A prehistoric lizard the size of a raccoon has just been identified in southern Utah. This specimen, named Bolg amondol, sheds new light on the diversity of giant lizards during the age of dinosaurs.
Researchers discovered this new member of the monstersaur family in the collections of the Natural History Museum of Utah. Although the skeletal fragments are partial, they allowed for the reconstruction of part of its anatomy and lifestyle. This lizard, whose name was inspired by a Tolkien character, shared its habitat with other large lizard species.
Artist's reconstruction of Bolg amondol, depicted raiding an oviraptorosaur dinosaur nest in the lush habitat of the Kaiparowits Formation.
Credit: Cullen Townsend
The study, published in
The Royal Society, highlights the unique ecosystem of Utah 76 million years ago. Bolg amondol coexisted with several other lizard species, indicating a stable and resource-rich environment. This discovery also underscores the importance of museum collections for paleontology.
The name Bolg amondol, inspired by Tolkien's Elvish language, reflects the goblin-like appearance of this lizard. Researchers used skull fragments, limb bones, and osteoderms to identify this new species. These elements, though fragmentary, provided valuable insights into the anatomy and evolution of monstersaurs.
This discovery opens new perspectives on the biodiversity of giant lizards in the Late Cretaceous. It also shows that similar species existed on both sides of the ancient continent of Laramidia, suggesting common migration patterns among terrestrial vertebrates.
Size comparison between the holotype specimen of Bolg amondol and a modern Gila monster (Heloderma suspectum, right). Gold: preserved skeletal elements. Light gray: reconstructed elements. Dark gray: missing parts, based on publicly available CT scans.
Credit: Natural History Museum of Utah/Bureau of Land Management What is a monstersaur?
Monstersaurs are a family of lizards characterized by their large size and sharp teeth. They also possess osteoderms, bony plates embedded in their skin, which form protective armor.
These lizards, whose modern representatives include the Gila monster, have an evolutionary history dating back over 100 million years. However, their fossil record is fragmentary, making each new discovery crucial.
Bolg amondol, measuring three feet (about 1 meter) in length, exemplifies the diversity of monstersaurs. Its discovery helps fill gaps in our understanding of their geographic distribution and evolution.
Monstersaurs likely played a key role in their ecosystems as predators of small prey. Studying them offers insights into past ecological dynamics.
How do fossils inform us about ancient ecosystems?
Fossils, like those of Bolg amondol, are windows into vanished ecosystems. They reveal not only the existence of species but also their interactions and environment.
The presence of multiple large lizard species in the Kaiparowits Formation suggests a rich and diverse ecosystem. This indicates an abundance of resources and ecological niches.
Fossils also allow us to trace migrations and connections between continents. Bolg amondol shares traits with Asian species, revealing common dispersal patterns.
Finally, fossil studies highlight the importance of preserving paleontological sites. These discoveries often depend on the protection of public lands and museum collections.