Saturday, 7. February 2009, 0:29
Geosesarma krathing (Orange crab)
Text: Monika Rademacher,
Photographs: Oliver Mengedoht
Translation: Ulli Bauer
Scientific name: Geosesarma krathing
Trivial name: Orange crab
Systematics: Domain: Eucaryota, kingdom: Animalia, subkingdom: Metazoa (multiple-celled animals), Eumetazoa (true tissue), grade: Bilateria, branch: Protostomia, infrakingdom: Ecdysozoa (molting animals), phylum: Arthropoda (jointed-leg invertebrates), subphylum: Crustacea, class: Malacostraca (higher crustaceans), superorder: Eucarida, order: Decapoda (ten-legged crayfish), suborder: Pleocyemata, infraorder: Reptantia, section: Brachyura (true crabs), superfamily: Grapsoidea, family: Sesarmidae (mangrove crabs), genus: Geosesarma, species: Geosesarma krathing
Origin/Range: Thailand (South-East Asia)
[attachment=8506]
Orange crab.
More pix: http://www.panzerwelten.de/v/Geosesarma/...htId=66576
Description: dark, brown carapace, (lower/back) half of the carapace blueish in color, claws orange, legs orange-brown-red to brown, eyes green, eyestalks orange.
Sex differences: Typical for crabs, the males have a narrow apron, the females have a wider apron nearly covering the entire abdomen. Moreover, females of this species seem to be of a more subdued color.
[attachment=8507]
Two females.
Size: up to 1.5 cm wide carapace
Life span: ? (two to four years)
Water temperature: tropical (about 20 to 28 °C, more activity from 24 °C upwards)
[attachment=8508]
Carapace of a G. krathing.
Tank size/stock: From 40 cm length on for a pair, keeping a small group is preferrable, however, in a tank from 60 cm upwards. If possible more females than males, but also a stock of equal numbers of males and females ought to work out fine if the tank is well-structured.
Tank set-up: Terrarium with a sufficiently big water bowl or a small built-in water part; well-structured with various levels to climb on, hideouts and substrate suitable for burrowing; plants (also weeping ones), mosses.
[attachment=8509]
Example for a suitable terrarium with water bowl.
Food: Typical for crabs, they are omnivores.
• Leaves (the main staple of many crabs in nature; mostly oak and beech are fed, however, all European broadleaved tree leaves are possible, also Indian almond leaves), muck, water plants
• Vegetables/fruit: nearly all vegetables and fruit are suitable (peas, lettuce, cucumber, apple, zucchini, pear, banana, grapes, tomato, Brussels sprouts, bell peppers) except for parsley and beans or other kinds that contain Prussic acid or copper; carrots (boiled); potato and rice (boiled) or noodles (uncooked? Don't leave these in the tank for too long a time though, they can be the cause of turbid water and finally lead to a bacteria bloom and oxygen depletion); no citrus fruit due to their high acid content
• Dry food: Catfish tabs, fish (flake) food, food pellets, rabbit, guinea pig and chinchilla food pellets (without copper!), Spirulina tabs, crayfish tabs, Gammarus
• Frozen food: Black, glass and blood worms, Cyclops, brine shrimp, clam meat
• Live food: Earthworms (it's best to cut them into pieces though, or else these worms might burrow in the substrate, possibly also under water, die and rot there unnoticed until it's too late)
• Meat (rarely): Chicken bones with meat rests (rinsed well to prevent too much fat from getting into the terrarium)
• Fish: deep-frozen smelts et.al., tuna fish, sardines, herring etc. fresh or from a can (in their own juice, not in oil)
• Calcium: cuttlebone, smashed eggshells or powdered calcium in self-made food sticks
Behavior: Relatively peaceful, their requirements on keeping conditions vary strongly: There are some crabs exclusively living on the land parts, others, however, are in the water most of the time or sit on elevated spots with direct water contact.
[attachment=8510]
Two males.
Reproduction: Specialized reproduction in fresh water with fully developed young crabs instead of larvae. The females carry relatively large eggs (> 1mm). Young crabs seem to need a real water part for developing successfully! When berried the females mostly prefer staying in their burrows and caves.
[attachment=8518]
Female - males have a narrower apron in comparison.
Socialization: Shrimp, snails (smaller specimens might be eaten).
[attachment=8519]
Molt (Ecdysis): the shed skin, or rather, the old, empty carapace of a G. krathing.
Additional information:
• Discovered and described in 1992 by Ng and Naiyanetr.
• Of two females given to us, one has survived for a nearly a year now and molted at least once.
• G. krathing has been described as tree-climbing crab when it was first discovered. Habitat: Near a river, smaller crabs were found directly at the river (this corresponds with up-to-now experience and reports according to which young Geosesarma of several species need water, whereas the adult crabs are more terrestrial or can even drown {G. nemesis}).
• In nature, up to seven crabs per square meter have been found.
• Specialized development, the mother crab carries its offspring under its abdomen for some time. Mating time is between January and April, there's an average of 50 eggs.
• Sexual maturity starting at about 1 cm carapace width.
• Researchers found out their stomach content is 77 % top soil, 13 % wood, 6 % leaves, 3 % roots and 1 % insect wings and legs as well as flowers.
[attachment=8520]
Burrow of an orange crab.
[attachment=8521]
Entire burrow system of an orange crab.
An interesting fact about Geosesarma krathing is that this crab species is quite secretive.
Text: Monika Rademacher,
Photographs: Oliver Mengedoht
Translation: Ulli Bauer
Scientific name: Geosesarma krathing
Trivial name: Orange crab
Systematics: Domain: Eucaryota, kingdom: Animalia, subkingdom: Metazoa (multiple-celled animals), Eumetazoa (true tissue), grade: Bilateria, branch: Protostomia, infrakingdom: Ecdysozoa (molting animals), phylum: Arthropoda (jointed-leg invertebrates), subphylum: Crustacea, class: Malacostraca (higher crustaceans), superorder: Eucarida, order: Decapoda (ten-legged crayfish), suborder: Pleocyemata, infraorder: Reptantia, section: Brachyura (true crabs), superfamily: Grapsoidea, family: Sesarmidae (mangrove crabs), genus: Geosesarma, species: Geosesarma krathing
Origin/Range: Thailand (South-East Asia)
[attachment=8506]
Orange crab.
More pix: http://www.panzerwelten.de/v/Geosesarma/...htId=66576
Description: dark, brown carapace, (lower/back) half of the carapace blueish in color, claws orange, legs orange-brown-red to brown, eyes green, eyestalks orange.
Sex differences: Typical for crabs, the males have a narrow apron, the females have a wider apron nearly covering the entire abdomen. Moreover, females of this species seem to be of a more subdued color.
[attachment=8507]
Two females.
Size: up to 1.5 cm wide carapace
Life span: ? (two to four years)
Water temperature: tropical (about 20 to 28 °C, more activity from 24 °C upwards)
[attachment=8508]
Carapace of a G. krathing.
Tank size/stock: From 40 cm length on for a pair, keeping a small group is preferrable, however, in a tank from 60 cm upwards. If possible more females than males, but also a stock of equal numbers of males and females ought to work out fine if the tank is well-structured.
Tank set-up: Terrarium with a sufficiently big water bowl or a small built-in water part; well-structured with various levels to climb on, hideouts and substrate suitable for burrowing; plants (also weeping ones), mosses.
[attachment=8509]
Example for a suitable terrarium with water bowl.
Food: Typical for crabs, they are omnivores.
• Leaves (the main staple of many crabs in nature; mostly oak and beech are fed, however, all European broadleaved tree leaves are possible, also Indian almond leaves), muck, water plants
• Vegetables/fruit: nearly all vegetables and fruit are suitable (peas, lettuce, cucumber, apple, zucchini, pear, banana, grapes, tomato, Brussels sprouts, bell peppers) except for parsley and beans or other kinds that contain Prussic acid or copper; carrots (boiled); potato and rice (boiled) or noodles (uncooked? Don't leave these in the tank for too long a time though, they can be the cause of turbid water and finally lead to a bacteria bloom and oxygen depletion); no citrus fruit due to their high acid content
• Dry food: Catfish tabs, fish (flake) food, food pellets, rabbit, guinea pig and chinchilla food pellets (without copper!), Spirulina tabs, crayfish tabs, Gammarus
• Frozen food: Black, glass and blood worms, Cyclops, brine shrimp, clam meat
• Live food: Earthworms (it's best to cut them into pieces though, or else these worms might burrow in the substrate, possibly also under water, die and rot there unnoticed until it's too late)
• Meat (rarely): Chicken bones with meat rests (rinsed well to prevent too much fat from getting into the terrarium)
• Fish: deep-frozen smelts et.al., tuna fish, sardines, herring etc. fresh or from a can (in their own juice, not in oil)
• Calcium: cuttlebone, smashed eggshells or powdered calcium in self-made food sticks
Behavior: Relatively peaceful, their requirements on keeping conditions vary strongly: There are some crabs exclusively living on the land parts, others, however, are in the water most of the time or sit on elevated spots with direct water contact.
[attachment=8510]
Two males.
Reproduction: Specialized reproduction in fresh water with fully developed young crabs instead of larvae. The females carry relatively large eggs (> 1mm). Young crabs seem to need a real water part for developing successfully! When berried the females mostly prefer staying in their burrows and caves.
[attachment=8518]
Female - males have a narrower apron in comparison.
Socialization: Shrimp, snails (smaller specimens might be eaten).
[attachment=8519]
Molt (Ecdysis): the shed skin, or rather, the old, empty carapace of a G. krathing.
Additional information:
• Discovered and described in 1992 by Ng and Naiyanetr.
• Of two females given to us, one has survived for a nearly a year now and molted at least once.
• G. krathing has been described as tree-climbing crab when it was first discovered. Habitat: Near a river, smaller crabs were found directly at the river (this corresponds with up-to-now experience and reports according to which young Geosesarma of several species need water, whereas the adult crabs are more terrestrial or can even drown {G. nemesis}).
• In nature, up to seven crabs per square meter have been found.
• Specialized development, the mother crab carries its offspring under its abdomen for some time. Mating time is between January and April, there's an average of 50 eggs.
• Sexual maturity starting at about 1 cm carapace width.
• Researchers found out their stomach content is 77 % top soil, 13 % wood, 6 % leaves, 3 % roots and 1 % insect wings and legs as well as flowers.
[attachment=8520]
Burrow of an orange crab.
[attachment=8521]
Entire burrow system of an orange crab.
An interesting fact about Geosesarma krathing is that this crab species is quite secretive.