A microscopic creature that lives in the mouths of lobsters belongs nowhere in the animal kingdom's existing categories, Danish zoologists have discovered.
The sack-shaped creature, named Symbion pandora, was identified three decades ago. But only recently did two researchers at Copenhagen University recognize that its anatomy and life cycle have never been seen before.The findings of Peter Funch and Reinhardt Moebjerg Kristensen were reported in this week in Nature magazine.
Measuring no bigger than the dot on an "i," symbion belongs to none of the 35 known animal categories, or phyla, according to Funch, a zoologist specializing in anatomy and morphology.
"The animal chiefly differs from other creature categories because its digestive system collapses and is reconstituted into a larva that is released to develop into a new adult," Funch told The Associated Press.
Funch and Moebjerg Kristensen created a new phylum - Cycliophora - to lodge the organism. The Greek word means the carrier of a small ring, Funch said.
The creature takes food from its host with a ring of waving hairs that sweep food particles into symbion's disc-shaped mouth.
The animal attaches itself to the lips of the host lobster with an adhesive disc like a suction cup. It reproduces both sexually and asexually.
The creature was first discovered in the 1960s by other scientists led by Tom Fenchel and Claus Nielsen, both of Copenhagen University. But the team did not have sophisticated equipment to investigate further and never discovered that the creature belonged to a category unto itself.
When Funch started writing a thesis in 1991, Nielsen urged him to look at the creature again.
"When looking at it in the modern microscope I rapidly realized that this was something different," Funch told the AP. "It's carapace was different." Symbion's carapace, or shell-like covering, was nothing like that of other organisms its size, he said.