Phylogeny and Taxonomy of the Risa Genus-group (Diptera: Ephydridae), with Description of a New Genus from Australia

The systematic and somewhat controversial history of Risa Becker is presented, and its relationship with Diasemocera Bezzi (tribe Psilopini, Ephydridae) is documented by morphological evidence and an association with host plants in the family Amaranthaceae. The tribe Risini Papp (as Risidae) is synonymized with Psilopini Cresson. Notorisa gen. nov., from Australia, is described (type species: Notorisa mcalpinei sp. nov.; Australia. Victoria: Big Desert National Park, near Lake Hindmarsh; 36 degrees 03.7'S 141 degrees 54.8'E). Achaetorisa Papp is retained as a subgenus within Risa and includes five species, including two new combinations: Risa brevicornis (Papp) comb. nov., Risa salsolae (Mathis & Zatwarnicki) comb. nov., and two new species: R. brevirostris sp. nov. (Israel. Zomet Zohar; 31 degrees 08.5N 35 degrees 21.6'E) and R. nettae sp. nov. (Israel. Zomet Zohar; 31 degrees 08.5'N 35 degrees 21.6'E). A fourth new species is described in the subgenus Risa: R. (Risa) kotrbae sp. nov. (Israel. Zomet Zohar; 31 degrees 08.5N 35 degrees 21.6'E).