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Characiformes (Characins) >
Distichodontidae (Distichodus)
Etymology: Nannocharax: Latin, nannus = small + Greek, charax = a marine fish without identification (Ref. 45335); usongo: Named in honor of Dr. Leonard Usongo, highly successful conservation biologist and supporter of numerous fish inventories in Cameroon (Ref. 80507).
Eponymy: Leonard Usongo is a Cameroonian biologist who has worked as a WWF Project Leader in his country. He was honoured as a “…highly successful conservation biologist and supporter of numerous fish inventories in Cameroon”. (Ref. 128868), visit book page.
Environment: milieu / climate zone / djupintervall / distribution range
Ekologi
; sötvatten pelagiska. Tropical; 6°N - 5°N, 6°E - 10°E
Africa: Cross River and Niger Delta (Ref. 80507).
Size / Vikt / Age
Könsmognad: Lm ? range ? - ? cm
Max length : 4.4 cm SL hane/ej könsbestämd; (Ref. 80507)
Short description
Bestämningsnycklar | Morfologi | Morfometri
Taggstrålar i ryggfenan (totalt) : 0; Mjukstrålar i ryggfenan (totalt) : 10 - 14; Taggstrålar i analfenan: 0; Mjukstrålar i analfenan: 10 - 12. Diagnosis: Nannocharax usongo is distinguished from all other described Nannocharax species by its very small distance between the posterior border of the anus and the articulation of first anal-fin ray (0.9–1.9 vs. 2.2–14.2% of standard length), its body coloration, which consist of 7–11 mostly big blotches along the lateral line often coalesced to one wide black band, and 7–12 small blotches along the dorsum (Ref. 80507).
Body shape (shape guide): elongated; Cross section: compressed.
Type specimens collected on logs in areas of relatively rapid water movement; logs had a very rugged surface due to being partially decomposed by wood eating Povilla (Ephemeroptera) larvae; individuals were spaced singly and moved very rapidly around log surface, but always with close contact to it and never reaching out into the free water column; first ray of pelvic fin very thick, which is adaptation to cling on wood in strong current; mouth subinferior and blunt (Ref. 80507).
Life cycle and mating behavior
Könsmognad | Reproduktion | Lek | Ägg | Fecundity | Larver
Dunz, A.R. and U.K. Schliewen, 2009. Description of two new species of Nannocharax Günther, 1867 (Teleostei: Characiformes: Distichodontidae) from the Cross River, Cameroon. Zootaxa 2028:1-19. (Ref. 80507)
IUCN Red List Status (Ref. 130435: Version 2024-2)
Threat to humans
Harmless
Human uses
Fiskeri: av potentiellt intresse
Verktyg
Special reports
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00447 (0.00189 - 0.01058), b=3.17 (2.96 - 3.38), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trofisk nivå (Ref.
69278): 3.1 ±0.4 se; based on size and trophs of closest relatives
Fishing Vulnerability (Ref.
59153): Low vulnerability (10 of 100).
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