Chrysobrycon calamar Vanegas-Ríos & Urbano-Bonilla & Sánchez-Garcés 2024, sp. nov.
Creators: name: Vanegas-Ríos, James Anyelo
name: Urbano-Bonilla, Alexander
name: Sánchez-Garcés, Gian Carlo
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Characiformes
Characidae
Chrysobrycon
Chrysobrycon calamar

description: Chrysobrycon calamar sp. nov.
Figs 1, 2, 3, 4, 5, 6, Table 1, Suppl. material 1: F – G
Type material.
Holotype. MPUJ 18618, male, 39.3 mm SL, COLOMBIA, Guaviare department, San José del Guaviare, upper Río Vaupés, Calamar, Río Unilla, Caño Toño; 2 ° 09 ' 50 " N, 72 ° 50 ' 16 " W, c. 250 m a. s. l., Maldonado-Ocampo JA, Prada-Pedreros S, Moreno-Arias C, Zamudio JE, Cubides F, & Urbano-Bonilla A leg.; 5 Jan. 2017.
Paratypes. All from COLOMBIA, Guaviare department, San José del Guaviare, upper Río Vaupés: ICN-MHN 24743, 3, 31.4–37.7 mm SL; Calamar, Chiribiquete National Natural Park, Río Unilla, Caño Salado; 1 ° 59 ' 20 " N, 72 ° 53 ' 22 " W, c. 270 m a. s. l.; Maldonado-Ocampo JA, Prada-Pedreros S, Moreno-Arias C, Zamudio JE, Cubides F, & Urbano-Bonilla A leg.; 7 Jan. 2017. MLP-Ict 11733, 2, 34.6–36.5 mm SL; El Retorno, Río Unilla; 2 ° 11 ' 51 " N, 72 ° 44 ' 59 " W, c. 250 m a. s. l.; Maldonado-Ocampo JA, Prada-Pedreros S, Moreno-Arias C, Zamudio JE, Cubides F. & Urbano-Bonilla A leg.; 3 Jan. 2017. MPUJ 12850, 3, 32.9–36.9 mm SL, Calamar, Chiribiquete National Natural Park, Raudal del Río Itilla; 1 ° 59 ' 30 " N, 72 ° 53 ' 15 " W, c. 260 m a. s. l.; Maldonado-Ocampo JA, Prada-Pedreros S, Moreno-Arias C, Zamudio JE, Cubides F, & Urbano-Bonilla A leg.; 7 Jan. 2017. MPUJ 12965, 3, 34.8–41.2 mm SL; Calamar, Chiribiquete National Natural Park, Río Unilla, Caño Salado; 1 ° 59 ' 20 " N, 72 ° 53 ' 22 " W, c. 270 m a. s. l.; Maldonado-Ocampo JA, Prada-Pedreros S, Moreno-Arias C, Zamudio JE, Cubides F, & Urbano-Bonilla A leg.; 7 Jan. 2017. MPUJ 12966, 8 (2 c & s, 35.7–35.8 mm SL), 33.2–40.9 mm SL; same data as for holotype. MPUJ 12967, 7, 31.1–39.4 mm SL; Calamar, Río Unilla, Caño La Tigra; 2 ° 10 ' 57 " N, 72 ° 50 ' 16 " W; c. 250 m a. s. l., Maldonado-Ocampo JA, Prada-Pedreros S, Moreno-Arias C, Zamudio JE, Cubides F, & Urbano-Bonilla A leg.; 4 Jun. 2017. MPUJ 12969, 3, 33.2–37.2 mm SL, El Retorno, Río Unilla; 2 ° 11 ' 51 " N, 72 ° 44 ' 59 " W, c. 250 m a. s. l.; Maldonado-Ocampo JA, Prada-Pedreros S, Moreno-Arias C, Zamudio JE, Cubides F, & Urbano-Bonilla A leg.; 3 Jan 2017.
Diagnosis.
Chrysobrycon calamar differs from its congeners by the following combined characters: a distinctive dark vertical blotch placed laterally on the abdominal flanks in adult males, just immediately dorsal to the urogenital region (vs. this pigmentation weak, diffuse, poorly developed, or if well-defined, more developed longitudinally than vertically, never forming a distinctive vertical blotch); a well-developed vertically humeral blotch in adult males (almost rectangular-shaped, see additional details in sexual dimorphism section vs. scarcely expanded vertically, somewhat irregular, or circular-shaped mark); the possession of numerous (two to 12) tiny bony hooks on nearly all the upper lobe caudal-fin rays in adult males (vs. hooks confined to the lower lobe caudal-fin rays, except in C. guahibo, C. hesperus, and C. mojicai, with hooks arranged in a set of one to three hooks on a single ray), the number of vertebrae (43 vs. 38–42); the posterior portion of the maxilla not reaching the vertical through the anterior border of the eye when the mouth is closed, except from C. yoliae (vs. this portion reaching or surpassing the vertical through the anterior border of eye); an elongated maxillary anterior process, representing proportionally 40 % or more of the total length of the bone (vs. with a shorter maxillary anterior process, representing less than 40 % of its length); and the presence of bony hooks in adult males on nearly all the branched anal-fin rays, except C. hesperus (vs. bony hooks restricted up to the anterior half of fin or not extending to the posteriormost rays).
The presence of a simple terminal lateral-line tube between the caudal-fin rays 11 and 12 (v. tube absent) distinguishes C. calamar from C. hesperus and C. myersi. Additionally, C. calamar is also distinguished from C. myersi by the number of circumpeduncular scales (13–14 vs. 17–19), distance between dorsal- and adipose-fin origins (20.4–24.4 % SL vs. 28.2–33.5 % SL), dorsal-fin to caudal-fin base (33.0–39.6 % SL vs. 40.1–47.4 % SL), eye to dorsal-fin origin (51.9–57.2 % SL vs. 45.8–49.2 % SL), and upper jaw length (38.1–45.5 % HL vs. 48.9–54.9 % HL), and from C. hesperus by the maximum number of cusps on the maxillary teeth (tricuspid vs. pentacuspid) and number of supraneurals (11 vs. 12–14). The number of dentary teeth differentiates C. calamar from C. mojicai and C. yoliae (13–17 vs. 20–27). Furthermore, C. calamar is also distinguished from C. mojicai by the number of radii on the lateral-line scales (5–9 vs. 11–18), number of maxillary teeth (2–4 vs. 9–17), and shape of the distal tips of most maxillary teeth (straight along their lengths vs. lateroventrally curved), and from C. yoliae by the body depth at dorsal-fin origin (27.5–33.5 % SL vs. 34.4–42.2 % SL), and distance between dorsal- and adipose-fin origins (20.4–24.4 % SL vs. 26.8–28.8 % SL).
Description.
Morphometric data in Table 1. Largest male 41.2 mm SL, largest female 35.8 mm SL. Body laterally compressed, maximum depth at vertical through area immediately anterior to anal-fin origins (Fig. 1). Dorsal profile of body: straight from tip of premaxilla to posterior region of head; slightly convex from posterior end of supraoccipital area to dorsal-fin origin; straight and slanting ventrally from first dorsal-fin ray to caudal peduncle. Dorsal profile of caudal peduncle straight. Ventral profile of body convex from tip of snout to pelvic-fin origin, slightly convex between pelvic- and anal-fin origins, straight and slanting dorsally from this point to caudal peduncle. Belly with like keel-shaped area between pelvic-fin origin and urogenital pore, consisting of one row of four to six scales forming sharp edge. Ventral profile of caudal peduncle straight. Head with anterior region acute. Frontal fontanel absent. Epiphyseal branch of supraorbital canal absent. Anterior nostril round, separated by skin fold from posterior nostril; posterior nostril opening considerably larger than anterior one. Two well-developed pit organs along grooves in head; anterior groove round, between nasal bone and nostril; posterior groove larger, extended along entire frontal, and covered with rows of neuromasts.
Mouth superior, lower jaw projecting slightly anterior to upper jaw. Premaxillary teeth arranged in two rows (Fig. 2). Outer row with four (5), five (22), or six * (3) tricuspid teeth. Inner row with four (1) or five * (29) teeth; symphyseal tooth tetracuspid; contiguous teeth pentacuspid; and posteriormost tooth conical to pentacuspid. Maxilla not fully toothed, with two (1), three * (23), or four (6) teeth tricuspid, sometimes conical. Maxillary teeth straight along their lengths, not distally curved lateroventrally. Maxilla short, with elongated anterior process, and extending on point at vertical between nostrils and anterior margin of orbit, but never reaching anterior margin of eye when mouth closed and body horizontally straight. Dentary moderately toothed, with 13 (3), 14 (12), 15 * (6), 16 (5), or 17 (4) teeth; three anteriormost teeth large, pentacuspid (rarely tetracuspid); one median-sized tooth tri to pentacuspid, followed by 9 (3), 10 (12), 11 * (6), 12 (5), or 13 (4) smaller conical or biscupid posterior teeth (Fig. 2).
Dorsal-fin rays ii (30), 8 * (28), or 9 (2). Nine proximal dorsal-fin pterygiophores (2 c & s). Dorsal-fin origin at vertical between anal-fin rays 10 and 13. Adipose-fin origin at vertical crossing the second scale posterior to anal-fin termination. Anal-fin rays iv (6) or v * (24), 24 (1), 25 (1), 26 (8), 27 * (6), 28 (8), or 29 (6). Twenty-seven to 29 proximal pterygiophores in anal fin (2 c & s). Anal-fin origin at posterior half of body, always anterior to vertical through dorsal-fin origin. Pectoral-fin rays i, 9 (17), or 10 * (13), last ray usually simple but counted as branched. Pectoral-fin distal tip reaching or surpassing one-half of pelvic-fin length (Fig. 1). Pelvic-fin rays i, 7 * in all specimens; last ray simple but counted as branched. Pelvic-fin origin slightly anterior to half of body. Caudal fin forked with 10 / 9 principal rays in all specimens.
Scales cycloid, with six to nine radii along posterior field, circuli on anterior, dorsal, and ventral fields, surpassing one-half scale length. Lateral line completely pored: 42 (8), 43 * (8), 44 (11), 45 (2), or 46 (1). Terminal lateral-line tube present on caudal-fin interradial membrane. Predorsal scales 21 (1), 22 * (13), 23 (14), or 24 (2) forming nearly continuous row. Scale rows between dorsal fin and lateral line five (24) or six * (6). Five * (28) or six (2) scale rows between lateral line and anal fin. Four (1) or five * (29) scale rows between lateral line and pelvic fin. Circumpeduncular scales 13 (1) or 14 * (29). One row of 13 (1), 14 (1), 15 (4), 16 (5), 17 (9), 18 * (7), or 19 (3) scales forming sheath along anal-fin base. Total number of vertebrae 43 (2 c & s), 17 precaudal, and 26 caudal. Six * (27), or seven (3) gill rakers on upper arm of first branchial arch; lower arm with 11 (11), 12 * (14), or 13 (5).
Color in alcohol.
Ground color pale yellow in preserved males and females, moderately darker dorsally. Dark chromatophores on all body, in minor proportion in ventral region, forming dark brown narrow band along mid-dorsal line, often diffuse. Humeral blotch dark, widely developed vertically, forming a rectangular-shaped pattern in most specimens (Fig. 1); frequently less developed vertically or somewhat rounded in female specimens. Dark black midlateral stripe extending from vertical through pelvic-fin origin to caudal peduncle. Wider lateral band of dark brown chromatophores located dorsal and ventral to this black stripe, less intense but more dorsoventrally developed, especially toward lateral line, and usually forming somewhat oval-shaped blotch from last portion of caudal peduncle, crossing interradialis muscles, to middle caudal-fin rays. Dark chromatophores forming stripes between myomeres ventrally located to midlateral stripe on posterior half of body. Dorsal fin mostly hyaline, with dark chromatophores mainly distributed on interradial membranes. Adipose fin mostly hyaline, with few dark chromatophores. Anal fin somewhat dusky, with dark chromatophores extending over interradial membranes, more concentrated on base and distal portions of fin. Caudal fin mostly hyaline, with dark chromatophores extending mainly on interracial membranes and borders of rays; middle caudal-fin rays slightly pigmented with dark chromatophores. Pectoral and pelvic fins mostly hyaline with scarce dark chromatophores, but pectoral fins slightly more pigmented by having chromatophores on borders of rays. Head darker dorsally and light yellow ventrally, except for intense dark pigmentation on anterior region to isthmus. Dark chromatophores concentrated on premaxilla, maxilla, and lower jaw. Opercle dusky, with dark chromatophores intensely concentrated, especially on posterior region. Infraorbitals light yellow with scattered dark chromatophores (first infraorbital usually less pigmented).
Color in life.
Based on adult male specimens photographed (Fig. 3). Ground color pale yellow dorsally and white or whitish yellow ventrally, being darker on mid-flanks. Dark chromatophores on all body, with abdominal region lighter below lateral line. Head yellowish orange dorsally but silvery laterally, with scattered dark chromatophores. Well-defined dark humeral blotch expanded vertically. Dark black midlateral stripe extending from vertical through pelvic-fin origin to caudal peduncle. Red half-moon shaped spot situated dorsally on pupil. Snout slightly bright yellow anteriorly. Wider lateral band of dark chromatophores located dorsal and ventral to this black stripe, usually forming somewhat oval-shaped blotch from last portion of caudal peduncle, crossing interradialis muscles, to middle caudal-fin rays. Dark blotch vertically expanded on abdominal flanks, located dorsally to urogenital region and anterior to first anal-fin rays. Pectoral and pelvic fins somewhat hyaline. Dorsal fin somewhat dusky. Orange adipose fin. Anal fin somewhat dusky, especially on base and distal tips of rays, but with yellowish-orange pigmentation in middle region of first anterior rays. Caudal fin somewhat yellowish orange on outer rays.
Sexual dimorphism.
Adult males differ from females by the presence of bony hooks on the caudal-, pelvic-, and anal-fin rays. The caudal fin of males has four to 32 short, slender antrorse hooks that are usually paired (one or two pairs per segment) and placed on the dorsal margin of the lower caudal-fin rays 11 to 17. Additionally, two to 12 unpaired (sometimes paired) tiny antrorse hooks are placed on the ventral margin of the caudal-fin rays 2 to 10. All pelvic-fin rays of males bear slender antrorse hooks positioned lateroventrally along most rays length (on their margins) and are much more numerous and longer on the segmented and branched portions of each one (usually grouped in two pairs per segment). The anal fin of males has four to 30 variable-sized hooks distributed in one or two pairs per segment along the posteriormost simple ray and on all the branched rays; from the fifth to 10 th branched anal-fin rays, the bony hooks are discontinuously arranged along the rays’ length, clearly forming two separated groups of hooks (one closer to the base and another nearer the distal portion). The anal-fin bony hooks placed closer to the base are more lateroventrally oriented in comparison with the hooks distributed on the distal portion. From the eighth or ninth anal-fin ray, the bony hooks are much more restricted to the distal portions, gradually decreasing in size anteroposteriorly.
The lower caudal-fin lobe of adult males has a broadly open pocket consisting of a single pouch scale and at least three accessory scales (Fig. 4). The pouch scale is relatively small, elongate, curved, and slightly folded laterally on its posterior portion; its hypertrophied radii are ventrally arranged at an obtuse angle, almost perpendicular to the caudal-fin rays. Underneath the pouch scale is located a medial accessory scale of similar shape, which is usually indistinguishable in lateral view. Lateral to the pouch scale, there are two accessory scales that largely outline the outermost margin of the pocket opening. One of them is curved and elongated, forming mainly the laterodorsal face of the pocket (its border with radii is almost completely concave). This laterodorsal accessory scale is independent from the pouch scale, but both are strongly attached to each other dorsally through a well-developed medial mass of connective tissue. The other accessory scale is extended between the previous ones but is not displaced posteroventrally, and for this reason, its radii are almost parallel to the horizontal axis of the body. The posterior border of this accessory scale delineates almost the entire lateroventral region of the pocket opening. A small scale laterally placed on the lateroventral accessory scale often closes the ventral margin of the pocket over the caudal-fin ray 19.
The gill gland of males is relatively long, formed by the fusion of the anterior 17 (3), 18 (4), 19 * (5), 20 (2), or 22 (2) gill filaments of the ventral arm of the first gill arch. The gill-gland length ranged between 7.8 and 10.4 % SL (mean = 9.0 % ± 0.7, n = 15). Adult males have the anal-fin distal margin slightly straight or convex, whereas in females it is slightly concave.
The scale rows forming a sharp region between the pelvic-fin origin and urogenital pore are covered by dark chromatophores in both sexes, but the area is more intensely pigmented in adult males. The anal-fin distal margin of adult males is convex, whereas in females it is straight. Additionally, adult males are distinguished from females by possessing an irregular dark blotch vertically extended on the dorsal region between the anus and third anal-fin ray, reaching up to three or four scale rows of height and expanding up to three or four scales longitudinally (Fig. 1; Suppl. material 1: fig. S 1 F – G). Both types of pigmentations were observed to be dark or black in live or alcohol-preserved specimens (Figs 1, 2). In adult males, the oval-shaped caudal peduncle blotch is incompletely developed horizontally by the presence of a less intense or clearer area on the region associated with the hypertrophied caudal-fin squamation. The humeral mark was observed to be more greatly developed vertically in adult males, but it was less developed vertically in most females, being somewhat rounded.
Distribution.
Chrysobrycon calamar is known from several streams flowing into the upper portion of the Vaupés basin in Colombia (Fig. 5; Suppl. materials 2, 3).
Etymology.
The species is named “ calamar ” in reference to Calamar, a municipality in the department of Guaviare, which is part of its type locality. This is treated as a noun in apposition. Despite the fact that the municipality was the epicenter of slavery for the Carijona and Witoto indigenous people in the rubber era (1879 and 1912) and the Second World War (1942 and 1945), in addition to processes of colonization, extraction of natural resources, introduction of illicit crops, subversion, and paramilitarism (Arcila et al. 1999), it is currently a peaceful territory.
Ecological notes.
Chrysobrycon calamar inhabits the main tributaries of the upper Vaupés (Río Itilla and Río Unilla basins) and associated drainages (Fig. 5; Suppl. materials 2, 3) between 250 and 270 m of altitude. It is generally found in shallow, clear, black water (<1 m) with moderate flow over sand, pebbles, and rocks. In the rapids of the Río Itilla, the water has a temperature of 25.7 ° C with high concentrations of dissolved oxygen (7.99 mg / l), a slightly acidic pH (6.5), and a low conductivity of 14.0 µS / cm. The gastrointestinal content of two samples examined (MPUJ 12966) mainly evidences a high consumption of aquatic and terrestrial invertebrates (remains of Diptera, Lepidoptera, Formicidae). The new species was collected in syntopy with other characids such as Aphyocharax pusillus (Günther, 1869), Charax tectifer (Cope, 1870), Moenkhausia oligolepis (Günther, 1864), M. comma Eigenmann, 1908, Brachychalcinus copei (Steindachner, 1882), Jupiaba abramoides (Eigenmann, 1909), Hyphessobrycon agulha Fowler, 1913, and Hemigrammus yinyang Lima & Sousa, 2009, Tyttocharax sp. and Phenacogaster sp.
Remarks.
Comparing the morphometric and meristic data between the specimens from the Río Vaupés and Río Putumayo basins, no discrete differences were observed between the ranges obtained. However, the specimens from the Río Putumayo basin are slightly larger than those from the Río Vaupés basin (34.2–44.4 % SL, mean = 41.4 % SL vs. 33.2–41.2 % SL, mean = 35.5 % SL). Across the PCA comparing the specimens of both basins, the first four components (which accounted for 64.4 % of the total variance) were chosen as consensus between the scree plot method and broken-stick model (Suppl. materials 4, 5). In the plots obtained (Fig. 6 A, B), the individuals of both basins did not separate in shape. In fact, we observed that the females and males from the Vaupés and Putumayo basins also overlapped each other slightly in the plots. The measures that most influenced the first four components were the snout to dorsal-fin origin (PC 1: - 0.6), dorsal fin to caudal-fin base (PC 2: 0.4), dorsal-fin length (PC 2: 0.4), pelvic-fin length (PC 3: - 0.3), and pectoral-fin length (PC 4: - 0.3) (Suppl. material 6). The specimens from the Río Putumayo basin shared almost completely the diagnostic characteristics of the new species. However, we observed that the dark blotch on the abdominal flanks is slightly more developed laterally to the urogenital region than dorsally, and the number of maxillary teeth is slightly greater (3–7, mode = 6 vs. 2–4, mode = 3). In addition, we did not have enough well-preserved adult males to observe in more detail the variation associated with this pigmentation. For these reasons, we treat this population as C. aff. calamar and are cautious in this regard, pending further specimens or DNA samples that can become available to conduct additional comparisons. We hope this population can be reanalyzed in the future as part of the ongoing revision of the genus that the first author performs in the Amazon basin.Key to the species ofChrysobrycon(modified from Vanegas-Ríos and Urbano-Bonilla, 2017)
Comparative material examined
Chrysobrycon eliasi. All from PERU, Madre de Dios department, Tambopata: MUSM 39970, holotype, 34.3 mm SL; Madre de Dios basin, Loboyoc creek; 12 ° 27 ' 07 " S, 69 ° 7 ' 43 " W, c. 210 m a. s. l. MLP-Ict 10831, 3 paratypes, 33.0– 43.5 mm SL (2 c & s specimens 33.0– 39.9 mm SL); Río Manuripe basin, creek at km 50; 12 ° 11 ' 21 " S, 69 ° 6 ' 57 " W, c. 250 m a. s. l.; CI-FML 6153, 2 paratypes, 37.3–37.6 mm SL, Río Manuripe basin, Yarinal creek; 12 ° 3 ' 06 " S, 69 ° 4 ' 50 " W, c. 250 m a. s. l.; MUSM 39971, 14 paratypes, 26.1–40.8 mm SL; same data as for holotype. MUSM 39972, 8 paratypes, 28.0– 43.2 mm SL; Manuripe basin, creek at km 50; 12 ° 11 ' 21 " S, 69 ° 6 ' 5 " W; c. 250 m a. s. l.; MUSM 39973, 2 paratypes, 36.11–37.63 mm SL; Río Madre de Dios basin, Loboyoc creek; 12 ° 27 ' 21 " S, 69 ° 7 ' 42 " W, c. 230 m a. s. l.; MUSM 39974, 3 paratypes, 29.3–41.2 mm SL, San Antonio, Río Heath basin, San Antonio creek; 12 ° 41 ' 03 " S, 68 ° 43 ' 09 " W, c. 190 m a. s. l. ROM 66378, 4, 27.6–31.6 mm SL; Tambopata, La Colpa, lodge, Río Tambopata, stream at left bank at 2.1 km. Chrysobrycon aff. calamar. All from COLOMBIA, Río Putumayo basin: MLP-Ict 11734, 5, 34.1–44.4 mm SL; Valle del Guamuez municipality, Río Cohembí. MLP-Ict 11735, 2, 42.4–43.9 mm SL; Puerto Asís municipality, Quebrada Tuayá. MPUJ 18619, 1, male. 34.2 mm SL; Putumayo, Puerto Asís municipality, Quebrada NN 4. Chrysobrycon guahibo. All from COLOMBIA, Meta department, Río Orinoco basin, Río Guaviare basin, Río Ariari basin: MPUJ 7160, holotype, 31.9 mm SL; Fuente de Oro municipality, Caño Abrote; 3 ° 17 ' 39 " N, 73 ° 32 ' 02 " W, 260 m a. s. l. All are paratypes, Puerto Lleras municipality, Caño Cunimia; 3 ° 11 ' 24 " N, 73 ° 39 ' 39 " W, c. 270 m: CI-FML 6152, 6, 26.5–33.6 mm SL; MLP-Ict 10829, 2 c & s specimens, 30.4–31.3 mm SL; MPUJ 7162, 11, 26.7–29.0 mm SL; MLP-Ict 10830, 4, 28.9–31.3 mm SL. All are paratypes: MPUJ 7161, 10, 23.0– 29.6 mm SL, same data as for holotype. MPUJ 7163, 1, 31.0 mm SL; Puerto Lleras municipality, Caño Cunimia; 3 ° 11 ' 24 " N, 73 ° 39 ' 39 " W, c. 270 m a. s. l. MPUJ 7164, 3, 31.0– 34.8 mm SL; Puerto Lleras municipality, Caño Cunimia; 3 ° 11 ' 24 " N, 73 ° 39 ' 39 " W, c. 270 m a. s. l. MPUJ 7165, 6, 28.7–35.3 mm SL; San Juan de Arama municipality, Caño Casa Roja; 3 ° 22 ' 25 " N, 73 ° 52 ' 13 " W, c. 450 m a. s. l. MPUJ 7166, 8, 31.3–36.6 mm SL; Vista Hermosa municipality, Caño Uricacha; 3 ° 16 ' 56 " N, 73 ° 36 ' 45 " W, c. 270 m a. s. l. MPUJ 7167, 10, 29.0– 35.2 mm SL; Fuente de Oro municipality, Caño Abrote; 3 ° 17 ' 39 " N, 73 ° 32 ' 02 " W, c. 250 m a. s. l. MPUJ 7168, 2, 43.5–44.6 mm SL; Vista Hermosa municipality, Caño Guapaya, 3 ° 2 ' 59 " N, 73 ° 49 ' 17 " W, c. 290 m a. s. l. Chrysobrycon hesperus. All from ECUADOR: All from Napo-Pastaza provinces, upper Río Villano near Villano, Río Napo system: ANSP 75912, 1 paratype, 77.4 mm SL; ANSP 79513, 1 paratype, 67.4 mm SL. All from Napo-Pastaza provinces, Río Pucuno, tributary of Río Suno, Pucuno enters of Suno: USNM 164056, holotype of Hysteronotus hesperus, 72.3 mm SL (radiographed); USNM 175124, 1 paratype, 59.1 mm SL (radiographed). ANSP 75914, 1 paratype, 63.2 mm SL; Napo-Pastaza provinces, Río Suno near mouth, tributary upper Río Napo. ANSP 79159, 2 paratypes, 60.3–76.0 mm SL; Río Pucuno, a tributary of Río Suno, upper Río Napo system. USNM 164042, 1 paratype, 70.5 mm SL; Napo-Pastaza provinces, Río Villano, upper Río Curaray, near Villano. FMNH 94557, 2 *, 49.3–68.4; Napo, Río Arajuno, Quebrada to Río Gusano [Cusano], joins Río Gusano [Cusano] about 100 m upstream from mouth; [c. 1 ° 05 ' 25 " S, 77 ° 32 ' 46 " W, 420 m a. s. l.]. All from PERU, Loreto department: MUSM 26607, 2, 59.9–66.1 mm SL; Andoas, upper Amazon basin, Río Corrientes basin, Caballo creek, 2 ° 33 ' 41 " S, 76 ° 13 ' 45 " W, c. 210 m a. s. l. MUSM 26617, 2, 29.8–33.1 mm SL, upper Amazon basin, Río Corrientes, drainage flowing into Huayuri creek; 2 ° 35 ' 51 " S, 76 ° 13 ' 53 " W, c. 210 m a. s. l. MUSM 28640, 2, 25.5–27.0 mm SL; Forestal creek, Río Corrientes basin, 2 ° 19 ' 14 " S, 76 ° 10 ' 31 " W, c. 220 m a. s. l. MUSM 28665, 3, 36.2–54.6 mm SL (1 c & s specimen, 54.6 mm SL); Andoas, upper Amazon basin, Río Corrientes basin, Forestal creek; 2 ° 21 ' 28 " S, 76 ° 9 ' 25 " W, c. 240 m a. s. l. MUSM 28682, 3, 41.6–46.1 mm SL, Andoas, upper Amazon basin, San Carlos creek, flowing into Río Manchari; 2 ° 24 ' 35 " S, 76 ° 6 ' 36 " W, c. 200 m a. s. l. MUSM 32124, 1, 27.1 mm SL, Andoas, upper Amazon basin, Río Corrientes basin, Río Platanoyacu; 3 ° 8 ' 27 " S, 75 ° 45 ' 09 " W; c. 150 m a. s. l. MUSM 33159, 2, 29.3–43.9 mm SL, Andoas, upper Amazon basin, Río Pastaza, Carmen creek; 2 ° 22 ' 44 " S, 76 ° 9 ' 44 " W, c. 220 m a. s. l. Chrysobrycon myersi. All from PERU: Huanuco department, small creek directly tributary to Río Pachitea (itself tributary to Río Ucayali) at the northeastern outskirts of Tournavista; ANSP 112325, 2 paratypes, 30.1–46.1 mm SL; ANSP 112326, 3 paratypes, 28.3–32.0 mm SL; USNM 203697, holotype of Hysteronotus myersi, 46.5 mm SL; USNM 203698, 6 paratypes, 24.9–31.3 mm SL (1 radiographed, 31.3 mm SL). LACM 37720.4, 3, 34.3–63.8 mm SL, Pasco department, Iscozacin Valley, Pan de Azúcar, stream about 100 yards above entrance into Río Iscozacin. MUSM 12040, 1, 29.7 mm SL, Cusco department, La Convención province, Echarate, Urubamba basin, Río Picha, Cocha Kamariampiveni; c. 11 ° 36 ' 00 " S, 73 ° 05 ' 00 " W, 380 m a. s. l. MUSM 18908, 2, 42.4–48.6 mm SL; Pasco department, Oxapampa province, Puerto Bermudez, Río Pachitea basin, Atas creek; c. 10 ° 17 ' 47 " S, 74 ° 56 ' 11 " W, 260 m a. s. l. MUSM 36068, 1, 31.6 mm SL, Curso department, La Convencion province, Echarate, Río Urubamba basin, Río Parotori system, Río Poyiriari; 12 ° 10 ' 44 " S, 73 ° 5 ' 06 " W, c. 540 m a. s. l. MUSM 36084, 3, 37.1–58.7 mm SL, Cusco department, La Convención province, Echarate, Urubamba basin, Río Parotori system, Río Poyriari; 12 ° 10 ' 45 " S, 73 ° 5 ' 18 " W, c. 590 m a. s. l. MUSM 36109, 2, 32.8–36.3 mm SL, Cusco department, La Convención province, Echarate, Río Urubamba, Río Parotori, Río Poyiriari, Piriabindeni creek; 12 ° 1 ' 13 " S, 73 ° 0 ' 24 " W, c. 590 m a. s. l. MUSM 36125, 3, 29.2–38.6 mm SL, Cusco department, La Convención province, Echarate, Río Parotori basin, Piriabindeni creek; 12 ° 1 ' 19 " S, 73 ° 4 ' 15 " W, c. 550 m a. s. l. MUSM 37889, 2, 45.1–51.0 mm SL, Junin department, Satipo province, Mashira, Río Tambo basin, Capirosankari creek; 11 ° 1 ' 25 " S, 73 ° 33 ' 36 " W, c. 420 m a. s. l. MUSM 37933, 3, 58.0– 60.8 mm SL, Cusco department, La Convención province, Echarate, Kinterani, Naca-naca creek; 11 ° 28 ' 09 " S, 73 ° 18 ' 02 " W, c. 420 m a. s. l. MUSM 38671, 3, 50.9–60.7 mm SL (1 c & s specimen, 58.6 mm SL), Junin department, Satipo province, Río Tambo basin, Pukakunga creek; 73 ° 28 ' 02 " W, 11 ° 24 ' 37 " S, c. 590 m a. s. l. Chrysobrycon mojicai. All from COLOMBIA, Amazonas department, Río Amazon basin, Leticia: IAvH-P 13932, holotype, 50.6 mm SL; Amacayacu National Natural Park, unnamed forest stream tributary of Río Mata-Matá; 3 ° 48 ' 23 " S, 70 ° 15 ' 58 " W, c. 90 m a. s. l. All are paratypes: IAvH-P 8291, 5, 25.0– 50.4 mm SL (one c & s specimen, 50.4 mm SL), same data as for the holotype. IAvH-P 8295, 9, 29.0– 47.7 mm SL; Amacayacu National Natural Park, unnamed forest stream, tributary of Río Pureté headwaters, 3 ° 41 ' 54 " S, 70 ° 12 ' 24 " W, c. 130 m a. s. l. IAvH-P 8300, 2, 33.5–40.8 mm SL; Amacayacu National Natural Park, unnamed forest stream tributary of Río Pureté headwaters; 3 ° 41 ' 38 " S, 70 ° 12 ' 27 " W. IAvH-P 8917, 14, 17.1–47.5 mm SL; Sufragio stream in front of Zafire Biological Station, 4 ° 0 ' 19 " S, 69 ° 53 ' 56 " W, c. 120 m a. s. l. IAvH-P 8951, 9, 17.9–50.5 mm SL, Sufragio stream in front of Zafire Biological Station; 4 ° 0 ' 20 " S, 69 ° 53 ' 56 " W, c. 120 m a. s. l. IAvH-P 9022, 6, 43.8–50.8 mm SL (including 3 c & s specimens fully disarticulated as non-types), Sufragio stream in front of Zafire Biological Station; 4 ° 0 ' 19 " S, 69 ° 53 ' 56 " W, c. 120 m a. s. l. IAvH-P 9070, 4, 48.6–55.0 mm SL, unnamed forest stream tributary of Río Calderon, 45 min. NE of Zafire Biological Station; 3 ° 58 ' 40 " S, 69 ° 53 ' 32 " W, c. 130 m a. s. l. IAvH-P 9093, 4, 23.7–47.8 mm SL; unnamed stream, tributary of Río Calderon, 45 min. NE of Zafire Biological Station; 3 ° 58 ' 40.14 " S, 69 ° 53 ' 31.8 " W, 130 m a. s. l. MPUJ 8058, 1, 49.5 mm SL, same data as for the holotype. MPUJ 8059, 1 c & s, 50.3 mm SL; unnamed forest stream tributary of Río Calderon, 45 min. NE of Zafire Biological Station; 3 ° 58 ' 40 " S, 69 ° 53 ' 32 " W, c. 130 m a. s. l. Chrysobrycon yoliae. All from PERU, Ucayali department, Coronel Portillo province, Abujao, Río Yucamia subsystem, unnamed creek, 8 ° 39 ' 14 " S, 73 ° 21 ' 17 " W, c. 273 m: MUSM 46140, holotype, 51.6 mm SL; CI-FML 5882, 3 paratypes, 44.8–52.3 mm SL (one c & s specimen, 44.8 mm SL); MLP-Ict 10517, 1 paratype, 48.4 mm SL; MUSM 46141, 8 paratypes, 38.2–51.5 mm SL.
description: Published as part of Vanegas-Ríos, James Anyelo, Urbano-Bonilla, Alexander & Sánchez-Garcés, Gian Carlo, 2024, A new species of Chrysobrycon Weitzman & Menezes, 1998 (Characiformes, Characidae, Stevardiinae) with remarkable sexually dimorphic pigmentation from the upper Río Vaupés basin, Colombian Amazon, with taxonomic key, pp. 675-689 in Zoosystematics and Evolution 100 (2) on pages 675-689, DOI: 10.3897/zse.100.121499