Lizard-Like Fossil May Represent 306-Million-Year-Old Evidence of Animal Parenting
By Katherine J. Wu/SmithsonianMag.com
The first fossil was so stunning that Brian Hebert nearly missed the second.
Tucked into the stump of a 300-million-year-old tree was a neat line of vertebrae, sprouting a series of delicate, wispy ribs. A smattering of belly scales freckled the space below, paving a path to a pelvis and a pair of petite thigh bones. These were the first known remains of Dendromaia unamakiensis, an early land-dwelling vertebrate that likely resembled a foot-long monitor lizard.
“I can close my eyes and remember it like it was yesterday,” says Hebert, an amateur fossil hunter who happened upon the tree in Cape Breton, Nova Scotia, in 2017. “It was three dimensional, right in front of my face.”
Then Hebert spotted another set of bones that stopped him dead in his tracks: a tiny, inch-long skull, nestled into the space where a left femur met a pubic bone. This skull, Hebert realized, belonged to a juvenile, curled up against what was probably its mother.
Hebert didn’t know it at the time, but what he found would soon become the prime piece of evidence in a paper published today in the journal Nature Ecology & Evolution arguing that parental care—investing resources in offspring after birth—is at least 306 million years old.