We studied the feeding ecology of Eutropis multifasciata in the tropical plains of central Vietnam to understand better the foraging mode, spatiotemporal and sexual variation in dietary composition, and rarefaction curves of prey-taxon richness for males and females. Stomach contents (n = 161) were collected from October 2013 to May 2014 using a nonlethal stomach-flushing technique. A total of 680 food items (624 animal items and 56 plant items) was found in 161 stomachs of skinks, representing 19 unique animal categories. We found that the diet of E. multifasciata is composed mainly of small, sedentary and clumped prey and that this skink specialises on spiders, insect larvae, snails, grasshoppers and crickets (with a combined importance index of 60%). Dietary composition, prey size and total prey volume in E. multifasciata changed between dry and rainy seasons and among regions. The total volume of food items consumed by males was larger than that of females, and the diversity and evenness index of prey categories were larger in males than in females. However, using rarefaction curves revealed that females have the higher prey-taxon richness after points between 130 and 140 prey items for frequency, and between 160 and 170 prey items for number of items, and the differences were not statistically significant. The foraging behaviour of E. multifasciata best fits a 'widely foraging' model.

Background: We examined differences in reproductive activities and intraspecific variations in advertisement calls of Duttaphrynus melanostictus (Schneider, 1799) that lives in a tropical region of central Vietnam. The snout-vent length (SVL) of sexually mature males ranged from 50.2 to 70.3 mm, while that of females ranged from 65.2 to 97.3 mm. Histological analyses of testes revealed that sperm was not present throughout the year, indicating discontinuous reproductive activity for adult males. Adult females were captured year-round, but reproductive females were observed only during months of the auxiliary rainy season (mainly April to July), indicating that females reproduce seasonally. We also estimated levels of within-male variation of each call property and the influences of the ambient temperature, humidity, and the SVL of calling males on acoustic features. Results: The call rate and pulse rate showed intermediate levels of variation, whereas the dominant frequency and call duration were the most stereotyped properties. One-way analyses of variance for six acoustic properties showed that the call rate, pulse rate, and rise time significantly differed (p < 0.05) among localities. Advertisement calls were a series of groups of 56 to 244 (145 ± 54) pulses with an average call duration of 26.722 s, an average pulse rate of 11.69 pulses/s, and an average dominant frequency of 1.293 kHz. The results of the multiple regressions for possible effects of temperature, humidity, and SVL on the six acoustic properties indicated that the dominant frequency, pulse rate, call duration, and rise time were positively significant. Conclusions:In Bach Ma National Park, when air temperature in the recording area decreased to <16.6°C, and advertisement calls of adult males virtually ceased in all three populations.

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Little is known about many aspects of the tadpole ecology of Quasipaa verrucospinosa (Bourret, 1937), whereas this species has also been classified as Near Threatened (NT) due to habitat change and degradation, loss of forest and stream habitats and overexploitation. We conducted experiments in the field and collected tadpole data to estimate survival rates, growth rates, and age at metamorphosis. The average number of tadpoles per clutch was 518, the average survival ratio at the final stage of metamorphosis was 80%, and the total time to metamorphosis averaged 55.8 days. Multiple regression results for possible effects of water temperature, dissolved oxygen, and pH values on survival rates and the total time of tadpole metamorphosis were significant among localities. Water temperature and dissolved oxygen, but not pH values, were negatively associated with the survival ratio and metamorphosis time of tadpoles. At the beginning stage of metamorphosis (41 – 42), tadpoles had an average body weight of 2.7 g, a snout-vent length (SVL) of 24.8 mm, a tail length of 40.5 mm, and a total length of 65.3 mm. The process of metamorphosis is completed in stage 46, at which juvenile frogs had a mean body weight of 2.3 g and a mean SVL of 25.8 mm. We used a two-way multivariate analysis of variance to examine the effects of year and site factors on the variance in morphological measurements and body weightes of tadpoles. This analysis revealed that body sizes of tadpoles varied significantly among years, sites, and by site-year interaction. Water temperature and dissolved oxygen have major impacts on rates of growth, timing of metamorphosis, and body size of tadpoles at metamorphosis.

Amphibian species are rarely detected with perfect accuracy, regardless of the method employed. A large-scale assessment for Quasipaa verrucospinosa occupancy was conducted at 35 sites in the primary forest and 42 sites in the secondary forest of Bach Ma National Park, central Vietnam. Based on the detection data for each site, the distribution of Q. verrucospinosa was estimated in different habitat types using occupancy models. From the best model among all performed models, we estimated a site occupancy probability of 0.576 that was higher than the naive occupancy estimate of 0.403 and a 43.1% increase over the site proportion at which Q. verrucospinosa was actually observed. The site covariate of the primary forest was an important determinant of site occupancy, which was not associated with the variable of secondary forest. In a combined AIC model weight: the p(temperature), p(humidity), and p(precipitation) models have 47.3, 67.1, and 90.9% of the total, respectively; providing evidence that aforementioned environmental conditions were important sample covariates in modelling detection probabilities of Q. verrucospinosa. Our results substantiate the importance of incorporating detection and occupancy probabilities into studies of habitat relationships and suggest that the primary forests associated with weather conditions influence the site occupancy of Q. verrucospinosa in Bach Ma National Park, central Vietnam.

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We describe a new species of megophryid frog from Phu Yen Province in southern Vietnam. Leptolalax macrops sp. nov. is distinguished from its congeners by a combination of the following morphological attributes: (1) body size medium (SVL 28.0–29.3 mm in three adult males, 30.3 mm in single adult female); (2) supra-axillary glands present, creamy white; ventrolateral glands indistinct; (3) tympanum externally distinct; (4) dorsal skin roughly granular with larger tubercles, dermal ridges on dorsum absent; (5) rudimentary webbing present between fingers I–II and II–III; rudimentary webbing between all toes; fingers and toes without dermal fringes; (6) in life ventral surface greyish-violet with white speckling; (7) supratympanic fold distinct, dark brown in life; (8) iris bicolored, typically golden in upper half, fading to golden green in lower half; (9) tibia short (TbL/SVL 0.44–0.45 in males); and (10) eyes large and protuberant (ED/SVL 0.15–0.16 in males). From all congeners for which comparable sequences are available, the new species differs markedly in the 16S rRNA mitochondrial gene sequence (P-distance>5.7%). The new species is currently known only from montane evergreen tropical forests of Song Hinh District, Phu Yen Province, and M’Drak District of Dak Lak Province at elevations of 470–630 m a.s.l.. We suggest the new species should be considered as Data Deficient following the IUCN’s Red List categories. We also report a previously unknown Leptolalax mtDNA lineage from an evergreen tropical forest in the Hoa Thinh District of Phu Yen Province, which may also represent an undescribed species.