Saturday, June 23, 2012

Hey swimmers, we found some more sharks!

Sharks more diverse than thought

A team of scientists have found there are many more species among sharks than we knew of.  That on the one hand gives us more and better information to use in studying them. One the other hand, it meas some that we thought were doing ok are actually less numerous.  After taking DNA from 4,283 specimens of sharks and rays, researchers found 574 species, vs the 495 they thought were represented by that sample and that 495 was only a chunk of the 1,400 or so thought to exist worldwide. (1,400 is a considerably higher number than we are used to reading, but there have been a lot of small types discovered and some significant species-splitting already in recent years.)  An interesting note in this article is sounded by another scientists who thinks this team may be off using genetics alone to map the shark family tree.  (As I have observed before, there is not universal agreement, or even a majority agreement, about precisely defining species based on differences in DNA.)
Meanwhile the sharks aer just going about their business, as they have for 400 million years.

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