Thursday, November 15, 2012

Meat-Eating Sponges?

Relax. You’re not likely to encounter one of these carnivorous sponges. They live about 2 miles below the ocean’s surface, and the biggest ones found so far are only about 14 inches tall.

Its scientific name is Chondrocladia lyra, but it’s better known as the “harp sponge” for its unusual, and beautiful form. It was actually discovered in 2000 by scientists using a deep-diving, remote operated vehicle, but researchers only reported its existence in an article published in the journal Intertebrate Biology in October 2012. It lives deep in Monterey Bay off the coast of California.

Scientists have known of the existence of carnivorous sponges for less than twenty years. But little was known about their lives since they usually live in very deep water. But researchers were able to retrieve two live specimens which allowed them to study the sponges in some detail.

Harp sponges use barbed hooks which cover their branching limbs to catch their dinner. They wait for tiny fish and crustaceans to be swept past them by deep-sea currents, then wrap their prey in thin membranes while they slowly digest their victims.

They also have an interesting way of reproducing. While most sponges release their sperm to swim in the water around them, all carnivorous sponges studied so far transfer their sperm in condensed packages. The swollen balls at the tips of the sponges’ branches hold these sperm packets, releasing the spermatophores into the passing currents. When other sponges capture the packets, the sperm works its way into its new host from the packets and fertilizing their eggs. These sponges are able to produce both sperm and eggs, although they cannot fertilize their own eggs.

The discovery was made by Senior Research Technician Lonny Lundsten of the Monterey Bay Aquarium Research Institute, which has made other remarkable discoveries in the past, including a squid which has elbows.

If you’re interested in seeing a photo of this interesting new animal, go here

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