Helminthological examination was made on 42 individuals of Polypedates leucomystax captured on Miyakojima of the Miyako Group, Ryukyu Archipelago, Japan. Eight species (one digenean, five nematodes, one acanthocephalan, and one oligochaete) were recognized, of which one nematode Strongyloides sp. characterized by the presence of an isthmus in the esophagus, seemed to have been newly adopted by P. leucomystax from herpetofaunal elements native to Miyakojima. Meanwhile, Raillietnema rhacophori and Allodero sp. were considered to have reached this island by accompanying P. leucomystax from the Central Ryukyus. Present specimens of R. rhacophori differed from conspecific specimens from the Okinawa Group and Malaysia in a few morphological characters, presumably as a result of bottlenecks through the host’s dispersals involving a limited number of worms.
Phylogenetic relationships within the genus Leptolalax have been insufficiently resolved, while the relationships of a related genus Leptobrachella with other genera are totally unknown. In order to improve these situations, we assessed the phylogenetic relationships among 19 species of Leptolalax and four species of Leptobrachella based on 2067–2527 bp sequences of the mitochondrial 12S and 16S rRNA genes using maximum likelihood and Bayesian inference methods. Leptolalax and Leptobrachella formed a clade, in which each of the Bornean Leptolalax, continental Leptolalax, and Leptobrachella formed a clade with unresolved relationships. Within the continental clade, the species from the Malay Peninsula formed a sister clade to the clade of the remaining regions. The species from southern Thailand formed a sister clade to the species from more northern regions. These results suggest confining the name Leptolalax to Bornean species, and reexamining the contents of the name Lalos currently recognized. Pointed digital tips unique to Leptobrachella might have arisen parallelly in ancestral Leptolalax as in Leptobrachium. Absence of species common to both Borneo and the neighboring continent in Leptolalax unlike in many other anuran genera occurring in Borneo, suggests a unique evolutional history of the genus.
Nine male and eight female adult nematodes in the genus Kalicephalus reported from albino Japanese ratsnakes, Elaphe climacophora from Iwakuni City, Yamaguchi Prefecture, Japan, were re-examined to confirm their taxonomic placement. Previously, these nematodes were identified as K. natricis Yamaguti, 1935, despite the fact that the name had been regarded by some earlier authors as a species inquirenda. Our close re-examination of the morphological characters of both sexes suggests that those worms actually belong to K. sinensis Hsü, 1934, which has been recorded from several Japanese snakes, including E. climacophora.
Ecological information on inconspicuous, small, fossorial, and nocturnal snakes is very limited. We investigated seasonal activity patterns of Achalinus spinalis, a small, nocturnal, and fossorial snake endemic to East Asia. We also examined factors that affect its activity pattern above the ground. The seasonal activity of the snake showed a bimodal pattern, which peaked in early summer and autumn. Males were more active than females in early summer. Gravid females were captured in May and July, but we did not find any gravid females in June. Effect of temperature on the snake activity was found in autumn, and a positive relationship between snake activity and prey (earthworms) abundance was detected in early summer. The prey items were confirmed from eight snakes, and half of the diet records were obtained in June. The annual activity pattern of A. spinalis was concordant with that in other species of temperate snakes. However, the activity of juvenile snakes is considerably different from that of temperate snakes: hatchlings of A. spinalis remained underground and did not actively move after hatching until emergence from their first hibernation early the following summer.
We studied and documented the normal development of the tree-hole breeding frog Kurixalus eiffingeri from oocyte to completion of metamorphosis in the laboratory at a temperature of 25±2 C. We divided its development into 46 stages and then described and illustrated its external features at each stage. Uncleft eggs at the stage 1 of development were 2.10 mm (SD=0.14) in diameter. Most larvae hatched at the stage 25, usually by seven days after fertilization. Soon after hatching, tadpoles fed on unfertilized eggs that were supplied periodically by the parent female as observed in the field. Dorsally situated eyes, a frontally placed mouth, scarce teeth (dental formula 2/2), and a large stomach of this tadpole may be adaptive for eating trophic eggs that are generally soft and supplied periodically from the surface of water. By 43 days on the average, the tadpoles attained their maximum size, reaching stage 41 and 29.74 mm (SD=1.13) in total length, with a relatively long tail, which is also an adaptive trait for swimming to the water surface to eat the trophic eggs. During the subsequent tail absorption, the basal half of their forelegs became white and prominent against their dark grey bodies. After 53 days on the average, the tadpoles completed their metamorphosis into frogs, reaching their final 46th stage and 11.10 mm (SD=0.94) in snout to vent length.
Most lizards have well developed auditory abilities, while not actually vocalizing to any extent outside of geckos. However, except for geckos, function of hearing in lizards has not been well investigated. Recently, the ability to eavesdrop on the alarm calls of a syntopic avian species has been demonstrated in four species of lizards that belong to different families. This suggests that eavesdropping is a major function of hearing in lizards. To examine this possibility we tested the ability of heterospecific eavesdropping by a lizard that belongs to another family in an Ampijoroa forest of Madagascar, where two lizard species have been known to show this ability. We experimentally tested whether Zonosaurus laticaudatus, a gerrhosaurid lizard, has the ability to eavesdrop on the alarm calls of the Madagascar paradise flycatcher. In the experiment, we provided bait on the ground in front of free-ranging zonosaurs to induce their foraging activity and played back alarm calls or songs of the bird to them. The number of individuals that stopped foraging in response to the alarm calls was larger than that in response to the songs. Similarly, the number of individuals that fled in response to the alarm calls was larger than that in response to the songs. The zonosaurs stopped foraging for a longer time in response to the alarm calls than to the songs. These results demonstrate that Z. laticaudatus has the ability to eavesdrop on alarm calls of the Madagascar paradise flycatcher. It is suggested that heterospecific eavesdropping by non-vocal lizards is a common phenomenon, at least, in the Ampijoroa forest of Madagascar.
In recent years, cannibalism has been increasingly documented in larval amphibians and anecdotal observations suggested that tadpoles of Polypedates braueri (Rhacophoridae) exhibit this unusual feeding behavior. To test these observations, we conducted a laboratory experiment where we manipulated both density and food quantity in P. braueri tadpoles. However, there were no significant differences in survival among treatments and no instances of cannibalism were observed during the course of the experiment in any treatments. Despite using conditions that might facilitate cannibalism (low food, high density), we were unable to experimentally confirm its existence under the conditions examined.
Montivipera bornmuelleri is an endangered viper that has been described as endemic to the Lebanese mountains. The lethal dose 50% (LD50) of M. bornmuelleri venom has been determined by performing intravenous, intraperitoneal (IP), and subcutaneous injections. However, to date, intramuscular injection has not been performed to determine LD50, nor have the minimum hemorrhagic (MHD) or the minimum necrotic doses (MND) been evaluated. Thus, this study was conducted to complete the characterization of the M. bornmuelleri venom. Our results showed that intramuscularly injected LD50 is around 5.39 mg/kg, and IP LD50 is around 1.93 mg/kg. After intradermal injection, our findings showed significant necrotic and medium hemorrhagic activities, and MHD was around 250 μg/kg. By comparing with other local venomous snakes, these results indicate that the lethality of M. bornmuelleri venom is similar to that of Daboia palaestinae venom (IP LD50=1.9 mg/kg) and is higher than that of Macrovipera lebetina venom (IP LD50=7.58 mg/kg) and that the hemorrhagic activity of M. bornmuelleri venom is lower than that of the Macrovipera lebetina (MHD=200 μg/kg). On the other hand, necrotic activity was detected at low doses of injected venom: MND was estimated at 20 μg/kg. Altogether, our findings could extend the scope of characterization of M. bornmuelleri venom and provide useful data for further in vivo studies.
Populations of the montane brown frog, Rana ornativentris, endemic to Japan, have been declining abruptly due to habitat loss and destruction by land development, and thus genetic diversity of this species is needed for clarifying the demographic status and conservation measures of this species. However, there were no appropriate genetic markers to elucidate such genetic diversities in population and individual level. We therefore developed microsatellite markers of R. ornativentris utilizing Ion PGM™ sequencing. As a result of the screening, a total of 23 polymorphic markers were developed. To test the usefulness of these markers for population genetic analysis, we genotyped two regional populations: an eastern population (Akiruno-shi, Tokyo) and a western population (Kita-hiroshima-cho, Hiroshima Pref.). The total number of alleles and expected heterozygosities per locus ranged from 3 to 11 and 0.000 to 0.875, respectively. The markers described here will be useful for studying population genetics and planning conservation managements of R. ornativentris.
In March 2015, we observed mating behavior of loggerhead turtles in the western coastal waters of Okinawa Island, Japan. Two males and one female were initially involved, of which one of the males (M1) was attempting to mount the other male (M2) that had already mounted the female. Shortly after the onset of observation, M1 dismounted from M2 and swam away. At that time, the female, initially seemingly resisting copulation with M2, became receptive. This is the first report of loggerhead turtle mating behavior that involves more than two individuals. This observation suggests that the mating season of loggerheads around Okinawa Island includes the early spring.