A new genus of minute Sparianthinae spiders from the Caribbean (Araneae, Sparassidae).

The monotypic genus Diminutellagen. n. is proposed to include the type species, Diminutella cortinasp. n., described from San Diego de los Baños, based on male and female specimens. This species is amongst the smallest Sparianthinae known to date reaching only 4.4 mm body length. It can be distinguished from other Sparianthinae by the combination of eye arrangement, with anterior eye row recurved, posterior eye row straight, spination pattern of legs I-II, with three ventral pairs on tibiae and one on metatarsi, and by the peculiar genitalia, with male palps bearing a large, laminar, layered conductor that rests within a retrolateral depression in the cymbium, and a female vulva with long copulatory ducts coiled around the stalk of a globose blind ending appendage.