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We describe a new species of dicroglossid frog of the Fejervarya limnocharis complex from western Honshu, Japan Mainland. The new species, Fejervarya kawamurai, is genetically closer to F. sakishimensis than to F. limnocharis. It differs from F. sakishimensis by smaller tympanum, head, forelimb, hindlimb, foot, and tibia lengths, all relative to snout-vent length, and from F. multistriata by relatively shorter forelimb, hindlimb, foot, and tibia. From F. limnocharis and F. iskandari, it is differentiated by relatively smaller forelimb, hindlimb, foot, and tibia lengths. Taxonomic problems of Fejervarya populations occurring in Central Ryukyus, continental China, and Taiwan are discussed.

In order to elucidate the taxonomic status of the Fejervarya limnocharis complex relative to Malaysia and Japan populations, morphological observations and molecular phylogenetic analysis were carried out using three populations from Indonesia (type locality), Malaysia, and Japan. In addition, we conducted histological and spermatogenic observations using hybrids among these populations. Principal component and cluster analyses demonstrated that these populations could be clearly separated from one another. Abnormal testes were found in the hybrids between the Japan and Indonesia populations and between the Japan and Malaysia populations, but testes of the controls and hybrids between the Malaysia and Indonesia populations were quite normal. The mean number of univalents per cell was 5.42, 4.58, and 0.20 in hybrids between the Indonesia and Japan populations, Malaysia and Japan populations, and Indonesia and Malaysia populations, respectively. Sequence divergences in 16S rRNA and Cyt b genes were 0–0.4% (x–=0.2%) and 0.3–1.5% (x–=1.0%), respectively, between the Malaysia and Indonesia populations, and 2.4–2.6% (x–=2.5%) and 11.0–12.0% (x–=11.5%) between the Japan population and F. limnocharis complex, including the Malaysia and Indonesia populations and F. multistriata from China. This study indicated that the Malaysia population and F. multistriata from China should be designated as a subspecies of topotypic F. limnocharis, and that the Japan population should be regarded as a distinct species.

In order to elucidate the taxonomic status of the Fejervarya limnocharis complex relative to Malaysia and Japan populations, morphological observations and molecular phylogenetic analysis were carried out using three populations from Indonesia (type locality), Malaysia, and Japan. In addition, we conducted histological and spermatogenic observations using hybrids among these populations. Principal component and cluster analyses demonstrated that these populations could be clearly separated from one another. Abnormal testes were found in the hybrids between the Japan and Indonesia populations and between the Japan and Malaysia populations, but testes of the controls and hybrids between the Malaysia and Indonesia populations were quite normal. The mean number of univalents per cell was 5.42, 4.58, and 0.20 in hybrids between the Indonesia and Japan populations, Malaysia and Japan populations, and Indonesia and Malaysia populations, respectively. Sequence divergences in 16S rRNA and Cyt b genes were 0-0.4% (xbar=0.2%) and 0.3-1.5% (xbar=1.0%), respectively, between the Malaysia and Indonesia populations, and 2.4-2.6% (xbar=2.5%) and 11.0-12.0% (xbar=11.5%) between the Japan population and F. limnocharis complex, including the Malaysia and Indonesia populations and F. multistriata from China. This study indicated that the Malaysia population and F. multistriata from China should be designated as a subspecies of topotypic F. limnocharis, and that the Japan population should be regarded as a distinct species.

The rice frog (Fejervarya limnocharis) species complex is widely distributed, from India to Japan, and most prevalently in Southeast Asia. Conspicuous morphological variation has been reported for this species complex throughout its distribution range. In the present study, we used mtDNA gene sequence and allozyme analyses to infer evolutionary affinities within this species complex using eight populations (Sri Lanka; Bangkok and Ranong in Thailand; Taiwan; and Hiroshima, Okinawa, Ishigaki and Iriomote in Japan). We also conducted crossing experiments among four populations from Japan, Thailand, and Sri Lanka in order to find out more about the reproductive isolating mechanisms that might exist among the East, Southeast, and South Asian populations of this species complex. The crossing experiments revealed that the Sri Lanka population is reproductively isolated from the Hiroshima, Bangkok, and Ranong populations by complete hybrid inviability, and that the Bangkok population may be reproductively isolated from the Hiroshima population by partial hybrid inviability. Thus, it is not unreasonable to regard the Sri Lanka population as a species separated from F. limnocharis. The mtDNA and allozyme data showed that the Ranong population is most closely related to the Bangkok population in nuclear genome, but more similar to the Okinawa and Taiwan populations in mtDNA genome. The present, preliminary survey may raise questions about the species status of these particular populations and also about the nature of the biological species concept.

We investigated the composition, diversity, and patterns of spatial use of an anuran community following a wetland restoration project in a managed tropical monsoon forest in southern Taiwan. Anurans comprising eight species in seven genera and four families reached a mean density of 0.025+/-0.004 anurans m(-2) within a year. The three most important species in terms of frequency of occurrence and relative abundance all had an early appearance; only the most abundant Fejervarya limnocharis (62.2% of total accounts), however, remained present throughout the entire year. The distribution of anurans observed among habitat zones was non-random, with most records occurring in densely planted (42.8%) and running-water (23.9%) zones, and the fewest in a buffer zone adjacent to a paved road. Mean numbers of anurans were correlated with the mean percent vegetation cover among individually divided small pools. Microhyla ornate, M. heymonsi, Polypedates megacephalus, and F. limnocharis appeared to be more heterogeneous in their use of space than Buergeria japonicus. Species differed in their most frequently used habitat zones within the wetland site, with the pairs F. limnocharis and P. megacephalus, and M. ornate and Bufo melanostictus, exhibiting similar respective distributions among zones. Our study demonstrates the value of even a small, isolated wetland in contributing to and maintaining regional amphibian diversity. Patterns of spatial relationships of this anuran community have important implications for the conservation of local populations across species.