|
|
FAQs about Marine Crab Identification 8
Related Articles:
Crabs,
Hermit Crabs, Related FAQs:
SW Crab Identification 1, SW Crab ID
2, SW Crab ID 3,
SW Crab ID 4, SW Crab ID 6,
Marine Invertebrate identification, Marine
Crabs 1,
Marine Crabs 2, Marine Crabs 3,
Marine Crabs 4, SW Crab ID 5,
SW Crab ID 6, SW Crab ID 7,
SW Crab ID 9,
Marine Crab ID 10,
Marine Crab ID 11,
Marine Crab ID 12, & Crab Behavior,
Marine Crab Selection,
Marine Crab Compatibility,
Marine Crab Systems,
Marine Crab Feeding,
Marine Crab Reproduction,
Marine Crab Disease,
Micro-Crustaceans, Amphipods,
Copepods, Mysids,
Hermit Crabs,
Shrimps,
Cleaner Shrimps,
Banded Coral Shrimp,
Mantis Shrimp,
Anemone Eating Shrimp, Crustacean
Identification, Crustacean Selection,
Crustacean Behavior, Crustacean
Compatibility, Crustacean Systems,
Crustacean Feeding, Crustacean
Disease, Crustacean Reproduction, | 
|
Please help identify this crab: Ocypodid - 11/30/07
Hello,
<Hi there.> can you please help identify this crab for us. <Will
sure try!> We got this crab from our LFS and have researched it on
your site, but could not find any information about this crab. In
one of the pictures you can see that he raises his eyes.
<Yes, I
see.>
Any information would be great.
<Unfortunately, I
can’t Id it to species level, but I can narrow it down a bit. I
believe what you have is likely an Ocypodid (family Ocypodidae).
This family includes intertidal/shore crabs, commonly called fiddler
crabs, and ghost crabs. The first clue is that set of extraordinary
eyes. Crabs with long eyestalks like that are generally
intertidal/shore crabs. Although there are many families that
contain such crabs, yours seems to fit Ocypodidae best. There are
several genera under this family, and more subgenera, so identifying
it further gets a little tricky. I tend to think that it's in the
genus Uca (fiddler crabs), as opposed to Ocypode, mainly because of
the slender eyestalks - but I could be off. Your crab doesn't have
the characteristic oversized chelae/claw typical of a fiddler, but
it could be a female or just too young to have developed one. Again,
this is all speculation. I'm sorry I can't be more specific! Please
see this link for basic morphology/comparison re:
http://www.fiddlercrab.info/uca_morphology.html
You’re probably
wondering at this point, just how suitable this crab is for your
tank. Unfortunately, not knowing your situation, I can only
speculate. Shore/intertidal crabs spend time above/below water. Some
come out at night, or when the tide's out. Some live on the
beach/mudflats in burrows. If in fact, you have a reef tank, I can’t
imagine a crab such as this doing too well long term, but I could be
wrong. One last thing of note is that crabs, in general, tend to be
opportunistic and may decide to prey on/pick at any number of
organisms in your tank, so unless this is a species-specific system,
be sure to keep an eye out for any resulting damage/loss. One
thing's for sure - it's a very pretty little crab!>
Thank you
<You're very welcome -Lynn> |  
|
Crab ID please... Atergatopsis signatus, the Giant Egg crab 9/28/07
Hi Guys...
<Hi Jo, Mich here. Sorry for the delay.>
This crab
hitched in on some live rock a few months back...
<Is a very pretty
crab!>
I've been back and forth all over and I can't seem to get an
ID on him...His nippers aren't overly large, and he doesn't seem to be
doing any damage to corals or fish,
<I hope this continues to be the
case, but crabs are never to be trusted.>
I'm just curious what he is
so I know how big he will get...he started out at around 1cm across his
back and now, 6mths later he’s around 3cm across his back...
<Well,
if my ID is correct, Atergatopsis signatus, the Giant Egg crab, can
reach up to 12 cm across! That's pretty big for any aquarium. You may
need to consider a different home for this beauty. Do you have a nearby
public aquarium?>
he is the most beautiful shade of lilac and very
smooth...he spends most of his time in a deep hole in the live rock and
comes out for a feed at night when I’m feeding the tank...any ideas
??...
<I do believe your crab may be a Giant Egg crab (Atergatopsis
signatus) but is hard to tell with just one picture. You can see more
images here. Particularly look at image # 4::
http://images.google.com/imgres?imgurl=http://decapoda.free.fr/images/brachyura/Atergatopsis_signata~_TAH_928-21.jpg&imgrefurl=http://decapoda.free.fr/illustration.php%3Fn%3D5%26sp%3D85&h=559&w=752&sz=83&hl=en&start=1&um=1&tbnid=28vhb-XTRuaakM:&tbnh=105&tbnw=141&prev=/images%3Fq%3DAtergatopsis%2Bsignatus%26svnum%3D10%26um%3D1%26hl%3Den%26safe%3Doff%26client%3Dsafari%26rls%3Den%26sa%3DG
>
Cheers...
<And to you! Mich>
JO... | 
|
Crab ID 8/9/07
Found this small (9.4mm wide carapace) crab under the seaweed on Bailey
Island, ME. Don't recall seeing any with a red "V" before. Can you ID
please?
David Reed
<Looks like an unusually coloured European
shore crab, Carcinus maenas, to me. The 5-points on the either side of
the shell are indicative of that species, though not unique to it. What
is more telling is the pointed final segment on the back pair of legs;
on most of the similar crabs, these are paddles: shore crabs are more
fully adapted to terrestrial life than most other intertidal crabs. The
other "walking" crabs like Hemigrapsus have fewer than five points on
each side of the shell. Despite its name, the European shore crab has
been transported all around the world, including both coasts of the US,
so finding one in Maine isn't unusual. They're fascinating animals --
their species name, "maenas", means "mad one", a reference to their
amazing fierceness and territoriality. They are very easy to keep in
marine or brackish water aquaria, though predatory. They can survive
exposure to dry air for days, and will tolerate salinities down to
almost (but not quite) freshwater. Anyway, I could be wrong on the ID,
so perhaps Bob or someone else will chime in. Cheers, Neale.>
Re: Crab ID 8/9/07
Thanks for the quick reply!
David
<Thanks for the thanks, but we
don't actually know if I'm right! Cheers, Neale> | 
|
Crabs... and Ascidian, IDs – 08/02/07
Hey Crew.
<Hey now!
Mich here.>
It's been a long time since I last wrote (about 3 days).
<Heehee! That is a long time from this email address!>
I have some
crabs in my display about which I'm curious. Pics are attached. The
first pic is just a cool, very big sea squirt that I have--just a cool
pic, no question.
<Neat!>
The second pic is of a decorator crab
(I think Schizophrys dama).
<Likely so.>
It is small (maybe 1/4"
tall) and I think it's a really cool crab (watching him lumber about,
etc.), but I also know your general feeling about crabs. As you can see,
he has poached some polyps from my tree corals. I saw him molesting them
tonight, although they didn't seem to mind too much.
<Hopefully he's
just fragging it and not noshing on it.>
Anyway, question #1 is
whether I should get him out of the display and, if so,
<He's not
"reef safe".
whether I can put him in my 30g refugium (4-6" DSB with
4lbs live rock and Chaeto)?
<Could.>
Will it eat my pods/Chaeto?
<I'm not sure. I'm not finding much on the diet of this particular
species but most crabs are opportunistic omnivores.>
I could put him
in my 30g QT, but not much in there for him to do.
<This may be a
good option.>
Third pic is of some type of filter feeding crab that I
noticed tonight. Not a very good picture, but it definitely has sweeper
arms that it uses to filter feed and you can clearly see its filters in
the attached pic. It doesn't look like any Porcelain Crab I've ever seen
(which is the only crab I found while researching that has similar
feather-like appendages). So, question #2 is any idea what type of crab
this is?
<Is likely a Neopetrolisthes or Petrolisthes species.>
Final question (no pic) is the suitability of what I think is a Mithrax
forceps (Red-Ridged Clinging Crab). It came in on some live rock and
I've been observing it for several months. It doesn't seem to molest
anything other than the little bit of macroalgae that I had (notice past
tense) in my display.
<"Seem to molest" is likely an accurate
description... Most crabs are opportunistic omnivores.>
Muchas
gracias.
<De Nada!>
Andy
<Mich> | 
|
  |
Stone Crabs! - 7/18/07
<Hi Bridget!>
I have pulled 3 of these
guys out of my tank in the past 6 months. <Yikes!> Pet store ID'd the
last one and advised an elimination program. All research on the web
tells how tasty they are. <I’ve never had them, but I’ve heard that as
well.> That really is kinda useless. <Well, if you do indeed have the
same variety of "stone crab" that they use in the seafood industry, you
can try Googling its scientific name: Menippe mercenaria. That's the
problem with common names, though. One name can be used for many
species.>
My biggest question is, are they really all that bad?
<Well, not if you want a crab tank! If you want a reef tank with snails,
etc, in it, then yep, I'm sorry but they’re bad. Crabs in the Menippe
genus are xanthid, or mud, crabs and have a bad reputation for being
destructive in reef tanks. Also, some Xanthids are toxic, so just in
case, don't let anyone eat those crabs!>
If so what's your best
advise for removal?
<Please see this link and the post labeled
“Trapping in Displays”:
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabfaqs2.htm
>
I do know I no longer have any hermit crabs and my yellow tang has
gone missing? <Hmmmm, not good.> Now have 3 fish in the 75, 2 true
Percula's and one coral beauty.
Thank you for your time
Bridget
<You're very welcome, and good luck! -Lynn>
Re: Stone Crabs! Follow-up 7/19/07
<Hi again, Bridget! Lynn
here.>
Well I found some pictures here
http://www.okeefes.org/Crabs/crab%20photos%20and%20scans.htm and this
guy <(Pilumnus sayi)> is definitely what I have and not the stone crabs
<(Menippe mercenaria)> *Pilumnus sayi*
<Thanks! Pilumnus sayi,
sometimes called the hairy mud crab, or spineback hairy crab, has those
same robust claws as the yummy stone crabs (Menippe mercenaria) but with
lots of bristles! Unfortunately, it’s still a xanthid and potential
trouble down the road for a mixed reef tank.>
Hubby is being a grump
and not wanting to remove these guys.
<I can understand that. As
much trouble as they can cause for the other inhabitants of your tank,
they’re still neat little creatures! Why not set up a separate tank for
them? It’s a win-win!>
Myself, I'm more than concerned about the
quantity and I'm wondering if they might be reproducing or if they just
came in with the live rock.
<Almost guaranteed that they came in
with the rock. The juvenile stages of crabs have a next to nil chance of
surviving in the average tank.>
I don't see these guys. They're
professional hiders, <Yes indeed!> I'm only finding dead bodies.
<Of
snails, etc, or the crabs themselves? If it’s snails, etc, that’s not
too surprising. If it’s crab bodies, they could just be the shed shells
from when they molt.>
Which makes me more concerned about anyone else
in the tank.
<Understandable either way!>
Tank is a 75 reef
established 3 years, new live rock with oysters 6 months ago.
<Sounds
like a nice tank to me!>
Thank you for your time.
Bridget
<You’re most welcome, Bridget. I’d try to trap these guys (see previous
link on this) and set them up in a tank of their own. Good luck! -Lynn >
CRAB ID... Yum! 7/16/07
Good Morning,
<And to
you! Mich here.>
This is my first question for the Crew; however
you forum has saved me hundreds of dollars and too numerous hours
with the information posted on you website.
<Very good to hear!>
I am trying to ID a crab in my tank. He was in a deep hole in a
piece of LR and he only came out at night. He finally got too big
for the hole and I managed to get he cornered in another piece of
LR. anyway can you help ID this little critter.
<Mmm, boy I'm not
really sure I can even get this crab to the family level, my guess
would be this might be Family Cancridae and it does resemble the Red
Rock crab (Cancer antennarius) picture posted on the site... Same
family as the Dungeness Crabs. But is more of a guess than an ID.
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabs.htm
I would doubt that it is reef safe or fish friendly by the size of
the claws. Look more like the type you might eat than keep as a pet.
I would certainly house him out of the display. Perhaps the refugium
or maybe your local Red Lobster would be a more suitable home?>
Paul
<I suppose it would be just outright wrong to ask if you had
any drawn butter? Heehee! Mich> | 
|
Crab ID and Clown/Anemone Question – 07/03/07
Crew,
Sorry to
lump two different subjects in the same e-mail, but thought it would
save you some time.
I purchased 65lbs or live rock (50 lbs
Fiji/Marshall and 15lbs Florida) about 5 months ago. In the last week or
so, I noticed two crabs that hitchhiked in. My face is pressed against
the glass every night, so I'm really surprised I haven't seen these
crabs until recently (although my tank is 110g). I have attached
pictures. I'm pretty sure the first picture is of a sponge crab, genus
Schizophrys. It is pretty small and is covered with pieces of orange
sponge. The second two pictures are of the same crab. It's hard to get a
good shot of it, but it is pretty small (maybe 1/2") and relatively flat
with hairy legs. It's claws are pretty small. I've searched the web and
WWM but can't find a picture that looks like either of these crabs. My
closest guess on the second is the Schizophrys aspera.
<Appears to
be...>
Should I remove these?
<Mmm, not yet>
Currently, I
don't have much in the way of fishes or inverts. One gold banded maroon
clown, one BTA, two cleaner shrimp, a pretty good sized clean-up crew,
and a Sailfin tang in QT. I intend to stick with smallish fish (but not
tiny) and some soft corals.
When I bought my clown, he was loving
life in a BTA. Since I've had him, though, he's spent much of his life
in a hospital tank while my display went fallow for 4+ weeks. I recently
introduced him back into the tank and he shows no interest in my BTA.
<Takes time...>
My BTA is tucked under a rock at the bottom of the
tank, but definitely visible, flowing, calling out to his friend, but
the clown seems totally uninterested. I find this strange since he was
in a BTA when I purchased him. I would love for them to have a hot,
lovely relations. Do clowns find anemones by scent, sight, some
combination of the two, or none of the two?
<Good question... I
don't know... perhaps a bit of both... It is known that the fish DO
communicate with the Anemones chemically>
Are clowns fickle, or can
it take weeks or longer for the clown to settle in and accept a BTA?
<I suspect both... plus a bit autistic... have short memories...>
As
always, your thoughts are appreciated.
Andy
<Welcome. Bob Fenner> |
|
|
|
