[News] 3D Renderings show first land animals 'could not have walked'

[Livewire]

http://www.bbc.co.uk/news/science-environment-18177493

One of the first creatures to step on land could not have walked on four legs, 3D computer models show.

Textbook pictures of the 360-million-year-old animal moving like a salamander are incorrect, say scientists.

Instead, it would have hauled itself from the water using its front limbs as crutches, research in Nature suggests.

The move from living in water to life on land - a pivotal moment in evolution - must have been a gradual one.

Ichthyostega is something of an icon in the fossil world. Living during the Upper Devonian period, it was dubbed a "fishapod", with its mixture of fish-like and amphibious features.

"Our reconstruction demonstrates that the old idea, often seen in popular books and museum displays, of Ichthyostega looking and walking like a large salamander, with four sturdy legs, is incorrect”

-Prof Jenny Clack University of Cambridge

Although it probably spent much of its time under water, at times it was thought to have crawled halfway up onto land on limb-like flippers.

Exactly how it moved on land has been a matter of much debate, however.

Now, a team from The Royal Veterinary College, London and the University of Cambridge, has spent three years reconstructing the first 3D computer model of Ichthyostega from fossils.

It enabled them to study how ancient vertebrates made the "monumental transition" from swimming to walking.

Study author Dr Stephanie Pierce, of The Royal Veterinary College, said the 3D skeleton allowed them to calculate the range of movement in the joints of its limbs for the first time.

The research suggests the animal shuffled on land using hind limb movements similar to that seen in seals rather than moving its limbs in the familiar walking pattern seen today.

Dr Pierce told BBC News: "We're almost bringing the animal back to life by doing this.

"What we've discovered is that some early tetrapods definitely did not have the ability to walk on land. We at this stage are not actually sure which animals - or group of animals - were the first to do this."

Co-author Prof Jenny Clack from the University of Cambridge added: "Our reconstruction demonstrates that the old idea, often seen in popular books and museum displays, of Ichthyostega looking and walking like a large salamander, with four sturdy legs, is incorrect."
Fundamental question

Commenting on the study, Dr Susannah Maidment of London's Natural History Museum, said understanding where we came from, or where all the things that live on the land came from, is one of the most fundamental questions.

"What this study suggests is that this animal, which has been traditionally thought of as the first four legged animal to walk on land wasn't walking on land at all.

"It sends us almost back to the drawing board...I guess it even sends you back to the field to look for more fossils."

The research, reported in a paper in Nature, was funded by the Natural Environment Research Council.

I thought this was pretty interesting myself. Thoughts?

inb4 Evolution deniers

[TRIFORCE89]

Makes sense to me. I always thought the first land animals would be kinda... seal / sea lion -like for limbs.

Like whales have "fingers" when you look at the flipper in their skeletons.

[Shiny Bidoof]

Seems like common sense. Evolution didn't make fish pop out legs and go walking around. The legs have to start as something else first.

[Went]

I think the only people who think fish would have become dogs of a sudden are people who don't understand evolution at all ("popular books" and some "museum displays"). Obviously you can't move straight from swimming to walking on four legs in a fortnight, and we all know there are several steps in between, such as snakes and other reptilians which fit the description of "land animals which don't walk on four legs" to a T.

It's good to have a confirmation anyway.

[Shiny Bidoof]

Originally Posted by Went

we all know there are several steps in between

I remember when I took an anthropology class and realized that I barely even knew how evolution worked. It's a very complex and messy process with dead ends and loosely defined "species." I wouldn't even describe it as "steps," because it sounds too clean, like it's a straight line.

Anyway, evolution is some very cool stuff. It really changes the way you see the world.

[outfox]

Originally Posted by Shiny Bidoof

Anyway, evolution is some very cool stuff.

Isn't it incredible? Not just in creatures, either, in everything.

"[mountains] grow barely perceptively, the product of thousands of tiny rises... over the aeons. Time, unimaginable time, that was the key; given it, anything could be achieved.

Darwin now understood. He plotted the quake's epicenter and pinned down its cause to incipient volcanic action. Hot springs and 'bubbles of gas & discoloured water' percolating into the sea proved beyond doubt that 'the earth is a mere crust over a fluid melted mass of rock.

from Darwin: The Life of a Tormented Evolutionist by Adrian Desmond and James Moore

Life is beautiful.

[Yuoaman]

Wait, you mean you're steps are supposed to take you in a straight line? I HAVE BEEN LIVING A LIE.

It's always interesting to see our understanding of our own origins grow in any way, however.