Taxonomic review of the Neotropical genus Gephyrocharax Eigenmann, 1912 (Characiformes, Characidae, Stevardiinae) Author Vanegas-Ríos, James A. text Zootaxa 2016 4100 1 journal volume 10.11646/zootaxa.4100.1.1 98731fd0-8af6-422f-b59e-98c05234dea5 1175-5326 261565 E69BBCC0-775F-4F5C-B125-B890DE0FF7FF Gephyrocharax torresi Vanegas-Ríos, Azpelicueta, Mirande & Gonzales, 2013 ( Figs. 28–29 ) Gephyrocharax torresi Vanegas-Ríos, Azpelicueta, Mirande & Gonzales, 2013 : 276 –280, figs. 1–6 [original description, holotype UIST 1767, type locality: Colombia , Santander, El Carmen, Magdalena River basin, La Colorada River basin, Cascajales River system, Sucio River system, Caño Volador, 6°39'56,44"N 73°34'47,36"W , approximately 338 m a. s. l.]. Thomaz, Arcila , Ortí & Malabarba, 2015 : Add. File 5 [tentative classification]. Diagnosis. Gephyrocharax torresi differs from its congeners (except G. melanocheir ) by the adipose fin absent or vestigial ( vs . adipose fin present) and the fan-shaped structure of adult males, formed on the distal portion of the outermost branched pectoral-fin ray. From most of its congeners it is distinguished by lacking terminal lateral-line tube between caudal-fin rays 10 and 11, except G. melanocheir , G. sinuensis , and G. v a l e n c i a . The whitish area or dark blotch pigmenting the distal portion of the outermost branched pectoral-fin ray of adult males also differentiates G. torresi from almost all its congeners (except G. martae and G. melanocheir ). The species is further distinguished from G. atracaudatus , G. chocoensis , G. intermedius , G. major , and G. venezuelae by the externally developed urogenital papillae ( vs . this papillae not externally developed). The anterior fontanel of adult specimens reduced or extremely absent by the extensive contact between frontals medially differentiates G. torresi from G. caucanus , G. melanocheir , and G. v a l en c i a ( vs . anterior fontanel well developed or, when frontals slightly contacting anterior to epiphyseal bar, forming a medium-sized opening). Gephyrocharax torresi also is distinguished from G. atracaudatus , G. caucanus , G. chocoensis , G. intermedius , G. major , and G. venezuelae by the gill-gland length (6.0–10.3 % SL vs . 0.5–5.4 % SL). Description. This species was recently described by Vanegas-Ríos et al. (2013). FIGURE 28. Gephyrocharax torresi , (A) male, holotype, 36.7 mm SL, UIST 1767; (B) female, paratype, 42.6 mm SL, UIST 1766. White arrow indicates urogenital papillae. Figure modified from Vanegas-Ríos et al . (2013: fig. 1). Distribution. Gephyrocharax torresi is only known from the Sucio River basin (Magdalena basin) in Colombia ( Fig. 1 ). Remarks. During the reexamination of the type series of G. t o r re s i , the absence or fusion of the fourth infraorbital (on both sides of head) present in larger specimens were found in the 60 % of the specimens. This variation was not noticed in the species description (Vanegas-Ríos et al. 2013). The loss of the fourth infraorbital cannot be used as diagnostic of G. torresi at present time, because it needs to be further studied to clarify whether this is intraspecifically variable or not. Nevertheless, it would be recommendable to consider this feature in subsequent comparisons between this species and G. melanocheir . Some specimens from the Topón River in Santander, which is situated at an intermediate locality between the distributional range of G. melanocheir and G. t o r re s i , were identified as the earlier species (ICNMHN, 17777, 17790, 17817, and 17826). These specimens were not analyzed by Vanegas-Ríos et al. (2013) in their comparison of both species. Material examined. All specimens from Colombia , Santander: UIST 1767, holotype of Gephyrocharax torresi , 36.7 mm SL , male, El Carmen, Magdalena River basin, La Colorada River basin, Cascajales River system, Sucio River basin, Caño Volador, 639'56.44"N 7334'47.36"W, approximately 338 m a. s. l. CI-FML 6105 (previously AI 294), 2, 34.0–36.0 mm SL ; MLP 10518 (previously AI 293), 1 c&s paratype , 34.7 mm SL ; UIST 1751, 19, 26.3–37.3 mm SL (1 c&s 36.0 mm SL ), El Carmen, Magdalena River basin, La Colorada River basin, Cascajales River system, Sucio River under bridge to Vereda Islandia , 641'14.6"N 7335'15.10"W, approximately 280 m a. s. l. MLP 10519 (previously AI 295), 2, 35.1–39.0 mm SL ; UIST 1766, 12, 32.0–42.0 mm SL , collected with the holotype .