A Comparative Normal Table of Anuran Development: Towards a Unified Framework for Xenopus and Non-Model Species

Background Developmental staging tables, primarily defined by specific external morphological characteristics, are fundamental tools in amphibian research. Although numerous staging tables have been reported for various frog species, significant differences are often observed, especially when compared to the canonical model organism Xenopus. To date, no comprehensive study has integrated Xenopus developmental stages with the other widely used anuran staging systems, such as the Gosner table. Results To bridge this gap, we present the first comparative staging system that directly aligns the Xenopus developmental table with two widely used non-model anuran staging systems. This integrated framework was validated through detailed morphological observations across the entire embryonic development of three representative species—Xenopus laevis/tropicalis, Microhyla fissipes, and Odorrana tormota—each exemplifying a major staging paradigm. Our system comprehensively covers both early embryonic and postembryonic developmental stages. Conclusions This integrated system provides a unified foundation for analyzing morphological development in anurans. It is expected to facilitate cross-species comparisons and promote interdisciplinary research in areas such as ecotoxicology, evolutionary developmental biology, and conservation physiology.