Eratigena is a genus of spider in the family Agelenidae. Most of its species were moved from the genus Tegenaria in 2013, of which the genus name is an anagram.[2] Two species that frequently build webs in and around human dwellings are now placed in this genus: the hobo spider (Eratigena agrestis), native to Europe and Central Asia and introduced to North America, and the giant house spider (Eratigena atrica), native to Europe and also introduced into North America.
Description
They are medium to large spiders. Two symmetrical dark bands are present dorsally on the carapace, which can be serrated or reduced, usually to three or four conspicuous triangles. They also have plumose hairs on the carapace, legs, and opisthosoma. Their rows of eyes are only slightly curved in either direction.[2]
Taxonomy
Phylogeny
Species now placed in the genus Eratigena were previously placed in Tegenaria and Malthonica. In 2013, a study was carried out on European house spiders in the "Tegenaria-Malthonica complex". Using both morphological and molecular data, the study found four well-supported clades, one of which constituted a new genus Eratigena, comprising species formerly placed in Tegenaria and Malthonica.[3] The name Eratigena is an anagram of Tegenaria.[4] Some Tegenaria species had previously been separated into the new genus Aterigena, another anagram of Tegenaria.[5]
Although the genera involved in the study were consistently found to be monophyletic, different analyses found different relationships among them.[3] Based on both morphological and DNA data, one hypothesis for the phylogeny of Eratigena and related genera is:[6]
Bolzern et al. (2013) provide a key to the European agelenid genera. Eratigena can be differentiated from Malthonica by the un-notched trochanters on legs III and IV (notched in Malthonica). The genus differs from Tegenaria in the number and size of the teeth on the rear margin of the chelicerae. Eratigena has six or more teeth, with those closer to the body of the spider being smaller. Tegenaria has three to six large teeth, more or less equal in size.[7]
Bolzern, Angelo; Burckhardt, Daniel & Hänggi, Ambros (26 July 2013), "Phylogeny and taxonomy of European funnel-web spiders of the Tegenaria−Malthonica complex (Araneae: Agelenidae) based upon morphological and molecular data", Zoological Journal of the Linnean Society, 168 (4): 723–848, doi:10.1111/zoj.12040
