SANTA MARIA, Brazil — The first complete brain of a dinosaur has been unveiled by scientists. Weighing less than a pea, it belonged to a meat eater that walked the Earth 233 million years ago. Named Buriolestes schultzi, it is an ancestor of the long necked sauropods — the most colossal of them all.
Amazingly, the perfectly preserved skeleton of the ferocious dinosaur included the braincase, enabling a precise reconstruction of its gray matter. Stunning computer images reveal regions involved in coordination: sight, smell, intelligence, and even reproduction.
The remarkable discovery sheds fresh light on the evolution of the biggest land animals that ever lived.
“The brain is a window into its behavior — and intelligence,” paleontologist Dr. Rodrigo Muller, of the Federal University of Santa Maria, tells South West News Service.
The findings show Buriolestes was an athletic and skilful hunter. It had better eyesight than smell. And it was not as smart as the Tyrannosaurus Rex or even today’s birds. The pet sized creature weighed about 14 pounds. It was small but vicious, similar in stature to a fox. Its sharp, curved teeth and claws would have ripped lizards and primitive mammals to shreds, as well as the young of other dinosaurs. It also ate insects.
Buriolestes was hunted itself by the “killing machine” known as Gnathovorax. The ten foot tall dinosaur was the apex predator of the period.
“The brain of Buriolestes is relatively small, weighing about 1.5 grams (0.05oz) – which is slightly lighter than a pea,” says Muller. “The shape is primitive, resembling a crocodile’s. In addition, the presence of well developed structures in the cerebellum indicates the capability to track moving prey. Conversely, the olfactory sense was not good. Buriolestes hunted and tracked prey based on sharp eyesight rather than smell.”
How did Muller analyze the ancient dinosaur’s brain?
Soft organs, such as the brain, don’t survive fossilisation. So his team used CT (computed tomography) scans to peer into the internal cranial cavities. “We access isolated sections of the skull, filling the gaps of each. When we put these regions together we get a 3D representation of the space — or endocast,” says Muller.
The X-rays mapped the cerebellum that controls coordination, balance and posture as well as the optical lobe, the visual processing center. They also revealed the olfactory bulb and tract responsible for smell and the cerebrum that triggers intelligence and conscious thoughts.
The pituitary gland at the base of the brain was drawn up too. It produces hormones that fuel growth, blood pressure, and reproduction.
“The technique demands well-preserved braincases, which envelopes the tissues. It is the upper and back part of the skull, which forms a protective case around the brain,” explains Muller.”Buriolestes dates back to the dawn of the dinosaurs. So far, complete braincases from the oldest dinosaurs worldwide were unknown. It has helped unlock the secrets of its way of life.”
What do scientists know about Buriolestes?
The bizarre animal measured about four feet from head to tail. It had a long neck, razor sharp teeth and three long claws on each of its four limbs. It ran on two legs.
Its remains were unearthed in 2015 during an expedition to the rainforest of southern Brazil led by Dr. Muller.
“It is a well known dinosaur graveyard,” says Muller. “The place is a ravine with other fossilized skeletons in a farm.”
Buriolestes lived during the Triassic period, when South America was still part of the super-continent called Pangaea. Despite being a carnivore, it is the earliest member of the plant-eating sauropods – that weighed up to 100 tons and reached 110 feet long.
“The reconstruction allows us to analyze the brain evolution of the biggest land animals that ever lived,” notes Muller.
One of the most conspicuous trends is the increase of the olfactory bulbs. These were relatively small in Buriolestes, but became very large in sauropods. “The development of a high sense of smell could be related to the acquisition of a more complex social behavior – seen in several vertebrate groups,” Muller contends. “Alternatively, it has also been observed high olfactory capabilities played an important role in foraging – helping animals to better discriminate between digestible and indigestible plants. Finally, another putative explanation for the better smell in sauropods relies on the capability to pick up the scent of predators.”
The pituitary gland is also related to size and is proportionally small in Buriolestes, On the other hand, it is very large in the giant sauropods. “Hence, we can associate the development of the gland with the gigantism of sauropods,” says muller.
Not the sharpest breed of dinosaur
The study published in the Journal of Anatomy also calculates the intelligence of Buriolestes based on brain volume and body weight.
“The values obtained are higher than that of the giant sauropods — like Diplodocus and Brachiosaurus — suggesting a decrease in brain size compared to body,” says Muller. “It changed across the time, not only in general morphology, but also in the neurological functions. The brain anatomy changes together with the body plan of these animals. It is interesting because several other lineages present an increase in this phenomenon – known as encephalization – through time. “Nevertheless, the ‘cognitive capability’ of Buriolestes is lower than that of theropod dinosaurs, the lineage that includes T Rex and Velociraptor of Jurassic Park fame – and birds.”
In the view of most experts, birds are ‘living dinosaurs’. Their key skeletal features – as well as nesting and brooding behaviours – actually arose first in some dinosaurs.
Story written by SWNS reporter Mark Waghorn