Details Of Evolutionary Transition From Fish To Land Animals Revealed

ScienceDaily (Oct. 15, 2008) — New research has provided the first detailed look at the internal head skeleton of Tiktaalik roseae, the 375-million-year-old fossil animal that represents an important intermediate step in the evolutionary transition from fish to animals that walked on land.

A predator, up to nine feet long, with sharp teeth, a crocodile-like head and a flattened body, Tiktaalik's anatomy and way of life straddle the divide between fish and land-living animals. First described in 2006, and quickly dubbed the "fishapod," it had fish-like features such as a primitive jaw, fins and scales, as well as a skull, neck, ribs and parts of the limbs that are similar to tetrapods, four-legged animals.

The initial 2006 report did not describe the internal anatomy of the head, because those parts of the fossil were buried in rock. In the October 16, 2008, issue of Nature, the researchers describe this region and show how Tiktaalik was gaining structures that could allow it to support itself on solid ground and breathe air.

"We used to think of this transition of the neck and skull as a rapid event," said study author Neil Shubin, PhD, of the University of Chicago and Field Museum and co leader of the project, "largely because we lacked information about the intermediate animals. Tiktaalik neatly fills this morphological gap. It lets us see many of the individual steps and resolve the relative timing of this complex transition."

more:

http://www.sciencedaily.com/releases/2008/10/081015144123.htm


A new study of Tiktaalik roseae (middle), a 375-million-year-old transitional fossil, highlights an intermediate step between the condition in fish like Eusthenopteron (bottom) and that in early limbed forms like Acanthostega (top). (Credit: Kalliopi Monoyios)

Sorry -- couldn't help myself

McCan't must be an evolutionary throwback!

May I grab it please? It's Perfect!!! LOL

You should spread that one around.

and hunt on land, so what about them? Where do they fit in the evolutionary scheme of things?

My guess is that necks may have evolved and disappeared numerous times in fishes, just as bipedalism may have evolved and disappeared numerous times in primates, before it "caught on" and gradually led to us.

http://www.livescience.com/animals/060412_catfish_hunter.html

snip:

Having a mobile neck is key for hunting on land—it allows the catfish to move its head up and down to stab at prey. Mobile necks are a feature usually reserved for land animals called tetrapods.

Recent discoveries of early tetrapods, such as Ichthyostega and Tiktaalik, have revealed that these beasts had mobile necks, and Van Wassenbergh said his catfish study might provide insight to how these early land animals went after food.

(At the site there's a video showing an eel catfish catching a beetle on land.)

I think we are still evolving. I think that our brains are still evolving as each generation is maintaining more info than the previous generation.