Two new species of the dwarf litter frog genus Leptobrachella are described from North and Central Kalimantan, Indonesian part of the Borneo Island. Leptobrachella fusca n. sp. from Bulungan Regency, differs from all congeneric species in the following combination of characters: body small (SVL: 16.3 mm in a male); dorsum uniformly dark brown; sides of body without marking; a series of elongate ventrolateral glands present on flank; ventrum darkly pigmented except for throat and posterior portion; lineae masculinae invisible through ventral skin in preservative; and toe webs rudimentary. Leptobrachella bondangensis n. sp. from Gunung (=Mt.) Bondang of Murung Raya Regency, is distinct in possessing the following combination of characters: body large as this genus (SVL: 17.8 mm in a male); dorsum grayish brown; sides of body without dark blotches; a sparse series of rounded ventrolateral glands present on flunk; ventrum pale gray with dark mottles; lineae masculinae invisible through ventral skin in preservative; and toe webs rudimentary.
The red-eared slider turtle, Trachemys scripta elegans, is an invasive species, that may potentially induce negative impacts on native turtle communities and freshwater ecosystems. Effective control of invasive species requires knowledge of the process of invasion and the long-term dynamics of an introduced population. However, such studies are scarce. We investigated temporal changes in the species composition of a freshwater turtle assemblage including density and age structure of the red-eared slider turtle at the Kahokugata lagoon of Ishikawa Prefecture in central Japan over 15 years (2001–2003, 2013 and 2015). The number of red-eared sliders increased over time, whereas that of Reeves’ pond turtle, Mauremys reevesii, remained flat for 15 years from 2001 to 2015. Data on morphological measurements in the red-eared slider population showed that the proportion of old individuals increased whereas juveniles decreased. Moreover, the body condition index decreased in all age classes. These results suggest that juvenile recruitment was limited in the recent years and thus breeding efficiency was lowered in the red-eared slider population at this lagoon perhaps due to high population density.
Thermal reaction norms of sprint speed were examined in three lacertid lizard species (Takydromus tachydromoides, T. smaragdinus, and T. dorsalis). We found inter- and intraspecific variations in maximum sprint speed, optimal body temperature, and thermal performance breadth for the best sprints. The thermal performance breadth of T. smaragdinus was broader than that of T. tachydromoides or T. dorsalis, whereas T. dorsalis sprinted faster than the others. In T. smaragdinus, individuals with narrower performance breadths run faster within their thermal range of expertise. There were “specialist” individuals of which performance depended heavily on high temperatures, as well as “generalist” individuals that performed well over a broad range of temperatures even within a single population. We discussed that the spatiotemporal instability of habitats might favor more than one type of thermal reaction norm of sprint performance, and this phenomenon may be driven by specialist–generalist trade-offs.
Lepidodactylus lugubris is an all-female parthenogenetic gecko. This gecko consists of diploid and triploid clones in the tropical and subtropical regions, and Clones A (diploid) and C (triploid) cohabit most islands in Ogasawara, Japan. On some Ogasawara islands, another cosmopolitan, but sexually reproductive, gecko Hemidactylus frenatus coexists with L. lugubris. This situation offers a unique opportunity to examine interactions not only between asexual female clones of L. lugubris but also between L. lugubris and both sexes of H. frenatus. We induced behavioral contests for food in small laboratory enclosures between two individuals of different clone, sex, and species combinations. Clone C interacted with other individuals less frequently and had a lower success in feeding the prey than Clone A and both sexes of H. frenatus. Clone C also showed few aggressive behaviors such as arches, growls, bites, and lunges, and never wrestled with other individuals. This interactive tendency of Clone C helps explain the microdistribution patterns of these sympatric geckos in the field.
Expansion of the habitat occupied by the hybrid giant salamander (Japanese×Chinese giant salamander, Andrias spp.) in the Kamo River of Kyoto Prefecture, Japan, has been a serious problem for the conservation of the Japanese giant salamander, A. japonicus. Thus, the movement and behavior of hybrid giant salamanders must be determined to quantify their ecological impact. Biotelemetry facilitates the long-term tracking of this species in rivers if transmitters are surgically implanted successfully. However, to use this approach successfully, it is important to understand the effects of surgical implantation and the healing process after surgery on animals. Nine hybrid salamanders were surgically implanted with dummy transmitters, while three individuals were incised without implanting any transmitters as the control treatment. Three months of observation after surgery showed that all individuals survived and retained transmitters. No hernia was observed in implanted individuals, and surgical incisions completely healed in one to two months. Body weight increased in all individuals, with no significant difference being observed in the weight gain and growth rate of implanted versus control individuals. The present study demonstrated the successful retention of implanted dummy transmitters in giant salamanders for three months without severe effects, suggesting the utility of biotelemetry for monitoring individuals in the wild.
The mourning gecko Lepidodactylus lugubris broadly occurs in the Indo-Pacific region and is also recorded from some parts of the insular and coastal Latin America. Despite its presence in a number of localities along coastal Southeast Asia, L. lugubris has not ever been reported from Thailand. We observed several individuals of this gecko on Bulon Le Island in 2012 and 2013, and on this island and Mook Island in 2017. This is the first record of L. lugubris in Thailand. In addition, we examined photographs of this species taken in Southeast Asia and deposited in iNaturalist.org (including ours from this study), and recognized two clones on the basis of dorsal color pattern: triploid clone C from Thailand, India (Andaman Islands), Indonesia, and Malaysia, and diploid clone A from Singapore.
Thermal biology of snakes has been extensively studied, but vast majority of them deals with diurnal species distributed in temperate regions. During a long-term field study of a pitviper on subtropical Okinawa Island, the Ryukyu Archipelago, Japan, we had an opportunity to obtain body temperature data from six syntopic species of snakes belonging to the families Colubridae, Xenodermidae, Viperidae, and Elapidae that are active at night there. Mean body temperature of those nocturnally active snakes over a year was relatively low, ranging from 17.7 to 22.3°C, although research effort was largely biased to the cooler period of the year. Lowest body temperature of the six species ranged from 10.9 to 20.0°C. Irrespective of species, body temperature was highly correlated with both ambient air and substrate temperatures. Importance of future research on the activity of subtropical, nocturnal snakes under low temperature is briefly discussed.
Nesting in tropical highlands is challenging due to the fluctuations of temperature, including extreme cold, and humidity. For most reptiles in the highland tropical region the thermal and hydrological profiles of nests have not been described, and it is therefore uncertain how future climate change may affect this ontogenetic stage. We monitored 17 communal nests of Anadia bogotensis at a highland locality in Colombia. The soil humidity and temperature of the nests and the air temperature were recorded for almost a year, together with other physical and biotic nest characteristics. Nests exhibited high temporal and spatial thermal variation unrelated to the nests’ physical characteristics. The maximum and minimum temperatures of the nests and air exhibited a linear and positive relationship, whereas the thermal variance (CV) exhibited a linear and positive relationship with maximum air temperature. Furthermore, CV of the heating phase was higher than that of the cooling phase for the nest and air temperature and it was similar between nests with and without viable eggs. However, it was different between each nest type and air temperature. During the cooling phase the average CV was different between nests with and without viable eggs and between nests and air temperature. In conclusion, the temperature of the nests exhibits strong daily fluctuation, and most of the nests follow the same fluctuation as air temperature. However, it seems that the rock covering some nests prevents the nest temperature from falling as quickly as the air temperature and from reaching the minimum environmental value.
Observations on stereotyped defensive behaviours are presented for 7 frog species of the Neotropical genus Odontophrynus from Argentina and Uruguay. Seven stereotyped postures were observed, among which the most common observed were puffing up the body, contracting, and crouching down. Newly reported behaviours include tongue protrusion, eye protection, and some combinations of postures. We provide an account of defensive behaviours already described in Odontophrynus and discuss the correspondence between the terminology used by previous authors and recently proposed classifications. In addition, we highlight defensive mechanisms associated with the body raising posture in Neotropical anurans, which may include intimidating predators, body shape disruption, warning signaling, and exposure of skin macroglands.
We bred black turtles (Chelonia agassizii) in captivity to improve our understanding of the reproductive biology of this species. One male and one female black turtle were maintained in a single outdoor tank with an open-water system at the Ocean Expo Park, Okinawa, Japan. Ultrasonographic observations indicated that the female (straight-line carapace length: 810 mm, body mass: 91.6 kg) first exhibited follicular development during March 2017. In May 2017, the male mounted the female for approximately 120 min, during which copulation occurred. The female later laid five clutches; the first eggs were released under water 32 days after mating, because of the absence of a suitable nesting substrate. After the female was transferred to another tank with an artificial beach, the second, third, and fifth clutches were laid on an artificial beach between July and August, but the fourth clutch was released underwater again. The mean (±standard deviation) internesting interval, clutch size, and egg diameter were 11.8±3.1 (range: 9–16) days, 45.2±13.8 (29–67) eggs, and 45.3±0.7 (44.0–47.0) mm, respectively. Hatchlings emerged from clutches 52–57 days after egg laying, with a total emergence success rate of 12.1% (14 hatchlings from 116 eggs). The straight-line carapace length and body mass of hatchlings were 48.8±2.0 (44.0–51.2) mm and 27.6±2.1 (24–30) g, respectively. This study is the first to report the breeding success of black turtles in captivity.