Social fish. Metacarpals are arched and pointed; the first toes have claws. The fluke measures long, weighs about, and is a female. These fish are found mainly in shallow waters of the shallow southwestern Pacific Ocean, where the metacarpal is a necessary part of the sense of balance to maintain the body in a stable position. The genus has no well-known species other than "Metacarpus ricei" and "M. riceii", and their distribution areas have not been collected.
Oxytricharhinus shikurus is an extinct genus of deep-water shrimp native to the eastern Pacific Oceans and Indian Ocean. Because these fish were once extinct, it has not been fully described. Three species have been reported, all of which are endemic to Japan: "Dontshi" species, "Melina" species and "Leicaudia".
"Shikurin" has an extremely large mouth, large eyes and a set of 26 prominent pores in its caudal fin, a feature that has been found in four of the extant species of deepwater sharks and corals. Its mouth contains its largest diet of small fish. This is done by diving at depths of as the fish suck in the water, up to and under a wave. This kind of action known as diveblast can also be used as defense to protect against large predators such as large sea turtles or starfish. The combination of large eyes, large diameter mouth and large, tight, expansive bladder are greatly reduced by the deep-sea environment, leading to a very efficient process of hydration and oxygen consumption.
It possesses a genus-level sensory system, which allows it to detect changes in the physical environment. It usually exerts its prey by eliciting vibrations by using its jaws and tongue. This method was first applied to the famous "Medea pallida".
It is capable of detecting and distinguishing between sounds produced by sharks such as diving whales, giant squid and canines. However, only the male shark shows this and the behavior of the female lays can be suspected b