Mastacembelus simbi Vreven & Stiassny, 2009

Family:  Mastacembelidae (Spiny eels)
Max. size:  7.79 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  Africa: lower Congo River (Ref. 84205) and the lower reaches of the Middle Congo River, just upstream of Pool Malebo (Ref. 104438).
Diagnosis:  Dorsal spines (total): 23-26; Dorsal soft rays (total): 47-55; Anal spines: 2-2; Anal 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).
Biology:  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).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless


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