Gephyrocharax Eigenmann, 1912

Vanegas-Ríos, James A., 2016, Taxonomic review of the Neotropical genus Gephyrocharax Eigenmann, 1912 (Characiformes, Characidae, Stevardiinae), Zootaxa 4100 (1) : 6-7

Gephyrocharax Eigenmann, 1912

Gephyrocharax Eigenmann, 1912: 23 [type species: Gephyrocharax chocoensis Eigenmann, 1912 by original designation]. Eigenmann, 1914: 41 [listed, key to species, placed in Glandulocaudinae ]. Meek & Hildebrand, 1916: 268, 277 [key to genera, diagnosis]. Eigenmann, 1920a: 11 [placed in Glandulocaudinae ]. Eigenmann, 1922: 100, 155–156 [key to genera, list of species, placed in Glandulocaudinae ]. Eigenmann & Myers, 1929: 463, 464, 467, 477–484 [key to genera, placed in Glandulocaudinae , diagnosis, revision of species (genus revised by Myers)]. Hildebrand, 1938: 252 [diagnosis and revision of Panamanian species]. Fowler, 1940: 71 [placed in Glandulocaudinae ]. Schultz, 1944: 246, 322–326 [diagnosis, key to species, taxonomy of Venezuelan species]. Miles, 1947: 155 –157 [placed in Glandulocaudinae , key to species from Magdalena basin]. Fowler, 1954: 341 [placed in Stevardiidae, Stevardiinae ]. Géry, 1966: 216, 218, 227, 233–235 [placed in Tetragonopterinae , included in key]. Dahl, 1971: 133 –135 [placed in Glandulocaudinae , key to species, listed from Cauca-Magdalena system]. Miles, 1973: 52 –53 [placed in Glandulocaudinae ]. Géry, 1977: 351, 354, 358 [placed in Glandulocaudinae , Glandulocaudini, key to genera, erroneously recorded for Costa Rica]. Weitzman & Fink, 1985: 1, 2, 24, 28–29, 51, 54, 96, 103–104, fig. 17 [placed in Glandulocaudinae , taxonomic comments, compared with Xenurobryconini members, examined material]. Weitzman, Menezes & Weitzman, 1988: 384, 394 [apparently placed in Corynopomini as “other tribes of glandulocaudines”]. Menezes & Weitzman, 1990: 381, fig. 1 [included in phylogeny in “other tribes of glandulocaudines”]. Ortí & Meyer, 1997: 92, fig. 11 [phylogenetic relationships, placed in Glandulocaudinae ]. Weitzman & Menezes, 1998: 172 –174, 186–188, tables 1–3, fig. 1 [classification, phylogenetic relationships, placed in Glandulocaudinae , Corynopomini, comments on morphology]. Castro, Ribeiro, Benine & Melo, 2003: 17, fig. 8 [placed in Glandulocaudinae , Corynopomini]. Malabarba & Weitzman, 2003: 84, 86, 87, fig. 11 [placed in “clade A”, Glandulocaudinae , Corynopomini]. Weitzman, 2003: 224–225 [catalogue of species]. Calcagnotto, Schaefer & DeSalle, 2005: 142, 145, fig. 6 [phylogenetic relationships, placed in Characidae , Glandulocaudinae ]. Weitzman, Menezes, Evers & Burns, 2005: 331, 344–345, fig. 11 [comments on taxonomy, systematic relocation in “clade A”, Stevardiinae (new definition based on kind of secretory cell in caudal organ), Corynopomini]. Menezes & Weitzman, 2009: 298 –299, 302, figs. 1–2 [placed in “clade A”, Stevardiinae , Stevardiini]. Mirande, 2009: 8 [tentative placement in Stevardiinae (new definition similar to “clade A”)]. Javonillo, Malabarba, Weitzman & Burns, 2010: 500, 508–509, table 1, figs. 4–6 [phylogenetic relationships, placed in “clade A” or Stevardiinae , Corynopomini]. Mirande, 2010: 533 –540 [tentative placement in Stevardiinae ]. Oliveira, Avelino, Abe, Mariguela, Benine, Ortí, Vari & Castro, 2011: 16, fig. 12 [phylogenetic relationships, placed in Stevardiinae , positioned in same clade with Corynopoma ]. Tagliacollo, Souza-Lima, Benine & Oliveira, 2012: 302, fig. 2 [phylogeny, placed in Stevardiinae ]. Bonilla-Rivero & López-Rojas, 2013: 487 –495, figs. 1–3 [phylogeography of Venezuelan species]. Thomaz, Arcila, Ortí & Malabarba, 2015: 2, 4, 5, 10, 18, 20, tables 1– 2, figs. 1–2, 5, Add. File 5 [phylogenetic relationships, list of inseminating species, comments on taxonomy, placed in Stevardiinae , Stevardiini]. Gender: masculine.

Corynopomops Fowler, 1943: 6 , fig. 4 [type species: Corynopomops opisthopterus Fowler, 1943 by original designation]. Gender: masculine.

Diagnosis. Gephyrocharax differs from all characids by having the second and third ventral procurrent rays of caudal fin hypertrophied forming a single spur-shaped structure in adult males (vs. rays common or, when modified, forming two spur pointed projections between the second and fourth ventral procurrent rays instead of one). Furthermore, the genus is distinguished from Corynopoma by the caudal peduncle almost as deep as long, its length 6.2–15.6 % SL (vs. elongate, almost twice longer than deep, its length 19.1–22.3 % SL), the presence of adipose fin, except in G. t o r re s i (vs. adipose fin absent), and the absence of a distally-expanded and filamentous structure formed by the posterior border of the opercle, subopercle, and the posteriormost branchiostegal ray in adult males (vs. presence of this structure). Gephyrocharax also differs from Pterobrycon by not having hypertrophied scales as paddle-shaped structures, greatly enlarged posteriorly on the body flanks and located near the humeral region of adult males (vs. scales never hypertrophied, with similar size as scales on body flanks), and by not having a small black or copper-orange spot on the area located dorsal to (or immediately above) the posteriormost anal-fin rays of adult males (vs. presence of this spot).

Distribution. Species of Gephyrocharax are geographically spread across diverse drainages from Panama to Bolivia and in both Cis- and Trans-Andean drainages. In Central America, they occur from coastal drainages of the Gulf of Chiriqui across the Caribbean and Pacific versants to the Palenque River of the Pearl islands. In South America, species of the genus are known from the Atrato, San Juan, León, Cauca-Magdalena, Lake Maracaibo, Ranchería, Orinoco rivers basins, across the Moriquite-Moruga system in the island of Trinidad to the Ucayali, Yuruá, Nanay, Madre de Dios, and Madeira rivers basins in the Amazon system ( Figs. 1–3 ).

Figures

FIGURE 1. Geographic distribution of Trans-Andean species of Gephyrocharax occurring west from eastern versant of Andean Cordillera in northwestern South America to southern Central America.

FIGURE 2. Geographic distribution of Gephyrocharax major, a Cis-Andean species, from Amazon River basin in Bolivia and Peru.

FIGURE 3. Geographic distribution of Gephyrocharax species occurring from eastern versant of Andean Cordillera across Lake Maracaibo and Orinoco basins to island of Trinidad in northeast South America. Map includes additional records reported by Bonilla-Rivero & López-Rojas (1997) and Bonilla-Rivero & López-Rojas (2001) for G. valencia (MBUCV 297, 3023, 3029, 3051, 35679, and 35682; Cúpira, Las Peñas de Taría, and Urama Rivers basin, not catalogued) and G. venezuelae (MBUCV 35685, 35686, and 35687).