Differentiation among cave populations of the Eukoenenia spelaea species-complex (Arachnida: Palpigradi) in the southwestern Alps

Observations on the habitat and feeding behaviour of the hypogean genus Eukoenenia (Palpigradi, Eukoeneniidae) in the Western Italian Alps

The order Palpigradi includes species characterized by millimetric size and a characteristic flagellum with bristles at the end of the opisthosoma. They represent one of the less well-known and obscure arachnid orders. In this paper, observations were made on the ecology and feeding behavior of species belonging to the genus Eukoenenia Börner, 1901, from the Western Italian Alps. Direct observations and photographic documentation of 141 individuals in their cave habitat, allowed the recording of data on the physical and trophic conditions such as the presence/absence of trophic resources, temperature and relative humidity, of the underground environment in which they were found. Results showed that the species of this taxon are not as rare as previously reported and that their presence is mainly influenced by temperature, relative humidity, trophic resources and the presence of two speleothems: rimstone dams and rafts. The combination of our observations as well as data previously published highlights that the taxon can have predatory and saprophagous feeding behavior depending on the availability of the food resources. This work represents the starting point for a further investigation of the taxon.

Pandora is on Earth: new species of Eukoenenia (Palpigradi) emerging at risk of extinction

In 2008 the change to the Brazilian legislation regarding the use of natural caves has caused an increase in the number of studies on environmental impacts involving caves. The legislation requires the classification of such environments according to their importance, and caves that are not classified highly may be irreversibly impacted. Thus, caves in rocks of high economic interest have been intensively sampled, which has resulted in the collection of several specimens of Palpigradi in them. The Iron Quadrangle (in Minas Gerais state) stands out among these areas as one the most important sources of iron ore in Brazil. Several palpigrades from this region are housed in collections: most of them belong to the edaphic species Eukoenenia ferratilis, and a small portion belong to new species that are morphologically quite distinct from E. ferratilis, with longer bodies and more elongated appendages, indicating the presence of troglomorphisms. Therefore, the present study aimed to describe three new troglobitic species of Eukoenenia, which can be distinguished morphometrically and by means of some qualitative characters. These descriptions are important for the preservation of the caves where they occur, since the presence of troglobitic species increases the relevance of the caves, which have been severely threatened by mining activities.