ABSTRACT
European marbled newts come in two species that have abutting ranges. The northern species, Triturus marmoratus, is found in France and the northern part of the Iberian Peninsula, whereas the southern species, T. pygmaeus, is found in the southwestern corner of the Iberian Peninsula. We study the intraspecific genetic differentiation of the group because morphological data show geographical variation and because the Iberian Peninsula is a recognized center of speciation and intraspecific genetic diversity for all kinds of organisms, amphibians included. We use target enrichment by sequence capture to generate c. 7 k nuclear DNA markers. We observe limited genetic exchange between the species, which confirms their distinctiveness. Both species show substantial genetic structuring that is only in part mirrored by morphological variation. Genetically differentiated groups are found in the south (T. marmoratus) and west (T. pygmaeus) of the species ranges. Our observations highlight the position of the Iberian Peninsula as a hotspot for genetic differentiation.
ABSTRACT
When two putatively cryptic species meet in nature, hybrid zone analysis can be used to estimate the extent of gene flow between them. Two recently recognized cryptic species of banded newt (genus Ommatotriton) are suspected to meet in parapatry in Anatolia, but a formal hybrid zone analysis has never been conducted. We sample populations throughout the range, with a focus on the supposed contact zone, and genotype them for 31 nuclear DNA SNP markers and mtDNA. We determine the degree of genetic admixture, introgression, and niche overlap. We reveal an extremely narrow hybrid zone, suggesting strong selection against hybrids, in line with species status. The hybrid zone does not appear to be positioned at an ecological barrier, and there is significant niche overlap. Therefore, the hybrid zone is best classified as a tension zone, maintained by intrinsic selection against hybrids. While the two banded newt species can evidently backcross, we see negligible introgression and the pattern is symmetric, which we interpret as supporting the fact that the hybrid zone has been practically stationary since its origin (while extensive hybrid zone movement has been suggested in other newt genera in the region). Our study illustrates the use of hybrid zone analysis to test cryptic species status.
ABSTRACT
The sea urchin Diadema setosum is an ecological key species across its range, particularly on coral reefs. In 2006 D. setosum was first observed in the Mediterranean Sea, and since, it has proliferated to occupy the entire Levantine Basin. Here we report the mass mortality of the invasive D. setosum in the Mediterranean Sea. This is the first report of D. setosum mass mortality. The mortality spans over 1000 km along the Levantine coast of Greece and Turkey. The current mortality shows similar pathologies to previously reported Diadema mass mortality events, suggesting pathogenic infection as the cause of mortalities. Maritime transport, local currents, and fish predation of infected individuals may distribute pathogens at varying geographical scales. Due to the proximity of the Levantine Basin to the Red Sea, the risk of pathogen transport to the native Red Sea D. setosum population is imminent-with potentially catastrophic consequences.
ABSTRACT
Technological developments now make it possible to employ many markers for many individuals in a phylogeographic setting, even for taxa with large and complex genomes such as salamanders. The banded newt (genus Ommatotriton) from the Near East has been proposed to contain three species (O. nesterovi, O. ophryticus and O. vittatus) with unclear phylogenetic relationships, apparently limited interspecific gene flow and deep intraspecific geographic mtDNA structure. We use parallel tagged amplicon sequencing to obtain 177 nuclear DNA markers for 35 banded newts sampled throughout the range. We determine population structure (with Bayesian clustering and principal component analysis), interspecific gene flow (by determining the distribution of species-diagnostic alleles) and phylogenetic relationships (by maximum likelihood inference of concatenated sequence data and based on a summary-coalescent approach). We confirm that the three proposed species are genetically distinct. A sister relationship between O. nesterovi and O. ophryticus is suggested. We find evidence for introgression between O. nesterovi and O. ophryticus, but this is geographically limited. Intraspecific structuring is extensive, with the only recognized banded newt subspecies, O. vittatus cilicensis, representing the most distinct lineage below the species level. While mtDNA mostly mirrors the pattern observed in nuclear DNA, all banded newt species show mito-nuclear discordance as well.
Subject(s)
Gene Flow , Phylogeny , Salamandridae , Animals , Bayes Theorem , DNA, Mitochondrial/genetics , Genetic Structures , Phylogeography , Salamandridae/classification , Salamandridae/genetics , Sequence Analysis, DNAABSTRACT
Invasive alien species have been increasingly acknowledged as a major threat to native biodiversity and ecosystem services, while their adverse impacts expand to human health, society and the economy on a global scale. Insects represent one of the most numerous alien organismic groups, accounting for about one fifth of their total number. In Greece, a large number of alien insects have been identified, currently reaching 469 species. In recent decades, the contribution of citizen science towards detecting and mapping the distribution of alien insects has been steeply increasing. Addressing the need for up-to-date information on alien species as well as encouraging public participation in scientific research, the Alientoma website-derived from "alien" and the Greek word "entoma", meaning insects, is presented. The website aims towards providing updated information on alien species of insects to the public as well as the scientific community, raising awareness about biological invasions and addressing their distribution and impacts inter alia. By maintaining a dynamic online database alongside a strong social media presence since its launch, Alientoma has attracted individuals mainly from Greece and Cyprus, interacting with the website through a total of 1512 sessions. Alientoma intends to establish a constantly increasing network of citizen scientists and to supplement early detection, monitoring and management efforts to mitigate the adverse impacts of alien insects in Greece.
ABSTRACT
Species of the genus Helopelius Reitter, 1922 (type species: Stenomax aeneipennis Allard, 1876) were known from Rhodes and North Africa. We found that two species described from Rhodes belong to the genus Stenohelops Reitter, 1922, and Helopelius can be interpreted as a subgenus within latter, guided by the article 23.2 of ICZN. The following synonyms are proposed: Helopelius, stat. n. (from genus to subgenus) = Stenomaleis Español, 1957, syn. n.; Stenohelops Reitter, 1922 = Gunarellus Reitter, 1922, syn. n.; Stenohelops (Helopelius) aeneipennis (Allard, 1876) = Helopelius disgregus Reitter, 1922, syn. n., = Gunarus gayirbegi Nabozhenko Keskin, 2009, syn. n. As a result, the following species are transferred from the former genus Helopelius to the genus Stenohelops: Stenohelops (Helopelius) nodifer (Kraatz, 1880), comb. n.; Stenohelops (Helopelius) otini (Antoine, 1949), comb. n.; Stenohelops (Helopelius) subsinuatus (Antoine, 1951), comb. n.; Stenohelops (Helopelius) verrucosus (Vauloger de Beaupré, 1900), comb. n.; Stenohelops (Helopelius) zaianus (Antoine, 1949), comb. n. Thus, the subgenus Helopelius contains 11 species from three isolated geographical exclaves: Western Mediterranean, Eastern Mediterranean and China. Lectotypes of Stenomax aeneipennis Allard, 1876, Helops gratus J. Frivaldszky, 1894 and Cylindrinotus (Helopelius) disgregus Reitter, 1922 are designated. Data on fossil species of the genus and the allied extinct taxa, as well as on bionomics of extant species of the subgenus Helopelius are presented. The check-list for extant and extinct species of Stenohelops is given.