Jump to content

Leslie

Critter Expert
  • Content Count

    1819
  • Joined

  • Last visited

Posts posted by Leslie


  1. Hi everyone --

    Some of our members from the Caymans were able to help out Sammy De Grave in his quest to identify this shrimp. This morning he wrote me that the mystery is finally solved. It's Periclimenes harringtoni which was described in 1949. Up to now it's only been known from Bermuda & the Tortugas so this is a major range extension. Even though it's not a new species this is still a very exciting discovery because it hasn't been seen since 1951, the sponge association was unknown, and the live coloration has never been described. Sammy plans to write it up for publication. Has anyone seen it in other areas of the Caribbean?

     

    Congratulations to everyone involved!


  2. You can't see it too clearly because of the depth of field in the image, but the spines are sticking out of the fish right down the length of it's body to it's tail. Also where the spines are sticking in, the colouration of the skin around is darkened for a large area around it, perhaps indicating infection. So I assume that worm must have wrapped itself around the fish to cause so many spines to wound over such a large area.

     

    I would opt for a different scenario: the fish bit the worm, got a mouth/face full of spines with the worm still attached, and while struggling to break free of the worm's spines the fish kept hitting the worm only to get more & more spines. Someone who really knows what species the fish is will have to tell us if the color is normal or not. Infection from the spines is certainly a possibility - there's a mild toxin carried inside the spines & associated bacteria/marine viruses on the surface. Some people have gotten skin lesions after handling fireworms.


  3. Brian - It's a fish. (Sorry, couldn't resist.....) The spines are from a fireworm that Mr. Fish unwisely chose to nibble on. They'll drop off in time. As long as the fish didn't get any spines deep into it's eyes it should be fine.

     

    Tubino - For small species it is extremely hard to distinguish between introductions, range extensions, and undiscovered natives, particularly for the tropics or any other region where the fauna is poorly known. Even here on the US west coast - one of the best studied faunas anywhere - we are constantly finding new species & having difficulty determining their status. Good taxonomy is the basis for all biological sciences but the number of taxonomists just keeps declining as does the support for fundamental biodiversity surveys.


  4. It certainly is Anne. I'm terrible at bivalves & the very expensive book I bought on bivalves of southern Florida mostly shows clean dead shells.....not much of a help! Maybe this is some kind of oyster like a winged oyster or a jewelbox. There's a terrific site for shells from your area at http://jaxshells.org/ if you really want to try tracking this down.


  5. The shrimp is Heptocarpus stylus - the bright blue spots are diagnostic even though the body color may be kelp colored. It's typically found on kelp. The nudi is Adalaria proxima I think - Marli's much better at NEP nudis than I am.

     

    And I goofed on the amphipod - it's Chromopleustes oculatus. Don't know why but I have the other name stuck in my head, sorry.


  6. That would be Chromopleustes pugettensis. It's a northern counterpart to Chromopleustes lineatus - I've got a picture of it here

    http://www.flickr.com/photos/86448061@N00/370021332/ The white band on the back is bigger in C. pugettensis. Like Daniel's cyproideid these are out in the open with warning coloration. They're definitely distasteful to fish & C. pugettensis is fairly agressive - I've heard of them biting divers who try to catch them. C. lineatus is commonly found living on bat star Patira miniata. that's a lovely shot - the pod looks like an alien on its own little planet. Is that a Nereocystis its on?


  7. Here's some interesting reading on the subject --

     

     

    HERMIT CRAB - CNIDARIAN ASSOCIATIONS IN THE NORTHERN GULF OF MEXICO (SYMBIOSIS, CALLIACTIS, HYDRACTINIA).

    Creator BROOKS, WILLIAM RANDALL.

    Abstract The associations of hermit crabs with two groups of Cnidaria, sea anemones (Actiniaria) and hydroids (Hydroida), in the northern Gulf of Mexico, were studied.

    Two populations of the hermit crab, Pagurus pollicaris, were behaviorally distinct in that one population transferred significantly more anemones (Calliactis tricolor) to their gastropod shells than did the other. Both populations of P. pollicaris and one population of another hermit crab, P. impressus, transferred fewer C. tricolor after four weeks in an aquarium than they did in their first week. The chemical presence of the octopus, Octopus joubini, however, increased the number of anemone transfers by both species of hermit crab. The more active anemone-transferring population of P. pollicaris was collected from an area with a greater density of O. joubini than the area of the less-active population. Therefore, the differences between the two populations of P. pollicaris may have been due in part to differences in predation pressure (i.e., by O. joubini or other predators).

    The shell entry and shell selection of two populations each of P. pollicaris, P. longicarpus, and Clibanarius vittatus, for hydroidcolonized (either Hydractinia echinata or Podocoryne selena) shells was observed under various conditions. All three species either initially chose or subsequently switched into bare shells, even in the presence of a predator. The population of P. pollicaris where O. joubini was more abundant selected hydroid-colonized shells more frequently in one experiment than did the other population of crabs.

    The hydroid-colonized shell was a deterrent to predation by the stone crab, Menippe mercenaria, and O. joubini. Predation by the calico crab, Hepatus epheliticus, was not deterred by a hydroid colony on the shell inhabited by P. pollicaris.

    The anemone, C. tricolor, and the hydroids rarely co-occur on the same gastropod shell. Contact and subsequent cnida discharge by the anemone and the hydroids significantly contribute to their negative association.

    Previously, it was unknown how C. tricolor reproduced. The present study reports the discovery of a C. tricolor anemone that was undergoing longitudinal fission.

     

    Thesis (Ph.D.)--The Florida State University, 1984.


  8. Hi Kay - I agree with Will in that the "anemones" which are attached just under the rim of the shell are probably hydroids. Are those other cnidarians on the right also attached? There are many cnidarians which are specialized hermit-crab associates, and some of them will only associate with one species of hermit. It's also common for a crab to carry 2 or more species - one on the outside of the shell, one just under the rim, and sometimes one species tucked deep inside the shell which feeds on the crab's feces. Yuck! And then there are hydroid species like Hydractinia echinata which completely cover the outside of the shell.


  9. I've been wondering about this one too. It's the most photographed Indo-Pacific amphipod (by the way, where did you see it?) and I have never found a name for it beyond family Cyproideidae. Most amphipods either live hidden away or have cryptic coloration so that they blend into their surroundings to avoid predation. This one though seems to live out in the open. That suggests that the color pattern is a warning that the bug tastes nasty or might even be poisonous. If you don't mind I'll send off your photo to a friend who specializes in amphipods & see if he can put a name on it.


  10. Methinks it may be a wormie (eww!) thing...Marli

     

    "Eww!" Et tu, Marli? :)

     

    But you're right, I do think it's a wormie thing. Take a look at Art's picture of a terebellid polychaete http://www.flickr.com/photos/80125969@N00/374980417/ Pigmentation on the feeding tentacles & the body are very similar to Jose's critter. Terebellids can swim. Sometimes they are swept up into the water column involuntarily or swim up to escape predators. Occasionally the pelagic larvae don't settle on the bottom; instead they continue to develop & live in the water. A fellow worm-lover visiting the museum & I are working on terebellids right now. We both think Jose's critter is one. GOOD CAPTURE, JOSE!!! ;)


  11. That one gets posted here every so often. It's not a true shrimp. This belongs with mud shrimps & ghost shrimps in the order Thalassinidea. It appears to be in the genus Corallianassa. These are farmerrs - they capture floating bits of seagrass & other vegetation & store them down in their burrows. Once the seagrass starts decomposing the Corallianassa eat them. You'll find several posts discussing them here if you do a search.


  12. Asbjorn gets the gold star today. Echiura is a group of small soft-bodied worms that many consider to be a subgroup of Annelida, the phylum that contains polychaetes, earthworms, & leeches. Usually the proboscis is simple but in the family Bonellidae the proboscis is T-shaped. Nearly all echiurans feed by extending the proboscis (which is highly contractible and attached outside the mouth) then collecting bits of detritus & tiny animals which are moved back to the mouth by synchronized tiny hairs called cilia.


  13. Marli's right too, it's just that her sources are a little out of date. :) Dendronotus regius was described in 2008. It's still listed as Dendronotus sp 2 on the Sea Slug Forum and as undescribed in the most recent IP slug books.

×
×
  • Create New...