|Image by Geir Friestad via Flickr. Norway I think.|
|from this EOL page via SERPENT Media Archive|
Note that the white "dots" above and the finger-like yellow bits below are the papulae- aka the gills! This is how the animal "breathes".. Image by Mark Craig
In 1915, zoologist James F. Gemmill described what he observed to be filter feeding using the numerous tiny cillia covering the body of this species.
Dr. Gemmill was quite an authority..being an M.A., M.D. D.Sc, F. Z.S."!!! And is pretty well known historically for a number of significant contributions. He dropped little red carmine particles (basically a red dye made up of a fine powder) on P. pulvillus and watched them move over the surface..
A quick reminder about basic biology of this (and all starfish). The epidermis COVERS the body! The epidermis is in turn covered by tiny hair-like structures called cilia, which are usually in constant motion.
These little particles were moved over the body and apparently headed towards the mouth. Here's his diagram showing the little arrows apparently indicating how water was flowing to the mouth.
|Fig. 2 from Gemmill 1915|
|Image by Christine Howson via Flickr|
|Image by Tony J. Gilbert|
Perhaps P. pulvillus is sort of an opportunistic predator in addition to the "suspension feeding" with mucous threads?
Is this Porania pulvillus getting ready for a big banquet? Or is this the echinoderm version of those "1 dog, 1 pig, and a cat" pet adventure stories?
|Image by www.ilreporter.com|
It turns out that what we are seeing here is probably something unreported! NEW!! A previously undocumented feeding interaction!!
|From this EOL page via SERPENT|
Here's a nicer pic of the sea pen...
|Image by Jarle Strømodden via Flickr|
Again-this was a NEW discovery! What does it mean for this animal's ecology? Does it mainly feed on yummy cnidarians? Is the species more opportunistic than thought? More predatory than previously thought??
And of course.. there's the impact on the bottom fauna.... I've written about goniasterids that feed on deep-sea coral (here) and here's a video about them from MBARI a few years back...
These types of interactions are important owing to our interest in deep-sea corals and their role in biodiversity and conservation of deep-sea ecosystems..
But after looking at the pic above from the SERPENT pool on EOL, I discovered several more...
Some further interesting feeding observations of Porania pulvillus, such as this one of it hunched over this rock and possibly feeding on the polychaete worm Pomatocerus sp. (which makes up the tubes). And of course, there could be hydroids or other encrusting goodies on there as well...
|EOL page link here SERPENT Media|
|From this EOL page working w/ SERPENT Media|
|From the EOL page here SERPENT Media|
|From EOL page by SERPENT media|
|From the EOL page SERPENT Media archive|
Bear in mind-if these things had been thought of as primarily suspension feeders for years and years-and it turns out they're big time predators??? That would represent a big shift in understanding the ecosystem/food web in this area. Sometimes it can all be in the details..
And there's MORE??
With my appetite teased I spread out a little more and went looking on Flickr!
Feeding on some green stuff! Algae? Hydroids? Image by Gordon.Milligan
Or maybe gettin' ready to go after those tunicates in the upper right hand corner?
Feeding? Or getting ready to spawn?
|Image by Mark Craig via Flickr|
Thanks to Jen Hammock, EOL, the SERPENT Media Project and all the photographers cited!