Not just Shark
Pictures: Elasmodiver contains photos of sharks, skates, rays, and
chimaera's from around the world. It began as a simple web based
field guide to help divers find the best places to encounter
different species of sharks and rays but it has slowly evolved into
a much larger project containing information on all aspects of shark
diving and photography. There are now more than a thousand shark
pictures and sections on shark evolution, biology, and
conservation. There is a large library of reviewed shark books, a
constantly outdated shark taxonomy page, a monster list of shark
links, and deeper in the site there are numerous articles and
stories about shark encounters. Elasmodiver is now so difficult to
check for updates, that new information and pictures are listed on
an Elasmodiver Updates Page that can be accessed here:
If you're looking
for a broader range of marine life pictures the following links
represent a new area of elasmodiver.com that contains pictures of
other marine organisms and of marine habitats. This expansion of
Elasmodiver is in its first stages but will eventually include pages
on all types of marine mammals, bony fishes and marine invertebrates
as well as coastal habitats, reefscapes and other imagess relating
to the ocean. Please return regularly to enjoy the progress.
Common Names:
Coffin ray, Australian numb ray, Crampfish, Shorttailed electric ray.
Latin Name:
Hypnos monopterygium.
Family:
Hypnidae.
Identification:
Pair shaped body. Tail vestigial but with two
prominent upper lobes. Dorsum pale tan to brown, sometimes blotchy. Ventrum pale. Body appears flabby.
Spiracles small and with a pale fringe.
Size:
Maximum length 69cm.
Habitat:
Intertidal to 240m on sand, mud, and grass
flats sometimes around coral or rocky reefs.
Distribution:
Australian waters from Queensland to Western
Australia via south coast.
Behavior:
Nocturnal. Lays motionless under sand with only
spiracles protruding during the day. Main diet consists of bony fishes with
mollusks, crustaceans, and worms also being consumed. A week swimmer that
appears to flutter jerkily forward. The Coffin ray is capable of
producing an intense electric shock in the range of 200 volts that is used for
stunning prey and as an anti-predation tactic.
Reproduction:
Ovoviviparous.
Observations:
After following this ray for some time and repeatedly photographing it at
close range it was still reluctant to use its electric stunning ability. Instead
it slowly made its way to covered ground.
Photographs:
Exmouth Navy Jetty, Western Australia.
Similar species:
Some icthiologists recognised a similar
species, Hypnos subnigrum.
Reaction to divers:
Easily approached. moves away only when closely
disturbed. May shock if handled. Divers have reported severe shocks after
accidentally resting on this ray.
Diving logistics:
Two Coffin rays were spotted on a single night dive at Exmouth Navy Jetty
in W.A. This is a great dive with many sharks and rays always in residence.
Bookings can be made solely with Exmouth Dive Centre.
Other diving locations submitted by readers:
Further Reading:
Sharks and Rays of Australia - Kelvin Aitken
Reef Sharks and Rays of the World
- Scott W. Michael.
