Halicarcinus lacustris

[Kevin]

Sorry if this is the wrong section. Does anyone keep these Crabs? I understand they are freshwater, are the young also born in freshwater, or do they just live in it for most of their lives?

I guess they would need a cool-water aquarium? I arent able to get any at the moment, they are just a species im interested in.

[Ollie Mengedoht]

Hi Kevin,

sorry, see this thread now. Genus Halicarcinus belongs to the Super Familiy Majoidea – that is sewater crabs. They need a seawater tank and are of course NOT of the specialized type e.g. they reproduce with several larval stages in sea water.

[Kevin]

thanks for the reply, strange how they call them freshwater crabs then, I had thought maybe they werent, since theres also a "freshwater" shrimp found there that I know is actually a brackish/marine species.

[Ollie Mengedoht]

Hola

Probably the name is completely wrong or a mispelling. Don't You have a picture?

[Kevin]

sometimes wikipedia links doesnt work, so this is some info from the site

wikipedia
The freshwater spider crab, Halicarcinus lacustris, is a spider crab of the family Hymenosomatidae found in lakes and slow-flowing streams and rivers in south east Australia including the Norfolk Islands, and New Zealand. It is the only species of freshwater crab in New Zealand. It grows to around 10 mm in shell width.

Unlike marine crabs, the young hatch directly from the eggs carried under the folded tail of their mothers, as with freshwater crayfish. They are detritivores, feeding on both animal and vegetable material found in the organic silt of their habitat. Freshwater spider crabs have small pincers, not very effective as protection against predators like eels and other fish, causing them to spend daylight hours in crevices in fallen logs and under rocks. Their eyes are not very effective in bright sunlight, and they prefer shaded areas

It doesnt mention if the young are fully formed crabs, or zoea though, so I wasnt sure, it seemed a very interesting species.

I also found this, someone in New Zealand had found them,

http://www.fnzas.org.nz/fishroom/native-...29120.html

I sometimes get Velvet Worms, Large Earwigs, and Leif Veined Slugs that are native to New Zealand, so the possibility may be there for me to get this species eventually.

[Ollie Mengedoht]

Gosh, You're really right! I don'T believe it: Hymenosomatidae is a family of crabs with some 110 described species in nearly 20 genera and ALL of 'em are marine crabs – except for H. lacustris. This is according to scientific documents and studies really a true fresh water crab, I've never heard of anything like that.

Some useful informations are here:
• http://www.waitakere.govt.nz/Abtcit/ei/E...rcinus.asp
• http://www.publish.csiro.au/paper/MF9690163.htm
• http://www.nzetc.org/tm/scholarly/tei-Bi...dy-d4.html (incl. description key)

[Kevin]

thats amazing that its the only species within its family that is freshwater then, hopefully I am able to get these eventually.