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a large library of reviewed shark books, a constantly outdated shark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 that contains pictures on other marine
organisms and on marine habitats. This expansion of Elasmodiver is
in its first stages but will eventually include pages on everything
from sea stars to nudibranches. Creating this portal will take time
and for now it consists of a token offering of fish pictures. 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.
