Legend: Mesoamerica = Mexico and Central America Pre-Columbian = Before Christopher Columbus Amerindian = Indigenous Indians of North and South America Paleoindian/Paleoamerican = The original Black settlers of the Americas The discovery of a bird-like dinosaur in South America has paleontologists rethinking when, where and how one group of raptors evolved.
The rooster-sized dinosaur is called Buitreraptor (bwee-tree-rap-tor) gonzalezorum.
Since dromaeosaurs had only been found in places that used to be part of Laurasia, scientists figured that the beasts evolved into being after Pangea split.
As with dromaeosaurs, new discoveries are forcing scientist to re-consider their earlier theories of Human presence in the American hemisphere as well.
The time of the first peopling of Mesoamerica remains a puzzle, as it does for that of the Americas in general.
It has a long head and long tail and wing-like forelimbs.
Its serrated teeth, like steak knives, suggest it was a carnivore.
Here's why that's important: About 200 million years ago, Earth had just one giant land mass called Pangea.
Toward the end of the Jurassic period, it split in two.
Odds being against such striking parallel evolution, paleontologists speculate that dromaeosaurs more likely originated more than 180 million years ago, before Pangaea broke apart.
The newly discovered fossil also shows that the creatures developed slightly different characteristics after they split up.
It has been widely accepted that groups of peoples entered the American hemisphere from northeastern Siberia, perhaps by a land bridge across the Bering straits of Alaska that might have existed then, (This at some time in the Late Pleistocene, or Ice Age).
There is already abundant evidence that by 11,000 B.
Advanced radiometric dating technology allowed scientists to determine the mastodon bones belong to the Late Pleistocene period, or 130,000 years old, with a margin of error of plus or minus 9,400 years."The bones and several teeth show clear signs of having been deliberately broken by humans with manual dexterity and experiential knowledge," Holen said in a press release.