Named Dallasaurus for where it was found, part of a line of land
dwelling lizards that became aquatic. The line eventually evolved into
the mosasaurs.

I'm waiting for some wiseguy/gal to make some comment about a now
extinct TV show.


---
SMU and Dallas Museum of Natural History
Announce Missing Fossil Link Dallasaurus

(DALLAS) When amateur fossil finder Van Turner discovered a small
vertebra at a construction site near Dallas 16 years ago, he knew the
creature was unlike anything in the fossil record. Scientists now know
the significance of Turners fossil as the origin of an extinct line of
lizards with an evolutionary twist: a land-dwelling species that became
fully aquatic.

Named Dallasaurus for where it was found, part of a line of land
dwelling lizards that became aquatic. The line eventually evolved into
the mosasaurs.

I'm waiting for some wiseguy/gal to make some comment about a now
extinct TV show.

Named Dallasaurus for where it was found, part of a line of land
dwelling lizards that became aquatic. The line eventually evolved into
the mosasaurs.

I'm waiting for some wiseguy/gal to make some comment about a now
extinct TV show.


---
SMU and Dallas Museum of Natural History
Announce Missing Fossil Link Dallasaurus

(DALLAS) When amateur fossil finder Van Turner discovered a small
vertebra at a construction site near Dallas 16 years ago, he knew the
creature was unlike anything in the fossil record. Scientists now know
the significance of Turners fossil as the origin of an extinct line of
lizards with an evolutionary twist: a land-dwelling species that became
fully aquatic.

Turner took the remains to paleontologists at the Dallas Museum of
Natural History, but it took several years before scientists dubbed the
find Dallasaurus turneri. Word of Dallasaurus is now reaching the
scientific community with a special issue of the Netherlands Journal of
Geosciences, featuring an article by Southern Methodist University
paleontologist Michael Polcyn and Gordon Bell Jr. of Guadalupe National
Park in Texas.

They describe Dallasaurus, a three-foot long lizard who lived 92 million
years ago in the shallow seas and shores of what was then a stretch of
Texas mostly under water, and also used the fossil to better understand
the mosasaur family tree. Polcyn and Bell painstakingly pieced together
an understanding of the anatomy and natural history of Dallasaurus from
the bones Turner discovered and from some matching skeletal remains at
the Texas Memorial Museum at the University of Texas in Austin.

Dallasaurus represents a missing link in the evolution of a group of
creatures called mosasaurs, prehistoric animals that started out on
land, but evolved in the seas and dominated the oceans at the same time
dinosaurs ruled the land. One aspect of Polcyn and Bells research is the
revelation that Dallasaurus retained complete limbs, hands and feet
suitable for walking on land, whereas later mosasaurs evolved their
limbs into flippers.

This is pretty close to the beginning of the mosasaur family tree, says
Dallas Museum of Natural History Earth Sciences Curator and SMU Adjunct
Professor of Paleontology Anthony R. Fiorillo, Ph.D. It is the most
complete mosasaur retaining all of its limbs found in North America.

Mosasaurs, every bit as prolific, fascinating and nearly as big as some
dinosaurs, are becoming more popular for paleontologists to study.
Mosasaurs lived and became extinct alongside dinosaurs, but few
paleontologists specialize in them. Later mosasaurs grew as large as
their dinosaur brethren, reaching up to 45 feet in length. Until the
discovery of Dallasaurus, however, only five primitive forms with
land-capable limbs were known, all of them found in the Middle East and
the eastern Adriatic.

Lizards had nearly 150 million-year-long history on land; then in the
Late Cretaceous, the final stage of the age of dinosaurs, one group
moved into the sea and rose to the very top of the food chain, explains
Polcyn, director of SMUs Visualization Laboratory, part of the
universitys geological sciences department. Starting out as small
animals like Dallasaurus, they mastered their new marine environment and
rose to become the top predator in their ecosystem, the T. Rex of the
ocean.

The Late Cretaceous period was a time of hot house temperatures and
rising sea levels.

As the earth warmed and the seas rose, small land-dwelling lizards took
to the oceans and developed increasing levels of seagoing capabilities,
and over 30 million years, eventually evolving into the top predator of
their domain before becoming extinct some 65 million years ago says
Polcyn.

The advanced fin-bearing mosasaurs have been grouped into three major
lineages. Although a small number of primitive mosasaur have been known
to retain land-capable limbs, they were thought to be an ancestral group
separate from the later fin-bearing forms. Dallasaurus represents a
clear link to one lineage of the later forms and the first time
researchers can clearly show mosasaurs evolved fins from limbs within
the different lineages of mosasaurs.

With the aid of computer science and SMUs visualization laboratory,
Polcyn has been able to simulate what Dallasaurus looked like, and how,
based on his skeletal remains, he would swim and move from land to sea.
An artist has taken Polcyns visualization work even one step further by
creating a life-sized model of Dallasaurus, a work that is soon to be on
display at the Museum along with the computer simulation.

When funds become available for reconstructing a suitable exhibit, the
bones of Dallasaurus will be displayed at the Dallas Museum of Natural
History. The work, however, will take several more years of additional
efforts and substantial funding. A nearly 30-foot long mosasaur, some 75
million years old, already is on display at the Dallas Museum.

Major dinosaur finds are frequently the result of creatures dying in
groups through flooding or drought, situations that lend themselves
fairly well to more complete preservation and conservation of their
bones, and much slower deterioration. Mosasaur fossils, in contrast, are
rarely found in large groupings, and are only found in areas once
covered by seas. Remains were quick to deteriorate under ocean currents;
their bodies often fell victim to the ravages of other sea life, such as
sharks, who would pick away at carcasses for food. Because of their
mostly shallow sea and seaside habitats, the remains of early mosasaurs
are even more rare and much harder to find.

But in the last two decades, many new discoveries and significant
advances have been made in the understanding of mosasaur evolution and
how they lived. Dallasaurus significantly advances that understanding by
filling in a long missing piece of mosasaur evolution, specifically a
time at which they transition from land to sea.

The importance of Turners discovery isnt lost on the researchers putting
together the pieces of the mosasaur puzzle. In fact, they predict the
legacy of Turners discovery will live on. His contribution was honored
by naming the species, turneri, after his last name. Not all major
discoveries are made by highly trained paleontologists, notes Dallas
Natural History Museum Curator Fiorillo. The observant individual, even
kids, can still make an important find, he says. Once this goes
mainstream, and people begin to recognize what mosasaurs are, well be
finding more and more.