Wild observations of the reproductive behaviour and first evidence of vocalization in Crocodile newt Tylototriton himalayanus (Caudata: Salamandridae) from the Himalayan biodiversity hotspot in Eastern India

In this study, we provide the description of reproductive behaviour and also report the first evidence and description of vocalization in Tylototriton himalayanus, a recently described species from Eastern India and Nepal. Known variously as the Himalayan crocodile newt or orange-warted salamander, T. himalayanus is one of two known salamanders from the Himalayan Biodiversity hotspot in India. The study was conducted in the natural habitat of T. himalayanus, in Darjeeling district of West Bengal, during its breeding season. The observations were made in ephemeral ponds formed after the monsoon showers. Courtship behaviour and mating happened both during day and night. Operational sex ratio of the breeding population was skewed towards males as generally observed in amphibians. The males occupied the center of the pond and females were abundant on the periphery. Physical competition was observed among males for the possession of females. The courtship and amplexus lasts for about 90 min. After amplexus, the females laid about 1-9 eggs per oviposition site, and the entire egg laying process lasted for about 193 minutes. The males were also observed to produce very feeble and extremely rare 'ptaak' sounds, which either had pulsatile or non-pulsatile (single pulse) temporal structure. The in-situ observations recorded in the present study can play a significant role in devising effective conservation management plan for the species.

Automated summary

This study provides a description of reproductive behavior and vocalization in Tylototriton himalayanus, a species recently discovered in Eastern India and Nepal. The study shows that courtship and mating in this species occur both during the day and night, with males competing for females in a skewed sex ratio breeding population. The in-situ observations recorded in this study may contribute to conservation management plans for the species.