New carnivorous sponge gives its prey the kiss of death

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A carnivorous sponge with ‘lip-shaped’ spicules has been identified from the dark depths of the ocean.

“This unusual sponge is shaped like a large feather, whitish in colour, and is covered with lip-shaped spicules. “Spicules are like tiny bones that go together with much larger spicules to form the skeleton of the sponge. The spicules give the sponge its stiffness and allow it to stand upright and to extend its filaments out like a feather into the water to catch prey,” says NIWA marine biodiversity scientist, Dr Michelle Kelly.

“The sponge is new to science, probably a new genus, and was found on the Macquarie Ridge to the southwest of New Zealand in 2008. Despite numerous surveys all around New Zealand, the Macquarie Ridge is the first place that this species was found. A colleague has found a similar sponge off Patagonia, and we are presently comparing it with the New Zealand species.”

Marine scientists are discovering species that are new to science all the time. The ocean is full of mysteries, unknown species, and never-before seen phenomena.

The first discovery of a carnivorous sponge was made just 15 years ago – in 1995 – by Professors Jean Vacelet and Nicole Boury-Esnault in submarine caves in the Mediterranean Sea.  “It changed the way we think about the sponges. Until then, they were known only as filter feeders.”  Since then, Kelly has discovered about 34 species that she and Vacelet think might also be carnivorous.

Found in the depths and darkness around 1000 metres down in the ocean, the new species is quite large at 8– 10 cm tall. It lives on rocky basalt surfaces with other species of carnivorous sponges.

They are members of the Cladorhizidae family (although even the integrity of this group is now in question because there are so many weird sponges being discovered), and are very often small and feathery. 

The lip-shaped spicules which cover the outside of the sponge, much like sticky Velcro, catch prey such as crustaceans that brush against them. The sponge doesn’t have a mouth or a stomach, so the cells of the sponge stream toward the prey to engulf its flesh, each cell digesting a tiny part of the captured animal.

New Zealand appears to have high species numbers of some groups of sponges in relation to diversity elsewhere in the world’s oceans. These include carnivorous sponges, rock sponges, and glass sponges. “We have discovered some pretty amazing biodiversity and evolutionary hotspots around New Zealand,” says Kelly. “The only way to count, describe, manage, sustain and protect our precious marine biodiversity is by taxonomy, the differentiation of one species from the other. Taxonomy underpins all our conservation, preservation, and management efforts,” says Kelly.

Dr Kelly has been studying carnivorous sponges since 2007. This project is funded by the Foundation for Research, Science and Technology.

Species fact file  

Type:  Sponge
Family: Cladorhizidae
Diet:  Tiny shrimp like organisms
Lifespan:   Not known
Size: 8–10 cm tall

Habitat: Carnivorous sponges seem to be able to live at great depths because of their feeding habit.

There is not a lot of filterable food at the >1000 m  so these sponges seem to have evolved a prey capture mechanism to take advantage of these opportunities in the deep sea

Something strange: The lip-shaped spicules look like human lips
Reproduction:They are thought to incubate larvae within the stem or main part of the feather. The ectoderm (dermis) breaks down and the larve probably swim and settle.

Contact

Macquarie Ridge carnivorous sponge [Photo DTIS, NIWA]
Research subject: Biodiversity