Taxonomy of the pygmy marmoset (Cebuella Gray, 1866): Geographic variation, species delimitation, and nomenclatural notes

Abstract We examined a recent taxonomic appraisal of Cebuella by Boubli et al. With an increased sample spanning most of the geographic range of the genus, we investigated ventral pelage variation in Cebuella to test the proposition of Boubli et al. that there were three geographically-restricted phenotypes. Additionally, we conducted a model-based species delimitation test using published cytochrome b data and verified the type localities of the available nomina. Contrary to Boubli et al., our analysis showed that ventral pelage of Cebuella varies consistently along geography, indicating the existence of two species-group taxa, not three as suggested by the former authors. The model-based species delimitation also indicated that Cebuella is composed of more than one species. The range of the two species proposed here is different than assumed by previous authors, with one taxon occurring north of middle/lower Rio Solimoes and Rio Napo and the other from south of these rivers. After an extensive literature review, we show that the type locality of Cebuella pygmaea can be reliably restricted to the northern margin of Rio Solimoes. Consequently, the oldest available names for the two species are Cebuella pygmaea for the populations north of middle/lower Rio Solimoes and Rio Napo, and Cebuella niveiventris for the populations south of these rivers.