The forest green tree frog, Zhangixalus arboreus, is a Rhacophorid species naturally distributed in Honshu and Sado Islands from Japan. This species is also known to have been introduced to the Izu-Oshima Island. In this study, we examined the feeding habits of Z. arboreus in Izu-Oshima Island because the knowledge of its foraging strategies may contribute to addressing conservation efforts on the island. We observed that frog stomachs contained 65 animal prey items, exclusively arthropods belonging to classes Arachnida, Insecta, and Diplopoda. The frog stomachs contained terrestrial and arboreal arthropods, suggesting that Z. arboreus feeds in a variety of habitats. We also found a large number of ants in frog stomachs. Our results differ from a previous study carried out on native populations of this species, which may be indicative of habitat differences among populations.

Snakes of the natricid genus Trachischium Günther, 1858 are distributed in the southern Himalayas. Due to their secretive nature and fossorial habits, their taxonomy, evolution, and ecology remain poorly understood. Based on a multilocus molecular phylogeny and morphological comparisons we explored Trachischium systematics. Results indicated that all representatives of Trachischium form a strongly supported clade with their close relatives in Blythia, and that Blythia is nested within Trachischium. Therefore, we suggest that Blythia is synonymous with Trachischium. Molecular data and morphological comparisons revealed cryptic diversity within Trachischium, and thus we describe one new species from China while also excluding T. guentheri and T. tenuiceps from the Chinese fauna.

The nuchal glands are organs of chemical defense embedded under the skin of several species of Rhabdophis and contain toxins sequestered from consumed prey. Rhabdophis subminiatus possesses nuchal glands, but not much information is available on its toxin source and prey preference, particularly based on its chemosensory response. We hypothesized that the response of R. subminiatus toward toads would be higher than other potential prey because the snake needs to sequester toxins contained in toad skin. We also examined the snake preference toward several bufonid species to test a hypothesis that the preference toward Duttaphrynus melanostictus is higher than other toad species due to its high availability in the habitat of the snake. To test the hypotheses, we conducted chemical response tests and compared the tongue-flick attack score (TFAS) of the snake toward prey chemical stimuli. The first experiment used only one toad species (D. melanostictus) and various potential prey animals for the source of chemical stimuli. The second experiment used chemical stimuli from several species of frogs and toads. In the first experiment, snakes showed the highest response toward D. melanostictus. However, in the second experiment, snakes showed the highest response toward a toad, Ingerophrynus biporcatus, followed by D. melanostictus, and a lower response toward another toad, Phrynoidis asper. These results indicate that the snake has a high preference toward toads, but its preference varies among toad species. Taken together, this study suggests that R. subminiatus discriminates different potential prey chemical cues and probably consumes toads to sequester their toxins.

We investigated the food composition of the Southeast Asian Rhacophorid frog species Polypedates leucomystax, an invasive species introduced to Okinawajima in the Ryukyu Archipelago, during their breeding activities and the month immediately after that. We examined the stomach contents of 190 males and 54 females, uncovering 215 prey items (including at least 56 species) from 113 males and 21 females. The rate of empty stomachs was relatively high, 45.1% for all frogs (40.5% for males and 61.1% for females). Most prey were arboreal, with a minority being obligately terrestrial or aquatic. Insects constituted the majority of the diet (61.4%), followed by other arthropods, gastropods, and a vertebrate (an agamid lizard neonate). Orthopterans were the dominant prey group in terms of number (29.8%), frequency of occurrence (43.3%), and volume (51.6%). This species is considered an opportunistic feeder, a conclusion corroborated by comparisons with locally varied dietary data from populations of conspecific or closely related species in Southeast Asia. The average prey length was approximately one-third of the body length, but instances of the consumption of larger prey were observed. Similarly, males are able to swallow prey up to two-thirds of their gape width and females up to one-third. The data obtained in this study cover most of the active season of this species on the island, and thus provide a basis for elucidating the ecological impact of this species.

The American bullfrog Lithobates catesbeianus is a well-known invasive alien species recorded in over 40 countries and islands. It is necessary to elucidate their seasonal emergence and habitat water body characteristics for implementing efficient eradication activities. Sado Island, Japan, is home to several endemic and rare species, including the endangered Sado wrinkled frogs (Glandirana susurra) that are concerned to be negatively impacted by invasive American bullfrogs. Here, we surveyed 41 ponds for invasive American bullfrogs over the period preceding emergence to the start of oviposition to determine their seasonal emergence and habitat pond use. As in previous studies, we observed initiations of their post-hibernation activities such as emergence, mating call, and oviposition in that order as air temperature increased, and those activities were thought to begin as late as late-April, mid-May, and mid-July, respectively on Sado Island. For their habitat preferences, we confirmed that they mainly inhabit relatively deep ponds surrounded by rice paddy fields. Our results were broadly consistent with those of previous studies, with respect to the seasonal emergence and habitat pond characteristics of American bullfrogs on Sado Island. Since our results suggest an overlap in habitat and pond usage season between American bullfrogs and Sado wrinkled frogs, we highly recommend implementing bullfrog eradication activities to conserve the Sado wrinkled frog population. This study provided the basic ecological information for selecting appropriate seasons and ponds for implementing bullfrog eradication activities.

Seasonal activity of the Japanese red-bellied newt, Cynops pyrrhogaster, was monitored in Minami-ohsawa, Hachioji-shi, Tokyo, from 2016 to 2017. The number of newts in the water of a pond was counted immediately after sunset, at least once a week, except in winter. The number of newts counted varied daily, and the time-series data on newt activity were analyzed using state-space modeling to estimate the impact of weather conditions and lunar phase on the activity due to the presence of plausible temporal autocorrelation. We found that some weather conditions, such as water temperature and atmospheric pressure, had significant positive effects on newt activity. Newts became more active during nights with higher temperatures and/or higher pressure. However, we did not detect any significant effect of the lunar phase on newt activity. The most important variable affecting newt activity was water temperature. The active season of newts was estimated to be nine months from March to November. Newt activity showed a sharp decline in the nightly activity of males and an extreme female-biased sex ratio was observed in early April suggesting that the degree of nocturnality differed across seasons and the two genders. This phenomenon may be related to the presence of mating activity during this particular season.

We present the first data on the life history traits and growth patterns of Boana riojana from 35 individuals belonging to two populations in central Argentina. We determined age using skeletochronology and analyzed morphometric variables in relation to these ages. The mean snout-vent length of sexually mature males was 53.7 mm, with an average age of 2.4 years. The species had a maximum longevity of four years, and the minimum age at sexual maturity was two years, which was consistent across both populations. Body size and age showed a positive correlation. The von Bertalanffy growth equation revealed an asymptotic snout-vent length of 59.7 mm and a growth coefficient of 0.87. Additionally, a decline in growth rate was observed from the second to the third year of age. We found no significant differences in the variables between both populations. In conclusion, determining the individual age of different populations of B. riojana has, for the first time, allowed us to establish the life history traits of the species.

Zooarchaeological studies of vertebrate remains from four lowland archaeological sites (consisting of 24 features) in the Kinki District, Honshu, have led to the reconstruction of certain components of local amphibian assemblages that existed in the past, ranging from a few centuries Before Common Era to the Eighth Century Common Era. However, the Japanese Rice Frog, Fejervarya kawamurai, a presently common and obligate lowland species with several biogeographic peculiarities, has been consistently absent from these reconstructions. The data presented here suggests that the major lowlands of this district (the Osaka and Wakayama plains and the Nara Basin) were devoid of this species until later times, and that the invasion was facilitated by human activities. This finding also supports a long-neglected view that the populations of this species in mainland Japan originated from an introduction.

Goniurosaurus k. kuroiwae consists of two genetically diverged entities (i.e., northern and southern lineages) that are geographically separated by a narrow hybrid zone in the north–central part of Okinawajima Island, Ryukyu Archipelago, Japan. Our molecular analyses using single nucleotide polymorphism data confirmed their remarkable genetic differentiation. Morphological comparisons using random forest models further revealed that these two lineages could be distinguished by combinations of several characteristics. Considering that these two entities have persisted within a single island, they deserve to be given full species status. The type locality of the nominal species, G. kuroiwae, fell within the range of the “southern species” and the morphological features of the holotype agreed well with the “southern species”. Hence we described the populations of the northern part of Okinawajima and Kourijima as a new species, Goniurosaurus nebulozonatus sp. nov. This new species differs from other congeners in the Ryukyus with a combination of the following character states: reddish brown iris, 4–7 postmentals, flat and imbricate ventral scales, denser tubercles on the femur, single most-enlarged scale on the pes base, mid-dorsal stripe present at the nape and absent in the posterior part of the trunk, incomplete or no nuchal loop, dorsal band on the posterior trunk present, and obscure dorsal stripes/bands. The new species was inferred to be a sister taxon of G. kuroiwae sensu stricto, so allocating other taxa as subspecies of G. kuroiwae no longer makes sense. Thus, we propose elevating all five taxa currently regarded as subspecies of G. kuroiwae to full species, G. orientalis, G. sengokui, G. toyamai, G. yamashinae, and G. yunnu. Adding G. splendens in Tokunoshima and the two species in Okinawajima, there are now seven extant and one extinct species exist in the Ryukyu Goniurosaurus.

Northern Andes Mountains exhibit high elevational fluctuation in thermal conditions for ectotherms. This fluctuating temperature limits the survival, growth, and dispersion of ectothermic organisms. Therefore, lizard species distributed on these mountain landscapes face strong temperature fluctuations. To test the potential effect of elevation, we characterized the critical maximum (CT_max) and minimum (CT_min) body temperature and time to reach CT_max (T_max) and CT_min (T_min) of individuals of Anolis tolimensis, an endemic species distributed on two cordilleras in the northern Andean system in Colombia. We collected individuals at four elevations (1,600, 1,900, 2,100, and 2,200 m asl) and measured their critical thermal limits under laboratory conditions. We also explored the role of sex and size on these physiological thermal variables. CT_max is similar among the elevations, but CT_min of the highest elevation (2,200 m asl) is the lowest (5.5±1.0°C) vs (2,100 m asl, 8.8±0.8°C; 1,900 m asl, 8.3±1°C; 1,600 m asl, 8.3±0.9°C). CT_max range is narrower (33–34.2°C) than CT_min (5.5–8.8°C), and thermal tolerance breadth (CT_min to CT_max values) is 28.7°C. Sex and body size may affect the thermal response, but the interaction varies with geography. Critical thermal limits are conservative (CT_max) or evolutionary labile (CT_min). Anolis tolimensis could deal with maximum environmental temperatures by thermoregulatory behavior or by an alternative strategy of increasing the time to reach the CT_max. Finally, extinction risk evaluation is needed to test the potential vulnerability of the population at the second-highest elevation.

Climate change may cause a decrease the habitat and population of organisms and has a direct impact on biodiversity. In particular, ectotherms such as amphibians are more vulnerable to changes in environmental factors than other taxa. In this study, we identified the main distribution areas and habitat characteristics of three Brown Frog species inhabiting South Korea based on observation points and species distribution modeling techniques, and predicted distribution changes under climate change models. Altitude, temperature, diurnal range, and precipitation were identified as environmental variables having a major influence, and the distribution showed a different form depending on the surroundings of the Taebaek Mountains Range. As such, the spatial distribution ranges and habitat characteristics predicted by the species distribution model reflected the results of previous studies. Analyses of distributions under predicted future climates found suitable areas for Rana uenoi are expected to increase by 6% in RCP4.5 and decrease by 67% in RCP8.5 compared to the current distribution range. Likewise, areas suitable for R. huanrenensis decreased by 86% in RCP4.5 and 99% in RCP8.5, and for R. coreana decrease by 95% in RCP4.5 and 99% in RCP8.5. Overall, it was found that suitable habitats are rapidly decreasing due to climate change. These results suggest the possibility that climate change could seriously affect amphibians. Additional research into the main microenvironmental factors that affect species decline will help prepare management plans for vulnerable species.