Lizards in the genus Xenosaurus are crevice-dwelling lizards. Their crevice-dwelling habit may constrain their ecology; thus one might predict there could be limited variation in several ecological traits among species. Here we report on aspects of the ecology of the recently described Xenosaurus fractus from the Sierra Nororiental of Puebla, Mexico and compare it to other species of Xenosaurus. Mean body temperature of X. fractus was 19.67°C. Body temperature was related to air temperature and substrate temperature. We found no difference in thermal ecology between males and females. Crevice use was not related to the individual’s body size, nor did male and females differ in crevice use. Crevice characteristics had limited effects on body temperature. Sexual size dimorphism was not present in body size or head size, except for dimorphism in the relative growth of head width with snout-vent length. Xenosaurus fractus ate mostly insects, with caterpillars the most important prey. In conclusion, the ecology of X. fractus is similar to other species of Xenosaurus in many ways. Of particular interest is the observation that X. fractus does not appear to be any more similar to its sister species X. tzacualtepantecus than it is to other species of Xenosaurus.
Amami tip-nosed frog (Odorrana amamiensis) is an endangered species endemic to Amami-Oshima Island and Tokunoshima Island, in Japan. This species is threatened by invasive species and habitat destruction. Although action is needed to protect them, the breeding ecology of O. amamiensis is poorly understood. A better understanding of its breeding ecology would contribute to conservation efforts. This study reports temporal changes in number of O. amamiensis breeding individuals in Kinsakubaru area, Amami-Oshima Island from the 28 Nov. 2015 to the 5 Dec. 2015. A 20 m transect line was set at a stream to count the number of O. amamiensis individuals at night and during daytime for eight days. Over 200 individuals were observed and many of them were breeding with lively mating calls around the small stream at night for three days. The high density of individuals decreased rapidly afterwards. This is the first report quantifying the temporal changes in number of breeding individuals of O. amamiensis. The species is usually nocturnal, but some individuals were observed at breeding sites during the daytime as well. Field research on O. amamiensis is usually conducted at night, but it can be risky because the nocturnal poisonous snake Habu (Protobothrops flavoviridis) also inhabits Amami-Oshima Island. The results suggested that field research during daytime was relatively safer and perhaps an easier approach to find breeding sites of O. amamiensis compared to searching at night.
We analyzed sexual dimorphism and reproductive characteristics (minimum size at sexual maturity, clutch size, and reproductive period) of females and males of Sceloporus cozumelae, a species endemic to the Yucatan Peninsula, Mexico, and which belongs to the Sceloporus variabilis group. Sexual dimorphism was recorded, with the males being larger in snout–vent length, head length, head width, forearm length, and tibia length. The average clutch size was 3.4. Females containing eggs and vitellogenic follicles were observed at the same time, indicating that the population produces at least two clutches annually. Minimum size at sexual maturity was similar for both sexes (40 mm), and reproduction, determined according to the months in which gonads were obtained, was synchronous between males and females. The species shows high similarity to populations of S. variabilis in sexual dimorphism and reproductive characteristics; however, it has smaller snout–vent length when compared to other populations of S. variabilis in Mexico.
The colubrid snake Phalotris nigrilatus is endemic to San Pedro Department (Paraguay) and is known from a very few historical specimens. We analyze morphological variation and geographic distribution of P. nigrilatus on the basis of currently available specimens, including long-overlooked museum material. Also, we briefly report for the first time its live coloration and behavior on the basis of a recently collected individual. Results of morphological and geographic analyses lead to a slight revision of diagnosis and an argument for a higher conservation priority for this species.
Biological invasions are major threats to global biodiversity, and island ecosystems are especially vulnerable. Many previous studies have reported the presence of invasive species on islands, but relatively few studies have quantified the population status of such species. Furthermore, multiple invasive species are often introduced to the same region or island. In such case, quantifying the relative abundance of each species would provide us with significant insight into their population dynamics and potential species interactions. Rhinella marina and Bufo gargarizans miyakonis were introduced to both Minami-daito and Kita-daito Islands before 1945. Although some studies have reported their invasion and establishment, few studies have quantified their relative abundance. To reveal their relative abundance, we set 5 km line transects and counted the number of each species from 11 to 31 July 2019. We applied generalized linear models to examine the relationship between the number of individuals observed with species and environmental factors. We also applied these models to examine the relationship between the number of individuals observed with island and environmental factors. We found the relative abundance of R. marina was significantly higher than that of B. g. miyakonis on Minami-daito Island. This is the opposite pattern of 30 years ago, suggesting the population dynamics of these invasive toads is unstable on Minami-daito Island. Although B. g. miyakonis was found on both islands, no individual of R. marina was found on Kita-daito Island. The population dynamics may depend on environmental differences between islands and ecological differences between species. Future studies are needed to reveal the potential factors determining the differences in relative abundance between islands and between species.
The Eastern-Japanese common toad, Bufo japonicus formosus, is distributed from southern Hokkaido to Kinki district of northeastern Honshu, Japan. However, Hokkaido populations are suspected to be nonnative and derived from relatively recent artificial introduction from Honshu. To clarify the origin of Hokkaido populations, we analyzed sequence variations of the mitochondrial cytochrome b gene in the toads from Hokkaido and compared the sequence data from previous studies. We obtained ten haplotypes from six sites on Hokkaido. Samples from the sites located along Ishikari river system, Asahikawa, Ebetsu, and Ishikari cities, had six haplotypes. Only one haplotype was obtained in Sapporo city and it was genetically far from Ishikari river’s ones. Hakodate and Muroran cities samples had one and two haplotypes, respectively. All ten haplotypes from Hokkaido were genetically identical or close to haplotype data from Kanto district or Shizuoka Prefecture, mid-eastern Honshu, far from Hokkaido. Therefore, the toad populations of Hokkaido were considered to be nonnative and multiple introductions from eastern Honshu to Hokkaido were implied.
Basic ecological understanding is important for effective management of introduced species. If the species is rare or threatened in its native ranges, ecological knowledge gained from its introduced ranges may offer useful information for conservation. We radio-tracked 12 adult Physignathus cocincinus in Hong Kong, where it is introduced, to investigate their home range, movements, and habitat use. The home range of all P. cocincinus covered the stream, but 66% of relocations occur >5 m away from the stream. Movements did not differ between sexes and seasons. Females stayed at a longer distance from the stream than males. Lizards preferred woodland and concrete structures over orchards. For microhabitats, they preferred wider streams, greater height, and denser canopy cover. This infers the high association of this species with streams and riparian forests, which may be crucial for the establishment of introduced populations. To effectively manage the introduced populations through eradication efforts, areas away from streams (5–100 m) needs to be covered.
Gekko yakuensis and G. tawaensis, both endemic to western Japan, are threatened by genetic introgression from G. hokouensis and G. japonicus, respectively. To know detailed situation of their hybridizations for planning relevant conservation measures, development of sensitive genetic markers is desired. We here developed microsatellite markers based on the sequences obtained from G. hokouensis using 454 GS Junior sequencer, and tested stability of PCR amplification and species-specificity of alleles at each locus using G. hokouensis, G. yakuensis, G. japonicus, and G. tawaensis. The results showed that 22 loci were almost constantly amplified in more than one species. We further confirmed that there were fixed or nearly fixed allelic displacement between G. hokouensis and G. yakuensis, and between G. japonicus and G. tawaensis at 14 loci. Thus, these 22 loci are considered to be useful for evaluation of hybridizations between these pairs of species.
We describe a specimen of Karsenia koreana, the only Asian plethodontid salamander, found in the herpetology collection of Ewha Woman’s University Natural History Museum (EWNHM), Republic of Korea. This specimen was collected in Daedun Mountain, North Jeolla Province on 8 May 1978 and subsequently misidentified as Hynobius leechii. Therefore, the collection of this particular specimen predates the formal description of the species by 27 years. We also remark on the specimen previously described by Nishikawa (2009) and an observation of K. koreana made in Baekun Mountain on 24 August 1999. These records altogether represent fuller historical data on records of this species prior to its formal description.
Animals that aggregate in leks to attract mates often time the production of their mating signals against the signals of neighboring conspecifics. Such signal timing usually falls into general patterns within these aggregations, which can be categorized based on the amount of overlap between the signals. In many species, individuals produce signals in an alternating pattern, avoiding signal overlap to reduce interference and increase mate attraction. In contrast, individuals in some species produce signals in synchrony, maximizing overlap and interference. The prevalence and function of signal synchronization is still unknown in many species. Here we examine the call timing strategies of the Ryukyu Kajika frog (Buergeria japonica). Using acoustic playback experiments we characterize a divergence in timing patterns between the two call types in this species, one produced in alternation and one in synchrony. Specifically, male B. japonica responded to playbacks of the first call type (Type I calls) with delayed Type I calls, avoiding overlap with the playbacks. In contrast, males responded to playbacks of the second call type (Type II calls) with synchronized Type II calls, overlapping their calls with the playbacks. Such variation in temporal signaling strategies within a species provides insights into how social and environmental pressures shape signal timings.