It's a rare one, this Frilled Shark.
Not specific to the waters off Japan, when it is found, however, more often than not, it is in its waters.
Known as Chlamydoselachus anguineus, the Frilled Shark when caught off Suruga Bay off Shizukoka-ken, is caught off waters between 50-200 meters (160–660 feet) deep but has been caught elsewhere as deep as 1,570 meters (5,150 feet).
Everything about this creature screams 'stunt-double' from Jurassic World!
Despite the image above, it's NOT as huge as you might expect, but if you've ever drowned worms (aka fishing), you'll know that a two meter (6.6 feet) long swimming anything is frickin' scary... those of you who have screamed when a piece of seaweed brushed your thigh know exactly what I am talking about.
The Frilled Shark has a body similar to an eel... its dorsal (top spine) fin, pelvic and anal fins are all at the back end of the body.
It gets its name from the six slits of gills, but what is striking is that the first set meets right across its throat so that it looks like a collar.
While it has long, flexible jaws like an eel (sung to the tune of That's Amore by Dean Martin: "when you're diving at night, and your feet feel the bite, that's a moray), (the eyes are forward above the jaws - like an eel and differing from a shark), one of the striking features after that huge snake-like head is its teeth.
The tooth rows are rather widely spaced, numbering 19–28 in the upper jaw and 21–29 in the lower jaw.
The teeth number around 300 in all; each tooth is small, with three slender, needle-like cusps alternating with two cusplets. These needle-like teeth are excellent for ripping apart its favorite food - cephalopods - squids and octopi.
How do they reproduce? Not sure... I don't think the actual process has been observed, but scientists do know that the female will have two to 16 eggs inside her... but the sharks hatch as embryos INSIDE her, living off the egg yolk sac still attached to the baby sharks.
The egg capsule is shed when the embryo grows to six to eight centimeters (2.4–3.1 inches) long, and is expelled from the female's body; at this time the embryo's external gills are fully developed
Gestation period can be as long as 3-1/2 YEARS, which is the longest of any vertebrate critter.
Considered to be 'Near Threatened', the Frilled Shark struggles owing to its low reproductive rate (3-1/2 years!), so anytime it gets caught up in commercial fishing catches, the species takes a hit - however, it is not commercially fished for,
I had not even heard of the Frilled Shark until Friday when my son Hudson described it to me - he reads lots of books on sharks (he also previously told me about the Goblin shark - see HERE).
So... Thank-you, Hudson.