We record a tree frog of the genus Chiromantis for the first time from outside the Southeast Asian continent and describe it as a new species, Chiromantis inexpectatus. The new species from the Malaysian state of Sabah, Borneo, is a small-sized Chiromantis (male snout-vent length ca. 22 mm), and is distinguished from all other members of the genus by the combination of the following morphological characteristics: dark stripes absent, but dark spots present on dorsum; a dark-brown lateral band present from snout tip to half of body, bordered ventrally by white stripe; third and fourth fingers less than half webbed; third finger disk wider than tympanum diameter; and inner metatarsal tubercle present. Significance of findings of this species from Borneo Island, as well as phylogeny and breeding habit of the genus Chiromantis, are briefly discussed.
We describe a new species of torrent-dwelling ranid frog of the genus Meristogenys from the Crocker Range, western Sabah, northern Borneo. The new species, Meristogenys maryatiae, differs from congeners by the combination of: small body, males 31-37 mm and females 65-66 mm in snout-vent length; head narrower than long; eyes moderate, diameter subequal to snout; iris unicolored; legs long; ventral surface of tibia without heavy pigmentation; rear of thigh blotched dark brown and cream; toes fully webbed; outer metatarsal tubercle present; larval dental formula 7(4-7)/6(1).
Two forms of Staurois that are differentiated by body size occur parapatrically in the Crocker Range, Sabah, Borneo. Analyses of a total of 1,499 bp of the mitochondrial cytochrome b, 12S rRNA, and 16S rRNA genes revealed that the two forms could be completely split genetically. The two forms could be also clearly differentiated morphologically, not only by snout-vent length but also by the relative sizes of snout, eye, and finger disk. Comparisons of the two forms with all known species of the genus revealed the large and small forms to be S. tuberilinguis and S. parvus, respectively. The latter species has long been synonymized with the former, but we here consider them to represent different species.
A cryptic Bornean torrent frog of the genus Meristogenys, which is divergent genetically and morphologically from all known congeners, is described from mountain streams of western Sarawak, East Malaysia (Borneo). The species occurs sympatrically with the type species of the genus, M. jerboa, but apparently differs from it in adult coloration and larval morphology, such as keratodont formulae and glands in tail fins. Females of the new species possess much larger and fewer eggs than in sympatric M. jerboa, suggesting significantly different reproductive traits between these species. A key to larvae of known species of the genus is provided.
The genus Rana, notably diversified in Oriental regions from China to Southeast Asia, includes a group of cascade frogs assigned to subgenera Odorrana and Eburana. Among them, R. ishikawae and the R. narina complex represent the northernmost members occurring from Taiwan to the Ryukyu Archipelago of Japan. Relationships of these frogs with the continental members, as well as the history of their invasions to islands, have been unclear. The taxonomic status of Odorrana and related genera varies among authors and no phylogenetic reassessment has been done. Using partial sequences of mitochondrial 12S and 16S rRNA genes, we estimated phylogenetic relationships among 17 species of the section Hylarana including Odorrana and Eburana, and related species from the Ryukyus, Taiwan, China, Thailand, Malaysia, and Indonesia. We estimate that (1) Odorrana is monophyletic and encompasses species of Eburana and R. hosii, which is now placed in Chalcorana, (2) the ancestor of R. ishikawae separated from other Rana in the middle to late Miocene prior to its entry to the Ryukyu Archipelago, (3) the ancestor of the R. narina complex later diversified in continental Asia, and invaded the Ryukyu Archipelago through Taiwan, (4) the R. narina complex attained its current distribution within the Ryukyus through niche segregations, and (5) vicariance of R. hosii between Malay Peninsula and Borneo occurred much later than the divergence events in the R. narina complex. Current subgeneric classification of Rana, at least of Southeast Asian members, requires full reassessment in the light of phylogenetic relationships.
Of 97 strains of Vibrio cholerae isolated from various seafoods in Malaysia in 1998 and 1999, 20 strains carried the ctx gene and produced cholera toxin. Fourteen, one, and five of these toxigenic strains belonged to the O139, O1 Ogawa, and rough serotypes, respectively. The rough strains had the rfb gene of the O1 serotype. The toxigenic strains varied in their biochemical characteristics, the amount of cholera toxin produced, their antibiograms, and the presence or absence of the pTLC plasmid sequence. DNA fingerprinting analysis by arbitrarily primed PCR, ribotyping, and a pulsed-field gel electrophoresis method classified the toxigenic strains into 3, 7, and 10 types, respectively. The relatedness of these toxigenic strains to clinical strains isolated in other countries and from international travelers was examined by using a dendrogram constructed from the pulsed-field gel electrophoresis profiles. The results of the examination of the antibiogram and the possession of the toxin-linked cryptic plasmid were consistent with the dendrogram-based relatedness: the O139 strains isolated from Malaysian seafoods could be separated into two groups that appear to have been introduced from the Bengal area independently. The rough strains of Malaysian seafood origin formed one group and belonged to a cluster unique to the Thailand-Malaysia-Laos region, and this group may have persisted in this area for a long period. The single O1 Ogawa strain detected in Malaysian seafood appears to have an origin and route of introduction different from those of the O139 and the rough strains.
By investigating genealogical relationships, we estimated the phylogenetic history and biogeography in the megophryid genus Leptobrachium (sensu lato, including Vibrissaphora) from southern China, Indochina, Thailand and the Sundaland. The genealogical relationships among the 30 named and unnamed taxa were estimated using 2009 bp of sequences from the mitochondrial DNA genes 12S rRNA, tRNA(val), and 16S rRNA using maximum parsimony, maximum likelihood, and Bayesian inference methods. The genus Leptobrachium was a well-supported monophyletic group that contained two major clades. One clade had three subclades primarily from disjunct regions including Borneo, Peninsular Malaysia and Java, and Thailand. The Bornean subclade included one species each from the Philippines and Sumatra. The other major clade consisted of two subclades, one from Indochina and the other from southern China (Vibrissaphora). Divergence times estimated an old evolutionary history of each subclade, one that could not be explained by the geohistory of Southeast Asian major landmasses.
A fanged frog Limnonectes kuhlii was once thought to be wide-ranging in Southeast Asia, but is now confined to its type locality Java through recent phylogenetic studies, which clarified heterospecific status of non-Javanese populations, and monophyly of Bornean populations. However, large genetic differences among Bornean populations suggest occurrence of cryptic species, which we test using dense geographic sampling. We estimated the phylogenetic relationships among samples of Bornean populations together with their putative relatives from the continental Southeast Asia, using 2517bp sequences of the 12S rRNA, tRNA(val), and 16S rRNA of mitochondrial DNA, and 2367bp sequences of the NCX1, POMC, and RAG1 of nuclear genes. In the mtDNA trees, Bornean L. kuhlii-like frogs formed a monophyletic group split into 18 species lineages including L. hikidai, with the deepest phylogenetic split separating L. cintalubang from the remaining species. Almost all of these lineages co-occur geographically, and two to three lineages were found syntopically in each locality. Co-occurrence of more than one lineage may be maintained by differential morphology and microhabitat selection. These syntopic lineages should be regarded as distinct species. Our results clearly indicate that taxonomic revision is urgent to clarify many evolutionary problems of Bornean L. kuhlii-like frogs.