IF IT LOOKS LIKE A CRAB AND IT WALKS LIKE A CRAB, THEN IT MIGHT BE A PORCELAIN CRAB, which is a different thing entirely. Which leaves the question: What’s the difference between true crabs and porcelain crabs? They’re both decapods – crustaceans that resemble each other with hard outer shells and 10 appendages, including walking legs extending on their sides and large claws out in front. They both walk sideways, or “crab-like.” But the
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WEIRD AND WONDERFUL CREATURES, HORSESHOE CRABS are survivors from life’s earliest times who almost certainly have saved your life. And, they’re almost spiders. For the record, they’re not crabs in any way. If all that sounds overblown, consider the following horseshoe crab facts: 1) THEY’RE WEIRD & WONDERFUL Beneath their dome-like carapaces, horseshoe crabs walk around the seafloor on 10 legs and they view the world with 10 eyes spread around their bodies, some on
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WHAT’S THE DIFFERENCE BETWEEN FEATHER DUSTER AND CHRISTMAS TREE WORMS? For one thing, the conical feathery crowns of Christmas tree worms shout out their presence with color and beguiling shapes. Feather dusters’ fan-shaped crowns often whisper with subtle elegance. If it’s simply about appreciating the beauty of the reef, that’s the main point – conical versus fan-shaped, bold versus muted. It’s the fan shape that gives feather dusters their other common name, fan worms.
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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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