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Phronima- are they aliens or amphipods?

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Happy Thursday from the middle of the Gulf!

Phronima, a deep sea hyperiid amphipod, is a type of crustacean that looks like an alien! We have been pulling these little creatures up in the nets the past few days and they are quite intriguing looking. I can’t help but think of my son Noah and how excited he would be to see one of these, I’m pretty sure he would be mesmerized! It’s amusing how the inner child comes out in all of us when we bring in the nets and look over the samples; it’s like Christmas morning!

 Phronima is considered an ambush predator with really large claws in relation to its body size. It uses large claws to tear apart its prey and its tiny mouth to shred. This organism likes to maintain its secrecy in the deep sea by hiding inside a semi-hard gelatinous barrel. This barrel seems to serve as its habitat and protection from others by camouflaging itself. The amphipod feeds on organisms such as salps (gelatinous zooplankton), jellies, and siphonophores, but it doesn’t just eat them. Some sources say that the Phronima reuses the gelatinous material from its prey and builds a barrel. Somehow the amphipod harvests some of the living cells from its prey and builds the structure.


               b2ap3_thumbnail_holding.jpg                b2ap3_thumbnail_Amphipod-Phronima.jpg

So why would an animal do this is? What is the benefit?  The barrel could possibly provide protection by allowing the animal to flawlessly blend in. If a predator attacks it will first come into contact with the barrel, not the amphipod, increasing its chances of survival. Energy efficiency could be another possible benefit. The barrel may allow this organism to maintain buoyancy, which could allow the amphipod to travel farther, and in turn be exposed to a variety of food sources in the water column. There is some research that suggests that their barrel behavior may be a type of symbiosis as well.  


Another cool feature on these amphipods is their enormous compound eyes. There is recent research that in the species Paraphronima gracilis, their compound eyes have 32 retinas, 16 in each eye, which scientists have never seen in any other arthropod species before, the function is still unknown.  This could be an evolutionary adaptation as a response to living in the deep sea. You can read more about it at the link below.

There are many more cool stories to tell about the amazing creatures we are finding! Keep checking back for more!



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Guest Wednesday, 13 November 2019