01 October 2007

A bdelloid from Colorado

Bill Birky from the University of Arizona sent these pictures of a bdelloid rotifer yesterday. He was hoping that I would be able to identify the species.


I had to disappoint him, unfortunately. One reason why I stopped working with bdelloids was that the darn creatures were so hard to identify. There really is no way to preserve them; one has to work with live and active animals (hence, no morphological type specimens). Moreover, to confirm the identifications of most individuals it is necessary to observe them while they are feeding with the ciliated lobes (the corona) around their mouths open (the bdelloid in the picture had its corona open). But if the specimens you wanted to identify didn't feel like feeding, you could wait at the microscope for hours while fuming at an animal smaller than a millimeter for wasting your time.

The food particles a bdelloid ingests pass thru its jaws, called the trophi and which happen to be the only hard parts in their bodies. The picture below shows the trophi of this unidentified species of bdelloid.


Bill Birky found these animals at about 7,100 feet (2165 m) in northern Colorado. He indicated that they have a stiff body wall, a pair eye spots and 4 toes. The latter is important to know to be able to place them in a genus. He also thinks they may be viviparous. My best guess is that they may be an Embata sp.

Both pictures are from Bill Birky. The colors are not the actual colors. Most bdelloids have colorless, translucent bodies.


Frank Anderson said...

Bdelloids are awesome. There are no morphological type specimens? That's surprising -- the trophi can be preserved, though, right? With all those sophisticated preservation methods that have been developed over the past 200 years, we don't have a good one for bdelloids?

I'd love to know more about these guys (no sex for perhaps tens of millions of years! -- very cool), but they're so tiny, and my microscope technique...well, it sucks. There's a reason why I work on big squid, fairly big land snails and DNA -- I only ever need a dissecting scope!


The trophi can be preserved, but they are not by themselves enough to identify species.

Gilles Arbour said...

My 7 years old grand-son came for a visit a few weeks ago. We went to a store to purchase a gift of his choice. To his mom's surprise he wanted a microscope!

We looked at dirty water from the bird bath. He was interested by the mosquitoes larvae but what really fascinated him were the rotifers. He couldn't stop looking at them.

At one point he turned around and declared "I love Science". So you'll have a new colleague soon. I'll send him the links to your rotifers posts.

I'm just an amateur naturalist without any formal scientific training, but I am happy to expose him to basic observation and stimulate his desire to ask questions and learn.

Thanks again for your great blog. I come and visit almost every day.