In March, Kat Bolstad returned from an Antarctic expedition where she had used a new camera system specially built to search for the elusive colossal squid.

No one had captured footage of one of these animals swimming in the deep sea. She didn’t spot one on this voyage either.

On the day she left the ship, though, Dr. Bolstad, a deep sea cephalopod biologist, learned about a recent video taken on March 9 from the South Sandwich Islands. A team searching for new marine life and remotely using a Schmidt Ocean Institute submersible, had happened upon a young cephalopod, and people wanted Dr. Bolstad’s help identifying it.

The juvenile was about 30 centimeters long (a little less than a foot), with a transparent body, delicate arms and brown spots. It was a colossal squid.

“Pretty much as soon as I saw the footage, I knew there was a good chance,” Dr. Bolstad, a cephalopod biologist at the Auckland University of Technology in New Zealand, said. She consults remotely for Schmidt’s Antarctic work.

It’s been 100 years since the colossal squid was formally described in a scientific paper. In its adult form, the animal is larger than the giant squid, or any other invertebrate on Earth, and can grow to 6 or 7 meters long, or up to 23 feet.