First reproduction of Panha’s crocodile newt Tylototriton panhai in captivity, with a description of the courtship behaviour, eggs and larval development

Abstract

Amphibians are facing extinction on a global scale and maintaining small populations of threatened or endangered species in captivity is essential. In connection with potential captive breeding of Panha’s crocodile newt, Tylototriton panhai, we report a detailed husbandry protocol and describe breeding and mating behaviour. After six years in captivity, a group of two adult females and six males, tentatively identified as T. panhai, successfully reproduced for the first time on 24th June 2020 after a heavy rainstorm and two subsequent days of precipitation when water temperatures in a large aquaterrarium placed outdoors were 18-21 °C. The complete courtship behaviour consisted of five main stages: i/ approach; ii/ nuptial dance; iii/ amplexus; iv/ spermatophore deposition; v/ fertilisation. The two females laid a total of 84 eggs (41 and 43 eggs each) that were deposited on land in clutches of 4-22 eggs or even singly. Egg size averaged 12.6 ± 0.4 mm and the mean size of the embryo capsule 5.1 ± 0.1 (n=84). The egg hatch success rate was ~80% and on hatching the larvae moved to the water at the bottom of the aquaterrarium. By 7-9 days after hatching the total larval length was 11.89-13.78 mm (n=67). Diagnostic morphological characters are provided for stages 30-46. Metamorphosis occurred at 99-102 days and efts started to move to land at an average total length of 56.2 mm and weight of 0.6-0.9 g