Thiratoscirtus mastigophorus

Thiratoscirtus mastigophorus is a small spider with distinctive physical features. The spider's body is divided into two main parts: an ovoid forward section or cephalothorax and, to the rear of that, an oval abdomen. Males of this species have a cephalothorax measuring typically 1.9 mm (0.07 in) in length and 1.5 mm (0.06 in) in width. The carapace, the hard upper part of the cephalothorax, is high with a slight slope down the back. It is generally brown with a v-shaped marking on the top. The spider's eye field is dark brown with a black area around the eyes themselves. Small fawn scales encircle some of the eyes. White hairs form thin streaks on the edges of the carapace and the underside of the cephalothorax, or sternum, is light brown. The spider's face, known as the clypeus, is low.^[13]

The spider has stout chelicerae that are short and brown. Its other mouthparts are similar in colour, tending to dark brown to yellowish fringes to the maxillae. The male's abdomen is an elongated ovoid that measures typically 1.7 mm (0.07 in) in length and 1.2 mm (0.05 in) in width. The upperside is mainly brownish with a light band running down its middle that breaks up into chevrons towards the back. There are two stripes along the sides while the underside is greyish-brown. The spider's spinnerets are yellowish with some parts darker than others. Its legs are brownish with yellowish patches visible on some examples. The front pair of legs are darker, longer, stouter, and armed with noticeable spines. Its pedipalps, sensory organs near the mouth, are yellow.^[13]

The female is generally similar to the male. Its carapace is slightly shorter, being 1.8 mm (0.07 in) long and 1.5 mm (0.06 in) wide, and darker. The eye field is more uniform and darker with streaks of white hair to the back. The abdomen is larger than the male, typically measuring 2.2 mm (0.09 in) in length and 1.7 mm (0.07 in) in width. It also has a distinctively different design. The top is covered in a mosaic of small brown and yellowish patches, which make an uneven pattern, and a series of chevrons to the rear.^[14]

The spider is best distinguished from related species by its copulatory organs. The male's long whip-like embolus, referenced in the specific name, is a clear determining feature. It sprouts from the bottom of the spider's palpal bulb, circles around the bottom and sides to curve and follow the line of the cymbium nearly to its end. Its palpal bulb is small and round with a pronounced lobe sticking out of its side. Its cymbium is narrow and has small hairs at its top. It has a relatively small palpal tibia that has a slightly curved protrusion, or tibial apophysis.^[15]

The female has a long epigyne with a noticeable depression in the middle to the front. Behind this, there is a structure than shows significant sclerotization, as does the v-shaped edge at the very back of the epigyne. Two copulatory openings can be found at the back of the depression, which lead to short thick insemination ducts and large spherical spermathecae, or receptacles.^[16] Compared to other species, the central depression of the epigyne, although similar to Thiratoscirtus bipaniculus and Thiratoscirtus kalisia, is distinctive. Thiratoscirtus mastigophorus also has shorter, wider insemination ducts.^[2][17]

Thiratoscirtus spiders generally live in Africa and are particularly common in the forests of Central and West Africa.^[5] Thiratoscirtus mastigophorus is endemic to the Democratic Republic of Congo. The male holotype was found near Butembo in 1975 in suspended soil. Other specimens have been found nearby. Female paratypes have also been seen in other parts of Kivu. It inhabits forest environments, where it is associated with epiphytic plants, at altitudes of between 1,700 and 1,750 m (5,580 and 5,740 ft) above sea level.^[2] The species lives amongst epiphytic plants.^[18]