Aelurillus brutus

Aelurillus brutus is a species of jumping spider in the genus Aelurillus that lives in Kazakhstan and Turkmenistan. The female was first described by Wanda Wesołowska in 1996 and the male by Galina Azarkina in 2003. The spider is small with a carapace that is between 2.5 and 3.2 mm long and an abdomen between 2.4 and 4.7 mm in length. The female is larger than the male. The spider is generally dark brown and hairy, but the male abdomen has a pattern of grey-yellow wavy lines. The difference between this species and others in the genus are subtle. The females are particularly difficult to distinguish. However, there are three distinctive stripes on the eye field and a pattern on the bottom of the abdomen.

Taxonomy
Aelurillus brutus is a jumping spider species first described by Wanda Wesołowska in 1996. It was one of over 500 species identified by the Polish arachnologist during her career. She placed it in the genus Aelurillus that was first circumscribed by Eugène Simon in 1885. The genus name derives from the Greek word for cat. It was placed in the subtribe Aelurillina in the tribe Aelurillini, both named after the genus, by Wayne Maddison in 2015. These were allocated to the clade Saltafresia. In 2017, the genus was grouped with nine other genera of jumping spiders under the name Aelurillines.

Initially, only the female was described. In 2003, Galina Azarkina first described the male, and also demonstrated the relationship between the species and other Aelurillus spiders. She also found that an example of Aelurillus v-insignitus from 1985 had been misidentified and was in fact an example of this species.

Description
The spider is medium-sized. The female has a dark brown, nearly black carapace that is 3.2 mm in length and 2 mm in width. It has a covering of short white hairs and long brown bristles around the eyes, that sit within a short eye field. The carapace is high and looks stretched in length, with more width towards the back. The clypeus, or face of the spider, is dark brown. The chelicerae, part of the mouthparts, are brown. The abdomen is grey-yellow and also looks stretched, measuring 4.7 mm in length and 3.2 mm in width. The back is pointy and the whole abdomen has a scattering of grey-yellow hairs interspersed with brown bristles. The spinnerets are grey-yellow. The legs are hairy and orange-yellow with patches of brown visible. The pedipalps are yellow. The epigyne is oval with a large pocket and two central copulatory openings. The spider has three distinctive stripes on its eye field and, unlike many in the genus, lacks hairs on its legs and the sides of the carapace.

The male is slightly smaller than the female. The dark brown carapace is 2.5 mm long and 1.8 mm wide and covered in white scales. The clypeus is also dark brown like the female. The abdomen is 2.4 mm long and 1.8 mm wide, grey-yellow with a pattern of indistinct wavy lines. The chelicerae, legs and spinnerets are brown-yellow but the pedipalps are brown rather than yellow. The palpal bulb is large with a small embolus.

The species is closely related to Aelurillus helvanacius but the female has distinctive flaps on the epigyne. The morphological differences between the species, Aelurillus ater and Aelurillus dubatolovi are subtle. Unlike Aelurillus ater, the spider has white hairs on the clypeus and, unlike both the other species, short hairs on the side of the carapace and a pattern on the bottom of the abdomen. Not unusually for this genus, the females of all three species are hard to tell apart.

Distribution
The spider was first found in Gaplaňgyr Nature Reserve on the south Ustyurt Plateau in Turkmenistan. The holotype, a female, was collected in 1985. The spider has also been seen in the Repetek Biosphere State Reserve. In 2003, Azarkina extended the species distribution to include Kazakhstan based on paratypes found on the then-island Barsa-Kelmes, in the Ustyurt Nature Reserve and on the Mangyshlak Peninsula. It is reckoned to live across both western Kazakhstan and Turkmenistan.