By Stephen Beech via SWNS
An “agile and lightweight” predecessor to the dinosaurs – dating back 237 million years – has been discovered in Brazil.
Scientists say Gondwanax paraisensis is a new species of “silesaurid” – an extinct group of reptiles that lived millions of years before dinosaurs roamed Earth.
There is debate among researchers whether silesaurids were true dinosaurs or not.
The conflict arises because silesaurids exhibit characteristics typical of dinosaurs, but also possess features that still appear quite primitive.
Paleontologists say Gondwanax paraisensis reached about one meter (3.2 ft) in length and weighed between three and six kilos (6.6lbs and 13.2lbs), based on the recovered fossils.
They believe it walked on four legs and moved on land, but said it was difficult to say what it ate since no remains of its teeth or skull have yet been discovered.
Dr. Rodrigo Temp Müller, of the Federal University of Santa Maria (UFSM), Brazil, said: “Discoveries over the past decade have allowed us to completely reconstruct the skeletons of the earliest dinosaurs.
“Now, we face an even greater challenge: understanding the anatomy of the forms that existed before these dinosaurs.
“Fortunately, new finds, such as Gondwanax paraisensis, have been helping us to address this question.”
He said the newly discovered species had a pelvis and legs with many specialized bony structures, indicating an “advanced locomotor capability” compared to other reptiles that lived alongside it.
Dr. Muller said: “The gracile structure of its vertebrae suggests it was an agile and lightweight animal.”
The remains, described in the journal Gondwana Research, were excavated in the municipality of Paraíso do Sul by fossil hunter Pedro Aurélio.
Mammalian precursors called cynodonts, dicynodonts, and Parvosuchus aurelioi, a small crocodile, have been previously found there.
The remains were donated to the Palaeontology Research Centre at UFSM, where Dr. Müller performed the preparation and study of the specimen.
He said: “The remains were covered by a thick layer of rock.
“At first glance, only some portions of the vertebrae were visible.”
He took the materials to the lab and began a meticulous preparation process using acid and pneumatic hammers.
After several days of work, part of the skeleton of an unknown reptile was finally revealed.
Dr. Muller said: “This discovery is attributed to Pedro Aurélio’s deep enthusiasm for prospecting and his love for fossils.
“He was the one who noticed something unusual in the soil and took the care to collect this material, donating it to our research center.
“While organizing the materials donated by Mr. Aurélio, a femur caught my attention.
“As I sifted through the associated items, I noticed several elements typical of silasaurids. It was incredible.
“The details of the fossilized skeleton suggest that the material belongs to an animal from the dinosaur lineage, possibly an actual dinosaur or a very close relative.
“At approximately 237 million years old, this is one of the oldest fossils from this lineage ever
discovered.
“Based on the dimensions of the preserved elements, it is estimated that Gondwanax paraisensis would have reached about one meter in length.
“Since no teeth or other cranial elements were recovered, it was not possible to infer its dietary habits.
“Nevertheless, most related animals were herbivorous or omnivorous, making it likely that it also had a similar diet.”
He explained that “Gondwanax” means “lord of Gondwana” – referring to the future dominance that dinosaurs would have in the landmass known as Gondwana, the southern region of the supercontinent Pangaea, while “paraisensis” honors the municipality of Paraíso do Sul.
Dr. Muller said: “The femur lacks one of the key crests for muscle attachment that is common in dinosaurs.
“In contrast, its sacrum – the region connecting the pelvis to the spine – appears quite advanced, as it has
more vertebrae than other close related silesaurids.
“This unusual combination of features may indicate that Gondwanax paraisensis moved differently from other dinosaur precursors.
“The rise of dinosaurs remains a challenging topic to investigate, especially due to the scarcity of fossils from their precursors.
“Brazil is internationally known for housing some of the most complete and well-preserved fossils of the oldest
dinosaurs in the world, approximately 230 million years old.
“On the other hand, while essential for understanding the origins of this group, fossils of dinosaur precursors are still very rare.
“Understanding the characteristics of these precursors could shed light on what was crucial for the dinosaurs’ evolutionary success.
“In recent years, discoveries of this type have been reported from fossil layers about 237 million years old in Brazil.
“However, these fossils are usually fragmentary and not very informative.”
He added: “This finding demonstrates that, in addition to preserving some of the world’s dinosaurs, Brazil also harbors fossils of the reptiles that marked the beginning of the evolutionary history of dinosaurs, revealing previously unknown details of this journey that transformed terrestrial ecosystems during the Mesozoic Era.”
