[ad_1]
Tiktaalik was first recognized by humans in 2004, when the skulls and other bones of at least 10 specimens were found in ancient stream beds in the Arctic’s Nunavut Region. A team of paleontologists, including explorers Neil Shubin of the University of Chicago, Ted Daeschler of the Academy of Natural Sciences in Philadelphia, and Farish Jenkins of Harvard University, described their findings in two parts. Nature papers in 2006.
A local council of elders, known as the Inuit Qaujimajatuqangit Katimajiit, was consulted and gave the Tiktaalik its name, which in Inuit means a large freshwater fish that lives in the shallows. The fossils have since been returned to Canada.
For decades, scientists had been looking for a fossil like Tiktaalik, a creature at the pinnacle of limbs. And where other fossils need some explanation, Tiktaalik’s obvious anatomy—a fish with (almost) feet—made it the perfect epitome of evolution, nestled exactly between water and land.
Even then, fossil fish hit a popular nerve and came just after a case. Attempt He decided against teaching creationism as an alternative to evolution in high school biology in Pennsylvania. According to Shubin, society’s desire to throw the Tiktaalik back into the water is somewhat comforting: The fish would only be a good thing if you believed in evolution, he said.
When Ms. Deretsky painted Tiktaalik, she depicted him with his joint submerged in water, as the back half of the fossil was a secret at the time. But since then, scientists have collected more than 20 specimens and seen more of its anatomy, including the pelvis, posterior fin, and joints of the skull.
Specifically, Dr. Computed tomography scans taken by Justin Lemberg, a researcher in Shubin’s lab, allowed the scientists to look inside the rocks so they could see the bones. The scans revealed 3D models of unseen parts of Tiktaalik. Some scans revealed that Tiktaalik had unexpectedly large hips (more like Thicctaalik) and a surprisingly large pelvic fin. Instead of dragging itself like a wheelbarrow with only its front fins, the fish four fins to get around like a jeep.
Other scans revealed sensitive bones from the pectoral fin. Unlike the symmetrical rays of fish fins, Tiktaalik’s fin bones were distinctly asymmetrical, allowing the joints to bend in one direction. “We think this is because these animals interacted with the ground,” said Thomas Stewart, a new evolutionary and developmental biologist at Penn State University.
[ad_2]
Source link