The early bird species that outlived the dinos likely survived the extinction event by subsisting on seeds. Photo by Catmando/Shutterstock
TORONTO, April 21 (UPI) -- Birds are the evolutionary successors of the dinosaurs, but the succession was nearly not to be. New research suggests birds have seeds to thank for their modern success.
Most bird-like dinosaur species -- like their larger relatives -- died off during the extinction event that occurred roughly 66 million years ago. Several early bird species, however, survived. Why did these close relatives of feathered dinosaurs outlast their predecessors?
To answer that question, scientists first needed to understand the decline of maniraptoran dinosaurs at the end of the Cretaceous period.
To determine whether these creatures were already in decline or were killed off abruptly, a team of scientists led by paleontologist Derek Larson analyzed 3,104 fossilized teeth from four different maniraptoran families. The fossil comprised a time span of 18 million years.
Consistent variation among the teeth fossils suggest the species enjoyed rich genetic and physiological diversity right up until the end.
"The maniraptoran dinosaurs maintained a very steady level of variation through the last 18 million years of the Cretaceous," Larson, a doctoral candidate at the University of Toronto, said in a news release. "They abruptly became extinct just at the boundary."
Larson and his colleagues then turned their attention to the fossilized teeth of the maniraptoran lineage that produced modern birds. Working backward along the evolutionary timeline, the researchers hypothesized that the last common ancestor between the lineage of bird-like dinos and modern birds would have been toothless, beaked seed eater.
Scientists believe the asteroid apocalypse that snuffed out the dinosaurs put a serious damper on vegetation. Species that relied on leaves and flowers were out of luck, but those that could subsist on seeds had an advantage.
"There were bird-like dinosaurs with teeth up until the end of the Cretaceous, where they all died off very abruptly," Larson said. "Some groups of beaked birds may have been able to survive the extinction event because they were able to eat seeds."
The latest research was published in the journal Current Biology.