While exploring an underwater ridge in the South Pacific, a team of researchers aboard Okeanos Explorer, a research vessel for the National Oceanic and Atmospheric Administration (NOAA), witnessed one really cool invertebrate battle recently. 

The clash between a free-swimming squid and a group of brittle stars was captured during a dive off the coast of Jarvis, an uninhabited coral island about halfway between Hawaii and the Cook Islands. This kind of interaction is so rarely seen that it's been filmed only once before.

"[This is] one of the most amazing echinoderm-related natural history moments that I've seen in a while!" writes starfish expert Dr Christopher Mah on the EchinoBlog

Unlike true starfish, which hover around atop hundreds of tube feet, brittle stars (or "snake stars") can move quite quickly across the seabed – their superior motoring comes down to those long, wriggling arms – but even so, these creatures are largely known as scavengers or filter feeders. 

After watching the clip, some online commenters suggested that the stars didn't actually eat their cephalopod captive, but Mah assures readers that the meal was indeed devoured. In fact, he points out, similar behaviour was caught on camera back in 1996:

Just as in the video above, chances are the various stars involved in the Okeanos catch got a chance to tear off a chunk of leftover calamari. In brittle star communities, it seems, sharing is caring. 

"Spines in these brittle stars are sharp and often with jagged edges ... so capturing something soft-bodied isn't too surprising," writes Mah.

The Okeanos team hopes that this and other records from their dives around Jarvis will shed some light on how offshore communities here rely on one another. Much of this region has yet to be mapped – in fact, large swathes have never been seen by human eyes. 

"These are the kinds of behaviours that you would never see in a textbook," says the team. "It really takes getting down there and watching."

For more on the interaction, including a closeup of brittle star teeth, head on over to the EchinoBlog!

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Top header image: Patrick Randall/Flickr