A small venomous reptile from the Late Triassic (Norian) of the southwestern United States
Reptile feeding strategies encompass a wide variety of diets and accompanying diversity in methods for subduing prey. One such strategy, the use of venom for prey capture, is found in living reptile clades like helodermatid (beaded) lizards and some groups of snakes, and venom secreting glands are also present in some monitor lizards and iguanians.
In the Press
Venomous reptile species from the Late Triassic unearthed in Arizona
Phys.org
Venomous Lizard From Late Triassic Discovered In Arizona
Reptiles Magazine
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Fossils of previously unknown triassic era reptile found in Arizona
San Diego Union Tribune
New venomous reptile species from the Late Triassic unearthed in Arizona
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“We know very little about the origins of reptile venom systems outside of living snakes and lizards, so Microzemiotes sonselaensis is a very exciting addition to a small handful of Mesozoic envenomaters.”
Helen Burch
PhD Student, Virginia Tech Geosciences
For All Readers - AI Explainer
What is the new discovery, and why is it significant?
Researchers have discovered a potentially venomous reptile species from the Late Triassic period in northeastern Arizona, named Microzemiotes sonselaensis. This is significant because it adds to our understanding of how reptiles used venom as a strategy for hunting and defense millions of years ago. It’s also the oldest known example of preserved venom-conducting teeth in a reptile jaw, expanding our knowledge of venom use across different prehistoric species.
What makes Microzemiotes sonselaensis venomous?
The researchers identified grooves running along the teeth of Microzemiotes sonselaensis, which are similar to those found in living beaded lizards, known to use these grooves to deliver venom. These grooves suggest that this reptile likely used venom to subdue prey, much like modern venomous reptiles.
How does this species compare to other venomous reptiles of its time?
Microzemiotes sonselaensis is much smaller than other venomous reptiles from the Late Triassic, such as Uatchitodon. The discovery indicates that venomous strategies were present in reptiles of various sizes, suggesting that venom use was a more widespread adaptation than previously thought.
What part of the fossil was discovered, and how does it help in identifying the species?
Researchers found a partial left jawbone (dentary) with three distinctively grooved teeth. The unique shape and positioning of these teeth, combined with the tooth replacement patterns and grooves, helped identify the species and hypothesize its venomous nature.
How does this discovery change our understanding of venom evolution in reptiles?
This discovery pushes back the timeline of venom use in reptiles by millions of years. It shows that venomous feeding strategies may have evolved independently in different reptile groups during the Late Triassic. It also highlights that venom use was likely a more common and varied strategy than previously understood.
Why is it hard to determine the exact evolutionary lineage of Microzemiotes sonselaensis?
While the teeth and jawbone share similarities with some modern reptiles, like lizards and snakes, there isn’t enough fossil evidence to definitively place Microzemiotes sonselaensis within a specific reptile family. Its unique features suggest it could be an early representative of a group of reptiles that evolved venomous traits independently.
What does this discovery tell us about reptile diversity during the Late Triassic?
The Late Triassic was a period of great diversity among reptiles, with many different feeding strategies evolving. The discovery of Microzemiotes sonselaensis adds to the growing evidence that venom was a key survival tool, used by multiple species across a wide range of sizes and evolutionary lineages.
How might this species have used its venom in the wild?
Like modern venomous reptiles, Microzemiotes sonselaensis likely used venom to immobilize or kill prey. It may have been a predator or even used its venom defensively against larger animals, helping it survive in a competitive and dangerous environment.
What’s next for this research?
Researchers hope to find more fossil evidence to better understand the evolutionary relationships of Microzemiotes sonselaensis and other venomous reptiles of the Mesozoic era. Further studies will also explore how widespread venom use was among ancient reptiles, helping us piece together the complex puzzle of their evolution.
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