Scientists Reconstruct a Dinosaur’s Pea-Sized Brain

A boy looks on at the skull of a dinosaur fossil in Taipei, Taiwan. Photo: Chiang Ying-ying / AP
A boy looks on at the skull of a dinosaur fossil in Taipei, Taiwan. Photo: Chiang Ying-ying / AP
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Scientists Reconstruct a Dinosaur’s Pea-Sized Brain

A boy looks on at the skull of a dinosaur fossil in Taipei, Taiwan. Photo: Chiang Ying-ying / AP
A boy looks on at the skull of a dinosaur fossil in Taipei, Taiwan. Photo: Chiang Ying-ying / AP

The study of the brain of extinct organisms and speies sheds light on their behaviors. However, soft tissues, like the brain, are not usually preserved for long periods. Hence, researchers reconstruct the brains of dinosaurs by analyzing the cranial cavities under computed tomography. It demands well-preserved braincases (the upper back part of the skull), only discovered in 2015. In that year, a Brazilian paleontologist from the Universidade Federal de Santa Maria, Dr. Rodrigo Temp Müller unearthed an exceptionally well-preserved skeleton from a fossiliferous locality in southern Brazil.

The skeleton, approximately 233 million years old (Triassic period), belongs to a small carnivorous dinosaur named Buriolestes schultzi. Its well preserved entire braincase helped researchers reconstruct the first complete brain of one of the oldest dinosaurs worldwide- whose size was similar to a hunting dog. The study was published in in the latest issue of the Journal Nature of Anatomy.

According to a report published on the university's website, the brain of Buriolestes schultzi is relatively small and weighs approximately 1.5 grams, which is slightly lighter than a pea. The shape resembles the general morphology of a crocodile brain. In addition, the researchers found well-developed structures in the cerebellum that indicate the capability to track moving prey. Conversely, the olfactory sense was not high; therefore, it is more likely that dinosaur hunted and tracked prey based on optical capability rather than its olfactory sense.

Despite the carnivorous feeding behavior of this dinosaur, it belongs to the lineage of giant, long-necked, herbivorous sauropods, the largest land animals that ever lived. However, Buriolestes schultzi is considered the earliest member of this lineage. So, the new brain reconstruction allows researchers to analyze the brain evolution of this impressive lineage.



Study Sheds Light on Origin of Australia's Odd Echidna

A team of scientists believe many of the echidna's unusual traits were first developed millions of years ago when its ancestors splashed through the water. ROMEO GACAD / AFP
A team of scientists believe many of the echidna's unusual traits were first developed millions of years ago when its ancestors splashed through the water. ROMEO GACAD / AFP
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Study Sheds Light on Origin of Australia's Odd Echidna

A team of scientists believe many of the echidna's unusual traits were first developed millions of years ago when its ancestors splashed through the water. ROMEO GACAD / AFP
A team of scientists believe many of the echidna's unusual traits were first developed millions of years ago when its ancestors splashed through the water. ROMEO GACAD / AFP

Australia's burrowing echidna evolved from a water-dwelling ancestor in an "extremely rare" biological event, scientists said Tuesday in a new study of the peculiar egg-laying mammals.

With powerful digging claws, protective spikes and highly sensitive beaks, echidnas are well suited to a life shuffling through the forest undergrowth, AFP said.

But a team of Australian and international scientists believe many of the echidna's unusual traits were first developed millions of years ago when its ancestors splashed through the water.

"We're talking about a semiaquatic mammal that gave up the water for a terrestrial existence," said paleontologist Suzanne Hand, from the University of New South Wales.

"While that would be an extremely rare event, we think that's what happened with echidnas."

Echidnas and another Australian oddity, the semi-aquatic platypus, are believed to have evolved from a common ancestor called Kryoryctes cadburyi that lived in Australia more than 100 million years ago.

Researchers studied the single known bone fragment left by this ancestor, which was discovered among a trove of fossils at Dinosaur Cove in southern Australia some 30 years ago.

Platypus bones were similar to this ancient ancestor, Hand said, with a thick and heavy structure that provided ballast for diving.

Echidnas, in comparison, had very thin bone walls that made it easier to walk on land, Hand said.

This indicated echidnas were descended from a water-dwelling ancestor but had evolved to live on land, the research found.

It was far more common for prehistoric mammals to go from land to water, Hand said, pointing towards seals, whales, dolphins and dugongs.

The researchers said these findings appeared to be supported by other echidna traits.

Echidnas have backward-facing hind feet that help them shift mounds of soil when burrowing.

These feet may have first developed as rudders helping the echidna's ancestor navigate fast-moving waterways, Hand said.

Echidnas also have a "diving reflex" when submerged in water, which tells their body to conserve oxygen helping them hold their breath for longer.

Echidnas and platypus are monotremes, a rare group of mammals that lay eggs instead of live young.

"We're hoping we'll discover other ancestral monotremes that will help unravel the early history of this most fascinating group of mammals," said study co-author Michael Archer.

The research was published in peer-reviewed journal PNAS.