Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Actinopteri (ray-finned fishes) > Synbranchiformes
(Spiny eels) > Mastacembelidae
Etymology: Mastacembelus: Greek, mastax, -agos = bite + Greek, emballo = to throw oneself (Ref. 45335); simbi: Named after "simbi" (simbi singular; basimbi plural) or "water spirit", once considered an ancient ancestor in the Bakongo region of Congo where the species is discovered. A noun in apposition..
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic. Tropical; 27°C - 29°C (Ref. 84205)
Africa: known only from the middle reach of the main channel of the lower Congo River from Lenga Lenga near the border with the Republic of Congo to just below Luozi (Democratic Republic of the Congo).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 7.8 cm SL male/unsexed; (Ref. 84205)
Morphology | Morphometrics
(total): 23 - 26;
soft rays: 46 - 56;
Vertebrae: 68 - 71. Distinguished from all other species of Mastacembelidae by the following characters: no pterosphenoid bone in the neurocranium; no supracleithral sensory canal; no post-temporal tubules; and an infraorbital series represented by the first infraorbital only. Can be further separated from all other members belonging to Mastacembelus crassus species complex by the following combination of characters (where +1 denotes the presence of a short spine covered by skin and not externally visible): 22-25+1 dorsal spines (vs. 18-21+ in Mastacembelus aviceps and Mastacembelus crassus; eye visible at the surface of the head and relatively well developed, eye diameter 10.0-15.3% HL (vs. 4.8-7.2% HL in Mastacembelus latens; fully pigmented with a color pattern characterized by an oblique bar on the cheek and a series of vertically oriented and irregularly shaped midlateral bars most often present along the body and always present in the post-anal region (vs. depigmented in Mastacembelus latens (Ref. 84205).
Found in shallow, marginal habitats among rocks and rock rubble close to rapids or fast flowing water. Appears to be sympatric with or at least in close proximity to, Mastacembelus brichardi, Mastacembelus brachyrhinus and Mastacembelus crassus in Lenga Lenga where the holotype and part of paratypes were collected. Also caught elsewhere with Mastacembelus congicus and Mastacembelus paucipinnis. A 6.12 cm SL female specimen had about 15-20, seemingly mature, ovarian eggs with a maximum size of about 1.0 mm diameter. The occurrence of these large eggs may indicate that reproductive activity occurs in July, the period when the specimens were collected. Sexually mature at about 6.0 cm SL (Ref. 84205).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Vreven, E.J. and M.L.J. Stiassny, 2009. Mastacembelus simbi, a new dwarf spiny eel (Synbranchiformes: Mastacembelidae) from the lower Congo River. Ichthyol. Explor. Freshwat. 20(3):213-222. (Ref. 84205)
IUCN Red List Status (Ref. 125652)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00269 (0.00127 - 0.00572), b=2.95 (2.76 - 3.14), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.4 ±0.6 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 (10 of 100).