Contrasting patterns of genetic variation in the two sympatric geckos Gekko tawaensis and G. japonicus (Reptilia: Squamata) from western Japan,as revealed by allozyme analyses

Allozyme variation in two congeneric sympatric geckos, Gekko tawaensis and G. japonicus, from western Japan was examined. These species show similar densities and spatial arrangements of populations in this region, and their genetic structures are thus expected to have been formed under the influences of comparable geohistorical, environmental, and demographic factors. Results of the analyses, however, revealed strikingly different genetic patterns in the two species. Populations of G. tawaensis invariably showed a remarkably lowered heterozygosity (0-0.017) compared to G. japonicus (0.089-0.124). On the other hand, the genetic heterogeneity among populations is much greater in G. tawaensis (F(ST)=0.726) than in G. japonicus (F(ST)=0.101). The Mantel test failed to detect any significant correlations between log (estimated migration rate) and log (geographic distance) in either species, or between matrices of interpopulation pairwise F(ST) for the two species. These results suggest that, in each species, formation of the current genetic structure in western Japan has been chiefly influenced by stochastic factors, rather than the geohistorical architecture of this region. The high F(ST) and low heterozygosity in G. tawaensis suggest the effects of severe local fragmentation. On the other hand, the relatively low F(ST) and high heterozygosity in G. japonicus imply extensive gene flow among populations. Absence of significant correlations between the estimated migration rate and geographic distance in G. japonicus may suggest that such gene flow is promoted by human-mediated transport of this primarily house-dwelling lizard.     

A New Species of the Gekko japonicus Group(Squamata: Gekkonidae) from Southwest China

A new species of the Gekko(Squa ma ta:Gekkonidae)is described from the border of Sichuan and Yunnan Province,southwest China,based on distinct morphological and molecular features.Gekko jinjiangensis sp.nov.is distinguished from congeners by a combination of the following characters:size small(SVL 50.2–61.6 mm,n=13);nares in contact with rostral;interorbital scales between anterior corners of the eyes 20–24;ventral scales between mental and cloacal slit 146–169;midbody scale rows 111–149;ventral scale rows 31–47;subdigital lamellae on first toe 8–11,on fourth toe 11–15;no webbing in the fingers and toes;with tubercles on uapper surface of fore and hind limbs;precloacal pores 4–5 in males;postcloacal unilateral tubercles 1–2;dorsal surface of body with 8–9 large greyish brown markings between nape and sacrum.In molecular analyses,the new species is sister to G.scabridus,but separated from them by approximately 9.9%–12.2%in genetic divergence as shown by a fragment of the partial mitochondrial ND2 gene.The new species is the highest Gekko with elevation range from 2000 to 2476 m.Further surveys are recommended to better understand the occurrence and population status of the new species.     

Karyotype Reorganization in the Hokou Gecko (Gekko hokouensis,Gekkonidae): The Process of Microchromosome Disappearance in Gekkota

The Hokou gecko (Gekko hokouensis: Gekkonidae, Gekkota, Squamata) has the chromosome number 2n = 38, with no microchromosomes. For molecular cytogenetic characterization of the gekkotan karyotype, we constructed a cytogenetic map for G. hokouensis, which retains the ancestral karyotype of Gekkota, with 86 functional genes, and compared it with cytogenetic maps for four Toxicofera species that have many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) and that for a lacertid species (Lacerta agilis) with only one pair of autosomal microchromosomes. Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG). However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis. These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes.     

Mitochondrial Diversity and Phylogeographic Patterns of Gekko gecko(Squamata: Gekkonidae) in Thailand

The Tokay Gecko, Gekko gecko(Linnaeus, 1758) is widely distributed in Asia and there have been concerns regarding locally decreasing populations due to overexploitation for traditional Chinese medicine. Previous studies of the genetic relationships of G. gecko populations included few populations from Thailand. Here we investigated the phylogeographic patterns of G. gecko from different regions in Thailand using mitochondrial cytochrome b sequences. Phylogenetic analyses revealed two lineages: one(Lineage A) comprising populations from Laos, Vietnam, and Thailand; and a second(Lineage B) comprising three genetically distinct groups within Thailand alone. Some Thai populations were found to have both lineages represented within them. Highly significant genetic differentiation(FST) showed geographic population structuring in Lineage B, indicating limited gene flow among groups in Thailand. Although G. gecko has a wide distribution and is well adapted to human habitation, the observed genetic structure could potentially be explained by geographic barriers such as mountain ranges. In Lineage A, our study provided primary phylogeographic evidence for lineage mixture that might be a result of human-mediated transport. Future research should include more extensive sampling across the geographic distribution of G. gecko and a landscape genetics approach could be applied for conservation planning.     

The development of cephalic armor in the tokay gecko (Squamata: Gekkonidae: Gekko gecko)

Armored skin resulting from the presence of bony dermal structures, osteoderms, is an exceptional phenotype in gekkotans (geckos and flap-footed lizards) only known to occur in three genera: Geckolepis, Gekko, and Tarentola. The Tokay gecko (Gekko gecko LINNAEUS 1758) is among the best-studied geckos due to its large size and wide range of occurrence, and although cranial dermal bone development has previously been investigated, details of osteoderm development along a size gradient remain less well-known. Likewise, a comparative survey of additional species within the broader Gekko clade to determine the uniqueness of this trait has not yet been completed. Here, we studied a large sample of gekkotans (38 spp.), including 18 specimens of G. gecko, using X-rays and high-resolution computed tomography for visualizing and quantifying the dermal armor in situ. Results from this survey confirm the presence of osteoderms in a second species within this genus, Gekko reevesii GRAY 1831, which exhibits discordance in timing and pattern of osteoderm development when compared with its sister taxon, G. gecko. We discuss the developmental sequence of osteoderms in these two species and explore in detail the formation and functionality of these enigmatic dermal ossifications. Finally, we conducted a comparative analysis of endolymphatic sacs in a wide array of gekkotans to explore previous ideas regarding the role of osteoderms as calcium reservoirs. We found that G. gecko and other gecko species with osteoderms have highly enlarged endolymphatic sacs relative to their body size, when compared to species without osteoderms, which implies that these membranous structures might fulfill a major role of calcium storage even in species with osteoderms.     

Gas exchange morphometry of the lungs of the tokay,Gekko gecko L. (Reptilia: Squamata: Gekkonidae)

The tokay lizard (Gekko gecko) possesses singlechambered lungs, eacch of which is a mirror image of the other reflected in the midsagittal body plane. When standard techniques are employed for instilling 2% phosphate-buffered glutaraldehyde to three-quarters of the total lung capacity, neither the left nor the right lung is consistently larger. Internally, the lungs are characterized by a row of 11 dorsomedial niches and by honeycomb-like (faveolar) gas exchange tissue, which is deeper cranially than caudally. Based upon mean values for all experimental animals, a 100-g tokay would have an overall anatomical diffusion factor (respiratory surface area divided by the appropriate _ht) of 203 cm²·m^-1·100 g^-1, 61% of which is located on the interfaveolar septa. Of the total septal anatomical diffusion factor, 94% is evenly divided between the anterior and middle thirds of the lung, with 6% in the posterior third. The 39% of the anatomical diffusion factor located on the inner lung wall is predominantly (76%) in the middle and posterior lung thirds, with only 24% in the anterior region. These tendencies toward heterogeneous distribution of anatomical diffusion factor were most pronounced in a 55 g juvenile animal. In this animal the total anatomical diffusion faxtor/body mass was 3.6 times that of a 197 g adult. This difference was attributable to a greater body massspecific lung volume and respiratory surface area as well as to a greater surface-to-volume ratio in the parenchyma and to a thinner air-blood diffusion barrier in the juvenile animal.Abbreviations ADF anatomical diffusion factor - %AR percentage of potential respiratory surface area which makes up S_AR - DtO₂ diffusing capacity for air-blood tissue barrier - IUR isotropic uniform randomly distributed - bm body mass - %P percentage of lung volume devoted to parenchyma - S _A potential respiratory surface area (S _L minus the surface area of the trabeculae) - S _ANR non-respiratory surface area - S _AR respiratory surface area - S _L total internal surface area of the lung - S _v surface area-to-volume ratio in parenchyma - _ht harmonic mean thickness of the air-blood tissue barrier - V _L morphometrically determined volume of both lungs, fixed at 0.75· V _Lm - V _Lm maximal lung volume, similar to total lung capacity in mammals - V _Lr resting lung volume, similar to functional residual capacity in mammals - VP morphometrically determined volume of parenchyma of both lungs, fixed at three-quarters of V_Lm     

Genetic Structure of the Red-spotted Tokay Gecko,Gekko gecko(Linnaeus, 1758)(Squamata: Gekkonidae) from Mainland Southeast Asia

This study was performed to explore the genetic diversity and genetic structure of red-spotted tokay geckos(Gekko gecko) from 23 different geographical areas in Thailand, Lao PDR and Cambodia. The mitochondrial tRNAGln/tRNA-Met/partial NADH dehydrogenase subunit 2 from 166 specimens was amplified and sequenced. A total of 54 different haplotypes were found. Highly significant genetic differences occurred between populations from different localities. The haplotype network revealed six major haplogroups(G1 to G6) belonging to different clades(clade A–E). Clade D and clade E were newly observed in this study. Haplogroup G4(clade D) was a sympatric population with haplogroup G1(clade B). The populations from northern Thailand were divided into two distinct haplogroups separated by mountain range. Genetic structure and genetic differentiation of the tokay in Southeast Asia was related to the geographical region sampled, spatial distance and natural barriers. Our results indicate that red-spotted tokay geckos from mainland Southeast Asia are cryptically diverse. Morphological comparisons, in addition to an intensive genetic investigation covering the whole species range, are needed to clarify the systematic and population structure of this species group.     

A new species of Thecadactylus from Sint Maarten, Lesser Antilles (Reptilia, Squamata, Gekkonidae)

We describe a new species of Thecadactylusfrom the Caribbean island of Sint Maarten. The new species differs from all other species in the genus by having a distinct dorsal pattern of numerous irregular but sharply deliminated black spots and blotches on an otherwise almost patternless background.     

Three species of rust fungi (Uredinales) from Okinawa,Japan

Three species of rust fungi were reported based on the specimens collected in the islands of the Yaeyama group and Okinawa, Japan.Puccinia tarennicola onTarenna gracilipes andUredo daphniphylli onDaphniphyllum teijsmannii were described as new species.Villebrunea frutescens was added to the host plants ofUredo pipturi. Contribution No. 115, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Molecular phylogenetic relationships among species of the Malagasy-Comoran gecko genus Paroedura (Squamata: Gekkonidae)

We use approximately 3100bp of mitochondrial (ND2, ND4) and nuclear (RAG1, phosducin) DNA sequence data to recover phylogenetic relationships among 14 of the 16 recognized taxa of the lizard genus Paroedura as well as two undescribed forms. These geckos are endemic to Madagascar and the Comores and are popularly kept and bred by herpetoculturalists. The closest relative of Paroedura is another Indian Ocean leaf-toed gecko, Ebenavia. Both Bayesian inference and maximum parsimony strongly support the monophyly of two major clades within Paroedura that conflict with existing species group assignments based on scale characteristics. Our well-resolved tree elucidates a biogeographic pattern in which eastern Paroedura are most basal and western and south-western species form a monophyletic group. Our data demonstrate the phylogenetic utility of phosducin, a novel marker in squamate phylogenetics, at the intrageneric level.     

Cryptic diversity within the Moroccan endemic day geckos Quedenfeldtia (Squamata: Gekkonidae): a multidisciplinary approach using genetic,morphological and ecological data

Quedenfeldtia (Boettger, 1883) is a genus of diurnal geckos, endemic to the Atlas Mountains in Morocco, with two species being recognized: Quedenfeldtia moerens and Quedenfeldtia trachyblepharus. Quedenfeldtia moerens is found across a wide variety of habitats, from sea level to 3000 m a.s.l., whereas Q. trachyblepharus occupies exclusively high mountain regions reaching up to 4000 m a.s.l. This differentiation, offers an interesting model for study biogeographical patterns and evolutionary scenarios in a North African endemic. Analysis of two mitochondrial (12S rRNA and ND4) and four nuclear (ACM4, MC1R, PDC, and Rag1) DNA markers revealed high genetic variation, consistent with other recent phylogeographical studies, and with the two currently described species. However, within each species, a subdivision into two groups with geographical consistence was found. Multivariate morphological analyses confirmed the existence of two main phenotypes, whereas ecological niche modelling identified various environmental variables associated with the distribution of each species, and helped to predict occurrences outside the confirmed ranges. The results obtained in the present study indicate the possible existence of additional ‘cryptic’ species within this genus, a condition found in many North African reptiles, and particularly common in geckos. In general, North African montane fauna appears to reflect the occurrence of diverse palaeoendemics, as seen in Central Africa Mountain systems, rather than the pattern of recent postglacial recolonization observed in Europe. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Biochemical assessment of evolution and taxonomy of the morphologically poorly diverged geckos, Gekko yakuensis and G. hokouensis (Reptilia: Squamata) in Japan, with special reference to their occasional hybridization

We assessed the validity of two gekkonid species, Gekko yakuensis and G. hokouensis, in southern Japan. We first assigned all 398 specimens into 18 samples merely on the basis of localities. By conducting significance test for deviations of genotype frequencies from Hardy‐Weinberg at 11 allozyme loci, we checked the reproductive unity of constituents in each of those local samples, and where necessary, rearranged them into subsamples on the basis of genetic markers so that we recognized minimum reproductively cohesive units. We then compared allele frequencies among all samples and subsamples examined. Results clearly indicated that all but two can be classified into two groups that can be discriminated from each other by remarkable allele frequency differences at four diagnostic loci, and by large genetic distances even between sympatric subsamples. Observations of morphological features of the samples and subsamples confirmed that the two groups correspond to G. yakuensis and G. hokouensis, supporting validities of these two species. Allele frequency comparisons, however, also revealed that the remaining two samples, both from southern Kyushu, possessed ‘marker alleles' of both G. yakuensis and G. hokouensis at all four diagnostic loci. These samples thus were considered to represent populations that have been derived through hybridization of the two species. Detailed analyses for genetic structures demonstrated that all hybrid genotypes in the two samples are post‐Fi generations with only one individual resulting from the back‐cross with a pure line population of G. yakuensis. This finding negates the possibility that the hybrid populations are maintained by a constant supply of newly produced Fj hybrids, but suggests that the hybrid genotypes constitute stable breeding populations. This implies that the genealogical independence of G. yakuensis and G. hokouensis in several other sympatric areas has been maintained by operations of some isolation mechanisms at a pre‐mating phase. Investigations of the morphological variation in each sample or subsample revealed that although the two species can be externally largely discriminated from each other by slight modifications of the currently used diagnoses, it is difficult to detect their hybrids based solely on the morphological features.     

Relationships within theRugopharynx delta species complex (Nematoda: Strongyloidea) from Australian marsupials inferred from allozyme electrophoretic data

Relationships between the strongyloid nematodesRugopharynx delta, R. zeta, R. omega, R. longibursaris, R. mawsonae andR. sigma, all from macropodid marsupials, were investigated using allozyme data. The phylogenetic trees derived from the electrophoretic data set were congruent with those of the hosts and were consistent with the hypothesis that the species complex originated in pademelons of the genusThylogale and diversified in rock-wallabies (Petrogale spp.) and scrub wallabies of the subgenusNotamacropus. Host switching is evident only between closely related macropodid taxa.     

Detection by allozyme electrophoresis of cryptic species of Hypodontus macropi (Nematoda: Strongyloidea) from macropodid marsupials.

Allozyme electrophoresis of 98 Hypodontus macropi from eight different species of hosts using 24 enzymes revealed a complex of at least six sibling species, with 15-50% fixed genetic differences between taxa. Except for the taxon parasitizing Macropus rufus/M. robustus, pairs of parasite taxa were, in each case, sympatric at each locality examined, thus supporting the conclusion that they represent valid species. The existence of a series of host-specific nematode taxa explains many of the inconsistencies noted previously in the host distribution of H. macropi. Comparison of parasite allozyme phenograms with host phylogeny suggests that four of the speciation events could be attributable to cospeciation and two to host switching. A clear case of host switching between M. rufus/M. robustus and M. fuliginosus was found.     

Recombination within sympatric cryptic species of the insect pathogenic fungus Metarhizium anisopliae

Metarhizium anisopliae is an insect pathogenic fungus with a worldwide distribution. It is being developed and used as a biocontrol agent against a wide range of insect pests but relatively little is known of the life history of this fungus. We tested hypotheses concerning reproductive isolation and recombination in a sample of heat-active (ability to grow at 37 degrees C) and cold-active (ability to grow at 8 degrees C) sympatrically occurring isolates of M. anisopliae from Ontario, Canada by assaying nucleotide sequence variation at six polymorphic loci: the internally transcribed spacer (ITS) region of the nuclear ribosomal DNA repeat, and portions of calmodulin (CAL), chitin synthase (CHS), subtilisin-like protease (PR1), neutral trehalase (NTL) and actin (ACT)-encoding genes. The most parsimonious trees constructed showed a topology consistent with the heat-active and cold-active isolates as two monophyletic groups. We then applied Genealogical Concordance Phylogenetic Species Recognition (GCPSR) to the genealogical trees and concluded that the transition from concordance among branches to incongruity among branches delimited two species of M. anisopliae within Ontario. The GCPSR of two species was supported by intraspecific incongruity within each species when tested using the Partition Homogeneity test, indicating recombination. The GCPSR of two species also corresponded to the heat-active and cold-active groups. As the groups are morphologically indistinguishable we applied the term 'cryptic species'. Therefore, the sympatrically occurring heat-active and cold-active isolates represent different cryptic species with a history of recombination among isolates within each species.     

Multiple cryptic species of sympatric generalists within the avian blood parasite Haemoproteus majoris

The avian haemosporidian parasite Haemoproteus majoris has been reported to infect a wide range of passerine birds throughout the Holarctic ecozone. Five cytochrome b (cyt b) lineages have been described as belonging to the morphological species H. majoris, and these form a tight phylogenetic cluster together with 13 undescribed lineages that differ from each other by < 1.2% in sequence divergence. Records in a database (MalAvi) that contains global findings of haemosporidian lineages generated by universal primers suggest that these lineages vary substantially in host distribution. We confirm this pattern in a data set collected at Lake Kvismaren, Sweden, where three of the generalist lineages have local transmission. However, whether these lineages represent intraspecific mitochondrial diversity or clusters of cryptic species has previously not been examined. In this study, we developed novel molecular markers to amplify the partial segments of four nuclear genes to determine the level of genetic diversity and gene phylogenies among the five morphologically described cyt b lineages of H. majoris. All five cyt b lineages were strongly associated with unique nuclear alleles at all four nuclear loci, indicating that each mitochondrial lineage represents a distinct biological species. Within lineages, there was no apparent association between nuclear alleles and host species, indicating that they form genetically unstructured populations across multiple host species.     

Karyotypic variation in the Australian Gekko Phyllodactylus marmoratus (Gray) (Gekkonidae: Reptilia)

The gekko Phyllodactylus marmoratus has at least three distinct chromosome races; 2n=36, 2n=36 ZZ/ZW and 2n=34. Specimens from these races are morphologically distinguishable, have a degree of habitat specialization and occur in a defined distribution. The 2n=36 race found in Eastern Australia is the presumed primordial type. The 2n=34 race occurs in Western Australia and is regarded as a fusion derivative. The 2n=36 ZZ/ZW race, which is only found on the Murray River system in Eastern Australia has a heteromorphic sex chromosome system present in the female. Giemsa banding suggests that this heteromorphism is the result of a pericentric inversion.