Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Actinopteri (ray-finned fishes) > Osteoglossiformes
(Bony tongues) > Mormyridae
Etymology: Marcusenius: Becasue of J. Marcusen, author of "Zur Phauna des Schwarzen Meeres", 1867; ichthyologist; gracilis: Marcusenius gracilis is more slender than the other Ivorian and many of the West African Marcusenius species, hence its specific name gracilis (Ref. 93659)
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic; depth range - m (Ref. ), usually - m (Ref. ). Tropical; 0°C -
Africa: Comoé River (Ref. 93659).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 22.1 cm SL male/unsexed; (Ref. 93659)
Morphology | Morphometrics
soft rays: 31 - 35. Diagnosis: Marcusenius gracilis has notched teeth (Ref. 93659). A much smaller dorsal to anal fin base ratio distinguishes Marcusenius thomasi from M. gracilis, being 0.7 vs. 0.79; M. mento is characterized by a higher number of lateral line scales, more than 76 vs. less than 77 for M. gracilis; M. ussheri differs by its lower number of lateral line scales, less than 65 vs. more than 70 in M. gracilis, its smaller pectoral fin length to head ratio, which is less than 0.9, and its usually deeper caudal peduncle, the ratio caudal peduncle depth to length less than 0.3 vs. more than 0.32 in M. gracilis (Ref. 93659). Marcusenius furcidens is distinguished by a combination of its higher count of dorsal fin rays, being more than 29 vs. less than 30 in M. gracilis, a longer dorsal fin, a higher ratio of dorsal to anal fin base, being 0.78, and a greater body depth; males of M. furcidens have no distinct kink in the anal fin base, in contrast to the males of M. gracilis; relative to the P phase of its EOD, M. furcidens EODs have a stronger N phase amplitude than those of M. gracilis (Ref. 93659).
Found in a series of stagnant pools; some pools were quite deep and inhabitated by hippos who could dive; the river banks were high and steep, and difficult to climb when wet, revealing high water and violent current at some times in the year (Ref. 93659).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Kramer, B., 2013. Differentiation in morphology and electrical signalling in four species of para- and sympatric Marcusenius (Teleostei: Mormyridae) from Côte d’Ivoire, West Africa. Marine and Freshwater Behaviour and Physiology, 46(2):105-133. (Ref. 93659)
IUCN Red List Status (Ref. 124695)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01000 (0.00244 - 0.04107), b=3.04 (2.81 - 3.27), in cm total length, based on all LWR estimates for this body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.1 ±0.4 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.).
Vulnerability (Ref. 59153
): Low to moderate vulnerability (26 of 100) .