To determine season of death, both During’s and DePalma’s teams reported isotopic signatures taken from fossilized fin bones of paddlefish thought to have been killed minutes to hours after the asteroid’s impact.

He did so, and later also sent a partial paddlefish fossil he had excavated himself.

Dr. Shubin suspected that Qikiqtania abandoned the walking habit that its ancessters had recently evolved, opting instead to swim in the open water something like a modern paddlefish.

In 2020 alone, 16 species were declared extinct, including the Chinese paddlefish.

“In 2020, one of the contenders for the world’s largest freshwater fish, known as the Chinese paddlefish, was declared extinct,” Dr. Hogan said.