Megamouth Shark
Megachasma pelagios
Order - Lamniformes
Family – Megachasmidae
Taxonomy:
When the first megamouth shark (M. pelagios) was captured in 1976, a new
family, genus and species were created.
While there has been much discussion of evolutionary relationships of M. pelagios to other shark families,
recent studies suggest that it is the most primitive living species within the
order Lamniformes and has independently evolved it's filter feeding
characteristics.
Charaacteristics:
The dorsal surfaces
of M. pelagios are blackish brown,
while the ventral side abruptly turns white.
However, the species has a distinctive white band on the anterior
surface of the snout. M. pelagios has approximately 50 rows of
very small and numerous teeth on each jaw, but only three rows are functional.
Size: Average males are approximately 4 meters and
average females are approximately 5 meters.
The largest M. pelagios sighted
was 5.5 meters.
Food Habits:
Because there have
been so few M. pelagios sightings,
little is known about their feeding behavior.
As their name suggests, the "megamouth shark" has a huge mouth
that extends behind the eyes. Scientists
believe that the shark swims slowly through aggregations of krill and other
small prey with its mouth open. It feeds
by jutting out its jaws and sucking in the prey. Once the prey is inside the closed mouth, the
excess water is expelled through the gill openings.
Distribution: There have only been 21 confirmed sightings
of M. pelagios but they range from
the Indian, Pacific and
Habitat: M.
pelagios most likely lives in the first 15 meters of the sea, however a
tagged individual was found to descend to 150 meters at night, returning to the
epipelagic waters during the day.
References:
http://bama.ua.edu/~clydeard/bsc376/lecture9.htm
Marine Education
Society of
http://www.mesa.edu.au/friends/seashores/e_aphroditois.html
George Parsons,
Curator of Fishes, John G. Shedd Aquarium
Personal
communication 10/3/04