Differences in gene flow in a twofold secondary contact zone of pond turtles in southern Italy (Testudines: Emydidae:Emys orbicularis galloitalica,E. o. hellenica,E. trinacris)

Abstract

Using virtually range-wide sampling for three pond turtle taxa (Emys orbicularis galloitalica,\ud E. o. hellenica, E. trinacris), we analyse gene flow across their southern Italian contact zone.\ud Based on population genetic analyses of 15 highly polymorphic microsatellite loci and a\ud mitochondrial marker, we show that the general genetic pattern matches well with the current\ud taxon delimitation. Yet, single individuals with conflicting genetic identity suggest\ud translocation of turtles by humans. In addition, we identify in south-western France and the\ud vicinity of Rome populations being heavily impacted by introduced turtles. Cline analyses\ud reveal that the major genetic break between E. o. galloitalica and E. o. hellenica corresponds\ud well with the currently accepted intergradation zone in southern Italy. However, introgression\ud is largely unidirectional from E. o. galloitalica into E. o. hellenica. In the distribution\ud range of the latter subspecies, genetic footprints of E. o. galloitalica are evident along most\ud of the Italian east coast. Our results corroborate that E. o. galloitalica was introduced long\ud ago in Corsica and Sardinia and naturalized there. Gene flow between E. orbicularis and\ud E. trinacris is negligible, with the Strait of Messina matching well with the narrow cline centre\ud between the two species. This contrasts with other Mediterranean freshwater turtle species\ud with extensive transoceanic gene flow. Compared to the two subspecies of E. orbicularis,\ud the Sicilian E. trinacris shows an unexpectedly strong population structuring, a finding\ud also of some relevance for conservation. The differences between the two taxon pairs\ud E. orbicularis/E. trinacris and E. o. galloitalica/E. o. hellenica support their current taxonomic\ud classification and make them attractive objects for follow-up studies to elucidate the\ud underlying mechanisms of speciation by comparing their propertie

The good, the bad and the ugly: Emys trinacris, Placobdella costata and Haemogregarina stepanowi in Sicily (Testudines, Annelida and Apicomplexa)

“…(see Marrone et al 2016a). Such an unexpected decoupling might be due to a recent, human-mediated introduction of the leech to Sicily, which would be also supported by the evidence of the presence of introduced specimens of E. orbicularis from Italy in Lago Urio Quattrocchi (Vamberger et al 2015), or to a natural long-range passive dispersal event of the species, which is reported to be able to be dispersed by non-chelonian vertebrates with aquatic afinity (Vamberger and Trontelj 2007, Bielecki et al 2012, Marrone et al 2016a.…”

“…Although it is morphologically similar to E. orbicularis sensu lato (s.l.) (see Fritz et al 2006), molecular taxonomic studies have unambiguously revealed the presence of significant differences between the two species, which are adelphotaxa (Fritz et al 2005, Pedall et al 2011, Vamberger et al 2015. In spite of the biogeographical and evolutionary importance of this chelonian species and the reduction of its populations caused by habitat destruction, pollution and pathogens, E. trinacris was listed in the IUCN Red List as 'Data Deficient' (van Dijk 2009), thus highlighting the need for further studies aimed at its characterising and monitoring of its health status.…”

Some like it cold: the glossiphoniid parasites of the Sicilian endemic pond turtleEmys trinacris(Testudines, Emydidae), an example of ‘parasite inertia’?

“…; Vamberger et al. ). Pond turtles were captured by hand or with the use of baited traps left overnight in concealed sites.…”

“… and Vamberger et al. ;. Each turtle specimen was carefully inspected for the presence of leeches; when these were present, they were collected and fixed in situ in 95% ethanol, and identified according to Minelli ().…”

“… and Vamberger et al. ]. Thermocycling conditions for both primer combinations are outlined in Stuckas et al.…”