Poposaurus Facts
Note: Although historically classified as a dinosaur, Poposaurus is no longer considered one based on current scientific understanding. It remains a fascinating prehistoric creature.
Pronunciation: POP-oh-SORE-us
Name meaning: Grandfather Lizard
| Diet | Carnivore |
| Height | 2m |
| Length | 5m |
| Weight | 400 kg |
| Environment | Land |
| Era | Triassic |
| Period | Triassic |
| Type | Other |
| Location | United States |
Although once classified as a dinosaur, Poposaurus is now known to be a pseudosuchian archosaur, making it more closely related to crocodiles than to dinosaurs. This fascinating creature lived during the Late Triassic period, between 237 and 205.7 million years ago, across what is now the southwestern and eastern United States. Despite not being a true dinosaur, Poposaurus was remarkably dinosaur-like in appearance and behaviour, representing a striking example of convergent evolution.
Measuring approximately 5 metres in length and standing about 2 metres tall at the hip, Poposaurus was a substantial predator of its time. Unlike most of its crocodile relatives, which were typically quadrupedal, Poposaurus was fully bipedal, walking and running on its powerful hind legs much like theropod dinosaurs. This upright stance gave it considerable advantages when hunting prey across the varied Triassic landscapes of ancient North America.
As a carnivore, Poposaurus would have been an apex predator in its ecosystem, using its strong jaws and sharp teeth to hunt other reptiles and early archosaurs. Its long, muscular tail provided balance whilst running, and its relatively long legs suggest it was likely a swift and agile hunter. The creature's skull remains largely unknown, but other skeletal elements have been well-preserved, giving palaeontologists excellent insight into its anatomy and lifestyle.
Poposaurus belongs to the group Poposauroidea, an unusual collection of Triassic pseudosuchians that evolved diverse body forms, including sail-backed, beaked, and even aquatic species. This diversity highlights how successful and adaptable these ancient archosaurs were during the Triassic period, long before dinosaurs became the dominant land animals.
What made Poposaurus distinctive?
Poposaurus was distinguished by its fully bipedal stance, unusual for pseudosuchian archosaurs, with long, powerful hind legs and a long tail for balance. Its large size and upright posture made it remarkably similar to theropod dinosaurs despite being more closely related to crocodiles.
Behaviour
Poposaurus was likely an active pursuit predator, using its bipedal stance and long legs to chase down prey across the Triassic landscape. Its upright posture would have given it excellent visibility whilst hunting and allowed it to cover ground efficiently in search of food.
Poposaurus FAQ
What did Poposaurus eat?
Poposaurus was a carnivore that hunted other reptiles and early archosaurs during the Late
Triassic period. As one of the apex predators of its time, it would have used its powerful jaws and sharp teeth to catch and consume a variety of prey animals across the ancient American landscape.
How big was Poposaurus?
Poposaurus measured approximately 5 metres in total length and stood about 2 metres tall at the hip. It weighed an estimated 400 kilograms, making it a substantial predator comparable in size to some of the larger theropod dinosaurs, though it was actually more closely related to crocodiles.
When did Poposaurus live?
Poposaurus lived during the Late
Triassic period, approximately 237 to 205.7 million years ago. This was long before the famous dinosaurs of the Jurassic and Cretaceous periods, during a time when archosaurs were diversifying into many different forms.
Where was Poposaurus found?
Poposaurus fossils have been discovered across the United States, specifically in Wyoming, Utah, Arizona, Texas, and Virginia. The first specimens were found in Wyoming when the creature was originally described by Maurice Goldsmith Mehl in 1915.
How do you pronounce Poposaurus?
Poposaurus is pronounced 'POP-oh-SORE-us', with emphasis on the first syllable. The name breaks down into 'Popo' meaning grandfather and 'saurus' meaning lizard, giving us 'Grandfather Lizard'.
What does Poposaurus mean?
Poposaurus means 'Grandfather Lizard' in Latin. The name combines 'popo' meaning grandfather with 'saurus' meaning lizard. This name was chosen by Maurice Goldsmith Mehl when he first described the creature in 1915.
How fast could Poposaurus run?
The exact speed of Poposaurus is unknown, but its long, powerful hind legs and fully bipedal stance suggest it was likely a swift runner. Its body plan was well-adapted for pursuit hunting, indicating it could probably run quite fast when chasing prey across the
Triassic landscape.
What type of dinosaur was Poposaurus?
Poposaurus was not actually a dinosaur at all, despite being originally classified as one. It was a pseudosuchian archosaur, making it more closely related to modern crocodiles than to dinosaurs. This is a perfect example of convergent evolution, where unrelated animals develop similar body plans.
Was Poposaurus related to birds?
Poposaurus was not closely related to birds. While it may have looked dinosaur-like, it was actually a pseudosuchian archosaur on the crocodilian branch of the archosaur family tree. Birds evolved from theropod dinosaurs, which are on a different branch entirely from Poposaurus's lineage.
How many Poposaurus fossils have been found?
Multiple Poposaurus specimens have been discovered across five US states since 1915, representing most parts of the skeleton except for the skull. Two species are currently recognised: P. gracilis (the original species) and P. langstoni, which was initially classified as a separate genus called Lythrosuchus before being reassigned to Poposaurus.
