Brachyhypopomus beebei ( Schultz, 1944 )

Crampton, William G. R., Santana, Carlos D. de, Waddell, Joseph C. & Lovejoy, Nathan R., 2016, A taxonomic revision of the Neotropical electric fish genus Brachyhypopomus (Ostariophysi: Gymnotiformes: Hypopomidae), with descriptions of 15 new species, Neotropical Ichthyology (e 150146) 14 (4), pp. 639-790 : 669-674

Brachyhypopomus beebei ( Schultz, 1944)

( Figs. 1b , 9 ; Tables 2-5, 7)

Hypopomus beebei Schultz, 1944: 40 , fig. 1, cephalic sensory pore arrangement; 46, pl. 1, fig. 4, black and white photograph of holotype (original description, type locality – Venezuela, Caripito, Monagas, río San Juan, Orinoco dr.). - Schultz, 1949: 66, key to the Hypopomidae , descriptive notes; fig. 9b, cephalic sensory pore arrangement; pl. 2, black and white photograph of holotype ( Venezuela, listing of freshwater fish species). - Hoedeman, 1962: 60, fig. 6b, cephalic sensory pores and canals; fig. 7b, pigmentation ( Suriname, listing of new gymnotiform records). -Hopkins & Heiligenberg, 1978: 132, fig. 10, black and white photograph and EOD ( Suriname, species and EOD diversity). -Westby & Shepherd, 1986: 6, fig. 2; Westby, 1988: 347, fig. 8, black and white photographs of adult male, female and larval specimen, with EODs (French Guiana, species and EOD diversity]. - Hopkins, 1991: 155, fig. 2, black and white photographs of preserved specimens (French Guyana, comparison to Brachyhypopomus pinnicaudatus ). -Ferraris & Vari, 1992: 5 (type catalog). Brachyhypopomus beebei . -Mago-Leccia, 1994: 48, 170, fig. 71, black and white photograph of head of holotype (listing of Brachyhypopomus ). - Crampton, 1996a: 77, table 6.1.a, species list; 79, fig. 6.1 inset 17-18, color photographs; 85, fig. 6.2; 88, fig. 6.3; 92-94, figs. 6.4a, 6.5; 191, fig. 11.2; 193, fig. 11.3, EOD data; 110, table 7.5, 113, table 7.7, 115, fig. 7.1, habitats; 136, table 8.2a,b, diet; 151-160, figs. 9.2, 9.3, table 9.1a,b, hypoxia tolerance; 165-169, table 10.1 reproductive biology ( Brazil, central Amazon, ecology and signal diversity). -Planquette et al., 1996: 396, color photograph of live individual (French Guiana, listing of Brachyhypopomus ). -Alves-Gomes, 1997: 523 ( Brazil, Roraima, listing of gymnotiforms). -Sullivan, 1997: 110 (redescription). - Crampton, 1998a: 821, table 4, 834, fig. 9, drawing of adult specimen, with EOD ( Brazil, Amazonas, species and EOD diversity). - Crampton, 1998b: 314, table 2, list of Brachyhypopomus ( Brazil, Amazonas, hypoxia tolerance). - Provenzano et al., 1998: 11 (type catalog for MBUCV-V). - Crampton, 1999: 17 ( Brazil, Amazonas, Mamirauá Reserve, listing of species). -Stoddard, 1999: 255, fig. 4, color photograph of mature female (EOD evolution). – Stoddard et al., 1999: 610, fig. 1, black and white photograph of mature female with EOD (EOD diversity in Brachyhypopomus ). – Ponton & Mérigoux, 2001: 94, fig. 100, drawings of post-larval morphology ( French Guiana, Sinnamary dr. larval ecology). -Albert & Crampton, 2003: 494 ( Bolivia, Brazil, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, and Venezuela, catalog of hypopomids).–Triques & Khamis, 2003: 63 (diagnosis against, and material examined; in description of B. jureiae ). -Crampton & Albert, 2006: 672, fig. 23.8, position in phylogenetic tree; 681, notes on EODs (gymnotiform species and EOD diversity). - Galvis et al., 2006: 362, fig. 211, drawing of head; 528 ( Colombia, Amazonas, catalog of fishes). - Vari et al., 2009: 46 (Guiana Shield, catalog of fishes). -Crampton, 2011: 176, table 10.2, species list; 179, figs. 10.2-10.3, phylogeny, geographical and ecological distributions (gymnotiform biology). - Mol, 2012: 596, color photograph of preserved specimen, reproduction of photograph from Planquette et al., 1996 ( Suriname, catalog of fishes). - Carvalho, 2013: 181-185, figs. 41-43, position in phylogeny (phylogenetic systematics of Rhamphichthyoidea ). -Crampton & Ribeiro, 2013: 236, color photograph ( Brazil, rio Madeira, listing of hypopomids). - Tagliacollo et al., 2016: 28, fig. 5 (position in phylogeny of the Gymnotiformes ). -Crampton et al., 2016: 1-66, table 1, 3-4, figs. 1-7, 8, 14, 16-17, 18-20 (phylogeny, biogeography and ecology of Brachyhypopomus ).

Brachyhypopomus brevirostris . Kirschbaum, 1995: 452, black and white photograph (gymnotiform diversity).

Diagnosis. Brachyhypopomus beebei is diagnosed from

congeners by the following combination of characters:

prominent pale uninterrupted middorsal stripe from occipital

region to base of caudal filament present, vs. absent in all

congeners except B. arrayae , B. belindae , B. gauderio , B.

pinnicaudatus , and B. verdii ; anal-fin rays 214-230, vs. 174-

212 in B. arrayae and B. pinnicaudatus ; precaudal vertebrae

21-23, vs. 24-26 in B. belindae and B. verdii ; longest anal-fin

ray 1.6-3.9% LEA, vs. 3.9-5.4% in B. gauderio . Description. Head and body shape, and pigmentation illustrated in Figs. 1b and 9 . Meristic and morphometric data for examined specimens are presented in Tables 2-5, and 7. Data presented here refer to material from the central Amazon of Brazil unless otherwise stated. Body moderate to broad in depth. Head short to long, and shallow to moderate in depth. Dorsal profile of head straight to slightly convex from occiput to snout, ventral profile of head straight to slightly convex between operculum and snout, snout rounded and bulbous. Eye moderate in size. Upper jaw with moderate sigmoidal angle between premaxillary and maxillary portions in lateral view. No accessory electric organ over operculum. Gill filaments on first gill arch 35-55 (median 50, n = 20). Pectoral fin moderate to broad in width, pectoral-fin rays 15-19 (mode 14). Precaudal vertebrae 21- 23 (mode 22) including 1-3 (mode 2) transitional vertebrae. Anal-fin origin slightly (<0.25 HL distance) anterior or posterior to, or near, tip of pectoral fin. Anal-fin rays 214- 230 (215-230, median 222 in population from central Amazon; 214 in type region). Dorsal rami of recurrent branch of anterior lateral line nerve not visible. Middorsal region of body scaled. Rows of scales above lateral line 5-7 (mode 6). Lateral line continuous. Groove-like epidermal canals found mainly in posterior half of body – as abundant parallel crisscrossing depigmented grooves either side of lateral line, as isolated horizontal depigmented grooves on flank midway from lateral line to dorsal midline, and as long closely-spaced parallel dark-pigmented lines either side of dorsal surface in dorsal portion of flank. Three bilateral horizontal columns of electrocytes at anal-fin terminus in immature specimens, mature females, and mature males. Three bilateral horizontal columns of electrocytes at mid- point between anal-fin terminus and tip of caudal filament in immature specimens and mature females. Three to four columns of electrocytes at mid-point between anal-fin terminus and tip of caudal filament in mature males (three columns only in specimens from low-conductivity systems; four only in specimens from high-conductivity floodplain systems> 90 μScm-1). Caudal filament short to moderate in length.

Coloration. ( Figs. 1b , 9 ). Background light tan or grey to dark brown. Head darker, especially dorsally. Dorsal region with prominent depigmented pale stripe extending along midline from occipital region to deep into caudal filament. Pale middorsal stripe flanked in anterior portion of body with very thin dark horizontally oriented lines from which thin wavy lines extend ventrally across dorsal and ventral portions of flank. Pale middorsal stripe flanked in posterior portion of body with approximately vertically oriented thin dark lines which extend down flank, some of which cross lateral line into ventral flank. Ventral region with thin wavy dark lines extending from anal-fin margin towards dorsal margin of pterygiophores, some of which extend dorsally to join lines descending from dorsal flank. In caudal filament dark markings form vertical patches or stripes. Head with evenly scattered dark chromatophores, darker dorsally. Eye without prominent suborbital patch, or stripe, of chromatophores/subcutaneous pigmentation. Pectoral and anal-fin membranes hyaline. Pectoral and anal-fin rays hyaline with light scattering of brown chromatophores. Anal-fin ray pigmentation darker in posterior half of fin. Juvenile specimens typically exhibit high contrast dark lines on the flank, set against a pale background pigmentation. In large adults background is typically darker and boundaries of dark lines broken, and less distinctive. Color in live individuals similar to preserved specimens, with opercular region usually rosy due to underlying gills.

Size. Moderate adult size, largest specimen examined 256 mm TL, 190 mm LEA (n = 865). Largest male specimen examined 256 mm TL, 190 mm LEA (n = 36). Largest female specimen examined 197 mm TL, 165 mm LEA (n = 62).

Sexual dimorphism. Males attain larger sizes than females. Males in breeding condition exhibit longer and deeper caudal filaments than immature individuals and breeding females ( Figs. 9 c-d), but do not exhibit an elevated number of bilateral horizontal columns or vertical rows of electrocytes (although we noted that mature males in high-conductivity systems have an extra horizontal column of electrocytes at mid caudal filament, Table 5). Breeding males nonetheless exhibit clearly enlarged electrocytes relative to immature specimens and females. Large males often with paddle-like lateral compression at caudal filament tip ( Figs. 9 c-d). No known sexual dimorphism in pigmentation.

Geographic distribution. Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela ( Fig. 10 ). Widespread through cis-Andean northern South America, including large areas of the Amazonas and Orinoco drainages, and coastal drainages of the Guianas and Amapá State, Brazil. In the Amazon basin apparently absent from the rio Madeira above its series of falls beginning at the Cachoeira de Santo Antônio, near Porto Velho, Rondônia, Brazil. As yet unknown from some major tributaries of the Amazon, including the Juruá, Tocantins, and Xingu. Collection records from tributaries in the northern and western portions of the Orinoco drainage are sparse.

Ecological notes. Brachyhypopomus beebei is an ecologically cosmopolitan species, and is locally common in lentic and slow-flowing freshwater environments throughout its range (Alves-Gomes, 1997; Crampton, 1996a; 1998a; Crampton & Albert, 2006; Crampton & Ribeiro, 2013; Hopkins & Heiligenberg, 1978; Mol, 2012; Westby, 1988). It occurs in seasonally inundated whitewater floodplains (in floating rafts of meadows and shallow newly-flooded forests), along the margins of rivers (in emergent and floating vegetation), in ephemeral or perennial swamps (in vegetation or submerged debris), and in terra firme forest and savanna streams (in emergent and submerged vegetation, leaf litter and debris, and in marginal root mats and holes). In the lowland Amazon, Brachyhypopomus beebei occurs in both low-conductivity blackwater forest streams and swamps (ca. 5-30 μScm-1) and in high-conductivity whitewater floodplain systems (ca. 90-250 μScm-1), as well as in waters of intermediate conductivity ( Crampton, 1996a). Brachyhypopomus beebei often occurs in extremely hypoxic swamp and floodplain systems and is able to tolerate protracted periods of hypoxia by undertaking aerial gill respiration and (during periods of anoxia) by reducing activity ( Crampton, 1998b). Breeding occurs during the rising and high water period in populations from central Amazonian floodplain floating macrophytes ( Crampton, 1996a: 165). Westby (1988) reported the presence of larval B. beebei at the beginning of the rainy season in small streams of coastal French Guiana. Westby (1988) also noted that larval B. beebei , estimated to be less than one week from hatching, occurred in “crèches” of 15- 22 specimens. However, he found no evidence for parental care. Stomach contents in populations from the central Amazon comprise aquatic insect larvae, microcrustacea, and other small aquatic invertebrates - with a predominance of Chironomidae larvae ( Crampton, 1996a: 136). Large specimens often consume larger aquatic invertebrates.

Co-occurring congeners: Because of its wide geographical range and occurrence in multiple habitats, B. beebei occurs in geographical sympatry and ecological syntopy with multiple congeners: in the Amazonas drainage and coastal drainages of the Guianas: B. batesi , B. belindae , B. benjamini , B. bennetti , B. brevirostris , B. cunia , B. hamiltoni , B. hendersoni , B. pinnicaudatus , B. regani , B. sullivani , B. verdii , B. walteri ; in the Orinoco drainage: B. bullocki , B. diazi , B. brevirostris , B. provenzanoi , B. regani , and B. sullivani .

Local names. Brazil: sarapó; Colombia: cuchillo/cuchillo amarillo (Amazon and Orinoco), cuchilleja macana (Putumayo); Ecuador: cuchillo, yayo; French Guiana: poisson couteau (French), and multiple creole/Amerindian names ( Planquette et al., 1996); Peru: macana; Suriname: saprapi; Venezuela: cuchillo.

Material examined. 848 specimens. Brazil. Amapá . MNHN 1981-0494 , 1 (of 3), 88 mm, rio Ipa, rio Oiapoque drainage, no coordinates . MPEG 3341 , 2 , 143-170 mm, mun. Ferreira Gomes, rio Cupixi, bridge on hwy. to Serra do Navio, rio Araguari drainage, ca. 00°55′N, 051°15′W . Amazonas (localities from Amazonas dr., localities listed from the Mamirauá Reserve [Reserva de Desenvolvimento Sustentável Mamirauá] are in rio Solimões-Japurá floodplain, mun. Alvarães). BMNH 1998.3.12.45-53, 9 (6 immature, 122-176 mm, 2 female, 150-190 mm, 1 male, 145 mm), IDSM 442, 8, 73-187 mm , MCP 45313 , 1 , immature, Mamirauá Reserve , cano do lago Rato, 03º02′41″S, 064º51′26″W . BMNH 1998.3.12.54, 1, immature, 122 mm, mun. Tefé, floodplain lake, Ilha Panamim, rio Solimões , 03º17′38″S, 064º41′16″W . BMNH 1998.3.12.55, 1, immature, 150 mm, MCP 45381 , 5 (2 immature [1CS], 105-140 mm, 2 female, 162-164 mm, 1 male, 220 mm), Mamirauá Reserve, Ressaca do Caetono , 02º50′15″S, 064º55′50″W . IDSM 452 , 3 , 62-98 mm, Mamirauá Reserve , lago Jaraqui, 02º44′07″S, 065°04′38″W . IDSM 453 , 6 , 52-129 mm , MCP 45424 , 5 (3 immature, 94-132 mm, 1 female, 171 mm, 1 male, 204 mm) , MCP 45428 , 5 , 45-194 mm , MCP 45450 , 5 (2 immature [2CS], 102-195 mm, 3 female [2CS], 138-178 mm), Mamirauá Reserve , lago Secretaria, 03º07′12″S, 064°47′49″W . INPA 9943 , 15 , 85-150 mm, Mamirauá Reserve , lago Mamirauá, ca. 03º07′S, 064º47′W . INPA 18335 , 1 , immature, 114 mm, Mamirauá Reserve , cano do lago Arauaé, 03º03′54″S 64º49′04″W . INPA 18336 , 1 , immature, 53 mm , MCP 45358 , 1 , immature, 109 mm, Mamirauá Reserve , lago Araçazinho, 02º59′35″S, 064º51′33″W . INPA 18337 , 1 , immature, 90 mm , MCP 45361 , 1 , immature, 63 mm , MCP 45385 , 2 , immature, 120-146 mm, Mamirauá Reserve , cano do lago Sapucaia, 03º04′07″S, 064°48′32″W . INPA 18338 , 1 , immature, 114 mm , MCP 45343 , 1 , female, 198 mm , MCP 45380 , 1 , immature, 65 mm, Mamirauá Reserve , cano do lago Mamirauá, 03º06′40″S, 64°47′52″W . INPA 18339 , 1 , immature, 50 mm , MCP 45427 , 3 (2 female [1CS], 136- 153 mm, 1 male, 170 mm), mun. Tefé, igarapé Curupira, Estrada Agrovila rd., affl. lago Tefé, rio Tefé , 03º25′48″S, 064º44′15″W . INPA 18340 , 1 , immature, 59 mm , MCP 45488 , 1 , female, 136 mm, mun. Tefé, terra firme swamp, igarapé Repartimento, Estrada Agrovila rd., affl. lago Tefé, rio Tefé , 03º24′25″S, 064º44′08″W . INPA 18341 , 1 , immature, 75 mm, Mamirauá Reserve , Paraná Maiana, 03º06′50″S, 064°47′48″W . MCP 45342 , 1 , immature, 133 mm , MCP 45344 , 1 , immature, 135 mm, Mamirauá Reserve , lago Arauaé, 03º02′52″S, 064º50′04″W . MCP 45382 , 2 , immature, 118- 139 mm, Mamirauá Reserve, Ressaca do Itu , 02º49′51″S, 064º57′11″W . MCP 45383 , 1 , female, 185 mm, Mamirauá Reserve, Ressaca da Vila Alencar , 03º07′41″S, 064°48′04″W . MCP 45387 , 1 , immature ( CS), 97 mm, Mamirauá Reserve, lago Periquito Comprido , 03º04′57″S, 064°46′42″W . MCP 45420 , 1 , male, 197 mm, Mamirauá Reserve , lago Curuçá Aberto, 03º06′07″S, 064°49′10″W . MCP 45421 , 2 (1 immature, 132 mm, 1 male [CS], 201 mm), Mamirauá Reserve , cano do lago Mamirauá, 03º04′29″S, 064°48′29″W . MCP 45422 , 1 , male, 226 mm, Mamirauá Reserve , cano do lago Mamirauá, 03º05′15″S, 064°48′03″W . MCP 45459 , 3 , 95-118 mm, Mamirauá Reserve, Ressaca do Caetono , 02º50′15″S 64º55′50″W . MCP 45460 , 1 , immature, 72 mm , MCP 45462 , 6 (5 not sexed, 83-151 mm, 1 female, 134 mm), mun. Tefé, igarapé Repartimento, 1.5 km downstream bridge Estrada Agrovila rd., affl. lago Tefé, rio Tefé , 03º24′25″S, 064º44′08″W . MPEG 22741 , 1, 108 mm, Mamirauá Reserve , cano do lago Geraldo, 03º07′20″S, 064°48′06″W . MPEG 22742 , 2 , 90-145 mm, Mamirauá Reserve , lago Bolsinho, 03º03′47″S, 064°49′59″W . MZUSP 7293 , 4 , mun. Maués, igarapé do rio Maraú, affl. rio Maués-Açu , ca. 03º24′S, 057°42′W . MZUSP 23239 , 9 , lago Miuá, upstream Codajás, rio Solimões , ca. 03°40′S, 062°04′W . MZUSP 44164 , 2 , mun. Maués, igarapé Limãozinho, affl. rio Maués-Açu , ca. 03°23′S, 057°43′W [coordinates for Maués]. MZUSP 62069 , 1 , 53 mm, pool on beach, Tapera, rio Negro , ca. 00°11″N, 064°04″W . UF 177346 , 13 , 64-211 mm, Mamirauá Reserve , lago Secretaria, 03º07′12″S, 064°47′49″W . Maranhão. USNM 88283 , 1, 140 mm, “Maranhão, Brazil”, no coordinates. Pará (localities from Amazonas dr.) . INPA 6887 , 1, 131 mm, Pimental, rio Tapajós , ca. 04°34′S, 056°15′W . MCP 23359 (part), 1, 94 mm, Concórdia do Pará, rio Bujarú, affl. rio Guamá , affl. Baía do Guajará , ca. 02°06′S, 047°56′W . MPEG 7140 , 1 , 95 mm, mun. Barcarena, São Sebastião, rio Arienga, affl. Baía do Guajará , 01°38′S, 048°43′W . MPEG 10164 , 1, 115 mm, mun. Portel, Floresta Nacional Caxiuanã, affl. rio Anapú, affl. rio Pará, affl. Baía do Guajará , ca. 01°44′S, 051°26′W . MPEG 15336 , 1 , 99 mm, mun. Faro, unnamed stream, affl. rio Nhamundá , 01°42′23″S, 057°12′10″W . MPEG 15646 , 1, 130 mm, mun. Almeirim, rio Ipitinga, affl. rio Jari , 00°49′52″N, 053°57′20″W . MPEG 15679 , 1, 122 mm, mun. Almeirim, rio Ipitinga, affl. rio Jari , 00°48′34″N, 053°55′52″W . SU 54499 , 6 , 74-106 mm , SU 66948 , 1 , 90 mm, Urumari brook into rio Tapajós, Santarém , ca. 02°26′S, 054°42′W [coordinates for Santarém]. Rondônia (localities from rio Madeira dr., Amazonas dr.). INPA 818 , 2 , 118-127 mm , INPA 1154 , 2 , 121-132 mm, igarapé “13.05”, rio Mutum, Serra Pacaás Novos, affl. rio Mamoré [coordinates for Serra Pacaás Novos], ca. 10º47′S, 063º59′W . INPA 19947 , 4 , 61-153 mm , INPA 19948 , 73 , 34-131 mm, Lagoa do Feijoal, rio Jamari , upstream UHF Samuel, ca. 15 km, ca. 08°51′S, 063°19′W . UFRO-I 4470 , 1, 118 mm, igarapé Lourdes, affl. igarapé Cristal, affl. rio Jí-Paraná , 10°25′13″S, 61°39′12″W . UFRO-I 6481 , 1 , 91 mm, flooded area immediately downstream Cachoeira Santo Antônio, rio Madeira , 08°46′30″S 63°56′28″W . Roraima (localities from rio Branco dr., affl. rio Negro, Amazonas dr.). INPA 6404 , 4 , 43-108 mm, Ilha de Maracá, stream at end of island, rio Uraricoera , ca. 03°22′N, 061°23′W . INPA 7387 , 1 , igarapé Viruaquim [Juruaquim], 48.8 km Normândia on hwy. RR-202, 03°50′N, 60°02′W (listed by Sullivan, 1997) . MZUSP 23567 , 1 , stream ca. 1 km N Caracaraí , 01°52′N, 061°06′W . MZUSP 30037 , 48 , MZUSP 30039 , 58 , igarapé do Cujobim, Ilha de Maracá, rio Uraricoera , ca. 03°20′N, 061°40′W . MZUSP 30038 , 10 , igarapé do Bota Panela, nr. Cachoeira do Bem Querer, rio Branco , ca. 01°55′N, 061°00′W . Colombia. Amazonas. ROM 56332 , 1, 207 mm, 5 mi. W Leticia, Amazonas dr., 04°09′02″S, 069°57′00″W . Caquetá. SINCHI-CIACOL 102, 2, 42-129 mm, Comunidad Aduche (San Miguel), Pueblo Andoke, Poblado Araracuara, affl. río Caquetá , Amazonas dr., 00°38′18″S, 072°10′54″W . Ecuador (localities from río Napo dr., Amazonas dr.) Francisco de Orellana. FMNH 102272 , 1 , 60 mm, Laguna Jatuncocha, río Yasuni , 01°00′S, 075°27′W . QCAZ-I 1369 , 1, 123 mm, Chiruisla, río Huiririma, affl. río Tiputini , 00°38′54″S, 075°54′44″W . QCAZ-I 1802 , 1, 147 mm, QCAZ-I 1803, 1, 162 mm, Chiruisla, Laguna Muyuna, affl. río Tiputini , 00°42′25″S, 075°56′08″W . Sucumbios. ANSP 130488 , 5 , 37-103 mm, swamp at Santa Cecília, río Aguarico , ca. 00°06′N, 076°51′W . FMNH 102271 , 1 , 76 mm, Laguna de Limoncocha , 00°23′42″S, 076°36′49″W . FMNH 102279 , 1, 154 mm, small stream between Laguna Zancudo and Laguna Zancudococha, affl. quebrada Zancudococha, affl. río Aguarico , 00°33′42″S, 075°30′00″W . FMNH 102281 , 6 , 34-103 mm, ca. 2 km S Marian, río Aguas Negras, about 1-2 km upstream from rd. bridge, affl. río Cuyabeno, affl. río Aguarico , ca. 00°01′S, 076°19′W . FMNH 102284 , 6 , 20- 93 mm, affl. Laguna Grande de Cuyabeno, affl. río Cuyabeno, affl. río Aguarico , ca. 00°00′S, 076°10′W . FMNH 102290 , 1 , 51 mm, affl. río Tarapuy, N bank just downstream rd. bridge, affl. río Cuyabeno, affl. río Aguarico, no coordinates. KU 12741, 1 ( CS), 90 mm; KU 13799, 4, 38-120 mm; KU 13800, 24 (4 CS), 50-145 mm, swamp, S air strip at Santa Cecília , río Aguarico , ca. 03°52′S, 076°59′W . MUSM 5693 (part), 2, 107-117 mm, temporary lake, río Aguarico , ca. 00°38′S, 075°21′W [coordinates for mouth of río Aguarico]. French Guiana. Cayenne. BMNH 1926.3.2.658-660, 3, 78-85 mm, crique Iponcin, Approuage River dr., no coordinates. CU 71944, 2, on Rt. 1 Kourou to Sinnamary, km 86 in flooded border of crique Paracou , Kourou River dr., ca. 05°21′N, 052°56′W (listed by Sullivan, 1997) . CU 71954, 1, Kourou River at Roche Leodate landing, ca. 32 km upstream from Kourou, Kourou River dr., 05°00′N, 052°39′W (listed by Sullivan, 1997) . CU 71955, 1, crique Papinabo, ca. 21 mi. from Kourou, Kourou River dr., 05°06′N, 052°40′W (listed by Sullivan, 1997) . CU 71956, 5, small coastal stream on “CTFT forestry estate” nr. crique Paracou, Kourou River dr., ca. 05°21′N, 052°56′W (listed by Sullivan, 1997) . MNHN 1981-0495 , 1, 78 mm, Trois Sauts (falls) on Oyapock River, rio Oiapoque dr., ca. 02°15′N, 052°51′W . MNHN 1981-0566 , 1, 95 mm, saut Embouchure, Yaroupi River, affl. Oyapock River, rio Oiapoque dr., ca. 02°42′N, 053°01′W . MNHN 1999-1314 , 10 (of 39), 28-49 mm, crique Papinabo, Kourou River dr., ca. 05°06′N, 052°41′W . MNHN 1999-1321 , 1 (of 3), 120 mm, Oyapock River, rio Oiapoque dr., no coordinates . MNHN 1999- 1364 , 1 (part), 153 mm, Pont de Papinabo, crique de Papinabo, River Kourou dr., ca. 05°06′N, 052°41′W . NRM 29482 , 1 , 60 mm, locality marked “PK12”, corresponds to following record from MNHN databases: Pont de Papinabo, crique de Papinabo, Kourou River dr., ca. 05°06′N, 052°41′W . NRM 32241 , 2 , 55-59 mm, flooded area along rd. Sinnamary-Saint-Laurent, Sinnamary River dr., ca. 05°25′20″N, 053°03′28″W . NRM 32242 , 1 , 51 mm, Oyapock River nr. St. Georges - Maripa Rd crossing, rio Oiapoque dr., ca. 03°52′13″N, 051°51′17″W . NRM 32243 , 1 , 50 mm, crique Soumouro, Kourou River dr., 05°07′27″N, 052°43′52″W . USNM 301964 , 2 , 165-176 mm. crique Karouabou, nr. Kourou city, Kourou River dr., ca. 05°09′N , 052°40″W. USNM 301965 , 1, 138 mm. crique Papinabo, 200 m upstream from Kourou River, 20 km Kourou, Kourou river dr., ca. 05°00′N, 052°42″W . Guyana. Barima-Waini. BMNH 1911.10.31.556, 1, 143 mm, FMNH 53322, 1, 110 mm, Issorora rubber plantation, Mud Creek [probably on Aruka River], Aruka River dr., Barima-Kaituma River dr., 08°12′N, 059°44′W [coordinates for lower Aruka ] . Cuyuni-Mazaruni. BMNH 1934.9.12.360, 1, 106 mm, Mazaruni River, pond in forest near small community, Essequibo River dr., no precise locality [coordinates for confl. with Essequibo River] 06°20′N, 058°41′W . Demerara [old division name]. FMNH 85374 , 2 , 101-110 mm, Dakara Creek , no coordinates . Potaro-Siparuni (localities from Essequibo River dr.). ANSP 175956 , 4 , 67-163 mm, Culvert creek crossing Kurupukari-Surama River rd. , 04°19′57″N, 058°51′13″W . ANSP 175957 , 1, 158 mm, blackwater creek, 5 min. upstream from Burro Burro campsite, Iwokroma, ca. 04°40′N, 058°50′W . ANSP 175958 , 6 , 52-75 mm, small lake, 04°45′15″N, 058°45′12″W . ANSP 192059 , 2 , 67-74 mm, creek, Tumble Down Falls, Tumble Down Creek, Siparuni River , 04°48′59″N, 058°50′56″W . BMNH 1973.3.29.14-15, 2, 96-101 mm, Kaieteur falls, 2 mi. above ‘gauge’, Potaro River , 05°09′N, 059°28′W . CAS 72220 , 1 , 59 mm, CAS 72226, 1, 54 mm, Chipoo Creek, affl. Ireng River , ca. 04°42′N, 059°06′W . FMNH 53325 , 1, 121 mm, MCZ 30175, 1, 153 mm, Nickaparoo (or Nickaparu) Creek, affl. River Ireng, above the Karona falls , ca. 04°42′N, 059°06′W . INHS 49616 , 1, 120 mm, 2.9 mi. E Chenapou, Arnick Creek, affl. Potaro River , 04°59′56″N, 059°32′20″W . SU 72222 , 2 , 113-119 mm, Nickaparoo Creek, into Ireng River , ca. 04°42′N, 059°06′W . Upper Takutu-Upper Essequibo (Localities listed for Takutu River are from the rio Branco dr., affl. rio Negro , Amazonas dr.). AUM 35866 , 1 , 43 mm, 31.2 km NW Sand Creek village, Sauriwau River , affl. Takutu River , 03°06′51″N, 059°46′31″W . BMNH 1972.7.27.458-518 (part), 2, 95-102 mm, Karanambo creek, Rupununi River, Essequibo River dr., 03°45′11″N, 059°18′36″W . FMNH 53327 , 1, 112 mm, Twoca Pan, between Rupununi and Pununike, Essequibo River dr., no coordinates . MCZ 165853 , 1, 102 mm, Dry creek bed 10 mi. E Nappi village, [probably Moco-Moco River], affl. Takutu River , ca. 03°25′N, 059°25′W . USNM 209199 , 3 , 101-127 mm, Rupununi, Moco-Moco Creek, affl. Takutu River , ca. 03°15′N, 059°39′W . Region not specified. AMNH 3247 , 1 , 65 mm, Guyana, no further locality data, drainage unknown, no coordinates, FMNH 53324, 1, 95 mm, Pacopoo Pan, drainage unknown, no coordinates . USNM 377591 , 2 , 115-128 mm, Hassar Creek , no coordinates . Peru (localities are from Amazonas dr.). Amazonas. LACM 41763-2 , 1, 110 mm, 1 km upstream from Caterpiza, río Santiago, affl. río Marañón , Amazonas dr., ca. 03°54′S, 077°42′W . Loreto (localities listed from nr. Jenaro Herrera are from the río Ucayali dr., mun. Requena ). ANSP 167725 , 4 , 55-78 mm, río Nanay , ca. 6 mi. upstream confl. with río Momón , ca. 03°44′50″S, 073°17′12″W . ANSP 167726 , 2 , 76-90 mm, nr. Mishana on path to Nauta rd., affl. río Nanay , 03°53′12″S, 073°28′57″W . ANSP 167727 , 11 , 60-85 mm, Laguna Rocafuerte, río Nanay, ca. 6.1 mi. upstream confl. with río Momón ca. 03°44′S, 073°17′W . ANSP 178219 , 1 , 53 mm, caño Santa Rita, R. bank affl. río Nanay , nr. Pueblo Pampa Chica, 03°45′23″S, 073°17′28″W . CAS 67701 , 4 , 87-128 mm, creek nr. Yurimaguas, affl. río Huallaga, affl. río Marañón , ca. 05°53′S, 076°04′W . CAS 67702 , 4 , 37-213 mm, stream, affl. río Itaya, affl. río Amazonas , ca. 03°48′S, 073°16′W . INHS 50010 , 2 , 102-108 mm, caño Ushpa, 4 km E Iquitos, affl. río Itaya, affl. río Amazonas , ca. 03°48′S, 073°16′W . MNRJ 3957 , 1, 197 mm, rio Ampiyacu, nr. Pebas, affl. río Amazonas , ca. 03°19′S, 071°51′W . MUSM 6959 (part), 1, 72 mm, Isla Muyuy, cocha Amazonas, río Amazonas , ca. 03°54′S, 073°14′W . MUSM 10914 , 1 , mun. Urarinas, río Chambiras nr. San Juan, río Nanay , ca. 03°41′S, 073°45′W . MUSM 11009 , 1 , Pijuayal, río Hormiga, affl. rio Amazonas , 04°08′S, 070°03′W . MUSM 14498 (part), 1, 73 mm, mun. Maynas, Puesto de Vigilancia Arcadia, río Napo , 00°59′37″S, 075°18′30″W . MUSM 44675 , 22 (14 immature, 48-163 mm, 5 female, 157-190 mm, 4 male, 148-222 mm), stream nr. Jenaro Herrera, 04°53′59″S, 073°38′51″W . MUSM 44681 , 4 , immature, 50-133 mm, stream nr. Jenaro Herrera, 04°53′35″S, 073°39′01″W . MUSM 44693 , 8 (1 immature, 157 mm, 3 female, 148-185 mm, 4 male, 164-210 mm), stream nr. Jenaro Herrera, 04°51′51″S, 073°38′45″W . MUSM 44703 , 14 (13 immature, 84-188 mm, 1 female, 169 mm), stream nr. cocha Capite, nr. Jenaro Herrera, 04°52′03″S, 073°40′39″W . MUSM 44712 , 2 , immature, 8133 mm, stream nr. Jenaro Herrera, 04°53′54″S, 073°38′23″W . MUSM 44718 , 4 (3 immature 87-196 mm, 1 male, 155 mm), stream nr. Jenaro Herrera, 04°56′16″S, 073°39′20″W . MUSM 44721 , 14 (8 immature, 5922 mm, 3 female, 14784 mm, 2 male, 154-192 mm), stream nr. Jenaro Herrera, 04°55′41″S, 073°38′46″W . MUSM 44762 , 18 , immature, 58-90 mm, stream nr. Jenaro Herrera, 04°54′36″S, 073°39′58″W . MUSM 44768 , 7 (1 immature, 106 mm, 3 female, 91-155 mm, 3 male, 125-139 mm), cocha Capite, nr. Jenaro Herrera, 04°54′15″S, 073°36′53″W . NRM 27763 , 1, 143 mm, stream nr. Jenaro Herrera, ca. 04°54′23″S, 073°37′27″W . SU 17230 , 1, 204 mm, río Amazonas nr. Pebas, ca. 03°19′S, 071°37′W . UF 116551 , 1 , immature, 80 mm, río Nanay at Mishana, 03°52′48″S, 073°29′30″W . UF 116555 , 1 , immature, 86 mm, stream at km 23, Iquitos-Nauta rd., affl. río Nanay , 03°56′38″S, 073°23′54″W . UF 126211 , 1, 112 mm , UF 131121 , 1 , 67 mm, Reserva Nacional ( RN) Pacaya Samiria, río Pacaya, affl. río Ucayali , ca. 05°16′S, 074°27′W . UF 126237 , 1, 127 mm , UF 126247 , 3 , immature, 11831 mm , UF 148564 , 5 (2 immature, 68-76 mm, 3 female, 7416 mm), RN Pacaya Samiria, cocha Sapote, río Pacaya, affl. río Ucayali , 05°19′06″S, 074°29′18″W . UF 129052 , 1 , 76 mm, RN Pacaya Samiria, río Pacaya, affl. río Ucayali , ca. 05°25′18″S, 074°30′45″W . UF 129117 , 1 , 77 mm, RN Pacaya Samiria, río Pacaya, affl. río Ucayali , ca. 05°18′14″S, 074°30′45″W . UF 129157 , 1, 110 mm, RN Pacaya Samiria, río Pacaya, affl. río Ucayali , ca. 05°23′57″S, 074°32′06″W . UF 129161 , 3 , 72-100 mm, RN Pacaya Samiria, río Pacaya, affl. río Ucayali , ca. 05°23′51″S, 074°30′23″W . UF 129406 , 3 , 52-102 mm, RN Pacaya Samiria, río Pacaya,affl. río Ucayali , ca. 05°19′20″S, 074°30′14″W . UF 148505 , 4 (1 male, 130 mm, 3 female, 122-143 mm), stream nr. Jenaro Herrera, 04º55′38″S, 073º39′14″W . UF 148506 , 2 , immature, 34-42 mm, quebrada Salomé caño, stream nr. Jenaro Herrera, 04º54′32″S, 073º35′36″W . UF 148507 , 1 , immature, 66 mm, affl. quebrada Parnayari, nr. Jenaro Herrera, ca. 04º54′S, 073º37′W . UF 148508 , 2 (1 immature 68 mm, 1 female, 164 mm), quebrada Parnayari, nr. Jenaro Herrera, 04º55′10″S, 073º38′40″W . UF 148509 , 1 , immature, 51 mm, stream, affl. quebrada Chica, nr. Jenaro Herrera, 04º55′23″S, 073º39′37″W . UF 148510 , 3 (2 female, 170-197 mm, 1 male, 217 mm), quebrada Fierro caño, affl. quebrada Sapuenillo, nr. Jenaro Herrera, 04º51′39″S, 073º38′59″W . UF 148556 , 1 , immature, 88 mm, RN Pacaya Samiria, caño Yarina, río Pacaya, affl. río Ucayali , 05°20′08″S, 074°30′05″W . UF 148557 , 1 , immature, 7 mm, RN Pacaya Samiria, caño Yarina, río Pacaya, affl. río Ucayali , 05°19′20″S, 074°30′11″W . UF 148558 , 3 (1 immature, 70 mm, 2 female, 102-129 mm), RN Pacaya Samiria, cañoYarina, río Pacaya, affl. río Ucayali , 05°18′16′S, 074°30′05″W . UF 148559 , 17 (4 immature, 80-106 mm, 11 female, 90-136 mm, 2 male, 107-125 mm), RN Pacaya Samiria, cocha Yarina, río Pacaya, affl. río Ucayali , 05°23′51″S, 074°30′23″W . UF 148560 , 3 , (1 immature, 44 mm, 2 female, 126-135 mm), RN Pacaya Samiria, cocha Yarina, río Pacaya, affl. río Ucayali , 05°25′20″S, 074°30′45″W . UF 148561 , 5 (4 immature, 104-149 mm, 2 female, 125-161 mm), RN Pacaya Samiria, cocha Yarina, río Pacaya, affl. río Ucayali , 05°23′58″S, 074°32′05″W . UF 148562 , 4 (2 immature, 87-122 mm, 2 female, 160 mm), RN Pacaya Samiria, cocha Yarina, río Pacaya, affl. río Ucayali , 05°25′29″S, 074°31′41″W . UF 148563 , 1 , female, 133 mm, RN Pacaya Samiria, caño Tamara, río Pacaya, affl. río Ucayali , 05°16′40″S, 074°29′38″W . UF 148565 , 3 (1 immature 73 mm, 2 female, 143-177 mm), RN Pacaya Samiria, río Pacaya, río Ucayali, affl. río Ucayali , 05°16′44″S, 074°31′06″W . UF 148566 , 5 (4 immature, 64-72 mm, 1 female, 109 mm), RN Pacaya Samiria, cocha Shitari, affl. río Ucayali , ca. 05°17′S, 074°31′W . UF 183770 , 1, 256 mm, río Nanay , 03°53′50″S, 073°40′01″W . UF 184013 , 9 (6 immature, 56-199 mm, 2 female, 159-183 mm, 1 male, 96 mm), stream nr. Jenaro Herrera, 04°52′24″S, 073°38′49″W . UF 184022 , 33 (16 immature, 56-158 mm, 8 female, 120-170 mm, 9 male, 148-198 mm), stream nr. Jenaro Herrera, 04°55′38″S, 073°39′14″W . UF 184023 , 3 (2 immature, 64-139 mm, 1 female, 164 mm), stream nr. Jenaro Herrera, 04°54′15″S, 073°36′53″W . UMMZ 224598 , 3 , 62-156 mm, río Cayarí, nr. Benjamin Constant, affl. río Yavarí ( rio Javari ), ca. 04°22′S, 070°01′W [coordinates for Benjamin Constant]. UMMZ 224603 , 2 , 106-153 mm, río Tapira, río Tahwayo [Tahuayo], ca. 04°17′S, 073°12′W . UMMZ 224604 , 1, 111 mm, río Momón, nr. Iquitos, affl. río Nanay , 03°37′55″S, 073°19′47″W . UMMZ 228983 , 2 , 131-135 mm, quebrada Carana, Buensuceso, rio Javari , 04°07′S, 070°25′W . UMMZ 228984 , 13 , 33-119 mm, río Momón, affl. río Nanay , ca. 03°37′S, 073°17′W . Ucayali. FMNH 84226 , 1 , 60 mm, first bridge over stream, ca. 34 km Pucallpa, on Pucallpa-Lima hwy., affl. río Ucayali , 08°34′17″S, 074°54′17″W . MUSM 39375 , 5 , 56-61 mm, pools in caño draining Supari cocha, nr. San Miguel village, río Purus , 09°58′12″S, 070°56′09″W . Suriname. Marowijne. UF 177358 , 1 , male, 161 mm, small unnamed stream on Paramaribo-Albina rd., affl. Cottica River, Commewijne River dr., 05°34′55″N, 054°15′49″W . ZMA 102.377, 1, 83 mm, Albina, Marowijne River dr., ca. 05°29′58″N, 054°03′44″W . Nickerie. USNM 22588 , 21 , 32-97 mm, Lana Creek, ca. 4 km upstream confl. with Corantijn River, Corantijn River dr., ca. 05°27′N, 057°15′W . USNM 225557 , 1 , 57 mm, creek at Camp MacClemmen, Dalibane Creek, Corantijn River drainage, 05°34′N, 057°11′W . USNM 225559 , 5 , 45-132 mm, Kapoeri Creek, ca. 4 km N confl. with Corantijn River, Corantijn River dr., 05°16′N, 057°10′W . USNM 225562 , 4 , 57-70 mm, creek ca. 2 km N Matapi, Corantijn River dr., 05°03′N, 057°17′W . USNM 225568 , 2 , 70-114 mm, small creek affl. Corantijn River, 350 m below Wilhelm II falls, Corantijn River dr., 03°34′N, 057°39′W . USNM 225572 , 1, 100 mm, Makilikabroe Creek , Corantijn rivier dr., 05°26′N, 057°14′W . Paramaribo. ZMH 11630 , 1, 127 mm, Paramaribo, Suriname River dr., ca. 05°53′N, 055°10′W . Sipaliwini. AMNH 54831 , 1 , 67 mm, stream nr. Avanavero Falls, ca. 3 mi. downstream Devis Falls, Corantijn River dr., ca. 04°49′N, 057°24′W . AMNH 244582 , 2 , 68-70 mm, small stream S Tiger Falls, km 405, Corantijn River dr., ca. 03°56′N, 057°56′W . FMNH 116894 , 1, 112 mm, unnamed creek on Linker Coppename, Coppename River dr., 04°23′25″N, 056°31′52″W . USNM 225564 (part), 7, 75-125 mm, small stream 200 m upriver Dalbana Creek mouth, Corantijn River dr., ca. 04°47′N, 057°26′W . USNM 302003 , 1, 143 mm, Matapi Creek ca. 1 km confl. with Corantijn rivier, Corantijn River dr., ca. 05°00′N, 057°16′W . ZMA 107.029, 5, 130-182 mm, stream into left bank Gran rio, 3 km NE Awaradam, affl. Gran rio, Suriname River dr., ca. 03°51′N, 055°25′W . ZMH 11629 , 1, 143 mm, “ upper Suriname ”, no coordinates . Venezuela. Amazonas. MBUCV-V 13895 , 6 (3 measured: 136-167 mm), caño Niyayowa, W Parima, affl. rio Negro , Amazonas dr., ca. 03°30′N, 064°15′W . MBUCV-V 14766 , 1, 141 mm, small stream, 1 km S La Neblina camp, affl. río Baria, aff. río Casiquiare, affl. rio Negro , Amazonas dr., ca. 00°50′N, 066°05′W . MCNG 23657 , 3 , Mauritia palm swamp, 1 km N Esmeralda, río Orinoco, Orinoco dr., 03°11′N, 065°33′W . MCNG 23894 , 1 , forest pools, río Ventuari , Orinoco dr., ca. 03°59′N, 067°02′W [coordinates for mouth of río Ventuari]. MCNG 23903 , 1 , morichal, río Guapuche, affl. río Ventuari, río Orinoco drainage, ca. 04°06′N, 066°46′W [coordinates for mouth of río Guapuche]. MHNLS 5873 , 1 , MHNLS 6437 , 1 , Malvaca, alto río Orinoco , Orinoco dr., 02°30′N, 065°09′W . UMMZ 228986 , 2 , pool of creek nr. Puerto Ayacucho, affl. río Orinoco , Orinoco dr., ca. 05°38′N, 067°36′W . Apure. MBUCV-V 10776 , 1, 101 mm, caño Grande, 3 km S La Ceiba, affl. río Apure , Orinoco dr., ca. 07°19′N, 071°08′W . Barinas. MBUCV-V 5960 , 2 , 69-70 mm, caño San Antonio, ca. 10 km Santa Barbara de Barinas, río Anaro, affl. río Suripá, affl. río Apure , Orinoco dr., ca. 07°48′N, 071°10′W . Monagas. AMNH 15453 , 2 (paratypes), 95-146 mm , MBUCV-V 15163 , 1 (paratype), 130 mm , USNM 120753 , 1 (holotype) ( Fig. 9b , herein), 103 mm (originally 136 mm TL, 112 mm LEA ( Schultz, 1944), caudal filament now lost), Caripito, río San Juan, Orinoco dr., ca. 10°06′N, 063°06′W , C. Beebe, 1942. MBUCV-V 22343 , 1 , 94 mm, río Morichal Largo, río Orinoco delta, Orinoco dr., 09°26′N, 062°24′W . Country not specified. USNM 302011 , 2 , 101-130 mm, no locality, no coordinates .

Figures

Fig. 1. Live individuals of 12 sympatric species of Brachyhypopomus and one species of Microsternarchus from the vicinity of Tefé, Amazonas, Brazil (Amazonas dr.). a. Brachyhypopomus batesi MCP 45312 (WC01.191293b), immature, 102 mm TL. b. Brachyhypopomus beebei head – uncat., immature, 75 mm TL; body – MCP 45450 (WC04.090600), female, 178 mm TL. c. Brachyhypopomus belindae MCP 45430, paratype, immature, 104 mm TL (photographed out of water, close up of head not available). d. Brachyhypopomus bennetti MCP 45451, male, 196 mm TL. e. Brachyhypopomus brevirostris uncat., immature, 224 mm TL. f. Brachyhypopomus flavipomus MCP 45453 (WC09.090600), female, 98 mm TL. g. Brachyhypopomus hamiltoni MCP 45482 (WC05.080301), holotype, female, 97 mm TL. h. Brachyhypopomus hendersoni MCP 45489, female, 164 mm TL. i. Brachyhypopomus pinnicaudatus MCP 45455, female, 135 mm TL. j. Brachyhypopomus regani, MCP 45285 (WC02.100301), male, 119 mm TL. k. Brachyhypopomus sullivani MCP 45464 (WC04.210201), immature, 79 mm TL. l. Brachyhypopomus walteri MCP 45458 (WC 03.090600), male, 161 mm TL. m. Microsternarchus bilineatus uncat., 85 mm TL.

Fig. 9. Brachyhypopomus beebei. a. MCP 45462 (WC04.150801b), immature female, 134 mm TL, non-type (head in lateral view, body in lateral and dorsal view, specimen fixed in formalin); Brazil, rio Tefé, Amazonas dr. b. USNM 120753, holotype, 103 mm TL (originally 136 mm TL, tail now lost) (body in lateral view, specimen preserved in EtOH); Venezuela, río San Juan, Orinoco dr. c. MCP 45424 (WC04.010599), male, 204 mm TL, non-type (body in lateral view, specimen fixed in formalin and preserved in EtOH); d. MCP 45427 (WC01.130300), female, 153 mm TL, non-type (body in lateral view, specimen fixed in formalin and preserved in EtOH); Brazil, rio Solimões-Japurá confluence, Amazonas dr. Note the sexual dimorphism in caudal filament height. Scale bars = 5 mm.

Fig. 10. Collection records for Brachyhypopomus beebei (circles). Holotype location is marked with an open symbol. Elevation data refers to altitude above mean sea level (see Fig. 2 for legend).