In 2016, Lida Xing was combing the amber markets of Myanmar when a merchant enticed him over to his booth with what he said was the skin of a crocodile trapped in amber. When Dr. Xing inspected the specimen through its honey-colored encasement and noticed the diamond-shaped pattern of its scales, he realized what he was holding was actually a 99-million-year-old snakeskin .

Dr. Xing, who is a paleontologist from the China University of Geosciences in Beijing, had previously recovered a feathered dinosaur tail and a baby bird in the amber markets. But he said that of the hundreds of thousands of amber pieces discovered in the area, no one had ever before found a snake.

He purchased the snakeskin and set up a meeting with Michael Caldwell, a snake paleontologist at the University of Alberta. A few minutes before Dr. Xing boarded his flight to Canada, a different colleague alerted him to another recently discovered snake specimen that was more amazing than the first: entombed in a silver-dollar-sized chunk of amber was a baby snake.

“The fossil is the first baby snake and the oldest baby snake to yet be found,” said Dr. Xing. Before this finding, paleontologists had not uncovered a fossilized baby snake even in the rock fossil record, said Dr. Caldwell.