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Characiformes (Characins) >
Distichodontidae (Distichodus)
Etymology: Eugnathichthys: Greek, eu = good + Greek, gnathos = jaw + Greek, ichthys = fish (Ref. 45335); virgatus: This species is named virgatus, from the Latin, in reference to the conspicuous midlateral band or streak forming the characteristic pigmentation patterning of the species in life and in preservation (Ref. 94471).
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic. Tropical
Africa: middle Congo River basin, in the Sangha, Lulonga, Ruki (Ref. 94471), Itimbiri and Aruwimi (Ref. 106290), in Republic of Congo and Democratic Republic of the Congo. Possibly also in the Ubangi (Ref. 94471).
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 10.6 cm SL male/unsexed; (Ref. 94471)
Short description
Identification keys | Morphology | Morphometrics
Dorsal spines (total): 0; Dorsal soft rays (total): 15 - 17; Anal spines: 0; Anal soft rays: 11 - 12; Vertebrae: 42 - 43. Diagnosis: Eugnathichthys virgatus is unique among congeners in the possession of body pigmentation dominated by a broad lateral band intersected by numerous vertical bars resulting in a midlateral, checkerboard-like pigmentation patterning both in life and in preservation (Ref. 94471). Internally it is characterized by a marked reduction in dentition on the fifth ceratobranchial elements of the pharynx; externally it differs from congeners in the possession of a reduced total number of pectoral-fin rays, 13-15 vs. 16-18 (Ref. 94471). Eugnathichthys virgatus is further readily distinguished from E. eetveldii by the possession of 66-72 pored lateral line scales from opercle to caudal flexion vs. 96-103; 10-12 scale rows between the lateral line and the dorsal-fin origin vs. 14 or 15; and 8 or 9 scale rows between the lateral line and pelvic-fin insertion vs. 10 (Ref. 94471).It differs from E. macroterolepis in the possession of 8 or 9 scale rows between the lateral line and the pelvic-fin insertion vs. 6 or 7 (Ref. 94471).
This species lives in heavily shaded, highly humic forest rivers (Ref. 94471). Gut morphology and contents suggest that the species feeds exclusively on fish fins (Ref. 94471).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Stiassny, M.L.J., J.S.S. Denton and Monsembula Iyaba R.J.C., 2013. A new ectoparasitic distichodontid of the genus Eugnathichthys (Characiformes: Citharinoidei) from the Congo basin of central Africa, with a molecular phylogeny for the genus. Zootaxa 3693(4):479-490. (Ref. 94471)
IUCN Red List Status (Ref. 130435: Version 2024-2)
Threat to humans
Harmless
Human uses
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.6250 [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): 3.0 ±0.3 se; based on size and trophs of closest relatives
Fishing Vulnerability (Ref.
59153): Low vulnerability (10 of 100).
