A new species of venomous sea snake mysteriously covered head to tail in spiny scales has been discovered in treacherous seas off northern Australia, a new study says.

Though some other sea snakes have spiky scales on their bellies, "no other [known] sea snake has this curious feature," study leader Kanishka Ukuwela, an ecologist at the University of Adelaide, said by email.

Normally snakes have smooth scales, but each of the newly named Hydrophis donaldi's scales has a spiny projection, he said.

Scientists cruising shallow seagrass beds in the Gulf of Carpentaria (map) recently captured nine of the rough-scaled reptiles.

"The minute the first one landed on the deck, I knew we had something special," study co-author Bryan Fry of the University of Queensland in Brisbane, Australia, said by email. "It was quite unlike any of the sea snakes I have seen."

Each of the specimens was found on the rocky seafloor, a habitat that could explain the new species' uniquely strong scales, Fry noted.

Overall, though, "we don't know why this interesting feature evolved in this species, or what they are used for," study leader Ukuwela said.

Venomous Snake Has Deadly Neighbors

The new Hydrophis—literally "water serpent"—likely eluded notice for two reasons. The species is apparently rare, and it lives in coastal habitats largely avoided by fishers, Ukuwela said. Many Australian sea snake species live in the open ocean and are often accidentally caught in prawn trawls. (See snake pictures.)

Little is known about the yellowish brown reptile, other than that it gives birth to live young and, like nearly all live-bearing sea snakes, is "venomous and potentially dangerous to humans," according to the study, published February 21 in the journal Zootaxa.

Furthermore, venom is just one obstacle to unraveling the new species' mysteries, the University of Queensland's Fry noted.

"Field observations are impossible, because the water is very murky and filled with lots of very large bull sharks and saltwater crocodiles, in addition to [highly poisonous] box jellyfish," he said.

"If we tried to dive there, our life expectancy would be measured in minutes. The only question is which animal would kill us.