Amateur fossil hunter Van Turner felt certain he had found something important during his search of earth turned up by bulldozers making way for a new subdivision in Dallas County.

Sixteen years later, scientists finally confirmed that Turner had discovered the first well preserved early mosasaur found in North America — a prehistoric lizard that lived 92 million years ago that evolved into what some call the "T. Rex of the ocean."

"Science marches slowly, and my biggest fear all along has been that another specimen of the same animal would be found, and it would be described, and I would lose any first claim to it," said Turner, an Internet technology manager in the Central Texas town of Mason. "That never happened, and it kind of reassured the rarity of the animal."

The reptile, now known as Dallasaurus turneri, is identified in a special issue of the Netherlands Journal of Geosciences published this month. The article was written by paleontologists Michael Polcyn of Southern Methodist University and Gordon Bell Jr. of Guadalupe National Park.

The lizard is an important link in the evolution of mosasaurs, which lived in the age of dinosaurs and evolved fin-like limbs, Polcyn said.

Dallasaurus, the name given the fossil by Polcyn and Bell, is unusual because it shows an earlier version of the mosasaur with tiny feet and hands. The marine animals later developed paddles.

Before this discovery, only five primitive forms of the animal with land-capable limbs were known, and all of them were found over the last century in the Middle East and the eastern Adriatic, Polcyn said.

"This is exciting to us. It tells us the origin of mosasaurs," said Anthony R. Fiorillo, curator of earth sciences at the Dallas Museum of Natural History, which displays a much larger reconstructed mosasaur with sharp teeth and a massive jaw.

On Wednesday, the museum unveiled a model of Dallasaurus, not nearly as threatening as its oversized descendant with a slim body and only 3 feet of length. It looks somewhat like a Komodo dragon, its closest living relative.

"I call him Todd," said Ross McMillan, the ponytailed sculptor who worked with Polcyn for months to painstakingly construct the lifelike piece. "When you look at his face, doesn't he look like a Todd?"

Fiorillo and Polcyn said Turner's find, made at Cedar Hill south of Dallas, highlights the importance of contributions made by amateur fossil hunters to science.

"This just goes to show you that what you want is a lot of people looking for stuff," Turner said. "You want them to be able to recognize important finds or have the people who can do it."

Scientists and museum curators hope to reconstruct the more than 100 identifiable skeletal pieces that make up Dallasaurus and put them on display within a few years at the Dallas museum, which owns them.

Right now, the skeletal pieces, comprising about 80 percent of the animal, are being kept at SMU for study. A similar specimen, also acquired and donated by Turner, is at the Texas Memorial Museum at the University of Texas at Austin.

Mosasaurs lived in the shallow seas and shores of a stretch of Texas around Dallas and Fort Worth that was mostly under water back then, Polcyn said. The animals evolved into the top predator of their domain before becoming extinct 65 million years ago.

The lizard is not related to the 13-foot oceanic crocodile discovered recently in Argentina, Polcyn said. The discovery of that creature, given the scientific name Dakosaurus andiniensis and nicknamed "Godzilla," was reported last week in ScienceExpress, the online edition of the journal Science.