BOTH LITTLE KIDS AND MARINE BIOLOGISTS KNOW STARFISH BY THEIR FIVE ARMS. The starfish anatomy that lurks underneath a starfish’s bumpy skin is another thing (To be clear, the biologists know sea star facts, the rest of us not so much). There are 1,500 to 2,000 species of starfish, or sea stars, found in oceans worldwide, in pretty much every depth and type of habitat. They’re all alike in general architecture but come in a myriad
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WITH FIVE ARMS STRETCHING IN FIVE DIRECTIONS, you’d think that starfish could move along the seafloor like Indiana Jones. In fact, usually they creep along on hundreds of little tube feet that line the undersides of those arms. But, researchers studying how starfish walk found something else: sometimes starfish bounce along for speed. As echinoderms in Class Asteroidea, starfish walk by operating their multitudes of little tiny feet through intricate networks of fluid-filled canals. With
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SQUID CAMOUFLAGE WOULD APPEAR TO BE A TOUGH CHALLENGE. Squids’ cephalopod cousins, like bottom-dwelling octopuses and cuttlefishes, can disappear by blending in with the nearest coral. As free swimmers, squids have to find a way to hide out in the midst of open water. So the question is, how do squids manage their colors to disappear in plain sight? IT’S ALL IN THE IRIDOPHORES As it turns out, as explained by the folks behind PBS’ terrific
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BARNACLES HAVE BEEN DESCRIBED AS SHRIMP THAT STAND ON THEIR HEADS AND FLYFISH WITH THEIR FEET. Despite the hard mollusk-like shells they build, acorn and gooseneck barnacles are crustaceans, related to shrimps, crabs and lobsters. Look closely and you’ll see fine, feathery extensions constantly being flicked into the current from within those shells, like expert fishermen casting and recasting into a stream. The creatures within use these “cirri” – adapted leg-like appendages – to capture
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AS ANIMALS THAT SPEND THEIR LIVES HIDDEN INSIDE HARD, PROTECTIVE SHELLS, IT’S EASY TO OVERLOOK BARNACLES. In fact, they may be subtle but they’re fantastic, busy little guys, always working the plankton for edibles. Need evidence? Here are some random barnacle facts. 1 Acorn and gooseneck barnacles are both crustaceans in the cirripedia subclass – cirripedia reflecting their singular adaptation of their legs into cirri used for capturing prey. 2 They’re the only crustaceans that are
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FOR A LONG TIME, DURING MY NEW ENGLAND DIVING DAYS, the northern moon snail (Euspira heros) represented a mystery to me. I kept seeing these structures I knew were moon snail “sand collars,” mucus-bound masses of sand that were said be be egg-laden. Except that there didn’t appear to be any eggs. SANDY SAND COLLARS MOON SNAIL SAND COLLAR MYSTERY SOLVED Then, one day, I found this: BIGFOOT SIGHTED! Thinking about moon snails brings to
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THERE ARE TWO KINDS OF DIVERS: THOSE WHO ARE BONKERS ABOUT NUDIBRANCHS and those who ought to be. For those in the second category, here are some nudibranch facts. First, as the name “nudibranch” suggests – it’s from the Greek for “naked gills” – nudibranchs absorb their oxygen from the water through external breathing structures located on their backs. There’s great variation in gill architecture among the many species of nudibranchs, from flamboyant to demure. And
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WITH FLAMBOYANT SWAGGER, NUDIBRANCH COLORS CALL ATTENTION TO THEIR SLUGY TORSOS – and that’s the point. As beautiful as they are, nudibranchs’ bright markings are statements telling potential predators to leave them alone. In brief, nudibranch tissues tend to be foul-tasting, if not toxic. Nudibranch’s colors are warning signs to potential predators that they’ll regret attempts to dine out on their nudibranchy flesh. There are other nudibranch defenses in the mix, as well. Some have
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IT MAKES SENSE THAT YELLOWLINE ARROW CRABS would want to hang out with long-spined sea urchins. After all, it should be a gimme that these crustaceans with 10 long, thin legs would seek to blend in with urchins whose most visible features are long, thin spines. On the other hand, the sources seem to put Stenorhynchus seticornis all over the place – atop sponges, sea fans and other gorgonians, under and next to sea anemones.
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GIVING THE PARTY DRUG ECSTASY TO OCTOPUSES may sound like a joke from a slacker movie. Some news stories about the research have taken a humorous tack, talking about how octopuses on Ecstasy become huggy. But, in fact, the study has a serious goal and may result in improved understanding of evolution and treatment of human afflictions like post-traumatic stress disorder. IT’S ABOUT THE GENES Johns Hopkins University’s Gül Dölen and Marine Biological Laboratory’s Eric
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