Friday, May 4, 2012

Wow! Urasterias Vs. Amphipods! BONUS Echinoblog!

Last night I found this..
A video that shows the Arctic asteriid starfish Urasterias linckii just PLOWING into a field of creepy caprellid amphipods!  This looks like it might be feeding or possibly the opposite-defending itself?. Are the pedicellariae "batteries" on the side being used? Do these species typically interact?  Many mysteries!

As a caveat-this video could have been staged, obivously some time lapse was used, not sure. but it IS pretty cool and is I think the first time I have EVER seen Urasterias alive in a video! So, enjoy!

here's some better pics of the animal itself I found on Flickr
Urasterias linke 1
Photo by Alexander Semenov
And a close up of the MANY pedicellariae. They are quite abundant and pretty frakking HUGE!
Urasterias linke
Photo by Alexander Semenov

If you want to why/how the pedicellariae might be used in feeding click first on this intro post  and then there's this earlier post about asteroids feeding on moving prey! (and on Labidiaster-the king of starfish predators on moving prey!)


Anonymous said...

This is awesome. Has anybody else observed similar phenomenon with genus Pisaster?

ChrisM said...

Pisaster ochraceus lives in a very different setting (the turbulent intertidal) than Urasterias and feeds mostly on mollusks-especially mussels.

P. bevispinus is mostly a soft-bottom feeder going after infaunal clams and so forth

P. giganteus is more of a generalist but there's been no evidence that it feeds like this. IF indeed that is what Urasterias is doing. We shall see...