Paleontology experts are discussing recent fossils found in Argentina that belonged to the largest megaraptor dinosaur unearthed to date.
Scientists at the Argentine Museum of Natural Sciences “Bernardino Rivadavia” announced the discovery in an April 26 Nature journal scientific report which revealed that the apex-predator measured three stories long from head to tail and weighed about five tons.
Aranciaga Rolando, an Argentine paleontologist who scientifically named the dinosaur “Maip macrothorax,” said megaraptors are a group of flesh-eating giants that roamed what is now South America, according to a May 4, CBS News article.
"When I lifted the vertebra and saw that it had the characteristics of a megaraptor, it was really a huge thrill," Aranciaga said in the same article.
According to the Nature journal scientific report, the first part of the megaraptor’s name, “Maip” comes from an “evil” mythological figure of Patagonia’s indigenous Aonikenk people.
The second part of the name, "macrothorax," is a reference to the dinosaur’s 4-feet-wide chest cavity, according to the same scientific report.
Bradley Buerer, San Jose State geology lecturer who teaches “Age of Dinosaurs,” said the dinosaur is one of the largest animals to exist near the end of the age of dinosaurs - the Cretaceous period.
“The megaraptors, in particular, are claw based predators,” he said in a Zoom call. “So they have really big claws, three fingers and two of them have big claws on them - so they’d be using those claws to tear us apart basically [if the dinosaurs existed today].”
Buerer said when people hear the term “megaraptor” they may think of the velociraptors depicted in the 1993 “Jurassic Park” film.
“That's what the megaraptors were originally thought to be - basically giant versions of those animals,” he said. “But as science progressed and we found more fossils, it turns out that that wasn't the case . . . they're actually not as closely related to the other raptor dinosaurs as we might expect.”
Buerer said scientists have developed different models relating megaraptors more closely to dinosaurs such as the Allosaurus or Tyrannosaurus Rex.
Before the Maip macrothorax’s fossils were discovered, paleontologists already had some knowledge of dinosaurs in the megaraptor family.
The first group of megaraptors was discovered in 1996 in the province of Neuquén, the capital city of Argentina, followed by the discoveries of another group of megaraptors in Australia, Japan and Thailand, according to an April 27 statement by the same Argentine scientists who published the Nature journal report.
Carlie Pietsch, SJSU assistant geology professor, said the Maip macrothorax’s large size represents the diversity and evolution of dinosaurs in the Cretaceous period.
“[Megaraptors] are representing this diversity that is sort of spread out - building all these different ecological niches,” she said. “And so I would say that this megaraptor is representative of this predator that is sort of filling this apex-predator space in South America, [similar to] how we have up the T-Rex here in North America.”
The fossils of Maip macrothorax were found in Estancia La Anita, an area in Argentina’s Santa Cruz Province, according to the same April 27 statement.
Pietsch said areas including South America and China were often overlooked or understudied, which is why new dinosaur fossils are still being discovered in those areas.
“We're still this is sort of the golden age of South American and Asian dinosaurs,” she said. “We have discovered many of the things that we're going to discover in North America though I would not suggest at all that there's not more to find here in North America as well.”
Pietsch said the 1800s were a “golden age” for fossil discoveries in North America because where people chose to look for dinosaurs was tied to colonial history and varying economies.
“The economics of the countries also really drives how much paleontological work there is, which makes sense,” she said. “If you don't have a very strong economy, you're not going to spend a bunch of money digging up dinosaur fossils.”
She said as different world economies developed in Argentina and China, they developed strong research institutions and became centers of new discoveries.
Buerer added that by discovering the Maip macrothorax’s fossils, scientists can better understand the prehistoric period in South America.
He said scientists haven’t found complete fossils of megaraptors yet, but particular parts of the reptile can help piece together information about the dinosaurs.
“[With] this particular discovery, they just have some of the vertebrae of the animal and some of the ribs here and there but no skull or not much of the limbs or anything like that,” he said. “We’re doing the best that we can to puzzle through what these things are and what they would look like – so every new megaraptor discovery helps us to fill in a lot of that information.”
