473 research outputs found
Description of a New Brown Frog from Tsushima Island, Japan (Anura: Ranidae: Rana)
Because all available evidence from allozymes, mtDNA sequences, and artificial hybridization suggests presence of high genetic differentiation between populations of East Asian brown frogs currently assigned to Rana dybowskii Günther, 1876, I compared morphological characters between specimens from Tsushima Island of Japan and Maritime territory of Russia. The population from Tsushima is slightly, but significantly different from R. dybowskii from Russia, including the holotype. I therefore consider the Tsushima population to be specifically distinct, and describe it as a new species R. uenoi. The new species also occurs in the Korean Peninsula and adjacent islands, but the distributional relationships with R. dybowskii are unclear, as detailed distribution in northern Korea is lacking
Age determination by skeletochronology of the Japanese salamander Hynobius kimurae (Amphibia, Urodela)
We investigated lines of arrested growth (LAG) of long bone tissues in a total of 157 salamanders of Hynobius kimurae from Tokyo and Kyoto, Japan. The number of LAGs did not differ between femurs, humeri, and toe phalanges. We found that the first LAG is formed after the first overwintering. The number of LAGs varied from 5-14 ((x) over bar=8.8) in reproductive males and 7-12 ((x) over bar=9.4) in mature females in the Tokyo population, while in the Kyoto population, males and females had 6-20 ((x) over bar=9.1) and 7-17 ((x) over bar=9.9) LAGs, respectively. This suggests that the minimum maturation age in males is five yr in Tokyo and six yr in Kyoto, while females of both populations need at least seven yr. The female-larger sexual size dimorphism, recognized in each population of this species seems to be attributable to a greater growth rate in females after the age of male maturity. Body size growth was better in Kyoto than in Tokyo, with average adult SVL being 3.2-3.6 times and 2.2-2.3 times of SVL of metamorphs, respectively. Adults of the Kyoto population, like metamorphs, are smaller than those of the Tokyo population, and such a difference is considered to be derived not from the differential age at maturity or growth rate but from the size difference at metamorphosis. In both populations, clutch size does not correlate to female age, but older and hence larger females tended to lay larger eggs. This suggests that the female fitness increases with age, not through an increase in the number of offspring per clutch, but through an elevation of survivorship per offspring
Karyotype of a Ranid Frog, Platymantis pelewensis, from Belau, Micronesia, with Comments on Its Systematic Implications
The karyotype of Platymantis pelewensis Peters, 1867, the only
native, endemic amphibian in Belau, extremely isolated from other congeners,
consisted of 2n = 22 homologous chromosomes largely forming a graded series.
Of these, chromosomes of pairs 1, 5, 6, 8, 10, and 11 were metacentric; the remainder
were submetacentric. Secondary constrictions were evident on shorter
arms of pair 7. This karyotype is nearly identical with that of P. papuensis
Meyer from New Guinea, but is distinct from two Philippine congeners hitherto
karyotyped both in chromosome number and morphology. This suggests that
the ancestral form of P. pelewensis dispersed from New Guinea or other Melanesian
islands
PHYLOGENETIC RELATIONSHIPS OF LEPTOBRACHIUM HASSELTII TSCHUDI, 1838 (AMPHIBIA, ANURA, MEGOPHRYIDAE) - DETECTION OF A POSSIBLE CRYPTIC SPECIES
By examining mitochondrial DNA phylogeny using 2424bp of sequence data 12S rRNA, tRNAval, and 16S rRNA genes, we evaluated the taxonomic relationships among Javan litter frogs Leptobrachium hasseltii from southern Sumatra, Java, and Bali. Leptobrachium hasseltii formed a well-supported monophyletic group, which comprised two major clades. One major clade represented the southern Sumatran and Javan populations and the other consisted of the population from Bali. The Javan and southern Sumatran clade included two subclades: the West Javan-southern Sumatran group and the Central Javan group. The genetic divergence between the two major clades (Bali vs. Java-Sumatra) suggested their separation happen at species level. Further studies using morphological and acoustic data are needed to determine the taxonomic status of Bali population
A New Salamander of the Genus Onychodactylus from Tsukuba Mountains, Eastern Honshu, Japan (Amphibia, Caudata, Hynobiidae)
Recent phylogenetic studies using mtDNA and allozymes have revealed the presence of large genetic differentiation within a Japanese clawed salamander, Onychodactylus japonicus, suggesting the presence of several cryptic taxa in this species. Based on morphological analyses, we describe one of them from the Tsukuba Mountains of Ibaraki Prefecture, in the Kanto district of eastern Honshu, as a new species, Onychodactylus tsukubaensis. It is a member of the japonicus species complex of Onychodactylus, and differs from the other species of the complex by a relatively short tail, wide head, and large number of vomerine teeth
Acoustic Characteristics of Treefrogs from Sichuan, China, with Comments on Systematic Relationship of Polypedates and Rhacophorus (Anura, Rhacophoridae)
Advertisement call characteristics of Polypedates chenfui, P. dugritei, and P. omeimontis, all from Sichuan, China, are described. Calls of the three species differ considerably from each other both in temporal and frequency patterns. Acoustically, these three species cannot be differentiated from some Rhacophorus species from Japan and Taiwan, and the systematic relationship of Polypedates and Rhacophorus needs reassessment
Morphological Variation in a Japanese Salamander, Hynobius kimurae (Amphibia, Caudata)
We studied variation in morphometric and meristic characters and color pattern in the salamander Hynobius kimurae, examining 282 males from 24 localities encompassing the whole distributional range of the species in Honshu, the mainland of Japan. Multivariate analyses of 24 morphometric characters resulted in the separation of two groups, (1) eastern populations from the Kanto District to Shizuoka Prefecture of the Chubu District, and (2) central-western populations from Aichi Prefecture of the Chubu District westwards. Similar groups were recognized in meristic characters and color pattern. These geographic patterns of morphological variation coincided with the pattern of genetic differentiation inferred from allozymes in this species, except for the position of one population from the intermediate region. Some of the morphometric and meristic characters significantly correlated with environmental parameters of sampling sites, and suggested effects of differential habitat conditions among populations on the geographic morphological variation in this species
Two Types of Hynobius naevius from the Central Region of Kyushu Island, Japan (Caudata: Hynobiidae)
We surveyed allozymic variation among Hynobius naevius from 11 localities of central Kyushu, Japan. The results revealed the presence of two genetic groups (I and II) that exhibited a great difference in allelic frequency and a large genetic distance. Specimens from seven of the 11 localities invariably belonged to Group I, and those from three other localities belonged to Group II. In the remaining one locality, representatives of both of these two groups were found just as in northern Kyushu. The two genetic groups also differed in morphological (Group I larger than Group II in body size) and ecological characters (breeding sites located in open streams in Group I, but possibly in underground water in Group II). These differences might have been enabling them to coexist
Morphometric Variation Analyses and Revision of the Japanese Toads (Genus Bufo, Bufonidae)
Two problems have been involved in the classification of the Japanese toads: (1) relationships with the continental forms, and (2) relationships among forms hitherto described within the islands. The present study was undertaken with the purpose of resolving the latter problem, and to achieve this, morphometric variation analyses were made of a large number of preserved specimens. The results were synthesized with the hitherto accumulated nonmetrical and non-morphological information so as to taxonomically revise the Japanese toads. A historical review of the classification of the Japanese toads revealed that the most complex problems were involved in the still-water breeding forms from the main islands (=the Japanese common toad), and that the taxonomic confusion was caused mainly by previous authors' classification through examination of a small number of specimens notwithstanding the great variability of external morphometric characters of the toads. The critical points for measurements for each character, and problems with measurement errors due to variant fixation and preservation are discussed. Allomorphic relations of 30 characters to SVL were analyzed for four age/sex groups of 147 Japanese common toads from Momoyama, Kyoto, with the result that many characters should be treated separately for three groups, i.c., young, adult males, and adult females. Besides, it was determined that simple ratios to SVL should not be calculated for many characters. For the Japanese common toad, SVL and relative value (ACV=theoretical value calculated by the allomorphic relationship of each character to SVL) of 10 selected characters for each of 2, 525 specimens belonging to 96 populations were analyzed, and the presence or absence of intrapopulational age and sexual variations and of interpopulational variations was noted. From these analyses, the Japanese common toad was divided into northeastern (A) and southwestern (B) types chiefly by the relative size of the tympanum diameter. For the two types of the Japanese common toad, presence of morphometric clines in relation to geographical and/or climatological parameters was investigated. Clear clinal tendencies were found mostly in type A, whereas few clear trends were detected in type B. Taxonomical meaning of the clines was discussed, and it was suggested that the Japanese common toad should be split into taxa below the species level. Similar morphometric analyses were made on the still-water breeding Miyako toad from the Ryukyu Archipelago. The results for 176 specimens from 4 populations indicated that this form was very uniform in external morphometry, that it greatly differed from the Japanese common toad in several characters, and that the differences were greater between this form and geographically adjacent type B Japanese common toads in some characters. Similar analyses were also performed on 265 specimens of 13 populations of the stream-breeding Japanese stream toad. Interpopulation variation in this form was very small. Comparisons with sympatric and allopatric populations of the Japanese common toad were made with the result that the two forms were found to be morphometrically almost completely separated, showing greatest differentiation in the zone of sympatry. Taxonomic conclusions were drawn with these results in mind. For the Japanese common toad, the type series or topotypes of each of the hitherto described forms were compared with the other populations and it was determined that neither type A nor type B can be split further. The syntypes of Bufo vulgaris japonicus, which is the oldest of all the described forms from Japan and is now kept in Leiden, were examined and a lectotype was designated and described. This form clearly belonged to type B. The nature of the intergradation of morphometric variations between type A and type B is discussed, and special attention is paid to the sudden change in the morphocline in the tympanum diameter. From this discussion, the relation of the two types is regarded as subspecific, and they are treated as B. japonicus formosus (type A) and B. j. japonicus (type B). For the Miyako toad, the morphometric difference from the Japanese common toad in the adjacent distribution range was studied, and the two forms are regarded as belonging to the different lineages. In addition, the known results of artificial hybridization support this idea, and therefore, the form is regarded as specifically different from japonicus and is treated as a subspecies (miyakonis) of the northeastern Chinese species B. gargarizans. The Japanese stream toad has been shown to have strong genetic compatibility with the Japanese common toad. Therefore, from the viewpoint of evolutionary taxonomy, the taxonomic value of the evidence from genetical sources is discussed. The two forms are distributed sympatrically, but are judged to seldom interbreed or show morphological intergradation in nature. Thus, notwithstanding the strong genetic compatibility of the artificial hybrids, the Japanese stream toad is regarded as a full species, B. torrenticola, as was originally described. In conclusion, the Japanese toads are taxonomically divided into three species, Bufo japonicus (j. japonicus Schlegel, 1838 and j. formosus Boulenger, 1883), B. gargarizans miyakonis Okada, 1931, and B. torrenticola M. Matsui, 1976
Total occlusion and string sign of radial artery versus saphenous vein graft conduits: An updated meta-analysis
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