Current Herpetology Vol. 21, No. 1, June, 2002


Foraging Behavior of Rhabdophis tigrinus (Serpentes: Colubridae) in a Gutter with a Dense Aggregation of Tadpoles
Koji Tanaka
21(1): 1-8 Key words: Rhabdophis tigrinus; Foraging behavior; Anuran larvae; Aquatic prey; Ratio of successful strike

Abstract: Field observations were made on the foraging behavior of Rhabdophis tigrinus in a gutter where numerous Hyla japonica larvae aggregated. It seemed that not only chemical cues but also visual cues play important roles in the foraging behavior in this snake. Rhabdophis tigrinus performed predatory behaviors characteristic of generalists, not of aquatic specialists. Examinations of stomach contents revealed that froglets were the dominant prey item although tadpoles were seemingly more abundant in the gutter. It is likely that this biased predation on froglets is attributable to the differential vulnerability to predation among the developmental stages of the frog. The present observations support the idea that R. tigrinus is not well adapted to an aquatic life. Possible significance of success ratio of predatory attempt as an index is discussed.
Three New Depressed-bodied Water Skinks of the Genus Tropidophorus (Lacertilia: Scincidae) from Thailand and Vietnam
Tsutomu Hikida, Nikolai L. Orlov, Jarujin Nabhitabhata, and Hidetoshi Ota
21(1): 9-23 Key words: Tropidophorus, Scincidae, Thailand, Vietnam, New species, Taxonomy, Body depression, Rock crevices

Abstract: Three new species of the genus Tropidophorus, characterized by distinct depression of body, strongly keeled lateral body scales, and saxicolous habits, are described from Indochina. Of these, two moderately depressed species, one with undivided frontonasal and widened paravertebral scales, and the other with divided frontonasal and unwidened paravertebral scales, were collected from small areas in northeastern and eastern Thailand, respectively. The remaining species with extremely depressed head and body was found from one limited area in northern Vietnam. The three species most resemble T. baviensis Bourret, 1939 from northern Vietnam among the known congeneric species in body size, body shape, and scutellation. However, body depression in T. baviensis is not so prominent as in the present three species. Considering that most specimens of these species were collected from rock crevices, their characteristic body shapes may represent certain stages of adaptation to life in crevices.
Taxonomic Relationships of an Endangered Japanese Salamander Hynobius hidamontanus Matsui, 1987 with H. tenuis Nambu, 1991 (Amphibia: Caudata)
Masafumi Matsui, Kanto Nishikawa, Yasuchika Misawa, Masaichi Kakegawa, and Takahiro Sugahara
21(1): 25-34 Key words: Hynobiidae; Allozyme; Specific status; Conservation; Biogeography; Japan

Abstract: We assessed the taxonomic relationships of an endangered Japanese small salamander, Hynobius hidamontanus Matsui, 1987, and its close relative H. tenuis Nambu, 1991 electrophoretically and found that they were not clearly distinguished from each other. This result, together with available morphological and ecological information, strongly indicates that H. tenuis Nambu, 1991 is a subjective junior synonym of H. hidamontanus Matsui, 1987. By this conclusion, the total distribution range of H. hidamontanus is greatly expanded, but its endangered status and the necessity of its conservation is not be changed since the habitats of this species are fragmented and not continuous. The distribution pattern of this species is interesting from the viewpoint of biogeography.
Karyotypes of Four Agamid Lizards from Southeast Asia
Hidetoshi Ota, Cheong-Hoong Diong, Ene-Choo Tan, and Hoi-Sen Yong
21(1): 34-41 Key words: Karyotype; Chromosomal variation; Agamidae; Acanthosaura armata; Bronchocela cristatella; Calotes emma; C. versicolor; Southeast Asia.

Abstract: We karyotyped four lizards, Acanthosaura armata, Bronchocela cristatella, Calotes emma, and C. versicolor, all belonging to the tropical Asian clade of the family Agamidae. The karyotype of A. armata consisted of 12 metacentric macrochromosomes and 20 microchromosomes, whereas B. cristatella had 14 metacentric macrochromosomes and 20 microchromosomes. Except for the presence of 22 microchromosomes, the karyotypes of the two Calotes species were similar to that of A. armata. The 20 microchromosome state in the A. armata karyotype may have emerged in the ancestral lineage common to Gonocephalus robinsonii, whose karyotype also exhibits a 12M+20m format. Comparison of the present results with previously published information suggests the presence of cryptic taxonomic diversity in B. cristatella and C. versicolor.
Early Growth of Elaphe quadrivirgata from an Insular Gigantic Population
Akira Mori and Masami Hasegawa
21(1): 43-50 Key words: Elaphe quadrivirgata; Growth; Izu Islands; Insular gigantism; Snake

Abstract: Elaphe quadrivirgata on Tadanae-jima Island shows a clear insular gigantism. Based on data from captive animals, we compared growth rates over the first two years after hatching between this population and a conspecific population from the Japan mainland. The purpose of this experiment was to test the hypothesis that early growth rates in snakes in the insular gigantism population are higher than those in conspecific non-gigantic populations under the same feeding schedule. Growth rates in snout-vent length and body mass of Tadanae-jima snakes were not higher than those of main island snakes, and thus, the hypothesis was rejected. This result suggests that the gigantism in E. quadrivirgata on Tadanae-jima Island is not caused by a genetically based modification for rapid growth before maturation.
On the Authorship of Babina (Ampbibia: Ranidae)
Hidetoshi Ota and Masafumi Matsui
21(1): 51-53 Key words: Babina; Ranidae, Anura; Nomenclature; Authorship; Priority

Abstract: The genus-group name Babina, originally proposed as a full genus for Rana holsti (type species) and R. subaspera, is usually attributed to “Van Denburgh, 1912”. However, it is obvious from the chronological order of publication of relevant papers that the authorship of Babina should be “Thompson, 1912”, not “Van Denburgh, 1912”.
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