Bate's Bluntnose Knifefish

distribution

Distribution: Middle reaches of Amazon, Brazil, and upper Negro River, Colombia (Crampton et al., 2016 b).

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

biology_ecology

Ecological notes. The type series was collected from the lower, seasonally flooded reaches of low-conductivity blackwater rainforest streams that flow into lago Tefé, and lago Amanã (large blackwater ria lakes of similar conductivity to the streams). Most specimens were encountered in marginal root mats or submerged leaf-litter along stream edges. The following water parameters were recorded at the time of sampling: conductivity 10 - 30 µScm- 1, dissolved oxygen 2.0 - 5.2 mgl- 1, temperature 24.3 - 27.0 ° C, and pH 4.5 - 6.0. During the high water period this species disappears from the flood-swollen lower stream reaches, probably due to declining dissolved oxygen levels, and apparently moves upstream to terra firme stream reaches above the seasonal river-floodplain flood influence. Breeding occurs during the early rising-water period, which in the Tefé region corresponds to the rainy season (WGRC unpublished data). Records of B. batesi outside the area of the type series are all from low-conductivity blackwater rainforest streams. Stomach contents of specimens from the type locality comprise aquatic insect larvae (primarily Chironomidae), and other small aquatic invertebrates (WGR

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 a and 8. Meristic and morphometric data for examined specimens presented in Tables 2 - 6. Body shallow in depth. Head short to moderate in length and shallow in depth. Dorsal profile of head approximately straight from occiput to snout, ventral profile of head approximately straight with convex and concave portions, snout truncated. Eye moderate 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 61 (n = 1). Pectoral fin narrow to moderate in width, pectoral-fin rays 12 - 13 (mode 13). Precaudal vertebrae 16 - 18 (mode 18) including 1 - 2 (mode 2) transitional vertebrae. Anal-fin origin substantially posterior (between 0.25 and 0.75 HL distance) to tip of pectoral fin. Anal-fin rays 159 - 173 (median 168). Dorsal rami of recurrent branch of anterior lateral line nerve visible. Entire middorsal region of body scaled, although scales in anterior third of body sparse and mostly occluded by skin. Rows of scales above lateral line 5 - 6 (mode 5). Lateral line complete. Sparse groove

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

description

urn: lsid: zoobank. org: act: 728 CA 0 A 5 - F 5 C 5 - 465 F- 8793 - D 1176 B 3 E 7 F 57 (Figs. 1 a, 8; Tables 2 - 6)

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