The dime-sized chameleon is 78 million years older than the previous specimen on record, and it, along with 11 more amber encased lizards were harvested from a mine in Myanmar several decades ago, Phys.org reports. But only recently have scientists had the chance to analyze them.
These remarkable fossils give scientists clues to the “missing links” in the evolutionary history of lizards, and this will help scientists to better understand where they fit on the tree of life, said Edward Stanley, a University of Florida postdoctoral student in herpetology at the Florida Museum of Natural History.
In particular, three specimens were very well preserved — a gecko, an archaic lizard, and the chameleon. These and the other fossil lizards are described in a paper published in Science Advances on Friday, The Washington Post reports.
Stanley, a co-author of the study, discovered the fossils at the American Museum of Natural History, in New York after a private collector made them available for study. Based on the mine where they were discovered in Myanmar, they were dated back to Mid-Cretaceous Period, some 100 million years ago. By using 3-D scanning techniques to reconstruct the little reptiles, Stanley and his colleagues soon realized just how special these fossils were.
“The fossilized amber provides a view into a lost world, revealing that the tropics of the Mid-Cretaceous contained a diverse lizard fauna,” Stanley said, according to BBC News.
The tiny chameleon appears to be a transitional form between the “standard” lizard form and modern chameleons, he said, noting “that features like the chameleon’s projectile tongue was present deep in its ancestry.”
“But its strange fused toes (adaptations for climbing along branches) evolved later.”
The fossils provide scientists with something that’s pretty rare to find — external morphology, said Juan Diego Daza of Sam Houston State University in Texas, who led the research.
“These fossils represent most of the diversity of lizards with a superb amount of detail,” he noted.
And amber can preserve soft tissues, internal organs, and bones for millions of years.
“We can pretty much see how the animals looked when they were alive,” Daza said. “They provide a really nice snapshot of the past. To me it is like going back in time and doing a lizard collecting trip when we cans see what these animals looked like.”
But even so, the lizards were extremely tiny and delicate, with some of them less than an inch long, and many of these crucial pieces of the evolutionary puzzle were lost to decay, The Washington Post reports.
With their fragile bones and delicate skin, small lizards don’t preserve well, especially in the tropics, Stanley wrote in a statement. This is what makes these amber fossils important; they are a rare window into a crucial period of diversification.
In the case of the gecko in amber, the fossil shows that this group had highly advanced adhesive toe pads, which are used for climbing, and this suggests it’s an adaptation that originated earlier, Phys.org notes. Modern geckos have these toe pads and they are excellent climbers.
Ultimately, the fact that these ancient lizards have modern counterparts living in the Old World tropics today is testament to the stability of tropical forests, Stanley said.
“These exquisitely preserved examples of past diversity show us why we should be protecting these areas where their modern relatives live today,” he said. “The tropics often act as a stable refuge where biodiversity tends to accumulate, while other places are more variable in terms of climate and species. However, the tropics are not impervious to human efforts to destroy them.”
Indeed, the world’s tropical rain forests are vanishing at a depressing rate. UNESCO notes that in the last 50 years 50 percent of the earth’s rain forests have been destroyed. And the current rate of destruction is rapacious, with an area of rain forest that’s the size of 2,000 football pitches being plundered during a 90 minute football match.
Rain forests are vanishing for agriculture and settlements for the endlessly growing human population, and for cattle ranching, especially in central and South America, UNESCO reports. Logging for hardwoods, fuel, building materials, and pulp for paper, road construction for access to mines, dams, and settlements are also contributing to the devastation. Much of Amazonia is being plundered in mining for bauxite, oil, gold, diamonds, and iron ore, while in Indonesia mining for nickel, copper, tin, and coal is one of the main causes of deforestation. In Colombia and Brazil, mining for coal, uranium, and gold are also devastating rain forests.
With the loss of the world’s rain forests, all this remarkable diversity, not just in reptiles, but in insects, birds, and mammals will disappear, perhaps over time producing lots of fossils on this devastated planet.
Note: The video below shows the exquisite details of these fossils in 3D.
