Brachyhypopomus verdii, 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 : 772-775

Brachyhypopomus verdii , new species urn:lsid:zoobank.org:act:3FC61943-7A01-40A4-A5D6-C7E296167CE0

( Fig. 45 ; Tables 2-5, 20)

Brachyhypopomus pinnicaudatus . -Chang & Ortega, 1995: 3, ( Peru, catalog of fishes).

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

Brachyhypopomus n. sp. VERD. - Elbassiouny et al., 2016: 401- 403, fig. 1 (description of mitogenome, position in phylogeny of Ostariophysi based on mitochondrial genomes).

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

Holotype. MUSM 35307 , female, 79 mm TL, 67 mm LEA, Peru, Loreto, mun. Maynas, Jenaro Herrera, stream, nr. Jenaro Herrera-Colonia Angamos rd. , affl. río Ucayali, Amazonas dr., 04º53′54″S, 073º38′22″W, 16 Jan 2004, W. Crampton, H. Ortega, R. Reis, F. Lima & J. Oliveira.

Paratypes. 41 specimens, localities from Amazonas dr. Peru. Loreto (localities listed from nr. Jenaro Herrera, are from the río Ucayali dr., mun. Requena ). MUSM 44683 , 4 (2 immature, 89-103 mm, 1 female, 79 mm, 1 male, 107 mm), stream nr. Jenaro Herrera , 04°53′35″S, 073°39′01″W, 11- 30 Jul 2009, W. Crampton, E. Correa Roldán, M. Guevara & J. Waddell. MUSM 44726 , 1 , female, 76 mm, forest stream 1.65 km Jenaro Herrera, affl. río Ucayali, Amazonas dr., 04°54′33″S, 073°39′26″W, 30 Jul 2009, W. Crampton, E. Correa Roldán, M. Guevara & J. Waddell. UF 148522 , 2 , immature, 82-106 mm, nr. Jenaro Herrera, stream in agricultural field, affl. quebrada Parnayari, ca. 04º54′S, 073º37′W, 14 Jan 2004, W. Crampton, H. Ortega, R. Reis, F. Lima & J. Oliveira. UF 148523 , 7 , immature, 84-109 mm, stream nr. Jenaro Herrera, 04°53′54″S, 073°38′21″W, 16 Jan 2004, W. Crampton, H. Ortega, R. Reis, F. Lima & J. Oliveira. UF 184011 , 1 , female, 107 mm, stream nr. Jenaro Herrera, 04°52′42″S, 073°38′51″W, 20 Jul 2009, W. Crampton, E. Correa Roldán, M. Guevara & J. Waddell. UF 184021 , 1 , immature, 66 mm, stream nr. Jenaro Herrera, 04°54′40″S, 073°39′29″W, 21 Jul 2009, W. Crampton, E. Correa Roldán, M. Guevara & J. Waddell. UF 184026 , 19 (4 immature, 67-87 mm, 6 female, 67-100 mm, 9 male, 79-120 mm), stream nr. Jenaro Herrera, 04°54′36″S, 073°39′44″W, 31 Jul 2009. W. Crampton, E. Correa Roldán, M. Guevara & J. Waddell. USNM 405580 , 3 , immature, 74-78 mm, stream nr. Jenaro Herrera, 04°54′15″S, 073°36′53″W, 25 Jul 2009, W. Crampton, E. Correa Roldán, M. Guevara & J. Waddell. USNM 405582 , 3 (2 immature, 83-104 mm, 1 female, 91 mm), stream nr. Jenaro Herrera, 04°54′49″S, 073°39′43″W, 31 Jul 2009, W. Crampton, E. Correa Roldán, M. Guevara & J. Waddell .

Non-types. 185 specimens, localities from Amazonas dr. Peru. Amazonas. FMNH 96997 , 1, 125 mm, Caterpiza , affl. río Santiago , affl. río Marañón , ca. 03°54′S, 077°42′W . Loreto (localities listed from nr. Jenaro Herrera, are from the río Ucayali dr., mun. Requena). ANSP 167724 , 4 , 65- 109 mm, swamp on path from Mishana village to Nauta rd. , affl. río Nanay , 03°53′12″S, 073°28′57″W . MUSM 3229 , 3 , stream nr. Jenaro Herrera , ca. 04°53′S, 073°39′W . MUSM 4449 , 2 , mun. Yurimaguas, San Ramón, río Marañón , ca. 04°54′S, 076°26′W . MUSM 44677 , 30 (14 immature, 33-110 mm, 10 female, 77-104 mm, 6 male, 88-111 mm), stream nr. Jenaro Herrera , 04°53′59″S, 073°38′51″W . MUSM 44764 , 27 (18 immature, 26-107 mm, 9 female, 61-109 mm), stream nr. Jenaro Herrera , 04°54′36″S, 073°39′58″W . UF 148520 , 19 (16 immature [3 CS], 38-105 mm, 2 female, 83-96 mm, 1 male, 106 mm), stream nr. Jenaro Herrera , ca. 04º53′S, 073º39′W . UF 148521 , 32 (28 immature, 45-109 mm, 3 female, 80-97 mm, 1 male, 109 mm), stream nr. Jenaro Herrera , 04°55′38″S, 073°39′10″W . USNM 405578 , 17 (9 immature, 49-114 mm, 6 female, 82-101 mm, 2 male, 98-114 mm), stream nr. Jenaro Herrera , 04°53′54″S, 073°38′23″W . USNM 405579 , 24 (14 immature, 44-100 mm, 4 female, 92-112 mm, 6 male, 92-115 mm), stream nr. Jenaro Herrera , 04°55′38″S, 073°39′14″W . USNM 405581 , 25 (15 immature, 55-95 mm, 4 female, 69-95 mm, 6 male, 93-110 mm), stream nr. Jenaro Herrera , 04°55′41″S, 073°38′46″W .

and to paratype specimens from the type region.

Diagnosis. Brachyhypopomus verdii is diagnosed from congeners by the following combination of characters: precaudal vertebrae 24-26, vs. 15-23 in all congeners except B. belindae and B. draco ; bilateral columns of electrocytes at the anal-fin terminus 3, vs. 4-5 in B. belindae ; continuous or discontinuous dark vertical or diagonally oriented bands or saddles present on body surface dorsal to lateral line, vs. absence of oblique bands or saddles on body surface dorsal to lateral line in B. draco .

Description. Head and body shape, and pigmentation illustrated in Fig. 45 . Meristic and morphometric data for examined specimens presented in Tables 2-5 and 20. Body shallow in depth. Head short and shallow to moderate in depth. Dorsal profile of head convex from occiput to snout, ventral profile of head convex between operculum and snout, snout rounded. Eye small to moderate in size. Upper jaw with moderate sigmoidal angle between premaxillary and maxillary portions in lateral view. Accessory electric organ (AEO) over operculum absent. Gill filaments on first gill arch 35-40 (median 37, n = 6). Pectoral fin narrow to moderate, pectoral-fin rays 13-17 (mode 15). Precaudal vertebrae 24-26 (mode 25), with 1-2 (mode 2) transitional vertebrae. Anal-fin origin slightly (<0.25 HL distance) posterior to tip of pectoral fin. Anal-fin rays 194-225 (median 208). 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 groove-like depigmented epidermal canals – as parallel crisscrossing lines either side of lateral line (mainly in posterior third of body), or branching ventrally from lateral line (mainly in mid-third of body); and as a pair of long irregular lines either side of dorsal surface in dorsal portion of flank, along posterior two thirds of body. Three bilateral horizontal columns of electrocytes at anal-fin terminus and at 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.

Size. Small adult size, largest specimen examined 125 mm TL, 107 mm LEA (n = 222). Largest male specimen examined 120 mm TL, 102 mm LEA (n = 32). Largest female specimen examined 112 mm TL, 95 mm LEA (n = 52).

Coloration. ( Fig. 45 ). Background light tan to brown. 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 – reaching or traversing lateral line in anterior third of body but reaching less than half distance from dorsal midline to lateral line posteriorly. Dorsal pigmentation pattern resembles that of B. gauderio and B. pinnicaudatus , but reticulated lines extending ventrally from either side of depigmented dorsal stripe are shorter and often only faintly visible in lateral view in posterior two thirds of body. Ventral flank otherwise marked only with small irregular dark spots. Very faint short vertical dark markings sometimes present over anal-fin pterygiophores in posterior half of body. 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, accentuated in posterior portion of anal-fin. Color in live individuals similar to preserved specimens, with opercular region usually rosy due to underlying gills.

Sexual dimorphism. Sexually mature males attain slightly larger sizes. Sexually mature males develop broader caudal filaments than immature individuals and breeding females ( Figs. 45 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. Breeding males with paddle-like lateral compression at caudal filament tip. No known sexual dimorphism in pigmentation.

Geographic distribution. Peru ( Fig. 39 ). Known only from tributaries of the río Marañón and río Ucayali in the upper Amazon basin.

Ecological notes. Known only from low-conductivity blackwater terra firme rainforest streams and swamps, where it is found in association with submerged roots and leaf litter. See description of B. benjamini for water quality parameters of the area of the type locality. Breeding occurs during the rainy season in the area of the type locality (approximately December to April) (JCW unpublished data). Stomach contents of specimens from the type locality comprise small aquatic invertebrates (JCW unpublished data).

Co-occurring congeners: In the region of the type locality in the lower río Ucayali, B. verdii occurs in sympatry and syntopy with B. beebei , B. benjamini , B. brevirostris , B. sullivani , and B. walteri . It exhibits an allotopic distribution to B. bennetti , B. flavipomus , B. hamiltoni , and B. regani .

Etymology. The specific name is a patronym (noun in the genitive case) in honor of Lorgio Verdi Olivares, Peruvian conservation biologist, for his support to WGRC and NRL.

Local name. Peru: macana.

Figures

Fig. 45. Brachyhypopomus verdii. a. UF 148520 (WC24.090104), paratype, male, 106 mm TL (head in lateral view, and body in lateral and dorsal view); b. MUSM 35307 (WC06.160104), holotype, female, 79 mm TL (body in lateral view). Peru, río Ucayali, Amazonas dr. Note sexual dimorphism in caudal-filament length and height. Specimens fixed in formalin and preserved in EtOH. 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).