I follow Burt and Stirton (1961:37) in treating Diphylla ecaudata as a monotypic species.
Other references to the monotypic genus have consisted only of a listing of the name or of its inclusion in a key.
In all, 27 kinds (subspecies and monotypic species) of the order Megachiroptera are known from the Solomon Islands.
It contains but one monotypic genus, Homo, with its single species, Homo sapiens.
The only endemic for which the geographic history cannot be adequately explained is the monotypic Pityriasis gymnocephala.
Three are monotypic and the fourth has three subspecies, making a total of six taxa.
Most of the species not studied are monotypic and have restricted geographic ranges.
It is easy to see how natural selection can bring about monotypic evolution, but how can it have effected polytypic evolution?
Until more material from critical areas is available for study, I continue to recognize angustapalata as a monotypic species.
It is evident, then, as Romanes claims, that natural selection alone tends to monotypic evolution.
Having a single form or member, especially containing no more than one taxonomic category of the next lower rank. A monotypic genus contains a single species, while a monotypic species consists of a single population that is not divided into subspecies. Compare polytypic.