Historical biogeography of Tyrrhenian land snails: The Marmorana-Tyrrheniberus radiation (Pulmonata, Helicidae)
University of Siena, Dipartimento di Scienze Ambientali, Via P.A. Mattioli 4, 53100 Siena, Italy. Molecular Phylogenetics and Evolution
(Impact Factor: 3.92).
12/2009; 55(1):26-37. DOI: 10.1016/j.ympev.2009.11.024
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.
Available from: Nikolaos Psonis
- "The numbers on the maps correspond to the sample code of Appendix A. All the morphological species of the three (sub)genera found in Greece are presented in theses maps with different shapes and shadows. 2012, 2010; Mumladze et al., 2013; Puizina et al., 2013; Riel et al., 2005) or Ariantinae from other areas (Murella muralis; Fiorentino et al., 2013, 2010; Marmorana and Tyrrheniberus; Fiorentino et al., 2008; and Arianta arbustorum; Gittenberger et al., 2004; Haase et al., 2013; Haase and Misof, 2009). The lack of studies on Ariantinae from southern Balkans shows that there is an urgent need to focus on that area and, by including endemic species, to explore the phylogeny and the phylogeography of the representative species groups there, resulting in a more robust and complete scenario for the evolutionary history of the Ariantinae family. "
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ABSTRACT: The land snails of the genus Chilostoma Fitzinger, 1833 that includes, in Greece, the (sub)genera Cattania, Josephinella and Thiessea, are highly diversified and present high levels of endemism. However, their evolutionary history is unknown and their taxonomy is complex and continuously revised. The aim of this study is to investigate the phylogenetic relationships of the lineages of the genus Chilostoma distributed in Greece based on partial DNA sequences of two mitochondrial DNA (16S rRNA and COI) genes. Partial sequences of one nuclear gene (ITS1) representing the major mitochondrial lineages were also analysed. The phylogenetic trees revealed three distinct major clades that correspond to the three (sub)genera. Several taxonomical incongruencies were made obvious, thus, raising questions about the "true" number of species in each clade, while rendering a taxonomic re-evaluation necessary. From a phylogeographic point of view, it seems that the three major phylogenetic clades were separated in the late Miocene. They started differentiating into distinct species during the Pliocene and Pleistocene through several vicariance and dispersal events.
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Available from: Errol Véla
- "When such human-mediated dispersal events occur, they may greatly complicate phylogeographical reconstruction [e.g. Fiorentino et al. (2010), Pfenninger et al. (2010) and Jesse, Véla & Pfenninger (2011) for recent, possibly anthropogenic, dispersion events in the land snail genus Marmorana and the land snail Tudorella sulcata]. Genista cilentina is also similar to G. numidica from a morphological standpoint, and the hypothesis of 'accidental importation' from Algeria in historical times was also formulated on morphological grounds (De Marco et al., 1987; De Castro et al., 2002; Bacchetta et al., 2011, 2012). "
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ABSTRACT: The present investigation investigated the genetic structure of a monophyletic group of endemic species belonging to the Genista ephedroides species However, although genetic diversity within populations was low [(hS = 0.132 (± 0.056)], a high level of total plastid DNA diversity [hT = 0.866 (± 0.042)] was detected, and analysis of molecular variance indicated that variation is almost exclusively expressed among populations (95.25%). The plastid microsatellites identify two groups of taxa, one including Sardinian taxa and populations of G. tyrrhena subsp. pontiana and the other including two subgroups, one of which includes Sicilian/Aeolian elements and the other with G. numidica/G. cilentina and G. dorycnifolia. Results allow us to consider G. cilentina as originating by recent anthropogenic dispersal and G. tyrrhena subsp. pontiana as a possible stabilized hybrid between local plants and members of the Sardinian group contributing the maternal lineage. The evolutionary history of the group possibly results from the effects of ancient events fostering geodispersal and range contraction, followed by more recent long-range dispersal or geodispersion over Pleistocenic land bridges.
- "Unfortunately, dating of the colonization from sequence divergence is not possible; the notorious lack of internal calibration points within Helicidae prevents meaningful use of a molecular clock (Fiorentino et al., 2010; Kotsakiozi et al., 2012). However, while crossing of the Adriatic basin during the period of low sea recession seems most likely, chance long-range dispersal across the sea cannot be completely ruled out. "
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ABSTRACT: Helix is a genus of large Western Palaearctic land snails, particularly diverse in the Mediterranean region. Despite size and attractiveness of its members, it has an unsettled taxonomy, and no data are available on its intrageneric phylogenetic relationships. One of the problematic Helix taxa is the widely distributed, economically important, and conchologically very variable H. lucorum. Two distinct forms may be encountered under this name in the Apennine Peninsula: a typical one in the north, and a form originally described as Helix straminea in central and southern Italy. To evaluate the status of H. straminea and its relationships to Italian and Balkan Helix fauna, we combined shell morphology, geometric morphometrics, and phylogenetic analysis based on two mitochondrial genes. Distribution data were improved by drawing information from unambiguously identifiable photographs posted online. Based on our results, Helix straminea is redescribed as a separate species, and we find it to have a disjunctive trans-Adriatic range with closest relatives in the western Balkans. We provide an insight into relationships and intraspecific variability within Helix, a first step towards a comprehensive revision of the genus. On the example of Italian Helix fauna, we demonstrate how understanding of snail zoogeography may change with improving taxonomy.
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