What has long, bright white eyes, swims along the deep waters off Australia, and attaches its eggs to coral?
A new species of shark, called Apristurus ovicorrugatus.
The discovery process began several years ago, when researchers were sifting through uncatalogued material in the Australian National Fish Collection, housed in Hobart, where they found a mysterious egg that they could not attribute.
This led to a fact-finding mission that eventually revealed a new species of demon catshark.
The researchers announced their discovery in an article published in the Journal of Fish Biology and titled “Which came first, the shark or the egg?”
L’Apristure genus, the second most diverse group of sharks which has around 40 species, is commonly referred to as ghost or demon catshark. The name is based “on the fact that they are deep-seated and a bit scary,” said Helen O’Neill, a research technician and one of the paper’s authors. Sharks are bottom feeders and have elongated cat eyes.
But something makes newly discovered species even scarier. These cat sharks have brilliant white irises, an unusual feature for deep-sea creatures. Ms O’Neill said she could only theorize why a shark would have such white eyes. They might help them see better in the dark, she says.
Only one other Apristurus The catshark has white eyes, but researchers were able to determine a difference between the two similar species due to their egg shells.
‘Apristurus ovicorrugatus’ the egg cases have strong T-shaped ridges, the authors said; the name ovicorrugatus refers to these corrugated cardboard egg cases. The unique markings were first described by scientists in a 2011 paper, which is also the first record of egg cases, but they lacked sufficient evidence to determine it was a new species. .
The egg cases helped researchers learn that the new species lays its eggs by attaching them to coral, which prevents them from being swept away by currents.
Using egg morphology and other methods, such as studying teeth, scales, genetics and liver, the scientists were able to write up and submit a first draft of the study – but it didn’t. been accepted because she lacked genetic material, Ms O’Neill said.
She feared the process would take 20 years. “I could be dead before this happened,” she said.
Researchers needed more evidence, but had been unable to obtain genetic material from the original egg case specimen as it had already been preserved and the egg cases themselves also contain too much collagen to be properly tested.
Then, at the end of last year, a research trip off Western Australia managed to find cases of Apristurus ovicorrugatus eggs. “It was so lucky,” Ms O’Neill said.
Reproduction in sharks differs enormously: some lay eggs while others hatch them internally, and still others give birth to live young. But the apriture genus display a pairwise spawning pattern, one for each ovary, of which these sharks have two. This leads to two egg cases.
And one of these cases of eggs found by researchers had an embryo, which was able to provide the necessary genetic material.
“That’s the last piece of the puzzle,” thought Mrs. O’Neill, “to prove that this is a new species.”