Taxonomic revision of the Southeast Asian brook barb genus Poropuntius Smith, 1931 (Teleostei, Cyprinidae) with description of a new species from Vietnam.

Molecular data from samples encompassing 22 nominal species of Poropuntius indicate that the species-level diversity in the genus has been vastly overestimated, likely due to inadequate taxon and geographic sampling and reliance on morphological characters that vary intra-specifically. The latter includes discrete mouth morphologies related to alternate feeding strategies (ecomorphs) within populations. One new species is described, Poropuntiusanlaoensis Hoàng, Pham & Tran, sp. nov., and 17 synonyms of six valid species names of Poropuntius, P.krempfi, P.alloiopleurus, P.huangchuchieni, P.laoensis, P.kontumensis, and P.deauratus, are recognised. Additional taxonomic changes in this widespread and generally poorly known genus are likely as more molecular and morphological data become available.

Natal origin and migration pathways of Mekong catfish (Pangasius krempfi) using strontium isotopes and trace element concentrations in environmental water and otoliths.

To improve our knowledge of the migration pathway of a highly threatened fish species along the Mekong River, strontium isotope ratios (87Sr/86Sr) and 18 trace element concentrations were measured in the water and in the otoliths of an anadromous catfish, Pangasius krempfi, to infer its natal origin and potential migration pathways. Water was sampled at 18 locations along the mainstream, tributaries and distributaries of the Mekong River. To check for accuracy and precision, measurements of the 87Sr/86Sr ratios and trace element concentrations were then compared in two laboratories that use different analytical methods. Differences in trace element concentrations between locations were not significant and could not, therefore, be used to discriminate between migration pathways. However, the Mekong mainstream, tributaries and distributaries could all be discriminated using Sr isotopes. The 87Sr/86Sr profiles recorded in P. krempfi otoliths showed that there were three contingents with obligate freshwater hatching and variable spawning sites along the Mekong mainstream, from Phnom Penh (Cambodia) to Nong Khai (Thailand) or further. After hatching, the fish migrated more or less rapidly to the Mekong Delta and then settled for most of their lifetime in brackish water. Spawning habitats and migration routes may be threatened by habitat shifts and the increasing number of hydropower dams along the river, especially the contingents born above Khone Falls (Laos). The conservation of P. krempfi, as well as other migratory fish in the Mekong River, requires agreements, common actions and management by all countries along the Mekong River. This study highlighted the importance of using both Sr/Ca and 87Sr/86Sr ratios to understand life history of anadromous fishes as the 87Sr/86Sr ratio in the water was shown to be less effective than the Sr/Ca ratio in identifying movements between different saline areas.

-A new species of phytotelm breeding frog (Anura: Rhacophoridae) from the Central Highlands of Vietnam.

We describe a new species of phytotelm-breeding rhacophorid frog from central Vietnam. Gracixalus trieng sp. nov. is distinguished from all congeners by a combination of (1) body size medium (37.2-41.4 mm in five adult males), (2) snout rounded in dorsal and lateral views, (3) dorsal surface brown or yellowish with a darker brown interorbital crossbar and inverse-Y shape on the back, (4) throat and chest yellow or yellowish brown with pinkish mottling and belly and ventral surfaces of limbs including hands and feet pinkish, (5) tympanum and supratympanic fold distinct, (6) iris pale gold with darker gold radiating out from anterior and posterior edges of pupil, (7) majority of dorsal body and limb surfaces smooth in adults, with some individuals having sparsely distributed low, irregular tubercles, (8) nuptial pads on fingers I and II in adult males, and (9) eggs deposited as a tightly spaced array of non-pendent eggs on the wall of a phytotelmon. The species occurs in syntopy with G. lumarius. At present, Gracixalus trieng sp. nov. is known only from montane bamboo and evergreen forest (>1700 m) on Mount Ngoc Linh and adjacent peaks; and it is likely to be restricted to high-elevation forest with an estimated geographical distribution of <1000 km2.

Mahseers genera Tor and Neolissochilus (Teleostei: Cyprinidae) from southern Vietnam.

Two new species and two new basin records of mahseers in the genera Tor and Neolissochilus are described from the upper Krong No and middle Dong Nai drainages of the Langbiang Plateau in southern Vietnam. These new species and new records are known from streams and rivers in montane mixed pine and evergreen forests between 140 and 1112 m. Their populations are isolated in the Sre Pok River of the Mekong basin, the middle of the Dong Nai basin, and the An Lão River. Both new species are differentiated from their congeners by a combination of the following characters: 23-24 lateral scales, 9-10 predorsal scales, 2/7 or 1/8 pelvic-fin rays, mouth position, median lobe of lower lip, rostral hood, colour in life and by divergent mitochondrial DNA. Tor mekongensis sp. nov. is differentiated from Tor dongnaiensis sp. nov. by the number of transverse scale rows (3/1/2 vs. 4/1/2), number of pelvic-fin rays (2/7 vs. 1/8), a blunt rostral hood vs. pointed, caudal-fin lobes that are equal vs. unequal, and by mitochondrial DNA (0.7% sequence divergence). Molecular evidence identifies both species as members of the genus Tor and distinct from all congeners sampled (uncorrected sequence divergences >1.9% for all Tor species for which homologous COI sequences are available). Tor sinensis is recorded in the Krong No and the Sre Pok rivers, further south of its known distribution. Polymorphism is described in Neolissochilus stracheyi with a Tor-like morph and a Neolissochilus-like morph.

Two new species of shovel-jaw carp Onychostoma (Teleostei: Cyprinidae) from southern Vietnam.

Two new species of large shovel-jaw carps in the genus Onychostoma are described from the upper Krong No and middle Dong Nai drainages of the Langbiang Plateau in southern Vietnam. These new species are known from streams in montane mixed pine and evergreen forests between 140 and 1112 m. Their populations are isolated in the headwaters of the upper Sre Pok River of the Mekong basin and in the middle of the Dong Nai basin. Both species are differentiated from their congeners by a combination of the following characters: transverse mouth opening width greater than head width, 14-17 predorsal scales, caudal-peduncle length 3.9-4.2 times in SL, no barbels in adults and juveniles, a strong serrated last simple ray of the dorsal fin, and small eye diameter (20.3-21.5% HL). Onychostoma krongnoensis sp. nov. is differentiated from Onychostoma dongnaiensis sp. nov. by body depth (4.0 vs. 3.2 times in SL), predorsal scale number (14-17 vs. 14-15), dorsal-fin length (4.5 vs. 4.2 times in SL), caudal-peduncle length (3.9 vs. 4.2 times in SL), colour in life (dark vs. bright), and by mitochondrial DNA (0.2% sequence divergence). Molecular evidence indicates that both species are members of Onychostoma and are distinct from all congeners sampled (uncorrected sequence divergences at the 16S rRNA gene of >2.0% for all Onychostoma for which homologous 16S rRNA sequences are available).

The breeding behaviour, advertisement call and tadpole of Limnonectes dabanus (Anura: Dicroglossidae).

Fanged frogs (Limnonectes) are a group of dicroglossid frogs from Asia that often have reversed sexual dimorphism with larger males. Limnonectes dabanus is a poorly known species of fanged frog from forested habitats in southern Vietnam and eastern Cambodia. Adult males exhibit an extreme degree of megacephaly and possess bizarre head ornamentation. L. dabanus breeds in shallow, non-flowing or very slow-flowing pools, puddles, and drainage ditches. Eggs are laid as a widely spaced array, and the larvae have a morphology typical of pond-dwelling tadpoles. Although males of the species lack vocal sacs, they produce a low-pitched (0.4-0.6 kHz), single-note advertisement call that sounds like a drop of water falling into water. Given the spacing of calling males, presence of multiple females near breeding sites, and reversed sexual dimorphism, the mating system of L. dabanus may be an example of resource-defense polygyny, and the massive head of the male is likely used in male combat.

A striking new species of phytotelm-breeding tree frog (Anura: Rhacophoridae) from central Vietnam.

We describe a distinctive new species of phytotelm-breeding rhacophorid frog from central Vietnam. Gracixalus lumarius sp. nov. is distinguished from all other rhacophorids in Indochina by a combination of (1) medium body size (adult males 38.9-41.6 mm; adult female 36.3 mm), (2) dorsum brown diurnally and yellow nocturnally, (3) venter pink, (4) tympanum and supratympanic fold indistinct (5) iris dark gold with a dense, relatively uniformly distributed network of black reticulations, (6) dorsum with distinctive white conical tubercles in males, and (7) eggs deposited on wall of a phyptotelm. The new species is known from montane bamboo and montane evergreen forest in Ngoc Linh Nature Reserve in Kon Tum Province, between ~1845-2160 m elevation.

Is chytridiomycosis an emerging infectious disease in Asia?

The disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has caused dramatic amphibian population declines and extinctions in Australia, Central and North America, and Europe. Bd is associated with >200 species extinctions of amphibians, but not all species that become infected are susceptible to the disease. Specifically, Bd has rapidly emerged in some areas of the world, such as in Australia, USA, and throughout Central and South America, causing population and species collapse. The mechanism behind the rapid global emergence of the disease is poorly understood, in part due to an incomplete picture of the global distribution of Bd. At present, there is a considerable amount of geographic bias in survey effort for Bd, with Asia being the most neglected continent. To date, Bd surveys have been published for few Asian countries, and infected amphibians have been reported only from Indonesia, South Korea, China and Japan. Thus far, there have been no substantiated reports of enigmatic or suspected disease-caused population declines of the kind that has been attributed to Bd in other areas. In order to gain a more detailed picture of the distribution of Bd in Asia, we undertook a widespread, opportunistic survey of over 3,000 amphibians for Bd throughout Asia and adjoining Papua New Guinea. Survey sites spanned 15 countries, approximately 36° latitude, 111° longitude, and over 2000 m in elevation. Bd prevalence was very low throughout our survey area (2.35% overall) and infected animals were not clumped as would be expected in epizootic events. This suggests that Bd is either newly emerging in Asia, endemic at low prevalence, or that some other ecological factor is preventing Bd from fully invading Asian amphibians. The current observed pattern in Asia differs from that in many other parts of the world.