June 5, 2013
The Late Jim ‘Lizard King’ Morrison Gets Giant Extinct Reptile Named After Him
Lawrence LeBlond for redOrbit.com - Your Universe Online
The late rocker Jim Morrison may have been known as “the Lizard King” during his heyday in the late-1960s, but another creature that lived 40 million years ago is being hailed as the “king of lizards.” The lizard, measuring some six feet long and weighing upwards of 60 pounds, was a giant plant-eating reptile that competed with mammals of the time in the hot tropical forests of Southeast Asia.
Perhaps it is only fitting then that these two “kings” of their time come together as one. In fact, this is what conclusion Jason Head of the University of Nebraska-Lincoln and his colleagues came to in a recent examination of one of the biggest known lizards to have ever lived on land. Publishing their work in the journal Proceedings of the Royal Society B, the team gave the lizard the name Barbaturex morrisoni.
It only seemed natural to Head to name the king of lizards after a man who became synonymous with lizards through his music and poetry.
Apart from the naming of the giant reptile, the team delved into the history of the beast, looking to see how a massive lizard thrived in an environment where it had to compete with mammals for food and other natural resources.
Modern plant-eating lizards such as iguanas and agamids are smaller than many of their mammalian herbivore competitors. Those that are larger and carnivorous such as the Komodo dragon are isolated on islands where mammalian competitors are practically non-existent. Head noted that currently it is not known if plant-eating lizards evolved to be smaller due to competition with mammals, or if temperatures of their habitats changed.
Unlike modern lizards, B. morrisoni thrived in an ecosystem that had a mix of herbivorous and carnivorous mammals during a warm period in Earth´s history, when there were no polar ice caps and carbon dioxide levels were much higher than they are today. And the lizard was larger than many of the mammals with which it competed against, suggesting to the researchers competition or predation by mammals didn´t restrict its evolution into a giant herbivore.
"We think the warm climate during that period of time allowed the evolution of a large body size and the ability of plant-eating lizards to successfully compete in mammal faunas," Head said. "You can't fully understand the evolution of ecosystems in the modern world without looking at the ones that preceded them. We would've never known this by looking at lizards today. By going back in time using the fossil record, we can find unique information on the origin of modern ecosystems."
Head worked with researchers from the University of California, University of Iowa and Duke University on the identification and analysis of B. morrisoni. The creature was discovered by Russell Ciochon of Iowa, one of the researchers in the new study, and colleagues in the 1970s in Myanmar. The fossilized remains went unstudied for decades, only to be re-discovered by Head and Patricia Holroyd a few years ago at the University of California Museum of Paleontology.
Upon initial analysis of the fossil, Head said he noticed the bones of the beast were characteristic of a group of modern lizards that include bearded dragons and chameleons and plant eaters such as the spiny-tailed lizards.
"I thought, 'That's neat. Based on its teeth, it's a plant-eating lizard from a time period and a place from which we don't have a lot of information.' But when I started studying its modern relatives, I realized just how big this lizard was. It struck me that we had something here that was quite large -- and unique," said Head.
Also, the ridges on the underside of the jaw strongly suggested it supported soft tissues, similar to the dewlaps (chin flaps) of modern bearded lizards; the genus name Barbaturex actually means “bearded king.”
Head said he had been listening to The Doors often during the research. “Some of their musical imagery includes reptiles and ancient places, and Jim Morrison was of course 'The Lizard King,' so it all kind of came together,” he explained.
Head said the discovery will now lead researchers to seek out answers to other questions surrounding B. morrisoni. Answers to questions like: “For how long do these giant lizards persist in the fossil record? How far and wide did they disperse across the planet? What are the relationships of the evolution of reptile body sizes to changes in global temperature throughout history? And the obvious question -- does a warming climate mean giant reptiles will someday return?”
Head said that if the global temperature was to rise at a natural pace and preserve natural, healthy habitats, lizards could potentially evolve into giants once again, as well could turtles, snakes and crocodiles.
"But we're changing the atmosphere so fast that the rate of climate change is probably faster than most biological systems can adapt to. So instead of seeing the growth and spread of giant reptiles, what you might see is extinction," he said.
He added that researchers will likely consider how the evidence so far can be used to reconstruct global temperature over geologic time scales. "That becomes very important in modeling what temperature change will be like across the surface of the planet in the future. And that, obviously, bears directly on our own health,” he concluded.