Neaetha wesolowskae

Neaetha wesolowskae is a small spider with a body divided into two main parts: a broad cephalothorax and an oval abdomen. The male has a rather high carapace, the hard upper part of the cephalothorax, that is 1.49 mm (0.059 in) long and 1.3 mm (0.051 in) wide. It is robust, and with a distinctive sloping thorax. The carapace is brown and covered in white scales with a distinct fovea, or depression, in its middle. There are more scales on the sides but none on the sternum, the underside of the cephalothorax, which is light brown. The spider has a darker eye field. The spider's face, or clypeus, is brown with light scales on the bottom. The chelicerae are brown, with two forward teeth and one rear tooth. The rest of the mouthparts, including the labium, are also brown, but have light tips.^[10]

The abdomen is 1.2 mm (0.047 in) long and 0.71 mm (0.028 in) wide and has a pattern of three wide brown stripes on the top. It is covered in brown and whitish scales and hairs, the hairs being longer at the front. The underside of the abdomen is light grey with a pattern of darker spots. The spinnerets are light brown and the legs are brown. The first pair of legs are wider than the others. The pedipalps are hairy. The palpal tibia has a long narrowing projection, or tibial apophysis, that has a pointed and slightly bent tip. The palpal bulb has an ovoid tegulum with a straight sperm duct and a crescent-shaped embolus. The shape of the embolus differentiates the species from the related Neaetha absheronica, Neaetha membrosa and Neaetha tomkovichi.^[10]

The female has a similar carapace, although smaller at 0.86 mm (0.034 in) long and 0.74 mm (0.029 in) wide. The carapace is brown and has black areas near the eyes like the male but is covered in brown as well as white scales. White scales can also be found on the brown clypeus, which has longer bristles as well. The sternum and chelicerae are light brown and brown respectively like the male but the labium is darker. The legs are slightly lighter than the male. The abdomen is more clearly different, as it is both smaller, measuring 0.97 mm (0.038 in) in length and between 0.72 mm (0.028 in) in width, and has a pattern of darker spots on a yellow background. The spinnerets also differ, being light brown.^[11]

The females of the genus are generally hard to distinguish.^[12] However, the copulatory organs on Neaetha wesolowskae are distinctive. The epigyne is large with a characteristic central pocket. This species has distinctive ovoid, rather than crescent-shaped, copulatory openings that lead to very short copulatory ducts. The spermathecae, or receptacles, are as long as they are wide and sclerotized.^[11] The spider is particular similar to Neaetha tomkovichi, differing in the having a larger pocket on the epigyne and the way that the spermathecae are separated rather than together.^[3]

The species is endemic to Thailand.^[1] The male holotype of the species was found in the Kanchanaburi province in 1979. The female paratype was found in Chonburi province during the same year. This is the most easterly that the genus has been observed. The species lives in rainforests.^[4]