A previously unknown species of crustacean and two previously unknown species of annelid worms have been discovered during a cave dive near Lanzarote in the Canary Islands off the coast of northern Africa. The discoveries were made by a team of international scientists and cave divers exploring the Tunnel de la Atlantida – the longest submarine lava tube in the world.

The crustacean belongs to the genus Speleonectes in the class Remipedia, while the annelid worms are members of the class Polychaeta.

The crustacean has been named Speleonectes atlantida, after the cave system in which it lives. It looks a lot like its close relative Speleonectes ondinae which was discovered in the same lava tube in 1985. The two crustaceans may have diverged into separate species some 20,000 years ago after the Monte Corona volcano had erupted, forming the famous six-kilometre long lava tube.

Until quite recently, the class Remipedia was unknown to science. The first member of this class was found in 1979 by divers exploring a marine system in the Bahamas archipelago. Since then, 22 Remipedia species have been named and described. Most of them live in Central America, from the Yucatan Peninsula of Mexico through the north-eastern Caribbean. However, two species are instead found in caves in Lanzarote and Western Australia. The existence of these wayward species puzzles the scientists, since it is assumed that these small eyeless cave-dwellers would not be able to simply swim from the Caribbean to West Africa and Western Australia. One theory suggests that this class might be a very old crustacean group that was already widespread 200 million years ago. If this is true, the two species living off Lanzarote became isolated from the Caribbean group by the formation of the Atlantic Ocean.

As mentioned above, members of the class Remipedia live in dark submarine caves and have no eyes. Instead, they find their way around using long antennae. The heads of these predatory crustaceans are equipped with prehensile limbs and poisonous fangs.

The results of the lava cave exploration will be published in a special issue of the Springer journal Marine Biodiversity in September 2009.

The cave exploration team consisted of scientists from Texas A&M University and Pennsylvania State University in the USA, the University of La Laguna in Spain, and the University of Veterinary Medicine Hannover and the University of Hamburg, both in Germany.