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| Rineloricaria nudipectoris |
Abstract
A new species of Rineloricaria is described from the Iguaçu, Magé, Saracuruna, Guapiaçu, Macacu, Macaé, and Paraíba do Sul River basins in southeastern Brazil based on morphological and molecular data. The new species is diagnosed among congeners by the combination of the following characters: absence of plates in most of the ventral surface of pectoral girdle; snout tip with elliptical naked area reaching posteriorly the anteriormost pore of the infraorbital ramus of sensory canal; dorsal-fin spinelet present; supraoccipital and predorsal plates with smooth keels; five series of lateral plates below the dorsal fin; median and mid-ventral series of plates with well-developed keels. The new species is distinguished from congeners that inhabit the rivers draining the Serra do Mar in Rio de Janeiro state by the partial plate coverage of the ventral surface of the pectoral girdle and the abdomen (vs. pectoral girdle and abdomen completely covered by plates in Rineloricaria nigricauda, R. steindachneri, and R. zawadzkii). The new species shares the absence of plates on the abdominal surface with other species from the Paraná, Uruguay, and other Brazilian coastal river basins.
Keywords: DNA barcode, Freshwater fishes, Loricariinae, Suckermouth armored catfishes, Integrative taxonomy.
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| Rineloricaria nudipectoris Lateral view of head showing extend of naked skin area (dashed line) of the snout relative to anterior pore (indicated by arrow) on sensory line system in (A) holotype, MNRJ 49345, male, 88.8 mm SL, (B) paratype,MNRJ 43536, female, 97.9 mm SL, and (C) R. zawadzkii,MNRJ 38254, female, 98.7 mm SL. |
Rineloricaria nudipectoris, new species
Diagnosis. Rineloricaria nudipectoris is distinguished from most of its congeners, except for R. aequalicuspis Reis & Cardoso, 2001, R. anhaguapitan Ghazzi, 2008, R. baliola Rodriguez & Reis 2008, R. capitonia Ghazzi, 2008, R. latirostris (Boulenger, 1900), R. maacki Ingenito, Ghazzi, Duboc & Abilhoa, 2008, R. malabarbai Rodriguez & Reis, 2008, R. maquinensis Reis & Cardoso, 2001, R. microlepidogaster (Regan, 1904), R. misionera Rodriguez & Miquelarena, 2005, R. reisi Ghazzi, 2008, R. setepovos Ghazzi, 2008, and R. tropeira Ghazzi, 2008, by the absence of plates in most of the skin of the ventral surface of the pectoral girdle (vs. pectoral girdle completely covered by plates). Rineloricaria nudipectoris is distinguished from R. setepovos by the presence of plates in the abdominal region (Fig. 3) (vs. abdominal region completely naked). It differs from the remaining naked-breast species, except for R. anhaguapitan, R. baliola, and R. capitonia, by its snout having an anterior area of exposed skin without odontodes extended laterally to the most anterior pore of the infraorbital ramus of the sensory canal (vs. naked area of snout not reaching the most anterior pore of infraorbital ramus of sensory canal) (Fig. 4). It is distinguished from R. anhaguapitan and R. capitonia by the upper unbranched caudal-fin ray extending beyond the margin of the fin as a short filament (vs. absence of filamentous extension) and by the leading-edge pectoral-fin ray reaching pelvic-fin origin (vs. leading-edge pectoral-fin ray reaching the first third of the pelvic fin). It differs from R. baliola by the spotted color pattern in the dorsal, pectoral, and pelvic-fin rays (vs. color pattern composed of a dark, wide band covering most of the distal half of the fins).
Etymology. The specific name “nudipectoris” is a compound Latin word formed by the neutral noun pectus, meaning breast, and the adjective nudus, meaning bare, in the genitive declension. Rineloricaria nudipectoris, thus, means Rineloricaria of the naked breast, in reference to the absence of plates in the ventral portion of the pectoral girdle and anterior medial portion of the abdomen.
Geographical distribution. Rineloricaria nudipectoris is known from the Macaé, Macacu, Guapiaçu, Magé, Saracuruna, Iguaçu, and Paraíba do Sul river basins in southeastern Brazil (Fig. 5). Rineloricaria nudipectoris was recorded in sympatry with R. zawadzkii (Costa-Silva et al., 2022)and is associated with running clear waters and sandy or rocky substrates with marginal vegetation.
Eduardo Mejia, Gustavo A. Ferrar and Paulo A. Buckup. 2023. A New Species of Rineloricaria (Siluriformes: Loricariidae) from coastal drainages of Rio de Janeiro, southeastern Brazil. Neotropical Ichthyology. www.ni.bio.br/1982-0224-2022-0083
