A new species of deep-sea shark with bright white eyes has finally been identified decades after a dead pregnant female of the species was first spotted off the coast of Western Australia. The ghost shark was initially misidentified and associated with a new species after scientists looked at its strange eggs that had been in museums for years.

The newly discovered species described in a new study published in Journal of Fish BiologyIt was named Apristurus ovicorrugatus, derived from the Latin words “ovi” and “corrugatus” meaning “corrugated”, referring to the corrugated egg case that led to the discovery of the species. In addition to its unique eggs, A. ovicorrugatus also has unusual, bright white eyes.

“This is not a common feature for deep-sea species and only one other species, Apristurus nakayai from New Caledonia and PNG [Папуа-Нова Гвінея]”He has that trait,” said study lead author Will White, an ichthyologist at the Commonwealth Scientific and Industrial Research Organization (CSIRO).

Apristurus is a breed of cat shark. They are commonly known as ghost or demon cat sharks. It is one of the most diverse shark breeds in the world, with about 40 known species.

Most shark species give birth at a young age, while the rest spawn, that is, they lay eggs. Also known as mermaid purses, egg cases often have long tentacles that allow them to cling to algae or rocks. In 2011, researchers stumbled upon an extremely strange bag containing an egg containing a shark embryo. It was clear that the shark belonged to the genus Apristurus, but the eggshell did not match any known species.

For more than a decade, the status of the eggs remained a mystery until scientists found two more eggs in the Australian National Fish Collection run by the CSIRO.

“The eggshells had very prominent longitudinal ridges on the surface that are T-shaped in cross section,” said White. “Another species in the world has eggs with this protrusion shape, and it’s a completely different breed.”

White and colleagues then scoured collections databases to see if other unidentified specimens of Apristurus were found in the small area where the egg sacs were collected. They eventually found a pregnant female: a 46.7-centimetre-long shark that was mistakenly identified as the South Chinese catfish (Apristurus sinensis).

The female carried an egg sac, matching the one she had found ten years ago.

“Fortunately, the female specimen we found contained an egg-shaped shell with the same ribs and confirmed our suspicions,” said White.

The researchers say the discovery of A. ovicorrugatus highlights the importance of eggshell shape in species identification. In Australia, the public is encouraged to upload images of the eggs to a global database, allowing scientists to better understand where egg-laying sharks spawn. The finding of A. ovicorrugatus eggs attached to corals suggests that the species may rely on these organisms for reproduction.

In the future, White and his colleagues look for new species in museum collections to see what else curators have missed or misidentified.