New study refutes 75-year-old belief in reptile evolution

Challenging the 75-year-old notion of how and when reptiles evolved over the past 300 million plus years involves lots of camerawork, loads of CT scanning, and most of all, thousands of miles of travel. Just check the stamps in Tiago R. Simiz’s passport.

Alexander Agassi is a postdoctoral fellow in the lab of Simis Harvard paleontologist Stephanie Pierce. From 2013 to 2018, he traveled to more than 20 countries and more than 50 different museums to take CT scans and photos of nearly 1,000 reptiles that are nearly a million years old. It is the amount of active collection of about 400 days, which is considered to be the largest available timeline on the evolution of major living and extinct reptile groups.

Now, a statistical analysis of that vast database helps scientists better understand the evolution of these cold-blooded spines that large-scale change always occurs in large, rapid (geographically speaking) explosions, triggered by large environmental migrations. . The findings are described in a recently published paper in Nature Communications.

In it, researchers show that the evolution of the extinct lineage of reptiles 250 million years ago. During a period of 50 million years many small explosions of morphological changes such as the development of arms body plans or the development of wings for gliding. During a big evolving event, which was previously thought. They also show that the early evolution of most lizard lineages was a process of continuous slower and greater growth than previously understood.

“It wasn’t the sudden jump that established the kind of diversity we’re seeing in reptiles today.” “There was an initial jump, but it was relatively small, and then that rate continued to rise over a period of time [of evolution] And different variation values. “

Evidence of this has been seen in other types of animals, but this is the first time it has been seen in a reptile, one of the most diverse animals on the planet, with more than 10,000 different species and a variety of abilities and qualities. Consider how some lizard species can solidify overnight and then melt the next morning, or how turtles grow protective armor.

Harvard paleontologist George G. in the 1940s. Simpson, who tried to explain the origin of the planet’s biodiversity, has found the opposite of the evolutionary theory of adaptive radiation. Adaptive radiation has been the subject of intense research for many decades, but until recent years the technology, methods, and data have not existed, accurately measuring the rapid rate of evolution in various animal species, morphologies, and fossil records. At the molecular level using DNA.

The researchers of this study, Pierce, Thomas d. Cabot Organ also included an associate professor of organizational and evolutionary biology and curator of vertebrate paleonology at the comparative zoo; Orsana Vernigora, a graduate student from the University of Alberta, Canada; And Professor Michael Wayne Caldwell of Alberta.

Simis traveled to almost all the major natural history museums in the world to collect data for the study, including the National Natural History Museums in London, Paris, Berlin, Ottawa, Beijing and Tokyo. U.S. In, he visited the Smithsonian National Museum of Natural History, the Carnegie Museum of Natural History and the Harvard Museum of Cooperative Zoology.

Scientists believe that by understanding how animals evolve over a long period of time, they can collect many lessons on ecology and how environmental changes affect organisms. Using the database, researchers can determine when major reptile lineages or morphologies originated, how those changes affect reptile DNA, and learn important lessons about how species have been affected by historical events.

Reptiles, for example, have survived three mass extinctions. The extinction of the Permian-Triassic mass about 250 million years ago was what killed about 90 percent of the planet’s species, and it earned the moniker Great Dyeing. It is believed that this is due to the formation of natural greenhouse gases.

Researchers who created the timeline found that the rates at which reptiles were developing before the Great Dyeing and the anatomical differences between them were as high as after the event. However, it was only after the Great Death that reptiles became dominant in many ecosystems and are extremely diverse in terms of the number of different species.

It was discovered that rapid rates of body mutations are called genetic diversity or technological diversity, and that adaptive radiation does not need to be adapted as the only explanation for the origin of new animal groups and body schemes. Researchers have also noted that it took reptiles about 10 million years to recover the previous levels of anatomical diversity.

“A comprehensive plan of these kinds of things and globally tells you how much impact sudden environmental change can have on the entire history of life,” Simis said.

There is further evidence that paradoxical adaptive radiation contains similar but surprising findings about the origins of snakes, which achieved key aspects of their skinny, elaborate body plans about 170 million years ago at the beginning of their evolution (but did not completely lose their limbs for the other 105). Years). They made rapid changes to their skulls about 170 to 165 million years ago which led to such powerful and flexible muscles that today they can swallow their prey in many sizes. While snakes have experienced the fastest rates of anatomical change in the history of reptile evolution, these changes are not consistent with the increase in taxonomic diversity or the rate of atomic evolution as predicted by adaptive radiation, the researchers said.

Scientists have not been able to pinpoint why this misunderstanding occurs, and suggest that more research is needed. In particular they want to understand how the body plans to evolve and how changes in DNA are related to it.

“We can now better see what big changes have been made in the history of life and especially in the history of reptile life on Earth,” Simis said. “We’ll keep digging.”