【larger eye】ambient sunlight【smaller eye】bioluminescence



引用元:「クラゲイカ」左眼だけ特に大きい 発光器があるイカ カウンターシェーディング対策 | 【QMA復習】わかればいいのに https://seethefun.net/%e7%90%86%e7%b3%bb%e5%ad%a6%e5%95%8f/3400/

Histioteuthis is a genus of squid and the only member of the Histioteuthidae family. It goes by the common name cock-eyed squid, because in all species the right eye is normal-sized, round, blue and sunken; whereas the left eye is at least twice the diameter of the right eye, tubular, yellow-green, faces upward, and bulges out of the head.

In 2017, researchers at Duke University established that Histioteuthis uses its larger eye to see ambient sunlight, and its smaller eye to detect bioluminescence from prey animals.[2]

The name is composed of the Greek histion (ἱστίον, “sail”, a large webbed membrane between six of the arms, in some species) and teuthis (“squid”).[3][4]

The genus contains bioluminescent species.[5]
引用元:Histioteuthis – Wikipedia https://en.wikipedia.org/wiki/Histioteuthis

DURHAM, N.C. — From eyes the size of basketballs to appendages that blink and glow, deep-sea dwellers have developed some strange features to help them survive their cold, dark habitat.

But with one normal eye and one giant, bulging, yellow eye, the “cockeyed” squid Histioteuthis heteropsis has perhaps the strangest visage of all.

“You can’t look at one and not wonder what’s going on with them,” said Duke University biologist Kate Thomas.

By watching cockeyed squids glide and pirouette through more than 150 undersea videos collected by the Monterey Bay Aquarium Research Institute (MBARI), Thomas has gathered the first behavioral evidence that the squids’ lopsided eyes evolved to spot two very different sources of light available in the deep sea.

These observations, combined with visual simulations, indicate that the large eye is specifically adapted for gazing upwards, searching for shadows of fellow sea creatures against the rapidly fading sunlight, while the small eye is adapted for gazing downwards, scanning deeper, darker water for flashes of bioluminescence.

“The deep sea is an amazing natural laboratory for eye design, because the kinds of eyes you need to see bioluminescence are different from the kinds of eyes you need to see the basic ambient light,” said Sönke Johnsen, professor of biology at Duke University and senior author on the study. “In the case of the Histioteuthis, this cockeyed squid, they chose one eye for each.”
引用元:Mismatched eyes help squid survive ocean’s twilight zone | EurekAlert! Science News https://www.eurekalert.org/pub_releases/2017-02/du-meh020817.php