FAQs about Marine Crab Identification
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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 Crab ID 7, Marine Crab ID 8, Marine Crab ID 9, Marine Crab ID 10, Marine Crab ID 12, SW Crab ID 13, SW Crab ID 15, SW Crab ID 16, SW Crab ID 17, SW Crab ID 18,
SW Crab ID 19,
SW Crab ID 20,
SW Crab ID 21,
SW Crab ID
22,
& Marine Invertebrate
identification, Marine
Crabs 1, Marine
Crabs 2, Marine
Crabs 3, Marine Crabs
4, & 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,
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Crab ID: Possible Liomera sp. -- 9/29/08
Hey folks,
<Hi there, Joe.>
Maybe you can help me ID this hitchhiker I got on a recent order
of coral from Tonga.
<It's a pretty little thing, isn't it?>
It is nocturnal and is currently about 3/8 inch in size (about
like a popcorn kernel). This is the best photo I can get for now
but its strange pink color should narrow the list.
<Let's hope so! It looks like something in the genus
Liomera, possibly Liomera rubra:
http://www.botany.hawaii.edu/basch/uhnpscesu/htms/kalainvr/images/crustacean/Lio-rugataK26x7.jpg
or Liomera margaritata:
http://www.conchology.be/es/availableshells/shellsforsaledetails.php?uniquenumber=425625#f >
Thanks
Joe Faszl
<You're very welcome. Take care --Lynn>
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Re: Crab ID: Possible Liomera sp. --
10/2/08
Excellent,
<Hi there, Joe!>
That looks like it.
<Yay!>
If it can find a food source I hope to keep it around for a
while.
<Sounds good. Crabs tend to be omnivorous/opportunistic
creatures, so chances are it'll be fine for quite a while.
You can also offer it meaty bits (of marine origin) and/or some
sinking food pellets. Keeping the growing crab well fed will help
discourage it from sampling some of its fellow
tank-mates!>
If it gets too big, there is always hot garlic butter ;o)
<Heeee!!>
Thanks for the information and the quick reply.
<You're very welcome, Joe.>
Joe
<Take care, -Lynn>
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Reef Aquarium Hitchhiker Crab ID Needed?
9/26/08
Hello, I wondered if you could identify this crab?
Thank you in advance~
<Mmm, I can't seem to find in my ref.s... Can you wait a
till 10/6 or so? Will ask LynnZ to look at. BobF>
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Re: Reef Aquarium Hitchhiker Crab ID Needed?
9/26/08
Alright, thank you for the help.
It has stumped me, he almost has the body of an Arrow Crab, legs of
a Hawaiian Swimming Crab of a Sally Lightfoot.
Then the claws are really interesting, it looks like one's for
veggies and one's for meat?? lol.
<An apt description! Let's see what Lynn says. Cheers,
BobF> |
Mystery crab 08/08/2008 good day from Oregon
<<Good day from sunny England. Andrew here today>> I am
new to reefs (saltwater for the truth) and have found out that you
inherit what is in the live rock . I have found around 5 brittle
star type fish 3 or 4 other types of star fish , red feather
dusters along with other brilliant thing AND one not so good guy .
on the picture attached ,the best one I could get of him , he is in
the center of the photo in the hole . has pinkish white hairy legs
dark black main body . Good guy bad guy? anyways I found the
mention of traps, I am going to try to capture it tonight . if you
could ID it . Where I got the live rocks, they says it a hairy crab
(little vague if you ask me). <<A little too hard to say /
make out from the picture you supplied. Please do look have a look
here,
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabs.htm
and related FAQ's and articles. Maybe trap the crab, put in a
plastic tub and photograph / re-submit and we shall try
again.>> James <<Thanks for the question. A
Nixon>> |
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Hitchhiker crab 07/28/2008 Hi <<Good
evening, Andrew today>> Caught this crab this morning. I knew
he was in some Live Rock last October. Amazing markings. Do you
have any idea what species he may be? <<My educated guess
would be that its a Anomuran crab, from the family Porcellanidae
family. One I would consider reef safe>> Cheers, Michael
<<Thanks for the question, A Nixon>> |
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Hitchhiker Crab -- 7/28/08 Hi, guys! <Hi
there!> I will keep it short. I found this dude in my live rock
and flushed him out by removing the rock and running fresh water
through my star polyps where he was living. <Yikes!> Do you
know what species he is? <I wish. Unfortunately, I can't see
enough detail to even narrow it to family/genus level. Suffice it
to say though, that crabs are predominantly opportunistic
omnivores, so the potential is there for it to pose a threat to
other livestock. This is particularly true as the crab grows in
size. If the crab is fairly small right now, you could either leave
it in place, monitor and trap if/when necessary, or simply find it
another home elsewhere. It's up to you.> I searched your
site and the internet and found many nice crab photos but none like
him. Thanks. <You're very welcome!>
http://www.fishpondinfo.com/photos/crustaceans/crabs/scary1.jpg
http://www.fishpondinfo.com/photos/crustaceans/crabs/scary2.jpg
http://www.fishpondinfo.com/photos/crustaceans/crabs/scary3.jpg
http://www.fishpondinfo.com/photos/crustaceans/crabs/scary4.jpg
It's ok if you don't know. <Thanks, it always frustrates
me to not be able to get an ID for someone, but crabs are
notoriously difficult in that regard. There are just so many
thousands of possibilities that it boggles the mind. Our best
chance at identifying these neat little creatures begins with
detailed/high resolution photos from above and below (including all
legs), as well as views from the front, showing the claws, eyes/eye
placement, etc, along with information such as size and where it
came from. Even then, it can be frustratingly difficult due to the
lack of readily available photos of every crab on the planet. With
that being said however, we can usually narrow things down to
family level which is at least a good start! Again, I apologize for
not being able to supply this for you. Good luck with your little
crab. :-) Take care, -Lynn> |
Re: Hitchhiker Crab, Plus Possible Poriferan -- 7/28/08
<Hello again!> Thanks so much Lynn even though you
didn't know what he was! <You're very welcome!> I
thought I was the only person on the internet who still answers
all questions and promptly! It's hard work! <Well, we do
our best, and yes, it can indeed be hard work -- but it's
well worth it!> I run a huge web site myself mostly on
freshwater aquariums and ponds. <Excellent, so you can
definitely relate, huh!> People don't realize how much
time it eats up to respond to so many questions. I thought my
photos were pretty good, in fact better than looking at him in
person since he's so tiny! <I'm sorry, they were
indeed good photos, especially for a small crab! It's just
that when it comes to identifying these critters, and especially
crabs, it's all in the details. These include
shape/texture/color of the overall carapace, whether it's
smooth or 'hairy', the number of spines/shape of the
carapace edge, eye placement/color, length of eye-stalks, how
many legs, the shape/length/color of legs and claws and whether
there are any 'teeth', spines, bumps, etc, on them, the
shape of the tips of the claws (are they pointed, blunt, or
spatulate), the depth of the body, etc, etc, and that's just
the basics. LOL The list of criteria goes on and on! The best way
to ID these guys is to have it directly in front of you so that
you can pick out all the details.> The little crab is in a 3
gallon exile tank <Good> with the Emerald Mithrax crab the
store guy told me would be great (great at picking at my star
polyps as it turned out). <Yep, that's annoying for
sure!> The crabs seem fine but haven't run in to each
other yet. <Very good. I'm so glad to hear that he's
got a good home. Many of these neat little creatures end up being
disposed of and that's a real shame.> Now, that I know
someone may be able to help in my new foray in to saltwater, I
have a few other unidentified thingamabobs in my tank. One has
appeared out of nowhere and grown really fast in under a week. In
fact, I didn't even notice it until about three days ago, and
it's doubled in size. <Yowza!> It's attached to the
live rock under my favorite hitchhiked feather duster. The base
is a little fuzzy. The stalk is pastel yellow, almost like a
crayon. It has no real mouth, arms, or legs or anything but it is
growing. I will have to get a photo. <Please do, I'd love
to see it.> It looks like it's calcareous. Today, the tip
changed in appearance to have a rectangular-shaped protrusion. It
kind of curves up at the end. I'm guessing it's either a
strange yellow algae or perhaps a fungus (are there freshwater
funguses?). <Sure, there are marine versions as well. Fungi
are everywhere. I'm thinking that what you have though could
be a Poriferan/sponge of some sort (would need to see a photo).
The neat thing about these guys is the diversity of shape and
color that they come in. It's truly amazing. For more
information/photos, please see Bob's pages regarding sponges,
starting here (3 pages): http://www.wetwebmedia.com/sponges.htm .
Be sure to check out the associated links at the top of the link
as well!> The little feather duster really doesn't like it
since it's in its space! I'm wondering if I should bust
it off. <Hmmm, well it depends. If it is indeed threatening
something you like, you could attempt to remove the offender
(although if it's a sponge, many times they simply grow
back). If you do (and in case it's a sponge), I'd remove
the rock from the tank first. I'd take it out, scrape away as
much of the offender as possible, then scrub the area with a
toothbrush, and rinse *well* with tank water (into a bucket or
similar). Also, you might want to check your nutrient
levels/nitrates. The organism's rapid growth could be an
indicator of such. In the meantime, if you can get us a photo,
we'll see if we can't narrow down/confirm what you've
got there!> Thanks again. <You bet. Take care,
-Lynn>
Update Re: Hitchhiker Crab, Plus Possible Poriferan,
Macroalgae -- 7/30/08 <Well hello again!> Ok, I threw
up some photos quickly since I'm low on time. <Appreciate
it!> Photo of the entire 12 gallon nano cube showing where the
"thing" is:
http://www.fishpondinfo.com/photos/other/other/temp1.jpg <Nice
looking system.> Photo of the thing a few days ago when it
grew fast and was yellow. My favorite little feather duster is
open to the right of it.:
http://www.fishpondinfo.com/photos/other/other/temp2.jpg
<Neat> Photo from today of it with the feather duster,
Zoanthids, xenia, macroalgae, etc. When I came home, the thing
had turned green!:
http://www.fishpondinfo.com/photos/other/other/temp3.jpg <Ah
yes, that helps. It looks like some sort of macroalgae, possibly
in the genus Halimeda (a calcareous algae). We should be able to
tell when it gets a bit farther along (if it's that or
something else). Here are some links re:
http://www.wetwebmedia.com/greenalg.htm
http://www.reefkeeping.com/issues/2004-04/nftt/index.php Good
photos here:
http://www.reefcorner.com/SpecimenSheets/halimeda.htm It
definitely likes the light. <Yep> There were no sponge
matches on the site you gave me but fan sponges seem to come the
closest. Is that what it is? <Don't think so.> The
feather duster has bent itself off to the right to avoid bumping
in to this thing that I swear wasn't there at all a week ago!
<Funny how things spring up like that isn't it! It's a
matter of conditions becoming favorable for the organism's
growth/survival.> I put in about 15 ml.s of RowaPhos weekly in a
little mesh bag to keep the phosphate low. I use RO water. It
takes over two hours to make 3 gallons once a week. <Yikes.
That sounds like an awful long time to make just 3 gal's of
RO water (is it RO only or actually RO/DI?). Here are some
contributing factors to low production: a connection/plumbing
problem, small unit, clogged/exhausted membranes, very cold
water, or low water pressure. Just for comparison, I have a
Typhoon III (75 GPD) RO/DI unit from AirWaterIce that takes about
45 min's to make 3 gallons. That's with the (tap)water
pressure at about 68-70gph. In the winter when the water is in
the fifties(F) it takes about an hour instead. I'd go through
the above list and see if anything pops.> I don't know how
those with large tanks do it; they must run the RO all the time
which I'd be afraid to do (leaks, wasting huge amounts of
water; we're on a well). <Ah, I see. Have you checked the
TDS (total dissolved solids) level of the well water? If it's
really high, you may be exhausting/clogging the membranes pretty
quickly. That would definitely slow things down.> Here are two
other photos if you can confirm what I think they are: Pineapple
sponge? http://www.fishpondinfo.com/photos/other/other/squirt.jpg
<Ding, ding, ding! You are correct. It's a
harmless/beneficial little Syconoid sponge, aka a Pineapple or
Q-tip sponge.> Sponge of some sort (the yellow thing at the
top of the rock)?
http://www.fishpondinfo.com/photos/other/other/sponge.jpg <I
can't quite tell, but yes, it could be that or one of several
other harmless organisms, like a Bryozoan.> Thanks again!
<You're very welcome! Take care, -Lynn>
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Re: Crab ID -07/18/08
<Am sending this mystery to our fave ID'er... Lynn... stay
tuned... BobF> WooHoo - fave ID'er! Thanks Bob! I actually
saw this query last night but didn't grab it because I knew I
wasn't going to be able to send a reply until later on this
afternoon or tomorrow. I've had a couple of things come up that
I need to tend to, but I'll dig in as soon as I can :-) Take
care and have a great weekend! -Lynn <Thank you Lynn... not just
being lazy... am away from ref. works! Cheers, BobF> <<LOL
Lazy is a term that I would never associate with you! I can't
imagine having your schedule - or workload! I left that query in
case someone else had the answer(s), but I'd already planned to
nab it this morning if it was still unanswered. You know I'm
always happy to take the critters! :-) Hope you have some fun plans
lined up for this weekend. We're having some friends over
tomorrow night for dinner and mucho Tequila. Wish you were in the
neighborhood! Take care, -Lynn <Ahh, tah kill yah! Very good
ones (triple distilled) are faves of many folks in the livestock
whlse. trade for some reason... The smell always seems to remind me
to roll up my sleeve... Cheers! Kanpai! Twenty three skidoo, and
pass me the aspirin. BobF>
Crab ID: Likely Xanthid --
7/18/08 Dear WWM Crew, <Hi Kevin> We bought a very small
piece of live rock...and now have two very large pain in the glass
hitchhiker crabs. They are not large...just large pains. <They
certainly can be!> I think one of them ate the arm off my
starfish...hmmm. <Oh, not nice at all.> I have included a
photo here as it seems you have had someone ask about this crab
before, but their photo was very blurry and I cannot tell.
Questions are: What type of crab is it? <Looks like a Xanthid
(Family Xanthidae) of some sort. I'm sorry I can't be more
specific.> What should we do with it? <I would find it
another home.> The second crab...is also hairy like this one but
more "spiny." However, I cannot catch him...seems like
some late nights are ahead. <Been there, done that! If/when you
do get him out of there, please do send along a photo and we'll
take a look at it. Also, if you know where the rock came from, that
would be great.> Thanks, <You're very welcome. Take care,
-Lynn> |
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Strange Crustacean: Need More Information -
7/11/08 Hi. My name's Brian, <Hi Brian, Lynn here this
afternoon.> ..and I recently went to South Padre for the second
time, <What a great place that is!> ..and once again I caught
this strange crustacean. I caught one on my first trip to SP and
spent days trying to identify it on the internet but never found
anything, and the same thing this time...I Googled "sand
flea", "sea lice", South Padre crustaceans",
but could never find what I was looking for. <Yep, that's
frustrating.> It surely can't be a new species because I saw
several of them and I can't be the only one who's come
across one. But anyways, the crustacean looked somewhat similar to
a horseshoe crab. It was about 1 inch long with a thin tail that
was a couple of inches long. It was a pale white color, had several
overlapping segments to its carapace, and I couldn't find any
eyes on it. On the bottom it had, I believe six legs, and each leg
was like a small crab pincher. Please help me identify this
creature...I really really REALLY wanna know what it is! <Me
too! In all the years I've been going to the Texas coast,
I've never seen anything quite like what you've described.
I looked around, did some research and finally asked a nice fellow
from the Natural History Museum in Los Angeles for some help.
Unfortunately, he needed more information. He said that what you
saw could be anything from a dead Mole crab with its thin abdomen
extended out behind it, to a large isopod of some sort. Here's
a link that shows a bit more regarding Mole crabs (Emerita spp.):
http://www.diatribune.com/marine-life-series-mole-crabs . The
creature also sounds a bit like a Cumacean, but I've never
heard of one that large and besides, they have more than 6 legs.
Here's a link with more information regarding Cumaceans:
http://en.wikipedia.org/wiki/Cumacea. Unfortunately, at this point,
I'd really need a good close-up photo in order to have any
chance at getting an ID for you.> I wasn't able to get a
very decent picture, the one we got is blurry, and my step-dad
isn't letting me have it for some reason. <Well Brian, the
next time you go back to Padre Island be sure to look around for
more of the little critters. You might want to see if your camera
has a 'Macro' mode/setting, usually indicated by a small
flower or daisy-like icon. In macro mode, you should be able to get
some good shots. At that time, please do send them along. I'd
love to solve this little mystery! Take care, -Lynn> |
Re: Strange Crustacean: Likely Mole Crab -
7/11/08 Hello again. <Hi Brian!> So this time I've
included a picture, it's still blurry but it was the best one
out of five, and in conjunction with my description you can see a
little better what I was talking about. <Yep, thanks for
sending that along. It makes all the difference.> I looked up
more pictures of both of your suggestions, and I think the
creature I caught was likely some kind of mole crab <I agree.
It definitely looks like a Mole or Sand crab of some sort --
something in the Superfamily Hippoidea, possibly in the Family
Albuneidae.> ..(although it wasn't dead, because it was
crawling around in my hand), the only difference was that most of
the pictures I found of mole crabs didn't have the long thin
tail I described (which you can make out in my photo).
<Interestingly enough, I've seen Mole crabs that look very
similar. The only difference is that what looks like a tail is
actually a pair of antennae on the head. Take a look at this
photo:
http://www.dnr.sc.gov/marine/sertc/images/photo%20gallery/Albunea.jpg
. At first glance, it looks like the narrower end on the right
*should* be the head, but it's not. It fools the eye a bit.
Here's another link with more information on Mole crabs in
this Family:
http://www.crustacea.net/crustace/anomura/www/albunei.htm.
They're neat looking little critters, aren't they!>
But for now, I'm going to assume that I caught a mole
crab....but let me know if you have any other opinions. <I
think we've got it!> Thanks for the help. <You're
very welcome and thanks again for sending in the photo! Take
care, -Lynn>
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