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Hemigrammus changae, new species (Figs. 1–3) Hemigrammus cf. lunatus (not Durbin): Mirande, 2018: 9 (phylogenetic relationships; based on a specimen from lot MUSM 3927). Holotype: MUSM 663836, 29.9 mm SL, Peru, Departamento Madre de Dios, Puerto Maldonado, Aguajal Cicra, Aguajal Pozo Minero, 12 o 33'48"S 70 o 07'03"W, 9 Dec 2003, M.H. Hidalgo. Paratypes: All from Peru. Departamento Madre de Dios: MUSM 21644, 34, 1 c&s, 22.3–28.7 mm SL; CAS 246141, 10, 23.1 – 27.6 mm SL; FMNH 138666, 10, 24.1 – 27.8 mm SL; MCZ 173322, 8, 24.1 – 27.1 mm SL; ZUEC 17027, 10, 23.5 – 26.7 mm SL; same data as holotype. MUSM 3927, 151, 3 c&s, 16.0–24.0 mm SL; ZUEC 17029, 7, 3 c&s, 19.1–22.3 mm SL, Zona Reservada Tambopata Candamo, La Colpa, cocha tributary of río Tambopata, ca. 12°55'S 69°15'W, 22 Aug 1992, F. Chang & J. Icochea. MUSM 5600, 14, 21.0– 26.4 mm SL, Zona Reservada Tambopata Candamo, Las Piedras, quebrada 2 km from lago Sandoval, ca. 12°36'S 69°03'W, 23 Jan 1990, H. Ortega, F. Chang & F. Rodriguez. MUSM 8563, 9, 19.5 – 23.8 mm SL, Puerto Maldonado, La Cachuela, 12°34'45"S 69°11'13"W, 12 March 1995, H. Ortega. MUSM 21701, 18, 10.8 – 26.3 mm SL, Puerto Maldonado, Aguajal Satélite, Aguajal Aguas Negras, 12°39'26"S 69°26'29"W, 22 Jan 2004, M.H. Hidalgo. MUSM 21823, 58, 10.2 – 27.9 mm SL, Puerto Maldonado, Aguajal Aguas Negras, Aguajal Pozo Minero, 12 o 38'10"S 69 o 25'36"W, 21 Jan 2004, M.H. Hidalgo. INPA 57938, 10, 4 c&s, 23.6–28.0 mm SL; MUSM 21992, 126, 10.5 – 29.3 mm SL; MUSM 22018, 83, 12.2 – 30.4 mm SL, Puerto Maldonado, Aguajal Este, lower río Madre de Dios, San Francisco, 12 o 28'11"S 68 o 56'04"W, 20–21 Feb 2004, M.H. Hidalgo. MUSM 22055, 27, 16.0– 30.3 mm SL; MUSM 22068, 149, 10.6 – 29.6 mm SL; ZUEC 17028, 4, 19.1 – 29.7 mm SL, Puerto Maldonado, Puerto Pardo, Aguajal Tripa, lower río Madre de Dios, 12°29'34''S 68°57'31''W, 22–23 Feb 2004, M.H. Hidalgo. MUSM 22135, 40, 9.8 – 27.3 mm SL, Puerto Maldonado, San Francisco, Aguajal Trigoso, lower río Madre de Dios, 12 o 27'58"S 68 o 52'53"W, 28 Feb 2004, M.H. Hidalgo. MUSM 22040, 58, 13.5 – 25.3 mm SL, Puerto Maldonado, San Francisco, Aguajal Pozo Paiche, lower río Madre de Dios, 12 o 29'05"S 68 o 57'09"W, 22 Feb 2004, M.H. Hidalgo. Departamento Puno: MUSM 52037, 1, 21.9 mm SL, Cocha Wiener, río Heath, 13 o 19'11"S 68 o 52'32"W, 18 Jun 2013, J. Chuctaya et al. Non-types: Peru, Departamento Madre de Dios: MUSM 2919, 24, 14.8 – 23.5 mm SL, Zona Reservada Tambopata Candamo, La Colpa, Quebrada Grande, tributary of río Tambopata, ca. 12°55'S 69°15'W; 31 Aug 1992, F. Chang. MUSM 22094, 10, 10.3 – 13.5 mm SL, Puerto Maldonado, Aguajal Oeste, tributary of río Madre de Dios, 12°28'40"S 68°58'18"W, 25 Feb 2004, M.H. Hidalgo. MUSM 22112, 25, 14.1 – 19.1 mm SL, Puerto Maldonado, Aguajal Gamitana, 12°27'08"S 69°00'32"W, 26 Feb 2004, M.H. Hidalgo. MUSM 25387, 41, 16.5 – 32.1 mm SL, Tahuamanu, río Manuripe, Cocha Macana, ca. 11°49'S 69°32'W, 12 Jul 2004, M.H. Hidalgo et al. MUSM 52701, 1, 20.4 mm SL, Mavila, cocha tributary of río Manuripe, 11°55'37"S 69°06'51"W, 23 Jul 2003, M.H. Hidalgo et al. MUSM 52699, 1, 25.5 mm SL, Manu, Quebrada Carachama, tributary of río Amiguillos, tributary of río Los Amigos, 12°26'40"S 70°15'43"W, 19 Jun 2004, M.H. Hidalgo et al. Bolivia, Departamento Beni: USNM 305661, 7, 20.9 – 22.3 mm SL, Arroyo Aguas Negras, tributary of río Curiraba, 3 km above mouth, 12 km N El Porvenir Biological Station, 40 km E San Borja, río Mamoré basin, ca. 14°55'S 66°17'W, 1 Sep 1987, W.C. Starnes & T. Munroe. MHNG 2228.086, 8, 22.0–25.0 mm SL, tributary of río Chapare, 50 km from confluence with río Mamoré, ca. 15°22'S 65°2'W, 21 Jun 1982, L. Lauzanne & G. Loubens. Departamento Cochabamba: MHNG 2180.097, 5, 23.6 – 27.8 mm SL, río Chapare, "Hoffman Lagune" below Todos Santos, ca. 16°50'S 65°17'W, 7 Oct 1966, K.H. Lüling. Departamento Santa Cruz: MHNG 2228.075, 2, 11.3 – 19.5 mm SL, río Yapacani, near Yapacani, tributary of río Grande, ca. 17°23'S 63°51'W, Sep 1983, W. Staeck & H. Linke. MHNG 2270.056, 2, 21.5 – 23.8 mm SL, same locality and collectors as MHNG 2228.075, 19 March 1985. Diagnosis. Hemigrammus changae differs from most congeners except from H. barrigonae, H. lunatus, H. machadoi, and H. ulreyi by possessing a wide dark horizontal stripe across the eye (vs. eye stripe absent or, when present, vertical). The new species can be additionally distinguished from all congeners, with the exception of Hemigrammus barrigonae, H. boesemani, H. geisleri, H. lunatus, H. machadoi, H. mimus, and H. ulreyi, by presenting a well-defined narrow dark stripe at the basis of the anal fin (vs. absence of dark stripe at the basis of anal fin). It can be distinguished from H. boesemani, H. geisleri, and H. mimus by lacking a blotch on caudal peduncle or any distinct patch of pigmentation on caudal fin (vs. a dark blotch on caudal peduncle or at the base of caudal fin present). Hemigrammus changae can be additionally diagnosed from Hemigrammus geisleri and H. mimus by lacking a pseudotympanum (vs. presence of a conspicuous pseudotympanum). The new species can be diagnosed from H. barrigonae, H. lunatus, and H. machadoi by presenting an oval, horizontally elongated humeral blotch (vs. a diffuse, vertically-elongated humeral blotch in H. barrigonae; a small rounded humeral blotch in H. lunatus; a rectangular, vertically-elongated blotch in H. machadoi). Hemigrammus changae can be distinguished from H. ulreyi by the absence of a patch of dark pigmentation on the basis of anteriormost dorsal-fin rays (vs. presence of a patch of dark pigmentation on the basis of anteriormost dorsal-fin rays). The new species can be additionaly distinguished from H. ulreyi, as well as from H. barrigonae, by lacking a conspicuous midlateral stripe (vs. presence of a conspicuous midlateral stripe). Hemigrammus changae can be additionally diagnosed from H. machadoi by presenting 6–7 gill-rakers on upper branch and 10–12, mode 12, on lower (vs. 4–5, and 9–10, mode 9, respectively), and more vertebrae (34–35 vs. 32–33), and from H. lunatus by presenting a higher number of cusps on maxillary largest tooth (5 vs. 1–3). Description. Morphometric data summarized in Table 1. Body compressed, moderately high; greatest body depth anterior to dorsal-fin origin. Dorsal profile of head slightly convex from tip of snout to anterior naris; straight to gently concave from latter point to tip of supraoccipital spine. Dorsal profile of body slightly to moderately convex from tip of supraoccipital spine to dorsal-fin origin; posteroventraly slanted from latter point to adipose-fin origin and slightly concave along caudal peduncle. Ventral profile of body convex from tip of dentary to anal-fin origin, posteroventraly slanted along anal-fin base. Ventral profile of caudal peduncle slightly to moderately concave. TABLE I. Morphometric data of Hemigrammus changae, new species. N = Number of specimens, and SD = standard deviation; all including the holotype. Mouth terminal; jaws equal, isognathous. Maxillary slightly curved, distal tip extending beyond vertical through anterior margin of eye. Premaxillary teeth in two rows, outer row composed by 3*(40) or 4(18) tri- to pentacuspid teeth, central cusp longer; inner row with 5*(78) penta- to heptacuspid teeth teeth, central cusp longer. Maxillary with 2(8) to 3(1) tri- to pentacuspid teeth along anteroventral margin, anteriormost tooth broader and always pentacuspid. Dentary with 9(1), 10(1), 11(3), 12(2), 13(1), or 15(1) teeth, anteriomost four teeth larger than remaining, with 5–7 cusps, central cusp longer, then gradually decreasing in size, 1–2 pentacuspid teeth, and remaining 4–9 tri- or unicuspid, small teeth (Fig. 2). Scales cycloid. Lateral line incomplete, slightly curved ventrally, with 6(7), 7(9), 8*(15), 9(13), 10(8), or 11(2) pored scales; longitudinal series including perforated scales 29(1), 30(1), 31*(5), 32(8), 33(19), 34(13), or 35(7). Scales rows between dorsal-fin origin and lateral line 5*(54); 3*(23) or 4(31) between lateral line and pelvic-fin insertion. Predorsal scales 9(4), 10*(32), or 11(18). Anal sheath along anal-fin base with 5 or 6 scales in a single row, covering base of first unbranched to fourth branched anal-fin rays. Circumpeduncular scales 10(41), 11*(7) or 12(6). Caudal-fin scales covering approximately basal third of upper and lower caudal-fin lobes margins, gradually decreasing in size. Dorsal-fin rays ii,9*(54), first unbranched ray nearly one-third of second unbranched ray length; small ossification anterior to first unbranched ray present in all six c&s specimens examined. Dorsal-fin distal margin straight. Dorsal-fin origin at midbody or slightly behind this point; base of posteriormost dorsal-fin ray slightly behind vertical through anal-fin origin. Insertion of first dorsal-fin pterygiophore posterior to neural spine of 9th(6) vertebra. Adipose fin present. Pectoral-fin rays i,10*(52) or 11(1). Pelvic-fin rays i,7*(53), pelvic-fin origin ahead of vertical through dorsal-fin origin; tip of longest ray exceeding anal-fin origin. Anal-fin rays iv, 20(4), 21(4), 22*(11), 23(17), 24(15), or 25(2); last unbranched ray to fifth branched ray longest, remaining rays gradually decreasing in size to anal-fin terminus, forming a conspicuous anterior fin lobe. Last anal-fin pterygiophore insertion behind hemal spine of 14(1) or 15(5) caudal vertebrae. Caudal fin forked, lobes slightly pointed, equal in size. Principal caudal-fin rays i,17,i*(45); dorsal procurrent caudal-fin rays 10(4) or 11(3); ventral procurrent caudal-fin rays 7(2) or 8(5). Vertebrae 33(2) or 34(5). Supraneurals 4(6) or 5(1). Branchiostegal rays 4(5). Upper branch of gill-rakers 6(4) or 7(1), lower branch 10(9), 11(18) or 12(20). Color in alcohol. Overall body ground coloration light tan. Anterior portion of lower jaw, maxillary, first infraorbital, snout and dorsal portion of head with intense concentration of small dark chromatophores, imparting an overall darker color. Gular region and infraorbitals clearer; third infraorbital and opercle series silvery in specimens retaining guanine pigmentation. Opercle and infraorbitals with scattered, relatively large dark chromatophores. Eye with a broad dark longitudinal midlateral stripe (not discernible in specimens preserved for a long period in formalin). Longitudinal dark stripe along midline of body present, very faint and narrow, originating after small concentration of dark chromatophores posterior to humeral blotch and extending up to approximately vertical through middle of caudal peduncle or slightly behind this point. Scales from dorsal region of body, in some specimens almost all scales on body (Fig. 1C), posteriorly bordered with dark chromatophores, forming a subtle reticulate pattern. Dark humeral blotch conspicuous, roughly oval, extending horizontally from second through fifth lateral-line scales, and vertically from lateral line to one row above lateral line to one scale row above it. Dark chromatophores below midlateral line arranged along margins of hypaxial muscles bundles from area above anal fin to caudal peduncle. Narrow, very conspicuous dark stripe along anal-fin basis. Fins hyaline, with scattered dark chromatophores, more numerous on dorsal- and anal-fins. Color in life. Based on pictures of living specimens (not preserved) collected at the río Madre de Dios basin. Head and abdominal region silvery. Body olive-grey, translucent. A narrow midlateral iridescent green stripe, running from humeral blotch to caudal peduncle. Fins hyaline, with a yellow hue. Sexual dimorphism. Anal-fin hooks were observed in males of Hemigrammus changae collected in August (MUSM 3927, 1, 23.7 mm SL), December (ZUEC 17027, 4, 22.2–23.6 mm SL; FMNH 138666, 2, 24.0– 24.5 mm SL; MCZ 173322, 1, 23.5 mm SL; CAS 246141, 3, 23.5–24.0 mm SL), or February (INPA 57938, 2, 23.0– 23.1 mm SL; MUSM 22018, 5, 23.3–25.0 mm SL; and MUSM 22040, 2, 23.0– 23.3 mm SL). Anal fin with 7–11 tiny hooks, arranged over the last unbranched ray and anteriormost 3–5 branched fin rays, one pair per ray segment. Pelvic-fin hooks were not observed in any specimens. Larger specimens (equal or above 26.0 mm SL) always lack anal-fin hooks and presumably are all females, which consequently are inferred to grow larger than males (the largest specimen examined with anal-fin hooks has 25.0 mm SL, MUSM 22018). Distribution. Hemigrammus changae is so far known from the río Madre de Dios and from the río Mamoré basins, upper río Madeira basin, in southeastern Peru and Bolivia (Fig. 3). The new species is apparently endemic from the freshwater ecorregion Mamoré-Madre de Dios Piedmont (Abell et al., 2008). Ecological notes. Most localities from where Hemigrammus changae is known are slow-flowing streams at "aguajales" (wetlands dominated by Mauritia flexuosa palms). These streams typically possess black water, a large amount of decayed organic matter, and are typically shallow. The type locality was a former a gold mining area that is in the process of recovery due to the implantation of a private conservation concession. Hemigrammus changae is also recorded from oxbow lakes and, in Bolivia, from lakes and streams at the llanos (seasonally flooded savannahs). The species is sympatric, and in some localities syntopic with Hemigrammus lunatus, but the latter species is more commonly found in floodplain lakes from white water rivers, a type of habitat where H. changae is apparently uncommon. Etymology. The specific name honors the late Fonchii Ingrid Chang Matzunaga, a Peruvian ichthyologist, from Chinese and Japanese ancestry, born on April 30, 1963 in Lima, Peru, who drowned when the boat she was in capsized on August 15, 1999, during an expedition at río Pastaza, Peru. We dedicate to her the new species as a tribute for her considerable contribution in surveying the fishes of her native country, in the relatively little time she was active, which included collecting part of the material herein examined of H. changae. A genitive noun.

Atypical fish diversity gradients suggest a recent formation of the Amazon system such as we know it today., Using the most comprehensive fish occurrence database, we evaluated the importance of ecological and historical drivers in diversity patterns of subdrainage basins across the Amazon system. Linear models reveal the influence of climatic conditions, habitat size and sub-basin isolation on species diversity. Unexpectedly, the species richness model also highlighted a negative upriver-downriver gradient, contrary to predictions of increasing richness at more downriver locations along fluvial gradients. This reverse gradient may be linked to the history of the Amazon drainage network, which, after isolation as western and eastern basins throughout the Miocene, only began flowing eastward 1–9 million years (Ma) ago. Our results suggest that the main center of fish diversity was located westward, with fish dispersal progressing eastward after the basins were united and the Amazon River assumed its modern course toward the Atlantic. This dispersal process seems not yet achieved, suggesting a recent formation of the current Amazon system.

Initial Data Management Plan for the Amazonian Freshwater Fish Biodiversity database that will be constructed in the framework of the AMAZONFISH (ERANetLAC/DCC-0210) project.

International audience; Este libro es el resultado del Coloquio Internacional «Bergamín: entre literatura y política», organizado por las universidades Paris Ouest Nanterre La Défense y Autònoma de Barcelona. Participan destacados especialistas del escritor español José Bergamín, como Nigel Dennis, a quien rinde homenaje esta publicación. Dieciséis contribuciones conforman este volumen que propone, treinta años después de posarse sobre el poeta la mano de nieve, una reflexión sobre las dos grandes pasiones de su vida: la literatura y la política. A modo de anexo se incluyen las respuestas a la convocatoria «Un silencio por Bergamín», en la que han participado cerca de cuarenta escritores, artistas e investigadores.; Cet ouvrage collectif est le résultat du Colloque International « Bergamín: entre literatura y política », organisé par les universités Paris Ouest Nanterre La Défense et Autònoma de Barcelona, avec la participation des meilleurs spécialistes de l’écrivain espagnol José Bergamín, parmi lesquels Nigel Dennis, à qui cette publication rend hommage. L’ensemble des seize contributions recueillies propose, trente ans après la mort de cet important intellectuel du XXe siècle, une réflexion sur les deux grandes passions de sa vie : la littérature et la politique. En annexe, l’hommage « Un silencio por Bergamín » rassemble les contributions d’une quarantaine d’écrivains, artistes et chercheurs.

Hemibrycon divisorensis, new species Figs. 1-3 Holotype. MUSM 28860, 68.2 mm SL, male, Peru, Loreto, Requena, Zona Reservada Sierra del Divisor, upper r��o Tapiche, quebrada en la trocha 1, r��o Ucayali drainage, 07��12���02"S 73��53���00"W, 20 Aug 2005, M. Hidalgo & J. F. P. da Silva. Paratypes. MCP 41346, 4 (60.5-81.6 mm SL), 2 c&s (62.7-68.4 mm SL), MUSM 28040, 19, 35.0-73.0 mm SL, collected with holotype. MCP 41347, 5, 48.9 -65.0 mm SL, MUSM 28039, 11 (43.0- 58.0 mm SL), 1 c&s (55.9 mm SL), Peru, Loreto, Zona Reservada Sierra del Divisor, Ojo de Contaya, quebrada en la trocha 4, r��o Ucayali drainage, 07��06���54"S 74��35���08"W, 6 Aug 2005, M. Hidalgo & J. F. P. da Silva. Diagnosis. Hemibrycon divisorensis is distinguished from all other species of the genus by the presence of a wide black asymmetrical spot covering the base of caudal-fin rays and extending along entire length of caudal-fin rays 9 to 12-13 (except from H. surinamensis), and by the presence of a black band in the lower half of the caudal peduncle from the region above the last anal-fin rays to the caudal-fin base (Figs. 1-2). Furthermore, it is distinguished from most species of the genus by the number of the scale rows below lateral line (4-5 vs 5-9), except from H. jabonero, H. microformaa, H. orcesi, and H. surinamensis. Hemibrycon divisorensis differs from H. orcesi and H. microformaa by the higher number of lateral line scales (39-42 vs 34-35 and 33-37, respectively) and analfin rays (24-30 vs 18 and 14-16, respectively), and by color pattern; from H. jabonero and H. surinamensis by the higher number of scale sheath along anal-fin base (17-22 vs 8-14 and 15-16, respectively), and number of cusps in the inner row of the premaxilla teeth (5-7 vs 5, respectively). Description. Morphometric data for Hemibrycon divisorensis summarized in Table 1. Largest male 68.4 mm SL, largest female 81.6 mm SL. Body compressed and moderately elongate; greatest body depth usually nearly to dorsal-fin origin. Dorsal profile of head slightly convex to nearly straight. Dorsal body profile slightly convex from supraoccipital to dorsal-fin origin; posteroventrally slanted from dorsal-fin origin to adipose fin. Ventral profile of head slightly convex. Ventral body profile convex from isthmus to pelvic-fin origin, and straight to slightly convex from this point to anal-fin origin. Body profile along anal-fin base posterodorsally slanted. Caudal peduncle 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 middle of eye. Maxilla long, slightly curved, and aligned at angle of approximately 60 degrees to longitudinal body axis, with ventral border slightly convex to nearly straight and dorsal border slightly concave. Premaxilla with two tooth rows; outer row teeth 4-7 (6*), tricuspid to pentacuspid, central cusp slightly longer; inner row teeth 4, pentacuspid to heptacuspid, central cusp twice or three times longer and broader than other cusps, gradually decreasing in length from first to third teeth and last tooth smallest. Maxilla fully toothed with 10-13 (11*) tricuspid teeth with central cusp longer, except for last six or seven conical teeth. Three anteriormost dentary teeth larger, with 5-7 cusps, followed by medium sized tooth with 3-5 cusps, and 9-12 teeth with 2-3 cusps or conical; central cusp in all teeth two to three times longer and broader than other cusps (Fig. 3). All cusp tips slightly curved posteriorly towards inside of mouth. Dorsal-fin rays ii,8 (n = 19); first unbranched ray approximately one-half length of second ray. Dorsal-fin origin located slightly posterior to middle of SL and posterior to vertical through pelvic-fin origin. First dorsal-fin pterygiophore inserted between neural spines of 11 th to 12 th vertebrae (n = 3). Profile of distal margin of dorsal fin slightly concave or nearly straight. Males with bony hooks on distal one-third of first to fifth branched dorsal-fin rays. Adipose-fin located approximately at vertical through insertion of last four or five anal-fin rays. Anal-fin rays iv,25-28 (27*, rarely 24 or 29-30, mean = 26.7, n = 19). Anal-fin profile nearly straight in males and concave in females. Anal-fin origin approximately at vertical through insertion of last two or three dorsal-fin rays. First anal-fin pterygiophore inserted between hemal spines of first and second caudal vertebrae. Anal-fin rays of males bearing one pair of small bony hooks along posterolateral border of each segment of lepidotrichia, usually along first to 12 th anterior branched rays. Hooks more numerous along fourth through seventh branched rays, and usually located along posteriormost branch and distal 1/2 to 2/3 of each ray. Pectoral-fin rays i,10-13 (11*, mean = 11.1, n = 19). Pecto- ral-fin tip reaching pelvic-fin origin in males, not in females. Males with bony hooks on distal portion of unbranched and all branched pectoral-fin rays. Pelvic-fin rays i,6,i (n = 11) or i,7* (n = 8). Pelvic-fin origin located at vertical through 3-4 predorsal scales anterior to dorsal-fin origin. Pelvic fin of males usually bearing one small bony hook per lepidotrichia segment along ventromedial border of all branched rays. Caudal fin forked with 19 principal rays (n = 19); lobes similar in size. Basal portion of caudal-fin lobes covered with somewhat irregular scales and smaller than those of body, following by one larger and round shaped scale in each lobe. Dorsal procurrent rays 11 and ventral procurrent rays 10-11 (n = 3). Scales cycloid, moderately large. Lateral line complete with 39-41 scales (41*, one specimen with 42, mean = 40.2, n = 19). Scale rows between dorsal-fin origin and lateral line 6-7 (6*, mean = 6.5, n = 19); scale rows between lateral line and pelvicfin origin 4-5 (5*, mean = 4.7, n = 19). Predorsal scales 13-15, arranged in regular series (13*, mean = 13.3, n = 19). Scale rows around caudal peduncle 14-16 (14*, mean = 15.5, n = 19). Triangular modified scale on pelvic-fin origin posteriorly covering three scales. Scale sheath along anal-fin base with 17- 22 (18*) scales in single series, extending to base of 18 th to 20 th branched rays. Precaudal vertebrae 16-17; caudal vertebrae 21-22; total vertebrae 38-39. Supraneurals 5-6 (n = 3). Gill-rakers on upper limb of outer gill arch 7-9, and on lower limb 12-14 (n = 8). Color in alcohol. General body color yellowish to yellowishbrown. Dorsal and dorsolateral portions of head and body pigmented dark brown. Dorsolateral portion of body with scales bordered by dark pigment and forming reticulate pattern. One black humeral spot vertically elongate, wide in dorsal portion and narrowing ventrally; wide dorsal portion of humeral spot located over two or three scales of two scale series just above lateral line; narrow portion crossing lateral line at fourth and/or fifth scales and extending one or two scale series just below lateral line. Midlateral body silvery. Lower half portion of caudal peduncle from region above last anal-fin rays to caudal-fin base black pigmented, usually from the scale row bearing the lateral line to the scales near analfin base and ventral margin of caudal peduncle. Wide and asymmetric black spot covering base of middle caudal-fin rays and extending along entire length of caudal-fin rays 9 to 12-13. Dorsal and caudal fin with dark pigmentation diffuse. Anal fin with small black chromatophores along its border forming narrow stripe. Other fins without distinctive marks (Figs. 1-2). Color just after fixation. Color pattern similar to described for alcohol preserved specimens. Specimens examined soon after fixation in formalin with dorsal and adipose fins and caudal peduncle reddish pigmented, and red spot on ventral portion of caudal-fin base. Sexual dimorphism. Males of Hemibrycon divisorensis are easily recognized by the presence of small bony hooks on the dorsal-, anal-, pelvic-, and pectoral-fin rays (see Description). Also, males and females differ in pectoral and pelvic-fin lengths (Table 1), and anal-fin shape, which is nearly straight in males and concave in females (Figs. 1-2). Mature males do not present gill gland on first arch. Distribution. Hemibrycon divisorensis is known only from the r��o Tapiche drainage, a tributary to the r��o Ucayali, Loreto, Peru. This locality is included in the conservation area ���Zona Reservada Sierra del Divisor��� recently established by the Peruvian government. Etymology. The species name, divisorensis, is in reference to the type locality. A noun in apposition. Ecological notes. The tributaries of r��o Tapiche where the type specimens were collected are about 2-3 m wide with crystalline water, 0.3-0.5 m deep, medium water current, sandy substrate, and with moderate amount of riparian vegetation. Spermatozoa. Hemibrycon divisorensis has a typical aquasperm with a spherical to slightly ovoid nucleus (MCP 28040, 62.7 mm SL), suggesting that the species is non-inseminating (Burns et al., 1995, 1998; Burns & Weitzman, 2005). Due to the lack of mature females, it was not possible to verify the presence of spermatozoa in the ovaries of H. divisorensis., Published as part of Bertaco, Vinicius A., Malabarba, Luiz R., Hidalgo, Max & Ortega, Hern��n, 2007, A new species of Hemibrycon (Teleostei: Characiformes: Characidae) from the r��o Ucayali drainage, Sierra del Divisor, Peru, pp. 251-257 in Neotropical Ichthyology 5 (3) on pages 252-255, DOI: 10.1590/S1679-62252007000300003, http://zenodo.org/record/4567099, {"references":["Burns, J. R., S. H. Weitzman, H. J. Grier & N. A. Menezes. 1995. Internal fertilization, testis and sperm morphology in glandulocaudine fishes (Teleostei: Characidae: Glandulocaudinae). Journal of Morphology, 224: 131 - 145.","Burns, J. R., S. H. Weitzman, K. R. Lange & L. R. Malabarba. 1998. Sperm ultrastructure in Characid fishes (Teleostei: Ostariophysi). Pp. 235 - 244. In.: Malabarba, L. R., R. E. Reis, R. P. Vari, Z. M. S. Lucena & C. A. S. Lucena (Eds.). Phylogeny and Classification of Neotropical Fishes. Porto Alegre, Edipucrs, 603 p.","Burns, J. R. & Weitzman, S. H. 2005. Insemination in Ostariophysan fishes. Pp. 107 - 134. In: Grier, H. J. & M. C. Uribe (Eds.). Viviparous Fishes. New Life Publications, Homestead Florida."]}

Uma nova espécie de caracídeo, Hemibrycon divisorensis, é descrita para a bacia do río Ucayali, Loreto, Peru. A nova espécie distingue-se das demais espécies de Hemibrycon pela presença de uma ampla mancha preta assimétrica na base dos raios da nadadeira caudal estendida até a extremidade dos raios 9 a 12 ou 13 (exceto de H. surinamensis), e de uma faixa preta na metade inferior do pedúnculo caudal desde a região acima dos últimos raios da nadadeira anal até a base da nadadeira caudal. Ela distingue-se da maioria das espécies do gênero pelo número de escamas abaixo da linha lateral (4-5 vs 5-9), exceto de H. jabonero, H. microformaa, H. orcesi e H. surinamensis. Ela difere destas espécies pela contagem de escamas, raios das nadadeiras e colorido padrão. Discute-se e confirma-se a ausência do osso supraorbital em Hemibrycon. A new characid species, Hemibrycon divisorensis, is described from the río Ucayali drainage, Loreto, Peru. The new species is distinguished from all Hemibrycon species by the presence of a wide black asymmetrical spot covering base of caudal-fin rays and extending along entire length of caudal-fin rays 9 to 12-13 (except from H. surinamensis), and a black band in the lower half of the caudal peduncle extending from the region above the last anal-fin rays to the caudal-fin base. Furthermore, it is distinguished from most species of the genus by the number of scale rows below the lateral line (4-5 vs 5-9), except H. jabonero, H. microformaa, H. orcesi, and H. surinamensis. It differs from these species by scale and fin ray counts and color pattern. The lack of a supraorbital in Hemibrycon species is discussed and confirmed.

Andes-to-Amazon river connectivity controls numerous natural and human systems in the greater Amazon. However, it is being rapidly altered by a wave of new hydropower development, the impacts of which have been previously underestimated. We document 142 dams existing or under construction and 160 proposed dams for rivers draining the Andean headwaters of the Amazon. Existing dams have fragmented the tributary networks of six of eight major Andean Amazon river basins. Proposed dams could result in significant losses in river connectivity in river mainstems of five of eight major systems—the Napo, Marañón, Ucayali, Beni, and Mamoré. With a newly reported 671 freshwater fish species inhabiting the Andean headwaters of the Amazon (>500 m), dams threaten previously unrecognized biodiversity, particularly among endemic and migratory species. Because Andean rivers contribute most of the sediment in the mainstem Amazon, losses in river connectivity translate to drastic alteration of river channel and floodplain geomorphology and associated ecosystem services.