It has been a while since I last posted here. Over the last
few months I have been thinking of starting up again so here I am. I found
doing a creature every week to be too much like work so now I am going to be
doing it once a month so I enjoy it.
Since I am bringing back to life my dead blog I may as well
follow suit with that theme so I present to you the Coelacanth (pronounced
see-la-canth). The Coelacanth which is nicknamed “The Living Dinosaur” or
“Living Fossil” is an ancient fish that was thought to be extinct since the end
of the Cretaceous period (66 million years ago) but on December 22, 1938 it was
discovered by museum curator Marjorie Courtenay-Latimer among the catch of the
angler Captain Hendrick Goosen. The captain was angling off the Chalumna River
on the east coast of Africa. This fish is the best example of a Lazarus Taxon
which is a species thought to extinct for one or more periods of time only to
be reappear much later. Maybe the Tasmanian Tiger or the Dodo bird or maybe even
the Pinta Island Tortoise (Lonesome George) could someday become a Lazarus
Taxon.
The Coelacanth is basically an ancient fish, mostly
unchanged for millions of years. Since it was first discovered there have only
been two species found; the first one being the West Indian Ocean Coelacanth
that Marjorie found and the other being the Indonesian Coelacanth. The
Indonesian Coelacanth was discovered on September 18, 1997 by a couple named Arnaz
and Mark Erdmann on their honeymoon at a local market in Indonesia. Mark
thought it was West Indian Ocean Coelacanth but it was brown instead of blue.
An expert saw the pictures and identified it as a separate species. It just
goes to show that because humans cannot find a species, it does not mean it is necessarily
extinct.
The Coelacanth is a lobe-finned fish which is related to a
lot of its characteristics. They are large, fat fish covered in cosmoid scales
which act as amour. Cosmoid scales have four layers, with the first being dense
bone, next being spongy bone, then one of dentine and then one of enamel. They
have eight fins: two dorsal, two pectoral, two pelvic, one anal and one caudal
fin. They can maneuver very efficiently because of this, they have been seen
doing headstands and swimming belly up. They seem to like showing off. They generally
do not swim much though, they prefer to drift with swells up and down in the
water. They are usually about 1.8 meters (5 feet) long and weigh around 60kg
(132lb) so they are heavy suckers! As you can see it does look like a
prehistoric fish.
The cool thing about this fish is that it a close cousin of
the lungfish meaning that it does have lungs. They have a “fatty lung” or a
fat-filled single-lobed vestigial lung, similar to other fish’s swim bladder.
So the coelacanth uses their lung like a swim bladder rather than breathing;
they use their gills to breathe so that means the lung cannot breathe air.
Since they tend to live in deep sea they have evolved to see
better in poor light environment. Theirs eyes are adapted to seeing low
wavelengths and it has evolved to see blue better than any other colour. To
hear it has a basilar papilla which is the same thing lizards use to hear so it
feels vibrations rather than actually hearing anything the way you and I do. The
coelacanth is the only fish alive today with ears like this. Hearing vibrations
is better as sound does not travel well in water but vibrations carry just
fine.
Animal Crossing for Wii |
Evo for Super Nintendo - Coelacanth is the purple fish on the right. |
See you next month.