Tocantinsia, MEES, 1974

GENUS TOCANTINSIA MEES, 1974 View in CoL

Tocantinsia Mees, 1974: 108 View in CoL (type species: Tocantinsia depressa Mees, 1974 View in CoL ; type by original designation. Gender feminine. Subsequent to the description of the genus, Mees (1984) proposed the synonymization of its type species with Glanidium piresi View in CoL Miranda Ribeiro, 1920, still recognizing the genus Tocantinsia View in CoL as valid).

Included species: Tocantinsia piresi View in CoL (Miranda Ribeiro, 1920).

Diagnosis: Tocantinsia is diagnosed by 13 molecular and five morphological synapomorphies. Non-exclusive: (1) Medial portion of dentary dorsally arched on symphysis (char. 3607: 0 → 1), convergent in Asterophysus ; (2) upper gill rakers moderate in size, approximately half length of gill filaments (char. 3638: 1 → 0), convergent in Ageneiosini (except Tympanopleura cryptica ), Glanidium (except Glanidium cesarpintoi ), Gephyromochlus and Pseudauchenipterus ; (3) serration on anterior margin of pectoral-fin spine truncated (char. 3704: 0 → 1), convergent in Ageneiosini , Auchenipterus fordicei , Glanidium ribeiroi , Tatia intermedia and Trachelyopterus coriaceus ; (4) last proximal radial of anal fin laminar (char. 3741: 0 → 1), convergent in Ageneiosus (except Ageneiosus inermis , Ageneiosus militaris and Ageneiosus lineatus ), Tympanopleura rondoni , Tympanopleura cryptica , Auchenipterus and Auchenipterichthys ; and (5) caudal fin bifurcated (char. 3746: 1 → 0), convergent in Centromochlinae , Auchenipterini (except Epapterus ), Tympanopleura , Ageneiosus (except Ageneiosus inermis , Ageneiosus vittatus ).

Comparisons: Tocantinsia is a predator species comprising individuals of relatively large size, robust, frequently serving as a source of food in local communities along the Tocantins drainage. It is easily distinguished from remaining auchenipterids, except Asterophysus , by having the medial portion of the dentary dorsally arched on the symphysis (vs. dentary straight); and from auchenipterines, except Auchenipterini (apart from Epapterus ), Asterophysus , Tympanopleura and Ageneiosus (apart from Ageneiosus inermis and Ageneiosus vittatus ), by having the caudal fin bifurcated (vs. caudal fin truncated). It differs from auchenipterines, except Trachycorystes , Spinipterus and Liosomadoras , by the posterior process of the epioccipital being pointed and very short, with a wide base formed by the lateral border of the epioccipital (vs. epioccipital forming a simple spine, bifurcated or laminar) and, except for Asterophysus , by having the dorsal profile of the head posteriorly to the eye flat and straight (vs. head posteriorly arched or with some level of curvature). It is further distinguished from Asterophysus by having the dorsal-fin origin posteriorly displaced relative to the pectoral-fin origin, at a distance approximately equivalent to the length of the dorsal-fin spine (vs. dorsal-fin origin approximately at a vertical line from the pectoral-fin origin), posterior process of post-temporal supracleithrum surpassing the vertical line from the dorsal-fin origin (vs. posterior process of post-temporal suprachleitrum not reaching the vertical line from the dorsal-fin origin), and the mouth gape reaching the eye, but never surpassing it (vs. end of mouth gape far surpassing the eye).