Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Four-legged fish an evolutionary mistake


The ”four-legged fish” Ichthyostega is not the ”missing link” between marine and land animals, but rather one of several short-lived ”experiments”. This is what scientists from Uppsala and Cambridge universities maintain in an article in the latest issue of the scientific journal Nature.

The ”four-legged fish” Ichthyostega lived in Greenland during the Devon Period, some 355 million years ago, and is one of the very oldest land vertebrates. Since it was discovered back in the 1930s, and nearly the entire skeleton has been preserved, it quickly acquired iconic status as the ”missing link” between fish and land animals. Now a Swedish-British research team is presenting a new reconstruction of this classic animal that paints a radically different picture of its body shape and life style.

It isn´t easy to interpret the fossil of Ichthyostega. Even though almost the whole skeleton is represented, there is no single fossil that shows the whole animal. Instead it is necessary to assemble a puzzle from information found in several different fossils. This was first done in the 1950s by Professor Erik Jarvik at the Museum of Natural History in Stockholm, who reconstructed the animal with a crocodile-like body standing on four sturdy legs, with a large torso and a simple backbone made up of identical vertebrae. However, for the last five years a research team from Uppsala and Cambridge has been piecing together another interpretation.

- We discovered that the vertebrae are not at all identical, but differ depending on where in the body they were located. Moreover, the torso is differently shaped than Jarvik thought, and the hind legs look more like the flippers of a seal, says Professor Per Ahlberg of Uppsala University.

The new reconstruction assigns Ichthyostega a backbone that resembles that of a mammal-surprising for such an early land animal. This means that Ichthyostega had an unusual pattern of locomotion. Both fish and primitive now-living land animals, such as salamanders and lizards, move by slithering their bodies sideways. This also seems to be the case for Acanthostega, the other (and more primitive) four-legged fish from Greenland in the Devon Period. But Ichthyostega‚s large torso, with ribs that overlap like roofing tiles, made its upper body completely stiff, and the hind quarters seem rather to be adapted to flexing vertically, as in mammals.

- Ichthyostega probably moved rather clumsily on land by lifting its upper body and ”walking” on its front legs while simultaneously floundering along on its hind flippers. Its also possible that it combined with this a vertical bending of the spine to slide forward something like a giant inchworm, says Per Ahlberg, who maintains that Ichthyostega is not the ”missing link” but rather one of several short-lived evolutionary experiments with various bodily shapes and patterns of locomotion during the transitional period from marine to land life.

Anneli Waara | alfa
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>