A recently published study reveals the existence of a raccoon-sized Late Cretaceous armored lizard. The research, focusing on the paleontological heritage preserved in Grand Staircase-Escalante National Monument, was published in the open-access journal Royal Society Open Science. The researchers named the lizard Bolg amondol, paying homage to the goblin prince Bolg from J.R.R. Tolkien's The Hobbit.
Dr. Hank Woolley from the Dinosaur Institute, the lead author, chose the name to reflect the goblin-like appearance of these lizards, especially their skulls. "Bolg is a great sounding name. It's a goblin prince from The Hobbit, and I think of these lizards as goblin-like, especially looking at their skulls," he said. In the fictional Elvish language Sindarin, created by Tolkien, "Amon" means "mound" and "dol" means "head," referencing the mound-like osteoderms found on Bolg amondol's skull.
Woolley stumbled upon the Bolg amondol specimen while examining a jar of bones labeled 'lizard' at the Natural History Museum of Utah. "I opened this jar of bones labeled 'lizard' at the Natural History Museum of Utah, and was like, oh wow, there's a fragmentary skeleton here," said Woolley, according to a press release published on EurekAlert.
"What's really interesting about this holotype specimen of Bolg is that it's fragmentary, yes, but we have a broad sample of the skeleton preserved," noted Woolley. The skeleton included pieces of the skull, vertebrae, girdles, limbs, and bony armor called osteoderms.
Bolg amondol represents an evolutionary lineage within a group of large-bodied lizards known as monstersaurs. These creatures are characterized by their large size, pitted polygonal armor attached to their skulls, and sharp spire-like teeth. The most familiar example of monstersaurs is the Gila monsters, which still roam the deserts where Bolg amondol was recovered.
Woolley recognized the importance of the skeleton he found. "We know very little about large-bodied lizards from the Kaiparowits Formation in Grand Staircase-Escalante National Monument in Utah, so I knew this was significant right away," he stated. The Kaiparowits Formation has emerged as a paleontological hotspot over the past 25 years, producing one of the most extensive dinosaur-dominated records in North America.
Bolg amondol's closest known relative hails from the Gobi Desert of Asia, illuminating the sometimes murky path that life traveled between ancient continents. This discovery suggests that smaller animals also traveled between the once-connected continents during the Late Cretaceous Period. "This indicates there were common patterns of biogeography across terrestrial vertebrates during that time," according to the researchers.
Co-author Dr. Joe Sertich from the Smithsonian Tropical Research Institute and Colorado State University remarked on the rarity of such finds. "Even though these lizards were large, their skeletons are quite rare, with most of their fossil record based on single bones and teeth," stated Sertich. The Bolg amondol specimen, with no overlapping bones, allowed researchers to confidently assess and compare its characteristics to similar-looking lizards.
Woolley estimated that Bolg amondol was about three feet from tip to tail, possibly even larger depending on the length of the tail and torso. He compared its size to that of a Savannah monitor lizard, stating, "Something that you wouldn't want to mess around with." These large lizards likely filled roles as smaller predators hunting eggs and small animals in the Late Cretaceous subtropical floodplains of what is now southern Utah.
The discovery of Bolg amondol suggests that more large-bodied lizards existed during the Late Cretaceous Period than previously thought. "The exceptional record of big lizards from Grand Staircase-Escalante National Monument may prove to be a normal part of dinosaur-dominated ecosystems from North America," said Sertich.
Co-author Dr. Randy Irmis from the University of Utah emphasized the importance of museum collections. "Bolg is a great example of the importance of natural history museum collections," he stated. "Although we knew the specimen was significant when it was discovered back in 2005, it took a specialist in lizard evolution like Hank to truly recognize its scientific importance and take on the task of researching and scientifically describing this new species."
Written with the help of a news-analysis system.