The scincid genus Tropidophorus is diagnosed by a suite of derived morphological characters, one of which is newly recognized: the corners of the eyelid form within one scale instead of between two. This character occurs elsewhere only in the distantly related Cophoscincopus and may be related to semiaquatic habits of both taxa. For Tropidophorus, we also report a novel arrangement of supraciliary scales in some species, which is potentially useful in inferring intrageneric relationships; a deeply bifurcated hemipenis, confirming the taxon as a member of the Sphenomorphus group of lygosomine skinks; further details of the taxonomic and sexual occurrence of postanal pores in the genus, and the presence of a pale iris, which contrasts with the dark iris of most other members of the Sphenomorphus group. We also note patterns of endemism in the genus and an unusual disjunction in the distribution.