Nemesiidae
Acanthogonatus francki
Brown trapdoor spiders ( Nemesiidae ) are a family of spiders within the subordination of the bird arachnids. Currently, 339 species have been described in 41 genera worldwide.
Appearance and behavior
Like all spiders have mygalomorphen the brown trapdoor spider a stocky physique with strong legs. The coloration is usually a lighter or darker brown. A drawing is usually inconspicuous brown or missing. The chelicerae are strong, and the base member is directed to the front.
Brown trapdoor spiders have in contrast to the authentics trapdoor spiders adhesive hairs ( Scopula ) on the tarsi, which allows them to run up relatively well even on vertical flat surfaces.
The representative of the family dig a burrow in the ground and clothe them with spider silk. The opening of the tube they close with a lid made of spider silk and material from the environment. Thus, the tubes are particularly well camouflaged. The cover, the " trapdoor " is constructed differently in different species. In some, it is a rigid hinged lid, in other species, a thin web, which is inserted as a sliding cover on the opening of the tube.
To hunt the animals lurking in their tube with half-open trapdoor. The front legs are stretched out from the tube and take vibrations of the soil by prey animals perceive. If a prey passes close enough to the tube, the spider jumps out of hiding out, seizes and overwhelms the prey, carries them immediately back into the tube and eaten it there.
Some types improve their perception of the vibrations in that they attach signal threads around the tube or spin parts of plants around the tube edge.
Dissemination
Brown trapdoor spiders do not occur in Central Europe. Several species of the genera Brachythele, Iberesia, Nemesia and Spiroctenus, however, are common in the Mediterranean and South East Europe.
Genera
The genera of the brown trapdoor spiders are: