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| An artist's rendition of the amphibious Cartorhynchus lenticarpus. (Stefano Broccoli) |
My absolute favorite moment of the study though had to be the team's conclusion that the foot and a half long green amphibian "probably had a happy life". I could see now a room full of white lab coats concurring with one another. "Yes yes, happy indeed. I concur." A young lab technician then sheepishly speaks up. "I must disagree sirs. My research shows its not easy being green." "Oh yes, yes," the group of senior scientists now concede. "Indeed, it's not easy being green."
Motani's statement that his team now hopes to find the preceding evolutionary ancestor to Cartorhynchus lenticarpus as their next major breakthrough is the part of this report that I can't get out of my mind. What would the odds be that this small group of researchers not only find one crucial missing link, but will also discover the very next missing piece of the long evolutionary puzzle chain, evidence countless archeologists, scientists and researchers have been, for centuries, turning over stones in search of. Something smells fishy here, and it isn't the great, great, great grandfather of Kermit the Frog.
Greg Giles
Excerpts from the washingtonpost.com article by Rachel Feltman:
Researchers report that they've found the missing link between an ancient aquatic predator and its ancestors on land. Ichthyosaurs, the dolphin-like reptiles that lived in the sea during the time of the dinosaurs, evolved from terrestrial creatures that made their way back into the water over time.
But the fossil record for the lineage has been spotty, without a clear link between land-based reptiles and the aquatic ichthyosaurs scientists know came after. Now, researchers report in Nature that they've found that link — an amphibious ancestor of the swimming ichthyosaurs named Cartorhynchus lenticarpus.
"Many creationists have tried to portray ichthyosaurs as being contrary to evolution," said lead author Ryosuke Motani, a professor of earth and planetary sciences at the University of California Davis. "We knew based on their bone structure that they were reptiles, and that their ancestors lived on land at some time, but they were fully adapted to life in the water. So creationists would say, well, they couldn't have evolved from those reptiles, because where's the link?"
Now the gap has been filled, he said.
The creature is about a foot and a half long and lived 248 million years ago.
"Initially I was really puzzled by this fossil," Motani said. "I could tell it was related [to ichthyosaurs], but I didn't know how to place it. It took me about a year before I was sure I had no doubts."
One of the most important differences between this new ichthyosaur and its supposed descendants comes down to being big boned: When other vertebrates have evolved from land to sea living, they've gone through stages where they're amphibious and heavy. Their thick bones probably allowed them to fight the power of strong coastal waves and stay grounded in shallow waters. Sure enough, this new fossil has much thicker bones than previously examined ichthyosaurs.
"This animal probably had a happy life. It was in the tropics, and it was probably a bottom feeder that fed on soft-bodied things like squid and animals like shrimp," Motani said. "And for a predator like that to exist, there has to be plenty of prey. This was probably one of the first predators to appear after that extinction."
This single fossil hasn't revealed all of the ichthyosaurs' secrets. Motani hopes to find the preceding evolutionary ancestor next — one that was also amphibious, but spent slightly more of its time on land. "We're looking for that one now," Motani said.
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