Siamotyrannus
Siamotyrannus was a big meat-eating dinosaur that stomped through ancient Thailand. It had strong legs and sharp teeth, and it hunted other animals. Scientists are still figuring out exactly what kind of theropod it was!1
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Fun facts
Its fossil includes part of the pelvis, back vertebrae, and tail vertebrae, but no skull has been found yet.1
Siamotyrannus had two vertical ridges on its hip bone, a feature that may be unique to this dinosaur.12
Even though its name means 'Siamese tyrant', scientists now think it might not be a true tyrannosaur. Some studies place it with allosaurs or other meat-eaters.1
The first fossil was found in 1993 by a man named Somchai Traimwichanon at a site in Thailand.1
Some scientists think Siamotyrannus was closely related to another dinosaur called Siamraptor, which also lived in Thailand.1
Most asked questions about Siamotyrannus
?How big was Siamotyrannus?
Scientists are not sure, but estimates range from about 6 meters (20 feet) to 10 meters (33 feet) long, and it may have weighed between 500 kg and 1.75 tonnes.1
?Was Siamotyrannus a tyrannosaur?
Probably not. Even though its name means 'Siamese tyrant', most scientists now think it was an allosauroid or a close relative of Siamraptor, not a true tyrannosaur.1
?What did Siamotyrannus eat?
It was a meat-eater. It had sharp teeth and strong legs to hunt other animals.3
?When did Siamotyrannus live?
It lived during the Early Cretaceous period, about 145 to 120 million years ago.1
?Where was Siamotyrannus found?
Its fossils were found in Thailand, at the Phu Wiang 9 site in Khon Kaen province.1
?Did Siamotyrannus have a skull?
No skull has been found yet. The only fossils discovered are part of the pelvis, back vertebrae, and tail vertebrae.1
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Myth buster
Myth: Siamotyrannus was a true tyrannosaur, like T. rex.
Truth: Scientists now think it may not be a tyrannosaur at all. Many studies place it with allosauroids or other theropods, and its exact family is still debated.1
For dino experts
- Scientific name
- Siamotyrannus
- Named by
- Buffetaut et al. 19963
- Group
- Other meat-eaters
- Family / clade
- Metriacanthosauridae3
- Classification
- Theropoda > Allosauroidea3
- Age of the rocks
- 126 to 121 million years (Barremian)3
- Rock formations
- Sao Khua3
- Countries
- Thailand3
- Fossil records
- 1 in the Paleobiology Database3
- Discovery
- In 1993, Somchai Traimwichanon found a partial skeleton at Phu Wiang 9 in Thailand. In 1996, Eric Buffetaut, Varavudh Suteethorn, and Haiyan Tong named it Siamotyrannus isanensis.13
- Still debated
- Scientists still debate what group Siamotyrannus belongs to. It might be an allosauroid, a primitive coelurosaur, or something else entirely.1
Where the facts come from
- Siamotyrannus (en.wikipedia.org)
- PBDB Taxon (paleobiodb.org)
- Siamotyrannus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.
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