Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Teleostei (teleosts) >
Gadiformes (Cods) >
Macrouridae (Grenadiers or rattails)
Etymology: Hymenocephalus: Named for its transparent membrane-like head covering (‘‘hymen head’’) and fragile nature of head bones (Ref. 100825).
Eponymy: William ‘Bill’ Harding Longley (1881–1937) was a Canadian-born botanist and ichthyologist who studied colours and patterns of tropical reef fish. [...] (Ref. 128868), visit book page.
More on authors: Marshall & Iwamoto.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Marine; bathypelagic; depth range 400 - 900 m (Ref. 37108). Deep-water
Western Central Atlantic: Straits of Florida, Gulf of Mexico, Caribbean Sea, and off Rio de Janeiro, Brazil.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 39.5 cm TL male/unsexed; (Ref. 115012); max. published weight: 270.90 g (Ref. 115012)
Dorsal soft rays (total): 10 - 13. This species is distinguished by the following characters: pelvic fin rays 12-14 (usually 13-14); pectoral fin rays 14-17; projecting snout, 20-25% HL; short barbel, 4-5% HL, does not reach vertical through anterior margin of orbit; moderate orbit diameter, 28-35% HL; infraorbital width 12-15% HL; moderately long preopercular supporter, with angle at rear margin, 5-6% HL; 23-28 gill rakers; ventral striae reaching to ½ to ? distance from pelvic fin bases to periproct; otolith has moderately high predorsal lobe, with colliculi separated, closely placed across collum, terminating at some distance from anterior and posterior rims of otolith; otolith length to height (OL:OH), 1.05; total colliculum length to pseudocolliculum length (TCL:PCL), 2.6-2.8 (Ref. 98298).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Cohen, D.M., A.W. Ebeling, T. Iwamoto, S.B. McDowell, N.B. Marshall, D.E. Rosen, P. Sonoda, W.H. Weed III and L.P. Woods, 1973. Fishes of the western North Atlantic. Part six. New Haven, Sears Found. Mar. Res., Yale Univ. (Ref. 37108)
IUCN Red List Status (Ref. 130435: Version 2024-2)
Threat to humans
Harmless
Human uses
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Estimates based on models
Preferred temperature (Ref.
123201): 7.1 - 13.9, mean 9.5 °C (based on 83 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00145 (0.00087 - 0.00240), b=3.21 (3.06 - 3.36), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref.
93245).
Trophic level (Ref.
69278): 3.5 ±0.4 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): Medium, minimum population doubling time 1.4 - 4.4 years (Assuming tmax>3).
Fishing Vulnerability (Ref.
59153): Low to moderate vulnerability (30 of 100).