Revision of the southern Andean genus Sørensen, 1886 (Opiliones, Gonyleptidae, Pachylinae).

Species of the genus Sørensen, 1886 are conspicuous gonyleptids that occur in Chile and Argentina. Here, the genus is revised for the first time and the cladistic analysis based on morphological characters does not corroborate its monophyly unless a phylogenetically unrelated species is excluded (explained further on). A new classification is proposed for the seven species left in the genus and considered valid, of the 13 nominal species previously recognized. Two out of the seven valid species are considered as species inquirendae: (Mello-Leitão, 1945) [= Mello-Leitão, 1945] and (Mello-Leitão, 1943) [= Mello-Leitão, 1943]. The following synonymies are proposed: (Gervais, 1849) [original combination = Gervais, 1849] is a junior synonym of (Gervais, 1847) [= Gervais, 1847]; Roewer, 1913, (Mello-Leitão, 1946) [= Mello-Leitão, 1946] and Sørensen, 1902 are junior synonyms of the valid name (Gervais, 1847) [= Gervais, 1847]; and (Roewer, 1913) [= Roewer, 1913] is a junior synonym of the valid name Kirby, 1819. Soares & Soares, 1949 is not congeneric with Argentinean/Chilean species of the genus according to the cladistic analysis and is here synonymized with (Mello-Leitão, 1923 [= Mello-Leitão, 1923]).