was seen in the Balabac Strait under the name Sesarma obesum. Serene listed this species under the genus Chiromantes, but he was doubtful about his classification and advised that hey should be counted to the genus Metasesarma. Meanwhile, the type specimen (holotype) got lost. Ng & Schubart compared specimens of Metasesarma rousseauxi from an island northof Sabah, which figured significantly in Dana’s work. After comparing the specimens, they came to the conclusion that they were all one species. Therefore, the species that was originally described as M. rousseauxi was actually a synonym of Sesarma obesum. A male collected in 2000 was fixed as the new type specimen of the species Sesarma obesum, and the species was ultimately moved into the genus Metasesarma. Since they are widespread in the Indo-Pacific region, the possibility exists that there are multiple species, but this has not been determined yet.
M. obesum were found in Thailand’s Khao Lak-Lam Ru
National Park, on a small sandy beach along a creek
that borders the rainforest.
Martin Kanzler
Keeping Marble Crabs
At home you can keep three to five
marble crabs (one male and two to
four females) in a tall tank at least 40
cm ( 15 inches) high. Two males will
grapple each other and the weaker
crab will try to avoid the dominant
one. A layer of sand, some leaves,
roots, and pieces of wood to serve as
hiding places, as well as two dishes
In captivity, marble crabs should be provided a humid environment,
plenty of hiding places, and access to both fresh and salt water.
of water—one with fresh water and
one with sea water—will complete
the setup. Temperatures between 20°
to 28°C ( 68° to 82°F) are suitable,
and I spray some water once a day to
increase the humidity.
The crabs can be seen during the day
as they stroll around looking for food,
but they are a little shy and will run
quickly to shelter if your movements
attract their attention. They eat all
kinds of fish foods, such as different
kinds of flakes and sticks, or thawed
frozen fish foods, as well as vegetables
or fruits. They prefer carnivorous food
and will take pieces of worms or
crickets. If you keep the crabs in open
tanks they will try to climb out, so
cover the tank completely. The crabs
will molt on land.
The breeding of marble crabs is not
easy when compared to the breeding
of Geosesarma species of crabs. Female
marble crabs produce many small eggs
from which small larvae hatch. In
nature the marble females, like many
other land crabs, go to the shore to
release their fry into the sea. If you
have a saltwater tank, you can try
to raise the crab fry using methods
described for some mangrove or
saltwater crabs.
Marble crabs are easy to keep and are
very nice-looking crustaceans. If you
are crazy for crayfish or crabs, these
animals will be a good alternative or
addition to hermit crabs. D
88
www.tfhmagazine.com
October 2010
