Analysis revealed in the present day within the peer-reviewed Journal of Vertebrate Paleontology describes a newly found species of dinosaur — named the ‘one who causes worry’, or Llukalkan aliocranianus.
Round 80 million years in the past as tyrannosaurs dominated the Northern Hemisphere, this lookalike was one in every of 10 presently identified species of abelisaurids flourishing within the southern continents.
A fearsome killer, Llukalkan was “seemingly among the many high predators” all through Patagonia, now in Argentina, throughout the Late Cretaceous as a consequence of its formidable measurement (as much as 5 meters lengthy), extraordinarily highly effective chew, very sharp enamel, big claws of their ft and their eager sense of odor.
It had a wierd quick cranium with tough bones, so in life its head had bulges and prominences like some present reptiles such because the Gila monster or some iguanas. Its listening to was additionally completely different to different abelisaurids. The make-up of its cranium suggests this was higher than many of the different abelisaurids and just like that of modern-day crocodiles.
Its full identify comes from the native Mapuche for ‘one who causes worry’ — Llukalkan, and the Latin for ‘completely different cranium’ — aliocranianus.
It lived in the identical small space and time frame as one other species of furileusaurian (stiff-backed lizard) abelisaurid — Viavenator exxoni — just some million years earlier than the tip of the age of dinosaurs.
Fossil stays of Llukalkan and Viavenator have been discovered simply 700m aside within the Bajo de la Carpa Formation, close to the identical well-known fossil website at La Invernada, in Argentina.
“It is a notably necessary discovery as a result of it means that the range and abundance of abelisaurids have been outstanding, not solely throughout Patagonia, but in addition in additional native areas throughout the dinosaurs’ twilight interval,” says lead creator Dr Federico Gianechini, a paleontologist on the Nationwide College of San Luis, Argentina.
Abelisauridae have been a placing household of theropod dinosaurs averaging 5 to 9 meters lengthy that prowled primarily in Patagonia and different areas of the traditional southern subcontinent Gondwana — recognised in the present day as Africa, India, Antarctica, Australia, and South America. Thus far, nearly 10 species of this fearsome predator have been unearthed throughout Patagonia. Whereas abelisaurids resembled T-Rex usually look with tiny stubby arms, they’d unusually quick, deep skulls which regularly bore crests, bumps, and horns, and have been distinctive.
Shifting upright on their hind limbs with big claws that they might have used to stab their prey, Llukalkan had extraordinarily highly effective bites and really sharp enamel with which to tear down their prey whereas transferring quick because of their highly effective hind legs.
The fossilised stays of Llukalkan embody a perfectly preserved and uncrushed braincase. This new species is comparable in lots of respects to Viavenator, besides that it’s smaller, the holes within the cranium by which the veins move are bigger and extra extensively separated from the supraoccipital crest (one of many bones that kinds the braincase), amongst different variations. However the brand new dinosaur’s most distinctive characteristic is a small posterior air-filled sinus within the center ear zone that has not been seen in some other abelisaurid discovered up to now.
It signifies that Llukalkan seemingly heard in a different way to different abelisaurids — most likely higher and just like that of a modern-day crocodile explains co-author Dr Ariel Mendez from the Patagonian Institute of Geology and Palaeontology, Argentina.
“This discovering implies a distinct listening to adaptation from different abelisaurids, and certain a keener sense of listening to,” says Dr Mendez.
Nevertheless it could have lived, the fossil proof of Llukalkan‘s variations means that abelisaurids have been flourishing proper earlier than the dinosaurs went extinct.
“These dinosaurs have been nonetheless attempting out new evolutionary pathways and quickly diversifying proper earlier than they died out utterly,” provides Mendez.
Regardless of their important discovering there may be nonetheless quite a bit to find. “This discovery additionally means that there are seemingly extra abelisaurid on the market that we simply have not discovered but, so we might be searching for different new species and a greater understanding of the connection amongst furilesaurs,” says Gianechini.