"I've got a dinosaur!" When palaeontologistA scientist who studies fossils to learn about history. Chris Griffin dug up an enormous thigh bone in Zimbabwe, he knew he "was holding Africa's oldest dinosaur".

Mbiresaurus raathi¹ was a dog-sized plant-eater living in the late TriassicA geologic period spanning from 252 to 201 million years ago.  on a supercontinent called PangeaAlso known as Pangaea, the supercontinent that existed before the Earth's land separated out into different continents. . The descendants of this small dinosaur were the largest creatures² ever to walk on Earth.

Around 252 million years ago, a devastating event³ wiped out 90% of all life. It was an opportunity for the "terrible lizards." They conquered land, sea and air until 187 million years later, when a massive asteroid⁴ ended the age of the dinosaurs.

Mbiresaurus raathi "shows that dinosaurs didn't start out worldwide, ruling the world from the very beginning," says Griffin. Early dinosaurs lived in hot and humid southern regions. They went north when the climate changed.

This is "one of the most important dinosaur discoveries anywhere in the world," says palaeontologist Stephen Brusatte. But what do the lives of ancient monsters have to do with us?

Very little, some argue. Around 60,000 years ago, humans developed fine stone tools and deadly weapons. This began a technological revolution that took humans from caves to cities and into space.

"The dinosaurs became extinct because they didn't have a space program," wrote science fiction writer Larry Niven. Technology, not history, will solve today's problems.

Not true, argues palaeontologist Mary Schweitzer. "The fossil record," she says, "tells us that climate change is the planet's 'normal' state." Discovering five previous mass extinctions helps us understand whether humans are "causing a sixth global die-off".

"The best way to look ahead is to look behind," says Schweitzer. For millions of years, dinosaurs were incredibly successful.

They are also not extinct. Some survived the asteroid. We share our planet with at least 10,000 species of dinosaur: the birds.

In the mid-1990s, a Chinese farmer found the world's first feathered dinosaur. Since then, research has confirmed that birds are dinosaurs.

"Learning the secret of flight from a bird," wrote Orville Wright, "was a good deal like learning the secret of magic from a magician." He and his brother Wilbur invented the aeroplane in 1903. So perhaps we have dinosaurs to thank for air flight and space travel?

Yes: Over 99% of all species are extinct. If we want to understand all the ways to survive on Earth, we must look back into our distant past.

No: Fossil hunting is fun and dinosaur films are entertaining. But it is a waste of money to dig up the past when we should be worrying about the future of humanity.

Or... Science is about exploring the unknown. When we look deep into the past, we don't know what we will find. But if we do not look, we will never know.

Palaeontologist - A scientist who studies fossils to learn about history.

Triassic - A geologic period spanning from 252 to 201 million years ago.

Pangea - Also known as Pangaea, the supercontinent that existed before the Earth's land separated out into different continents.