Lyssianasid amphipod forces scientists to rethink definitions

Amphipod in a biosphere

This amphipod is a freshwater cousin of the recently-discovered lyssianasid amphipod. Image from Flickr.

For decades, scientists have worked under the assumption that life, as we know it, is possible only in a very narrow set of circumstances. However, with the recent discovery of the lyssianasid amphipod, a distant cousin of the shrimp you had as an appetizer last weekend, that belief is being quickly broken down. Sure, none of these deep-sea creatures are going to be running a personal loan company anytime soon, but they are already blowing scientists away with their achievements.

What is a lyssianasid amphipod?

The Lyssiansid amphipod is a member of the Lysianassidae family of amphipods. Amphipods include more than 7,000 shrimp-like creatures with exoskeletons – their bones on the outside of their body.

This particular lyssianasid amphipod was captured on video by NASA scientists exploring the underside of Antarctic ice with video cameras. The scientists did not expect to see anything except bacteria in this subfreezing, ultra-dark water – so when this little pink amphipod parked itself on the camera cable, they were truly surprised.

Why is this lyssianasid amphipod special?

With more than 7,000 classified amphipods, what is so special about this lyssianasid amphipod? It’s special because it was not expected. For a very long time, scientists assumed that anything above a bacteria could not survive in the extreme environments on the planet.

However, as the Christian Science Monitor points out, this lyssianasid amphipod is just a part of the more than 500 new types of marine species that are discovered every year by scientists, some with small cash loans, others that are very well-funded. Some, like the recently-discovered lyssianasid amphipod, live in water that is so cold and dark the conditions mimic some of Jupiter’s moons. Other creatures live in water that can get hotter than 700 degrees Fahrenheit.

What does the discovery of the lyssianasid amphipod mean?

To make a very long story short, this lyssianasid amphipod is forcing scientists to rethink their definitions of “habitable.” Conventional wisdom has held for a very long time that life simply cannot exist outside of the very narrow band of environmental factors on our planet. However, creatures we are discovering in our own oceans are forcing a rethink of this. With a new, wider definition of where life can survive, it becomes theoretically possible that creatures above bacteria on the food chain could live much, much closer to our own planet than we had ever thought. Beyond “Men from Europa” or “Men from Mars,” though, the lyssianasid amphipod is proving to us that our own oceans still have plenty of surprises buried in the depths.