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Fossil Provides More Insight into Water-to-Land Evolution
June 26, 2008 05:00 PM
by
Liz Colville
In Latvia, scientists have uncovered the fossil remains of Ventastega, a creature with a fishlike body, four flippers and a land-adapted head.
30-Second Summary
The fossil remains of a creature known as Ventastega curonica were discovered in Latvia. Professors of Uppsala University, Sweden, published their findings about the discovery in Nature. The creature’s head was that of a land animal, while its body retained characteristics that made it “habitually aquatic,” writes the BBC.
Ventastega, like the Tiktaalik (“walking fish”) discovered in Canada in 2004, is a transitional link between fish and land mammals. Ventastega, which existed approximately 365 million years ago, is a later but more primitive species.
Lead author Per Ahlberg told the BBC that from a distance, Ventastega “would have looked like an alligator. But closer up, you would have noticed a real tail fin at the back end, a gill flap at the side of the head; also lines of pores snaking across head and body.”
The published research is one of several recent studies of transitional animals.
A recently published map of the platypus genome has also provided various insights into mammalian evolution.
Ventastega, like the Tiktaalik (“walking fish”) discovered in Canada in 2004, is a transitional link between fish and land mammals. Ventastega, which existed approximately 365 million years ago, is a later but more primitive species.
Lead author Per Ahlberg told the BBC that from a distance, Ventastega “would have looked like an alligator. But closer up, you would have noticed a real tail fin at the back end, a gill flap at the side of the head; also lines of pores snaking across head and body.”
The published research is one of several recent studies of transitional animals.
A recently published map of the platypus genome has also provided various insights into mammalian evolution.
Headline Link: ‘Fossil fills out water-land leap’
The Ventastega is thought to have inhabited the “shallow waters and tidal estuaries” of Latvia, approximately 100 million years before dinosaurs came into existence. A surprising attribute of the creature, the professors found, is its limbs. “These were little things sticking out of the sides, with a strangely high number of digits. You would have seven, eight, maybe even nine toes per foot.”
Source: The BBC
Background: Fish with feet
The fossil remains of Tiktaalik roseae, found in the Canadian Arctic, “changed the way we think about the organs of life on land,” according to the University of Chicago online project devoted to the animal. The creature’s “special mix of features” include a flat head and body “with eyes on the top of its skull, more like a crocodile than most fish. Its shoulders are not connected to its skull, giving it a functional neck … And it has ribs like some of the earliest tetrapods.”
Source: University of Chicago
In a Scientific American article, Jennifer A. Clack explains the importance of the water-to-land transition and what recent findings like Tiktaalik tell us about our ancestors. In 2005, Clack, Per Ahlberg and Henning Blom published their research about Ichthyostega, another important transitional animal that demonstrated “some adaptations for nonswimming locomotion.” But creatures like Ichthyosteag, Ventastega and Tiktaalik were inevitably doomed by their “body plans.”
Source: Scientific American
An arm bone excavated in Pennsylvania in 2001 is another clue to the water-to-land story, providing more evidence that transitional creatures lived in what is now the United States. The design of the bone suggested it could support a “pushup” movement, an “intermediate condition between primitive steering and braking functions in fins and the derived aquatic or terrestrial walking gait.”
Source: University of Chicago Chronicle
Related Topic: Scientists study platypus genome
The unique duck-billed platypus—“part bird, part reptile and part lactating mammal”—has mystified scientists for over a century, and studying its genetic makeup has proved useful to understanding human evolution. Oxford University’s Chris Ponting, who led a team of researchers in the sequencing of the creature’s genome, called the platypus “the missing link in our understanding of how we and other mammals first evolved.”
Source: findingDulcinea
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