Myxini (pirålar) (hagfishes)
(Hagfishes) > Myxinidae
(Hagfishes) > Eptatretinae
Etymology: Eptatretus: hepta (Gr.), seven; tretos (Gr.), perforated (i.e., with holes), referring to seven gill apertures on what would later be described as Homea banksii (=E. cirrhatus) [range within genus is 6-14 pairs of gill apertures]. (See ETYFish); nelsoni: In honor of ichthyologist Gareth J. Nelson (b. 1937), then with the American Museum of Natural History, for contributions to the promotion of phylogenetic systematics. (See ETYFish).
Environment: milieu / climate zone / depth range / distribution range
; marina bottenlevande; ej vandrande; djupintervall 50 - 250 m (Ref. 51420). Subtropical
Northwest Pacific: southwest Taiwan.
Length at first maturity / Size / Vikt / Age
Maturity: Lm 24.0, range 22 - 26 cm
Max length : 25.9 cm TL hane/ej könsbestämd; (Ref. 51420)
Morfologi | Morfometri
Gill apertures usually 5 (4-6). Slime pores: prebranchial 14-20; branchial 0; trunk 35-39; tail 6-10; total 57-67. Gill apertures nonlinear and crowded.
A dwarf species; males develop testes at about 20 cm and a 22.4 cm female had elongated eggs; a 26.8 cm specimen had eggs 2.4 cm long; and a 24.4 cm specimen had 11 eggs about 1.5 cm long with polar caps already forming (Ref. 51420).
Life cycle and mating behavior
Könsmognad | Reproduktion | Lek | Ägg | Fecundity | Larver
Copulatory organ absent. The gonads of hagfishes are situated in the peritoneal cavity. The ovary is found in the anterior portion of the gonad, and the testis is found in the posterior part. The animal becomes female if the cranial part of the gonad develops or male if the caudal part undergoes differentiation. If none develops, then the animal becomes sterile. If both anterior and posterior parts develop, then the animal becomes a functional hermaphrodite. However, hermaphroditism being characterised as functional needs to be validated by more reproduction studies (Ref. 51361 ).
Fernholm, B., 1998. Hagfish systematics. p. 33-44. In J.M. Jørgensen, J.P. Lomholt, R.E. Weber and H. Malte (eds.) The biology of hagfishes. Chapman & Hall, London. 578 p. (Ref. 31276)
IUCN Red List Status (Ref. 125652)
Threat to humans
MedarbetareBilderStamps, Coins Misc.LjudCiguateraHastighetSimsättGälytaOtolithsHjärnstorlekSyn
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00200 (0.00093 - 0.00430), b=2.93 (2.74 - 3.12), in cm total length, based on LWR estimates for this Subfamily-BS (Ref. 93245
Trofisk nivå (Ref. 69278
): 4.0 ±0.5 se; based on size and trophs of closest relatives
Resiliens (Ref. 120179
): Låg, lägsta populationsfördubblingstid 4,5-14 år (Fec assumed to be <100).
Fishing Vulnerability (Ref. 59153
): Low vulnerability (16 of 100) .
Climate Vulnerability (Ref. 125649
): (0 of 100) .