Two new species in the South American sun-spider family Mummuciidae are herein described. Gaucha ramirezi sp. nov. is known from the Chancaní Provincial Park and Forest Reserve, Córdoba province, Argentina, and further reported for a single locality to the northeast, in Santiago del Estero province. The systematic position of this species is uncertain and it is not assigned to any species-group of Gaucha Mello-Leitão, 1924. The other species, Gaucha santana sp. nov., is only known from the Ibirapuitã Environmental Protection Area, in the southern Brazilian state of Rio Grande do Sul, and is a member of the fasciata species-group. With these descriptions, the number of known species of Gaucha is raised to eleven.

Keywords: Araneae, Solifuges, Chancaní Park and Reserve, Ibirapuitã Environmental Protection Area, Santana do Livramento, taxonomy, DNA barcode

Ricardo Botero-Trujillo, Ricardo Ott, Camilo I. Mattoni, Mónica F. Nime and Andrés A. Ojanguren-Affilastro. 2019. Two New Species of the Sun-spider Genus Gaucha from Argentina and Brazil (Solifugae, Mummuciidae). Zootaxa. 4551(2); 180–194.  DOI: 10.11646/zootaxa.4551.2.3