Direct Development in Eleutherodactylus coqui (Anura: Leptodactylidae): A Staging Table

Abstract

The Puerto Rican frog E. coqui has terrestrial reproduction and direct development, as is the case for all known species of this large, neotropical groups. To facilitate field measurements of embryonic age in E. coqui, a staging table was developed based on changes in the external morphology of embryos. Pre-hatching development was divided into 15 stages. Principal diagnostic features include formation of external gills, progressive pigmentation of the eyes, growth and differentiation of the limbs, development of endolymphatic Ca deposits, expansion of a pigmented body wall, growth of a large, vascularized tail and changes in embryonic behavior. The table was used to stage the eggs of E. antillensis and E. portoricensis, related Puerto Rican species. A literature review suggests that this table may be useful as a general staging scheme for the genus.