An international team of scientists examined the Atacama Trench in 2018, a vast trench that parallels the Andes Mountains in-depth and stretches along the west coast of South America. The team, including scientists from Newcastle University, used free-falling landers to collect samples from the few deep-sea species congregating around cameras and baited traps. Newcastle University’s two lander systems discovered three different types of hadal snailfish, but one of them stood out from the others.
This small blue fish- seen from about 6,000 to 7,600 m deep, doesn’t look like other hadal snailfish. It has large eyes and striking color- resembling other species of snailfishes that are found living in much shallower waters. To determine where the new species belongs within the snailfish family, the team employed DNA barcoding and the 3D x-ray method known as microcomputed tomography (micro-CT).
To the team’s amazement, the new species appears to be a unique Atacama Trench colonizer. The newly discovered species is a part of the Paraliparis genus. Rarely found deeper than 2,000 m, this genus’ species are notably prevalent in the Southern Ocean in the Antarctic. This is the first instance of this genus being discovered in the hadal zone.
Study lead author Dr. Thom Linley, a visiting researcher at Newcastle University, said: “I find this family of fishes absolutely fascinating. They are not what we expect from deep-sea fish, and I love to show people that the world’s deepest fishes are pretty cute.
“For me to get a camera down to where these animals live, it’s made of thick stainless steel and sapphire glass. It then films these delicate and beautiful animals perfectly adapted to this extreme environment. With an engineering-built force, we can only clumsily visit these animals for a short time.
“We have been wondering for some time what makes this fish so good at living deep. Maybe a series of lucky accidents, a chance fluke, happened in one lineage. Finding this new species tells us that it’s bigger than that. Lightning struck twice, and there is something special about this family.”
“Paraliparis selti provides a fantastic opportunity to explore what allows fish to live so deep. If we only had a single lineage to study, we could never be sure which traits were just part of that lineage and which are the deep-sea secret sauce.”
The new species may have evolved from the cold-adapted species of the Southern Ocean. This little blue fish opens new questions about the relationship between cold temperature and high-pressure adaptation and gives a new understanding of how and when life went deep.