Eresus walckenaeri

Velvet spiders (family Eresidae) are bigger spiders. They can be easily recognized from other families of spiders by a typical body shape (shorter legs, elevated frontal part) and eye pattern. Similarly to some other groups of spiders, they are equipped with additional spinning organ: cribellum. Cribellate webbing enhance a capability of a hunt.

Velvet spiders inhabits deserts or semi-deserts, steppes and other dryer biotopes of Old World. The species richest regions are Mediterranean (mainly Northern Africa and Middle-East; genera: Adonea, Dorceus, Eresus, Loureedia and Stegodyphus) and southern parts of Africa (genera: Dresserus, Gandanameno, Paradonea, Seothyra and Stegodyphus). The majority of species lives in nests under stones or in burrows, less often their built nests on vegetation (genus Stegodyphus). The burrows are composed of a dense web. They spend the most of their live in a nest. Mature males leave a burrow and search for females. Males of Velvet Spiders are very colourful, being one of the most beautiful spiders at all. The most of velvet spiders displays some kind of maternal care resulting in matriphagy (the phenomenon when a female is cannibalised by offspring). In terms of spiders they are long-lived, for terrestrial species takes few years to get adult. Stegodyphus grow a bit faster.

Nearly all European species belongs to genus Eresus. Probably due the spectacular coloration of Eresus males they attracted naturalists since old times. As obvious in many groups of spiders or invertebrates, there is still a lot species to discover. There are many complications in eresid systematic. First is the access to material. Mainly mediterrain species are obviously hard to find. Due a hidden life style and a low population density, they are not frequently found in pitfall traps (only adult males, when searching for females). Secondly, taxonomical characters, differing certain species, are very gentle in genus Eresus, discrimination between a variability in single species or unique species characters, is harder than in other spiders. That is why is still a lot of undescribed species even in "well studied countries" of Europe (Řezáč et al. 2008).

In Velvet spiders is still a lot of species waiting to be described, and even new genus Loureedia has been described recently (Miller et al. 2012). Genera: Stegodyphus, Seothyra, Dorceus, Adonea and Paradonea have been revised quite recently (Kraus and Kraus 1990, Dippenaar-Schoeman 1991, El-Hennawy 2002, Miller et al. 2012) but taxonomy of others is mainly understudied. In total there is described about one hundred species of velvet spiders, but the the real species richness can be much higher.