''Eptatretus bischoffii'' is a common hagfish of the genus ''

Eptatretus ''Eptatretus'' is a large genus of hagfish. Species There are currently 49 recognized species in this genus: * ''Eptatretus aceroi'' Polanco Fernández & Fernholm, 2014 (Acero's hagfish)Polanco Fernandez, A. & Fernholm, B. (2014): A New Specie ...

''. Its maximum length is . It lives in a

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

, non-migratory, marine habitat with its depth range between 8–50 m. It can survive in only temperate zones. These organisms are found in the South Pacific, mainly,

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. It is harmless to humans. The mode of reproduction in this kind of organism is external. The copulatory organs are absent. The

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

s of hagfishes are situated in the peritoneal cavity. The

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

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. The eggs develop in the demersal areas. The shape of the eggs are elongated. The egg contains a single micropylar opening located at the animal pole. It is situated at the bottom of a micropylar cup which lies between the anchor filaments. The single filaments are long and have an anchor-shaped apical end. The number of filaments varies around 50 but is always smaller on the vegetative end. On both ends of laid eggs, the filaments are enveloped by a gel-like matrix intertwined with large

cytoskeletal The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compo ...

biopolymer Biopolymers are natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, cl ...

s (

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...

-like intermediate filaments) of possible holocrine origin.

References

{{Taxonbar, from=Q2025285 Fish of Chile Myxinidae Fish described in 1880 Endemic fauna of Chile