Redescription of stenostygnus pusio simon and synonymy of caribbiantinae with stenostygninae (Opiliones: Laniatores, Biantidae)

Based on the lack of the tarsal process and genitalic features, Stenostygnus pusio Simon 1879 is transferred from the Stygnidae to the Biantidae. This is the first record of the family Biantidae from Brazil, Colombia and Ecuador. The subfamily Caribbiantinae is synonymized with Stenostygninae. Genera and species other than Stenostygnus pusio, formerly placed in the Stenostygninae are transferred to Heterostygninae (Stygnidae). The convergences between Stygnidae and Biantidae are presented and discussed.