Hapalotremus exilis (Mello-Leitão, 1923) and Hapalotremus muticus (Mello-Leitão, 1923), previously considered as nomina dubia are here revalidated through the examination of the holotypes. Dolichothele Mello-Leitão, 1923 is revalidated and their type species, Dolichothele exilis Mello-Leitão, 1923 is restored. Goniodontium Mello-Leitão, 1923 and Oligoxystre Vellard, 1924 are considered junior synonyms of Dolichothele. Hapalotremus muticus and Oligoxystre caatinga Guadanucci, 2007 are considered junior synonyms of D. exilis. All species of Oligoxystre are transferred to Dolichothele. Cyclothoracoides Strand, 1929, currently a junior synonym of Hapalotremus Simon, 1903, is here considered a junior synonym of Homoeomma Ausserer, 1871.
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.
The genus Magulla Simon 1892 is revalidated and redescribed. The female of the type species M. obesa Simon 1892 is redescribed and the male is described for the first time. Magulla janeirus (Keyserling 1891) is considered a valid species. Magulla symmetrica Bucherl 1949 is transferred to Plesiopelma Pocock 1901, and considered a junior synonym of P. insulare (Mello-Leitao 1923). Additionally, two new species are described from Brazil: M. buecherli n. sp. from Ilhabela, Sao Paulo and M. brescoviti n. sp. from Sao Francisco de Paula, Rio Grande do Sul.
The genus Tmesiphantes Simon, 1892 is revised. The type-species, T. nubilus Simon, 1892, is redescribed and three new species are described from the state of Bahia, Brazil: T. amadoi sp. nov., T. bethaniae sp. nov. and T. caymmii sp. nov. In addition, Tmesiphanthes physopus Mello-Leitão, 1926 and T. minensis Mello-Leitão, 1943 are transferred to Plesiopelma Pocock, 1901. T. chickeringi is considered species inquirenda.
The genus Guyruita gen. nov. and two new species from Brazil are described. Holothele waikoshiemi (Bertani & Araújo, 2005) from Venezuela is transferred here to the new genus. Guyruita gen. nov. differs from the remaining Ischnocolinae by the following features: labium densely occupied by a lot of cuspules (more than 100), intercheliceral intumescence absent, posterior sternal sigilla remote from margin, tarsal claws without teeth, tarsal scopula I-II undivided (tarsus II with a line of sparse setae, which does not divide the scopula), III-IV divided.