Hemibrycon beni Pearson, 1924: 42-43 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 4 737 737 3KLYY Pearson, 1924 Pearson 1924 [278,636,1537,1561] Actinopterygii Characidae Hemibrycon Animalia Characiformes 2 Chordata species beni    Fig. 1      Hemibrycon beni  Pearson, 1924: 42-43(original description; typematerial; typelocality: Espiaand río Colorado, lower Bopi, Bolivia), 62-63 (pl. 2, fig. 6, cotype).   Diagnosis.  Hemibrycon beniis readily distinguished from most congeners, except  H. mikrostiktos,  H. paez,  H. tridens, and  H. virolinica, by the number of branched anal-fin rays (15-19 vs. 20-34, Fig. 2).  Hemibrycon benidiffers from these species by the number of lateral line scales (44-53 vs. 40-42, 39-42, 39, and 40-44, respectively). Furthermore,  H. benidiffers from  H. virolinicaby the number of predorsal scales (17-20 vs. 10-15). The branched anal-fin ray counts of  H. benioverlapping somewhat the  H. hellericounts (15-19 vs. 19-23), but they can be distinguished further by the size of humeral spot (3-4 vs. 7-8 horizontal series of scales), and by total number of vertebrae (38-39 vs. 41-43).   Description.Morphometric data for  H. benisummarized in Table 1. Largest male 81.4 mmSL, largest female 34.3 mmSL. Body compressed and moderately elongate; greatest body depth usually at vertical through middle length of pectoral fins. Dorsal profile of head straight to slightly convex. Dorsal body profile convex from occipital bone to base of last dorsalfin ray; straight from this point to adipose-fin origin. Ventral profile of head convex. Ventral body profile convex from pectoral-fin origin to pelvic-fin origin, and straight to slightly convex 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 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. Premaxilla with two teeth rows; outer row with 4-5 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 fully toothed, with 7-14 uni- to tricuspid teeth, with central cusp longer. Three anteriormost dentary teeth larger, with 3-5 cusps, followed by medium sized tooth with 3 cusps, and 8-9 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. Dorsal-fin rays ii,8 (one with ii,7 and one with iii,8; n = 30); first unbranched ray approximately one-half length of second ray. Dorsal-fin origin located posterior to middle of SL and posterior to vertical through pelvic-fin origin. Profile of distal margin of dorsal fin convex. Dorsal fin without bony hooks. Adipose-fin located at vertical through insertion of last or posterior to last anal-fin ray. Anal-fin rays iii-iv,16-18 (one with 15 and two with 19, mode = 17, n = 35, Fig. 2). Anal-fin profile slightly convex 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 small bony hooks along posterolateral border of each segment of lepidotrichia, usually along last unbranched ray and third to fourth branched rays. Hooks usually located along posteriormost branch and distal 1/ 2 to 2/ 3 of each ray. Pectoral-fin rays i,10-11 (mode = 10, n = 33). Pectoral-fin tip reaching pelvic-fin origin in all specimens. Pectoral fin without bony hooks. Pelvic-fin rays i,6,i (one with i,5,i, n = 33). Pelvicfin origin located 5-6 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 second to eighth branched rays. Caudal fin forked with 19 principal rays without bony hooks 740 A review of the Cis-Andean species of  Hemibrycon   Fig. 1.  Hemibrycon beni, CAS44333, syntype, male, 56.0 mm SL, upper río Beni basin, Bolivia. (n = 33); lobes similar in size. Caudal-fin base with a few scales in half-length, followed by one large scale in each lobe. Caudal fin without bony hooks. Dorsal procurrent rays 10-11 and ventral procurrent rays 11 (n = 2, x-ray). Scales cycloid, moderately large. Lateral line complete with 44-53 (mode = 45, n = 32, Fig. 3). Scale rows between dorsalfin origin and lateral line 7-8 (mode = 8, n = 33); scale rows between lateral line and pelvic-fin origin 6-8 (mode = 7, n = 33). Predorsal scales17-20, arranged in regular series (mode = 18, n = 33). Scales rows around caudal peduncle 16-18 (mode = 16, n = 32).Axillary scale on pelvic-fin origin extends posteriorly covering two scales. Scale sheath along anal-fin base with 5-8 scales in single series, extending to base of most anterior branched rays. Precaudal vertebrae 18-19; caudal vertebrae 20; total vertebrae38-39 (n = 3). Supraneurals 7 (n = 1, x-ray).Gill rakers on upper limb of outer gill arch 6, and on lower limb 10-11 (n = 4).  Color in alcohol.Dorsal portion of head and body dark brown. Dorsolateral portion of body with scattered black chromatophores. Midlateral body silvery. One small and vertical black humeral spot, located over third to fourth lateral line scales and extending over 1-2 horizontal series of scales including lateral line, and sometimes over the first horizontal series below lateral line. Base of caudal fin and middle rays black pigmented. Abdominal region almost devoid of black chromatophores. Dorsal, adipose, and caudal fin with dark brown pigmentation diffuse and anal fin with small black chromatophores along its border forming narrow stripe. Caudal peduncle without spot. Pectoral and pelvic fins hyaline ( Fig. 1). Body yellowish.  Sexual dimorphism.Males of  Hemibrycon beniare easily recognized by the presence of bony hooks on the anal- and pelvic-fin rays. Males and females also slightly differ in body   Fig. 2.Tukey box plots of number of branched anal-fin rays in  Hemibryconspecies.Mean represented by thick vertical bar, and 25 thand 75 thpercetiles as lateral borders of box plots. Number in parentheses = N.   Fig. 3.Tukey box plots of number of lateral line scales in  Hemibryconspecies.Mean represented by thick vertical bar, and 25 thand 75 thpercetiles as lateral borders of box plots. Number in parentheses = N.  V. A. Bertaco & L. R. Malabarba741   Table 1.Morphometric data of syntypes of  Hemibrycon beni(CAS 44333, 44334; USNM 117543) from río Beni basin, Espia, La Paz, Bolivia, and paratypes of  Hemibrycon helleri(CAS 44354; FMNH 58439), and non-types from río Urubamba basin (ANSP 180775, 180777; CAS 70077). m, males; f, females. SD = Standard deviation.      H. beni   H. helleri  Syntypes Paratypes Non-types  n Range Mean SD n Range Mean SD n Range Mean SD  Standard length (mm) 30 29.0-81.4 45.5 - 8 36.4-78.6 53.9 - 11 43.3-81.6 60.9 -  Percents of Standard length  Predorsal distance 30 51.8-58.6 54.9 1.7 7 50.8-52.7 52.0 0.8 11 50.5-54.2 52.9 1.2  Prepelvic distance 30 41.2-51.0 45.9 1.9 7 43.1-47.9 44.9 1.5 10 42.9-47.0 45.4 1.1  Prepectoral distance 30 23.0-28.7 25.7 1.2 7 22.1-25.4 23.7 1.1 10 21.4-26.7 23.5 2.0  Preanal distance 30 60.9-67.8 63.3 1.6 7 59.2-61.2 60.2 0.9 11 57.9-63.9 61.4 1.8  Depth at dorsal-fin origin(m) 23 29.6-35.6 32.3 1.7 2 30.6-30.9 30.7 0.2 2 28.7-29.6 29.2 0.8  Depth at dorsal-fin origin(f) 7 29.4-33.1 31.2 1.1 6 29.3-34.5 32.1 1.8 8 28.5-32.4 30.8 1.4  Caudal peduncle depth 30 10.6-14.6 12.7 1.0 8 11.9-14.3 12.7 0.7 11 10.5-13.3 12.2 0.7  Caudal peduncle length 30 14.0-19.6 17.9 1.4 8 12.4-17.0 15.6 1.5 11 14.3-16.4 15.3 0.7  Anal-fin base 30 19.1-25.0 22.1 1.4 8 27.3-29.3 28.2 0.6 11 25.1-29.6 27.2 1.4  Dorsal-fin length 30 21.6-26.7 24.0 1.2 8 20.8-24.6 22.2 1.3 5 20.4-22.7 21.4 0.9  Pelvic-fin length (m) 23 14.8-18.2 16.3 0.9 2 11.8-13.0 12.4 0.8 2 13.1-13.3 13.2 0.1  Pelvic-fin length (f) 7 14.0-15.3 14.8 0.5 6 13.5-14.3 13.9 0.3 3 13.1-14.5 13.7 0.4  Pectoral-fin length (m) 23 18.8-22.1 20.4 0.8 2 18.7-20.2 19.4 1.0 2 20.2-20.2 20.2 0.0  Pectoral-fin length (f) 7 20.4-21.8 21.3 0.6 6 19.7-21.7 20.5 0.7 3 20.4-21.5 20.8 0.5  Head length 30 24.1-28.8 26.2 1.2 7 22.4-25.1 23.6 0.8 11 21.9-25.3 23.5 0.9  Percents of Head length  Snout length 30 20.0-26.0 22.7 1.1 7 19.9-24.6 22.1 1.5 11 19.7-23.0 21.4 1.0  Upper jaw length 29 40.8-53.2 47.1 2.1 7 42.1-47.6 45.4 1.8 11 43.2-49.3 46.0 1.8  Orbital diameter 30 25.4-38.2 30.7 2.4 7 28.4-33.5 31.1 1.7 11 25.4-32.0 28.9 2.4  Interorbital width 30 29.1-35.3 31.9 1.3 7 30.9-33.7 32.2 1.1 11 30.5-38.3 33.9 2.1 depth ( Table 1), and in anal-fin shape, which is slightly convex in males and nearly straight in females. Gill glands were not found on first gill arch in either males or females.   Distribution.  Hemibrycon beniis known from río Benidrainage, upper río Madeira basin, where ríos La Pazand Miguilla join to form río Bopi, Espia, La Paz, Bolivia( Fig. 4).   Remarks.  Hemibrycon beniwas described by Nathan Pearson based on specimens collected by the Mulford Expedition, Bolivia, in 1921. In the original description, Pearson designated 48 “cotypes” in good condition plus 58 “dried during shipment”, all specimens catalogued under IU 17321, and further listed six specimensnot identified as types (IU 17347, now CAS 44335). Of the original 106 cotypes under IU 17321, however, there are 107 presently catalogued as cotypes under CAS 44333, 29 specimens, CAS 44334, 60 specimens, USNM 117543, 2 specimens, and UMMZ 66504, 16 specimens. This last lot was not examined. All specimens of the lot CAS 44334 are very dry but the remaining syntypesare in good condition.   Material examined.   Syntypes. CAS44333, 29(1 x-ray), 24.1- 56.0 mm SL,  CAS44334, 60, 27.4-81.4 mmSL,  USNM 117543, 2(x-ray), 31.6-42.1 mmSL, where ríos La Pazand Miguillajoin to form río Bopi, río Benidrainage, elev.  3,080 ft., Espia, La Paz, Bolivia, ca. 16º16’S 67º12’W,  Jul 1921, N. E. Pearson. Non -type specimens.  CAS44335, 6, 22.5-24.8 mmSL, río Colorado, tributary to lower río Bopi  10 miabove Huachi, Mulford Explorationof the Amazon Basin, La Paz, Bolivia, ca. 16º05’S 67º12’W,  Sep 1921. [324,549,1633,1656] Bolivia lower Bopi Espia rio Colorado 2 2 CAS 44333 CAS 4 29 1 syntype CAS 44334 [946,1278,1475,1496] CAS 4 60 1 syntype 1921-07 USNM Bolivia Espia 939 -16.266666 Miguilla 1282 -67.2 rio Bopi 4 USNM 117543, 2 1 La Paz syntype CAS 44335 1921-09 CAS Bolivia Amazon Basin -16.083334 rio Colorado 1283 -67.2 Mulford Exploration 4 6 1 La Paz syntype