Stenaelurillus senegalensis

Stenaelurillus senegalensis is a species of jumping spider in the genus Stenaelurillus that lives in Senegal. Named after the country where it was first found, it was first described in 2018 by Dmitri Logunov and Galina Azarkina. The spider is small, with a carapace between 1.7 and 2.5 mm long and abdomen between 1.6 and 3.45 mm long, although the female is larger than the male. The carapace is hairy, brown and has two white stripes. The abdomen differs between the male and female. The male has a pattern of yellow spots and a brown stripe. The female has a cross of yellow stripe and two brown stripes. The male has a bulging palpal bulb while the female has a flat epigyne with widely separated and backward-facing copulatory openings. It is similar to Stenaelurillus nigricaudus, also found in the country, but can be distinguished by the design of its long straight embolus and the lack of pockets in the epigyne.

Taxonomy
Stenaelurillus senegalensis was first described by Dmitri Logunov and Galina Azarkina in 2018. It was placed in the genus Stenaelurillus, first raised by Eugène Simon in 1886. The genus name relates to the genus name Aelurillus, which itself derives from the Greek word for cat, with the addition of a Greek stem meaning narrow. It was placed in the subtribe Aelurillina in the tribe Aelurillini by Wayne Maddison in 2015, who listed the tribe in the clade Saltafresia. Two years later, in 2017, it was grouped with nine other genera of jumping spiders under the name Aelurillines. The species is named after Senegal, the country in which it was first found.

Description
The spider is medium-sized. The male has a brown carapace that measures between 1.7 and 2.1 mm in length and between 1.4 and 1.6 mm in width. It is covered in brown scales and has wide stripes made of white scales, along with edging also of white scales. The abdomen is yellow and brown, between 1.6 and 2.0 mm long and 1.3 and 1.45 mm wide. The abdomen has a pattern consisting of four yellow spots and a wide hairy brown stripe. The eye field is brown and is decorated with both yellow-white scales and long brown bristles. The chelicerae, clypeus and pedipalps are yellow with white hairs. The front spinnerets are yellow but the back ones are brown; the legs are also brown. The palpal bulb is shaped like a bulge and has distinctive appendages. The embolus is long and straight.

The female is similar to the male in shape but slightly larger. It has a carapace 2.5 mm long and 2.0 mm wide and an abdomen that has a length of 3.45 in and width of 2.65 mm. The colouring on the carapace is similar to the male. The abdomen is more grey in colour and has a pattern consisting of two parallel brown stripes crossed by a yellow stripe, all made of hairs, and a fringe of white hairs. The spinnerets and legs are all yellow. The epigyne is flat and lacks the pocket that is the feature of many of the genus. The copulatory openings are widely separated and face backwards. It has short and wide insemination ducts and large round spermathecae.

The spider is very similar to Stenaelurillus nigricaudus, especially in the colour and patterns on the spider's body. However, it can be distinguished by the design of the sexual organs. Stenaelurillus senegalensis has a long straight embolus and lacks the pocket in the epigyne of the other species.

Distribution
The species is endemic to Senegal. The holotype was identified based on a specimen collected near Richard Toll in 1991. It is known only from that local area. There is some overlap with the range of the more widely distributed Stenaelurillus nigricaudus, which is also found in the same country but has also been found in other areas of Africa. It has been found in areas of savanna.