Fossil from most primitive 4-legged creature found

[SolInvictusMithras]

The Schenectady Gazette
By Seth Borenstein
The Associated Press

WASHINGTON -- Scientists unearthed a skull of the most primitive four-legged creature in Earth's history, which should help them better understand the evolution of fish to advanced animals that walk on land.

The 365 million-year old fossil skull, shoulders and part of the pelvis of the water-dweller, Ventastega curonica, were found in Latvia, researchers report in a study published in today's issue of the journal Nature.  Even though Ventastega is likely an evolutionary dead end, the finding sheds new details on the evolutionary transition from fish to tetrapods.  Tetrapods are animals with four limbs and include such descendants as amphibians, birds and mammals.

While an earlier discovery found a slightly older animal was more fish than tetrapod, Ventastega is more tetrapod than fish.  The fierce-looking creature probably swam through shallow brackish waters, measured about three or four feet long and ate other fish.  It likely had stubby limbs with an unknown number of digits, scientists said.

"If you saw it from a distance, it would look like a small alligator, but if you look closer, you would find a fin on the back," said lead author Per Ahlberg, a professor of evolutionary biology at Uppsala University in Sweden.

This all happened more than 100 million years before the first dinosaurs roamed the earth.

[Evolved]

Cool looking creature.  It reminds me of a coelacanth.



Welcome to the forum, SolInvictusMithras.  Can I call you Sol?

[curiosityandthecat]

Sauce?

...er, I mean, link to the source article?

[SolInvictusMithras]

Sauce?

...er, I mean, link to the source article?

This was reported in a local newspaper, not online, so I'm afraid I don't have a link to share.  I received the article as a clipping, but I'll try to find out what page it was originally on etc.

EDIT: I found out from the person who gave me the clipping that this was reported June 26th on page A2 of the Schenectady Daily Gazette.  Many thanks to crocofish for the news.google links in the meantime.

[SolInvictusMithras]

Cool looking creature.  It reminds me of a coelacanth.



Welcome to the forum, SolInvictusMithras.  Can I call you Sol?

Yes, you may.  Nice to meet you and nice to be here.

[crocofish]

While an earlier discovery found a slightly older animal was more fish than tetrapod, Ventastega is more tetrapod than fish.

I assume the "slightly older animal" is Tiktaalik, which happens to be my avatar.  Tiktaalik was from about 375 million years ago.  It's not surprising that there would many different lifeforms in the spectrum between fish to amphibians to reptiles.

news.google.com hits on lots of links for Ventastega.

[Loffler]

Evolutionary questions: why do modern fish have scales, and modern reptiles have scales, but modern amphibians have skin? Did they lose scales or did fish and reptiles gain them?

Or are modern amphibians not truly descended from the "amphibious species" that brought fish to the land?

[crocofish]

Evolutionary questions: why do modern fish have scales, and modern reptiles have scales, but modern amphibians have skin?

It appears that amphibians and reptiles branched off from a common tetrapod ancestor, as seen in this simplified tree from a Wikipedia article.  Reptiles didn't descend directly from amphibians.  Amniotes are the group of animals that includes reptiles, birds, and mammals, based on embryonic development.  Amphibians and fish are not amniotes.  

Code Select Expand

--Tetrapods--------------------------------------------------
      |
      +-- Amphibians ---------------------------------------
      |
      `--Amniotes-----
             |
             +--Sauropsids------------------------------------
             |
             `--Synapsids------
                    |
                    `--Pelycosaurs----
                           |
                           `--Therapsids-----
                                  |
                                  `--Mammals------------------

What makes the early tetrapods so interesting is that they are the common ancestors to all land animals (not including insects).  They were the pioneers that ventured out of the water and led to all the reptiles, birds, and mammals, including us.

[Kylyssa]

There are also fish that do not have scales such as puffers and dragonets.  Hair, feathers, scales - it's fascinating how similar they all are.