An Australian dinosaur that was thought to be the biggest meat eater of its time has been reclassified as a timid vegetarian.
The case of mistaken identity was uncovered by an international team of palaeontologists* who re-examined a plaster cast of a footprint left by the dinosaur in Queensland about 220 million years ago.
Study leader Dr Anthony Romilio, from the University of Queensland, said that when the fossilised track was found more than 50 years ago it was thought to have been left by a large raptor-like predator* from the late Triassic period.
“For years it’s been believed that these tracks were made by a massive predator that was part of the dinosaur family Eubrontes, with legs over 2m tall,” Dr Romilio said.
“This idea caused a sensation decades ago because no other meat-eating dinosaur in the world approached that size during the Triassic period.
“But our research shows the tracks were instead made by a dinosaur from the Evazoum family – vegetarian dinosaurs that were smaller, with legs about 1.4m tall and a body length of 6m.”
The new analysis*, published in the journal Historical Biology, estimated the dinosaur was about the height of an average adult.
The research team suspected something was not quite right with the original size estimates and there was a good reason for their doubts.
“Unfortunately, earlier researchers could not directly access the footprint specimen for their study, instead relying on old drawings and photographs that lacked detail,” Dr Romilio said.
The fossilised footprint was discovered about 200m underground in a coal mine near Ipswich, about 40km west of Brisbane, in the 1960s.
The mine has long since closed, but fortunately in 1964 geologists* and the Queensland Museum mapped the tracks and made plaster casts, which are now used in research.
German fossil expert and study co-author Hendrik Klein said a virtual 3D model was made of the dinosaur footprint and then emailed to team members across the world to reanalyse.
“The more we looked at the footprint and toe impression shapes and proportions, the less they resembled tracks made by predatory dinosaurs,” Mr Klein said.
“This monster dinosaur was definitely a much friendlier plant eater.
“This is still a significant discovery even if it isn’t a scary Triassic carnivore*. This is the earliest evidence we have for this type of dinosaur in Australia.”
- palaeontologists: scientists who study fossils
- predator: animal that kills and eats other animals
- analysis: careful and detailed study of something
- geologists: scientists who study the physical nature and history of Earth
- carnivore: meat eater
- How long ago was this footprint thought to have been left by the dinosaur?
- Where was the footprint found?
- How big was the dinosaur estimated to be, according to the new analysis?
- Why did the research team suspect the original size estimates were not right?
- What sort of model did they make of the footprint?
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1. Exhibit labels
Create two exhibit labels that could accompany the cast of the dinosaur footprint at the museum where it is displayed. Create one of the labels to show what might have been written on it before this most recent study and another that gives the most up-to-date findings about the footprint.
Time: allow 30 minutes to complete this activity
Curriculum Links: English; Science
Research to find out more about the Triassic period. Record three interesting facts.
Time: allow 20 minutes to complete this activity
Curriculum Links: English; Science
Stretch your sentence
Find a “who” in the story – a person or an animal. Write it down.
Add three adjectives to describe them better.
Now add a verb to your list. What are they doing?
Add an adverb about how they are doing the action.
Using all the words listed, create one descriptive sentence.