A new theropod dinosaur has been discovered from the little-explored region of northern Paraná in modern Brazil. Named Vespersaurus, it had a lightweight skeleton, similar to modern birds, and sharp teeth and claws like most of its flesh-eating cousins. The new partial skeleton represents one of the most well-preserved dinosaurs now known from Brazil, adding to an impressive existing national dinosaur record.
However, distinct from most of its theropod relatives, such as Velociraptor, this little dinosaur danced around just on one of its toes! This is a condition known as being ‘monodactyl’, and the first time it has been discovered in a dinosaur from Brazil. Modern examples of this include kangaroos, and even horses with their hooved feet. Researchers were able to see this based on fossilised one-toed footprints known from the 1970s, now thought to belong to these species.
“Although difficult to substantiate, it is tempting to speculate whether some of those theropod footprints were produced by an animal similar to the new taxon. Indeed, Leonardi suggested that one such track, found in the same stratigraphic unit at a site about 50 km northwest of Cruzeiro do Oeste, was produced by a functionally monodactyl bipedal “coelurosaur””, say the authors, in their recently published study. These were discovered near the same locality as the new bones. It is thought that the middle toe would have taken all the weight while moving, with another toe on each side held off the ground.
But why did some dinosaurs become monodactyl? If we look at modern animals who have this condition, they are extremely efficient runners and jumpers. Clearly an advantage for any desert-dwelling predator. Equipped with wicked claws on its feet, this Great Dane-sized little beast would have been able to leap onto its prey before trying to rip them apart. This includes many of the now fossilised lizards, mammals, turtles, and pterosaurs that have previously been discovered nearby.
Name: Vespersaurus paranaensis
Group: Noasaurine, theropod
Age: 90 million years old, Late Cretaceous period
Location: Paraná state, southern Brazil
Geological group: Caiuá Group, Bauru Basin
Rocks found in: Dark red quartz-sandstone
Environment: Inner desert, arid climate – known now as the “Southern Hot Arid Belt”
Diet: Meat, carnivorous, small prey
Size: 5 feet in length, 80cm in height
Weight: Around 33 pounds
The name, Vespersaurus, derives from the word ‘vesper’ in Latin, which means evening or west. This is in reference to the name of the town it was discovered near, Cruzeiro de Oeste, or the ‘Western Cross’. ‘Sauros’ is Greek for lizard or saurian, and a common ending for dinosaur names.
This latest discovery helps to reveal to us just how weird and diverse many different dinosaur species were. No longer seen as lumbering giants, we now know they came in all shapes and sizes. Many had the ability to dig burrows for safety, glide and fly, climb trees, swim and fish, sprint at amazing speeds, and even brood over eggs like modern birds.
Relatives of Vespersaurus have been found across the southern continents, known geologically as Gondwana, in places like Argentina, India (it used to be much further south during the Cretaceous), and Madagascar. It is likely that as we continue to explore across Africa and South America, new discoveries will continue to challenge and shape our understanding of these beautiful animals.
Langer, Max Cardoso, Neurides de Oliveira Martins, Paulo César Manzig, Gabriel de Souza Ferreira, Júlio César de Almeida Marsola, Edison Fortes, Rosana Lima et al. “A new desert-dwelling dinosaur (Theropoda, Noasaurinae) from the Cretaceous of south Brazil.” Scientific Reports 9, no. 1 (2019): 9379. https://doi.org/10.1038/s41598-019-45306-9