Tiktaalik roseae

 
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Tiktaalik roseae

During a time in Earth’s history known as the Devonian period, which occurred from 358 to 419 million years ago, land masses that currently make up the Arctic were located just south of the equator. This was due to continental drifting, resulting in a tropical climate.

Image: The fossilized remains of Tiktaalik roseae.

 
3D View: Tiktaalik roseae
 
 
One reconstruction and one fossil of Tiktaalik roseae.

Why this species is important

One creature that lived during this time period was a creature known as Tiktaalik roseae (its scientific name).  Paleontologists refer to this creature as the missing link.  Tiktaalik roseae evolved to have some physical features similar to fish and other features similar to land-based, four-legged, vertebrates.  This fossil is referred to as the transitional link as it is a good indicator of when fish first began evolving into land animals.

 

The Continental Drift

The Earth is constantly changing.  Over millions of years the planet's continents have shifted and continue to do so today.  This geological phenomenon is known as the Continental Drift.

Associated with these drifts are specific geological time periods when air temperature and life on Earth was very different than present day.

This interactive image shows how the Earth's continents have shifted over millions of years.  400 million years ago the Earth's land masses were close to one another and near the equator.  Around every 100 million years there were major landmass shifts. By 10 million years ago, the Earth's continents were located in their current positions.

A map of the world showing the continents shifting between 400 and 10 million years ago.
 
10 million years ago
400 million years ago
 
 

A four-legged fish

 

Tiktaalik roseae has been nicknamed ‘fishapod’.  After scientists had studied this fossil they found that the species had physical traits associated with both fish and four limbed vertebrates, also known as tetrapods. Its fish characteristics include the existence of scales, fins and gills while its tetrapod characteristics include ribs, a neck and lungs.

 

 

A new discovery

 

Tiktaalik roseae was discovered in 2004 on Ellesmere Island, Nunavut and lived in that region 375 million years ago.

 

The meaning of a name

 

Tiktaalik roseae is the Inukitut name meaning “burbot,” a cod-like freshwater fish.

 

Video

 

A palaeontological discovery

Watch this video describing the discovery of Tiktaalik roseae.

 

Transcript: A palaeontological discovery

Narrator:
Paleontologists have discovered the complete fossilized remains of a new species that marks some fish first walked out of the waters onto land 375 millions years ago. According to the University of Chicago's, Neil Shubin, co-leader of the Arctic expedition that found the missing evolutionary link, tiktaalik is the most compelling example, yet, of an animal that was at the cusp of the fish tetrapod transition.

Neil Shubin
University of Chicago:
It is a fish that blurs the distinction between a fish and a land-living animal. It looks like a fish and it has scales and fins, but when you look inside its skeleton you see how special it really is. It has inside its fins a wristed, finger-like structure. What is this telling us? It's telling us that this is a fish that can live in the shallows or even make short excursions onto land.

Narrator:
As described in two linked researched articles highlighted on the cover of the April issue of Nature, Tiktaalik was a predator with sharp teeth, a crocodile-like head and flattened body, while maintaining fish-like features such as scales, fins and a primitive jaw.

Neil Shubin:
Now what is really important here is that we are not just dealing with some aberrant or crazy group of fish. What we are dealing with here are pieces of our own bodies. This is not just some archaic weird branch of evolution. This is our branch of evolution.

Narrator:
The discovery has other implications as well. It offers the team and future researchers new context in the search for more species to complete the story of evolution on Earth.
This is Renee Basick.

“Tiktaalik Roseae: Bridging the Evolutionary Gap Between Fish and Land Animals”
VO Talent: Renee Basick
Produced by: The Chicago Media Initiatives Group
©The University of Chicago

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