Hyphessobrycon cachimbensis Travassos, 1964

Marinho, Manoela Maria Ferreira & Dagosta, Fernando Cesar Paiva, 2024, Redescription of Hyphessobrycon cachimbensis (Characiformes: Characidae) with the description of a new congener from the Serra do Cachimbo, Brazil, Neotropical Ichthyology (e 230127) 22 (2), pp. 1-20 : 4-10

Hyphessobrycon cachimbensis Travassos, 1964

( Figs. 1–4 ; Tab. 1)

Hyphessobrycon cachimbensis Travassos, 1964:542 (holotype: MNRJ 9196 ; type-locality: “ Rio Cachimbo , Cachimbo , Aeroporto da FAB. Abaixo do Salto , Estado do Pará. Lat. 9º22’S e Long. 54º55’W [= rio Cachimbo at Serra do Cachimbo , airport of the Brazilian Airforce below waterfall, State of Pará, Brazil]). — Géry, 1977:478 (identification key). — Lima et al., 2003:135 (listed). — Lima, Zuanon, 2004:120 (literature compilation). — Zarske, Géry, 2004:36 (literature compilation). — Bertaco, Carvalho, 2005:442 (literature compilation). — Carvalho, Bertaco, 2006:307 (literature compilation). — Lima et al., 2007:53 (listed). — Sousa et al., 2010:262 (literature compilation). — Buckup et al., 2011:173 (photograph). — Dagosta, de Pinna, 2019:35 (shared occurrence between rio Tapajós and rio Xingu basins); 80 (wrongly assigned as endemic to rio Teles Pires). — Marinho et al., 2021:14 (information on lateral-line scale morphology). — Dagosta et al., 2022:3 (diagnosis with Hyphessobrycon comodoro ); 11 (putative relationships).

Hyphessobrycon cf. cachimbensis . — Lima, Birindelli, 2006:57 (listed under comparative material).

Hyphessobrycon cf. melanostichos . —Hoffman, Hoffmann, 2012:38 (male and female photographs).

Diagnosis. Hyphessobrycon cachimbensis can be distinguished from all congeners, except H. chiribiquete García-Alzate , Lima, Taphorn, Mojica, Urbano-Bonilla & Teixeira, 2020, Hyphessobrycon n. sp. (described below), H. comodoro Dagosta, Seren, Ferreira & Marinho, 2022 , H. cyanotaenia Zarske & Géry, 2006 , H. fernandezi Fernández-Yépez, 1972 , H. melanostichos Carvalho & Bertaco, 2006 , H. nigricinctus Zarske & Géry, 2004 , H. paucilepis García-Alzate, Román-Valencia & Taphorn, 2008 , H. petricolus Ohara , Lima & Barros, 2017, H. piranga Camelier, Dagosta & Marinho, 2018 , H. psittacus Dagosta, Marinho, Camelier & Lima, 2016, H. scholzei Ahl, 1937 , H. sovichthys Schultz, 1944 , H. stegemanni Géry, 1961 , H. taphorni García-Alzate, Román-Valencia & Ortega, 2013 , H. tuyensis García-Alzate, Román-Valencia & Taphorn, 2008 , and H. vilmae Géry, 1966 , by the presence of a well-defined, relatively narrow dark midlateral stripe on body extending from the posterior margin of the eye to the middle caudal-fin rays (vs. longitudinal stripe absent, stripe starting approximately at vertical through the dorsal-fin origin, or midlateral dark stripe becoming blurred towards the caudal peduncle). It distinguishes from the aforementioned species, except H. chiribiquete , Hyphessobrycon n. sp., H. comodoro , H. cyanotaenia , H. melanostichos , H. nigricinctus , and H. petricolus , by presenting humeral spot (vs. humeral spot absent). The new species can be diagnosed from Hyphessobrycon n. sp., H. comodoro , H. cyanotaenia , H. melanostichos , and H. nigricinctus by having 18–22 branched anal-fin rays (vs. 14–17 in Hyphessobrycon n. sp., 13–16 in H. comodoro and in H. cyanotaenia , 16–18 in H. melanostichos , and 22–26 in H. nigricintus ). Differs from H. chiribiquete by the midlateral stripe with an even width, covering more than one scale along its entire length (vs. midlateral stripe clearly decreasing in width towards the caudal peduncle) and from H. petricolus by having 14 horizontal scale rows around caudal peduncle (vs. 12) and 34–36 total scales in the longitudinal lateral series (vs. 30–32). It can be further distinguished from H. nigricinctus by having five or six longitudinal scale rows between lateral line and dorsal-fin origin (vs. seven or eight) and one to three maxillary teeth (vs. five to eight), and from H. chiribiquete , Hyphessobrycon n.

sp., H. comodoro , H. cyanotaenia , H. melanostichos , and H. petricolus by having lepidotrichia of pelvic-, dorsal-, anal- and caudal-fin rays more branched in males than in females (vs. lepidotrichia of those fins as branched in males as in females) and presence of bony spinules in pelvic and anal fins (vs. spinules absent).

Description. Morphometric data in Tab. 1. Small characid species, largest examined specimen with 56.5 mm SL. Body compressed, moderately elongate. Greatest body at dorsal-fin origin. Dorsal profile of head convex from upper lip to vertical through anterior nostril; straight to slightly concave from that point to tip of supraoccipital spine. Dorsal profile of body slightly convex along predorsal region, straight along dorsal-fin base, straight to slightly convex from terminus of dorsal-fin base to adipose-fin origin, and concave along caudal peduncle. Ventral profile of head and body slightly convex from tip of lower jaw to pectoral-fin origin, convex from that point to pelvic-fin origin, straight from that point to anal-fin origin, markedly convex along anal-fin base in males and straight to slightly convex in females (see Sexual dimorphism), and concave along caudal peduncle.

Anterior tip of upper and lower jaws aligned, mouth terminal. Premaxillary teeth in two rows ( Fig. 3 ). Outer row with 2(7), 3*(22), or 4(2) teeth bearing five cusps. Inner row with 5*(31) or 6 (1) teeth with seven to nine cusps except symphyseal teeth, bearing six cusps. Posterior tip of maxilla extending to vertical through posterior half of second infraorbital. Maxilla with 1(2), 2*(27), or 3(3), with three to seven cusps. Dentary with 5*(30) larger teeth with seven to nine cusps, decreasing in size laterally, followed by one smaller tricuspid tooth in most specimens, and by one to three diminutives, conical to tricuspid teeth. Central median cusp more developed than lateral cusps in all cuspidate teeth. Four branchiostegal rays (6). First gill arch with 2(6) gill rakers on hypobranchial, 8(4) or 9(2) rakers on ceratobranchial, 1(6) rakers on intermediate cartilage, and 5(5) or 6(1) rakers on epibranchial.

Scales cycloid, with 3 to 7 radii, from focus to posterior border of scales; circuli weakly developed proximally and absent distally. Total scales in the longitudinal lateral series 34*(6), 35(10), or 36(7). Scales on the lateral series variably perforated. Twenty specimens with 8(1), 9(1), 11(2), 10(2)12*(3), 13(2), 14(3), 15(3), 16(4), 17(2), 20(1), or 23(1) pored scales, followed by non-pored ones (incomplete lateral line) and three specimens with pored scales interspersed with non-pored ones (discontinuous lateral line), as follows: 17 pored + 2 non-pored + 2 pored + 14 non-pored; 12 pored + 1 non-pored + 2 pored + 20 non-pored; and 10 pored + 2 non-pored + 2 pored + 21non-pored. Longitudinal scale rows between dorsal-fin origin and lateral line 5*(14) or 6(15). Longitudinal scale rows between lateral line and pelvic-fin origin 4*(26) or 5(3). Predorsal scales 9(2), 10(11), 11*(13), or 12(5), in single series. Horizontal scale rows around caudal peduncle 14*(23). Base of anteriormost anal-fin rays covered by series of 3 to 5 scales. Caudal fin not scaled.

Supraneurals 5(5) or 6(1), with dorsal bony lamellae. Dorsal-fin rays ii,9*(32). Proximal tip of first dorsal-fin pterygiophore inserted posterior to neural spine of 9 th (3) or 10 th (3) vertebra. Pectoral-fin rays i*(23), 10(11), 11*(15), or 12(6). Pelvic-fin rays i*(23), 6(1) or 7*(30) or 8(1). Adipose-fin origin at vertical through base of 11 th to 13 th branched anal-fin rays. Anal fin with iv(4) or v(2), 18(3), 19(8), 20*(8), 21(11), or 22(3) rays. See Sexual Dimorphism section for description of anal-fin profile. Proximal tip of first anal-fin pterygiophore inserted posterior to haemal arch of 16 th (3) or 17 th (1) or haemal spine of 16 th (1) or 18 th (1) vertebra. Dorsal procurrent caudal-fin rays 7(1), 9(1), 10(2), 11(1), or 12(1). Ventral procurrent caudal-fin rays 9(2), 10(3), or 11(1). Caudal-fin with i,8,9,i (32) rays. Caudal fin forked with similar sized lobes. Total vertebrae 33(3), 34(2), or 36(1): precaudal vertebrae 15(1), 16(4), or 17(1) and caudal vertebrae 17(2), 18(3), or 19(1).

Coloration in alcohol. Overall ground coloration of head and body pale yellow to ocher ( Figs. 1 , 2 ). Dorsal portion of head and body darker. Snout, jaws and maxilla with concentration of dark chromatophores, infraorbital series with scattered dark pigmentation, except for the 5 th and 6 th infraorbitals, which are densely pigmented with dark chromatophores, continuing with the dark longitudinal stripe. Upper half of opercle densely pigmented with dark chromatophores, lower half only with sparse dark pigmentation. Middorsal portion of body with slight reticulated pattern. Humeral blotch large and conspicuous, with diffuse borders, encompassing approximately three scales horizontally and four vertically. Dark midlateral stripe on body two to three scales wide, extending from posterior margin of the eye to tip of middle caudal-fin rays. Abdominal region with only sparse chromatophores, mainly at margin of the scales; scattered dark chromatophores above anal fin. Dorsal, pectoral, pelvic, anal and caudal fins with dark chromatophores scattered along edge of lepidotrichia and concentration of dark chromatophores in interradial membranes, mainly at distal half. Anal fin frequently with distal margin intensely pigmented. Adipose fin with concentration of brown chromatophores. Caudal-peduncle blotch absent. Pigmentation at middle caudal-fin rays frequently darker than the chromatophores of midlateral stripe, especially on juveniles.

Coloration in life. Dark chromatophores pattern described in Color in alcohol section, except by the concentration of dark pigmentation in the posterior third of the eye, just after the pupil. Overall coloration of body yellow to olive. Red pigmentation around pupil. Caudal peduncle and base of caudal-fin rays yellow. Dorsal, pectoral, pelvic, anal fins and distal portions of caudal-fin lobe red to orange. Distal tip of first three to four dorsal-fin rays white. Adipose fin yellow to orange ( Fig. 4 ).

Sexual dimorphism. Hyphessobrycon cachimbensis presents a series of sexual dimorphic traits, mostly related to fin morphology ( Figs. 2 , 4 ), namely: (1) distal portion of all branched anal-fin rays and in the four lateralmost pelvic-fin rays of males with bony spinules, amount and distribution of spinules along rays varies intraspecifically; (2) dorsal-fin profile of males slightly rounded whereas in females it is falcate; (3) when adpressed, pectoral and pelvic fins reaches the pelvic and anal fins, respectively, in males not in females; (4) pelvic fin of males with most rays of similar size whereas in females, the lateralmost rays are longer, remaining rays decreasing in size medially; (5) anal-fin base convex in males and straight in females, due to thicker musculature in the area; (6) anal-fin distal profile straight to convex in males, not forming an anterior lobe vs. slightly falcate in females, forming an anterior lobe; and (7) males larger than females.

Geographical distribution. Known from the Serra do Cachimbo , in the headwaters of the rio Curuá , tributary of the rio Iriri , rio Xingu basin and the headwaters of the Igarapé Santa Úrsula and rio Braço Norte , both tributaries of the rio Teles Pires , rio Tapajós basin, Pará State, Brazil ( Fig. 5 ). Coordinates of MZUSP 30358 and 31819 do not correspond to given localities (i. e., rio Curuá , rio Xingu basin, and rio Teles Pires, rio Tapajós basin, respectively), therefore these holdings were not mapped in Fig. 5 .

Conservation status. Hyphessobrycon cachimbensis is endemic from the Serra do Cachimbo, in the headwaters of the rio Curuá, tributary of the rio Iriri, rio Xingu basin and the headwaters of the igarapé Santa Úrsula and rio Braço Norte, both tributaries of the rio Teles Pires, rio Tapajós basin. Despite forest degradation in some of the areas where the species occurs, the surrounding regions are well-preserved, with a significant portion of the drainage systems located within protected areas such as the Reserva Biológica Nascentes da Serra do Cachimbo and the FAB Military Zone. It is noteworthy that the region is poorly sampled, field expeditions being concentrated in the vicinity of road BR-163. Therefore, H. cachimbensis should be classified as Least Concern (LC) following the International Union for Conservation of Nature (IUCN) categories and criteria (IUCN Standards and Petitions Subcommittee, 2022).

Remarks. The records of Hyphessobrycon cachimbensis by Zarske, Géry (2006: fig.

17) from the rio Tocantins drainage and Hyphessobrycon cf. cachimbensis by Géry, Junk

(1977) and Lima et al. (2014) from the rio Aripuanã in fact refer respectively to H.

stegemanni and H. vilmae .

Material examined. Hyphessobrycon cachimbensis : All from Brazil. Rio Amazonas basin. Rio Tapajós basin: MNRJ 9196 , holotype , 30.6 mm SL. MNRJ 34466 , 157 ,

18.4–40.9 mm SL, 7 mol. MNRJ 34467, 398, 17.2–41.2 mm SL, 5 mol. MPEG 7774, 18,

16.9–31.6 mm SL. MPEG 7801, 53, 15.5–40.9 mm SL. MZUSP 116642, 5, 27.3–30.8

mm SL (2, 28.5–31.3 mm SL). MZUSP 119918, 90, 25.3–42.7 mm SL. Rio Xingu basin: MZUSP 30358, 68, 21.1–31.6 mm SL, 2 c&s. MZUSP 31819, 2, 28.9–31.55

mm SL. MZUSP 96879, 8, 37.6–44.8 mm SL. MZUSP 97586, 64, 19.9–45.0 mm SL.

MZUSP 97599, 16, 25.0– 45.4 mm SL. MZUSP 101377, 17, 33.1–56.5 mm SL (13,

48.4–56.5 mm SL), 1 c&s, 54.4 mm SL. MZUSP 101386, 4, 14.7–28.1 mm SL. MZUSP

101416, 31, 19.4–46.9 mm SL (5, 37.4–46.9 mm SL), 5 c&s, 34.6–43.9 mm SL. MZUSP

124623, 10, 41.0– 52.2 mm SL. MZUSP 124633, 33, 30.3–56.4 mm SL. MZUSP 128238,

139, not measured.

Figures

FIGURE 1 | Holotype of Hyphessobrycon cachimbensis, MNRJ 9196, 30.6 mm SL, rio Cachimbo, Cachimbo, airport of Brazilian airforce, below waterfall, State of Pará, Brazil. Credits: South American Characiformes Inventory project (SACI).

FIGURE 2 | Hyphessobrycon cachimbensis, MZUSP 101377, Brazil, Pará, rio Xingu basin, rio Iriri drainage, tributary of rio Curuá at bridge of BR-163 road. A. 51.6 mm SL, male; B. 48.3 mm SL, female.

FIGURE 3 | Lateral view of upper and lower jaws of Hyphessobrycon cachimbensis, MZUSP 101416. Scale bar = 0.5 mm.

FIGURE 4 | Living specimens of Hyphessobrycon cachimbensis, not catalogued, Brazil, rio Teles Pires, Novo Progresso, tributary of the rio Braço Norte at the Favaretto farm. A. Male; B. Female.

FIGURE 5 | Distribution map of Hyphessobrycon cachimbensis (pink); Hyphessobrycon n. sp. (yellow). Stars represent type-localities. The typelocality of Hyphessobrycon cachimbensis is the same as the FAB Airport - Campo de Provas Brigadeiro Velloso. Dashed line delineates the watershed boundary between the rio Tapajós and rio Xingu basins.