The genera Davus O. Pickard-Cambridge, 1892, Metriopelma Becker, 1878, and Schizopelma F. O. Pickard-Cambridge, 1897 are redefined. The genus Acentropelma Pocock, 1901 is removed from synonymy with Stichoplastus Simon, 1903, and the genus Eurypelmella Strand, 1907b is removed from synonymy with Schizopelma F. O. Pickard-Cambridge, 1897 gen. rest. The holotype specimens of Davus fasciatus O. Pickard-Cambridge, 1892, Metriopelma zebratum Banks, 1909, Metriopelma drymusetes Valerio, 1982, Metriopelma breyeri Becker, 1878, Schizopelma bicarinatum F. O. Pickard-Cambridge, 1897, and conspecifics of Cyclosternum pentaloris Simon, 1888 are redescribed. Hapalopus ruficeps Simon, 1891 is removed from synonymy with Cyclosternum pentaloris Simon, 1888 and, along with Cyclosternum fasciatus O. Pickard-Cambridge, 1892 and Metriopelma zebratum Banks, 1909, are transferred to the genus Davus (O. Pickard-Cambridge, 1892) comb. nov. Davus santos sp. nov. is described. Davus ruficeps is regarded as senior synonym of Metriopelma zebratum syn. nov., Metriopelma drymusetes Valerio, 1982 is regarded as junior synonym of Davus fasciatus O. Pickard-Cambridge, 1892 syn. nov. Davus mozinna Estrada-Alvarez, 2014 is regarded as junior synonym of D. pentaloris syn. nov. The specimen of Metriopelma breyeri Becker, 1878 from the Natural History Museum, London, is formally nominated as topotype because the holotype is missing (see Discussion). Metriopelma familiare (Simon, 1889) and Metriopelma ledezmae Vol, 2000 are tentatively transferred to the genus Cyclosternum Ausserer, 1871 comb. nov., while Metriopelma coloratus Valerio, 1982 and Metriopelma variegatus (Caporiacco, 1955) are transferred to the genus Hapalopus Ausserer, 1875 combs. nov. Metriopelma velox Pocock, 1903, Lasiodora trinitatis (Pocock, 1903), and L. trinitatis pauciaculeis (Strand, 1916) are transferred to the genus Pseudhapalopus Strand, 1907a combs. nov. Metriopelma spinulosum O. Pickard-Cambridge, 1899 is transferred back to the restored genus Acentropelma Pocock, 1901 comb. rest. along with Cyclosternum macropus Ausserer, 1875, Schizopelma sorkini Smith, 1995, and Lasiodora gutzkei Reichling, 1997, transferred from Lasiodora Koch, 1850 combs. nov. Hapalopus nigriventris (Mello-Leitão, 1939) is redescribed. Lasiodora tetricus (Simon 1889) is transferred from Lasiodora Koch, 1850 to the restored genus Miaschistopus Pocock, 1897 comb. rest. The genera Neischnocolus Petrunkevitch, 1925, with its single species Neischnocolus panamanus Petrunkevitch, 1925, and Barropelma Chamberlin (1940), with its single species Barropelma parvior Chamberlin and Ivie, 1936, are removed from the synonymy of Lasiodora and restored gen. rest.
The tarantula genus Sericopelma was originally defined based on male specimens, most notably lacking tibial spurs on leg I. Early female specimens were unrecognised as Sericopelma, and typically placed in Eurypelma – a dumping ground for problem specimens. The first females were only later recognised, but authors failed to adequately define female Sericopelma. Here, the holotypes of the Southern-most alleged Brachypelma species, B. embrithes (Chamberlin & Ivie, 1936) and B. angustum Valerio, 1980 were examined, and finding both to possess defining characteristics of Sericopelma were transferred. The taxonomic attributes to define Sericopelma relative to Brachypelma and select other Neotropical genera are discussed, especially for females. As important diagnostic characters for Sericopelma, the single (unilobar) spermathecae
swollen at the apex forming a P-shaped cross-section, metatarsus IV with trace scopula, femur IV with a dense retrolateral pad of plumose hair, plus other attributes. Some past confusion in these characters are clarified and Sericopelma relative to Brachypelma and Megaphobema mesomelas are discussed. Finally recommendations are given about these taxonomic changes for CITES regulations.
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.
A new genus Ami Pérez-Miles is proposed for six new species: A. caxiuana Pérez-Miles, Miglio & Bonaldo, from Caxiuanã National Forest, Pará, Brasil, the type species; A. yupanquii Pérez-Miles, Gabriel & Gallon, from the area of Puyo,
Equador; A. bladesi Pérez-Miles, Gabriel & Gallon, from Isla Colón, Panamá; A. pijaos Jimenez & Bertani, from Ibagué, Tolima, Colombia; A. amazonica Jimenez & Bertani, from Leticia, Amazonas, Colombia; and A. weinmanni Pérez-Miles, from La Azulita, Apure, Venezuela. Avicularia obscura (Ausserer 1875) is transferred to Ami and re-diagnosed.
Diagnostic characters of Ami are the modification of Type I urticating hairs, with unusually longer area b, and one or two subconical processes on retrolateral face of male palpal tibiae. Females of Ami differ further from those of other theraphosid
genera by their highly characteristic spermathecae: paired ventral receptacles attached to an almost discrete, semicircular, sclerotized back-plate.