Icius minimus

Icius minimus is a jumping spider was first described by Wanda Wesołowska and Beata Tomasiewicz in 2008.[1] It was one of over 500 species identified by Wesołowska during her career.[2] It was allocated to the genus Icius, raised by Eugène Simon in 1876.[3] The genus name is based on two Greek words that can be translated distinct, or special, face.[4] The species name recalls the relatively small size of the male.[5] The genus is a member of the tribe Chrysillini, within the subclade Saltafresia in the clade Salticoida.[6] Chrysillines, which had previously been termed heliophanines, are monophyletic.[6] In 2016, Jerzy Prószyński split the genus from the Chrysillines into a group called Iciines, named after the genus. He stated the split was for practical reasons as Chrysillines had become unwieldy.[7]

Icius minimus is a small spider. The male has a cephalothorax that ranges between 1.5 and 1.8 mm (0.059 and 0.071 in) in length and between 1.3 and 1.4 mm (0.051 and 0.055 in) in width. The oval carapace is a brown and of low height. It is covered in black hairs apart from a few spots made of white hairs. The eye field is darker, particularly around the eyes, which is black. The clypeus is low, with short white hairs. The chelicerae is dark brown and unidentate. There are protruding light hairs on the outside of the chelicerae. The labium is brown with light tips. The oval abdomen is larger that the carapace, between 1.8 and 2.0 mm (0.071 and 0.079 in) long and between 1.1 and 1.2 mm (0.043 and 0.047 in) wide. It is generally brown, lighter to the back end, with a distinctive pattern made up of two narrow white stripes fringed by black lines. The underside is yellow with two darker lines. The spinnerets are brown. The front legs are long and dark brown, while the remainder are yellow. All the legs have brown hairs. The pedipalps are yellow.[5] The embolus and the tibial apophysis, or spike, are short. The tibial apophysis is also shaped like a spatula.[8]

The female is larger than the male, with a cephalothorax that is between 2.2 and 2.3 mm (0.087 and 0.091 in) in length and between 1.6 and 1.7 mm (0.063 and 0.067 in) in width.[5] The carapace is similar in colour, with white hairs on the edge. Compared to the male, the spots are less clear. There is a white cross on the eye field.[8] The abdomen is also larger, measuring between 2.9 and 3.3 mm (0.11 and 0.13 in) long and between 1.8 and 2.4 mm (0.071 and 0.094 in) wide [5] It is generally brown with a pattern consisting of a thick white stripe across the front and two interrupted wide white stripes behind, and a big white patch across the middle.[9] The underside is light apart from three thin brown lines. The spinnerets have more grey in the colouring and the legs are all brown, although the front legs are darker like the male. The epigyne has two round depressions that hide the copulatory openings. The seminal ducts are short and receptacles are elongated. There are accessory glands that also lead to the receptacles.[8]

The species is similar to others in the genus, particularly Icius pulchellus.[10] It can be best distinguished by its colours and the pattern on the abdomen. The male has a distinctive tibial apophysis and the female has longer receptacles than other Icius spiders.[5]

Icius minimus is endemic to Ethiopia.[1] The holotype was discovered in 1982 in the Awash National Park near hot springs. Other examples have been found in clumps of Cyperus papyrus and other vegetation close to lakes.[5]