LONDON.- A new fossil is allowing scientists to get their claws into the tricky topic of Triassic evolution.
While dinosaurs tend to grab the spotlight, there were a variety of smaller animals that lived alongside them. One group of these were the lagerpetids, close relatives of pterosaurs that lived during the Triassic.
There are relatively few lagerpetids known to scientists, so the discovery of a new species, Venetoraptor gassenae, has excited palaeontologists. Even more exciting, however, is that unlike many other fossils from the group, large parts of its skull and hands still survive.
This is important, because these areas of the body are crucial to understand an animal’s lifestyle as they can shed light on its diet and behaviour. With a sharp beak and claws, Venetoraptor could have been a predator, though there’s not currently enough evidence to confirm this.
Together with other lagerpetid fossils found in Africa, Europe and the Americas, Venetoraptor suggests that these little-known animals might have been much more widespread than previously thought.
Dr Rodrigo Müller, who led research into the new species, says, ‘Venetoraptor is the kind of discovery that changes paradigms. Looking at its unexpected form, it is impossible to not think of all the hidden diversity waiting to be discovered.’
Professor Paul Barrett, a dinosaur expert from the Museum, adds, ‘Venetoraptor has well-preserved skull material, which gives us a clearer idea of what these animals might have been eating for the first time.’
‘By understanding what the head looked like, this animal provides deeper insights into the relationships of lagerpetids with other reptile groups that existed around the origins of dinosaurs and pterosaurs.’
The findings of the study were published in the journal Nature.
What are the lagerpetids?
The lagerpetids are a group of reptiles that lived during the Middle and Late Triassic, which lasted from 247 to 201 million years ago. Their fossils are most commonly found in North and South America but tend to be incomplete, which limits how much can be learned from them.
Historically, the bones which have survived suggested that they might have been some of the closest relatives of the dinosaurs. As new fossils have been discovered, however, the evidence now points to the lagerpetids being the closest relatives of pterosaurs instead.
‘When the first lagerpetids were discovered in the 1960s, there were relatively few species to examine,’ Paul says. ‘In the past decade, there have been a flurry of new papers describing new species and reinterpreting old ones, revealing how these groups are linked to the origins of flying reptiles.’
The origin of pterosaurs is something of a mystery, because by the time they arrive in the fossil record these reptiles already have the specialised features that allowed them to become the first flying vertebrates. Looking at close relatives, like the lagerpetids, allows palaeontologists to find possible routes the pterosaurs might have taken on the road to flight.
Recent research on a different, more primitive lagerpetid called Scleromochlus suggested that these animals might have been able to climb. However, as the fossils of this species are not well preserved, many questions remained about the more general lifestyle of the animals.
To answer these questions, palaeontologists needed more well-preserved fossils. Rodrigo regularly goes searching for fossils at southern Brazil’s Buriol Site, an area known for its fossils of Late Triassic dinosaurs and crocodile relatives.
Following heavy rain in 2022, his searching paid off when the first few fossils of Venetoraptor were exposed. Even more bones lay deeper inside the rock, with some still articulated in the same positions they would have been while the lagerpetid was alive.
‘Usually, most lagerpetids are constructed from the isolated bones of several fragmentary animals,’ Rodrigo says. ‘The new specimen preserves several portions of a single individual, which provides a more reliable idea of the body proportions of this bipedal creature.’
‘This new material also provides the first reliable look into the face of these enigmatic reptiles and gives greater insights into their hands, which are important to understand their evolution.’
What was Venetoraptor like?
Using the bones, the team estimate that Venetoraptor was around a metre long and about 30 centimetres tall at the hips. It would have weighed around four to eight kilograms, or about the same as a domestic cat.
Like cats, it’s possible that Venetoraptor could have been a hunter. It had a sharp beak similar to those of eagles, with a hook at the end which was well-adapted for tearing flesh or piercing hard fruits. It may have been able to find food up in the canopy, with clawed legs and feet that might have allowed the reptile to climb trees.
While the evidence seems compelling, it isn’t yet conclusive. The team plan to compare the shape of its beak and claws with those of living animals to find further evidence of how Venetoraptor might have used them.
Whatever its role in the ecosystem, it’s likely that Venetoraptor wouldn’t have been alone. Another lagerpetid, known as Ixalerpeton, has previously been found at the site raising the prospect that they lived alongside one another.
While it’s not the first time this has been found, it suggests the animals occupied a wide range of roles in the environment. The researchers reinforced this idea by carrying out what is known as a disparity analysis, which shows how diverse the body shapes of these animals might have been.
‘A disparity analysis has never been carried out on lagerpetids before, as the fossils have generally been too fragmentary,’ Paul says. ‘It shows they had a fairly wide variety of body shapes and characteristics, which challenges the previous view that all lagerpetid species were quite similar.’
While these species would have lived alongside each other all over the world, their time on Earth was fairly short. The lagerpetids became extinct by the middle of the Late Triassic, leaving the dinosaurs and pterosaurs to dominate the world’s ecosystems.
