Scientists study early and late mosasaurs

The ancient lizard, named Dallasaurus turneri, measured three feet long and lived 92 million years ago in shallow seas that covered what is now Texas, National Geographic News reported.

Researchers say Dallasaurus is unusual because it had tiny feet and hands used for walking on land. Later mosasaurs developed fin-like limbs and eventually dominated the seas at the time when dinosaurs ruled the land.

"This study paints a much more complex picture of the evolution of (mosasaurs) than previously thought," said Michael Polcyn, a paleontologist at Southern Methodist University in Dallas.

The later mosasaurs grew as large as their dinosaur brethren, some reaching up to 45 feet in length, National Geographic News said. The Dallasaurus lineage later produced the prognathodon, a fearsome marine reptile that Polcyn calls "the T. Rex of the sea."

Polcyn led the research, which is reported this month in the Netherlands Journal of Geosciences.

Copyright 2005 by United Press International