acarida, Oribatida, Carabodidae) as inferred from allozymes

Ten populations representing four species of the ‘Carabodes marginatus’ group, as C. marginatus, C. affinis, C. quadrangulus and C. montanus from central Italy have been studied for genetic variation at 16 enzymatic loci by electrophoresis. Morphotypes close to C. marginatus but easily distinguishable by the shorter marginal notogastral setae were also included in the analysis to evaluate their systematic status. Carabodes arduinii, a very different species from the ‘coriaceus’ group, was employed as an out-group. Phylogenetic relationships among different species were studied and inferred data demonstrated that cladogenetic events occurred, even though rates of molecular and morphological evolution do not correlate. Morphotypes related to C. marginatus were genetically very close to the type specimens, but a different pattern of allele frequency was observed in sympatric populations of the two setal forms. Possible explanations for this finding are suggested in relation to historical processes. The rate of gene flow among populations of the two morphs was estimated by both Wrights F st and Slatkins Nm methods. These two different procedures yielded contradictory results.

Genetic and Morphological Analysis of Some European Species of the “coriaceus group” of Carabodes (Acari, Oribatida, Carabodidae) and Description of C. tyrrhenicus sp. nov.

Abstract The oribatid mite Carabodes reticulatus Berlese, 1913 is redescribed from typical and topotypical material. A new species, C. tyrrhenicus , widespread in Sardinia and other Tyrrhenian islands, is also described on the basis of morphological evidence. Scanning electron microscopy was used to study intra- and inter-specific variation, in order to determine diagnostic characters. The morphology-based taxonomy was tested through allozyme analysis of the two species and of two closely related species, namely C. coriaceus C. L. Koch, 1836 and C. arduinii Valle, 1955. Allozyme data are largely congruent with morphological evidence, indicating that the four entities represent well-differentiated evolutionary lineages. Molecular results show large inter-specific genetic differentiation, suggesting that these taxa arose from ancient cladogenetic events.

The radiation of alopiine clausiliids in the Sicilian Channel (Central Mediterranean): phylogeny, patterns of morphological diversification and implications for taxonomy and conservation of Muticaria and Lampedusa

The phylogeny, biogeography and taxonomy of the alopiine clausiliids of the Sicilian Channel, belonging to the genera Lampedusa and Muticaria, were investigated using morphological (shell characters and anatomy of the reproductive system) and genetic (sequencing of a fragment of the mitochondrial large ribosomal subunit 16S rRNA, and the nuclear internal transcriber spacer 1, ITS-1 rRNA) data. Classically, the genus Lampedusa includes three species: L. imitatrix and L. melitensis occurring in circumscribed localities in western Malta and on the islet of Filfla, and L. lopadusae on Lampedusa and Lampione. The genus Muticaria includes two species in southeastern Sicily (M. siracusana and M. neuteboomi) and one in the Maltese islands (M. macrostoma), which is usually subdivided into four entities based on shell characters (macrostoma on Gozo, Comino, Cominotto and central-eastern Malta; mamotica in southeastern Gozo; oscitans on Gozo and central-western Malta; scalaris in northwestern Malta). These have sometimes been considered as subspecies and sometimes as mere morphs. The Lampedusa of Lampedusa and Lampione form a well distinct clade from those of the Maltese Islands. The population of Lampione islet is a genetically distinct geographic form that deserves formal taxonomic recognition (as L. nodulosa or L. l. nodulosa). The Lampedusa of Malta are morphologically distinct evolutionary lineages with high levels of genetic divergence and are confirmed as distinct species (L. imitatrix and L. melitensis). The Muticaria constitute a clearly different monophyletic clade divided into three geographical lineages corresponding to the Sicilian, Maltese and Gozitan populations. The Sicilian Muticaria form two morphologically and genetically distinguishable subclades that may either be considered subspecies of a polytypic species, or two distinct species. The relationships of Maltese and Gozitan Muticaria are complex. Two of the three Maltese morphotypes resulted monophyletic (oscitans and scalaris) while the other was separated in two lineages (macrostoma); however this picture may be biased as only few samples of macrostoma were available to study. The Gozitan morphotypes (macrostoma, mamotica and oscitans) where resolved as polyphyletic but with clear molecular evidence of mixing in some cases, indicating possible relatively recent differentiation of the Gozitan Muticaria or repetitive secondary contacts between different morphotypes. Definitive taxonomic conclusions from these results are premature. Maltese Muticaria could be subdivided into three taxa according to morphological and molecular data (M. macrostoma or M. m. macrostoma, M. oscitans or M. m. oscitans and M. scalaris or M. m scalaris). Gozitan Muticaria could be considered a distinct polytypic species (for which the oldest available name is Muticaria mamotica) subdivided into subspecies showing a morphological range from macrostoma-like to mamotica-like and oscitans like. Only the two Maltese species of Lampedusa are legally protected (by the European Union’s ‘Habitats Directive’ and Maltese national legislation). The present study has shown that the alopiine clausiliids of the Sicilian Channel constitute a number of genetically and/or morphologically distinct populations that represent important pools of genetic diversity, with, in some cases, a very circumscribed distribution. As such, these populations deserve legal protection and management. It is argued that without formal taxonomic designation, it would be difficult to extend international legal protection to some of the more threatened of these populations.

Mitochondrial DNA variation and phylogeography of Steganacarus on Tenerife (Canary Islands)

Sequences from a fragment of the mitochondrial cytochrome oxidase I gene were used to analyze the population structure and phylogeography of the genus Steganacarus from Tenerife. The island has an oceanic origin; it became a single entity only in the Pleistocene (~2.0 Ma) as a result of the volcanic evolution of the Teide-Pico Viejo central complex which joined the earlier three massifs of Anaga, Roque del Conde and Teno. The mtDNA haplotype distribution and the estimates of sequence divergence among populations of S. carlosi reveal the presence of different lineages with strong phylogeographic structures which reflect the disjunct volcanic evolution of the island. The high levels of intra-specific differentiation suggest that biogeographic boundaries have an impact on the genetic structure of this low dispersal genus by limiting gene-flow among populations and determining isolated demes in which mutation and genetic drift may facilitate differentiation.