The Neotropical crab spider genera Tobias Simon, 1895 and Epicadus Simon, 1895 comprise species with remarkable somatic morphology and confounding taxonomic history. The results of our recent cladistic analysis corroborate and extend preceding taxonomic assumptions in showing that Tobias is a junior synonym of Epicadus. In the present paper the six species recently transferred from Tobias to Epicadus are redescribed. Two new species are described based on both males and females: Epicadus dimidiaster sp. nov. and Epicadus tigrinus sp. nov.; the male of Epicadus granulatus Banks, 1909 is described for the first time. The diagnosis of the genus is revised, an identification key is provided, and information on geographical distribution is updated. Epicadus now comprises eleven species.

The present paper presents a cladistic analysis of the spider genus Tobias Simon, 1895. The analyses were based on a matrix with 29 terminal taxa scored for 86 morphological characters, with a dataset tested under two methodologies for character weighting (i.e. equal and implied weighting). Both analyses supported the paraphyletic relationship of Tobias with Epicadus Simon, 1895, with the former considered a junior synonym of the latter (new synonymy). Onocolus, Epicadinus and Epicadus form a clade supported by two synapomorphies, corroborating previous taxonomic assumptions regarding the proximity of these genera. Epicadus has two lineages: the ‘pustulosus clade’, comprising bark-like individuals that camouflage themselves on tree trunks and branches, and the ‘heterogaster clade’, which consists of a group of spiders that present a wide range of polychromatism and use flowers as hunting sites. Synonymies are presented and a new combination for all species previously assigned as part of Tobias is proposed. Epicadus now comprises nine species.

Here we present a revision of the Australian species of Stephanopis. The type species S. altifrons is redescribed and S. aspera, S. depressa, S. monticola, S. elongata and S. scabra are considered its junior synonyms. Males of S. altifrons, S. angulata, S. nigra, S. armata, S. fissifrons and S. longimana are described for the first time. We propose neotypes for S. nigra and S. barbipes and describe the female of the latter. Nine species are considered species inquirendae, S. thomisoides as nomen dubium and S. cheesmanae is transferred to Phrynarachne. Seven new species are described, new distribution records are provided and comments are made about the validity of the genus and its relationship with Sidymella species and other Stephanopinae genera from the Australian region.

All species of Epicadus Simon, 1895 are reviewed and redescribed, including the previously unknown males of E. rubripes Mello-Leitão, 1924 and E. planus Mello-Leitão, 1932. A new diagnosis based on morphological characters is proposed for the genus. Three valid species of Epicadus are recognized: E. heterogaster (Guérin-Méneville, 1829); E. rubripes and E. planus. The following taxonomic changes are proposed: E. granulatus Banks, 1909 is considered incertae sedis, most likely belonging to a new genus; E. h. scholagriculae Piza, 1933 is considered a junior subjective synonym of E. heterogaster; E. pallidus Mello-Leitão, 1929 is considered a junior subjective synonym of E. rubripes Mello-Leitão, 1924; E. nigronotatus Mello-Leitão, 1940 is considered junior subjective synonym of E. planus Mello-Leitão, 1932. Species distributions were updated with new records in the Neotropics, including Bolivia, Colombia, Ecuador, Mexico, Panama, Paraguay, Peru and Venezuela, which makes Epicadus a genus of Neotropical distribution.

Four Neotropical species of Sidymella Strand, 1942, S.furcillata Keyserling, 1880, S.longispina (Mello-Leitão, 1943), S.lucida (Keyserling, 1880), and S.kolpogaster (Lise, 1973) are redescribed from both sexes. The holotype of S.nigripes (Mello-Leitão, 1947) is lost and this taxon is considered a species inquierenda. Sidymellaobscura (Mello-Leitão, 1929), S.parallela (Mello-Leitão, 1929), and S.spinifera (Mello-Leitão, 1929) are all nomina dubia. Two new species are described: Sidymellaexcavatasp. nov. (males and females) and S.marmoratasp. nov. (female).

The males of Tobias caudatus Mello-Leitão, 1929 and Tobias pustulosus Simon, 1929 are described for the first time, females are redescribed and both sexes are illustrated. New distribution records are presented for both species. Tobias monstruosus Mello-Leitão, 1929 is considered a junior synonym of T. pustulosus. The types of Tobias albovittatus Caporiacco, 1954, and Tobias gradiens Mello-Leitão, 1929 are lost, and Tobias albicans Mello-Leitão, 1929 and Tobias corticatus Mello-Leitão, 1917 are known only from poorly preserved specimens, thus they all are considered nomina dubia.

A matrix of 117 morphological characters scored for 77 terminal taxa was subjected to parsimony analysis under equal and implied weighting schemes and to Bayesian inference in order to test the relationships in and between Stephanopis and Sidymella species, as well as its implications for the systematics of the subfamily Stephanopinae. A sensitivity test was performed to evaluate nodal stability. Our results indicate the polyphyletism of both genera and the topologies obtained allowed the proposition of the following taxonomic acts: The "altifrons clade" is the only group considered as Stephanopis (stricto sensu), with species restricted to the Australian region; most species from the Neotropical region, hitherto attributed to this genus, formed the well-supported "pentacantha clade", while two of them, restricted to Central America, were recovered as the "championi clade". The latter shows significative evidences for the revalidation of Paratobias gen. rev.; the "cambridgei clade" emerged with I. punctata nested within, having all its component species transferred to Isala. None of the Sidymella species with Australian distribution seems to be part of this genus, which occurs in fact only in the Neotropical region and is closely related to Coenypha. This latter has an increment of three species transferred from Stephanopis. Aside from the "lucida clade", which is considered here as Sidymella (stricto sensu), three other groups and a single species emerged apart from this genus: the "hirsuta clade", "trapezia clade", "angularis clade" and Si. rubrosignata. Morphological evidences seem to justify the proposition of all these groups as new genera.

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.