‘Gargantua' deep-sea creature among new species found in Atlantic. See them

Miami Herald

a day ago

In the depths of the Mid-Atlantic Ridge, underwater volcanoes spew material into the ocean water.
Vents that connect underground rifts to the surface release billowing clouds of black deposits of iron sulfide, earning the moniker 'black smoker chimneys.'
These hydrothermal vent fields are hot, chemically rich and toxic to most forms of life. But, a special few organisms have adapted to call them their home.
Now, two new species found around the black smoker chimneys of the Hydra and Falkor hydrothermal vent fields have been identified — and they're huge.
Researchers operating the remote underwater vehicle SuBastian, from the Schmidt Ocean Institute, and the human-occupied vehicle Nautile, from the French Institute of Research and Exploitation of the Sea, used suctioning tools to collect peltospirid gastropods from the black smokers, according to a study published June 5 in the peer-reviewed Zoological Journal of the Linnean Society.
The peltospirid gastropods, or a family of marine snails found around hot vents, were compared to known species, but their 'very large' size immediately tipped off researchers that they may belong to new species.
Genetic testing confirmed their suspicions, according to the study.
The first new species, Peltospira gargantua, was found on a black smoker chimney in the Hydra field at a depth of about 12,300 feet, researchers said.
With a shell smaller than an inch, the snail is 'very large' compared to others in their genus, researchers said. The shell is 'rather tightly coiled,' and their bodies have 'short, paddle-like' tentacles.
Part of the shell is an 'olive green' color, but the shells are typically 'obscured by dark brown to reddish layers of' mineral deposits, according to the study.
'The head is large, with a thick and broad snout that expands slightly towards the mouth,' researchers said of the snail's body. The animals have no trace of eyes on their external bodies, not uncommon for creatures found in the dark abyss of the Atlantic.
Researchers named the species after Gargantua, a character from the French novels 'The Five Books of the Lives and Deeds of Gargantua and Pantagruel,' stories of a giant king and his son.
'The word Gargantua has since been used to mean 'huge' or 'immense,' as exemplified by the English adjective gargantuan,' according to the study. 'Thus, the species name refers to the very large size of the new species in relationship to other known (relatives).'
The second new species, from a different genus, was named after Gargantua's son, Pantagruel, according to the study.
Lirapex pantagruel is the 'largest of all known Lirapex species, hence the name of a giant is fitting,' researchers said.
The species was found on the black smokers of the Falkor hydrothermal vents at a depth of about 13,000 feet, according to the study.
This species is even smaller, with a shell diameter of about 0.3 inches long, and the shell is 'tightly coiled,' researchers said.
The pantagruel snail is also covered in reddish to blackish material, but has a semi-transparent and greenish hue otherwise.
'The soft parts are overall typical of the genus Lirapex,' researchers said. 'The head is large and without pigmented eyes… The snout is short, flattened, with the mouth opening ventrally. A pair of thin, film-like jaws are present.'
Finding the two new species was a 'surprising discovery,' researchers said, as the areas where they live have only been explored for a few years.
'Hydrothermal vents on the northern (Mid-Atlantic Ridge) have been explored for about four decades. Yet, species of large snails aggregating in conspicuous habitats near hot fluid orifices, such as P. gargantua and L. pantagurel, have remained undiscovered until now,' researchers said. 'It might be that the two new species are present only in Hydra and Falkor EMARK, two vent fields that were found only in 2023.'
The research team includes Chong Chen, Florence Pradillon, Coral Diaz-Recio Lorenzo and Joan Manel Alfaro-Lucas.