| Hypopomidae (Bluntnose knifefishes) |
| 11.1 cm TL (male/unsexed); 10 cm TL (female) |
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benthopelagic; freshwater; pH range: 5.2 - 5.5 |
| South America: upper rio Madeira basin in Brazil and Bolivia. |
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Anal soft rays: 172-191. Brachyhypopomus alberti is distinguished from other species of the genus Brachyhypopomus by the following combination of characters: absence of depigmented stripe along middorsal region of body (vs. prominent pale uninterrupted middorsal stripe from occipital region to base of caudal filament in B. arrayae, B. beebei, B. belindae, B. gauderio, B. pinnicaudatus, and B. verdii); 20-22 precaudal vertebrae (vs. 15-19 in B. batesi, B. benjamini, B. bennetti, B. bombilla, B. bullocki, B. cunia, B. diazi, B. hendersoni, B. menezesi, B. provenzanoi, B. regani, and B. sullivani); anal fin with 182-202 rays (vs. 226-293 in B. brevirostris); presence of continuous or discontinuous dark vertical or diagonally oriented bands or saddles on body surface dorsal to lateral line, often extending across lateral line into ventral lateral surface (vs. absence of oblique bands or saddles on body surface dorsal to lateral line in B. draco, B. flavipomus, B. jureiae, and B. palenque); 3 bilateral columns of electrocytes at the anal-fin terminus (vs. 4-5 in B. janeiroensis and B. occidentalis (except some populations in Colombia and Venezuela); absence of dark suborbital stripe (vs. presence in B. walteri). It differs from most but not all specimens of B. hamiltoni by having a higher number of pectoral-fin rays 15-16 (mode 16) (vs. 12-15 (mode 13) (only 2 of 18 measured specimens of B. hamiltoni exhibited an overlapping number of pectoral-fin rays with B. alberti). It can be differentiated from B. hamiltoni by the absence of the first of five branchiostegal rays (vs. presence in B. hamiltoni Mago-Leccia) (Ref. 116763). |
| The type series was sampled in tropical forest and savanna near Riberalta, Bolivia from small low-conductivity clearwater and blackwater terra firme streams. Found mostly commonly in marginal root mats, and in emergent or submerged aquatic vegetation. Recorded water parameters at the sampling sites included the following: conductivity 5-15 μS/cm, dissolved oxygen 3.0-5.0 mg/l, temperature 22-24°C, and pH 5.2-5.5. Co-inhabits in geographical sympatry and ecological syntopy with the following species occurring in terra firme stream: B. brevirostris, B. sullivani, and B. walteri. In the region of the type locality, it is allotopic with whitewater floodplain species such as B. arrayae, B. bombilla, and B. pinnicaudatus. It co-occurs in geographical sympatry with its sister species B. arrayae, but the species exhibit a noteworthy difference in ecological distribution. B. alberti occupies the low conductivity (ca. 5-15 μScm-1) terra firme forest and savanna streams, while B. arrayae mainly inhabits higher-conductivity whitewater floodplain systems (ca. 150 μScm-1 at the time of sampling). B. alberti was collected together with B. arrayae (and also B. pinnicaudatus) in the lower reaches of terra firme streams, at the ecotone with the río Beni floodplain (Ref. 116763). |
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Not Evaluated (N.E.) Ref. (130435)
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| harmless |
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