太田 英利

A molecular phylogenetic survey was conducted using mtDNA sequences of 12S and 16S rRNA, and cyt-b genes to examine taxonomic relationships among populations of the Pan-Oriental microhylid, Microhyla ornata, from India, Bangladesh, Thailand, Laos, China, Taiwan, and the Ryukyu Archipelago of Japan. Two discrete clades are recognized within this species, one consisting of populations from India and Bangladesh, and the other encompassing the remaining populations. In the latter clade, populations from the Ryukyu Archipelago are clearly split from the rest (populations from Taiwan and the continent) with considerable degrees of genetic differentiations. Each of the three lineages is judged to represent a good species, and the name Microhyla ornata is restricted to the South Asian populations. For the populations from Taiwan and a wide region from China to Southeast Asia, the name Microhyla fissipes should be applied, whereas the Ryukyu populations are most appropriately referred to as Microhyla okinavensis, although further substantial genetic differentiations are recognized among some island group populations within this last species.

A large gravid female of Hydrophis melanocephalus was captured in early December 2004 from offshore of Wakayama Prefecture, west-central Honshu, Japan. This is the first confirmed record of this species from waters adjacent to Honshu. The female gave birth to three juveniles (one born alive, and the other two stillborn) within three days of capture. Autopsy of the female after her death in one month later yielded another developing embryo and four undeveloped eggs in oviducts. This suggests that her actual litter size was four and potential litter size was eight. © 2005, The Herpetological Society of Japan. All rights reserved.

Gehyra veriegata ogasawarasimae was described in 1930 from Chichijima Island of the Ogasawara Group, Japan, and then was reported to have 2n=63 chromosomes in 1949. Subsequently this taxon was synonymized with Lepidodactylus lugubris, a parthenogenetic species complex consisting of a number of diploid-triploid clones distributed in tropical Pacific and Indian Ocean islands. The above chromosome number, as well as dorsal color pattern of an individual illustrated in a figure of its original description, suggests that the type of G. v. ogasawarasimae (lost) belonged to a triploid clone of L. lugubris. However, all L. lugubris recently collected from Chichijima Island and another island of the Ogasawara Group had only 2n=44 chromosomes and belonged to a diploid clone, so-called clone A. A survey of museum specimens of L. lugubris collected from Chichijima Island during 1960-1970s yielded three specimens showing dorsal pattern characteristic of a triploid clone, so-called clone C. These suggest that the triploid clone C previously occurred on Chichijima Island and was erroneously described as Gehyra variegata ogasawarasimae. This clone may have been displaced by the diploid clone A through inter-clonal competition after recent colonization of the latter to Chichijima and other Ogasawara islands. © 2005, The Herpetological Society of Japan. All rights reserved.

The Kikuzato's brook snake, Opisthotropis kikuzatoi, is a highly endangered aquatic or semiaquatic species endemic to Kumejima Island of the Okinawa Group, Ryukyu Archipelago. Field studies were carried out for some ecological aspects of this species by visiting its habitat almost every month from April 1996 to March 1997. The results demonstrate that the snake is active almost throughout the year. It is also suggested that the snake tends to be diurnal in the warmer season, and nocturnal in the cooler season. Observations on a case of autonomous emergence onto the land, very slow growth, and predation on small crabs, are also provided.

A field survey was carried out for a population of Eumeces elegans on Kita-kojima Island of the Senkaku Group, Ryukyu Archipelago. Data for several reproductive parameters, such as clutch size, egg size, hatchling size, and hatching date, are provided for the first time for the Japanese populations of this species. Variations in midbody scale rows and hatchling coloration between the Senkaku populations and the Taiwanese and continental populations are clarified and their geohistorical significance is discussed briefly. © 2004, The Herpetological Society of Japan. All rights reserved.

Insectivorous lizards usually employ one of two foraging modes, ambush 'sit-and-wait' or active 'widely foraging', but in the Gekkonomorpha the situation has been unclear. Therefore we quantified the foraging mode of the eublepharid gecko Goniurosaurus kuroiwae orientalis on Tokashikijima near Okinawajima, Japan, in September 1999. The taxon is rare, endangered and protected. On the selected semi-urban study site the gecko was confirmed as a nocturnal cursorial gecko, which also ascends trees up to 1.8 m. Foraging regimes of marked individuals, during repeated 30-min observation periods, could vary from immobility throughout, to active locomotion 84% of the time. Foraging mode was not significantly affected by sex, body length, mass or state of tail regeneration of the individuals, or by the timing of the observation. In males, at higher temperatures single moves became longer, while time allocated to moving was stable. In both sexes longer observation bouts included longer sitting pauses, which, given stable move duration, reduced the share of time spent moving and the moves per minute. Goniurosaurus kuroiwae orientalis averaged moving during 23% of the time, moving 0.39 times per minute, the moves lasting 77 s and the pauses lasting 745 s. Compared to other geckos, G. k. orientalis may be defined as a widely foraging animal, despite its mixed behaviour. This result supports the definition of the Eublepharidae as widely foraging and is compatible with two hypotheses, that early Gekkonomorpha were widely foraging or that they had an intermediate, undefined, foraging mode.

Phylogenetic relationships of the three lygosomine skink genera occurring both in the Old World and the New World (Mabuya, Scincella and Sphenomorphus) were inferred from mitochondrial DNA sequence of 12S and 16S rRNA genes. Results strongly suggested the non-monophyly for any of these three genera. Within the Mabuya group, Asian members appear to have diverged first, leaving the Neotropical and the Afro-Malagasy Mabuya as sister groups. These relationships, together with the absence of extant or fossil representatives of the Mabuya group from North America, strongly suggest the trans-Atlantic dispersals of Mabuya from Africa to Neotropics. Our results also indicated a closer affinity of the New World Scincella with the New World Sphenomorphus than with the Old World Scincella. Such relationships suggest the trans-Beringian dispersal of the common ancestor from Asia and its subsequent divergence into the North American Scincella and the Neotropical Sphenomorphus.<br>

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 mark and recapture study was carried out for three years on a population of the Ijima's sea snake, Emydocephalus ijimae, in the coastal shallow water of Zamamijima Island, central Ryukyus, Japan. The relatively high recapture (47% of 167 marked snakes) suggests that E. ijimae is a particularly philopatric, sedentary species among the sea snakes. The sex ratio (male: female), approximately 1.6:1, significantly skewed from 1:1. The growth rate in SVL declined with growth, with females thoroughly growing better than males. Males and females were estimated to begin reproductive activity in the second or third summer and the third spring after birth, respectively. Frequency of female reproduction is guessed to vary from annual to biennial, or even less frequent.

The population of the lygosomine genus Tropidophorus on Sulawesi, Indonesia, is usually referred to as T. grayi Günther, 1861, a species originally described from the Philippines, or sometimes by a taxonomically unjustified epithet "apulus". We therefore reexamined the taxonomic status of the Sulawesi Tropidophorus on the basis of newly obtained specimens and available museum materials. Results indicated that this island population is morphologically distinct from T. grayi, and we thus describe it as a new species. This species most resembles T. grayi by sharing a number of characteristics, such as a divided frontonasal, three preanals, and strongly keeled tail scales. However, it differs from the latter by having weaker keels on dorsal body scales, a relatively longer fourth toe with more subdigitals, and male postanal pores in a single row. © 2003, The Herpetological Society of Japan. All rights reserved.

Japalura polygonata, occurring in the East Asian islands, is currently divided into three subspecies-J. p. polygonata from the Amami and Okinawa Groups of the central Ryukyus, J. p. ishigakiensis from the Miyako and Yaeyama Groups of the southern Ryukyus, and J. p. xanthostoma from northern Taiwan. A new subspecies is described for this species from Yonagunijima Island of the Yaeyama Group. This subspecies differs from other conspecific subspecies in having distinctly enlarged and irregularly arranged scales on the dorsolateral surface of the body. In other subspecies, the degree of enlargement of such scales is smaller, and they usually form somewhat regular rows in a transverse direction on the flanks, and in a longitudinal direction in the paravertebral region. Males of the present subspecies differ from those of other subspecies in having a series of large white spots against a dark grayish tan on the dorsolateral surface of the body, whereas the females are characterized by brilliant green dorsal coloration. © 2003, The Herpetological Society of Japan. All rights reserved.

Developmental changes in external morphological characters were examined for the whole embryonic-larval period of Microhyla ornata from Okinawajima Island, Ryukyu Archipelago, Japan. By considering the extent of morphological changes observed and compatibility with standard developmental tables hitherto proposed for other anuran groups, a developmental table consisting of 45 developmental stages was proposed for this species. Eight developmental terms, each consisting of several successive stages, were also defined-Cleavage-Blastula [stages 1-10], Gastrula [stages 11-14], Neurula [stages 15-18], Tail bud [stages 19-21], External gill [stages 22-28], Hind limb bud [stages 29-33], Hind limb formation [stages 34-41], and Metamorphosis [stages 42-45]). From previously described conspecific samples from other localities, our sample exhibited appreciable differences in the egg diameter, timing of pigmentaion at the position of the stomodium, and a few other tadpole characters. © 2003, The Herpetological Society of Japan. All rights reserved.

Phylogenetic relationships of the freshwater turtles of the genus Mauremys and representatives of several other batagurid genera were inferred from variations in 863 base positions of mitochondrial 12S and 16S rRNA genes. Results strongly suggested the non-monophyly of Mauremys by indicating the closest affinity of Mauremys japonica with Chinemys reevesii, the type species of the genus Chinemys. Recent morphological analyses of the batagurid genera suggested that Mauremys is a basal stock of the subfamily Geoemydinae, whereas Chinemys is a member of the subfamily Batagurinae as supported by several putative synapomorphs with other batagurine genera. It is thus probable that the morphological character states used to define Mauremys actually represent symplesiomorphy, and that morphological character states shared between Chinemys and other batagurine genera have resulted from convergence. Also, our results did not support a sister-group relationship between Mauremys annamensis and Mauremys mutica , which has been implicitly or explicitly assumed by a number of previous authors on the basis of morphological data. Instead, M. annamensis was indicated to be closest to Mauremys versoni, a species assumed to be most divergent among the East Asian Mauremys by previous authors.

Phylogenetic relationships of the genus Cuora sensu lato (Cuora sensu stricto and Cistoclemmys) and other testudinoid genera were inferred from variations in 882 base positions of mitochondrial 12S and 16S rRNA genes. Results yielded a robust support to the monophyly of a group (Cuora group) consisting of Cuora sensu lato and the monotypic Pyxidea. Within the Cuora group, the continental Cuora (sensu stricto) and the two subspecies of Ci. flavomarginata constituted two well-supported monophyletic groups. Distinctly small interspecific genetic distances in the former groups suggested that in the continent speciations in Cuora took place much later than the primary divergences in the Cuora group, or speciations in other related genera, such as Mauremys. Our analyses failed to provide a substantial support to the monophyly of any other combinations of taxa within the Cuora group, including Cuora in broad and strict senses, and Cistoclemmys as consisting of Ci. galbinifrons and Ci. flavomarginata. Besides these, our results also suggested the non-monophyly for the Batagurinae and the Geoemydinae, and sister relationships of the Bataguridae with Testudinidae rather than with the Emydidae.

Historical relationships were inferred for the oriental lizards of the genus Takydromus Daudin 1802 (Lacertidae) on the basis of DNA sequences. Of the 17 species currently recognized for the genus, 13 species represented by 42 specimens from 29 localities were examined. Maximum-likelihood and maximum-parsimony analyses of data for 829 aligned sites from parts of the mitochondrial 12S and 16S rRNA genes yielded relationships that, while showing no substantial discrepancy with each other, were strikingly different from a currently prevailing phylogenetic hypothesis from a parsimony analysis of morphological characters. Based on the results of these molecular analyses, supplemented by results of the morphological analysis that offered robust evidence for positions of two additional species (T. khasiensis and T. sylvaticus), the following interrelationships were hypothesized as the most preferred phylogeny: (kuehnei (sexlineatus khasiensis))(tachydromoides ((smaragdinus (sauteri (dorsalis sylvaticus))) (amurensis (((formosanus wolteri) hsuehshanensis)(toyamai (septentrionalis stejnegeri)))))). These interrelationships indicate: (1) invalidity of Platyplacopus Boulenger 1917, which was recently resurrected as a subgenus of Takydromus on the basis of the morphological analysis; (2) homoplasy in states of some morphological characters, such as green dorsal coloration, that were considered as synapomorphs of certain nodes in the morphological analysis; and (3) involvement of the genus in a series of vicariances in both the continental and insular parts of eastern Eurasia. Due to the paucity of available samples, phylogenetic status of T intermedius and T. haughtonianus remain to be examined in future studies. (C) 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 76,493-509.

Three new species of the genus Tropidophorus, characterized by distinct depression of body, strongly keeled lateral body scales, and saxicolous habits, are described from Indochina. Of these, two moderately depressed species, one with undivided frontonasal and widened paravertebral scales, and the other with divided frontonasal and unwidened paravertebral scales, were collected from small areas in northeastern and eastern Thailand, respectively. The remaining species with extremely depressed head and body was found from one limited area in northern Vietnam. The three species most resemble T. baviensis Bourret, 1939 from northern Vietnam among the known congeneric species in body size, body shape, and scutellation. However, body depression in T. baviensis is not so prominent as in the present three species. Considering that most specimens of these species were collected from rock crevices, their characteristic body shapes may represent certain stages of adaptation to life in crevices.

We karyotyped four lizards, Acanthosaura armata, Bronchocela cristatella, Calotes emma, and C. versicolor, all belonging to the tropical Asian clade of the family Agamidae. The karyotype of A. armata consisted of 12 metacentric macrochromosomes and 20 microchromosomes, whereas B. cristatella had 14 metacentric macrochromosomes and 20 microchromosomes. Except for the presence of 22 microchromosomes, the karyotypes of the two Calotes species were similar to that of A. armata. The 20 microchromosome state in the A. armata karyotype may have emerged in the ancestral lineage common to Gonocephalus robinsonii, whose karyotype also exhibits a 12M + 20m format. Comparison of the present results with previously published information suggests the presence of cryptic taxonomic diversity in B. cristatella and C. versicolor. © 2002, The Herpetological Society of Japan. All rights reserved.

The genus-group name Babina, originally proposed as a full genus for Rana holsti (type species) and R. subaspera, is usually attributed to "Van Denburgh, 1912". However, it is obvious from the chronological order of publication of relevant papers that the authorship of Babina should be "Thompson, 1912", not "Van Denburgh, 1912". © 2002, The Herpetological Society of Japan. All rights reserved.

The Oriental large-bodied crested dragons of the genus Gonocephalus are known to include two distinct karyomorphs. To evaluate their phylogenetic significances, we conducted phylogenetic analyses of the genus together with other agamid genera on the basis of 862 base positions of mitochondrial 12S and 16S rRNA genes. Results suggested the presence of two distinct lineages within Gonocephalus, of which one, represented by G. robinsonii that has a 2n=32 karyotype, was closer to other Oriental agamid genera than to the other congeneric lineage. Monophyly of the latter, characterized by unique chromosomal arrangement among agamid genera (2n=42 karyotype), was confirmed. It is thus likely that states of morphological characters shared between the two lineages are derived through convergence, or represent symplesiomorphy. Our results also suggest that the karyological similarity between G. robinsonii and several Australian agamids, pointed out in a previous study, is actually attributable to homoplasy rather than their recent common ancestry.

We assessed the validity of two gekkonid species, Gekko yakuensis and G. hokouensis, in southern Japan. We first assigned ah 398 specimens into 18 samples merely on the basis of localities. By conducting significance test for deviations of genotype frequencies from Hardy-Weinberg at II 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-Fl 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 F, 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. (C) 2001 The Linnean Society of London.

Scincella boettgeri and S. formosensis are two small lygosomine skinks endemic to the southern Ryukyus and Taiwan, respectively. Taxonomic separation of these two species depends on only a few external characters that are seemingly more or less variable within each species. To investigate the geographic pattern of their morphological variations, multivariate analyses were performed for 23 meristic and 16 morphometric characters in 680 specimens of S. boettgeri from 12 islands of the Miyako and Yaeyama Groups and 193 specimens of S. formosensis from ten localities in Taiwan. The canonical discriminant analysis (CDA) for samples representing local populations using meristic data completely separated the southern Ryukyu and Taiwanese assemblages, supporting their assignments to different taxa. On the other hand, the analyses using morphometric data remained their variations partially overlapping each other. Of the samples of S. boettgeri examined, the Haterumajima sample markedly varied from the others, whereas the Kaohsiung sample was somewhat divergent among the S. formosensis samples. Neighbor-joining phenograms derived from Mahalanobis distances among the samples showed branching patterns apparently inconsistent with the topographical (for S. formosensis) or putative geohistorical relationships of their localities (for S. boettgeri). This suggests that in these species external quantitative characters often rapidly vary under the influence of localized environments rather than of the passage of time after geographical isolations.

The male and female karyotypes were examined for 10 specimens of the Chinese soft-shelled turtle, Pelodiscus sinensis, from the main islands of Japan and Taiwan by the bone marrow air-dry technique. One specimen of Dogania subplana was also examined karyologically. Although both P. sinensis and D. subplana had 2n=66 chromosomes, they showed an interspecific variation in chromosome morphology. No karyotypical differences were evident between the Japanese and Taiwanese samples of P. sinensis, or within either of them. Comparisons of the present results with previously reported trionychine karyotypes indicate that there are some interspecific and intraspecific variations in centromeric positions of several macrochromosome pairs in this subfamily. © 2001, The Herpetological Society of Japan. All rights reserved.

An electrophoretic survey of samples of the gekkonid lizard, Gekko hokouensis, from the East Asian islands demonstrated that two genetically divergent, but morphologically almost identical, entities occur on five islands of the Okinawa Group, Ryukyu Archipelago, Japan. These entities, while sharing all of the external character states diagnostic of G. hokouensis, exhibited fixed allele differences at six to eight out of 30 loci examined and great overall genetic distances [Nei&apos;s (1978) D = 0.489-0.654]. On Kumejima and Tonakijima Islands of the Okinawa Group, the two entities were collected together from identical microhabitats. These results indicate that the two entities represent separate biological species. Genetic comparisons of these two cryptic species from the Okinawa Group with &apos;G. hokouensis&apos; from other island groups revealed that one occurs broadly in the insular region of East Asia, whereas the other is restricted to the Okinawa Group. Implications of the present findings for the morphological evolution of &apos;G. hokouensis&apos; are also discussed.

Lepidodactylus lombocensis and Lepidodactylus intermedius, both from the Lesser Sunda Archipelago, Indonesia, are usually considered synonyms or subspecies of the broadly distributed Lepidodactylus lugubris. However, reexamination of the type specimens of these taxa revealed that they are actually distinct from L. lugubris in having characteristics of Brown and Parker's (1977) Group II, such as undivided terminal scansors on all digits and subcylindrical tails without distinct lateral edges or serrations. The two species also differ from other Group II species in several meristic characters. Furthermore, L. lombocensis and L. intermedius differ from each other in a few characters, such as the number of scale rows at midbody and dorsal color pattern. We thus consider both of these species as valid. A revised key is provided to the Group II species of Lepidodactylus.

The mourning gecko, Lepidodactylus lugubris, is an all-female parthenogenetic species widely distributed in tropical and subtropical regions. We examined clonal diversity of L.. lugubris in southern Japan, the northernmost extremity of the species' range. Results indicated that the assemblages of the Ogasawara Islands are composed solely of diploid clone A, which may have originated from artificial transportation after World War II. Assemblages of L. lugubris in the Ryukyu Archipelago were composed solely of triploid clone C. This, along with literature records, suggests that the gecko recently colonized the Ryukyu Archipelago on limited opportunities from limited sources. Samples from the Daito Islands included both diploid and triploid individuals representing one and 11 different clones, respectively. Except for one triploid clone (clone B), these clones were most likely to be endemic to the Daito Islands. Analyses of genotypic pattern suggest that most of the putative endemic triploid clones of the Daito Islands originated from iterative crosses between sympatric diploid clones and males of closely related bisexual species that were most likely extirpated subsequently.

Phylogenetic relationships among the lygosomine skinks were inferred from 1249 base positions of mitochondrial DNA sequences of 12S and 16S rRNA genes. The monophyly of this subfamily was confirmed and the presence of five distinct infrasubfamilial lineages detected. Of these, the Sphenomorphus group appears to have diverged first, followed by the Lygosoma and Egernia groups in order, leaving the Eugongylus and Mabuyra groups as sister groups. Our results did not support monophyly of the Mabuya group sensu late (i.e., an assemblage of the Lygosoma, Egernia, and Mabuya groups), for which a number of morphological and karyological studies demonstrated a considerable similarity. Our results also contradict the previous hypothesis, formulated on the basis of morphological and immunological data, which argued for the sister relationship between the Egernia and the Eugongylus groups. Morphological and karyological characters used to define the Mabuya group (sensu lato) may actually represent plesiomorphic states. The phylogenetic diversity of lygosomine skinks in the Australian region appears to have increased through multiple colonizations from Southeast Asia. (C) 2000 Academic Press.