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°03.7'S 141°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. Ẕomet Zohar; 31°08.5'N 35°21.6'E) and R. nettae sp. nov. (Israel. Ẕomet Zohar; 31°08.5'N 35°21.6'E). A fourth new species is described in the subgenus Risa: R. (Risa) kotrbae sp. nov. (Israel. Ẕomet Zohar; 31°08.5'N 35°21.6'E).