Barreleye Fish With Binocular Vision & a Sole!
The Doldrums science team collected this footage, likely a Winteria telescopa, according to Dr. Marcelo Melo of the Instituto Oceanográfico, Universidade de São Paulo. He says this is the first video observation for this species, family Opisthoproctidae, is extremely rare. Most of our knowledge of this curious family is based on samples collected with fishing nets, a process that typically damages delicate specimens on the way to the surface. Barreleye fish are distinctive and recognizable because of their tubular eyes. While the eyes of most fish are placed laterally, offering a more panoramic view of surroundings, tubular eyes, parallel to each other and oriented in line with the animal’s body, provide them with the ability to see the tiniest flicker of dim sunlight and bioluminescence that comes from above; this footage was filmed at 710 meters, or as deep as a megaskyscraper is tall. There is no sunlight in the deep sea, and a flicker of bioluminescence can lead you to your next meal or away from being someone else’s next snack. Binocular vision also provides animals with incredibly precise depth perception, an invaluable tool for precision hunting and evading danger. As if those eyes weren’t enough to land this fish in the Awesomely Peculiar Hall of Fame, the animal also possesses a sole, which one paper describes as a “unique vertebrate structure” that allows the animal to reflect and control bioluminescence. A light organ (located in their interstitial tract and named a rectal bulb, but let’s not get stuck on that) allows them to cast a beam of light downward while using overlapping scales to control how much light shines through. Scientists think the sole allows barrelfish to camouflage themselves and communicate amongst their peers. Dr. Melo adds that the fish uses their small mouth as a straw to capture small, gelatinous zooplankton such as siphonophores, medusae, and salps. “And we now can understand how it swims looking upwards and finds its food in the deep-sea mesopelagic environment,” he said. Read the paper here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0159762
via: Schmidt Ocean Institute
