Larval development and breeding ecology of Ziegler's crocodile newt, Tylototriton ziegleri Nishikawa, Matsui and Nguyen, 2013 (Caudata: Salamandridae), compared to other Tylototriton representatives
We describe for the first time the larval development and stages of the recently described Ziegler's Crocodile Newt (Tylototriton ziegleri), an endemic species to northern Vietnam. Diagnostic morphological characters are provided for Grosse (1997, 2013) stages 27-32, 35-36, and 44-45, as well as comparisons with larval stages of other Tylototriton representatives. In addition, natural history data and an ecological assessment of the breeding niche are presented for T. ziegleri as well as for T. vietnamensis, from whom the former species was only recently taxonomically separated. We provide data extending the known breeding season of these two cryptic species in the North of Vietnam, which in fact lasts from April until July. On average, the clutches of T. ziegleri consisted of 67 +/- 32 eggs, were found on rock and soil substrates with a distance of 50 +/- 28 cm from water, whereas the clutches of T. vietnamensis were significantly smaller (43 +/- 19 eggs), found only on soil and were further distant from water (80 +/- 41 cm). The known maximum altitudinal distribution of T. vietnamensis is herein increased to 980 m above sea level. Based on the examples of T. ziegleri and T. vietnamensis, this study highlights how important it is to uncover cryptic species, define their exact distribution range, and investigate potential differences in ecological adaptations in order to assess the conservation status, develop proper conservation planning and provide suitable conditions for potential ex situ breeding programs
