‘A Bit Spooky’: the new shark species with bright, white eyes

What has long, bright white eyes, swims the deep waters of Australia and attaches its eggs to coral?

A new shark species, called Apristurus ovicorrugatus.

The discovery process began several years ago, when researchers sifted through uncatalogued material in the Australian National Fish Collection, housed in Hobart, where they found a mysterious egg they couldn’t assign.

That led to a research mission that eventually revealed a new species of demonic catshark.

The researchers announced their discovery in a paper published in the Journal of Fish Biology and titled “Which came first, the shark or the egg?”

The Apristurus genus, the second most diverse group of sharks numbering about 40 species, is commonly known as the ghost or demonic cat shark. The name is based “on the fact that they live deep and are a bit spooky,” said Helen O’Neill, a research technician and one of the paper’s authors. The sharks are bottom feeders and have elongated cat-like eyes.

But something makes the newly discovered species even creepier. These cat sharks have bright white irises, an unusual feature for deep water creatures. Ms O’Neill said she could only theorize why a shark would have such white eyes. They could help them see better in the dark, she said.

Only one other Apristurus catshark has white eyes, but researchers were able to tell a difference between the two similar species because of their egg shells.

The Apristurus ovicorrugatus’ egg cartons have strong T-shaped ridges, the authors said; the name ovicorrugatus refers to these corrugated egg cases. The unique markings were first described by scientists in a 2011 paper, which is also the first recording of the egg cases, but they didn’t have enough evidence to determine it’s a new species.

The egg cartons helped researchers learn that the new species lays its eggs by attaching them to coral, keeping them from being swept away by currents.

Using egg case morphology and other methods, such as studying teeth, scales, genetics and livers, the scientists were able to write and submit a first draft of the study – but it was not accepted because it lacked genetic material, Ms. O’Neill said.

She feared that process could take 20 years. “I could be dead before that happens,” she said.

The researchers needed more evidence, but couldn’t have gotten any genetic material from the original egg case because it had already been preserved and the egg cases themselves also contained too much collagen to properly test.

Then late last year, a research trip off the coast of Western Australia was successful in finding egg cases of Apristurus ovicorrugatus. “That was so lucky,” said Mrs. O’Neill.

Reproduction in sharks varies greatly: some lay eggs while others incubate them internally, and still others give birth to live young. But the Apristurus sex show a way of laying eggs in pairs, one for each ovary, of which these sharks have two. That leads to two egg cartons.

And one of those egg cartons that researchers found had an embryo capable of providing the necessary genetic material.

“This is the last piece of the puzzle,” thought Mrs. O’Neill, “to prove that this is a new species.”