So says a new genetic study that examined samples from 4,283 individual sharks. It found 574 species, and 79 of these are likely new species.
These new species are actually cryptic species. A cryptic species is one that is suddenly discovered from a population of what appear to a species already known to science, or it can happen when two populations that have been classified as the same species turn out to have quite a bit more genetic diversity than was previously thought.
For example, Naylor’s work suggests that the endangered scalloped hammerhead (Sphyrna lewini) is actually two separate species. “Scalloped hammerheads in general have taken a huge hit, so it may be even worse than has been documented if there’s more than one species out there,” he says.
Now, this is really an interesting find.
I’ve often wondered if our traditional classification of shark species would withstand molecular genetic analysis.
It doesn’t look like it will.
For example, I’ve often questioned whether all the sand tiger sharks (Carcharias taurus) are all really of the same species. These sharks are found only near coasts, and they are found in quite isolated populations in different parts of the world.
I bet there isn’t much gene flow between those populations– if any– and they likely have been reproductively isolated for a fairly long time.
Sharks have been around for a long time, and even modern species have had more than enough time to experience multiple divergences from a common ancestor.