DIRECT DEVELOPMENT IN DESMOGNATHUS-AENEUS (CAUDATA, PLETHODONTIDAE) -A STAGING TABLE

We describe development of the salamander Desmognathus aeneus (Plethod ontidae: Desmognathinae) from fertilization to hatching. Embryonic dev elopment is divided into 33 stages on the basis of external morphology . Front- and hind-limb buds appear nearly simultaneously. This feature is characteristic of desmognathines, as well as direct-developing ple thodontids (e.g., Ensatina and Batruchoseps), Previous workers have ch aracterized the developmental mode of D. aeneus as intermediate betwee n larval and direct development. Based on features of the embryo and h atchling, we contend that D. aeneus is a true direct developer, First, prominent endolymphatic calcium deposits are present during embryonic development, a feature thought to be correlated with direct developme nt in salamanders and frogs, Second, D. aeneus shows no evidence of a desmognathine larval pigment pattern during development. Third, hatchl ings have eyelids, nasolabial grooves, tiny gill stubs that disappear soon after hatching, an adult color pattern, and no tail fin. These fe atures are characteristic of hatchling of other direct-developing plet hodontids, Fourth, the skull and hyobranchial apparatus are essentiall y adult in morphology. The initial characterization of D. aeneus as '' semimetamorphosed'' probably was based on hatchlings that were induced to hatch prematurely in the lab.