Although forest roads are known to have negative effects on wildlife, frogs often are observed sitting along small forest roads, possibly using them as hunting sites. To determine if forest roads can be attractive hunting sites for frogs, biomass and composition of potential prey on roads and in adjacent forest were compared. Sticky sheet traps were placed on the roads or 10 m inside adjacent forest overnight at 22 sites in subtropical secondary forest on Amami Island, Japan. Trapped invertebrates were categorized into 10 taxonomic groups, and their dry weights were estimated from body size using an allometric equation for each group. There was no difference in biomass or composition between on-road and in-forest trapped invertebrates. This work suggested that forest roads are not necessarily better foraging areas for frogs than adjacent forest in terms of the quantity and composition of prey.

View full abstract

Understanding the status of hylid frogs in Mexico is often hindered by a lack of understanding of basic natural history. We report on the natural history and phenology of H. plicata from the Arroyo Los Axolotes, Sierra de las Cruces, state of Mexico, as well as its co-occurence with Ambystoma altamirani. Adult Hyla plicata arrive at the stream in March and April, and oviposition takes place in June. Metamorphosis takes place in September and October. Hyla plicata are found in sites along the Arroyo las Axolotes that are wider and deeper, with higher levels of dissolved oxygen and slower water speeds than sites where they are not found. Their distribution is not affected by water temperature. Hyla plicata used sites with white-yellow and tan-brown substrates more than sites with black substrates. Types of substrates and vegetation at sites with and without H. plicata did not differ. Our results suggest that H. plicata requires stream reaches that are wider, deeper, and with slower flowing water, and that H. plicata and A. altamirani negatively co-occur.

View full abstract

Blood levels of progesterone (P₄), estradiol-17β (E₂), calcium (Ca), triglyceride (TG), and total protein (TP) were monitored in a captive female loggerhead turtle throughout a nesting season that included three 13- or 14-d internesting intervals. We observed the turtle’s ovaries to monitor the appearance of shelled eggs, using ultrasonography, and compared the results of blood analyses and ovary observations. The blood P₄ level remained low (<0.2 ng/mL), with the exception of three sharp peaks (1.7, 2.2, and 4.2 ng/mL) immediately after the initial three nestings. Eggshell formation occurred immediately after the P₄ peaks. The blood Ca level gradually dropped to approximately 3.0 μmol/mL during each eggshell formation period but then recovered to approximately 3.7 μmol/mL prior to the next eggshell formation. The blood E₂ level fluctuated between 44 and 299 pg/mL, but with two higher peaks (734 and 419 pg/mL) after eggshell formation in the first and second internesting intervals, respectively. During the nesting season, the blood TG level (initially 20 μmol/mL) showed a stepwise drop to 7.6 μmol/mL, while the blood TP level fluctuated between 57 and 69 mg/mL with no distinct peaks. The periodic cycle of P₄ and Ca changes aligned with albumen layer secretion around ovulated follicles immediately after nesting, followed by eggshell calcification in the clutch. The relatively small fluctuations in E₂, TG, and TP during the nesting season suggested that lipid deposition and preovulatory follicular development were completed prior to the start of nesting.

View full abstract

We investigated the genetic population structure of the Japanese grass lizard, Takydromus tachydromoides, based on polymerase chain reaction—restriction fragment length polymorphisms (PCR-RFLPs) and DNA sequence analyses of the mitochondrial cytochrome b gene. The PCR-RFLP analysis of 163 specimens collected from the main islands of Japan and the adjacent islands identified a total of 25 mitochondrial haplotypes (mitotypes). The phylogeny of the mitotypes revealed that Osumi and Tokara Island populations were remarkably diverged from all other populations on the main islands of Japan. Furthermore, several regional groups were also recognized at the western part of Japan, namely mitotype groups in Kyushu, those in the western Honshu, and those in the central Honshu and Shikoku. In contrast, little genetic diversity was observed throughout eastern Japan. The regional genetic differentiation and recent range expansion of this species are considered to be associated with past geological events and climate changes.

View full abstract

Three species/subspecies of toads (Bufo japonicus japonicus, B. j. formosus, and B. torrenticola) show parapatric/sympatric patterns of distribution in Japan, and usually they are morphologically indistinguishable at early developmental stages. For quick and easy genetic identification of these three toads, we validated LAMP assay. We designed taxon-specific primers for LAMP assay on mitochondrial cytochrome b region, and these primer sets accurately assigned DNA samples derived from three toads to each taxon. Due to its instancy and simplicity, LAMP method could be a useful diagnostic tool to distinguish taxa which resemble each other.

View full abstract

In the Japanese fire-bellied newt, Cynops pyrrhogaster, six local races were reported (Atsumi, Hiroshima, Kanto, Sasayama, Tohoku, and Intermediate) on the basis of morphological and ethological traits. Among them, the Atsumi race was reported only from a locality of the Atsumi Peninsula, Aichi Prefecture, but this race has been thought to be extinct after the 1960s. In the present study, we collected C. pyrrhogaster at a wetland of the Chita Peninsula, which is located west of the Atsumi Peninsula. The specimens resembled the Atsumi race in dorsal and ventral color pattern, absence of male nuptial color, small body size, and elongated filamentous process of tail tip. Newts from Chita differed from the Atsumi race in the tail height/tail length ratio, but this value was highly variable even among populations within another race (the Intermediate race). Judging from these results, we suggest that C. pyrrhogaster from the Chita Peninsula should be regarded as a part of the Atsumi race, which has long been thought to be extinct. Unfortunately, C. pyrrhogaster at Chita is also threatened with extinction, and immediate protection is seriously needed to prevent this enigmatic local race from complete extinction.

View full abstract

The nuchal and nucho-dorsal glands are unique defensive organs that have been found in only 13 species of Asian natricine snakes. In Rhabdophis such nuchal glands have been described in nine species, whereas the absence of the glands has been also reported in a few species, including R. adleri. We reexamined the absence/presence of the nuchal glands of R. adleri by dissection of two freshly dead individuals and a recently preserved specimen, as well as by careful reobservation of six type specimens, in which the absence of the glands had been reported. The glands were found both in the neck and along the entire length of the body in the three new specimens. We also confirmed the presence of the glands, at least in the anterior part of the body, in three type specimens. We conclude that the glands were simply overlooked in the original description and that R. adleri possesses nuchodorsal glands that extend over the full length of the body, including the neck region.

View full abstract

Lepidodactylus lugubris is one of the most widespread geckos distributed throughout tropical Asia and the Pacific, and some populations have been introduced to seasonal subtropical areas. On tropical islands, L. lugubris reproduces throughout the year, and it is considered potentially to be a continuous breeder. Generally reproduction in lizards is greatly affected by climate, and seasonality brings a cyclic reproductive pattern. Therefore, reproduction of invasive populations of L. lugubris in a seasonal subtropical area is likely to be affected by the climate there. In this paper, I report seasonal change in size distribution of L. lugubris in northern Okinawajima Island, Ryukyu Archipelago, Japan, where the species experiences a cold winter season. In early summer, most individuals were adults, and hatchlings did not exist. In autumn, both adults and hatchlings were found, and the size distribution was bimodal (a gap exists between two groups). The change of size distribution between the two seasons may be caused by the seasonal climate, and it suggests two non-exclusive possibilities: (1) cold winter may bring quiescence of reproduction, and (2) low temperature decreases hatching success of L. lugubris in northern Okinawajima Island.

View full abstract

Using mitochondrial DNA sequences, we surveyed genetic features of 12 individuals of Cynops pyrrhogaster introduced into Hachijojima Island, in order to estimate their possible origin in the main islands of Japan. The phylogenetic analysis revealed that the 12 examined newts of the introduced population display no genetic diversity and share characteristics with the conspecific population of Shikoku and thus belong to the WESTERN Clade proposed by earlier studies. Our results suggest that the Hachijojima population, having experienced a drastic founder effect, stems from very few individuals from the Shikoku District approximately 650 km to the west.

View full abstract

Antipredator behavior of Cynops pyrrhogaster was observed in the field. A male, found in a temporal pool (11.7C), tightly coiled his body around the observer’s finger (putative model of predator) when he was touched from lateral side. The body-coiling was formed both dextrally and sinistrally, depending on direction from which the newt’s body was touched. Undulation of tail and noxious secretion accompanied the behavior. The coiling-around behavior was aborted immediately when the newt lost physical contact with finger. Apart from this, pushing on the head with a finger caused Unken reflex, which is commonly known as defensive behavior of newts. It is suggested that C. pyrrhogaster varies their defensive behavior depending on the situation of encounter with the predator.

View full abstract