[colorado tanker]

No matter how they looked at it, the lineages defined by their fossil forms "showed an imperfect but very good fit to the molecular data," Jablonski said. The fits were generally far better than random. The few exceptions included freshwater clams, "a complete disaster," he said.

So, what are those tasty bivalves related to???

[muawiyah]

Just did a quick check. You ask a good question. The answer is "invasion" ~ people and animals have been hauling these critters around to lakes and rivers for millions of years. The result is everything you could imagine.

Recently you've had African freshwater clams show up in Europe, and European clams in America, and American clams in Australia and Australian clams in China, and so on.

What a mess. And some of them are all male, and others are all female, and some of them just don't care.

No doubt there are doctorates waiting to be printed.