Nigorella aethiopica

Nigorella aethiopica is the type species of the genus Nigorella. A jumping spider that lives in Ethiopia and named in honour of the country in which it is found, it was first described in 2008 by Wanda Wesołowska and Beata Tomasiewicz. The spider is larger than others in the species with a cephalothorax that is between 4.1 and 4.8 mm long and an abdomen that is between 4.3 and 5.6 mm long. The carapace is generally brown and hairy, although the male is darker. While the male abdomen is marked by a light stripe on the topside and dots underneath, the female abdomen has a pattern of a light stripe and patches on the top and dark stripes on the bottom. As well as the larger size, there is a split at the end of the appendage on the pedipalp tibia that marks out the male, and the female has longer seminal ducts and thinner spermathecae than others in the genus.

Taxonomy
Nigorella aethiopica is a jumping spider species first described by Wanda Wesołowska and Beata Tomasiewicz in 2008. It is one of over 500 species identified by Wesołowska. The genus Nigorella was raised by Wesołowska and Tomasiewicz at the same time. They described the genus name as an arbitrary arrangement of letters. Medium-sized to large, the spiders resemble Hyllus, but differ in the design of the copulatory organs of both sexes. In 2015, Wayne Maddison listed the genus in the subtribe Plexippina in the tribe Plexippini. Previously termed Plexippeae, by Eugène Simon in 1901, and identified as a subfamily, the tribe is part of the clade Saltafresia. In 2017, the genus was grouped with seven other genera of jumping spiders under the name Evarchines, named after the genus Evarcha, by Jerzy Prószyński. Nigorella aethiopica was designated the type species for the genus. The species is named after Ethiopia, the country where it was first found.

Description
Nigorella aethiopica is large spider, the largest in the genus, with a total length of about 10 mm. The male has a cephalothorax that is typically between 4.1 and 4.8 mm long and 2.8 and 3.5 mm wide. The carapace is oval, medium height, dark coloured and covered in short brown hairs. The eye field is short and black with long bristles near to eyes themselves. The abdomen is similar in size, between 4.3 and 5 mm long and between 2.3 and 3 mm wide. It is a dark brown oval that is also covered in dark brown hairs. There is a light stripe down the middle of the topside and four rows of dots on the underside. The chelicerae are bulky, very dark and unidentate. The clypeus is low and dark. The spinnerets are dark and the legs are dark brown with long brown hairs. The pedipalps are dark, apart from the tip of the rounded tegulum. The palpal bulb is also rounded. The tibia has a wide appendage, or apophysis, that has a notch on the end and surrounds the embolus.

The female is similar in shape to the male but lighter in colour and less hairy. It has a cephalothorax that is typically 4.7 mm in length and 3.4 mm in width and an abdomen that measures typically 5.6 mm in length and between 3.4 mm in width. The carapace is lighter brown with a lighter stripe, and there are traces of two streaks on the eye field. There is a pattern consisting of a light stripe towards the front of the top of the abdomen and eight patches in pairs to the back. The underside has three dark stripes across the lighter middle, with darker areas towards the edges. The legs are also lighter, with lighter hairs. In comparison, the chelicerae are similar to the male. The clypeus have small white hairs and the pedipalps are more yellow. The epigyne is short, wide and marked by two widely-separated and heavily sclerotised openings and two pockets. The species shares the sclerotised cup-like areas which hide the gonopores in the epigyne that helps to distinguish Nigorella spiders.

As well as its larger size, the species can be differentiated from others in the genus by its copulatory organs. The split in the tip of the tibial apophysis helps distinguish the male while the female can be identified by its longer seminal ducts and slimmer spermathecae. The species is very similar in appearance to the smaller Nigorella plebeja and can be confused with it. However, this species has a single tip to the tibial apophysis.

Distribution
Nigorella aethiopica is endemic to Ethiopia. The holotype was discovered in 1986 in the Awash National Park. Its species distribution is the furthest east of any spider in the genus.