A new species of Triassic mammal-like reptile has recently discovered in Poland. The new fossils shed insight on the early ancestors of mammals, dinosaurs, and reptiles.
The Triassic period (252-201) began with a mass extinction event that wiped out over 90 percent of life on Earth but as the world recovered an unprecedented diversification of species occurred.
During the Triassic period, mammal-like reptiles called Therapsids co-existed with the ancestors of dinosaurs, crocodiles, mammals, pterosaurs, turtles, frogs, and lizards. The Dicynodonts are one group of Therapsids.
In the fossil record, the Triassic is where we see the first dinosaurs as well as ancestors of today’s reptiles and mammals. This was also a time when all the Earth’s landmasses came together to form the super-continent Pangea.
Dicynodonts were the dominant terrestrial herbivores in the Middle and Late Triassic, but they were thought to have gone extinct before dinosaurs became the most abundant four-footed terrestrial animal on Earth.
The facts about Dicynodonts:
They were all herbivores;
The sizes ranged from small burrowers to large browsers;
Most Dicynodonts were toothless;
They survived the Permian mass extinction to be the dominant terrestrial herbivores in the Middle and Late Triassic; and
They most likely died out before dinosaurs became the dominant form of tetrapod on land.
However, researchers from Uppsala University in Sweden have unearthed new fossil evidence that has called into question everything researchers previously knew about dicynodonts.
While excavating near the Polish village of Lisowice, the researchers found fossils that belonged to a new species of Dicynodont, which they called Lisowicia bojani. The species was named Lisowicia bojani after the village and a German comparative anatomist named Ludwig Heinrich Bojanus who worked in Vilnius and made several important anatomical discoveries.
“The discovery of Lisowicia changes our ideas about the latest history of Dicynodonts, mammal Triassic relatives,” said Tomasz Sulej, a member of the research team. “It also raises far more questions about what really make them and dinosaurs so large.”
A study detailing the findings was published in the journal Science.
After sorting through and analysing thousands of bones and bone fragments from the area, the researchers pieced together Lisowicia bojani.
Lisowicia bojani reached an estimated length of more than 14.7 feet (4.5 m), height of 8.5 feet (2.6 m), and body mass of 9 tons.
It had erect-gait forelimbs, suggesting upright limb posture, like that of modern large mammals such as rhinoceroses and hippopotami. Previously, Triassic Dicynodonts were characterised only with sprawling forelimbs (the gait of reptiles).
Lisowicia bojani also lived much later, ten million years later, compared to other Dicynodont species, and as such co-existed with the first sauropodomorph dinosaurs.
“Dicynodonts were amazingly successful animals in the Middle and Late Triassic. Lisowicia is the youngest Dicynodont and the largest non-dinosaurian terrestrial Therapsids from the Triassic,” said Grzegorz Niedzwiedzki, a co-author of the study.
“It’s natural to want to know how Dicynodonts became so large. Lisowicia is hugely exciting because it blows holes in many of our classic ideas of Triassic ‘mammal-like reptiles’.”
More than 1,000 prehistoric find have been made in and around Lisowice, which is thought to have been a river deposit during the Late Triassic period.