Myxine circifrons

The species Myxine circifrons belongs to the Cyclostomi superclass and the Myxini class. Within the Myxini class, this species is nested within the Myxiniforme order and Myxinidae family. Myxine circifrons belongs to the Myxininae subfamily, a sister to the Eptatretinae and to the Rubicundinae However, there is ongoing debate on the distinction between genuses within the Myxinidae family, and future research may result in taxonomic changes == Description ==

The whiteface hagfish is an eel-like fish that grows to about 47–65 cm (about 18.6-25.6 in) in length. Gonads are situated in the peritoneal cavity. Differentiating species within the Myxine genus may be difficult, because individual species look very similar to each other. They channel water through a singular nasal duct which channels water through an olfactory organ. Whiteface hagfish have a narrow, well-developed valve connected to their olfactory organs, which channels water through their bodies without the assistance of other structures. This differentiates them from some Eptatretus species, which rely on more structures for the same task. Channeling water through their olfactory organs allows them to sense their surroundings via smell. == Distribution and habitat ==

Whiteface hagfish distribution spans along the eastern edge of the Pacific Ocean basin from California to Chile. This species is found at depths of 700–1860 meters off continental slopes living in burrows on the soft benthic substrate. Whiteface hagfish do not generally migrate; Hagfish species have been observed to be endemic to localized regions their entire lives. Because of their localized distributions, much species differentiation occurs through geologic processes such as plate spreading. However, whiteface hagfish have been observed to travel from Chile to around Peru and Ecuador. == Reproduction ==

The whiteface hagfish becomes male when the posterior part of the gonads develop and female if the anterior part develops. Due to hagfishes being poorly studied as a whole, the full lifespan of any hagfish species is unknown. == Diet and feeding behavior ==

Feeding behavior specific to whiteface hagfish is poorly understood, but it could be inferred that they feed similarly to other hagfish species. Hagfish are opportunistic scavengers. They primarily feed on detritus that falls from the surface, but also likely rely on larger, more nutrient-dense vertebrate and invertebrate remains. Food is scarce in their benthic and demersal habitats, so hagfish swarm to feed when large amounts of food are present. == Predation ==

Hagfish are not commonly preyed upon because of their unusual ability to produce copious amounts of slime. Hagfish, whiteface hagfish included, excrete threads of mucins into the water, which produces an unusually thick layer of slime around its body. The unique structure of the slime produced behaves more like fibers because of its viscosity, which strongly deters predators from feeding on them. == Conservation status ==

As of 2011, whiteface hagfish have been listed as least concern. Hagfish have been utilized as a food source in East Asia for decades, leaving an impact on hagfish fisheries in Asia. This may impact east Pacific hagfish species (such as whiteface hagfish) whose previously unaffected populations could be impacted by novel human interaction. == References ==