Cheilonimata, Provenzano-Rizzi, 2023

Provenzano-Rizzi, Francisco, 2023, A new genus and species of whiptail armored catfish (Siluriformes: Loricariinae) from southern Venezuela, Zootaxa 5315 (4), pp. 315-328 : 317-318

Cheilonimata new genus

Type-species. Cheilonimata minuta new species by original designation.

Includes. Cheilonimata minuta new species. Rhadinoloricaria papillosa Crispim-Rodrigues, Bernt, Waltz, Silva, Benine, Oliveira, Covain, and Roxo 2023 . Cheilonimata papillosa ( Crispim-Rodrigues, Bernt, Waltz, Silva, Benine, Oliveira, Covain, and Roxo 2023) new combination.

Diagnosis. The new genus Cheilonimata is included in the subfamily Loricariinae , tribe Loricariini , Pseudohemiodon group ( Covain et al. 2016; Roxo et al. 2019; Londoño-Burbano & Reis 2021). Species of the Pseudohemiodon group share the following external characters: head and body very depressed, especially the caudal peduncle; caudal-fin with ten branched rays; maxillary barbel usually reaches or surpasses gill opening or pectoral-fin origin; 16 or fewer teeth in each mandible, teeth small or very small, in some cases an edentulous upper jaw; lip surfaces with papillae and/or barblets; lip borders with barblets branched or not; oral cavity with barblets, mostly on palate; post-orbital notch small and abdomen surface from totally plated to partially plated or naked.

Cheilonimata n. gen. can be recognized among all genera of the subfamily Loricariinae , including those belonging to the Loricaria and Pseudohemiodon groups by the presence of two unique and distinctive buccal characters: 1) Presence of translucent membrane that contain and interconnects the unbranched barblets found on upper lip border and on maxillary barbel, leaving only the tips of the barblets free vs. barblets found on upper lip border and on maxillary barbel free, without the interconnecting translucent membrane or in some cases, a very narrow translucent membrane at base of the barblets, never as described for Cheilonimata . 2) Lower lip surface with cylindrical, lengthened and unbranched barblets, some of them surpassing the posterior lower lip margin vs. lower lip surface with papillae or with papillae and barblets, some species may have lower lip with a thick pad of musculature.

Further distinguished from all species of the Pseudohemiodon group, except C. papillosa by lower lip margin with unbranched barblets and without protuberances vs. lower lip margin with branched barblets or with small protuberances, in some cases. From all species of the Pseudohemiodon group except species of Pseudohemiodon and C. papillosa (except the holotype) by palate behind premaxillaries at midline, with one elongated, cylindrical, unbranched, fleshy barblet vs. two (one just anterior the other) elongated, cylindrical, unbranched, fleshy barblets, or with one thick barblet, ramified into three or four conical arms, similarly or variable sized, or with six or seven elongated, branched and unbranched barblets. From Apistoloricaria condei , A. laani , C. papillosa , Crossoloricaria bahuaja , Planiloricaria cryptodon , Rhadinoloricaria listrorhinos , R. macromystax , R. ommation and R. stewarti by maxillary barbel only reaches pectoral-fin origin vs. maxillary barbel surpasses pectoral-fin base. From Dentectus barbarmatus and Pyxiloricaria menezesi by maxillary barbel reaches pectoral-fin origin vs. maxillary barbel not surpassing gill opening. Also distinguishable from D. barbarmatus by maxillary barbel surface without plates, barblets on upper lip margin not covering the mouth opening and upper jaw teeth visible to naked eye vs. maxillary barbel surface with plates, barblets on upper lip margin lengthened to cover the mouth opening and upper jaw teeth very small, hard to observe to naked eyes. From P. cryptodon by upper jaw teeth present vs. upper jaw teeth absent. From P. menezesi by head contour not triangular and without fleshy flap on branchiostegal membrane vs. head contour triangular and with fleshy flap covering branchiostegal membrane. From R. macromystax and R. stewarti by snout not projected and spatula-shape vs. snout projected and spatula shape.

Etymology. Cheilonimata is derived from the Greek, “Χείλος ” Cheilos meaning lip and “νημάτια ” nimátia or nimata meaning threads or filaments, alluding to the cylindrical, elongated, unbranched and fleshy barblets observed over lower lip surface. Gender feminine.