Never-before-seen vampire squid species discovered in twilight zone of South China Sea

Scientists in China may have identified a newfound species of vampire squid — only the second known species in the world. 

Vampire squid (Vampyroteuthis infernalis) reach lengths of about 1 foot (0.3 meters). Despite their menacing appearance and name, they are deep-sea scavengers and are unlikely to harm anything aside from small invertebrates and in fact usually gravitate toward feces and dead animals.

The species has been found in temperate and tropical ocean environments in many areas of the world.

The only officially recognized species was described in 1903 following a deep-sea expedition led by German marine biologist Carl Chun. A number of additional species were later described but eventually turned out to be members of the same species. 

These supposed newfound species were juvenile forms of V. infernalis, which had very different physical characteristics — the squid grows a second set of fins closer to its head as it matures and its original fins disappear.

Related: Rare video shows elusive deep-sea squid cradling her gigantic, translucent eggs

"Ten synonymous species that had previously been described showed some morphological differences in their various life stages," study lead author Dajun Qiu, a marine biologist at the South China Sea Institute of Oceanology, told Live Science.

Now, in a new study that appeared on May 2 in the preprint journal BioRxiv, researchers have described a second species of vampire squid found in the South China Sea, near Hainan island, China, in 2016, which they named V. pseudoinfernalis. It was found around 2,600 to 3,300 feet (800 to 1,000 meters) below the sea surface, in the so-called twilight zone, where little light from the surface penetrates.

This newly identified species displays some unique characteristics that distinguish it from V. infernalis. For example, the position of two photophores — light-producing organs — located between its fins and tail are different. In V. infernalis, they are located a third of the way between the fins and the end of the body, while in V. pseudoinfernalis they are located roughly halfway between these points. V. pseudoinfernalis also has a pointed tail while V. infernalis does not have one at all. The newfound species also has a beak with a longer wing on its lower jaw. 

In photographs of the preserved specimen, it looks like a black, gelatinous blob — but in its deep-sea environment it likely shares the billowing, cloak-like form of its cousin.

Genetic analysis further suggests that V. pseudoinfernalis is a distinct species, Qiu noted.

"We will analyze more specimens to ensure that observed morphological differences are consistent in the future," Qiu said. It seems likely that its diet is similar to its better-known relative, but research is ongoing, he said.

While the order Vampyromorphida contains only V. infernalis and the proposed V. pseudoinfernalis, numerous extinct relatives exist in the fossil record. A newfound species, unearthed in Luxembourg in 2022, was preserved with fish clasped in its tentacles, according to a 2024 paper.