A Spanish-Russian expedition has identified four new species of animals in a cave in the Abkhazia region, near the Black Sea. It is the deepest cave in the world, at -2,191 meters, and two of the species are the deepest arthropods found on the planet.

The team is formed by researchers Sofía Reboleira, from the University of Aveiro (Portugal), and Alberto Sendra, from the Museum of Natural Sciences of Valencia -in charge of the expedition-; and zoologists Rafael Jordana and Enrique Baquero, from the University of Navarra, who have identified and described the new species.

All of them belong to group of the springtails, very numerous arthropod invertebrates close to insects, arachnids or crustaceans. They are characterized by having an external skeleton and articulated appendages (legs, antennae, etc.), as well as a special organ for jumping called furca. Due to their way of life in the cave, the four new species have specific characteristics developed to survive in extreme subway conditions, such as the total absence of light and little availability food resources.

"In response to these conditions, none of the animals have eyes and they lack pigmentation (color). In addition, one of the species has developed a chemoreceptor - a kind of parabolic antenna Chemistry- that allows it to move in such a complicated environment," explains Enrique Baquero, zoologist, professor at Master's Degree in Biodiversity, Landscapes and Sustainable management at the University of Navarra and one of the authors of the study.

"Recyclers" of the organic subject
The scientific work describing the finding has just been published in the journal TAR (Terrestrial Arthropod Reviews), from publishing house Brill. According to Enrique Baquero, the presence of these species in such a rugged environment is explained by the organic subject :"They feed on the fungi that grow on it, contributing to its decomposition and participating in the network of the stable communities of arthropods that exist in the caves".

Each of the species, whose specimens measure between 1 and 4 millimeters, was found at a certain depth. Their names are Anurida stereoodorata, Deuteraphorura kruberaensis and Schaefferia profundisima. The one that reached the highest subway, Plutomurus ortobalaganensis, was discovered at 1,980 meters below the surface".

The Krubera-Voronya cave is the only cave in the world that is more than two kilometers deep. Despite the numerous expeditions that have entered it, this is the first time that its fauna is described.

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Color infographic (Spanish)

Black and white infographic (Spanish)

Color infographic (English)

Black and white infographic (English)

Photograph by the authors: Doctors in Zoology Rafael Jordana and Enrique Baquero.

More artwork

Interview with Enrique Baquero