Steve Carrell in "The 40-Year Old Virgin" was complaining because he was exactly that - a 40-year old virgin. But apparently, that's nothing compared to these bdelloid rotifers, who just happened to remain virginal for -- get this -- 40 million years.

Yep, never been touched, never been kissed. The bdelloid rotifers are actually microscopic aquatic animals that usually dwell in watery or occasionally wet habitats like ponds, rivers, soils, mosses and lichens. What's baffling scientists is the fact that they have managed to evolve into distinct species despite of the fact that there are absolutely no males in their group. Asexual, these animals are, indeed.

So how do they generate offsprings? Well, they are still able to produce eggs that are deemed to be genetic clones of their mothers. To better understand this phenomena, scientists took a close look at bdelloid rotifers from UK, Italy and elsewhere. Evolution for these creatures, as they found, were more adaptive than genetic.

According to Dr. Tim Barraclough of the Imperial College London's Division of Biology posits, "we found evidence that different populations of these creatures have diverged into distinct species, not just because they become isolated in different places, but because of the differing selection pressures in different environments."

What makes this finding highly significant is that it was previously believed that in order for speciation to happen, there ought to be sexual reproduction involved. Adds Dr. Barraclough, These are really amazing creatures, whose very existence calls into question scientific understanding, because it is generally thought that asexual creatures die out quickly, but these have been around for millions of years."

To learn more about this findings, you can catch the published study in today's edition, March 19, 2007, of PLoS Biology.