Atomosphyrus Simon, 1902

Atomosphyrus Simon, 1902: 405 (type species by original designation: Atomosphyrus tristiculus Simon, 1902); Galiano 1963b: 305 (redescription of type species and treated as invalid genus by type species inquirenda); Galiano 1966 (revalidation); Richardson 2010; Ruiz & Maddison 2015; Maddison 2015; World Spider Catalog 2017.

Diagnosis. Atomosphyrus resembles Thiodina, Cyllodania, Hyetussa, Arachnomura and Tartamura by having spine-like setae on the anterior surface of male chelicera (Fig. 5B) (hard to see in black species, such as At. tristiculus, without an adequate light and contrast, or without SEM). The genus differs from Hyetussa by the filiform embolus curling around the bulb (see Galiano 1966: figs 5‒6, 15‒16); from Thiodina by the absence of dorsal abdominal pattern (Figs 1A‒1D) (abdomen entirely black in Atomosphyrus); from Arachnomura and Tartamura by having a keel on the anterior face of male chelicera; and from Cyllodania by this keel being strongly modified into a “mastidion” in Atomosphyrus on the proximal portion of male chelicera (Figs 5A‒5C; also see Galiano 1966: figs 10, 12), and by the filiform embolus.

List of species (chronological order):

1. Atomosphyrus tristiculus Simon, 1902 (type species). 2. Atomosphyrus breyeri Galiano, 1966 .