Systematic revision and phylogeny of the South American sun-spider genus Gaucha Mello-Leit?o (Solifugae: Mummuciidae),with description of four new species and two new generic synonymies

摘要

The South American sun-spider genus Gaucha Mello-Leit?o, 1924 is herein studied from a combined approach of cladistics and traditionaltaxonomy. This is the frst cladistic analysis for a group of mummuciid solifuges, and it is pioneer in integrating traditional morphologicalcharacters with landmark data for inferring the phylogeny of any group of Solifugae. As a result, Gaucha is redefned and its monophylydemonstrated. Gaucha fasciata Mello-Leit?o, 1924, type species of this formerly monotypic genus, is redescribed based on specimensfrom the type locality, in Rio Grande do Sul, Brazil. Three new species are described from Brazil: Gaucha avexada sp.nov. from Bahiaand Tocantins, Gaucha curupi sp.nov. from Rio Grande do Sul, and Gaucha eremolembra sp.nov. from Minas Gerais. A fourth new species, Gaucha casuhati sp.nov., is described from Buenos Aires province, Argentina. In addition, Metacleobis Roewer, 1934 and GauchellaMello-Leit?o, 1937 are synonymized with Gaucha, following the examination of the type specimens and based upon evidence from thecladistic analysis. Gaucha fulvipes (Roewer, 1934) comb.nov., from Mato Grosso (Brazil), is therefore proposed, whereas Gaucha stoeckeli Roewer, 1934 comb.rest., from Luribay (Bolivia), is restored into its original name combination. Gaucha ibirapemussu (Carvalho etal., 2010) comb.nov. and Gaucha mauryi (Rocha, 2001) comb.nov., from the Brazilian states of Piauí and Bahia, are also transferred, fromMummucia Simon, 1879. Gaucha is here defned, among other characters, by the large size of the cheliceral movable fnger MP tooth ascompared to MM tooth, and by the presence of a pronounced gnathal edge carina on the movable fnger mucron of males. Two speciesgroups are herein defned within the genus: the fasciata group, for G. casuhati sp.nov., G. curupi sp.nov., G. fasciata, G. fulvipes comb.nov. and G. stoeckeli comb.rest., and the ibirapemussu group, for G. avexada sp.nov., G. eremolembra sp.nov., G. ibirapemussu comb.nov. and G. mauryi comb.nov. A key to the identifcation of Gaucha species is included.