Brachyhypopomus pinnicaudatus (Hopkins, Comfort, Bastian & Bass, 1990)

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 : 753-757

Brachyhypopomus pinnicaudatus (Hopkins, Comfort, Bastian & Bass, 1990)

( Figs. 1i , 38 ; Tables 2-5, 18)

Hypopomus pinnicaudatus Hopkins et al., 1990: 352 , fig. 1, illustration of breeding male and female, showing sexual dimorphism of caudal filament morphology; 360, fig. 9, illustrations of caudal filament with damage and regeneration (original description, type locality – French Guiana, coastal swamp, ‘Grand Pripris’ [see ‘Remarks’], sexual dimorphism of electric organ and EOD). - Hopkins, 1991: 153-154, figs. 1-2, drawings of holotype, black and white photographs of preserved specimens (French Guyana, description of type locality and type series, invalid as original description but includes nomination of holotype, see ‘Remarks’). -Costa & Campos-da-Paz, 1992: 117 (listing in description of B. janeiroensis ).

Brachyhypopomus pinnicaudatus . -Mago-Leccia, 1994: 48 (listing of Brachyhypopomus ). - Planquette et al., 1996: 398, color photograph of live individual (French Guiana, listing of Brachyhypopomus ). - Crampton, 1996a: 77, table 6.1.a, species list; 79, fig. 6.1 inset 25-26, 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). - Sullivan, 1997: 114 (redescription). - Crampton, 1998a; 821, table 4, 834, fig. 9, illustration of specimen, with EOD ( Brazil, Amazonas, species and EOD diversity). - Crampton, 1998b: 314, table 2, list of Brachyhypopomus ( Brazil, Amazonas, hypoxia tolerance). - Crampton, 1999: 17 ( Brazil, Amazonas, Mamirauá Reserve, listing of species). - Hopkins, 1999: 1218, fig. 1, drawings of breeding male and female, showing sexual dimorphism of caudal filament morphology (electric organ morphology and impedance matching). -Albert & Crampton, 2003: 495 ( Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, catalog of hypopomids). - Goulding et al., 2003: 177, color photograph of live individual ( Peru, río Madre de Dios; catalog of fishes). -Triques & Khamis, 2003: 63 (diagnosis against, in description of B. jureiae ). -Loureiro & Silva, 2006: 667 (diagnosis against, in description of B. bombilla ). - Giora et al., 2008: 162 (diagnosis against, in description of B. draco ). -Giora & Malabarba, 2009: 63 (diagnosis against, in description of B. gauderio ). -Sullivan & Hopkins, 2009: 183 (listing in description of B. bullocki ). -Kirschbaum & Schugardt, 2002: 562, figs. 3-4, black and white photographs of free embryo after hatching, larva at beginning of exogenous feeding, juvenile, and adult (gymnotiform reproduction). - Crampton & Albert, 2006: 672, fig. 23.8 (inset 10), color photograph of head of live individual with EOD, position in phylogenetic tree; 681, notes on EODs [survey of gymnotiform species and EOD diversity]. -Crampton, 2011: 176, table 10.2, species list; 179, figs. 10.2- 10.3, phylogeny, geographical and ecological distributions (gymnotiform biology). - Mol, 2012: 598 ( Suriname, catalog of fishes). -de Queiroz et al., 2013: 545, table 1 ( Brazil, rio Madeira, lago Cuniã, listing of fish species). -Crampton & Ribeiro, 2013: 238, color photograph of live individual ( Brazil, rio Madeira, listing of hypopomids). - Carvalho, 2013: 181-185, figs. 41-43, position in phylogeny (phylogenetic systematics of Rhamphichthyoidea ). - Sullivan et al., 2013: 27, fig. 10, color photograph of preserved intact and damaged/regenerated specimen (comparison to B. bennetti and B. walteri ). - Cardoso et al., 2015: 214 ( Brazil, Amazonas, cytogenetics). - Tagliacollo et al., 2016: 28, fig. 5 (phylogeny of Gymnotiformes ). - Crampton et al., 2016: 1-66, table 1, 3-4, figs. 1-7, 18-20 (phylogeny, biogeography and ecology of Brachyhypopomus ).

Diagnosis. Brachyhypopomus pinnicaudatus is diagnosed from congeners by the following combination of characters: prominent pale stripe along middorsal region present, vs. absent in all congeners except B. arrayae , B. beebei , B. belindae , B. gauderio , and B. verdii ); anal-fin rays 176-196, vs. 200-230 in B. beebei and B. belindae ; precaudal vertebrae 18-21, vs. 24-26 in B. verdii . Brachyhypopomus pinnicaudatus exhibits similar pigmentation and overlapping meristic counts and morphometric proportions with some populations of B. arrayae and B. gauderio . Brachyhypopomus pinnicaudatus can be distinguished from B. arrayae by the absence of a contact between a small ascending process on the endopterygoid and the orbitosphenoid vs. a contact between these two bones in B. arrayae (see diagnosis for B. arrayae for further details). Brachyhypopomus pinnicaudatus can be distinguished from B. gauderio by the presence of a medial bridge on the posterior portion of the basihyal, vs. absence in B. gauderio (see diagnosis for B. gauderio for further details).

Description. Head and body shape, and pigmentation illustrated in Figs. 1i and 38 . Meristic and morphometric data for examined specimens presented in Tables 2-5 and 18. Body moderate to deep in depth. Head short to moderate in length and moderate to deep in depth. Dorsal profile of head straight to slightly convex from occiput to snout, ventral profile of head approximately straight between operculum and snout, snout rounded. Eye moderate in size. Upper jaw with slight to moderate sigmoidal angle between premaxillary and maxillary portions in lateral view. No accessory electric organ over operculum. Pectoral fin of moderate width, pectoral-fin rays 13-16 (median of 15 in populations from coastal drainages of French Guiana; mode of 14 in population from rio Amazon of Brazil). Precaudal vertebrae 18-22 (mode of 20 in populations from coastal drainages of French Guiana; mode of 19 in population from rio Amazon of Brazil), including 1-2 transitional vertebrae. Anal-fin origin slightly (<0.25 HL distance) anterior to, or near, tip of pectoral fin. Anal-fin rays 177-196 (median of 184 in populations from coastal drainages of French Guiana; mode of 190 in population from rio Amazon of Brazil). Dorsal rami of recurrent branch of anterior lateral line nerve not visible. Middorsal region of body scaled. Rows of scales above lateral line 4-6 (mode 5). Lateral line continuous. Epidermal canals almost entirely absent; present in posterior half of body in form of an irregular, meandering, and sometimes bifurcating horizontal depigmented groove, on either side of dorsal surface in dorsal portions of flank; and as very sparse single or sometimes parallel double depigmented grooves either side of, but mostly dorsal to, lateral line. Three bilateral horizontal columns of electrocytes at anal-fin terminus, and at a mid-point between anal-fin terminus and tip of caudal filament in immature, mature female, and mature male specimens. Caudal filament short to moderate in length.

Coloration. ( Figs. 1i , 38 ). Background pale tan to dark brown. Pigmentation highly variable. Dorsal region with prominent depigmented or lightly pigmented stripe extending along midline from occipital region to base of caudal filament, or deep into caudal filament, bordered by prominent dark horizontal wavy reticulated lines from which short irregular patches extend ventrally. Dorsal pigmentation pattern strongly resembles that of B. gauderio , but pale depigmented stripe is more conspicuous. Irregular small dark patches or horizontally elongated spots often extend along lateral line. Ventral flank usually without irregular broken vertical bands and vertically elongated spots, especially over anal-fin pterygiophores, as often present in B. gauderio . Caudal filament darker than body, with irregular dark markings or bands along entire length. 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 with light scattering of brown chromatophores, especially in posterior portion of anal-fin. Color in live individuals similar to preserved specimens, with opercular region usually rosy due to underlying gills.

Size. Moderate adult size, largest specimen examined 208 mm TL, 142 mm LEA (n = 993). Largest male specimen examined 208 mm TL, 142 mm LEA (n = 23). Largest female specimen examined 156 mm TL, 118 mm LEA (n = 32).

Sexual dimorphism. Sexually mature males attain slightly larger sizes, and develop much broader caudal filaments than immature individuals and breeding females ( Figs. 38 a-b), but do not exhibit an elevated number of horizontal bilateral columns or vertical rows of electrocytes. Instead breeding males exhibit clearly enlarged electrocytes relative to immature specimens and females. Tip of caudal filament in breeding males often with paddle-like compression, commonly with end free of electrocytes (in some cases with electrocyte-free portion extending anteriorly for up to 20% of caudal-filament length). Hopkins et al. (1990) and Hopkins (1991) provide detailed notes on secondary sexual dimorphism of EO, electrocyte anatomy, and the EOD. No known sexual dimorphism in pigmentation.

Geographic distribution. Bolivia, Brazil, Peru, and French Guiana ( Fig. 39 ). Brachyhypopomus pinnicaudatus is widespread in eastern portions of the lowland Amazon, as far west as the confluence of the rio Japurá and rio Solimões near Tefé, and throughout the rio Madeira drainage. Specimens have also been collected from the rio Mearim drainage of Maranhão, Brazil, some 700 km SE of the mouth of the Amazon, and (based on photographs from Matavelli et al. 2015), from unspecified localities in the rio Munim basin, further SE (identified incorrectly as Rhabdolichops sp. ). Populations are also known from freshwater systems along much of the coast of French Guiana. Museum lots from localities further west along the northern coast of South America are not known although Mol (2012) reports B. pinnicaudatus from the Commewijne River in eastern Suriname.

Population variation: We found complete overlap in the range of meristic counts ( Tables 2-5) and morphometric measurements ( Table 18), and observed similar pigmentation among populations of B. pinnicaudatus from the eastern portions of the Amazon basin, and from the region of the type locality in coastal swamps of French Guiana. These observations, in combination with molecular data ( Crampton et al., 2016), support the hypothesis that all populations we have assigned to B. pinnicaudatus are members of a single geographically widespread species, which is morphologically and genetically distinct from its allopatric sister species, B. gauderio , and from all other congeners.

Ecological notes. In the Amazon basin Brachyhypopomus pinnicaudatus occurs primarily in floodplain systems of intermediate conductivity (30-90 μScm-1) and high conductivity (90-250μScm 1), especially those with turbid water. Records for low-conductivity (5-30 μScm-1) clearwater and blackwater rivers are mostly confined to near their confluence with major whitewater rivers (e.g. at the confluence of the rio Negro and rio Tefé with the Amazon River), although specimens are known from the rio Tapajós upstream of its mouthbay (ria) lake. Throughout its range B. pinnicaudatus is usually encountered in floating or rooted macrophytes along the margins of lakes, channels and swamps ( Crampton, 1996a; 1998a; 2011; Crampton &Albert, 2006; Crampton & Ribeiro, 2013; de Queiroz et al., 2013; Hopkins, 1991). Brachyhypopomus pinnicaudatus is able to tolerate seasonal or intermittent hypoxia by undertaking aerial gill respiration ( Crampton, 1998b; Hopkins, 1991). Hopkins (1991) describes the nature of aerial gill respiration of B. pinnicaudatus : “We noted in containers not oxygenated by bubbling, H. pinnicaudatus would rise to the surface every few minutes, take bubbles of air and lodge them in the gill chamber, which became noticeably flared as a result, and return to the bottom. Gentle pressure to the sides of the head would cause the release of several bubbles of air.”. Hopkins (1991) also describes the expanded size of the gill chamber in B. pinnicaudatus relative to congeners from normoxic systems, which “extends far toward the ventral midline where the two chambers meet at a septum. The secondary lamellae of the respiratory gill are well developed; the respiratory folds are very broad and thin, making them highly efficient in the uptake of oxygen from water”. Breeding occurs during the rising and high water period in populations from Amazonian floodplain floating macrophytes ( Crampton, 1996a, 165), and during the rainy seasons in populations from coastal French Guiana ( Hopkins et al., 1990). 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).

Co-occurring congeners: In the region of the type locality in coastal French Guiana, B. pinnicaudatus occurs in sympatry with B. beebei , B. brevirostris , and B. regani . In the Amazon basin (excluding the rio Madeira), B. pinnicaudatus occurs in sympatry and ecological syntopy with B. belindae , B. beebei , B. bennetti , B. brevirostris , B. flavipomus , B. hamiltoni , B. regani , and B. walteri , and in allotopy with B. batesi , B. hendersoni , and B. sullivani (except in terra firme-floodplain ecotones). In the rio Madeira basin B. pinnicaudatus is known to occur in sympatry and syntopy with B. arrayae , B. beebei , B. bombilla , B. brevirostris , B. cunia , and B. walteri , and in allotopy with B. alberti and B. sullivani .

Local names. Bolivia: cuchillo; Brazil: sarapó; French Guiana: poisson couteau (French) and multiple creole/ Amerindian names ( Planquette et al., 1996); Peru: macana.

Remarks. Comments on original description: Hopkins (1991), in the journal Copeia, provided a description of B. pinnicaudatus (as Hypopomus pinnicaudatus ). However, this description was preceded by a paper in the journal Brain, Behavior and Evolution ( Hopkins et al., 1990), which uses the name H. pinnicaudatus , comments that it is a “new species” (p. 350), specifies a type locality and type series (including repository information) (p. 351), provides an illustration (p. 352), and includes diagnostic notes by way of a comparison of sexual dimorphism to congeners (p. 365). Consequently, Hopkins et al. (1990), must be considered the valid authority ( ICZN, 1999, paragraphs 11.5.1, 13.1.1, and 16.1). Hopkins et al. (1990) evidently intended the Copeia paper to also be published in 1990 and provided a statement on p. 350: “A formal species description can be found in Hopkins [1990].” ( Hopkins [1990] is cited “in press” in Copeia in the bibliography). This statement does not in itself constitute a valid disclaimer to availability of the name, but rather makes the name H. pinnicaudatus available by indication ( ICZN, 1999, paragraph 13.1.2). No holotype was nominated by Hopkins et al. (1990) from a list of what must be considered syntypes. The “ holotype ” listed by Hopkins (1991) (ANSP 163463) is hereby designated as lectotype. Further, several “ paratypes ” lots listed by Hopkins (1991) that are not listed among the syntypes listed in Hopkins et al. (1990) must be excluded from the type series.

Material examined. 1,154 specimens. Bolivia. Beni (localities from rio Madeira dr., Amazonas dr.). AMNH 39848, 7, 68-103 mm, Pampa de Meio, ca. 12 km SE Costa Marques, affl. rio Guaporé, affl. río Mamoré, 12°34′00″S, 064°12′42″W. AUM 23504, 1, 85 mm, AUM 23643, 3, 124-127 mm, mun. Vaca Díez, affl. lago Tumi Chucua , affl. río Beni, ca. 11°07′S, 066°11′W . CAS 72216, 3, 112- 165 mm, Reyes , 24 mi. NE Rurrenabaque, río Beni, 14°17′42″S, 067°20′27″W . CBF 10260 , 1 , immature, 102 mm , CBF 10261 , 1 , immature, 100 mm, mun. Riberalta, stream nr. lago de San José , floodplain of río Beni, 10°54′47″S, 065°59′49″W . CBF 10262 , 1 , male, 157 mm , CBF 10263 , 1 , female, 115 mm , CBF 10264 , 1 , immature, 115 mm , CBF 10265 , 1 , immature, 101 mm , CBF 10266 , 1 , female, 111 mm , CBF 10267 , 1 , immature, 125 mm , UF 177343 , 1 , immature, 111 mm , UMSS 7025 , 1 , male, 119 mm , UMSS 7026 , 1 , female, 81 mm , UMSS 7027 , 1 , male, 106 mm , UMSS 7028 , 1 , female, 108 mm , UMSS 7029 , 1 , immature, 78 mm , UMSS 7030 , 1 , female, 95 mm , UMSS 7031 , 1 , female, 70 mm , UMSS 7032 , 1 , immature, 86 mm, mun. Riberalta, swamp nr. lago de San José , floodplain of río Beni, 10°54′45″S, 065°59′46″W . INHS 37118, 1, 97 mm, borrow pit, río Apere, aff río Mamoré , ca. 14°29′S, 065°40′W . INHS 37244, 1, 67 mm, 41 km E Estación Biológica del Beni, on rd. to San Ignacio de Moxos, río Chevejecure, affl. río Apere , affl. río Mamoré , ca. 14°22′S, 065°29′W . MNHN 1998- 1047, 2 (of 5), 123-142 mm, Trinidad , río Beni, ca. 14°50′S, 064°54′W . NMW 65039, 1, 102 mm TL, 80 mm LEA (paralectotype of B. brevirostris ), rio Guaporé, affl. río Mamoré , no coordinates . UF 81877 , 1 , 54 mm, Renez prov., stream, 1 km S Magdalena, río Itonomas, affl. río Machupo, affl. río Guaporé , affl. río Mamoré , ca. 13°16′S, 064°04′W . UF 82508 , 4 , 44-108 mm, pond 25 km N San Javier, río Mamoré , ca. 14°24′S, 064°56′W . UF 148445 , 1, 100 mm, prov. Iténez, río Blanco, nr. Bella Vista, affl. rio Guaporé, affl. río Mamoré , ca. 13°16′S, 063°41′W . UMMZ 66417, 2, 128-139 mm, Reyes and lagoons nr. Reyes , 24 mi. NE Rurrenabaque, affl. río Beni, ca. 14°17′S, 067°20′W . UMMZ 204434, 13, 52-90 mm, pool, Pampa do Meio, ca. 12 km SE Costa Marques (Brazil), río Iténez ( río Guaporé ), affl. río Mamoré , 12°34′00″S, 064°12′42″W . UMMZ 205102, 1, 158 mm, Arroyo Grande at mouth, ca. 1 km N Guayaramerín, affl. río Mamore , 10°48′00″S, 065°24′36″W . USNM 305593 , 1 , 85 mm, prov. Ballivia, lago Normandia, 40 km E San Borja, río Matos, affl. río Apere, affl. río Mamoré , ca. 14°55′S, 066°18′W . Pando. FMNH 106648, 1, 75 mm, río Manuripi, ca. 12 km upstream Puerto Rico, río Manuripi, affl. río Orthon, affl. río Madre de Dios , affl. río Beni, affl. rio Madeira , Amazonas dr., ca. 11°09′06″S, 067°33′41″W . Santa Cruz (localities from río Mamoré, affl. rio Madeira, Amazonas dr.). UF 82159 , 11 , 66-139 mm, 41 km SSE Concepción, affl. río San Martin , affl. rio Guaporé , ca. 16°37′S, 061°47′W . UF 82171 , 1 , 88 mm, prov. Velasco, 5.5 km N San Miguel, affl. río Paraguas, affl. río Iténez ( río Guaporé ), ca. 16°45′S, 060°59′W . UF 82189 , 1 , 75 mm, prov. Velasco, 71 km N San Jose de Chiquitos, río San Diablo, affl. río Itonam, affl. río San Martín , affl. río Guaporé , ca. 17°18′S, 060°35′W . ZUEC 7100, 1, 114 mm, Quimone, 45.4 km W San José de Chiquitos, río Quimone , affl. río San Pablo , 17°42′48″S, 062°08′56″W . Brazil. Amapá. MNRJ 12175 , 3 , 83-191 mm, mun. Mazagão, rio Miri nr. Mazagão- Macapá, rio Amazonas estuary, Amazonas dr., ca. 00°06′S, 051°17′W . MNRJ 12176 , 1, 165 mm, mun. Amapá, Fazenda Modelo do Aporema, rio Aporema, L bank, rio Araguari dr., ca. 01°03′N, 050°40′W . NRM 32240, 39, 38-85 mm, stream at Aldeia Cunene, rio Oiapoque dr., 04°01′08″N, 051°37′06″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 1998.3.12.108-116, 9 (1 female, 110 mm, 8 immature), mun. Tefé , Ilha Panamim , rio Solimões nr. Tefé , 03º17′38″S, 64º41′16″W . BMNH 1998.3.12.117-118, 2, immature, Mamirauá Reserve, cano do lago Rato , 03º02′41″S, 064º51′26″W . BMNH 1998.3.12.119, 1, immature, 120 mm, MCP 45398 , 1 , female ( CS), 116 mm, Mamirauá Reserve , lago Juruá Grande, 03º01′51″S, 064º51′07″W . BMNH 1998.3.12.120-122, 3, immature, 111-118 mm, Mamirauá Reserve, cano do lago Mamirauá , 03º03′51″S, 64º51′05″W . BMNH 1998.3.12.123-124, 2 (1 female, 134 mm, 1 male, 163 mm), Mamirauá Reserve, lago Pirarara , 02º57′04″S, 64º50′04″W . BMNH 1998.3.12.125-126, 2, immature, 150-178 mm, Mamirauá Reserve, lago Saracura , 02º58′34″S, 64º55′34″W . BMNH 1998.3.12.127, 1, male, 158 mm, Mamirauá Reserve , cano dos Lago Curuçá, 03º04′31″S, 64º48′52″W . BMNH 1998.3.12.128, 1, immature, 153 mm, Mamirauá Reserve, Ressaca do Pau , 03º02′03″S, 64º52′13″W . BMNH 1998.3.12.129, 1, male, 169 mm, Mamirauá Reserve, cano do lago Sapucaia , 03º04′07″S, 64°48′32″W . BMNH 1998.3.12.130- 132, 3 male, 154-159 mm, MCP 45328 , 1 , immature, 89 mm, Mamirauá Reserve, Ressaca do Caetono , 02º50′15″S, 064º55′50″W . IDSM 445, 1, 116 mm, Mamirauá Reserve , lago Sumaumeirinha I, 02º48′27″S, 065º04′37″W . IDSM 446, 4, 82-133 mm, MCP 45275 , 2 (1 female, 148 mm, 1 male, 208 mm) , MCP 45437 , 3 (1 female, 144 mm, 2 male, 139-143 mm), Mamirauá Reserve , lago Secretaria, 03º07′12″S, 064°47′49″W . INHS 67200, 1, lago Canta Galos, lago Janauari , ca. 03°13′S, 060°00′W . INHS 70412, 1, 98 mm, INHS 71295, 1, 141 mm, lago Janauari , 03°13′S, 060°00′W . INPA 4389 , 4 , 92-135 mm , INPA 9119 , 8 , INPA 19939 , 39 , 23-141 mm, Paraná do Rei, Ilha Careiro, rio Amazonas floodplain, 03°12′W, 059°44′W . INPA 4738 , 1, 113 mm , INPA 4806 , 25 , 76-142 mm , INPA 4871 , 35 , 32-135 mm , INPA 19941 , 1 , 77 mm , INPA 19946 , 1 , 84 mm , INPA 19955 , 6 , 75-130 mm , MZUSP 24967 , 1, 147 mm , MZUSP 75572 , 4 , 121-142 mm, lago do Castanho, Ilha Janauacá, rio Solimões floodplain, 03°43′S, 060°26′W . INPA 9946 , 24 , 86-140 mm, Reserva Mamirauá, lago Caetano, 02º50′58″S, 064º55′42″W . INPA 13568 , 2 , 33-59 mm , INPA 15771 , 2 , 77-86 mm , INPA 16700 , 1, 136 mm, lago Comprido, Ilha da Marchantaria, rio Amazonas floodplain, ca. 03°14′S, 059°56′W . INPA 17119 , 2 , 112-138 mm, lake nr. Sacado da Santa Luzía, rio Purus , 04°42′48″S, 062°22′26″W . INPA 17120 , 2 , 71-96 mm, Paranã 2, nr. Arumã, rio Purus , 04°46′24″S, 062°11′35″W . INPA 19942 , 4 , 93-147 mm, rio Negro , Amazonas dr., no coordinates . MCP 45276 , 3 (1 immature, 82 mm, 1 female, 129 mm, 1 male, 110 mm), Mamirauá Reserve , lago Curuçá Redondo, 03º06′13″S, 064°49′06″W . MCP 45277 , 3 (1 immature, 120 mm, 1 female, 103 mm, 1 male, 104 mm), Mamirauá Reserve , lago Curuçá Aberto, 03º06′07″S, 064°49′10″W . MCP 45278 , 4 (1 immature, 120 mm, 1 female, 156 mm, 2 male, 153-177 mm), Mamirauá Reserve , lago Curuçá Comprido, 03º05′31″S, 064°48′58″W . MCP 45279 , 1 , immature, 134 mm , MCP 45410 , 1 , immature, 101 mm , MCP 45435 , 66 , 33-161 mm, Mamirauá Reserve , cano do lago Mamirauá, 03º05′15″S, 064°48′03″W . MCP 45280 , 2 , female, 127-136 mm , MCP 45281 , 1 , male, 158 mm, Mamirauá Reserve, Ressaca da Vila Alencar , 03º07′41″S, 064°48′04″W . MCP 45351 , 2 , female, 127-136 mm, Mamirauá Reserve , lago Juruazinho, 03º02.58′S, 064º51.01′W . MCP 45370 , 2 , female (2 CS) 122-125 mm, Mamirauá Reserve , lago Araçazinho, 02º59′35″S, 064º51′33″W . MCP 45409 , 1 , immature, 88 mm, Mamirauá Reserve , lago Promessa, 03º04′29″S, 064°47′02″W . MCP 45433 , 2 (1 immature, 115 mm, 1 female 145 mm), Mamirauá Reserve , lago Araçazinho, 02º59′35″S, 064º51′33″W . MCP 45436 , 1 , male, 173 mm, Mamirauá Reserve, Ressaca do Itu , 02º49′51″S, 064º57′11″W . MCP 45438 , 1 , immature, 113 mm , MCP 45455 , 3 (1 immature, 67 mm, 1 female, 135 mm, 1 male, 147 mm) , MCP 46928 , 2 , female (2 CS), 143-148 mm, Mamirauá Reserve , lago Secretaria, 03º07′12″S, 064°47′49″W . MCP 45469 , 12 , 58-143 mm, mun. Tefé, floodplain lake, Ilha Panamim, rio Solimões, nr. Tefé, rio Solimões , 03°19′29″S, 064°38′37″W . MCZ 8354, 26, 76-83 mm, MCZ 9421, 1, 137 mm, MCZ 9424, 1, 48 mm, mun. Parintins, Villa Bella, rio Amazonas at Parintins , ca. 02°38′S, 056°54′W . MCZ 78165, 1, 95 mm, lago Jacaretinga, nr. Careiro de Várzea, rio Amazonas , 03°13′00″S, 059°49′41″W . MPEG 1110, 11, 67-147 mm, MPEG 1112, 1, 70 mm, MPEG 1117, 6, 53-115 mm, mun. Iranduba, rio Solimões , ca. 03°17′S, 060°11′W [coordinates for Iranduba]. MPEG 22740, 1, 86 mm, Mamirauá Reserve, lago do Pagão , 03º02′51″S, 064°50′23″W . MZUSP 6326 (part), 3, 83-136 mm, lago Castro, Boca do rio Purus, rio Purus , ca. 03°42′S, 061°28′W . MZUSP 6475 , 1 , lago Jacaré, upstream Manacapurú, rio Solimões floodplain, ca. 03°40′S, 060°48′W . MZUSP 165854 , 3 , 84-133 mm, mun. Manaus, lago Hyanuary [lago do Janauari], rio Amazonas floodplain, ca. 03°13′S, 060°00′W . USNM 229915 , 2 , 107-135 mm , USNM 306833 , 40 , 27-137 mm , USNM 306866 , 4 , 55-150 mm, São José, lago do Castanho, lago Janauacá, rio Amazonas floodplain, ca. 03°26′S, 060°17′W [coordinates taken from center of lago Janauacá]. USNM 306678 , 1 , 75 mm , USNM 306870 , 3 , 116-133 mm, lago Murumuru, nr. Curral, lago Janauacá, rio Amazonas floodplain, ca. 03°25′S, 060°16′W . USNM 306693 , 3 , 68-102 mm , USNM 306735 , 3 , 118-130 mm , USNM 306872 , 1 , 80 mm, Paraná do lago Janauacá, entrance of lago do Castanho, rio Amazonas floodplain, no coordinates . USNM 306694 , 1 , 87 mm, Ressaca da Ilha da Marchantaria, rio Amazonas floodplain, ca. 03°14′S, 059°56′W . USNM 306749 , 1, 116 mm, furo [artificial channel] between lago Murumuru and Paraná de Janauacá, rio Amazonas floodplain, ca. 03°25′S, 060°16′W . USNM 306785 , 1, 116 mm, lago Janauari, rio Amazonas floodplain, ca. 03°13′S, 060°00′W . USNM 306789 , 5 , 48-145 mm , USNM 306811 , 7 , 100- 121 mm, lago Janauari, nr. entrance, rio Amazonas floodplain, ca. 03°13′S, 059°59′W . USNM 306877 , 1 , 36 mm, lago Canta Galos, lago Janauari, rio Amazonas floodplain, ca. 03°13′S, 060°00′W . USNM 306948 , 1 , 54 mm, lago Terra Preta, lago do Janauari, rio Amazonas floodplain, ca. 03°13′S, 060°00′W . Maranhão. MNRJ 12222 , 2 , 77-80 mm, mun. Ararí, lago Malhada Grande, rio Mearim dr., ca. 03°27′S, 044°46′W . MNRJ 12223 , 2 , 98-113 mm, mun. Ararí, lago Capivara, rio Mearim dr., ca. 03°27′S, 044°46′W . Pará. (localities from Amazonas dr.). ANSP 194516, 4, 75-106 mm, mun. Porto de Moz , beach, R bank rio Xingu 3 km downstream Porto de Moz, rio Xingu , 01°43′54″S, 052°15′16″W . CAS 33502, 1, 136 mm, SU 54500 , 1, 143 mm, Ajamury, lago Grande, rio Amazonas floodplain, ca. 02°16′S, 54°17′W . FMNH 54550, 3, 84-126 mm, Santarém, rio Amazonas , ca. 02°25′S, 054°42′W . INPA 19961 , 7 , 72-107 mm, lago Salgado, rio Cumuní, affl. rio Trombetas , ca. 01°26′S, 055°55′W . MCP 28564 , 1 , 64 mm, mun. São Domingos do Capim, igarapé do Onze, ca. 11 km São Domingos do Capim on Belém-Brasília hwy., affl. rio Guamá , affl. Baía de Marajó, ca. 01°45′S, 047°41′W . MCP 49403 , 11 , mun. Curuá, Lago Preto, Ilha São Luiz, rio Amazonas , 02°06′22″S, 055°10′17″W . MCP 49407 , 15 , UF 238558 , 28 , 116-209 mm , UF 238559 , 15 , 110-209 mm , UF 238560 , 25 , 57-155 mm , UF 238561 , 1 , 68 mm , UF 238562 , 46 , 48-142 mm , UF 238563 , 36 , 66-125 mm, mun. Santarém, Lago de Santana, Ilha Marimarituba, rio Amazonas , 02°11′13″S, 055°02′21″W . UF 238569 , 1 , 58 mm , UF 238571 , 2 , 49-57 mm , UF 238572 , 23 , 131-206 , UF 238573 , 4 , 131-209 , UF 238574 , 7 , 72- 109 , UF 238576 , 9 , 68-115 m , UF 238578 , 1 , 16 mm , UF 238579 , 9 , 76-91 mm , UF 238581 , 19 , 67-139 mm, mun. Santarém, lago Pajau, rio Amazonas, 02˚11’29″S, 054˚51’28″W. MCZ 9415, 1, 127 mm, MCZ 45095, 2, 125-132 mm, rio Xingu at Porto de Moz , ca. 01°45′S, 052°10′W . MCZ 9432, 1, 108 mm, MCZ 9435, 4, 98-137 mm, MCZ 165862, 11 (part), 40-114 mm, mun. Santarém, Santarém and environs, rio Tapajós , ca. 02°26′S, 54°41′W . MPEG 1130, 2, 97-107 mm, MPEG 2816, 2, 50-127 mm, MPEG 3723, 1, 88 mm, mun. Cachoeira do Arari, Taperebá, rio Goapi , llha de Marajó, affl. Baía do Marajó , ca. 01°00′S, 048°57′W [coordinates for Cachoeira do Arari]. MPEG 1860, 11, 37-102 mm, mun. Óbidos, rio Amazonas nr. Óbidos , ca. 01°54′S, 055°26′W . MPEG 2437, 2, 90-112 mm, mun. Cachoeira do Arari, 1 km upstream Taperebá, rio Goapi, llha de Marajó, affl. Baía do Marajó , ca. 01°00′S, 048°57′W [coordinates for Cachoeira do Arari]. MPEG 5819, 1, 97 mm, mun. Almeirim, São Raimundo, rio Amazonas , ca. 01°32′S, 052°31′W [coordinates for Almeirim]. MPEG 9942, 1, 125 mm, MPEG 9943, 1, 97 mm, MPEG 9958, 6, 47-132 mm, MPEG 9962, 1, 63 mm, MPEG 9987, 1, 125 mm, MPEG 10162, 4, 97-130 mm, mun. Portel, Floresta Nacional Caxiuanã, affl. rio Anapú , affl. rio Pará , affl. Baía de Marajó, ca. 01°44′S, 051°26′W . MUSM 565 , 1, 134 mm, lago Uruira, Oriximinã, rio Trombetas-Amazonas floodplain, ca. 01°46′S, 055°51′W [coordinate for Oriximinã]. MZUSP 5033 , 1 , 87 mm, mun. Cachoeira do Arari, Ilha de Marajó, rio Arari , affl. Baía de Marajó, ca. 01°00′S, 048°57′W . MZUSP 22894 , 1 , 92 mm, igarapé Caraparú, affl. rio Guamá , aff, Baía de Marajó, ca. 01°23′S, 048°08′W . MZUSP 23216 , 20 , 78-108 mm LEA, lago Ururiá [L. Urarirá], Oriximiná, rio Amazonas floodplain nr. mouth rio Trombetas , ca. 01°53′S, 055°52′W . SU 54490 , 1 , 57 mm , SU 54498 , 1 , 88 mm, Uruará brook into rio Tapajós, Santarém , ca. 02°26′S, 054°42′W [coordinates for Santarém]. SU 54493 , 1, 109 mm, igarapé do Sapucua [probably affl. lago Sapucuá] at Ayereua, affl. río Trombetas , ca. 01°49′S, 056°05′W . SU 54501 , 1, 130 mm, lago Grande, rio Amazonas floodplain, ca. 02°16′S, 54°17′W . SU 54614 , 1 , 99 mm, Alemquer [Alenquer] pond affl. rio Amazonas , ca. 01°57′30″S, 54°44′18″W [coordinates for Alenquer]. Rondônia (localities from rio Madeira dr., Amazonas dr.). INPA 9719 , 2 , 148- 155 mm , INPA 9728 , 3 , 125-145 mm, ca. 15 km Guajará Mirim, rio Pacaás Novos, affl. rio Mamoré , ca. 10°51′S, 065°16′W . INPA 19943 , 15 , 53-92 mm, rio Mamoré , upstream Surprêsa, ca. 11°53′S, 064°59′W . INPA 19953 , 3 , 34-88 mm, rio Mamoré, just upstream Guajará Mirim , ca. 10°47′S, 065°20′W . INPA 19957 , 1, 148 mm, Surprêsa, at rio Guaporé- Mamoré confl., ca. 11°53′S, 064°59′W . MPEG 1116, 6, 77-100 mm, rio Pacaás Novas, Guajará Mirim, affl. rio Mamoré , ca. 10°51′S, 065°16′W . MPEG 1121 (part), 1, 85 mm, rio Pacaás Novos , 20 km upstream Guajará Mirim, ca. 10°56′15″S, 065°16′29″W . UFRO-I 6484, 34, 43-145 mm, UFRO-I uncat. (field number CUN2009061202 ), 1, 58 mm, UFRO-I uncat. (field number CUN2009072001 ), 1, 54 mm, Furo Variante, lago Cuniã, rio Madeira floodplain, 08°21′18″S, 063°30′11″W . UFRO-I 6486, 11, 68-144 mm, lago Cuniã, nr. ICMBio base, rio Madeira floodplain, 08°19′40″S, 063°30′11″W . UFRO-I 6489, 2, 86-161 mm, UFRO-I 6498, 1, 124 mm, lago Cuniã, nr. ICMBio base, rio Madeira floodplain, 08°19′20″S, 063°30′14″W . UFRO-I 6491, 4, 38-111 mm, lago Cuniã, nr. igarapé do Campo, rio Madeira floodplain, 08°19′09″S, 063°28′44″W . UFRO-I 6493, 3, 141-151 mm, Arrozal do lago, lago Cuniã, rio Madeira floodplain, 08°19′36″S, 063°29′59″W . UFRO-I 6500, 3, 55-148 mm, lago Cuniã, rio Madeira floodplain, 08°19′45″S, 063°28′06″W . UFRO-I 6502, 28, 78-135 mm, lago Cuniã, rio Madeira floodplain, 08°21′10″S, 063°30′26″W . UFRO-I 6510, 21, 81-180 mm, mouth of rio Cautário, affl. rio Guaporé, affl. rio Mamoré , 12°10′51″S, 064°34′04″W . UFRO-I 6511, 1, 113 mm, igarapé do Campo, lago Cuniã, rio Madeira floodplain, 08°19′14″S, 063°28′05″W . UFRO-I 7927, 8 (2 immature, 96-111 mm, 6 female, 90-107 mm), mun. Porto Velho, lago Cuniã, rio Madeira floodplain, 08°19′S, 063°28′W . USNM 348864 , 1, 119 mm, Brazil-Bolivia border region between Guajará-Mirim and Mato Grosso, rio Guaporé, affl. rio Mamoré , ca. 13°46′S, 061°04′W . French Guiana. Cayenne. ANSP 163463, 1 (lectotype), male, 125 mm, ANSP 163464, 1 (paralectotype), male, 149 mm, ANSP 163465, 1 (paralectotype), female, 119 mm, ANSP 164474, 1 (paralectotype), male, 156 mm, BMNH 1990.10.23.1-3, 3), 93- 108 mm, FMNH 98817, 1 (paralectotype), 116 mm, MBUCV-V 20221 , 3 , 82-100 mm, MNHN 1989-1209, 3 (paralectotypes), NMW 90321, 5, 115-139 mm, UMMZ 216032, 3, 48-68 mm [originally 96-106] mm , USNM 301966 , 1 (paralectotype), 114 mm , USNM 301967 , 1 (paralectotype), female, 114 mm, coastal swamp, ‘ Grand Pripris’, 3.5 km NW center of old Kourou, ca. 100m N old Route Nationale 1, Kourou River dr., 05°10′45″N, 052°40′00″W . CU 71933, 1, male, 170 mm, FMNH 98818, 3, 124- 161 mm, swampy border, Kaw River, ca. 3.5 km SW Kaw, River Kaw dr., ca. 04°27′N, 052°10′W . USNM 301968 , 1 , 64 mm, swamp, old Rn-1 Hwy., nr. city of Kourou, Kourou River dr., ca. 05°10′N, 052°39′W . Peru. Madre de Dios. (localities from río Madre de Dios, affl. río Beni, affl. rio Madeira, Amazonas dr.). MUSM 2470 , 1 , Parque Nacional del Manu , Pakitza, río Manu , ca. 12°52′S, 069°16′W . MUSM 2874 , 2 , Reserva Nacional ( RN) Tambopata, cocha Redonda, no coordinates . MUSM 2981 , 1 , 90 mm, Planchón, N Puerto Maldonado, río Manuripi, affl. río Orthon , ca. 12°17′S, 069°09′W . MUSM 3521 , 2 , Reserva Nacional Tambopata, La Colpa, río Tambopata , no coordinates . MUSM 4198 , 4 , RN Tambopata, no coordinates . MUSM 9265 , 10 , 94-171 mm , MUSM 9847 , 1, 170 mm , MUSM 16004 , 1, 123 mm , MUSM 16169 , 1 , MUSM 16181 , 1, 195 mm, lago Tres Chimbadas, RN Tambopata, río Tambobata , 12°47′26″S, 069°20′31″W . MUSM 16610 , l, 109 mm, lago Valencia, río Madre de Dios floodplain, ca. 12°25′S, 068°46′W . MUSM 16712 , 2 , 142-147 mm , MUSM 16743 , 1, 140 mm, Tambopata, lago Copamanu, ca. 12°50′S, 069°17′W . MUSM 19991 , 1, 149 mm, Los Amigos Biostation, río Madre de Dios floodplain, ca. 12°33′S, 070°07′W . MUSM 20046 , 1, 150 mm, Manu, no coordinates . MUSM 20184 , 4 , Mavila, río Los Amigos , no coordinates . MUSM 20588 , 2 , MUSM 21390 , 10 , MUSM 21483 , 1 , Tambopata, Pozo Pedro, río Los Amigos , 12°33′40″S, 070°06′36″W . MUSM 21731 , 2 , MUSM 21779 , 3 , Pozo Santa Elena, no coordinates . MUSM 22101 , 1 , Tambopata, Aguajal Oeste, ca. 12°00′S, 070°40′W . TCWC 13983.01, 2, 73-87 mm, lago Tres Chimbadas, río Tambopata , 12°47′29″S, 069°20′54″W . TCWS 13985.02, 2, 86-115 mm, lago Tres Chimbadas, río Tambopata , 12°47′04″S, 069°20′29″W . USNM 263859 , 4 , 70-135 mm, RN Tambopata, Laguna Chica, 12°50′30″S, 069°17′30″W . USNM 264110 , 5 , 42-102 mm , USNM 387400 , 1 , 91 mm, NR Tambopata, Laguna Cocococha, 5.1 km E Explorer’s Inn, 12°49′00″S, 069°16′30″W .

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. 38. Brachyhypopomus pinnicaudatus. a. MCP 45469 (WC13.310701b), female, 143 mm (head in lateral view, and body in lateral and dorsal view, specimen fixed in formalin); b. MCP 45278 (WC13020698), male, 167 mm TL (body in lateral view, specimen fixed in formalin and preserved in EtOH). Brazil, rio Solimões-Japurá confluence, Amazonas dr. Note sexual dimorphism in caudal-filament length and height, and feather-like structure at caudal filament terminus in male. Scale bars = 5 mm.

Fig. 39. Collection records for Brachyhypopomus pinnicaudatus (circles) and B. verdii (squares). Holotype locations are marked with open symbols. Elevation data refers to altitude above mean sea level (see Fig. 2 for legend).