Scientists working on the Ashmore Reef in Western Australia were the first humans to see a short-nosed sea snake in more than two decades last week. The reptiles, which are olive-colored and highly endangered, have been considered extinct in the region for 23 years.

Deadly Sea Snake

The short-nosed sea snake (Aipysurus apraefrontalis), like cobras, taipans, and death adders, belongs to the Elapidae tribe, which means it has short, hollow fixed fangs capable of injecting primarily neurotoxic venom.

In short, it's not an animal you like to come across when swimming. According to ABC Science, the scientists were secure inside a research vessel "fitted with sophisticated robotic capabilities" when they were discovered.

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Accidental Discovery

"They were staring at a dead shell that [the researchers] were attempting to pick up, and it had a sea snake lying next to it," said Blanche D'Anastasi, a sea snake specialist at the Australian Institute of Marine Science. "They asked to zoom in on it, and [both] recognized it as a short-nosed sea snake right away. Soon after, they called me and said, 'Is this what we think it is?'"

Much to her delight, it was. According to D'Anastasi, short-nosed sea snakes were once plentiful on Ashmore Reef, but their numbers started to decrease in the 1970s and peaked in the early 2010s. Sea biologists are concerned about the downward trend.

"If you were exploring the reef site, you'd see maybe 50 snakes a day," D'Anastasi said. "By 2002, the number of snakes a day had dropped to 20. By 2010, it had dropped to 10, and by 2012, there were no snakes left in the shallows."

When the species vanished from Ashmore in 1998, it was thought to be extinct. In 2016, Kate Sanders, a reptile ecologist at the University of Adelaide, and her team discovered a few remote, scattered colonies coast.

"We've seen a single organism from Cable Beach in Broome and dispersed distributions from the Exmouth Gulf," she said.

Doubts About the Species

However, their representatives were different from the creatures previously seen on the reef in many respects, creating the likelihood that they were a very other species of sea snake. Their heads are smaller, for instance.

It's difficult to tell if the latest specimen is a coral snake or a coastal snake based on photographs. It was discovered rolled up on the seabed some 220 feet under the surface in the ocean's twilight zone. The twilight zone, not to be confused with the 1960s sci-fi show of the same name, refers to the region of the sea that gets very little sunshine.

How they Might Have Survived

According to Sanders, the position indicates one of two scenarios. In the first case, the original short-nosed sea snakes have been living on the coral for a long time, at distances outside human control. The coastal snakes have simply extended their territories in the second.

"Is it possible that they recolonized from the coast? That is an extremely significant issue," Sanders stated his opinion. "If the coastal population recolonizes, it suggests that we've missed the historical richness that used to exist on Ashmore."

Testings will soon be conducted.

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