Tetragonopterus huambonicus Steindachner, 1882: 177 Hemibrycon huambonicus H . polyodon (Günther)) A review of the Cis-Andean species of Hemibrycon Günther (Teleostei: Characiformes: Characidae: Stevardiinae), with description of two new species Bertaco, Vinicius A. Malabarba, Luiz R. Neotropical Ichthyology 2010 2010-12-31 8 4 737 770 3KLZG (Steindachner, 1882) Steindachner 1882 [874,1400,1799,1823] Actinopterygii Characidae Hemibrycon Animalia Characiformes 6 743 Chordata species huambonicus   Figs. 8-9      Tetragonopterus huambonicus Steindachner, 1882: 177(original description, typelocality: Huambo [ Peru]).   Hemibrycon huambonicus. - Eigenmann, 1910: 432(synonym of  H. polyodon(Günther)). - Eigenmann, 1927: 402(in key), 410-411 (redescription, and valid species).   Diagnosis.  Hemibrycon huambonicusis distinguished from most of its congeners by the number of lateral line scales (44- 48 vs. 39-43 or 48-58, Fig. 3). From the species sharing similar lateral line counts, it differs from  H. beni, and  H. dentatusby the number of branched anal-fin rays (22-27 vs. 15-19 and 28- 34, respectively); from  H. cairoenseby the number of scale rows above lateral line (8-10 vs. 6-7); from  H. helleriby the number of scales along anal-fin base scale sheath (17-26 vs. 6- 12) and the number of scale rows above lateral line (8-10 vs. 7- 8), from  H. polyodonby the number of caudal peduncle scales (18-20 vs. 16), head length (22.0-26.0 vs. 20.9-22.9% SL), and upper jaw length (45.2-52.6 vs. 43.7-45.6% HL), and from  H. raqueliaeby the number of predorsal scales (15-19 vs. 10-13) and by the number of cusps of first maxillary tooth (3 vs. 5).   Description.Morphometric data for  H. huambonicussummarized in Table 2. Largest male 87.0 mm SL, largest female 109.9 mmSL. Body compressed and elongate; greatest body depth at vertical through middle length of pectoral fins. Dorsal profile of head nearly straight to slightly convex. Dorsal body profile convex from occipital bony to base of last dorsal-fin ray; straight from this point to adipose-fin origin. Ventral profile of head slightly convex. Ventral body profile convex from pectoral-fin origin to pelvic-fin origin and straight to anal-fin origin. Body profile along anal-fin base posterodorsally slanted. Caudal peduncle elongate, nearly straight to slightly concave along dorsal and ventral margins. Snout rounded from margin of upper lip to vertical through anterior nostrils. Head heavy (massive) and relatively small. Mouth terminal, mouth slit nearly at horizontal through below middle of eye. Maxilla long and slightly curved, aligned at angle of approximately 45º to longitudinal body axis, and its posterior tip extending below orbit, reaching nearly to vertical through center of eye.   Table 2.Morphometric data of syntype of  Hemibrycon huambonicus(S, NMW 57531) from Huambo, Peru, non-types from the upper río Huallaga basin (CAS 70082, 70085, 70089, 70091-93; ICNMHN 7317), and from the upper río Marañon basin (CAS 70083, 70086; ROM 55238, 55406, 55366); and holotype (H, MUSM 35491) and paratypes of  Hemibrycon inambarifrom the upper río Madre de Dios basin (ANSP 143290, 143293, 143307,143291, 143294, 143300, 143306,143312,143317, 151478, 151497,151526,MCP 45753, MUSM 26299, 26776, 26802, UFRGS 13201). The range includes the holotype. m, males; f, females. SD = Standard deviation.    S   H. huambonicus   H. inambari  n Río Huallaga basin Río Marañon basin Río Madre de Dios basin  Range Mean SD n Range Mean SD H n Range Mean SD  Standard length (mm) 87.0 63 39.5-109.9 69.5 - 86 32.0-107.1 69.9 - 65.4 52 32.3-87.3 51.7 -  Percents of Standard length  Predorsal distance 52.5 63 26.4-54.9 51.0 3.5 86 45.6-55.2 50.6 1.9 51.9 52 48.6-54.8 52.0 1.4  Prepelvic distance 43.1 63 39.6-47.0 43.5 1.7 86 38.0-46.7 42.0 2.0 41.8 52 40.4-47.6 44.2 1.7  Prepectoral distance 22.9 63 21.7-27.3 23.9 1.1 86 19.8-25.9 22.2 1.2 21.2 52 19.9-25.9 23.1 1.5  Preanal distance 55.7 63 54.1-62.2 58.0 1.9 86 51.5-61.3 56.9 2.4 56.8 52 54.8-63.1 58.8 1.8  Depth at dorsal-fin origin (m) 32.2 16 29.7-34.1 31.4 1.4 41 27.3-32.6 29.5 1.2 31.1 14 29.1-32.7 31.2 1.0  Depth at dorsal-fin origin (f) - 47 28.9-35.8 32.0 1.5 43 29.3-34.9 31.8 1.1 - 38 28.7-35.3 32.0 1.4  Caudal peduncle depth 16.2 16 11.2-15.1 12.8 0.7 86 10.7-13.6 12.3 0.6 13.0 52 11.1-14.6 12.8 0.6  Caudal peduncle length 15.5 47 13.5-17.9 15.4 1.0 86 13.2-18.7 15.7 1.1 13.7 52 10.9-15.6 13.9 1.0  Anal-fin base 33.4 63 26.3-36.1 30.9 1.8 86 27.1-37.7 32.1 2.1 32.9 52 28.0-34.4 31.2 1.6  Dorsal-fin length 24.1 63 22.0-26.3 23.7 1.0 85 20.4-26.9 23.3 1.3 22.9 52 21.0-25.3 23.1 1.0  Pelvic-fin length (m) 16.2 16 14.1-17.3 15.2 0.8 42 14.2-17.4 15.7 0.7 12.3 14 11.2-13.8 12.3 0.6  Pelvic-fin length (f) - 47 12.7-17.0 14.5 0.9 44 12.7-15.8 14.2 0.7 - 38 11.2-13.6 12.7 0.6  Pectoral-fin length (m) 22.6 16 20.8-23.4 21.8 0.7 42 18.9-23.3 20.7 0.9 19.0 14 17.7-22.7 19.4 1.1  Pectoral-fin length (f) - 47 19.7-25.3 22.0 1.0 44 18.7-22.6 20.4 0.9 - 38 18.6-23.0 20.7 1.2  Head length 23.5 63 22.0-26.0 24.2 1.0 86 19.7-25.4 22.4 1.1 22.2 52 20.6-26.3 23.5 1.6  Percents of Head length  Snout length 21.5 63 17.7-24.3 21.6 1.1 86 19.0-25.8 21.8 1.2 21.0 52 18.5-23.6 21.3 1.1  Upper jaw length 45.5 63 45.2-52.6 48.5 1.8 86 39.5-48.9 44.7 1.6 43.1 52 43.1-50.7 47.2 1.8  Orbital diameter 25.4 63 24.2-33.9 29.1 2.4 86 26.0-35.3 30.7 2.2 29.3 52 27.1-37.9 32.8 2.9  Interorbital width 35.5 63 31.0-39.2 34.5 1.7 86 28.1-39.2 33.7 2.1 33.1 52 29.3-36.2 33.1 1.4 Premaxilla with two tooth rows; outer row with 4-6, tricuspid teeth with central cusp slightly longer; inner row with 4 pentacuspid teeth, gradually decreasing in length from first to third teeth and last tooth smallest; central cusp twice or three times longer and broader than other cusps. Maxilla almost fully toothed with 7-13 uni- to tricuspid teeth, with central cusp longer. Three anteriormost dentary teeth larger, with 5 cusps, followed by medium sized tooth with 3-5 cusps, and 7-10 teeth with 1-3 cusps or conical; central cusp in all teeth two to three times longer and broader than other cusps. Cusp tips slightly curved posteriorly and lingually ( Fig. 9). Dorsal-finraysii,8 (n= 64); firstunbranchedrayapproximately one-half length of second ray. Dorsal-fin origin located approximately to middle of SL and posterior to vertical through pelvic-fin origin. Males with bony hooks in distal one-third of first branched rays. Profile of distal margin of dorsal fin nearly straight to slightly concave. Adipose-fin located at vertical through insertion of two last anal-fin rays.Anal-fin rays iii-v,22- 27 (mode = 24, n = 64, Fig.2).Anal-fin profile slightly concave in males and nearly straight in females.Anal-fin origin approximately at vertical through insertion in the last dorsal fin rays. Anal-fin rays of males bearing one pair of developed bony hooks along posterolateral border of each segment of lepidotrichia, usually along last unbranched ray and first twelve branched rays. Only two males( syntypeand non-type male) possess bony hooks in all anal-fin rays. Hooks usually located along posteriormost branch and distal 1/ 2 to 2/ 3 of each ray. Pectoral-fin rays i,10-12 (mode = 11, n = 64). Pectoral-fin tip surpassing pelvic-fin origin in males, and reaching in females. Males with bony hooks on distal portion of unbranched and all branched rays. Pelvic-fin rays i,6,i or i,7 (n = 64). Pelvic-fin origin located 4-5 predorsal scales anterior to vertical through dorsal-fin origin. Pelvic fin of males usually bearing one small bony hook per segment of lepidotrichia along ventromedial border of all branched rays. Caudal fin forked with 19 principal rays (n = 64); lobes in similar size. First third of caudal-fin scaled. Dorsal procurrent rays 11 and ventral procurrent rays 11-12 (n = 4). Scales cycloid, moderately large. Lateral line complete with 44-48 (mode = 45, n = 64, Fig. 3). Scale rows between dorsal-fin origin and lateral line 8-10 (mode = 9, n = 64); scale rows between lateral line and pelvic-fin origin 6-7 (mode = 7, n = 64). Predorsal scales 15-19, arranged in regular series (mode = 17, n = 62). Scales rows around caudal peduncle 18-20 (n = 64). Axillary scale on pelvic-fin origin extends posteriorly covering 2-3 scales. Scale sheath along anal-fin base with 17-26 scales in single series, extending to base to 18 thto 24 thbranched rays. Precaudal vertebrae 20-21; caudal vertebrae 22-24; total vertebrae 42-43 (x-ray of syntype).Supraneurals 8-9.Gill rakers on upper limb of outer gill arch 7-8,and on lower limb 11-12 (n = 12).  Color in alcohol.General ground body color brown yellowish. Dorsal portion of head and body with concentration of black chromatophores. Dorsolateral portion of head and body with scattered black chromatophores. One vertical black humeral spot, located over fourth to sixth lateral line scales and extending over 5-6 horizontal series of scales, including lateral line. Caudal peduncle and middle caudal-fin rays dark pigmented.Abdominal region almost devoid of black chromatophores. Dorsal, adipose and caudal fin with dark pigmentation diffuse, and pectoral and pelvic fins hyaline ( Fig. 8).   Fig. 8.  Hemibrycon huambonicus, ROM55406, male, 73.3 mm SL, upper río Ucayali basin, Peru.  Sexual dimorphism.Males of  Hemibrycon huambonicusare easily recognized by the presence of bony hooks in dorsal, anal, pelvic and pectoral fin rays. Males and females also slightly differ in pectoral- and pelvic-fin lengths and body depth ( Table 2), and in anal-fin shape, slightly concave in males and nearly straight in females. Mature males with gill gland on first gill arch, covering the first branchial filaments ( Fig. 7).   Distribution.  Hemibrycon huambonicusis known from río Huambo, río Crisnejas and río Tingo, all tributaries of río Huallaga drainage, and río Marañon drainage, upper río Amazonas basin, Peru( Fig. 4).   Remarks.The original description of  H. huambonicusprovided by Steindachner (1882)is relatively brief, with the typelocality reported only for Huambo ( Peru). In Peru, there are two possible localities for Huambo: (1) río Huambo, San Martin, Peru, ca. 07º04’S 77º10’W, upper río Huallaga drainage, and (2) río Huambo, Huanuco, ca. 09º39’S 74º56’W, río Pachitea and río Ucayalidrainage. All lots analyzed and identified as  H. huambonicusare from río Huallaga and río Marañon drainages. (= río Higueros) into río Huallaga from the NW at Huanuco, Huanuco, ca. 09º55’S 76º13’W, 16-25 Oct 1918. CAS 70090, 24, 43.0- 85.3 mmSL, CAS 70091, 89, 42.7-94.4 mmSL, Huancachupa creek, a tumultuous small stream from the eastern slope of the central cordillera to río Huallaga a league above Huanuco, ca. 6,000 ft.elev., Huanuco, ca. 09º55’S 76º13’W, 16-25 Oct 1918. CAS 70092, 14, 42.0- 73.1 mmSL, large creek/small river arising from río Huallaga above Cayumba rapids, Chumatagua, ca. 09º27’S 75º58’W, 1 Oct 1918. CAS 70093, 6 of 7, 37.1-84.3 mmSL, Chachara and Ford on lower río Chinchao (into río Huallaga above Cayumba rapids), Pedra Blanca, ca. 09º27’S 75º58’W, 2 Oct 1918. ICNMHN 7317, 73, 32.6-109.9 mmSL, provincia de Leoncio Prado, Parque Nacional Tingo Maria, Huanuco, ca. 09º18’S 75º59’W, May 2003. MUSM 10565, 2 of 3, Huanuco, río Huallaga, río Cayumba, río Marañon drainage, km 495, 09º32’00”S 76º00’00”W, 29 Sep 1996. Río Marañon drainage:CAS 44355, 1, 57.9 mmSL [listed as  H. helleriby Eigenmann (1927: 406)], río Crisnejas near its junction with upper río Paipay, at Paipay, Cajamarca, ca. 07º25’S 78º10’W, Geographic variation.The population of  H. huambonicusfrom río Marañon drainage has head length slightly smaller (19.7-25.4 vs. 22.0-26.0% SL), and upper jaw length smaller (39.5-48.9 vs. 45.2-52.6% HL) than the population from río Huallaga drainage. However, no other significant difference was found between these populations for the recognition of a distinct species.   Material examined.   Syntype. NMW 57531, male(x-ray), 87.0 mm SL, Huambo, Peru[ río Huambo, Huanuco, ca. 09º39’S 74º56’W, río Pachiteaand río Ucayali drainage].  Non-type specimens.  Peru. Río Huallaga drainage: CAS 70082, 5, 64.1-95.2 mmSL, río Huallagaat Ambo(or Tambo), ca.  7,500 ft.elev., Huanuco, ca. 10º08’S 76º10’W,  26-29 Oct 1918.  CAS 70085, 6, 59.9-86.1 mmSL, río Huallagaat Huanuco, ca.  6,000 ft.elev., Huanuco, ca. 09º55’S 76º13’W  Oct 1918.  CAS 70089, 51, 30.7-81.2 mmSL, río Tingo  Aug 1923.  CAS 70083, 2, 52.5-53.5 mmSL, on the intercordilleran río Marañonat  3,500 ft.elev., Balsas, Amazonas, ca. 06º50’S 77º58’W,  Jul 1923.  CAS 70086, 25, 52.6-82.4 mmSL, Cajamarca, río Paipayinto río Crisnejasnear its junction with upper río Marañon, ca. 07º20’S 77º45’W, small deeply entrenched stream ca.  4,000 ft.elev.,  Jul 1923.  ROM 52238, 40of 85, 25.6-94.5 mmSL, ca.  74 kmW of road going Nto Jean, between Pucaraand Guabel, Huancabamba Rivertributary, río Marañon drainage, 05º56’00”S 79º15’00”W,  8 Jul 1986.  ROM 55366, 21of 47, 24.6-62.1 mmSL, ca.  14 kmWof Bagua, Marañon Rivertributary, 05º41’00”S 78º39’00”W,  1 Jul 1986.  ROM 55406, 60of 603 (3 c&s), 35.1- 105.6 mmSL,  2 kmNWfrom the junction of the road to Chachapoyasand the road to Bagua, Utcubamba Rivertributary, río Marañon drainage, 06º13’00”S 77º54’00”W,  29 Jun 1986. 5904933400 NMW Peru -9.65 rio Huambo 1299 -74.933334 Huambo 9 746 57531 1 Huanuco syntype 5904933343 1918-10-26 1918-10-29 1918-10-26 CAS Peru rio Huallaga 2286 -9.916667 Rio Huallaga drainage 1298 -76.21667 Ambo 9 746 70082 5 Huanuco 5904933350 1918-10 1918-10-29 1918-10 CAS Peru rio Huallaga 1829 -9.916667 rio Huallaga 1298 -76.21667 Ambo 9 746 70085 6 Huanuco 5904933378 1923-08 1918-10-29 1918-10 CAS Peru rio Huallaga 2286 10 747 -9.916667 rio Tingo 1298 -76.21667 Ambo 9 746 70089 51 Huanuco 5904933340 1923-07 CAS 1067 -6.8333335 rio Maranon 1303 -77.96667 Balsas 10 747 70083 2 Amazonas 5904933349 1923-07 CAS, 25 Jean 1219 -7.3333335 rio Paipay 1303 -77.75 rio Paipay 10 747 70086 1 Cajamarca 5904933418 1986-07-08 ROM Jean -5.9333334 Huancabamba River 21 -79.25 Pucara 10 747 52238 40 Maranhao 5904933451 1986-07-01 ROM Chachapoyas -5.6833334 Maranon River 21 -78.65 Bagua 10 747 55366 21 Maranhao 5904933427 1986-06-29 ROM Chachapoyas -6.2166667 Utcubamba River 21 -77.9 Bagua 10 747 55406 60 Maranhao