The spider genus Spintharus occurs from the northeastern United States to Brazil. Nicholas Marcellus Hentz circumscribed the genus in 1850, initially as a monospecific genus containing his newly described species S. flavidus.

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 and colleagues printed in 2018 included the description of fifteen new species, as well as the removal of S. argenteus. Some of the new specific names were named in honor of political figures, artists, and celebrities. As of 2017, when the electronic pre-print was published, Spintharus was the spider genus with the most species named after celebrities.

An earlier revision of the genus was by Herbert Walter Levi; his taxonomy recognized two species: S. flavidus and S. gracilis.

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