Langelurillus primus

Langelurillus primus is a small spider. The male has an orange-brown carapace that is typically 2.2 mm (0.087 in) long and 1.65 mm (0.065 in) wide and has an orange pattern on its thorax. The eye field is brownish-black. The clypeus is yellowish-orange and slightly narrower than the diameter of some of the eyes. The chelicerae is yellowish-orange and toothless. The labium and sternum are also yellowish-orange. The yellowish-green abdomen is typically 1.95 mm (0.077 in) long has a pattern of greyish spots its back and rectangular scutum. It has black stripes on its spinnerets. The legs have brown hairs and spines.^[2] The pedipalp is hairy and has a large ovoid tegulum.^[6] It has three tibial apophyses, or spikes, and a prolateral tibial process that is shaped like a triangle.^[7] The embolus is short and pointed.^[8]

The female is slightly longer than the male. It has an orange-brown or dark brown pear-shaped carapace that is between 2.35 and 2.8 mm (0.093 and 0.110 in) long and 1.6 and 1.9 mm (0.063 and 0.075 in) wide and has a stripe down the middle made of white hairs. The clypeus is similar but covered in white hairs. The chelicerae are orange-brown or light brown with one small tooth towards the back in some examples. It has a less orange in its yellow labium and sternum, while the legs are short and orange-yellow or dark yellow and covered with dense brown hairs. The abdomen is greyish-brown or yellowish with brown spots and measures between 3.0 and 3.5 mm (0.12 and 0.14 in) long and typically 2.8 mm (0.11 in) wide. The underside is light. The epigyne is very small and has a single pocket and long tube-like seminal ducts that lead to multi-chambered and highly sclerotised oval spermathecae.^[2][9]

The spider is similar to others in the genus. The female can be distinguished from Langelurillus kenyaensis by its shorter and less looped seminal ducts.^[9] The related Langelurillus krugeri can be identified by its shorter seminal ducts and the way that the spermathecae are placed perpendicular, rather than parallel, to the epigastric furrow.^[10]

Almost all, if not all, Langelurillus spiders live in sub-Saharan Africa.^[11] Langelurillus primus is endemic to Kenya.^[1] The holotype was discovered in 1975 in Meru National Park.^[2] It was also found near Lake Bogoria in 1971 and has only been identified in those areas of the country.^[9][12]