Hyphessobrycon peugeoti, Ingenito & Lima & Buckup, 2013

Ingenito, Leonardo F. S., Lima, Flávio C. T. & Buckup, Paulo A., 2013, A new species of Hyphessobrycon Durbin (Characiformes: Characidae) from the rio Juruena basin, Central Brazil, with notes on H. loweae Costa & Géry, Neotropical Ichthyology 11 (1), pp. 33-44 : 34-37

Hyphessobrycon peugeoti , new species Figs. 1-4

Holotype. MNRJ 38988 , 30.5 mm SL, male, Brazil, Mato Grosso State, Cotriguaçu, stream at fazenda São Nicolau, left margin tributary of rio Juruena , 09°52’02.3”S 58°16’45.6”W, 5 May 2006, P. A. Buckup, L. F. S. Ingenito, I. L. Assumpção & G. A. Araújo.

Paratypes. Brazil. Mato Grosso State: MNRJ 29503 , 1 , male, 28.6 mm SL, Cotriguaçu, stream at fazenda São Nicolau, left margin tributary of rio Juruena , 09°51’33.4”S 58°15’19.8”W, 5 May 2006, P. A. Buckup, L. F. S. Ingenito, I. L. Assumpção & G. A. Araújo . MNRJ 29609 , 11 , 9 males (1 c&s, 27.3 mm SL) and 2 females, 22.6-28.9 mm SL, Cotriguaçu, small stream at fazenda São Nicolau, left margin tributary of rio Juruena , 09°51’42.8”S 58°14’55.3”W, 6 May 2006, P. A. Buckup, L. F. S. Ingenito, I. L. Assumpção & F. B. Freitas . MNRJ 29521 , 2 , males, 29.7 and 30.8 mm SL, collected with the holotype . MZUSP 77734 , 67 , 6 males, 61 unsexed juveniles, 12.6-31.7 mm SL (6 c&s, 15.6-21.1 mm SL) ; ANSP 190999 , 2 , 1 male, 1 female, 22.5 and 31.7 mm SL ; ZUEC 6362 , 2 , 1 male, 1 female, 20.5 and 30.2 mm SL, Juruena, rio Juruena, ca. 1 km below mouth of rio Arinos , 10°23’42”S, 58°19’58”W, 25-26 Jul 1997, F. A. Machado, C. M. C. Leite, M. F. Catarino & C. H. Melo .

Diagnosis. Hyphessobrycon peugeoti n. sp. can be distinguished from all congeners, with the exception of H. elachys Weitzman , H. heliacus Moreira, Landim & Costa , and H. loweae , by a conspicuously elongated and filamentous dorsal fin in mature males (vs. dorsal and pelvic fins, when elongated, never filamentous). Hyphessobrycon peugeoti can be distinguished from these species by its overall red color in life (vs. a general clear/silvery color in H. elachys , and golden color in H. heliacus and H. loweae ). Additionally, H. peugeoti can be distinguished from H. elachys by possessing an anal fin with a straight margin in mature males (vs. a distinctly rounded anal-fin lobe present in H. elachys mature males); from H. heliacus it differs by possessing shorter pelvic-fins in fully mature males, reaching only the second anal-fin branched ray (vs. pelvic-fins filamentous, reaching up to the sixth anal-fin branched ray in H. heliacus ), and by lacking chevron-like dark markings along the midline (vs. chevron-like dark markings along the midline present in H. heliacus ); from H. loweae it differs by possessing a lower number of horizontal scale rows between the dorsal-fin origin and the lateral line (5 vs. 6-7 in H. loweae ), and by possessing a higher number of branched anal-fin rays (21-24, modally 22, vs. 17-21, modally 20 in H. loweae ).

Description. Morphometric data in Table 1 . Body compressed, moderately deep, greatest body depth slightly anterior to dorsal-fin origin. Dorsal profile of head convex from upper lip to vertical through posterior nostril; straight to slightly convex from nostril to tip of supraoccipital spine. Predorsal profile of body slightly convex, dorsal-fin base straight to slightly convex, posteroventrally inclined. Body profile straight to slightly concave from dorsal-fin base to adipose fin; concave between latter point and origin of anteriormost procurrent caudal-fin ray. Ventral profile of head and body slightly convex to pelvic-fin origin; slightly concave from that point to anal-fin origin; straight to slightly convex, posteriorly slanted along anal-fin base; slightly concave along caudal peduncle.

Mouth terminal, anteroventral end of dentary protruding slightly. Maxilla slightly surpassing vertical line through anterior margin of orbit. Premaxillary teeth in two rows. Outer row with three (12*) or four (2) tetra- to hexacuspid teeth. Inner row with five (12*) or six (2) hexato heptacuspid teeth. Maxilla with two (10*) or three (4) tetra- to pentacuspid teeth. Dentary with five large pentato heptacuspid teeth followed by three to six smaller unito tricuspid teeth ( Fig. 3 ).

gill arch with seven epibranchial, nine ceratobranchial, three hypobranchial gill-rakers (1). Four branchiostegal rays (1). Vertebrae 32(4), or 33(3). Supraneurals four (4), or five (2).

Scales cycloid, with four to seven radii; circuli strongly marked anteriorly, but absent distally (“ Hemigrammus type ” of Cockerell, 1915). Lateral line incompletely pored, with four (1), five (4), six (3), seven (8*), or eight (4) perforated scales. Lateral-series scales including perforated scales 26(1), 29(1), 30(1), 31(2), 32(5*), 33(1), or 34(3). Horizontal scale rows between dorsal-fin origin and lateral line five (22*), not including half scale of predorsal series situated just anterior to first dorsal-fin ray. Horizontal scale rows between lateral line and pelvic-fin origin four (21*). Scales around caudal peduncle 11(3) or 12(10*). Single row of three to five scales covering base of anteriormost anal-fin rays.

Dorsal-fin rays ii,9, not including small ossification anterior to first unbranched ray, discernible only in c&s specimens, present in five out of seven c&s specimens. Dorsal-fin origin at mid-body. Base of last dorsal-fin ray at vertical through anal-fin origin. First dorsal-fin pterygiophore inserting behind neural spine of ninth (7) vertebra. Dorsal-fin very elongated in mature males specimens, reaching area between adiposefin origin and first fourth of caudal fin when depressed; first to third branched dorsal-fin rays longest.Adipose fin present. Anal-fin rays iv (19*) or v (1), 21(5), 22(11*), 23(6), or 24(1). First anal-fin pterygiophore inserted behind hemal spine of sixteenth (6), or seventeenth (1) vertebra. Anal-fin margin slightly convex in males, with almost all rays thick, curved posteriorly; first to fifth branched rays slightly longer than remaining rays, decreasing in length gradually, not forming lobe.Anal-fin margin anteriorly pointed in females, with fourth to twelfth rays more elongate, forming discrete lobe, remaining rays gradually decreasing in length posteriorly. Pectoral-fin rays i,9(2), 10(15), 11(6), or 12(1); tip of fin generally surpassing pelvic-fin origin. Pelvic-fin rays i,7; tip of fin reaching insertion of first to fourth anal-fin rays. Caudal-fin rays i,16(1) or 17(3*),i. Caudal fin forked; upper and lower lobes similar in size. First Color in alcohol. Ground color pale to light yellowish. Guanine pigmentation present on opercular and infraorbital series, and on few scales in some specimens. Body covered by scattered dark chromatophores, except at ventral regions of head and abdomen, which are clear. Dorsal surface of head and body, from snout to caudal fin, presenting dense concentration of dark chromatophores. Humeral region with vertically elongated, roughly rectangular dark blotch, tapering ventrally, at level of second and fourth lateral line scales. Blotch one and half scales wide, three to three and half scales high. Narrow midlateral stripe formed by chromatophores at myosepta between hypaxial and epaxial bundles of muscles, more conspicuous posteriorly to dorsal-fin base. Dark chromatophores distributed along myomeres junctions forming chevron marks, except at region immediately above anal-fin base, where dark chromatophores are uniformly scattered. Caudal peduncle blotch black, widely expanded in larger specimens, forming broad rectangular blotch occupying entire caudal peduncle surface. Dorsal, adipose, and caudal fins with considerable amount of dark chromatophores, imparting overall dark coloration to these fins. Dark chromatophores of dorsal fin more concentrated over its apical portion. Pectoral and pelvic fins hyaline, with few, scattered dark chromatophores. Anal fin hyaline, with some scattered dark chromatophores on interradial membranes.

Color in life. Based on photograph of freshly collected holotype ( Fig. 4 ). Top of head and dorsal portion of body dark red. Lateral and ventral portions of body silvery, suffused with red

L. F. S. Ingenito, F. C. T. Lima & P. A. Buckup 37

chromatophores which impart overall carmine red coloration. Dorsal, pectoral, pelvic, and anal fins carmine red. Caudal peduncle blotch dark. Caudal fin hyaline, with some diffuse dark and reddish pigmentation. Female coloration in life not recorded.

Sexual dimorphism. Adult males of Hyphessobrycon peugeoti are readily discernible from females by presenting an elongation of the dorsal fin that becomes filamentous, reaching, when depressed, the caudal-fin basis in fully grown specimens, and an approximately straight margin, and thickened rays in the anal fin. This fin morphology contrasts with the normally developed dorsal fin and the lobed anal fin of females (compare Figs. 1 and 2 ). The caudal peduncle blotch is also more developed in adult males. These dimorphic features are also found in H. heliacus and H. loweae . Fin hooks, a common feature of mature characid males ( Malabarba & Weitzman, 2003) are absent (see Discussion, below).

Habitat and ecological notes. Specimens of Hyphessobrycon peugeoti was collected in shallow areas (less than 1 m deep) in the early dry season. The type locality of H. peugeoti was a swampy deforested area, alongside a detour of road MT-208 (old road BR-80) immediately downstream from a preserved tract of native forest; the water flow was choked with grasses and small shrubs. Sample MNRJ 29609 was collected downstream where the stream crossed the dry and muddy bottom of a dam that was burst open by heavy rains about two months earlier. The single specimen MNRJ 29503 was collected in a flowing stream with sandy bottom, transparent water, and poorly-developed aquatic vegetation. Paratypes ANSP 190999, MZUSP 77734, and ZUEC 6362 were collected in a flooded area adjacent to the rio Juruena.

Distribution. Hyphessobrycon peugeoti is only known from tributaries of the middle rio Juruena, upper rio Tapajós basin, Mato Grosso State, Brazil ( Fig. 5 ).

Etymology. Hyphessobrycon peugeoti is patronymic to the Peugeot family, who invented the Peugeot pepper mill mechanism in 1842 and whose manufacturing business led to the establishment of a carbon sink reforestation project in the fazenda São Nicolau, in central Brazil, and eventually to the discovery of this new species.

Figures

Fig. 1. Hyphessobrycon peugeoti new species, holotype, MNRJ 38988, 38.5 mm SL, male, Brazil, Mato Grosso State, Cotriguaçu, tributary of rio Juruena.

Fig. 2. Hyphessobrycon peugeoti new species, paratype, MZUSP 77734, 25.9 mm SL, female, Brazil, Mato Grosso State, rio Juruena.

Fig. 3. Hyphessobrycon peugeoti new species, paratype, MNRJ 29609, 27.3 mm SL: left premaxillary, dentary, and maxillary bones in mesial view. Scale bar: 100 µm.

Fig. 4. Hyphessobrycon peugeoti, new species, holotype, MNRJ 38988, 38.5 mm SL, male, Brazil, Mato GrossoState, Cotriguaçu, tributary of rio Juruena, immediately before fixation.

Fig. 5. Map ofcentral SouthAmerica,showing known localities of Hyphessobrycon peugeoti n. sp. (yellow squares) and H. loweae (red dots). The northern square includes the typelocality and two other localities of Hyphessobrycon peugeoti. Inset depicts the area of South America displayed in the map.