Three Primitive Arthropod Species Discovered

Three new collembolan species have been discovered in the Maestrazgo caves in Teruel, Spain. This discovery was made by a team of scientists from the University of Navarra and the Catalan Association of Biospeleology.

The scientists reported that these newly discovered minute animals are arthropods from the hexapod group (meaning six legs), a parallel group to insects and one of the most ancient animal species on planet.

These arthropods are slightly different from the hexapod and more primitive, showing absence of wings, different structure of mouth, presence of the ventral organ and frequently, presence of the springing organ named the furca that is an abdomen appendix.

A team of speleologists headed by Floren Fadrique from the Catalan Association of Biospeleology found these animals. They entered different caves in harsh climatic conditions. The caves are at a high altitude, dark with very cold temperatures.

Located in the region of the Iberian Range, the Maestrazgo caves in Teruel are in a very isolated region at an average altitude between 1,550 m and 2,000 m. Its climate can be described as "almost extreme" experiencing temperatures of between -40 degree C and -25 degree C. The temperatures inside the caves remain constant between 5 degree C and 11 degree C.

"Studying fauna in the caves allows us to expand on our knowledge of biodiversity. In the case of the three new collembolan species that we have found in Teruel, they are organisms that have survived totally isolated for thousands of years. Having 'relatives' on the surface means they act like relics from the past that have survived the climate change taken place on the outside of the caves," explained Enrique Baquero, who carried out a taxonomic study along with Rafael Jordana, both of whom are from the University of Navarra.

It is crucial for these scientists to learn how the new-found species adapt to the cave environments.

"Like other cave-adapted animals, the collembolans require greater chemical sensitivity as they cannot use their sight in the absence of light," said Baquero.

The newly discovered species belong to a different group and are phylogenetically separate from one another. The team has named them as 'Pygmarrhopalites Maestrazgoensis', 'P. Cantavetulae' and 'Oncopodura fadriquei'.

Apart from these three, five other new species have already been documented from surrounding caves.

"The animals were captured by laying down traps. These consisted of jars containing different liquids, which the animals approached in search of food. They were then trapped until the speleologists returned to collect them. Professor Jordana and I received the samples collected by the speleologists and proceeded to their identification," said Baquero.

The three new species of collembolan are documented in the investigation published in the Zootaxa journal.