A decade after their first brief appearance, huge purple jellyfish were sighted off San Diego last week. The strange floaters can have tentacle spans up to 30 feet, and are the largest invertebrates identified this century.
In the summer of 1989, thousands washed up on beaches from Baja California to Santa Monica. But by September, the creatures had disappeared.
Very little is known about the jellyfish's eating habits, habitat, or even how--with its considerable size and striking color--it escaped notice until the first massive wash-up.
Jody Martin, curator of crustacea at the Natural History Museum of Los Angeles County, and his colleagues named the species Chrysaora achlyos. Chrysaora is the larger family to which the jellyfish belongs; achlyos comes from the Greek word meaning darkness, mistiness and obscurity.
Despite their size, the jellyfish are no more dangerous than their more diminutive kin.
"If you're at the beach and start seeing a bunch of them in the water," Martin said, "think about packing up and not swimming anymore. It's not a really painful sting, but it's no fun, either."