Week 14 The Bone eaters

I am being a little too literal in interpreting the assignment, but I figured if I need to pick an animal that I know NOTHING about, I should pick one I never heard of before. How should I look for such a mysterious animal?

I started with remembering our whale skeleton. Shawna was telling us how lucky we are to have such a specimen. Lucky indeed! I had heard rumors that it is much more difficult to acquire a dead whale today. Thank goodness we recovered it when we did. The reason is that now we know that there are whole whale decomposition communities with species that are only found on dead whale carcasses in very deep water. Today a dead whale is more likely to be towed out to sea to feed the critters at the bottom of the ocean. We have only become aware of the complexity of whale-fall communities in the last 10 years. It is likely that many species from that community have gone exinct in the last 200 years due to whaling (http://books.google.com/books?id=hKoUnp_YaPAC&pg=PA345&lpg=PA345&dq=whale+carcass+decomposers&source=bl&ots=UEDfein0BD&sig=w0hLeWP9fDVoGMB6vY74ZOOY_wA&hl=en&ei=Kz_VS9OlOcH6lwfXhK3MCA&sa=X&oi=book_result&ct=result&resnum=7&ved=0CBcQ6AEwBg#v=onepage&q=whale%20carcass%20decomposers&f=false )

In 2004, one genus was discovered that decomposes whale bones, Osedax . http://www.mbari.org/news/news_releases/2004/whalefall.html

I choose one of those-- Osedax frankpressi
Phylum Annelida , Class Polychaeta, Order Canalipalpata, Family Siboglinidae .

The family includes the giant tube worms that are found near deep sea vents. http://en.wikipedia.org/wiki/Siboglinidae

The Osedax species' nearest relatives are those deep sea vent tube worms. This makes sense. None of the adults of this family eat. All of them are dependent on symbiotic bacteria for their energy needs. DNA studies have shown that the whale bone decomposers diverged from the sea vent tube worms 30 to 45 million years ago, just as whale-like creatures started inhabiting the oceans. http://www.biomedcentral.com/1741-7007/7/74  .  Evidence of Osedax "feeding" activity has been found on whale bone fossils that are 30 million years old. http://www.sciencecodex.com/boneeating_worms_30_million_years_old

Here are some pictures and a video of present day Osedax:  http://www.hartnell.cc.ca.us/faculty/jhughey/Files/osedax.jpg,

http://www.mbari.org/news/news_releases/2009/osedax-spp/osedax-spp-images.html

Here is a diagram of Osedax:   http://spineless.ucsd.edu/NewFiles/Osedax.gif

These "worms" consist of a tube with feathery tops. The bottom of the animal consists of roots that burrow into the bones of whales. The roots contain Oceanospirillales bacteria. These bacteria produce enzymes to hydrolyze collagen. http://rspb.royalsocietypublishing.org/content/275/1633/387.full
Cholesterol, fats, and collegen in the bone are thought to be food sources for the bacteria housed in the roots of Osedax.

All of the visible adults of this genus are females. This was a mystery for a while until it was found that males were tiny, almost larval, forms that attach to the inside of the female's tube. The live off the energy provided by their yolk sac.    It has been postulated but not yet proven that larva that land on bones become female and larva that land on females become males. http://www.biolbull.org/cgi/content/full/214/1/67  . The females produce copious amounts of eggs http://www.springerlink.com/content/k5053278k5m86733/ . This also makes sense, because once the bone pile has disappeared finding the next dead whale on the vast sea floor must be a daunting task.  The larvae are microscopic trochophore that can swim 9 to 16 days. That hardly seem long enough to find a new carcass.