Weird demon shark with bright white eyes discovered off Australia

More than ten years after the first mysterious egg cases were discovered in a collection of Western Australian museum artifacts, the shark Apristurus ovicorrugatus was named as a new species.

After years of collecting a dead pregnant female of the species off the coast of Western Australia, a new species of deep-sea shark with dazzling white eyes has finally been named. The "ghost" shark's unusual egg casings, which had been languishing in museum storage for years, forced experts to reassess their initial identification of the animal.

Apristurus ovicorrugatus is the name given to the newly discovered species, which was described in a new study that appeared in the Journal of Fish Biology on April 23. The name is derived from the Latin words for egg and corrugated, which refer to the species' corrugated egg cases.

A. ovicorrugatus also has striking, shining white irises in addition to its distinctive egg casings.

According to study lead author Will White, an ichthyologist with the Commonwealth Scientific and Industrial Research Organization (CSIRO), "this is not a common feature for a deepwater species and only one other species, Apristurus nakayai from New Caledonia and PNG [Papua New Guinea] shares this character."

Catsharks belong to the genus Apristurus. Common names for them include ghost catsharks and devil catsharks (opens in new tab). With over 40 species now recognized, it is one of the most varied genera of sharks in the world.

The rest of the shark species are oviparous, which means they lay eggs, while the bulk of shark species give birth to live offspring. The mermaid's purse-like egg casings frequently feature lengthy tendrils that enable them to cling to rocks or seaweed.

Researchers discovered an extraordinarily bizarre egg case(opens in new tab) in 2011 that contained a shark embryo. The egg case did not match any known species, yet it was obvious that the shark belonged to the genus Apristurus.

The mystery surrounding the egg case persisted for more than a decade until researchers discovered two more eggs in the Australian National Fish Collection, a division of the CSIRO.

According to White, "the egg cases had very distinctive longitudinal ridges on their surfaces, which were T-shaped in cross-section." Only one other species in the world—and it belongs to a completely different genus—has been discovered to have egg casings with that type of ridging.

To determine if any further unidentified Apristurus specimens had been discovered in the limited area where the egg cases had been gathered, White and his colleagues next searched through their collection database. A shark measuring 1.5 feet (46.7 cm) long that had first been mistaken for a South China catshark (Apristurus sinensis) was discovered to be pregnant.

The female was carrying a single egg case that was identical to the one they had discovered ten years before.

We were fortunate to find a female specimen that had an equally ridged egg case, which proved our concerns, White added.

The finding of A. ovicorrugatus, according to researchers, emphasizes the value of species identification based on the structure of the egg case. To help scientists better identify where egg-laying sharks are reproducing, the public is asked to contribute pictures of egg cases to a worldwide database in Australia. Due to the fact that the egg cases for A. ovicorrugatus were discovered linked to corals, it is possible that this species depends on corals for reproduction.

White and colleagues are currently searching museum collections for new species to discover what else curators may have missed or incorrectly recognized.