Ecology and natural history of the knobby newt Tylototriton podichthys in Laos

Approximately 20 species of Tylototriton are currently recognized, with many new species having recently been described and species boundaries being uncertain. The genus is threatened by overexploitation for traditional medicine and the international pet trade. The amphibian fauna of Laos is relatively poorly known, with the genus Tylototriton being first reported from Laos with the description of T. notialis from Khammouan Province. A second species, T. podichthys, was recently described from Luang Phabang, Xiengkhouang, and Huaphanh Provinces, and is currently considered to be endemic to northern Laos. Tylototriton are harvested in Laos for the international pet trade and traditional medicine, and Laotriton laoensis, another newt species with a similar geographic range to T. podichthys, is listed as Endangered in the IUCN Red List of Threatened Species. A study was conducted to investigate the ecology and natural history of T. podichthys in Laos. The study site was located in an approximately 55,800 m2 area surrounding Houay Mor Stream at Yord Lieng Village, Kham District, Xiengkhouang Province, Laos. The site contained three distinct habitat types: forest, shrub forest, and a temporary stream. Daytime visual searching was conducted during four periods, totaling 29 days between June 2012 and July 2013, and newts were captured by hand and dipnet. Data were recorded for each captured newt, including habitat, substrate type, air temperature, stream water temperature, stream water pH, and air relative humidity. The study found that newts were abundant during the breeding season, with a maximum density of 8.75 newts in 100 m2 of stream. The sex ratio of adult males and females was almost equal and did not differ throughout the year. The population was sexually dimorphic, with females having larger and heavier bodies than males, and different cloacal morphologies during the breeding season. Males, females, and immature newts (efts) used a variety of habitat and microhabitat types. Adult newts occupied a stream only during a brief breeding period, but otherwise were primarily terrestrial. The diet of T. podichthys consisted primarily of terrestrial invertebrates, especially woodlice (Ligiidae), earthworms (Haplotaxida), and pillbugs (Armadillidae). Unlike in many other newts, conspecific oophagy was not observed. The diet composition, number of prey consumed, and volume of prey consumed did not differ among adult males, adult females, or efts. The study provides important information on the ecology and natural history of T. podichthys in Laos, which is essential for effective conservation of this species.