গুীরহর (হ্যাগফিশ) (hagfishes) >
Myxiniformes (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); deani: In honor of American ichthyologist Bashford Dean (1867-1928), American Museum of Natural History, for his work on the embryology of E. stoutii. (See ETYFish).
More on authors: Evermann & Goldsborough.
Environment: milieu / climate zone / depth range / distribution range
বাস্তুসংস্থান
সামুদ্রিক ব্যথিডিমারসাল সমুদ্র তলদেশবিহারী; অ_ পরিযায়ী; গভীরতার পরিসীমা 103 - 2743 m (Ref. 31276). Deep-water; 60°N - 27°N, 148°W - 114°W
Eastern Pacific: southeastern Alaska to central Baja California, Mexico.
Length at first maturity / আকৃতি / ওজন / Age
Maturity: Lm 38.0 range ? - ? cm
Max length : 63.5 cm TL পুরুষ/ লিঙ্গ অনিধর্ারিত ; (Ref. 96339)
পৃষ্ঠীয় কাঁটা (মোট ) : 0; পৃষ্ঠীয় নরম পাখনা দন্ড (মোট ) : 0; পায়ূ কাঁটা : 0; পায়ূর নরম পাখনা্তুন্ড: 0. No true fins - one dorsal finfold, far back, median, very low, continuous with the caudal; caudal moderately broad, and round with ray-like markings; ventral finfold very low, origin somewhat posterior to last gill aperture, extending to anus (Ref. 6885). Prune colored, preserved specimens black; frequently piebald with light spots; the very edges of caudal and ventral finfolds may be light colored (Ref. 6885).
Inhabits mud bottoms (Ref. 2850). Minimum depth reported at 103 m (Ref. 80811).
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 ). In one study (Ref. 40710), hermaphroditism is exhibited by only 0.2% of the individuals examined.
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. 130435)
Threat to humans
Harmless
Human uses
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ইন্টারনেট সুত্র
Estimates based on models
Preferred temperature (Ref.
123201): 3.2 - 5.5, mean 4.3 °C (based on 54 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00234 (0.00139 - 0.00396), b=2.93 (2.78 - 3.08), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref.
93245).
ট্রফিক পর্যায়ে (Ref.
69278): 3.8 ±0.52 se; based on food items.
স্থিতিস্থাপক (Ref.
120179): নিম্ন/ , সর্বনিম্ন প্রজন দ্বিগুনের সময় ৪.৪-১৪ বৎসর (Fec = 14).
Fishing Vulnerability (Ref.
59153): Moderate to high vulnerability (45 of 100).
