Actinopteri (ray-finned fishes) > Saccopharyngiformes
(Swallowers and gulpers) > Monognathidae
Etymology: Monognathus: Greek, monos = one + Greek, gnathos = jaw (Ref. 45335); nigeli: Named after Nigel Merrett who has provided the suthors with several specimens of Monognathus and was very helpful during their revisionary work. More on authors: Bertelsen & Nielsen.
Environment: milieu / climate zone / depth range / distribution range
Marine; bathypelagic; depth range 1500 - 3910 m (Ref. 34506), usually - m (Ref. ). Deep-water; 0°C -
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 5.7 cm TL male/unsexed; (Ref. 34506)
Morphology | Morphometrics
soft rays: 56 - 60. M. nigeli differs from the other species of the genus by the following combination of characters: head long with elongate, pointed snout and almost straight jaw, skull length 6.0-7.0% TL, rostral fang strongly hooked with distal part in a neatly right angle to dorsal profile of skull, predorsal length 14.5-18.5% TL, anterior anal fin ray below dorsal fin ray nos. 15-21, and 5 lateral, subdermal spots of pigmentation (Ref. 34506).
Four "Discovery" specimens were taken in closing nets between 1510 and 3910 m depth, three of these 1500-2000 m, and one 23 m above the bottom. The "Vityaz" specimen was taken between 3000 m and the surface (Ref. 34506).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Bertelsen, E. and J.G. Nielsen, 1987. The deep sea eel family Monognathidae (Pisces, Anguilliformes). Steenstrupia, 13(4):141-198. (Ref. 34506)
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
= 0.5001 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00102 (0.00046 - 0.00225), b=3.06 (2.88 - 3.24), in cm total length, based on all LWR estimates for this body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.2 ±0.5 se; based on size and trophs of closest relatives
Vulnerability (Ref. 59153
): Low vulnerability (10 of 100) .