Creature 331: Opisthoproctidae

Fish with a transparent head

Opisthoproctidae are a weird family of fish commonly known as Barreleye fish or Spook fish.

This is probably due to the bizarre adaptations to their eyes which they need for the dark areas on the depths of the ocean in which they live. They have enormous eyes with massive lenses which usually face upward but can be rotated to face forward if they want to change their field of view. Their dome shaped head is transparent in order to refract light into their massive eyes.

Distribution:
Opisthoproctidae can be found in all the world's oceans at depths of 400-2,500m

Classification:
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Argentiniformes
Family: Opisthoproctidae

Image Links:
http://pyramidbeach.com/2010/10/20/macropinna-microstoma/

Creature 89: Dolichopteryx longipes

A fish with mirror eyes

Description:
Dolichopteryx longipes is commonly known as the brownsnout spookfish. That name alone is enough to call it bizarre, but take a look at its appearance:

Its skin is completely transparent and the rest of its body is sometimes quite translucent.
Instead of using lenses in their eyes to focus their vision on objects they use small mirrors located interior to their eyes. Apparently this is a superior method when you are trying to see the many bioluminescent organisms that live in the oceans abyss.

Despite the fact that the species was first described in 1888, it was not until 2009 that the scientific community saw its first living specimen of this bizarre creature.

Distribution:
The Brownsnout spookfish live at depths between 500 and 2500 m below the surface of the ocean. They have been found in the Pacific and Atlantic oceans.

Classification:

Kingdom: Animalia
Phylum: Chordata
Class: Acinopterygii
Order: Argentiniformes
Family: Opisthoproctidae
Genus: Dolichopteryx
Species: Dolichopteryx longipes

Image Links:
http://quantumbiologist.wordpress.com/2011/04/26/four-eyes/
http://old.richarddawkins.net/articles/3504-39-spookfish-39-has-mirrors-for-eyes