Three genera (i.e. Pseudogyrinocheilus, Parasinilabeo and Semilabeo) are distinct from Rectoris in having a non-crenulated (vs. crenulated) rostral cap and a lower lip anteriorly separated from, but confluent with the lower jaw (vs. anteriorly separated from the lower jaw by a deep groove), and in lacking a frenum that connects the upper jaw and the lower lip (vs. presence). Ptychidio is uniquely characterized by having the ventral margin of the rostral cap split into fimbrillae with branched twigs. This character, together with well-developed mental grooves on the chin and well-developed maxillary barbels, separates this genus from Rectoris, which lacks mental grooves on the chin and with tiny maxillary barbels. Pseudogyrinocheilus, like Akrokolioplax, is similar to Rectoris in having a frenum connecting the upper jaw and the lower lip; this characteristic separates these three genera from all other garrains.