Using the lines of arrested growth (LAGs), we estimated the age structure of a breeding population and individual ages at sexual maturity of a salamander, Hynobius lichenatus, from Sendai, northeastern Japan. No significant sexual differences were detected in either the age structure or the age at maturity, and the breeding individuals ranged from 5 to 14 yrs old, while the age of their maturation ranged from 3 to 7 yrs old. Reasons for this difference in minimal ages remain to be studied. There was no significant correlation between the age and the body size of the salamanders. Hynobius lichenatus does not differ from its close relative H. tokyoensis from Tokyo in age structure, but mature significantly later, with a longer life, than H. tokyoensis from Chiba. These findings suggest that the age structure of these salamander populations is affected at most partially by temperature conditions, and more strongly by other environmental, ecological, or phylogenetic factors.

Two new species of the salamandrid genus Pachytriton are described from Anlui and Guangxi, China, based on molecular and morphological analyses. One of them from Huangshan, Anhui, has smaller body, longer limbs, and larger eye than the remaining congeners. The other from northeastern Guangxi possesses a larger body and head, and longer snout and tooth series than the remaining congeners. Also, we have found that two individuals of Pachytriton obtained from pet shops in Japan can represent an unnamed species, but do not describe them as new because we have no exact information on their original localities. The distribution patterns and ecological relationships among species of Pachytriton are discussed.

Field surveys were made for geographic distributions of two geckos, Gekko hokouensis and G. yakuensis, within Yakushima, a mountainous island located in southwest of Kyushu, mainland Japan. Gekko yakuensis was found from an almost entire lowland area encompassing various environments, whereas G. hokouensis was restricted to four villages and their vicinity. In many other villages G. hokouensis was not found at all, although G. yakuensis occurred. The four villages having G. hokouensis populations are characterized by ports that have or once had regular vessel sails from other islands of the northern Ryukyus or southern Kyushu where this species is common. Our results strongly suggest that the current Yakushima populations of G. hokouensis have originated from multiple accidental artificial introductions from outside and that G. yakuensis is the only native gekkonid of the island. In this study, we also found hybrids of G. hokouensis and G. yakuensis from a few localities on Yakushima Island. This suggests that genetic introgression may be in progress from the former to the latter species on this island.

Ovophis okinavensis is an endemic pitviper of the subtropical region of Japan. Based on information from various localities, the species has been considered a dietary generalist that exploits various terrestrial vertebrates. We analyzed stomach contents of O. okinavensis in a northern mountain area on Okinawa Island, based on data of a 10-years-study, to examine its trophic features at the population level. We recovered a total of 461 prey items, which were comprised of six, three, five, and three species of frogs, reptiles, birds, and mammals, respectively. Approximately 93% of dietary items consisted of frogs, the majority of which belonged to two explosively breeding species aggregating to restricted spots along the stream only during their reproductive season (winter). On the other hand, from April to November, the snake mainly depended on vertebrates other than frogs. Neither an ontogenetic dietary shift nor intersexual dietary divergence was evident although males tended to exploit one of the two explosively breeding frog species more frequently than females. There were weak positive correlations between snake size and prey size, but large snakes did not drop small prey items from their diet. Average body mass of each prey item was only 5.2% of snake body mass. Characteristics of trophic features of O. okinavensis of this population, such as extremely high dependency on frogs in winter, the absence of ontogenetic dietary shift, and utilization of small sized prey, are discussed in comparison with other viperids.

We investigated sex ratio in seven populations of the Japanese pond turtle, Mauremys japonica, inhabiting ponds in the central region of Aichi Prefecture, Japan. The sex ratio, calculated as a numerical proportion (%) of males to total individuals sexed, was highly variable among the populations, ranging from no more than 20.0% to no less than 92.9%. Since M. japonica shows a temperature-dependent sex determination (TSD) with eggs producing more males under a relatively low incubation temperature and more females under a higher temperature, we hypothesized that the observed remarkable inter-population variation in sex ratio reflects that in the nest temperature. Our field observations indicated that the nesting sites of male-biased populations were largely shaded by wood, thus supposedly under a relatively low ambient temperature, while those of female-biased populations were located in open environments with direct exposure to solar heat. These results offer a circumstantial support to the above hypothesis. Remarkably skewed sex ratios observed in some populations might reflect the effect of substantial habitat fragmentation and severe nesting site limitation caused by recent artificial land development and changes in agricultural land use. If this is actually the case and the effect continues to operate, many of the M. japonica populations may eventually disappear.

We measured the straight carapace length (SCL) of 1392 loggerhead turtles of the Japanese aggregation that were incidentally captured between July 2002 and November 2009 by pound nets set near the eastern coast of Cape Muroto, Kochi Prefecture, Japan. Each specimen was categorized as adult, subadult, or juvenile on the basis of their maturity status inferred from SCL. In the present sample, SCL exhibited a unimodal distribution with the mode located in the 740––749 mm class ( ±±SD: 757±±67 mm; range: 563––1050 mm). The majority of loggerhead turtles composing the Japanese aggregation was subadult (75.9%). The SCL of smaller specimens suggested that reentery into Japanese waters of individuals once flown to the northeastern Pacific occurs in the later juvenile stage. A unimodal histogram implies that the major size classes in SCL of turtles reentering Japanese waters range from 560––749 mm. A comparison between the Japanese aggregation and the Mexican aggregation indicates that turtles at the later juvenile stage start to migrate westward, taking only a few years to cross the North Pacific to Japanese waters.

The published work making available the nomen Leptobrachium nokrekensis Mathew and Sen, ““2009”” 2010, bearing a date of publication of 2009, is shown to have been published on 3 June 2010. The taxon is further shown to be a member of the genus Leptolalax Dubois, 1983. Leptolalax nokrekensis (Mathew and Sen, 2010) is compared with the three known congeners from India (L. khasiorum, L. lateralis, and L. tamdil). A table of comparative data for all recognized species of Leptolalax is presented.

A field survey was made in 2006 for the exotic black-spotted pond frogs Rana nigromaculata in central Hokkaido, northern Japan. The result suggested a prominent range expansion of this frog since the previous survey in 1997. Examinations of stomach contents from 140 frogs yielded 662 prey items that almost entirely consisted of invertebrate preys, such as lepidopteran larvae, water striders (Gerridae), and spiders (Araneae). The result suggests a fairly little impact, if any, of this accidentally introduced frog upon the native tree frog Hyla jponica through direct predation.

We studied the reproductive cycle of the introduced gecko, Phelsuma laticauda from a histological analysis of museum specimens from Hawaii. All adult males >40 mm SVL exhibited spermiogenesis in samples collected in January to April and in August. Females invariably produced clutches that contained two eggs. The presence of oviductal eggs and concomitant yolk deposition in some of the same females as well as the presence in the population of juveniles during both summer and winter months, indicate P. laticauda produces multiple clutches in Hawaii. The smallest reproductively active female (early yolk deposition) measured 46 mm SVL. Considering the potential negative effects on endemic Pacific island lizards, colonization by P. laticauda should be discouraged.