The First Comprehensive Description of the Normal Development of Annandale's High Altitude Frog, Kurixalus naso (Annandale, 1912)

Abstract: The discrimination of developmental stages of anurans is of critical importance in understanding the morphological characteristics of each specific stage of tadpoles. Unlike most rhacophorids which construct foam nest during egg deposition, Kurixalus naso shows no foam formation during oviposition. This rhacophorid displays a unique oviposition whereby the eggs are laid in the moist soil under burrows and mixed with the loose top layer of the soil giving those eggs a seed-like appearance. The present study highlighted and documented the developmental stages of Kurixalus naso until complete metamorphosis. A normal developmental table consisting of 46 developmental stages was proposed for Kurixalus naso. Stages of development and metamorphosis of Kurixalus naso were divided into 11 major developmental terms, each consisting of a number of successive stages: fertilization (stages 1–2), cleavage-blastula (stages 3–9), gastrula (stages 10–12), neurula (stages 13–16), tail bud stages (stages 17–20), external gill stages (stages 21–22), operculum and oral disc stages (stages 23–25), hind limb bud formation (stages 26–30), toe differentiation and development (stages 31–39), well-developed hind limb (stages 40–41) and metamorphosis (stages 42–46). The embryos of this species hatched into a free-swimming tadpole at stage 25. Kurixalus naso completed the entire process of development and metamorphosis over 62 days. This investigation may contribute to future studies on evaluation of adaptive characters, comparative embryology, and other developmental studies, associated with phylogenetic inferences.