A specimen stored away in a storeroom has finally had its identity confirmed, changing our understanding of when modern lizards originated by millions of years.
A specimen stored away in a storeroom has finally had its identity confirmed, changing our understanding of when modern lizards originated by millions of years.
This tiny skeleton, found within rocks dating back to the Triassic period in a quarry close to Bristol, is over 205 million years old and is recognized as the oldest known modern-style lizard.
Recently, the findings from the University of Bristol team faced skepticism, but a new analysis was published today in Royal Society Open Science, demonstrating the fossil’s relationship to contemporary anguimorphs like anguids and monitors. This groundbreaking discovery pushes the timeline for the origin of the entire lizard-snake group, known as Squamata, back by 35 million years.
In their initial study, Dr. David Whiteside, Dr. Sofia Chambi-Trowell, and Professor Mike Benton introduced the tiny creature as Cryptovaranoides microlanius, meaning ‘hidden lizard, small butcher,’ due to its identification as a lizard and its sharp teeth, which likely served to tear apart prey. The Bristol team highlighted numerous features in the skull and skeleton that helped them classify it firmly within Squamata and close to the Anguimorpha group.
“We anticipated that our paper would spark debate,” said Dr. Whiteside. “However, we were confident that we had meticulously examined every possible characteristic and compared it with all known data.”
Professor Benton expressed his surprise: “We were quite taken aback, perhaps even shocked, when in 2023, another group of researchers proposed that Cryptovaranoides was neither a lizard nor a close relative, but instead an archosauromorph, more akin to crocodiles and dinosaurs.”
In reviewing their original research and addressing the challenges posed by the other team, the Bristol scientists meticulously analyzed all data, including the original specimen and X-ray scans that reveal details hidden in the rock. “We had excellent images from those CT scans and further access to the fossil, which allowed us to verify all of their claims,” stated Dr. Chambi-Trowell. “We discovered that most of their concerns were unfounded.”
Professor Benton further noted: “Every aspect of the skull, jaws, teeth, and limb bones confirms that Cryptovaranoides is indeed a lizard, not an archosauromorph.”
“In our latest paper, we delve deeply into each criticism and provide more photographs of the specimen alongside 3D images from the scans, enabling everyone to examine the details closely.”
Dr. Whiteside concluded: “We had to confirm these results through a phylogenetic analysis.”
“This involves coding hundreds of anatomical features in Cryptovaranoides and other modern and fossil lizards, as well as various archosauromorphs.”
“We conducted the analysis repeatedly, and it consistently affirmed our original finding that the small reptile from Bristol is indeed the world’s oldest modern-style lizard.”
