Spiders rank seventh in global diversity and are an important predatory group of terrestrial animals. Presently about 40 000 species have been described globally and this is estimated to increase to 170 000. South Africa has a rich fauna and 67 families are known from the region.
The taxonomic information on most families from South Africa is still rudimentary, and only 91 genera (19 %) have been revised while 2% of the genera are monotypic. A breakdown of these revisions indicated that on average between 20-25% of the species are new and 8 % are new synonyms.
Spiders are predators and they play an important role in biological control in agro-ecosystems, while a few species are of medical importance to man.
Although spiders are absent from the majority of Red Lists this does not mean that they are less threatened by human activities. Spiders are wingless animals and frequently have a high bio-indicative value as they are usually more strongly associated with a biotope than flying insects. Spiders of the suborder Mygalomorphae, and especially the larger baboon spiders of the family Theraphosidae, are classified as Commercially Threathened in terms of the IUCN system, owing to their demand for pets. In South Africa the larger Theraphosidae genera were added to Schedule VII of the Transvaal Provincial Nature Conservation Ordinance of 1983 as Protected Invertebrate Animals.