Previously, the genus Tainonia was monotypic, accommodating a Hispaniolan pholcid spider originally described as Blechroscelis serripes Simon, 1893. Only 12 adult specimens from six localities had been known. A couple of collecting trips to the Dominican Republic and Haiti resulted in about 200 adult specimens from over 20 localities.

Tainonia spiders are easily distinguished from representatives of the two other pholcid genera on Hispaniola (Modisimus, Micropholcus) by their large size, reaching a leg span of about 16 cm. Morphological and morphometric data strongly support the presence of several species of Tainonia on Hispaniola, but is seems that the increased sampling effort has made it more difficult rather than easier to draw species boundaries. Since most tropical arthropods are known from a single locality, such an uneasy relationship between sampling effort and taxonomic clarity may be a common rather than exceptional phenomenon.