The reproduction of giant sea spiders in Antarctica has been a puzzle for over a century. Studying their habits requires deep dives under thick Antarctic ice in frigid ocean temperatures. Now, a group of scientists may have finally solved the 140-year-old mystery of why the giant sea spiders lay their eggs on the bottom of the seafloor, unlike other sea spider species who carry them around. The findings are described in a study published February 11 in the journal Ecology.
[Related: Sea spiders use their guts to pump oxygen through their freaky little bodies.]
Polar giants
Sea spiders belong to a group of invertebrates found in marine habitats around the world. These marine arthropods are in the order Pantopoda. They are related to, but not the same as land spiders who are in the order Arachnida.
While most sea spider species are smaller than a human fingernail, Antarctica’s giant sea spiders (Colossendeis megalonyx) have a leg span that is more than one foot apart. They can grow up to 20 inches wide, or the size of a dinner plate. C. megalonyx is a famous example of polar gigantism–where certain organisms in the Arctic and Antarctic grow larger than their relatives in warmer regions. Living on a diet of sea anemones, jellyfish, and other invertebrates.
C. megalonyx’ above average size and a unique parenting style sets them apart from other animals, not just those that live at the poles. Many sea spider species carry their eggs around until they hatch, in a behavior biologists call brooding.
“In most sea spiders, the male parent takes care of the babies by carrying them around while they develop,” study co-author and University of Hawaiʻi at Mānoa marine invertebrate ecologist Amy Moran said in a statement. “What’s weird is that despite descriptions and research going back over 140 years, no one had ever seen the giant Antarctic sea spiders brooding their young or knew…
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