Sinos Giokas

Phylogenetic analysis and biogeography of Aegean taxa of the genus Dendarus (Coleoptera: Tenebrionidae)

The genus Dendarus Latr. is distributed throughout the Mediterranean basin with numerous species in the Aegean islands. This paper presents a phylogenetic analysis and the biogeography of most taxa present in the area. Phylogenetic analysis of two outgroup and 25 ingroup taxa based on adult morphology, including 50 characters and 119 character states, produced two equally parsimonious trees (tree length = 148, C.I. = 0.42, R.I. = 0.70, R.C. = 0.294). These trees provide strong support for the monophyly of Dendarus and also define four species groups: the foraminosus group, present mainly on the island of Crete; the rhodius group, present in Dodecanese islands, the sinuatus group present in the central Aegean islands, and another group consisting of taxa from mainland Greece (D. messenius, D. caelatus, D. tenellus, and D. plicatulus paganettii). All area cladograms produced by Compatibility Component Analysis, Brooks Parsimony Analysis, and especially by Component Analysis, correspond quite closely to the hypothesized palaeogeographic history of the studied area and therefore partly support the idea of a vicariant evolution of Dendarus taxa in this region. We distinguished certain monophyletic groups distributed (with some exceptions) within well-defined geographical and palaeogeographical regions of the Aegean. However, we found certain inconsistencies (with Reconciled Tree Analysis) that are probably the result of dispersal, extinction, or duplication events that are independent of the sequence of vicariance events.

Neogene climatic oscillations shape the biogeography and evolutionary history of the Eurasian blindsnake.

Typhlops vermicularis is the only extant scolecophidian representative occurring in Europe. Its main distribution area, the eastern Mediterranean, has a complicated geological and climatic history that has left an imprint on the phylogenies and biogeography of many taxa, especially amphibians and reptiles. Since reptiles are sensitive indicators of palaeogeographical and palaeoclimatic events, we investigated the intraspecific genealogy of T. vermicularis in a phylogeographical framework. A total of 130 specimens were analyzed, while the use of formalin and ethanol as preservatives called for a special treatment of the samples. Partial sequences of two mitochondrial (12S and ND2) and one nuclear (PRLR) marker were targeted and the results of the phylogenetic analyses (NJ, ML and BI) and the parsimony-network revealed the existence of 10 evolutionary significant units within this species. In combination with the results of the dispersal-vicariance analysis, we may conclude that the Eurasian blindsnake has encountered a sequence of extinction events, followed by secondary expansion from refugia. Estimation of divergence times showed that severe climatic changes between significantly wetter and drier conditions in the Late Neogene have played a key role on the evolutionary and biogeographical history of T. vermicularis. Additionally, both markers (mtDNA and nDNA) distinguished a largely-differentiated evolutionary lineage (Jordan and south Syria), which could even be reckoned as a full species. Our study reveals the existence of cryptic evolutionary lineages within T. vermicularis, which calls for further attention both on the protection of intraspecific varieties and the respective geographic areas that hold them.

Mitochondrial phylogeny and biogeographic history of the Greek endemic land-snail genus Codringtonia Kobelt 1898 (Gastropoda, Pulmonata, Helicidae).

The aim of this work was to infer the phylogeny of the Greek endemic land-snail genus Codringtonia Kobelt 1898, estimate the time frame of the radiation of the genus, and propose a biogeographic scenario that could explain the contemporary distribution of Codringtonia lineages. The study took place in the districts of Peloponnese, Central Greece and Epirus of mainland Greece. Sequence data originating from three mtDNA genes (COI, COII, and 16S rDNA) were used to infer the phylogeny of the eight nominal Codringtonia species. Furthermore, the radiation time-frame of extant Codringtonia species was estimated using a relaxed molecular clock analysis and mtDNA substitution rates of land snails. The phylogenetic analysis supported the existence of six Codringtonia lineages in Greece and indicated that one nominal species (Codringtonia neocrassa) might belong to a separate genus distantly related to Codringtonia. The time frame of differentiation of Codringtonia species was placed in the Late Miocene-Pleistocene epoch. The dispersal-vicariance analysis performed indicated that most probably Codringtonia exhibited a north-to-south spread with the ancestral area being that of central Greek mainland, accompanied with duplication (speciation) and vicariance events.

Predator-prey interactions between shell-boring beetle larvae and rock-dwelling land snails.

Drilus beetle larvae (Coleoptera: Elateridae) are specialized predators of land snails. Here, we describe various aspects of the predator-prey interactions between multiple Drilus species attacking multiple Albinaria (Gastropoda: Clausiliidae) species in Greece. We observe that Drilus species may be facultative or obligate Albinaria-specialists. We map geographically varying predation rates in Crete, where on average 24% of empty shells carry fatal Drilus bore holes. We also provide first-hand observations and video-footage of prey entry and exit strategies of the Drilus larvae, and evaluate the potential mutual evolutionary impacts. We find limited evidence for an effect of shell features and snail behavioral traits on inter- and intra-specifically differing predation rates. We also find that Drilus predators adjust their predation behavior based on specific shell traits of the prey. In conclusion, we suggest that, with these baseline data, this interesting predator-prey system will be available for further, detailed more evolutionary ecology studies.

Disassociation between weak sexual isolation and genetic divergence in a hermaphroditic land snail and implications about chirality

Examination of the association between reproductive isolation and genetic divergence in a variety of organisms is essential for elucidating the mechanisms causing speciation. However, such studies are lacking for hermaphrodites. We measured premating (sexual) isolation in species pairs of the hermaphroditic land snail Albinaria and we compared it with their genetic divergence. We did not find substantial sexual isolation barriers between the species studied. The absence of strong sexual isolation between species implies its minor effect in the evolution of this genus, because distributional, population and life‐history characteristics of Albinaria make mate‐choice possibly redundant. Furthermore, we found disassociation between genetic divergence and sexual isolation, suggesting that they do not form necessarily a cause–effect duet. However, Albinaria voithii, the only dextral Albinaria species, shows strong sexual isolation against the other sinistral species. We discuss whether change in coiling either has triggered instantaneous speciation, or is an example of character displacement.

Fine scale spatial genetic structure of two syntopic newts across a network of ponds: implications for conservation

In this study we used genetic approaches to assess the influence of landscape features on the dispersal patterns and genetic structure of two newt species (Triturus macedonicus and Lissotriton vulgaris) living syntopically in a network of ponds. Multilocus genotypes were used to detect and measure genetic variation patterns, population genetic structure and levels of gene flow. We interpret results on the basis of the different dispersal properties of the two species and explored the influence of certain landscape features, such as road and channel networks, on population connectivity. We found marked differences in the spatial genetic patterns of the respective species, which can be explained by their different dispersal properties. The road network seems to act as a barrier to dispersal in the overland dispersing L. vulgaris, while the channel network maintains connectivity in the aquatic dispersing T. macedonicus. The simultaneous and comparative consideration of species in a given area offers a much better understanding of the processes that govern population dynamics and persistence, providing valuable knowledge useful in conservation and management design.

Phylogenetic position, origin and biogeography of Palearctic and Socotran blind-snakes (Serpentes: Typhlopidae)

The majority of the family Typhlopidae occurs in the Neotropic, Australasian, Indo-Malayan and Afrotropic ecoregions. They show a restricted distribution in the western Palearctic, where they include few native species, i.e. Rhinotyphlops simoni, R. episcopus and Typhlops vermicularis. A unique species among typhlopids is T. socotranus, found in Socotra, one of the most endemic-rich archipelagoes. In this study we determine the phylogenetic position of the above mentioned species and discuss their systematics, origin and biogeography. For this purpose we use three protein-coding nuclear markers (AMEL-amelogenin, BDNF-brain-derived neurotrophic factor and NT3-neurotrophin 3) to construct a time-calibrated phylogeny of the family Typhlopidae. Our results show that T. socotranus is a sister-species to T. vermicularis, while R. simoni and R. episcopus are sister-species to each other and are found within the African clade of the family, although they are geographically distributed in west Asia. Additionally we discuss several hypotheses on their origin, as well as the occurence of typhlopids in Eurasia.

Phylogeography and genetic structure of the slow worms Anguis cephallonica and Anguis graeca (Squamata: Anguidae) from the southern Balkan Peninsula

Two slow worm species are distributed at the southernmost part of the Balkan Peninsula: Anguis cephallonica, an endemic of the Peloponnese and the islands Zakynthos, Ithaki and Kephallonia, and A. graeca. Here, we investigate the intraspecific genetic diversity of A. cephallonica from the Peloponnese and Kephallonia and analyse A. graeca, from the northern Peloponnese, where it is found in sympatry with A. cephallonica. MtDNA and nDNA phylogenetic analyses confirm the genetic similarity of Peloponnesian and Kephallonian populations of A. cephallonica and reveal significant mtDNA genetic variation within it, probably related to the occurrence of multiple subrefugia in the Peloponnese. Peloponnesian A. graeca populations are genetically similar to non-Peloponnesian conspecifics implying recent dispersal to the Peloponnese. In contrast to the genetic markers, morphological characteristics (such as the number of mid-body scale-rows) failed to distinguish between Peloponnesian A. cephallonica and A. graeca. Although the former species is believed to be well-differentiated from its congeneric taxa, a thorough morphological study is needed.

Nonrandom variation of morphological traits across environmental gradients in a land snail

Morphological variation is often attributed to differential adaptations to diverse habitats, but adaptations to a similar environment do not necessarily result in similar phenotypes. Adaptations for water and heat budget are crucial for organisms living in arid habitats, and in snails, variation in shell morphology has been frequently attributed to selection by stressful environmental factors. However, their phenotypic divergence often is not accompanied by a relevant niche differentiation and consistent relationships with environmental correlates are lacking. In the pulmonate genus Albinaria, there is great size and shape variation between and within species, and there are two major shell sculpture morphotypes, ribbed and smooth. We used 62 populations of 28 Albinaria species, taking into account their phylogeny, to examine the variation of shell traits (sculpture, size, shape), their effect on water and heat budget, and their association with geographical and climatic gradients. We found unambiguous size and shape discrimination between the two morphotypes. Ribbed shells are lighter, taller, and slimmer and have a smaller aperture than the smooth ones. Moreover, significant correlations between shell traits and heat/moisture budget and climate/geography were revealed. Ribbed and taller shells retain more water on their shell surface, and on the other hand, smooth shells exhibit lower water permeability. Therefore, two strategies are being used to prevent water loss, active retention or resistance to loss. Consequently, different alternative solutions evolved and were retained as responses to the same stressful factor by the two distinct shell morphotypes. Larger shells occur in southern latitudes, mostly on islands, and at sites where there is a shortage of rainfall. Therefore, the variation of the examined traits is nonrandom with respect to location and to climate and their evolution can be attributed to selection by environmental factors, with water availability being the key driving agent of body-size variation.

A newt does not change its spots: using pattern mapping for the identification of individuals in large populations of newt species

The correct identification of individuals is a requirement of capture-mark-recapture (CMR) methods, and it is commonly achieved by applying artificial marks or by mutilation of study-animals. An alternative, non-invasive method to identify individuals is to utilize the patterns of their natural body markings. However, the use of pattern mapping is not yet widespread, mainly because it is considered time consuming, particularly in large populations and/or long-term CMR studies. Here we explore the use of pattern mapping for the identification of adult individuals in the alpine (Ichthyosaura alpestris) and smooth (Lissotriton vulgaris) newts (Amphibia, Salamandridae), using the freely available, open-source software Wild-ID. Our photographic datasets comprised nearly 4000 captured animals’ images, taken during a 3-year period. The spot patterns of individual newts of both species did not change through time, and were sufficiently varied to allow their individual identification, even in the larger datasets. The pattern-recognition algorithm of Wild-ID was highly successful in identifying individual newts in both species. Our findings indicate that pattern mapping can be successfully employed for the identification of individuals in large populations of a broad range of animals that exhibit natural markings. The significance of pattern-mapping is accentuated in CMR studies that aim in obtaining long-term information on the demography and population dynamics of species of conservation interest, such as many amphibians facing population declines.