One of the oldest fossils ever discovered might finally unravel the mystery of how ordinary lizards evolved into dinosaurs.
Paleontologists identified a 237-million-year-old, four-legged, new reptile species roughly the size of a small dog in Brazil.
The newly found species, named Gondwanax paraisensis, featured several features common among the early ancestors of dinosaurs, with some that have never found before.
The team believes that the fossil characteristics could help fill in the gaps in the evolutionary history.
This ancient reptile was first discovered by a local doctor in the town of Paraiso do Sull, who later donated the fossil in 2021.
A re-analysis of the remains, conducted by researchers at the Federal University of Santa Maria, found the creature roamed the country during the Triassic period when mammals, crocodiles, turtles and frogs all first came into being.
The arrival of other animals meant the ancient reptile had to compete for survival due to them all residing on what was the supercontinent of Pangea, which had a ferocious jungle ecosystem sweltering in a climate far hotter than ours today.
The reptile has some features that have been found among dinosaur ancestors, known as silesaurids, such as a notch below the head of the thigh bone and a flat surface on the top of the femur where it connects to the hip.
The traits helped scientists determine that Gondwanax paraisensis had to be one of the oldest known silesaurids.
But the team identified a unique bone feature that connected the spine to the hips.
This area, known as a sacrum, was composed of three vertebrae
The 39-inch-long, up to 13-pound lizard’s name means ‘lord of Gondwana’ in honor of in the southernmost region of the Pangaea, known as the Gondwana landmass.
Paleontologist Rodrigo Temp Müller noted that the creature’s vertebrae showed it was likely an ‘agile and lightweight animal.’
Its unique, competitive abilities and its presence near so many other fossils from this same Triassic period will help researchers understand the ecosystem in which dinosaurs first evolved.
‘Because it’s so old, it gives us clues as to how dinosaurs came to be,’ said Müller.
‘The most important part of this finding is its age,’ he explained.
Paleontologists have long debated whether silesaurids were, themselves, true dinosaurs, simply ‘non-dinosaur dinosauriforms,’ or potentially a ancestor to these famous and gigantic creatures that once ruled the Earth.
‘Understanding the characteristics of these precursors could shed light on what was crucial for the dinosaurs’ evolutionary success,’ Müller and his team said in a statement.
And the region itself played a key role in the major evolutionary shifts that occurred.
A vast mountain range called the ‘Transgondwanan Supermountain‘ — that reached as high up as the Himalayas, but was nearly four times as long — ‘supercharged’ the evolution of life, Australian scientists found in 2022.
The appearance of the first large animals around 575 million years ago coincided with the tectonic formation of this range, according to geochemist Dr Ziyi Zhu of the Australian National University in Canberra.
‘There’s nothing like these two ranges today,’ Dr Zhu said at the time.
It was the gradual erosion of these mega-mountains by weather elements that led to vital nutrients, like iron and phosphorus, being washed into the oceans in greater volumes, Dr Zhu and her team explained.
This influx of ingredients helped to spur on life and evolution towards larger and more complex forms.
The resulting increase in oxygen-producing plant-like algae and other species, accompanied by the rapid burial of organic carbon and iron, would have led to increases in the atmospheric levels of oxygen.
‘The increase in atmospheric oxygen associated with the erosion of the Transgondwanan Supermountain is the largest in Earth’s history and was an essential prerequisite for the appearance of animals,’ Dr Zhu said.
The second half of the new reptile discovery’s name, paraisensis, was selected to pay respect to Paraiso do Sul, the town in Brazil’s southernmost state of Rio Grande do Sul, where the fossil was first unearthed.
Müller noted that the local physician who donated the fossil, Dr Pedro Lucas Porcela Aurelio, could only make out a few visible parts of the creature’s vertebrae when he first examined the thick rock around the fossil.
Dr Aurelio first noticed the fossil in 2014, unaware that the find dated to the Triassic period, between 252 million and 201 million years ago.
‘Being the first human to touch something from 237 million years ago is extraordinary,’ Dr Aurelio told Reuters.
‘It’s an indescribable feeling,’ the local doctor continued, adding that has been a paleontology buff since childhood.
This post was originally published on here
