In this study the Brazilian Amazonian species of Acanthoscurria Ausserer, 1871 are redescribed: A. geniculata (C.L. Koch, 1841), A. tarda Pocock, 1903, A. juruenicola Mello-Leitão, 1923, A. theraphosoides (Doleschall, 1871). Acanthoscurria simoensi Vol, 2000 and A. insubtilis Simon, 1892, previously known from French Guyana and Bolivia, respectively, are recorded for Brazil by the first time. The females of these two species are described for the first time and a new species, A. belterrensis sp. nov., is described from Belterra, Pará, Brazil. In addition, four synonymies are established: A. transamazonica Piza, 1972 as junior synonym of A. geniculata; A. ferina Simon, 1892 and A. brocklehursti F.O.P.-Cambridge, 1896 of A. theraphosoides; and A. xinguensis Timotheo da Costa, 1960 of A. juruenicola. Acanthoscurria belterrensis sp. nov. resembles A. gomesiana Mello-Leitão, 1923 by the color pattern and structure of sexual organs. The male can be distinguished by the less curved embolus and the very projected prolateral superior and prolateral inferior keels, giving a triangular aspect to the basis of embolus, and the female seminal receptacles presenting a larger and narrower basis.

Acanthoscurria natalensis Chamberlin, 1917 is redescribed. The following species are considered junior synonyms of A. natalensis: A. cursor Chamberlin, 1917, A. fracta Chamberlin, 1917, A. rondoniae Mello-Leitão, 1923, A. chiracantha Mello-Leitão, 1923, and A. parahybana Mello-Leitão, 1926. All examined specimens, including the types, share the same general aspect, morphology of the sexual organs, color, and measurements. Acanthoscurria natalensis resembles A. paulensis Mello-Leitão, 1923 and A. chacoana Brèthes, 1909 in the general aspect, size, and by the morphology of the sexual organs: male palpal bulb with embolus ending like a shell, due to the prolateral and superior keels. It can be distinguished from these two species by the less developed keels and the longer embolus. The female resembles A. paulensis and A. chacoana by the fused base of the spermathecae and differs by the more evident lobes, projected from base. The distribution of A. natalensis is expanded to Brazilian states covering the Caatinga and the Cerrado biomes

The male of Acanthoscurria paulensis Mello-Leitão, 1923 is redescribed and the female is described for the first time. The male holotype, from Pirassununga, state of São Paulo, Brazil, could not be located and the redescription is based on specimens collected in the type locality. Acanthoscurria atrox Vellard, 1924 is considered a junior synonym of A. paulensis based on their original descriptions and figures of the male palpal bulb, and also supported by the study of several specimens from both type localities, Pirassununga and Campo Grande, state of Mato Grosso do Sul, Brazil. Acanthoscurria guaxupe Piza, 1972 is also considered a junior synonym of A. paulensis based on examination of the holotype. Acanthoscurria paulensis resembles A. chacoana Brèthes, 1909, A. juruenicola Mello-Leitão, 1923, and A. geniculata (C.L. Koch, 1842) by the large size (over 50 mm). The male of A. paulensis resembles that of A. chacoana,A. juruenicola, and A. geniculata by the aspect of the palpal bulb with an embolus ending like a shell, due to the well-developed prolateral inferior and superior keels. It can be distinguished from A. chacoana by the palpal bulb less compact and with a longer embolus and from A. juruenicola and A.geniculata by the absence of a third accessory keel. The female resembles A. chacoana,A. juruenicola, and A. geniculata by the fused base of the spermathecae, and differs by the square or slightly wider than longer base of the spermathecae and by the terminal lobes directed towards each other. New distribution records for A. paulensis are provided from the Brazilian states of Mato Grosso, Goiás, Minas Gerais, Mato Grosso do Sul, Espírito Santo, Paraná, and Rio Grande do Sul.