Background Among the 16 Neotropical genera of Philodromidae, Cleocnemis has the most troublesome taxonomic situation. Remarkable morphological differences among several genera historically said to be related to Cleocnemis denote controversial notions and general uncertainty about the genus identity. Thus, to clarify the genus limits and contribute to the understanding of Neotropical Philodromidae, we conducted a morphological analysis, along with Bayesian Inference and Maximum Likelihood molecular phylogenetic analyses focusing on Cleocnemis and related genera of Thanatinae. All of the 14 species previously placed in Cleocnemis were studied, and eight of them included in the molecular analyses based on fragments of 28S rDNA, histone H3, 16S rDNA, and cytochrome oxidase I (COI). Results Cleocnemis was recovered as polyphyletic. Most of its species are distributed into six lineages allocated into five morphologically recognizable groups: Group I [Cleocnemis heteropoda], representing Cleocnemis sensu stricto and two new junior synonyms, Berlandiella and Metacleocnemis; Group II [Tibelloides bryantaecomb. nov., Tibelloides punctulatuscomb. nov., Tibelloides reimoserinom. nov., and Tibelloides taquaraecomb. nov.], representing Tibelloidesgen. rev., which was not recovered as monophyletic; Group III [Fageia moschatacomb. nov., Fageia roseacomb. nov.], representing the genus Fageia; Group IV [“Cleocnemis” lanceolata]; and Group V [“Cleocnemis” mutilata, “Cleocnemis” serrana, and “Cleocnemis” xenotypa]. Species of the latter two groups are considered incertae sedis. Cleocnemis spinosa is maintained in Cleocnemis, but considered a nomen dubium. Cleocnemis nigra is considered both nomen dubium and incertae sedis. We provide a redelimitation of Cleocnemis, redescription, neotype designation, and synonymy of type-species C. heteropoda. Taxonomic notes on composition, diagnosis, and distribution for each cited genus are also provided. Phylogenetic results support the division of Philodromidae into Thanatinae new stat. and Philodrominae new stat. and suggest expansion of their current compositions. Terminology of genital structures of Philodromidae is discussed. Conclusions Our results bring light to Cleocnemis taxonomy and enhance the understanding of the relationships within Philodromidae, especially through the assessment of neglected Neotropical taxa.

The genus Epicadinus Simon, 1895 can easily be distinguished from the other Neotropical Stephanopines by their abundant and robust setiferous tubercles, topped by elongated macrosetae, which cover most of the tegument. Additionally, the genus can be recognized by a pair of conical ocular mounds above the ALE, the anterior eye row very recurved, posterior one slightly procurved; carapace flattened and without tubercles, and opisthosoma with three conical projections (“tubercles”) of variable size and shape. This work is a taxonomic review of the 12 valid species of Epicadinus as listed in version 19 of the World Spider Catalogue (2018), whose hitherto known distribution included few records from Brazil, French Guiana, Bolivia and Peru, and only one from Mexico. Four valid species are recognized: Epicadinus biocellatus Mello-Leitão, 1929; E. trispinosus (Taczanowski, 1872) [with two junior synonyms E. trifidus (Pickard-Cambridge, 1893) syn. nov. and E. cornutus (Taczanowski, 1872) syn. nov.]; E. spinipes (Blackwall, 1862) [with two junior synonyms E. albimaculatus Mello-Leitão, 1929 syn. nov. and E. gavensis Soares, 1946 syn. nov]; and E. villosus [with two junior synonyms E. helenae Piza, 1936 syn. nov. and E. marmoratus Mello-Leitão, 1947 syn. nov.]. Epicadinus polyophthalmus Mello-Leitão, 1929 and Epicadinus tuberculatus Petrunkevitch, 1910 are transferred to Epicadus. Epicadus polyophthalmus (Mello-Leitão, 1929) comb. nov. is considered a nomen dubium. Epicadus tuberculatus (Petrunkevitch, 1910) comb. nov. is a senior synonym of Epicadus pustulosus (Mello-Leitão, 1929) syn. nov.

Four new species of the orb-weaving spider genus Alpaida O. P.-Cambridge, 1889 from Rio de Janeiro state, Brazil are illustrated and described based on males and females from the following municipalities: Alpaida imperatrix new species (Macaé and Rio de Janeiro); Alpaida imperialis new species (Mendes and Rio de Janeiro); Alpaida marista new species (Mendes and Pinheiral); and Alpaida mendensis new species (Mendes). Furthermore, two new synonymies are herein proposed: Alpaida lanei Levi, 1988 = Alpaida atomaria (Simon, 1895) and Alpaida caxias Levi, 1988 = Alpaida tijuca Levi, 1988, alongside new records for both species and also Alpaida venger Castanheira Baptista, 2015.

Three new species of the six-eyed  haplogyne and ecribellate spiders from the genus Ochyrocera Simon, 1891 are illustrated and described based on males and females from southeastern Brazil: Ochyrocera tinocoi new species (Sooretama, Espírito Santo state), Ochyrocera garayae new species (Linhares and Sooretama, Espírito Santo state) and Ochyrocera itatinga new species (Rio de Janeiro city, Rio de Janeiro state). The new species expand the distribution range of Ochyrocera in Brazil and increase to 50 the total number of species described, from which hitherto 33 species occur in South America, acknowledging the high diversity of the genus for the region.