Over the past two decades, amphibian conservation has been a growing concern with the realization of worldwide amphibian declines and high prevalences of frog deformities. Chemical contaminants have attracted significant attention as a causative agent of these amphibian abnormalities. Japanese amphibians also seem to decrease in number, and deformed frogs have been frequently observed in the Kitakyushu area. Toxicity or teratogenicity tests conducted with Japanese amphibian larvae or Xenopus laevis embryos indicate that the most common herbicide in Japan and some organic compounds detected from the Kitakyushu area have the potential to induce amphibian mortality or malformation. However, these toxicological data have limited relevance to the amphibian abnormalities occurring in the field. In general, laboratory tests conducted by use of wellcontrolled and standardized methods provide only the basic data to evaluate the toxicity of chemicals. Various biological and physical-chemical factors such as geographic, ecological, and physiological diversity in amphibians, susceptibilities that may be variable during larval stages, and environmental fate of chemical contaminants should be in consideration for the risk assessment. Mathematical models may facilitate to assess the effects of chemicals using these complex factors. Amphibian toxicology should therefore make connections with developmental biology, ecology, physiology, mathematical biology, and physical chemistry. Extensive and interdisciplinary investigation would be required to progress toward amphibian conservation focusing on the protection of wild amphibians from chemical contaminants.

View full abstract

Two reptiles, Mauremys mutica kami and Hemiphyllodactylus typus typus, are newly recorded from Haterumajima, the southernmost island of the Yaeyama Group, southern Ryukyus, on the basis of voucher specimens. Of these, M. m. kami was found in large number, and this strongly suggests that this freshwater turtle has already established a breeding population on this island. With respect to H. t. typus, only one individual, juvenile female, was found. However, considering possible parthenogenetic nature of its East Asian assemblages, this gecko may have also established on this island already. Besides these new records, our survey yielded additional specimens of Lepidodactylus lugubris, another parthenogenetic gecko non-native to Haterumajim Island. Characteristics of the dorsal pattern in these specimens indicate that the Haterumajima assemblage belongs to so-called “clone C” like assemblages of this gecko from all other islands of the Ryukyus exclusive of the Daito Group. Records of reptile species from this island are reviewed and problems requiring future investigations are clarified.

View full abstract