Hyphessobrycon weitzmanorum, Lima & Moreira, 2003

Lima, Flávio C. T. & Moreira, Cristiano R., 2003, Three new species of Hyphessobrycon (Characiformes: Characidae) from the upper rio Araguaia basin in Brazil, Neotropical Ichthyology 1 (1), pp. 21-33 : 27-30

Hyphessobrycon weitzmanorum , new species Figs. 9-10

Holotype. MZUSP 73315 (male, 22.1 mm SL): Brazil, Mato Grosso, município de Alto Araguaia, córrego Mosquito, km 476.3 of Ferronorte railroad, 17°25’8”S, 53°13’60”W; C. R. Moreira & F.C. T. Lima, 19 May 2001.

Paratypes. All localities in Brazil, Mato Grosso, município de Alto Araguaia : MZUSP 73314 (93, 5 cs, 13.9-25.5 mm SL) ; MCZ 162372 (5, 18.2-22.6 mm SL) ; USNM 371924 (5, 19.7-20.7 mm SL), same data as holotype . MZUSP 73317 (26, 12.6-20.0 mm SL), córrego do Sapinho, km 474.64 of Ferronorte railroad, 17°25’55”S, 53°14’34”W; C . R. Moreira & F.C. T. Lima, 19 May 2001 . MZUSP 73342 (25, 12.6-21.4 mm SL), ribeirão de Sapo, km 464.04 of Ferronorte railroad, 17°31’11”S, 53°15’33”W; C . R. Moreira & F.C. T. Lima, 21 May 2001 . MZUSP 73271 (20, 12.9- 22.1 mm SL), córrego Boiadeiro, km 487.08 of Ferronorte railroad, 17°20’1”S, 53°14’53”W; C . R. Moreira & F.C. T. Lima, 16 May 2001 . MZUSP 73254 (49, 10.3-22.3 mm SL) ; MNRJ 24782 (5, 18.3-19.7 mm SL), córrego Gordura, km 491.4 of Ferronorte railroad, 17°18’20”S, 53°16’22”W; C . R. Moreira & F.C. T. Lima, 15 May 2001 .

Diagnosis. Hyphessobrycon weitzmanorum is distinguished from all congeners, except H. tortuguerae Böhlke , H. bifasciatus Ellis , H. savagei Bussing , H. flammeus Myers , H. griemi Hoedeman , H. balbus Myers , H. itaparicensis Lima & Costa, and H. columbianus Zarske & Géry , by possessing two humeral spots. Hyphessobrycon weitzmanorum is distinguished from H. bifasciatus , H. savagei , H. flammeus , H. tortuguerae , H. griemi , H. itaparicensis , and H. columbianus by possessing a general dark color pattern, due to a high concentration of dark chromatophores uniformly distributed over the lateral surfaces of the body (vs. a general clear color pattern, with few, scattered chromatophores over the lateral surfaces of the body). Additionally, Hyphessobrycon weitzmanorum differs from H. bifasciatus , H. griemi , and H. tortuguerae by possessing two intensely pigmented, vertically-elongate humeral spots (vs. second humeral blotch fainter in H. bifasciatus ; first humeral blotch fainter in H. griemi ; and both humeral blotches small, not vertically-elongate in H. tortuguerae ). Hyphessobrycon weitzmanorum is distinguished from H. flammeus and H.

savagei by possessing wide humeral blotches, with somewhat rounded margins (vs. humeral blotches narrow, with straight margins). Hyphessobrycon weitzmanorum is distinguished from H. balbus in possessing 5-9 perforated lateral line scales (vs. 11-22) and in having the second humeral blotch intensely pigmented (vs. very faint). Hyphessobrycon weitzmanorum is distinguished from H. itaparicensis Lima & Costa (2001) by possessing a lower number of branched anal-fin rays (17-21, vs. 22-25) and lack of a midlateral, horizontal stripe, crimson in life, that extends from the vertical just posterior of the dorsalfin origin to the caudal peduncle. Hyphessobrycon weitzmanorum is distinguished from H. columbianus Zarske & Géry (2002) , by possessing a lower number of branched anal-fin rays (17-21, vs. 23-24) and orange pigmentation in life on the caudal, anal, dorsal and pelvic fins (vs. red pigmentation on caudal, and anal).

Description. Morphometric data of the holotype and paratypes are presented in Table 3 . Body compressed,

moderately deep, greatest body depth at vertical through middle of distance between pectoral- and pelvic-fin insertions. Dorsal profile of head convex from upper lip to vertical through middle of orbit; slightly concave from latter point to tip of supraoccipital spine. Predorsal profile of body convex, dorsalfin base straight to slightly convex, posteroventrally inclined. Body profile straight to convex from end of dorsal-fin base to adipose fin; slightly concave to slightly convex between latter point to origin of dorsalmost procurrent caudal-fin ray. Ventral profile of head and body convex from lower lip to anal-fin origin. Body profile along anal-fin base straight to slightly convex and posterodorsally inclined. Ventral profile of caudal peduncle slightly concave to slightly convex.

Jaws equal, mouth terminal. Maxilla reaching posteriorly to first third of the orbit. Premaxillary teeth in two rows ( Fig. 11 ). Outer row with 2(4) unicuspid teeth. Inner row with 5(1) or 6(3) uni- to tricuspid teeth. Maxilla with 3(1), 4(2), 5(1), or 6(1), unito tricuspid teeth. Dentary with 4(4) or 5(1) large tri- to tetracuspid teeth followed by 7 to 11 smaller unicuspid teeth.

Scales cycloid, with few radii. Lateral line incompletely pored, with 5(5), 6(12), 7(15), 8(4), or 9(2) perforated scales. Lateral series scales including perforated scales 31(12), 32(10), 33*(11), 34(4), or 35(1). Horizontal scale rows between dorsal-fin origin and lateral line 6(17) or 7(23), not including scale of predorsal series situated just anterior to first dorsal-fin ray. Horizontal scale rows between lateral line and pelvic-fin origin 4(2), 5(34), and 6(3). Predorsal scales 9*(10), 10(20), 11(2), or 13(1). Circumpeduncular scales 12(1), 13(17), 14*(9), or 15(1). Single row of 4-6 scales cover base of anteriormost anal-fin rays.

Dorsal-fin rays iii,8*(32), iv,8(1), ii,9(16), iii,9(2), or ii,10(1). Dorsal-fin origin slightly anterior to middle of the standard length. First dorsal-fin pterygiophore inserting behind neural spine of 8th(4), or 9th(1) vertebra. Adipose fin present. Unbranched anal-fin rays iii*(45), or iv(12). Branched anal-fin rays 17(9), 18*(25), 19(17), 20(5), or 21(1). Anal-fin origin approximately at vertical through antepenultimate dorsal-fin rays. First anal-fin pterygiophore inserting behind hemal spine of 14th(3), or 15th(2) vertebra. Pectoral-fin rays i,8(3), 9(28), 10*(27), or 11(1). Tip of pectoral fin reaching vertical through, or slightly beyond, pelvic-fin insertion. Pelvic-fin rays i,6*(59). Tip of pelvic fin usually reaching vertical through, or slightly beyond, anal-fin origin, but falling short of anal-fin origin in some specimens. Caudal fin forked, upper and lower lobes rounded, and similar in size. Principal caudal-fin rays 10+9(5). Ten(4), or 11(1) dorsal procurrent caudal-fin rays, and 8(1), 9(2) or 10(1) ventral procurrent caudal-fin rays. First gill arch with 7(5) epibranchial, 8(1), 9(3), or 10(1) ceratobranchial, 1(5) on cartilage between ceratobranchial and epibranchial, and 2(5) hypobranchial gill-rakers. Four(5) branchiostegal rays, 3(5) on anterior ceratohyal, and 1(5) on posterior ceratohyal. Vertebrae 32(4), or 33(1). Supraneurals 4(3), or 5(1).

Sexual dimorphism. One cleared and stained mature male (MZUSP 73314), with small hooks on unbranched, and 4 anteriormost branched pelvic-fin rays. One hook per segment usually present on distal two-thirds of rays. Anal fin with small hooks on last unbranched, and six anterior most branched rays. Usually, two paired hooks per segment on distal one-half of rays. In whole specimens, the heavy concentration of dark chromatophores makes examination of the hooks difficult.

Color in alcohol. Ground color cream. Guanine present on opercle and infraorbitals. Dark chromatophores densely concentrated on dorsal surface of head and anterior surface of lower jaw. Small dark chromatophores present on maxilla, ventral margin of orbit, and first and second infraorbitals; remaining infraorbitals and opercle with larger and more scattered dark chromatophores. Ventral portion of head with very small, scattered, dark chromatophores. Dorsal midline of body with dense concentration of dark chromatophores. Lateral surfaces of body densely covered with dark chromatophores, less concentrated on anterior portion of abdominal cavity. Two vertically-elongate black humeral spots. Anterior humeral spot well-defined, roughly rectangular, with dark chromatophores more concentrated on its approximately dorsal one-half. Second humeral spot less defined, variously shaped, with border ranging from roughly rectangular to more or less circular. Faint dark, relatively wide, midlateral stripe, extending from second humeral spot to rear of caudal peduncle. Some specimens with faint dark stripe running along anal-fin base. Densely concentrated dark chromatophores present on fins, most prominently on dorsal and anal fins. Caudal fin with middle rays more darkly pigmented than remainder of fin.

Color in life. Based on four photographed exs (MZUSP 73314, 2 exs, 21.5-23.4 mm SL; MZUSP 73254, 1 ex, 20.7 mm SL; MZUSP 73271, 1 ex, 22.7 mm SL; Fig. 10 ). Dorsolateral portion of body and caudal peduncle gray to dark gray. Sides of head silvery. Ventrolateral portion of body, except on caudal peduncle, grayish pale, with bluish, bright silvery coloration. Deep gray stripe present on anal-fin base. Dorsal and ventral midlines bright orange. Orange pigmentation present on basal portion of dorsal and caudal fin, distal portion of anal-fin lobe, and pelvic fin. Black stripe extends along middle caudalfin rays.

Geographic distribution. Hyphessobrycon weitzmanorum is known from tributaries of the upper rio Araguaia basin in the state of Mato Grosso, Brazil ( Fig. 5 ).

Ecological notes. Hyphessobrycon weitzmanorum was usually collected in relatively large, clearwater streams with abundant aquatic vegetation. The single exception was the type locality, córrego Mosquito, which was a first-order, relatively small stream running through a large wetland covered by tall grass. In all streams, H. weitzmanorum was observed in small groups of 2-5 individuals, that were sometimes apparently associated with Cnesterodon septentrionalis (Poeciliidae) . Hyphessobrycon weitzmanorum was always associated with submerged vegetation. Córrego Gordura, where more detailed subaquatic observations of H. weitzmanorum were conducted, was a wide stream (6-10 m), with deep, sandybottomed pools (2-4 m) alternating with shallow, vegetationcovered riffles (0.30-1 m). In this stream, H. weitzmanorum was often seen at sites along steep banks just below the riffles, with abundant vegetation and slow-flowing water. Individuals positioned in those locations undertook brief incursions into the fast-flowing water in higher portions of the water column, in order to pick drifting items in the current. Some North American cyprinids have also been reported to hover outside strong currents, darting into it to pick up drifting items ( Matthews, 1998: 314, 414). For remarks on the syntopy of H. weitzmanorum with H. langeanii and H. eilyos , see “Ecological notes” above under H. langeanii .

Etymology. The specific name honors Stanley and Marilyn Weitzman, for their life-long interest and extensive contributions to the knowledge of Neotropical freshwater fishes. Including are several papers addressing the systematics of Hyphessobrycon and related genera.

Figures

Fig. 9. Hyphessobrycon weitzmanorum, holotype, MZUSP 73315, 22.1 mm SL, Brazil, Mato Grosso, município de Alto Araguaia, córrego Mosquito.

Fig. 10. Paratype of Hyphessobrycon weitzmanorum, MZUSP 73314, 21.5 mm SL, Brazil, Mato Grosso, município de Alto Araguaia, córrego Mosquito. Photographed in life.

Fig. 11. Paratype of Hyphessobrycon weitzmanorum, MZUSP 73314. Upper and lower jaws, lateral view, left side. Scale bar 1mm.

Fig. 5. Upper rio Araguaia basin, showing sites of occurrence of Hyphessobrycon langeanii, H. eilyos, and H. weitzmanorum (diamonds), H. langeanii and H. weitzmanorum (dots), H. langeanii and H. eilyos (triangle), or H. langeanii (squares). 1. Ribeirão do Sapo, type locality of H.eilyos. 2. Córrego Mosquito, type locality of H. langeanii and H. weitzmanorum.

Tables

Table 3. Morphometric data for Hyphessobrycon weitzmanorum. Measurements based on the holotype (MZUSP 73315) and 53 paratypes (MZUSP 73254, 9 ex.; MZUSP 73271, 5 ex.;MZUSP 73314,29 ex.;MZUSP 73317,5 ex.; MZUSP 73342, 5 ex.).

	holotype n		range	mean
Standard length (mm)	22.1	54	17.2-25.5	-
Percents of standard length
Depth at dorsal-fin origin	45.5	54	36.5-46.5	41.3
Snout to dorsal fin origin	49.2	54	47.3-53.3	50.3
Snout to pectoral-fin origin	28.4	54	25.6-29.3	27.5
Snout to pelvic-fin origin	50.0	54	44.5-51.0	48.0
Snout to anal-fin origin	64.8	54	58.6-67.0	62.7
Caudal peduncle depth	14.7	54	10.3-15.0	12.9
Caudal peduncle length	15.1	54	10.7-16.2	13.3
Pectoral-fin length	24.9	54	20.4-26.5	23.8
Pelvic-fin length	19.0	54	15.5-21.6	18.5
Dorsal-fin base length	18.5	54	14.5-19.1	17.3
Dorsal-fin height	37.5	54	30.2-43.2	36.7
Anal-fin base length	29.9	54	27.3-34.1	30.6
Anal-fin lobe length	23.9	54	17.9-25.3	21.4
Eye to dorsal-fin origin	36.8	54	33.7-39.5	36.8
Dorsal-fin origin to caudal-fin	59.3	54	50.6-60.9	56.4
base
Bony head length	27.1	54	25.3-29.2	27.2
Percents of head length
Horizontal eye diameter	40.2	54	35.2-51.1	41.5
Snout length	21.9	54	15.9-24.7	20.6
Least interorbital width	34.4	54	26.9-37.2	32.0
Upper jaw length	46.4	54	39.0-54.4	44.6