Saturday, November 8, 2014

Fishy Beginnings

It was with great pleasure that I read of the discovery of a fossil representing an amphibious basal ichthyosaur. The ichthyosaurs were "fish-lizards", basically the "reptilian" ("reptile" being an outdated term due to paraphyly) equivalent of the mammalian cetaceans. The ichthyosaurs eventually evolved to become so committed to a solely aquatic existence that, while some early forms gave birth on land, the more derived forms gave birth to live young underwater. The ichthyosaurs became a diverse group of critters, featuring such amazing beasts as the huge-eyed Ophthalmosaurus, which probably dove into the stygian darkness of deep waters, and the sperm whale-sized Shonisaurus

The discovery of a primitive ichthyosaur that could function on land much like a seal is significant because it potentially allows paleontologists to determine what terrestrial lineage the transition ichthyosaur evolved from.

Recently, many gaps in the evolutionary history of whales have been filled in. To see a similar expansion of our knowledge of another great lineage's "back to the sea" trajectory makes me positively giddy. Despite the bleatings and blatherings of creationists, the gaps in the great chain of being keep getting filled in, making for a more complete evolutionary narrative.


mikey said...

Yes. It is remarkable, the things we know and the things we are capable of knowing.

And we have people who deny what we know, who deny our capability for learning, and who refuse to recognize the incredible things we've already discovered.

We've directly imaged exoplanets. We've directly measured the universe a mere 200K years after the Big Bang, we've measured the motion of stars around the supermassive black hole at the center of our galaxy, we've mapped the most fundamental substance of substance. I could go on and on, but the point is that to reject the majesty of the universe in the name of a silly just so story written more than a thousand years ago is to miss the excitement of our time...

ifthethunderdontgetya™³²®© said...

Hippos: A whale of a tale. (Or tail, if you prefer.)

"What Thewissen is saying is that Indohyus is the closest relative of whales - and we agree. Where we think he is wrong, is that he is saying that that hippos are more closely related to true pigs than they are to whales," says Theodor. "This contradicts most of the data from DNA from the last 12 or 13 years. Those data place hippos as the closest living relative to whales."

She says Thewissen did not use DNA evidence, instead used fossil evidence alone to create a family tree and reach the conclusion that hippos have more in common with pigs than whales.


ifthethunderdontgetya™³²®© said...

P.S. Needs a "I blame fish" tag.