Pareiorhaphis Miranda Ribeiro, 1918

Pareiorhaphis Miranda Ribeiro, 1918: 106.

Type species: Hemipsilichthys calmoni (= Psilichthys cameroni Steindachner, 1907). Type species by subsequent designation by Regan (1920: 14). Gender: feminine. Subsequent type species designation by Gosline (1947: 102) of Hemipsilichthys duseni is invalid.

Diagnosis. Pareiorhaphis is diagnosed among loricariids by having the following synapomorphies. (1) Cheeks (postrostral and cheek plates) covered with hypertrophied odontodes in nuptial males. This character is shared with delturines, Isbrueckerichthys duseni, and some loricariines and hypostomines. (2) Opercle with hypertrophied odontodes in nuptial males. Present in all Pareiorhaphis and shared with Hemipsilichthys and some loricariines. (3) Exposed lateral process of cleithum with hypertrophied odontodes in nuptial males. Present in all Pareiorhaphis species and shared with Hemipsilichthys gobio and H. papillatus and some loricariines. (4) Lateroventral portion of preopercle deeply rugose due to the implantation of hypertrophied odontodes in nuptial males. Present in all Pareiorhaphis species and shared with H. gobio and H. papillatus. The characters shared with the groups above are most parsimoniously interpreted as independently derived according to the discussion of relationships in Armbruster (2004) and Reis et al. (2006).

The following characters are also useful to distinguish Pareiorhaphis species from the remaining neoplecostomines. Abdomen naked or with small embedded platelets and lower lip without a series of distinct papillae behind the dentaries (vs abdomen with plates forming a central polygonal path and lower lip with a series of distinct papillae behind the dentaries in Neoplecostomus); infraorbital series of plates forming the lateral edge on the nasal opening and dorsal-fin spinelet usually present (vs infraorbital series of plates not forming the lateral edge of the nasal opening and dorsal-fin spinelet absent in Isbrueckerichthys); adipose fin present (vs absent in Pareiorhina); tooth series in dentary straight or slightly curved and odontodes on ventral surface of pelvicfin spine aligned with the spine axis (vs tooth series in dentary approximately U-shaped and odontodes on ventral surface of pelvic-fin spine turned medially in Kronichthys).