It is very similar to the genus Thwaitesia, and both are similar to Episinus. Unlike Argyrodes, they have two setae in place of a colulus.
Specimens of S. flavidus are variable in structure. Only some have an elevated eye region or humps on the anterior of the abdomen.
Females of S. gracilis are 3.7mm long, males 2.3mm.
A revision of the genus by Ingi Agnarsson [nl] and colleagues printed in 2018 included the description of fifteen new species, as well as the removal of S. argenteus.[3] Some of the new specific names were named in honor of political figures, artists, and celebrities.[4] As of 2017, when the electronic pre-print was published, Spintharus was the spider genus with the most species named after celebrities.[5]
An earlier revision of the genus was by Herbert Walter Levi; his taxonomy recognized two species: S. flavidus and S. gracilis.[6][7]
Species
As of 2020[update], the World Spider Catalog (WSC), largely following Agnarsson and colleagues, accepts the following extant species:[3][1]
^ abcAgnarsson, Ingi; Van Patten, Chloe; Sargeant, Lily; Chomitz, Ben; Dziki, Austin; Binford, Greta J. (2018). "A radiation of the ornate Caribbean 'smiley-faced spiders', with descriptions of 15 new species (Araneae: Theridiidae, Spintharus)". Zoological Journal of the Linnean Society. 182 (4): 758–790. doi:10.1093/zoolinnean/zlx056.