The squidgy lump in your bathroom has a more dangerous cousin that eats small animals, throws packets of sperm into ocean currents and can regrow its body parts.
A newly discovered carnivorous sponge is fascinating marine scientists - including two Greater Victoria sponge experts who were instrumental in studying the harp sponge and writing a paper to appear next month in the journal Invertebrate Biology.
"This was so attractive and so bizarre, I couldn't pass it up," said Henry Reiswig, adjunct professor at the University of Victoria and a research associate at the Royal B.C. Museum.
"Sponges don't usually get a lot of notoriety, but this is a pretty interesting animal," said Reiswig, after a video of the harp sponge - Chondrocladia lyra - went viral online.
The two specimens were found 3,000 metres beneath the surface of the Pacific Ocean off northern California. One of the sponges was sent to Victoria to be studied by Reiswig and Bill Austin, who runs the Khoy-atan Marine Laboratory in North Saanich.
Victoria has a wealth of sponge expertise, Austin said. "We call ourselves spongeologists."
Carnivorous sponges were first discovered about 20 years ago. There are about 130 known species, including some small ones living off the coast of Vancouver Island.
The delicate, white 40-centimetre specimen sent to Victoria after being collected by Monterey Bay Aquarium Research Institute's remote operated vehicle is something completely different.
"It's certainly another growth form. It's something we would never have predicted," Austin said.
"I worked on it systematically, trying to figure out who it was related to, and I put my neck out and said it was a different sub-genus."
The harp sponge has numerous fascinating elements, Reiswig said.
While most sponges eat bacteria, this sponge eats small copopods - crustaceans - it catches with the barbed hooks covering its harp-shaped vanes.
"It's sort of passive catching, as it snares them as they are swept past," Reiswig said. "Once they are caught, they are engulfed by the sponge cells and the sponge slowly digests them. Sometimes it takes a day."
Specimens brought to the surface have two vanes, but cameras on the remote operated vehicle have revealed sponges with up to six candelabra-type vanes.
Scientists also found that the harp sponge can regenerate body parts when a piece gets bitten off.
All carnivorous sponges are hermaphrodites and most disperse sperm, which other sponges then filter into their bodies with bacteria they are eating.
The harp sponge has refined the process and releases packages containing clumps of sperm into the water. The packages drift with the current and are captured by the branches of other sponges.
The sperm packages then fertilize the eggs of the host sponge.
The packages can drift for great distances and remain viable for weeks, Reiswig said.
"It has got away from the problem of sperm wastage," he said.
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