Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Teleostei (teleosts) >
Gymnotiformes (Knifefishes) >
Hypopomidae (Bluntnose knifefishes)
Etymology: Hypopygus: Greek, hypo = under + Greek, pyge = tail (Ref. 45335); nijsseni: The specific epithet, nijsseni, is a patronym in honour of Hans Nijssen for his contribution to Neotropical ichthyology (Ref. 88778).
Eponymy: Dr Han Nijssen (1935–2013) was a Dutch ichthyologist who was an expert on the genus Corydoras. [...] (Ref. 128868), visit book page.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic. Tropical
South America: Hypopygus nijsseni is known only from small streams in the vicinity of Tefé (Ref. 88778).
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 9.6 cm TL male/unsexed; (Ref. 88778)
Short description
Identification keys | Morphology | Morphometrics
Hypopygus nijsseni is diagnosed from congeners by the following combination of characters: the total number of anal-fin rays (145–152 versus 102–135 in H. hoedemani, H. lepturus, and H. minissimus; 155–174 in H. cryptogenes), the presence of the sixth infraorbital bone (versus absence in H. hoedemani, H. lepturus, and H. minissimus), the presence of oblique bands (versus absence in H. minissimus), the presence of scales at midbody (versus absence in H. minissimus), the dorsal rami of intermittent branch of anterior lateral line nerve visible as two black parallel lines (versus not visible in H. ortegai), the head length (13.2–15.3% of LEA versus 12.6–13.9 in H. ortegai), the distance at the nape (12.5–13.8% of LEA versus 11.0–12.5 in H. ortegai), the total number of pectoral fin rays (ten to 12 versus 12–16 in H. isbruckeri), the number of scales above the lateral line (five to six versus seven to eight in H. isbruckeri), and the distance from the anus to the anal fin (7.9–9.4% of LEA versus 10.0–12.0 in H. neblinae) (Ref. 88778).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
de Santana, C.D. and W.G.R. Crampton, 2011. Phylogenetic interrelationships, taxonomy, and reductive evolution in the Neotropical electric fish genus Hypopygus (Teleostei, Ostariophysi, Gymnotiformes). Zool. J. Linn. Soc. 163:1096-1156. (Ref. 88778)
IUCN Red List Status (Ref. 130435: Version 2024-1)
Threat to humans
Harmless
Human uses
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5039 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00372 (0.00139 - 0.00994), b=3.06 (2.83 - 3.29), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.1 ±0.4 se; based on size and trophs of closest relatives
Fishing Vulnerability (Ref.
59153): Low vulnerability (10 of 100).
![Image of Hypopygus nijsseni (Nijssen\](/images/thumbnails/gif/tn_HYPOPOT0.gif "Image of Hypopygus nijsseni (Nijssen\")
