Teleostei (teleosts) >
Osteoglossiformes (Bony tongues) >
Mormyridae (Elephantfishes)
Etymology: Heteromormyrus: Greek, heteros = other + Greek mormyros = a kind of fish similar to Boops sp. (Ref. 45335); longilateralis: The specific name longilateralis is in reference to the long lateral line (Ref. 85059).
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic. Tropical
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 17.2 cm SL male/unsexed; (Ref. 85059)
Short description
Identification keys | Morphology | Morphometrics
Dorsal spines (total): 0; Dorsal soft rays (total): 18 - 21; Anal spines: 0; Anal soft rays: 22 - 25. Diagnosis: Hippopotamyrus longilateralis can be distinguished by following characters: distance from dorsal fin origin to end of caudal peduncle 37.9-41.7% of standard length; predorsal length 61.2-64.9% of standard length; distance from tip of snout to anal fin origin 59.0-62.7% of standard length; caudal peduncle length 19.5-22.0% of standard length; head length 19.2-22.8% of standard length; snout length 45.7-54.8% of head length; body depth 20.3-24.5% of standard length; number of dorsal fin rays 18-21; number of anal fin rays 22-25; number of scales in a linear series along the lateral line row 74-80; number of scales around caudal peduncle 19-22; and bipolar, pentaphasic waveform of EOD pulse (Ref. 85059).
Description Head broadly rounded with a terminally positioned mouth, lower jaw protruding less forward than upper; body long and slender, laterally compressed (Ref. 85059). Dorsal fin origin set far back and behind that of anal fin, situated about two-thirds of standard length from snout, obliquely orientated with anterior portion of the fin higher than the posterior portion; number of dorsal fin rays 18-21; anal fin opposite dorsal fin but origin further anterior and also obliquely orientated, anteriorly lower and posteriorly higher, margin broadly rounded; number of anal fin rays 22-25 (Ref. 85059). Scales cycloid with reticulate striae, except in centre, extending anteriorly to operculum and pectoral fins; scales around caudal peduncle 19-22 (Ref. 85059). Caudal peduncle slender and subcylindrical over the entire length, usually slightly less than one-fifth in standard length; tail fin with broadly rounded lobes (Ref. 85059). EOD bipolar and pentaphasic, duration of the two main phases about 230 µs but whole pulse may last up to 5 milliseconds because of weak pre- and post-potentials (Ref. 85059).
Colouration: Dark brown with a vertical black band from dorsal origin that is only weak in most specimens (Ref. 85059). Colour in preservation dark to medium brown, often with milky-grey hue, especially where opaque 'mormyrid skin' is present (Ref. 85059).
Found along well-vegetated and steep banks of the river; they therefore possibly prefer undercut banks with structure such as roots (Ref. 85059).
Life cycle and mating behavior
Maturities | Reproduction | Spawnings | Egg(s) | Fecundities | Larvae
Sullivan, J.P.: Hopkins, C.D., S. Pirro, R. Peterson, A. Chakona, T.I. Mutizwa, C. Mukweze Mulelenu, F.H. Alqahtani, E. Vreven and C.B. Dillman, 2022. Mitogenome recovered from a 19th century holotype by shotgun sequencing supplies a generic name for an orphaned clade of African weakly electric fishes (Osteoglossomorpha, Mormyridae). ZooKeys 1129:163-196. (Ref. 128501)
IUCN Red List Status (Ref. 130435)
Threat to humans
Harmless
Human uses
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5002 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00562 (0.00251 - 0.01261), b=3.05 (2.85 - 3.25), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.2 ±0.3 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Fishing Vulnerability (Ref.
59153): Low vulnerability (11 of 100).
