Sternopygus embera Torgersen, Galindo-Cuervo, Ortega-Lara, Lujan, Reis, & Albert, new species Figs. 1, 2, 3A, 4A, 5A, 6, 8A, Tab. 2 Sternopygus macrurus (not Bloch & Schneider)— Hulen et al., 2005:408–409, 425 (reference to trans-Andean Pacific slope populations based on examination of NRM 27740); Torgersen & Albert, 2022:724 (same as previous); Torgersen et al., 2023:3 (same as previous); Maldonado-Ocampo, 2011: fig. 24 (S. “ macrurus ” from the Río San Juan). Holotype. CZUT-IC 28654 (ex. ROM 111084), 326 mm TL (264 mm LEA), Colombia, Departamento Chocó, Río Baudó at muddy beach downstream of Puerto Meluk, 5°12'35.9"N, 76°57'16.3"W, July 22, 2019, Y.D.M. Asprilla, J.L.P. Cuella, N.K. Lujan, A. Ortega-Lara, D.F.M. Ramos, & V. Meza-Vargas. Paratypes. All from Colombia. Río Baudó basin. CZUT-IC 21284, (4 measured of 7), 84–381 mm TL (63–317 mm LEA), Departamento Chocó, Río Baudó, 5°12'35.9"N, 76°57'16.3"W, August 4, 2019, A. Ortega-Lara, N.K. Lujan, & J. Poveda; FMNH 70508, (1), 171 mm TL (138 mm LEA), Departamento Chocó, Pizarro, 4°57'24.8"N, 77°21'13.7"W, September 1945, K. von Sneidern; ICN-MHN 107 (1 measured of 2), 189 mm TL (155 mm LEA), Departamento Chocó, Río Baudó. Pavarandó, 5°26'32.7"N, 76°57'16.6"W, November 1, 1959, G. Dahl; ICN-MHN 108 (2), 314–323 mm TL (259–274 mm LEA), Departamento Chocó, Río Baudó, 5°26'32.7"N, 76°57'16.6"W, November 1, 1959, G. Dahl; ICN-MHN176 (1 measured of 23), 187 mm TL (154 mm LEA), Departamento Chocó, Río Baudó, 4°41'11.566"N, 76°55'47.578"W, November 4, 1959, G. Dahl; NRM 27740, (4), 229–263 mm TL (178–254 mm LEA), Departamento Chocó, Boca de Pepé, 5°04'0.1"N, 77°03'00.0"W, February 22, 1989, S.O. Kullander, & A.M.C. Silfvergrip; ROM 111049, (1), 295 mm TL (238 mm LEA), Departamento Chocó, Caño Membá downstream of Puerto Meluk, 5°10'48.7"N, 76°59'29.8"W, July 22, 2019, Y.D.M. Asprilla, J.L.P. Cuella, N.K. Lujan, A. Ortega-Lara, D.F.M. Ramos, & V.M. Vargas; ROM 111084, (1), 243 mm TL (196 mm LEA), collected with holotype. Río San Juan basin. FMNH 56798, (1), 266 mm TL (228 mm LEA), Departamento Valle del Cauca, creek near mouth of Río Calima, 4°08'51.4"N, 77°08'45.2"W, 1913, A.W. Henn; FMNH 56799, (2), 207–251 mm TL (174–214 mm LEA), Departamento Valle del Cauca, creek tributary to Río Calima near Boca del Guineo, 4°04'26.7"N, 77°03'0.4"W, 1913, A.W. Henn; FMNH 105216, (1 measured of 2), 102 mm TL (85 mm LEA), Departamento Valle del Cauca, creek near mouth of Río Calima, 4°08'51.4"N, 77°08'46.4"W, 1913, A.W. Henn; IMCN 906, (1), 297 mm TL (248 mm LEA), Departamento Valle del Cauca, Río San Juan, 4°10'05.3"N, 77°18'09.0"W, April 6, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 907, (3), 304–339 mm TL (247–281 mm LEA), Departamento Valle del Cauca, Río San Juan, Buenaventura, 4°10'05.3"N, 77°18'09.0"W, May 1, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 908, (3), 260–299 mm TL (211–239 mm LEA), Departamento Valle del Cauca, Río San Juan, 4°13'18.1"N, 77°13'21.5"W, May 8, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 910, (1), 341 mm TL (298 mm LEA), Departamento Valle del Cauca, Río San Juan, 4°10'05.3"N, 77°18'09.0"W, May 5, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 911, (3), 242–309 mm TL (193–255 mm LEA), Departamento Valle del Cauca, Río San Juan, 4°13'46.2"N, 77°21'36.1"W, May 8, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 918, (1), 231 mm TL (205 mm LEA), Departamento Valle del Cauca, Río San Juan, 4°10'05.3"N, 77°18'09.0"W, May 8, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 955, (8), 191–481 mm TL (151–442 mm LEA), Departamento Valle del Cauca, Río San Juan Basin, 4°10'05.3"N, 77°18'09.0"W, April 6, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 961, (4 measured of 7), 154–215 mm TL (124–174 mm LEA), Departamento Valle del Cauca, Río San Juan Basin, 4°10'05.3"N, 77°18'09.0"W, May 8, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 1038, (1), 212 mm TL (174 mm LEA), Departamento Chocó, Río San Juan Basin, caño Llenagua, 4°10'05.3"N, 77°18'09.0"W, July 8, 2002, T. Silirío et al.; IMCN 1045, (2), 286–347 mm TL (242–297 mm LEA), Departamento Valle del Cauca, Río San Juan Basin, 4°10'05.3"N, 77°18'09.0"W, July 7, 2002, T. Silirío et al.; IMCN 1193, (1), 298 mm TL (241 mm LEA), Departamento Valle del Cauca, Río San Juan Basin, 4°10'05.3"N, 77°18'09.0"W, April 6, 2002. P. Pizario et al.; IMCN 1330 (1 measured of 2), 455 mm TL (396 mm LEA), Departamento Chocó, Río San Juan, 4°10'06.7"N, 77°30'51.9"W, July13, 2003, T. Silirío; IMCN 1334 (1), 232mm TL (187 mm LEA), Departamento Chocó, Río San Juan Basin, caño Pepepan, 4°13'37.8"N, 77°16'06.0"W, August 16, 2002, P. Pizario et al.; IMCN 1376 (1), 256 mm TL (216 mm LEA), Departamento Chocó, Río San Juan Basin, caño Cuellar, 4°13'37.8"N, 77°16'06.0"W, August 16, 2002, P. Pizario et al.; IMCN 1431 (2), 271–376 mm TL (227–308 mm LEA), Departamento Chocó, Río Patechuco, 4°13'37.8"N, 77°16'06.0"W, November 23, 2002, T. Silirío et al.; IMCN 1618 (1 measured of 6), 334 mm TL (287 mm LEA), Departamento Chocó, Río San Juan Basin, caño Llano, 4°14'52.8"N, 77°15'21.6"W, October 31, 2002, P. Pizario et al.; IMCN 1676 (6), 296–397 mm TL (238–253 mm LEA), Departamento Chocó, Río San Juan Basin, 4°10'05.3"N, 77°18'09.0"W, October 31, 2002, P. Pizario et al.; IMCN 1685 (6), 243–309 mm TL (196–266 mm LEA), Departamento Chocó, caño Media, 4°14'53.1"N, 77°14'11.7"W, June 3, 2002, P. Pizario et al.; IMCN1696 (1), 244 mm TL (196 mm LEA), Departamento Valle del Cauca, caño Dopurma, 4°13'29.1"N, 77°15'48.7"W, June 3, 2002, P. Pizario et al.; IMCN 1787 (2), 312–332 mm TL (255–271 mm LEA), Departamento Chocó, caño Checho, 4°09'50.1"N, 77°29'47.0"W, August 31, 2002, P. Pizario et al.; IMCN 1802 (1), 229 mm TL (183 mm LEA), Departamento Chocó, Río San Juan, 4°13'18.1"N, 77°13'21.5"W, June 3, 2002, P. Pizario et al.; IMCN 1883, (1 measured of 10), 305 mm TL 256 mm LEA), Departamento Chocó, caño Limoncito, 4°14'12.4"N, 77°16'51.1"W, June 1, 2002, P. Pizario et al.; IMCN 1896, (1 measured of 10), 252 mm TL (218 mm LEA), Departamento Chocó, caño Pisabarro, 4°11'09.5"N, 77°22'26.1"W, February 2, 2002, P. Pizario et al.; IMCN 1911, (6), 184–363 mm TL (143–316 mm LEA), Río San Juan Basin, Chocó, 4°10'05.3"N, 77°18'09.0"W, August 23, 2002, P. Pizario et al.; IMCN 1935, (1), 242 mm TL (197 mm LEA), Departamento Chocó, caño Cuellar, 4°13'18.1"N, 77°13'21.5"W, March 31, 2002, P. Pizario et al.; IMCN 1959, (1), 277 mm TL (226 mm LEA), Departamento Valle del Cauca, Río San Juan, 4°10'05.3"N, 77°18'09.0"W, June 2, 2003, P. Pizario et al.; IMCN 2011, (1), 253 mm TL (215 mm LEA), between Departamento Chocó and Departamento Valle del Cauca, caño Wegueral, May 31, 2003, P. Pizario et al.; IMCN 2020, (1), 234 mm TL (202 mm LEA), Departamento Chocó, Puerto Pizario, caño Pepepan, 4°13'37.8"N, 77°16'06.0"W, May 31, 2002, P. Pizario et al.; IMCN 2027, (2), 268–382 mm TL (219–301 mm LEA), Departamento Chocó, Buenaventura, Río San Juan, 4°13'18.1"N, 77°18'09.0"W, May 7, 2002, P. Pizario et al.; IMCN 2076, (2), 329–335 mm TL (262–273 mm LEA), Departamento Chocó, caño Cuellar, 4°13'18.1"N, 77°13'21.5"W, July 13, 2003, A. Ortega-Lara; IMCN 2078, (2), 252–267 mm TL (203–229 mm LEA), Departamento Chocó, Río San Juan, 4°10'05.3"N, 77°18'09.0"W, July 13, 2003, A. Ortega-Lara; IMCN 2082, (1), 319 mm TL (262 mm LEA), Departamento Valle del Cauca, caño Dopurma, 4°13'30"N, 77°15'50.399"W, June 2, 2002, P. Pizario et al.; IMCN 2083, (1), 235 mm TL (206 mm LEA), Departamento Valle del Cauca, Río San Juan Basin, 4°10'05.3"N, 77°15'48.7"W, June 2, 2002, P. Pizario et al.; IMCN 2116, (3), 241–336 mm TL (192–274 mm LEA), Departamento Chocó, caño Nalde, 4°11'14.7"N, 77°24'32.4"W, August 13, 2003, T. Silirío; IMCN 2120, (3), 244– 255 mm TL (198–206 mm LEA), Departamento Chocó, caño Cuellar, 4°13'18.1"N, 77°13'21.5"W, September 13, 2003, P. Pizario et al.; IMCN 2174, (3), 280–302 mm TL (227–251 mm LEA), Departamento Valle del Cauca, Puerto Piziario, caño Pepepan, 4°13'37.8"N, 77°16'06.0"W, July 13, 2002, P. Pizario et al.; IMCN 2202, (4), 209– 264 mm TL (170–194 mm LEA), Departamento Chocó, caño Media, 4°14'53.1"N, 77°14'11.7"W, July 22, 2003, P. Pizario et al.; ROM 106345, (1), 327 mm TL (264 mm LEA), Departamento Valle del Cauca, Bajo Río Calima, Buenaventura, 3°59'06.8"N, 76°45'35.5"W, July 31, 2017, C. Conde-Saldaña, N.K. Lujan, V. Meza-Vargas, A. Ortega-Lara, & G.C. Sanchez; FMNH 70884, (3), 127–172 mm TL (98–128 mm LEA), Departamento Chocó, Río San Juan at Pangala, about 40 km N of Palestina, 4°14'15.0"N, 77°01'03.0"W, January 14, 1971, B. Malkin, & P. Burchard; FMNH 56800, (1 measured of 2), 372 mm TL (297 mm LEA), Departamento Chocó, Río San Juan at mouth of Río Munguido, 4°11'09.0"N 77°00'58"W, 1913, A.W. Henn; ICN-MHN 210 (2), 223–248 TL (196–209 mm LEA), Departamento Chocó, Río San Juan, 4°45'3.031"N, 76°51'15.598"W. October 24, 1959, G. Dahl; IMCN 1601 (1 measured of 4), 210 mm TL (184 mm LEA), Departamento Chocó, Istmina, caño Llenagua, 4°42'21.8"N, 76°53'49.8"W, January 17, 2002, P. Pizario et al.; IMCN 1832, (9 measured of 10), 174–321 mm TL (135–268 mm LEA), Departamento Chocó, caño Oro, 4°42'21.8"N, 76°53'49.8"W, June 1, 2002, T. Silirío et al.; IMCN 1938, (1), 291 mm TL (235 mm LEA), Departamento Chocó, Buenaventura, caño Alejando, 4°34'22.9"N, 76°58'16.3"W, January 18, 2003, P. Pizario et al.; IMCN 2084, (1), 267 mm TL (226 mm LEA), Departamento Valle del Cauca, Río San Juan Basin, Pacifico, 4°44'59.1"N, 76°51'34.0"W, June 3, 2002, A. Ortega-Lara; IMCN 2239, (2), 257–262 mm TL (203–212 mm LEA), Departamento Chocó, Río San Juan, 4°34'22.9"N, 76°58'16.3"W, July 22, 2003, P. Pizario et al.; IMCN 2132, (1), 306 mm TL (251 mm LEA), Departamento Chocó, Río San Juan, 4°34'22.9"N, 76°58'15.6"W, August 24, 2003, P. Pizario et al.; FMNH 56797, (1), 270 mm TL (230 mm LEA), Departamento Chocó, Istmina, 5°9'17.3"N, 76°41'59.9"W, March 18, 1912, C.H. Eigenmann; FMNH 69646, (2 measured of 4), 120–156 mm TL (116–143 mm LEA), Departamento Chocó, Istmina, 5°09'17.3"N, 76°41'59.9"W, March 18, 1912, C.H. Eigenmann; IMCN 905, (2), 249–382 mm TL (219–335 mm LEA), Departamento Chocó, caño Patecucho, 5°09'00.0"N, 76°40'12.0"W, June 1, 2002, S. Usma, L. Meza, B. Arias, W. Arias, & C. Araque; IMCN 1999, (1), 276 mm TL (242 mm LEA), Departamento Chocó, Istmina, caño Patecucho, 5°09'00.0"N, 76°40'12.0"W, May 31, 2003, P. Pizario et al.; USNM 79236, (1), 200 mm TL (161 mm LEA), Departamento Chocó, Istmina, 5°09'17.3"N, 76°41'59.9"W, March 18, 1912, C.H. Eigenmann. Non-Type. STRI 2135, (1), 202 mm TL (178 mm LEA), Departamento Chocó, Río San Juan, 4°13'12.0"N, 77°12'00.0"W, February 1, 1994, STRI team. Diagnosis. Sternopygus embera is diagnosed from all congeners by the distal tip of the second parapophysis of the Weberian apparatus extending more laterally than the fourth parapophysis in dorsal and ventral view (vs. fourth parapophysis extending laterally beyond second parapophysis; see Description). Sternopygus embera differs from S. sabaji, S. xingu, and all members of the S. aequilabiatus group in having a shorter head length (10.9–14 % vs 13.4–19.6%), a convex anterior margin of the neurocranium in adult specimens (vs. concave), and ascending endopterygoid process nearly vertical along its ontogeny (vs. strongly angled posteriorly in adults). The new species differs from S. astrabes, S. branco, S. macrurus, S. sabaji, S. sarae, and S. xingu by the complete lack of a humeral spot (Fig. 1; vs. humeral spot either faintly present with poorly defined margins or darkly pigmented and well-defined). Sternopygus embera further differs from S. astrabes, S. obtusirostris, S. sabaji, and S. sarae by the lack of any pigmented bars or saddles in its ontogeny. Sternopygus embera differs from S. branco, S. macrurus, S. sarae, and S. xingu in having fewer precaudal vertebrae (22–23 vs. 24–29 PCV) and in having more precaudal vertebrae than S. astrabes (18–19 PCV). Sternopygus embera further differs from S. sabaji by the possession of 11–16 endopterygoid teeth (vs. teeth absent). Description. Head and body shape in Fig. 1, morphometric and meristic data in Tab. 2, cephalic mechanosensory line and pore configuration in Fig. 2. Species of small/intermediate size with maximum recorded total length of 481 mm. Body elongate, and compressed laterally in body cavity region, more laterally compressed in post-coelomic body region; body widest immediately behind head; entire body covered in axially-elongate ovoid cycloid scales, except head and fins. Caudal appendage cylindrical in cross section. Lateral line complete and non-interrupted, extending onto tail posterior to last anal-fin ray. Pale-colored longitudinal stripe present over pterygiophore bases. Eye small and circular, not covered by layer of skin. Anterior nares slightly tubular, posterior nares non-tubular. Total of 13–16 pectoral-fin rays, 208–272 anal-fin rays, all unbranched, and 22–23 precaudal vertebrae. Neurocranium. Osteology of mature specimen (254 mm LEA) in dorsal, lateral, and ventral views in Fig. 3A. Dorsal margin convex in lateral view along its entire extent from tip of mesethmoid to posterior margin of parietal. Preorbital region of neurocranium rounded and slightly decurved in lateral view, parasphenoid ventral margin slightly concave in lateral view anterior to basipterygoid process (sensu Arratia, 2013: fig. 48), or parasphenoid lateral wing (sensu Adriaens & Verraes, 1998: fig. 19b). Neurocranium relatively well-ossified compared to other gymnotiforms, with all bones of braincase ossified to their peripheral margins, and with little or no intervening cartilaginous plates. Supraorbital laterosensory canal bone fused to frontal. Lateral ethmoid large and well ossified, its ventral margin extending lateral to vomer in curved blade-like shape. Sphenotic small, lateral process extending beyond lateral neurocranium margin. All bones of ethmoid (e.g., lateral ethmoid, ventral ethmoid) and sphenoid (e.g., parasphenoid, pterosphenoid, orbitosphenoid) regions relatively well ossified compared to congeners.Anterior and posterior cranial fontanelles large and of approximately equal length, separated by interorbital bridge, posterior fontanel extending posteriorly to about vertical with anterior margin of exoccipital. Antorbital and postorbital processes of frontal robust, anterior process tapering to distal tip. Parasphenoid anterior portion slightly wider than posterior portion; parasphenoid ventral margin mostly flat and without longitudinal ridges on lateral margins. Oral jaws and opercular series. Fig. 4A. Mouth terminal. Premaxilla ovoid in frontal view, triangular in dorsal and ventral views, with 5–6 unevenly arranged tooth rows, with approximately 43–52 large, straight conical teeth. Maxilla broad, strongly curved. Dentary dentition “brush-shaped” (sensu Mago-Leccia, 1978), with approximately 66–108 mostly recurved teeth arranged in 5–6 irregular rows near mental symphysis tapering laterally to single tooth at posterolateral margin of tooth field. Retroarticular blocky, not articulating directly with quadrate and without anterior ascending process. All elements of suspensorium well-ossified except autopalatine. Hyomandibula broad with two large foramina on dorsomedial surface and four foramina on lateral, anterior, posterior, and ventral margins for passage of rami of facial, trigeminal, and lateral-line nerves. Symplectic well-ossified, long thin tapering to blunt point at antero-ventral margin, nested in notch of quadrate ventroposterior process. Quadrate well-ossified, fanshaped, with broad contact with endopterygoid; its ventroposterior process extending past quadrate ascending blade. Metapterygoid well-ossified, articulating with endopterygoid. Endopterygoid broad and robust with 11–16 teeth in two rows on ventral surface; endopterygoid ascending process mostly straight, connected by thin ligament to ventral surface of frontal. Autopalatine unossified. All components of opercular series well ossified. Preopercle broad, Jshaped with six large bony arches to permit passage of infraorbital laterosensory canals. Opercle approximately triangular with rounded margins, broad lamella on dorsal margin, and ridges on dorsal and ventral portions of bone. Weberian apparatus. Comprising anterior four vertebrae and their articulating elements (Fig. 5A). Vertebral centra increasing in size posteriorly, both in diameter and axial extent. V1 approximately half width and thickness of V4. Parapophysis of V2 (2nd parapophysis) expanded laterally tapering to distal margin. Os suspensorium anterior margins well separated, posterior margins meeting at point on ventral midline. Intercalarium narrow, less than axial thickness of V1. Tripus sickle-shaped, its anterior margin broadly contacting intercalarium across its entire extent. Its posterior margin tapering thin and curving towards midline of V4. Lateral process of 4th parapophysis articulating with rib anteriorly oriented, not extending laterally further than lateral process of 2nd parapophysis. Scaphium cup-shaped, angled towards center. Supraneural robust and slightly curved, its dorsal limb oriented vertically. Neural spine of fourth arch robust, tapering distally to acute point, strongly angled dorsally so as becoming nearly horizontal, extending beyond V4 approximately width of V4. Color in life. With distinct live color pattern also common in other trans-Andean species of S. aequilabiatus group (Fig. 6). Head and back a low-intensity iridescent yellow-green, with grayish-purple coloration below lateral line. No humeral spot. Pale yellow or cream-colored longitudinal stripe extending along posterior third of body along line of contact between hypaxial and anal-fin pterygiophore muscles.Anal fin membrane hyaline to transparent with darkly pigmented anal-fin rays. Color in alcohol. Almost uniformly light orange-brown to yellow (Fig. 1). Longitudinal cream stripe often still evident. No humeral spot. Distribution. Sternopygus embera is known from the Río Baudó and Río San Juan Pacific slope basins of the Chocó and Valle del Cauca departments of Colombia (Fig. 7). and Methods. ......continued on the next page Sexual dimorphism. The gonads of several specimens were examined via dissection. No obvious sexual dimorphism was documented during morphometric and osteological observations of the specimens. Etymology. The specific epithet honors the Emberá, an Indigenous people native to the Chocó region of western Colombia, where the new species occurs. The name acknowledges the deep connection of the Emberá people with the region’s rivers and ecosystems. A noun in apposition. Ecology. Sternopygus embera has been collected in the deltas and main channels of the Río Baudó and Río San Juan and their tributaries, reaching elevations up to 980 m above sea level. This species is commonly encountered in shallow waters, usually less than 2 m in depth, and inhabits both clear and turbid environments. The highest abundance of adult specimens recorded between 1996 and 2003 occurred from May to September, with a peak in June and July, coinciding with the local dry season and period of most intensive fieldwork. This apparent peak in abundance likely reflects increased sampling effort during the dry season, as ichthyological expeditions are less frequent during the rainy months. Habitats from which the species has been collected typically have substrates composed of stones, sand, and submerged woody debris. Riverbanks are generally lined with shrubby vegetation and riparian forest. However, near coastal areas, individuals have also been collected from transitional zones where freshwater and saltwater mix, often associated with mangrove vegetation.

Published as part of Torgersen, Kevin T., Galindo-Cuervo, Aleidy M., Ortega-Lara, Armando, Lujan, Nathan K., Reis, Roberto E. & Albert, James S., 2026, Towards deconstruction of the Sternopygus macrurus species complex (Gymnotiformes: Sternopygidae): description of a new species from the Pacific Coast of Colombia, pp. 539-560 in Zootaxa 5748 (4) on pages 543-551, DOI: 10.11646/zootaxa.5748.4.5, http://zenodo.org/record/20292864