| Abstract: | The mite genus Erythracarus is revised and redefined and the new pyrrholeucus species group is described. The type species of Erythracarus is established as E. ruricola and the previous designation of Trombidium parietinum as the type is thus declared invalid. Bechsteinia and Chabrieria are newly synonymized with Erythracarus. Nine new species are described: Erythracarus amnicolus n. sp., E. avius n. sp., E. barbarus n. sp., E. ciliatus n. sp., E. decoris n. sp., E. elegans n. sp., E. flavipes n. sp., E. katherinae n. sp. and E. nasutus n. sp. The species E. parietinus, E. pyrrholeucus, E. festinus and E. grahami are redescribed and identification keys to known species and instars of Erythracarus are presented. E. cluozzai is made a junior synonym of Tarsolarkus articulosus, Bechsteinia solarii and Erythraeus spinatus are made junior synonyms of Erythracarus parietinus, while Bechsteinia californica, B. schneideri and Tarsotomus terminalis are all made junior synonyms of E. pyrrholeucus. E. simku is found to be a nomen nudum. E. pyrrholeucus is recorded for the first time from Australia, Iran and the Ukraine and E. parietinus for the first time from the western United States. The only record of E. parietinus from Australia is shown to be based on a misidentification. Observations on reproductive behaviour are made for five Erythracarus species. All of these reproduce sexually by means of stalked spermatophores, the shape of which is species specific. Spermatophores are often deposited on top of one another, possibly indicating sperm competition. Males of one species, E. pyrrholeucus, are unknown and this species is thus likely to be thelytokous. Some Erythracarus species are oviparous. E. ciliatus and E. parietinus are ovoviviparous or viviparous. Prelarvae that were studied were immotile except for those of E. ciliatus, which were able to move their legs. Immotility is a derived character state in Erythracarus and possibly an adaptation to more protected habitats. |
