Genetic Variability and the Potential Range of Darevskia rostombekowi in Transcaucasia

Abstract— The results of the analysis of the genetic variability of parthenogenetic Darevskia rostombekowi (Darevsky, 1957) species using four microsatellite-containing loci are presented. Based on 118 records with geographical coordinates of the presence of this species in Transcaucasia, the maps of potential range were created. The analysis of the genetic structure of populations demonstrated that despite the established multiclonality (seven clonal lines in four populations), D. rostombekowi was formed as a result of a single act of hybridization between closely related bisexual species. The predicted distribution of D. rostombekowi using the modelling of potential range revealed new suitable habitats, where the presence of the species has not been reported previously. The results of this study and the absence of multiple acts of hybridization during the formation of these clones may indicate a regression of population size of the species. Consequently, the estimation of the conservation status of this parthenogenetic species seems to be justified.

Diversity in Pacific Slender-Toed Geckos, Nactus pelagicus Complex (Reptilia: Squamata), of New Guinea and Adjacent Islands

The diversity within the genus <i>Nactus</i> is slight in comparison to the other Australasian genus of narrow-toed geckos (<i>Cyrtodactylus</i>). The latter now has more than 290 species, with over half of these species newly described in the twenty-first century. In contrast, prior to this study, 12 <i>Nactus </i>species were recognized formally in the recent herpetological literature: three species in the Mascarene Islands, two in the Pacific Islands, three in Australia, and six in New Guinea and associated island groups. Three of these New Guinea species are miniature (snout–vent length ≤ 40 mm) species, and three are in the <i>pelagicus</i> complex; with the exception of the recently described <i>N. kunan</i>, all other New Guinean populations were labeled <i>N. pelagicus</i> even though they were known to be bisexual species and differed from the unisexual <i>N. pelagicus </i>of Oceania. Considering only bisexual New Guinean “<i>pelagicus</i>,” my morphological analyses recognize 24 distinct populations for which I provide new names or resurrected species names from synonymies. Of these 24, two species are extralimital (Morotai and Kei Islands). The sampling of <i>Nactus</i> in Indonesia Papua is very poor, with only one specimen from the base of the Vogelkop, two from south coast drainages, and more than a dozen from islands from the east coast of Cenderawasih Bay; the remainder derive from Papua New Guinea (PNG). The Indonesia Papua populations represent four species, two of which are shared with PNG. Papua New Guinea thus has a total of 20 species, varying from widespread species (e.g., north coast of main Papua to the Sepik-Ramu area) to a single locality in Madang or single islands in the Louisiade Archipelago. Most distributions of the PNG species match at least one other PNG anuran or reptile species. The greatest diversity of PNG species occurs in Madang Province to Huon Peninsula and the Milne Bay mainland with sympatry in both areas. The “<i>pelagicus</i> complex” of species is herein confirmed to be polyphyletic. In spite of its use in this study, its subsequent use should be restricted to the unisexual species and their parental species, of which only one (<i>N. multicarinatus</i>) is known. The preceding represents a subgroup within the larger clade of Australian and New Guinean bisexual species. For the present, I do not recommend a name for this group because a molecular phylogenetic analysis will be required to identify the cladogenesis of the <i>Nactus</i> species.

Diversity in Pacific Slender-Toed Geckos, Nactus pelagicus Complex (Reptilia: Squamata), of New Guinea and Adjacent Islands

The diversity within the genus <i>Nactus</i> is slight in comparison to the other Australasian genus of narrow-toed geckos (<i>Cyrtodactylus</i>). The latter now has more than 290 species, with over half of these species newly described in the twenty-first century. In contrast, prior to this study, 12 <i>Nactus </i>species were recognized formally in the recent herpetological literature: three species in the Mascarene Islands, two in the Pacific Islands, three in Australia, and six in New Guinea and associated island groups. Three of these New Guinea species are miniature (snout–vent length ≤ 40 mm) species, and three are in the <i>pelagicus</i> complex; with the exception of the recently described <i>N. kunan</i>, all other New Guinean populations were labeled <i>N. pelagicus</i> even though they were known to be bisexual species and differed from the unisexual <i>N. pelagicus </i>of Oceania. Considering only bisexual New Guinean “<i>pelagicus</i>,” my morphological analyses recognize 24 distinct populations for which I provide new names or resurrected species names from synonymies. Of these 24, two species are extralimital (Morotai and Kei Islands). The sampling of <i>Nactus</i> in Indonesia Papua is very poor, with only one specimen from the base of the Vogelkop, two from south coast drainages, and more than a dozen from islands from the east coast of Cenderawasih Bay; the remainder derive from Papua New Guinea (PNG). The Indonesia Papua populations represent four species, two of which are shared with PNG. Papua New Guinea thus has a total of 20 species, varying from widespread species (e.g., north coast of main Papua to the Sepik-Ramu area) to a single locality in Madang or single islands in the Louisiade Archipelago. Most distributions of the PNG species match at least one other PNG anuran or reptile species. The greatest diversity of PNG species occurs in Madang Province to Huon Peninsula and the Milne Bay mainland with sympatry in both areas. The “<i>pelagicus</i> complex” of species is herein confirmed to be polyphyletic. In spite of its use in this study, its subsequent use should be restricted to the unisexual species and their parental species, of which only one (<i>N. multicarinatus</i>) is known. The preceding represents a subgroup within the larger clade of Australian and New Guinean bisexual species. For the present, I do not recommend a name for this group because a molecular phylogenetic analysis will be required to identify the cladogenesis of the <i>Nactus</i> species.

Genotypic similarities among the parthenogenetic Darevskia rock lizards with different hybrid origins

Background The majority of parthenogenetic vertebrates derive from hybridization between sexually reproducing species, but the exact number of hybridization events ancestral to currently extant clonal lineages is difficult to determine. Usually, we do not know whether the parental species are able to contribute their genes to the parthenogenetic vertebrate lineages after the initial hybridization. In this paper, we address the hypothesis, whether some genotypes of seven phenotypically distinct parthenogenetic rock lizards (genus Darevskia) could have resulted from back-crosses of parthenogens with their presumed parental species. We also tried to identify, as precise as possible, the ancestral populations of all seven parthenogens. Results We analysed partial mtDNA sequences and microsatellite genotypes of all seven parthenogens and their presumed ansectral species, sampled across the entire geographic range of parthenogenesis in this group. Our results confirm the previous designation of the parental species, but further specify the maternal populations that are likely ancestral to different parthenogenetic lineages. Contrary to the expectation of independent hybrid origins of the unisexual taxa, we found that genotypes at multiple loci were shared frequently between different parthenogenetic species. The highest proportions of shared genotypes were detected between (i) D. sapphirina and D. bendimahiensis and (ii) D. dahli and D. armeniaca, and less often between other parthenogens. In case (ii), genotypes at the remaining loci were notably distinct. Conclusions We suggest that both observations (i-ii) can be explained by two parthenogenetic forms tracing their origin to a single initial hybridization event. In case (ii), however, occasional gene exchange between the unisexual and the parental bisexual species could have taken place after the onset of parthenogenetic reproduction. Indeed, backcrossed polyploid hybrids are relatively frequent in Darevskia, although no direct evidence of recent gene flow has been previously documented. Our results further suggest that parthenogens are losing heterozygosity as a result of allelic conversion, hence their fitness is expected to decline over time as genetic diversity declines. Backcrosses with the parental species could be a rescue mechanism which might prevent this decline, and therefore increase the persistance of unisexual forms.

New records and geographic distribution of the sympatric zones of unisexual and bisexual rock lizards of the genus Darevskia in Armenia and adjacent territories

Caucasian rock lizards of the genus is a unique taxa, including both bisexual and parthenogenetic species. The parthenogenetic species have originated as a result of natural hybridisation between females and males of different bisexual species. The species involved in interspecific hybridisation are called parental. However, sympatric zones (SZ) of unisexual and bisexual rock lizards of the Caucasus are still poorly studied, although they are very important for understanding the role of hybrid individuals of different origin in reticulate evolution. This paper presents the location of the SZs of parthenogenetic and their parental bisexual rock lizards of the genus Darevskia in Armenia and adjacent territories of Georgia and Nagorno-Karabakh. We summarised the locations of the SZs identified from 1957 to the present, based on our field survey data gathered in 2018-2019 and records from publications and museum collections. This dataset includes 39 SZs of three types: SZ of parental bisexual species, SZ of parental species with unisexual species and SZ of the parthenogenetic species. For each zone, species composition, geographical and altitudinal distribution are presented. New records expand our knowledge of the geographical and altitudinal distribution of SZs in these species and provide additional data for understanding the mechanisms of reticulate evolution and hybridogeneous speciation in the past, present and future. The new records, including geographical and altitudinal distributions of three types of SZs, are presented, which expand the previously-known list to 39 locations of contact zones for parthenogenetic and its bisexual parental species of rock lizards of the genus Darevskia in Armenia and the adjacent territories of Georgia and Nagorno-Karabakh.

Parthenogenesis in weevils of the tribe Naupactini (Coleoptera, Curculionidae): a Wolbachia-density dependent trait?

The intracellular bacteria Wolbachia pipientis can manipulate host reproduction to enhance their vertical transmission. It has been reported an association between parthenogenesis and Wolbachia infection in weevils from the tribe Naupactini. A curing experiment suggested that a threshold density of Wolbachia is required for parthenogenesis to occur. The aim of this study was to analyze Wolbachia infection status in the bisexual species Naupactus xanthographus and Naupactus dissimulator.Wolbachia infection was detected in both species from some geographic locations, not being fixed. In all positive cases, faint PCR bands were observed. Quantification through real time PCR confirmed that Wolbachia loads in bisexual species were significantly lower than in parthenogenetic ones; this strengthens the hypothesis of a threshold level. Strain typing showed that both species carry wNau1, the most frequent in parthenogenetic Naupactini weevils. These infections seem to be recently acquired by horizontal transfer. Wolbachia was located throughout the whole body, which reinforce the idea of recent transmission. Moreover, we demonstrated that this strain carries the WO phage.Finally, the analysis of eubacterial 16S rRNA gene showed intense PCR bands for both bisexual species, suggesting –the presence of additional bacteria. Interspecific competition might explain why the parthenogenetic phenotype is not triggered.

An overview on the nomenclatural and phylogenetic problems of native Asian brine shrimps of the genus Artemia Leach, 1819 (Crustacea, Anostraca)

The genus Artemia Leach, 1819 is a cosmopolitan halophilic crustacean, consisting of bisexual species and obligate parthenogenetic populations. Asia is rich in Artemia biodiversity. More than 530 Artemia sites have been recorded from this area and more than 20 species/subspecies/variety names have been used for them. There exist various problems in the nomenclature, identification, and phylogenetic status of Artemia native to Asia, which are discussed in this paper.

Description of two new species of the genus Cacopsylla Ossiannilsson, 1970 (Hemiptera, Psylloidea) from northern Fennoscandia recognized by morphology, cytogenetic characters and COI barcode sequence

Based on chromosomal, molecular and morphological analyses, two new Cacopsylla Ossiannilsson, 1970 species are described, C. lapponica S. Nokkala &amp; Ch. Nokkala, sp. nov. and C. borealis S. Nokkala et Ch. Nokkala, sp. nov. (Hemiptera, Psylloidea). C. lapponica is a rare bisexual alpine species living on Vaccinium uliginosum Linnaeus, 1753 above tree line on northern hills, where it forms sympatric populations with C. myrtilli W. Wagner, 1947. So far, the species has been found in northern Finland, Utsjoki and Kilpisjärvi, and in northern Sweden, Abisko. The chromosome number in males is 2n = 12+X(0), characteristic of psyllids. The species is easily distinguished from C. myrtilli by its conspicuously smaller size mainly due to difference in wing size. Additional morphological differences are found in the length of antennae, female genital plates and male parameres. C. borealis, in turn, is a relatively common apomictic parthenogenetic species with 5n = 60 + XXXXX living on the same host plant, Ledum palustre Linnaeus, 1753, as C. ledi (Flor, 1861) and occasionally forming sympatric populations with it. No males have been recorded in C. borealis. Its distribution range reaches at least from northern Fennoscandia to Lake Baikal in the East. C. borealis can be distinguished from C. ledi by differences in the length and width of antennae, dark brown markings on the wing and female terminal structures. For molecular analysis, a 638 bp fragment of the mitochondrial COI gene was sequenced. C. lapponica differs from the cohabitating C. myrtilli by 20 fixed nucleotide substitutions (uncor rected p-distance 3.13 %), while C. borealis differs from C. ledi by 21 fixed nucleotide substitutions (uncorrected p-distance 3.29 %). Molecular phylogeny construction (ML and BI) reveals two highly divergent clades, one comprising two bisexual species, C. lapponica and C. fraudatrix Labina &amp; Kuznetsova, 2012, and the other clade comprising the parthenogenetic species C. borealis, C. myrtilli, and C. ledi. Within this clade, C. borealis is more closely associated with C. myrtilli than with C. ledi.

Ottelia fengshanensis, a new bisexual species of Ottelia (Hydrocharitaceae) from southwestern China

Ottelia fengshanensis, a new species (Hydrocharitaceae) from southwest China is here described and illustrated. Comparing its morphological features to putative close relatives O. guanyangensis, it has 3–4 flowers (vs. 2–5) each spathe, hexagonal-cylindric fruit, white styles (vs. yellow), green leaves (vs. dark green) and fruit tiny winged (vs. winged obviously). Molecular phylogenetic investigation of four DNA sequences (ITS, rbcL, trnK5’ intron and trnS-trnG) and the Poisson Tree Processes model for species delimitation (PTP) analysis, further resolves O. fengshanensis as a new species that is close to O. guanyangensis with distinct support.

New records of Darevskia armeniaca (Méhely, 1909) and Darevskia valentini (Boettger, 1892) (Squamata, Sauria, Lacertidae) from Armenia and updated geographic distribution maps

During field survey in 2018, we recorded in Armenia the occurrences of the parthenogenetic lizard Darevskia armeniaca and its “paternal” bisexual species D. valentini. Based on our new data and records taken from publications and museums, we update the distribution maps of these species. The new records expand the geographical boundaries of sympatric habitats of these species and provide additional data for understanding the mechanisms of reticulate evolution and hybrid speciation.