Scientists have just discovered 3 new types of carnivorous sponge in the deep ocean

Even if we know the deep sea is weird, “carnivorous sea sponges” always look like something out of a sci-fi movie. And yet, researchers have just announced the discovery of three new species of this type off the Australian coast.

Go a few hundred feet deep into the ocean, and it starts to look like you in a whole new world: from a creature that looks like a starfish crossed with an octopus, to shark-eating fish, to carnivorous sponges. that we ‘I’ve never seen before.

“It shows how our deep oceans have yet to be explored – these particular sponges are quite unique in that they are only found in this particular region of the Great Australian Bight – an area which was intended for the ‘deep sea oil exploration,’ said one of the researchers, Merrick Ekins, director of the Queensland Museum’s collection of sessile marine invertebrates.

Typically, sea sponges are multicellular filter feeders – they have tissue with holes for water flow, from which their cells extract oxygen and food. They are fairly simple creatures with no nervous, digestive, or circulatory systems, but have been around in one form or another for over 500 million years.

Scanning electron microscope image of Oxyastres Acarnidae. (Ekins et al., Zootaxa, 2020)

But carnivorous sponges are a little different. Some carnivorous sponges still use the water flow system, while others (like the three newly discovered species) have completely lost this ability and catch small crustaceans and other prey with the help of filaments or hooks.

The researchers in this study discovered three new species of carnivorous sponges – Nullarbora heptaxis, Oxyastres Acarnidae and Lycopodina hystrix, which are also all new genera, as well as a closely related species of sponge that is not carnivorous, Guitarra davidconryi. All of these species have been found at depths between 163 and over 3,000 meters (535 to 9,842 feet) deep.

“Here we report four additional new species of sponges discovered in Great Australian Bight, South Australia. This area was recently surveyed using a Smith-McIntyre Grab and a Remote Operated Vehicle (ROV) to photograph and harvest marine biota ”, write the researchers in their new article.

“These new species are the first carnivorous species recorded from South Australia and increase the number of species recorded around Australia to 25.”

Sponges are also prettier than you might imagine, looking a bit like flowers with their thorny protrusions, but not much like sponges.

Close up of A. oxyaster. (Ekins et al., Zootaxa, 2020)

Carnivorous sponges have a little time. We have known them since 1995, but many more have recently been discovered around the world.

“Over the past two decades, our knowledge of the diversity of carnivorous sponges has almost doubled,” said the same team in a previous article, where they described their discovery of 17 new species of carnivorous sponges.

“[This is] in part thanks to the rapid advancements in deep seabed technology, including ROVs and submersibles capable of photographing and harvesting intact carnivorous sponges, and also the Herculean efforts of a number of contemporary taxonomists redescribing many more species. old ones described in the 19th and 20th centuries.

Almost every carnivorous sponge species found in Australia was discovered during a CSIRO RV investigative trip in 2017, showing just how important these deep sea investigations are.

With the ocean floor still largely unexplored, we imagine that we’ll see many more species of carnivorous sponges and other weird and wonderful sea creatures.

The research was published in Zootaxa.