Brachyhypopomus beebei

distribution

Distribution: Widespread through cis-Andean northern South America (Crampton et al., 2016 b).

Checklist of Gymnotiformes (Osteichthyes: Ostariophysi) and catalogue of primary types

biology_ecology

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, 1996 a; 1998 a; 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, 1996 a). 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

A taxonomic revision of the Neotropical electric fish genus Brachyhypopomus (Ostariophysi: Gymnotiformes: Hypopomidae), with descriptions of 15 new species

description

Description. Head and body shape, and pigmentation illustrated in Figs. 1 b 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 ( 90 μScm- 1). Caudal filament short to moderate in length. Coloration. (Figs. 1 b, 9). Background light tan or grey to dark brown. Head darker, especially dorsally. Dorsal region with prominent depigmented pale stripe extending along mid

A taxonomic revision of the Neotropical electric fish genus Brachyhypopomus (Ostariophysi: Gymnotiformes: Hypopomidae), with descriptions of 15 new species

diagnosis

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.

A taxonomic revision of the Neotropical electric fish genus Brachyhypopomus (Ostariophysi: Gymnotiformes: Hypopomidae), with descriptions of 15 new species