Parker (1934) distinguished Sphenophryne from other genera of the Genyophryninae (Sphenophryninae in his work) by its pectoral girdle having a more nearly complete complement of bony and cartilaginous elements. Otherwise, the species he placed there were a diverse lot, including ones adapted for climbing, for living in or on leaf litter, or for a cryptic, even burrowing existence. The characteristics of the pectoral girdle are primitive compared to those of other genyophrynine genera, which have reduced or lost one or more of the elements. Thus, the common possession of a primitive girdle is inadequate as the sole character defining the genus. In the present work I review species with the supposedly diagnostic character of Sphenophryne and recognize four genera: Sphenophryne (monotypic), and three removed from synonymy—Austrochaperina (23 species), Liophryne (6 species), and Oxydactyla (5 species). The characters I use to define the genera are for the most part closely tied to the habits of the species and thus are subject to the criticism that homoplasy rather than synapomorphy is demonstrated. Regardless, the probability that the new arrangement identifies four monophyletic lines is considerably greater than that Sphenophryne, as it has been constituted, is monophyletic.
Sphenophryne, Liophryne, and Oxydactyla are confined to New Guinea. Austrochaperina has one species on New Britain, four endemic to northern Australia, one shared between Australia and New Guinea, and 18 on New Guinea and adjacent islands. The genus and species Microbatrachus pusillus, based on a hatchling from the Aru Islands, are considered unidentifiable. Of the 35 species recognized, 17 are described as new and one is removed from synonymy.