Brachyhypopomus flavipomus, Crampton & de Santana & Waddell & Lovejoy, 2016

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 : 717-721

Brachyhypopomus flavipomus , new species urn:lsid:zoobank.org:act:8368D549-9BE7-45FC-BE01-05742AFA0851

( Figs. 1f , 24 ; Tables 2-5, 13)

Brachyhypopomus sp. 1 . - Crampton, 1996a: 77, table 6.1.a, species list; 79, fig. 6.1 inset 15-16, 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). - Crampton, 1998b: 314, table 2, list of Brachyhypopomus ( Brazil, Amazonas, hypoxia tolerance).

Hypopomidae sp. 1. - Crampton, 1998a: 821, table 4, 834, fig. 9, drawing of adult specimen, with EOD ( Brazil, Amazonas, species and EOD diversity).

Brachyhypopomus sp. A . - Crampton, 1999: 17 ( Brazil, Amazonas, Mamirauá Reserve, listing of species). - Crampton & Albert, 2006: 672, fig. 23.8, position in phylogenetic tree; 681, notes on EODs (gymnotiform species and EOD diversity). -Crampton et al., 2008: 231, fig. 6, black and white photograph of head of live individual ( Brazil, Amazonas, adaptations to hypoxia).

Brachyhypopomus sp. “fla”. -Crampton 2011: 176, table 10.2, species list; 179, figs. 10.2-10.3, phylogeny, geographical and ecological distributions (gymnotiform biology).

Brachyhypopomus n. sp. FLAV. - Cardoso et al., 2015: 214 ( Brazil, Amazonas, cytogenetics).

Brachyhypopomus sp. “flavipomus ”. - Crampton et al., 2016: 1-66, table 1, 3-4, figs. 1-7, 18-20 (phylogeny, biogeography and ecology of Brachyhypopomus ).

Holotype. MCP 45366 , immature, 92 mm TL, 73 mm LEA, Brazil, Amazonas , mun. Alvarães , Mamirauá Reserve [Reserva de Desenvolvimento Sustentável Mamirauá], Ressaca do Caetono , rio Solimões-rio Japurá floodplain, Amazonas dr., 02º50′15″S, 064º55′50″W, 11 May 1997, W. Crampton & J. Oliveira.

Paratypes. 57 specimens, localities from Amazonas dr., collected by W. Crampton & J. Oliveira. Brazil. Amazonas (localities listed from the Mamirauá Reserve are in rio Solimões-Japurá floodplain, mun. Alvarães ). BMNH 1998.3.12.25, 1, female, 113 mm, 20 Jan 1995 , BMNH 1998.3.12.26 and 28-41, 15 unsexed, 75-107 mm, 20 Jan 1995, BMNH 1998.3.12.27, 1, immature, 93 mm, 20 Jan 1995, BMNH 1998.3.12.43-44, 2, immature, 90-108 mm, 11 Apr 1994, MCP 45265 , 1 , female, 98 mm, 14 Mar 2001 , Mamirauá Reserve, cano do lago Rato , 03º02′41″S, 064º51′26″W. BMNH 1998.3.12.42, 1, female, 117 mm, 10 Apr 1994 , INPA 9942 , 21 , 58-87 mm, Oct 1993 , INPA 18365 , 1 , immature, 83 mm, 11 May 1997 , Mamirauá Reserve, Ressaca do Caetono , 02º50′15″S, 064º55′50″W. INPA 18363 , 2 , immature, 62-73 mm, 2 Jul 1996 , MCP 45349 , 1 , immature, 85 mm, 4 Jul 1996 , Mamirauá Reserve, cano do lago Arauaé , 03º02′52″S, 064º50′04″W. INPA 18364 , 1 , immature, 79 mm, 11 Jul 1996 , MCP 45350 , 2 , immature, 80-82 mm, 11 Jul 1996 , Mamirauá Reserve, cano do lago Sapucaia , 03º04′07″S, 064°48′32″W. INPA 18366 , 1 , immature, 76 mm, 18 Jun 1999 , MCP 45425 , 1 , immature, 62 mm, 1 May 1999 , Mamirauá Reserve, lago Secretaria , 03º07′12″S, 064°47′49″W. INPA 18367 , 1 , immature, 70 mm, 24 Jul 1999 , MCP 45266 , 1 , female, 91 mm, 19 Mar 2001 , Mamirauá Reserve, cano do lago Mamirauá , 03º06′40″S, 064°47′52″W. INPA 18368 , 1 , immature, 53 mm, 25 May 1999 , MCP 45367 , 1 , male, 104 mm, 17 May 1997 , Mamirauá Reserve, Ressaca da Vila Alencar, 03º07′41″S, 064°48′04″W. MCP 45405 , 1 , immature, 73 mm, Mamirauá Reserve , cano do lago Mamirauá , 03º04′29″S, 064°48′29″W, 16 Jun 1998 . MCP 45406 , 1 , immature, 48 mm, Mamirauá Reserve, Paraná do Apara , 03º06′50″S, 064°47′48″W, 23 Jun 1998 .

Non-types. 150 specimens, localities from Amazonas dr. Brazil. Amazonas (localities listed from the Mamirauá Reserve are in rio Solimões-Japurá floodplain, mun. Alvarães ). IDSM 450, 1, 107 mm, IDSM 455, 5, 64-99 mm, MCP 45368 , 14 , 58-83 mm, Mamirauá Reserve , cano do lago Rato , 03º02′41″S, 064º51′26″W . MCP 45264 , 1 , female, 86 mm, Mamirauá Reserve , lago Geraldo, 03º06′53″S, 064°49′06″W . MCP 45329 , 2 , immature, 69-74 mm , MCP 45365 , 11 (3 immature, 86-97 mm, 5 female [3CS], 85-107 mm, 3 male [1CS], 91-97 mm), Mamirauá Reserve, Ressaca do Caetono , 02º50′15″S, 064º55′50″W . MCP 45364 , 1 , immature, 91 mm, Mamirauá Reserve, cano do lago Rato , 03º02′41″S, 064º51′26″W . MCP 45453 , 1 , female, 98 mm, Mamirauá Reserve , lago Secretaria, 03º07′12″S, 064°47′49″W . MPEG 22743, 5, 60-104 mm, Mamirauá Reserve, cano do lago Rato , 03º02′50″S, 064º51′27″W . MZUSP 23402 , 1 , 88 mm, igarapé Tucuxi, affl. rio Ati-Paraná, NW Fonte Boa, affl. rio Solimões , ca. 02°06′S, 066°28′W . MZUSP 23425 , 1 , 62 mm, lago Buiuçu, affl. rio Ati-Paraná, affl. rio Solimões , ca. 02°06′S, 066°28′W . Colombia. Amazonas. USNM 216857 , 1 , 66 mm, Leticia, río Amazonas , 04°13′S, 069°56′W . Peru. Loreto. ANSP 179835, 1, 71 mm, caño Moena and mouth of its affl. caño Ullpa, affl. río Itaya, affl. río Amazonas , 03°46′19″S, 073°14′16″W . INHS 39732, 1, 74 mm, INHS 52030, 1, 79 mm, INHS 53873, 2, 76-95 mm, caño Moena, affl. río Itaya , 03°46′20″S, 073°14′17″W . INHS 94214, 3, 56-62 mm, caño Ushpa, affl. río Itaya , ca. 03°48′S, 073°16′W . INHS 56227, 1, 60 mm, caño Ullpa, 2-3 mi. upstream from mouth and village Ullpa, affl. río Itaya , 03°47′37″S, 073°14′44″W . MUSM 6959 (part), 3, (1 female, 77 mm, 2 male, 90-92 mm), Isla Muyuy, cocha Amazonas, affl. río Amazonas , ca. 03°54′S, 073°14′W . MUSM 44760 , 1 , immature, 64 mm, nr. Jenaro Herrera, floodplain lake, río Ucayali, 04°54′18″S, 073°43′12″W . MUSM 44770 , 37 (32 immature, 37-82 mm, 5 female, 54-100 mm), nr. Jenaro Herrera, cocha Capite , floodplain lake, río Ucayali, 04°51′21″S, 073°40′24″W . NRM 13522 (part), 1, 69 mm, Sacarita del Tuyé, opposite Pebas, río Ampiyacu , ca. 03°20′S, 071°49′W . UF 114641 , 1 , 55 mm , UF 148052 , 1 , immature, 75 mm, Reserva Nacional ( RN) Pacaya Samiria, cocha Yanayacu, affl. río Pacaya , affl. río Ucayali, 05°23′29″S, 074°31′21″W . UF 126156 , 1 , 52 mm , UF 126327 , 1 , 69 mm , UF 128883 , 2 , 40-53 mm , UF 128981 , 8 , 47-79 mm , UF 129035 , 1 , 76 mm , UF 129047 , 1 , 70 mm , UF 129086 , 6 , 37-74 mm , UF 129144 , 8 , 47- 102 mm , UF 129187 , 6 , 45-80 mm , UF 129414 , 1 , 52 mm , UF 129798 , 2 , 67-82 mm, RN Pacaya Samiria, río Pacaya , affl. río Ucayali, ca. 05°16′S, 074°27′W . UF 126238 , 5 , 63- 81 mm , UF 129006 , 1 , immature, 70 mm , UF 129797 , 1 , 65 mm, RN Pacaya Samiria, cocha Sapote, affl. río Pacaya , affl. río Ucayali, 05°20′14″S, 074°29′40″W . UF 129010 , 1 , immature, 58 mm, RN Pacaya Samiria, río Pacaya , affl. río Ucayali, 05°16′12″S, 074°30′09″W . UF 129012 , 1 , immature, 53 mm, RN Pacaya Samiria, río Pacaya , affl. río Ucayali, 05°16′44″S, 074°31′06″W . UF 148053 , 2 (1 immature, 74 mm, 1 female, 78 mm), RN Pacaya Samiria, caño Tamara, affl. río Pacaya , affl. río Ucayali, 05°16′39″S, 074°29′39″W . UF 148547 , 3 (2 immature, 75-76 mm, 1 female, 75 mm), NN Pacaya Samiria, caño Yarina, affl. río Pacaya , affl. río Ucayali, 05°19′20″S, 074°30′14″W . UF 148549 , 1 , male, 95 mm, RN Pacaya Samiria, cocha Sapote, affl. río Pacaya , affl. río Ucayali, 05°20′15″S, 074°29′40″W . UF 148554 , 1 , immature, 84 mm, RN Pacaya Samiria, río Pacaya , affl. río Ucayali, 05°18′15″S, 074°30′10″W . UF 148555 , 2 , female, 84-92 mm, RN Pacaya Samiria, cocha Yanayacu, affl. río Pacaya , affl. río Ucayali, 05°18′14″S, 074°26′12″W .

Diagnosis. Brachyhypopomus flavipomus is diagnosed by the presence of conspicuous patches of shiny yellow guanine on the operculum and anterior to pectoral-fin base in live individuals, vs. absence in all congeners.

Description. Head and body shape, and pigmentation illustrated in Figs. 1f and 24 . Meristic and morphometric data for examined specimens presented in Tables 2-5 and 13. Body moderate to broad in depth. Head moderate in length and depth. Dorsal profile of head straight to slightly convex from occiput to snout, ventral profile of head approximately straight between operculum and snout, snout triangular. Eye moderate to large in size. Upper jaw with slight sigmoidal angle between premaxillary and maxillary portions in lateral view. No accessory electric organ over operculum. Gill filaments on first gill arch 33-39 (median 34, n = 5). Pectoral fin narrow to moderate in width, pectoral-fin rays 11-13 (mode 12). Precaudal vertebrae 18-20 (mode 19), with 1-2 (mode 1) transitional vertebrae. Anal-fin origin slightly (<0.25 HL distance) anterior to, or near, tip of pectoral fin. Anal-fin rays 175-186 (median 179). Dorsal rami of recurrent branch of anterior lateral line nerve not visible. Middorsal region of body scaled. Rows of scales above lateral line 5-6 (mode 5). Lateral line continuous. Sparse depigmented epidermal canals; as an irregular interrupted single groove either side of dorsal midline along most of posterior half body, scratch like marks dorsal to and near lateral line almost absent, present sporadically and sparsely in some specimens. Three bilateral horizontal columns of electrocytes at anal-fin terminus and at or near a mid-point between anal-fin terminus and tip of caudal filament in immature, mature female, and mature male specimens. Number of electrocyte columns sometimes increases to four posterior to mid-point between anal-fin terminus and tip of caudal filament, before tapering to 2-3 distally. Caudal filament short to moderate in length.

Coloration. ( Figs. 1f , 24 ). Background dark brown dorsally fading to pale yellow to tan ventrally. Background of region of body over body cavity below lateral line whitish to yellow in live individuals, pale tan in preserved specimens. Dorsal region without prominent depigmented pale stripe extending along midline from occipital region to base of caudal filament. Prominent pair of irregular horizontal lines formed by aggregations of dark chromatophores either side of dorsal region, visible both dorsally and laterally (in upper part of flank) in anterior third of body, from which short irregular dark patches extend dorsally. Some irregular dark markings along lateral line and over pterygiophores in posterior half of body, but flank otherwise marked only with irregular scatterings of chromatophores; banding absent. Caudal filament darker than body, with irregular dark markings or bands along entire length. Head with very pale background color ventrally, darker dorsally. Irregular dark chromatophores scattered over head, reaching highest density on dorsal surface of head and anterior to eye. 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. Color in live specimens ( Fig. 1f ) similar to preserved ones, but with very conspicuous shiny yellow patches of guanine over operculum (forming one or two vertical yellow lines) and anterior to pectoral-fin base (forming a vertically elongated patch) and with conspicuous white or pale yellow color below lateral line over body cavity. Yellow guanine patches and white-yellow background color over body cavity fade soon after fixation. Live individuals with posterior portion of opercular region (posterior to guanine patch) rosy due to underlying gills.

Size. Small adult size, largest specimen examined 117 mm, 89 mm LEA (n = 208). Largest male specimen examined 104 mm TL, 77 mm LEA (n = 7). Largest female specimen examined 117 mm TL, 89 mm LEA (n = 21).

Sexual dimorphism. Females reach larger body size than males. Males in breeding condition have somewhat deeper and longer caudal filaments than immature specimens or breeding females but do not exhibit an elevated number of horizontal bilateral columns or vertical rows of electrocytes. Instead breeding males exhibit slightly enlarged electrocytes relative to immature specimens and females. Breeding males without paddle-like lateral compression at caudal filament tip. No known sexual dimorphism in pigmentation.

Geographic distribution. Brazil and Peru ( Fig. 25 ). Known only from whitewater floodplain habitats along the main stem of the Amazon River of the upper and central Amazon, from the río Ucayali-río Marañón confluence in the west to the rio Solimões (Amazonas) – rio Japurá confluence in the east. Ecological notes. Brachyhypopomus flavipomus is restricted to whitewater floodplain habitats where it is encountered throughout the year in floating macrophytes. It is most abundant in sheltered floodplain lakes surrounded by high levee forest, but has a patchy distribution, and varies in abundance at a given site from year to year (WGRC unpublished data). See description of B. belindae for water quality parameters of the area of the type locality. During the early rising water period B. flavipomus also occurs in leaf litter along the margins of newly flooded forest. Brachyhypopomus flavipomus is able to tolerate protracted periods of hypoxia at high water by aerial gill respiration ( Crampton, 1998b), and its gill lamellae are greatly expanded in comparison to species from normoxic system (Crampton et al., 2008). Brachyhypopomus flavipomus breeds during the rising and high water period ( Crampton, 1996a, 165). Stomach contents of specimens from the type locality comprise aquatic insect larvae, microcrustacea, and other small aquatic invertebrates – with a predominance of Chironomidae larvae ( Crampton, 1996a: 136).

Co-occurring congeners: Brachyhypopomus flavipomus is known to co-occur in geographical sympatry and ecological syntopy with the whitewater floodplain-occurring species B. beebei , B. belindae , B. bennetti , B. brevirostris , B. hamiltoni , B. pinnicaudatus , B. regani , and B. walteri . It also exhibits allotopic distributions across parts of its range with: B. batesi , B. benjamini ¸ B. hendersoni , B. sullivani , and B. verdii .

Etymology. The specific name is an adjective with alternative endings -us, -a, -um, derived from flavus, Latin adjective = yellow; and pomus, latinized from Greek πῶμα = lid, cover. In reference to the conspicuous patches of yellow guanine on the operculum of live individuals.

Local names. Brazil: sarapó; Peru: macana.

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. 24. Brachyhypopomus flavipomus. MCP 45366 (WC19.110597), holotype, immature, 92 mm TL (head, and body in lateral and dorsal view, specimen fixed in formalin and preserved in EtOH); Brazil, rio Solimões/rio Japurá confluence, Amazonas dr. Scale bars = 5 mm.

Fig. 25. Collection records for Brachyhypopomus flavipomus (circles). Holotype location is marked with an open symbol. Elevation data refers to altitude above mean sea level (see Fig. 2 for legend).