Bacelarella gibbosa

Bacelarella gibbosa is a species of jumping spider in the genus Bacelarella that is endemic to Nigeria. The spider has a distinctive shape to the carapace that gives the species its name, which can be translated hunchback. It was first described in 2012 by Wanda Wesołowska and Glavis Edwards. The spider is medium-sized with a cephalothorax that has a length between 3.1 and 3.8 mm and an abdomen that is between 2.6 and 3.4 mm long. The female is larger than the male. It is also generally lighter in colour, the male having a darker brown carapace, clypeus and legs. The species can be distinguished from others in the species by the male's round small palpal bulb and long thin embolus and the larger pocket in the female's epigyne.

Taxonomy
Bacelarella gibbosa was first described by Wanda Wesołowska and Glavis Edwards in 2012. It is one of over 500 species identified by the Polish arachnologist Wesołowska. It was allocated to the genus Bacelarella, which itself had been first raised by Lucien Beland and Jacques Millot in 1941. The genus was named in honour of the Portuguese arachnologist Amélia Vaz Duarte Bacelar. The species name is the Latin word for humpbacked and relates to the shape of the carapace. In 2008, the genus was allocated to a clade named the Bacelarella group based on DNA sequencing. This was then refined into a subtribe of the tribe Aelurillini in the clade Saltafresia.

Description
The spider is medium-sized. The male has a cephalothorax that is 3.1 mm in length and 2.4 mm in width. It has a dark brown oval carapace, although the fovea is slightly lighter, covered in short grey-white hairs. It has a distinctive high shape. The abdomen is also dark and hairy, 2.6 mm long and 1.9 mm wide, but has two large orange patches that are shaped like butterflies. The clypeus is also dark, as are the mouth parts. The chelicerae has three teeth, one larger than the rest. The forward spinnerets are brown and the rear yellow, while the legs are dark brown. The pedipalps are hairy and brown, while the palpal bulb is small and round and has a long thin embolus which distinguishes it from other species in the genus.

As is typical for the genus, the female is larger than the male. The cephalothorax is between 3.3 and 3.8 mm from front to back and between 2.5 and 2.9 mm from side to side while the abdomen measures between 3.2 and 3.4 mm in length and between 2.2 and 2.6 mm in width. The carapace is similar in shape but lighter in colour apart from the area around the eyes, which are also marked with translucent hairs and long brown bristles. The clypeus is also lighter brown and the mouth parts are lighter, although the chelicerae are similar. The spinnerets are all yellow while the legs are brown. The epigyne has a pocket with a furrow and two large oval depressions. The copulatory ducts and spermatheca and slightly sclerotized. The larger size of the pocket differentiates the species from the similar Bacelarella pavida.

Distribution and habitat
The species is endemic to Nigeria. The holotype for the species was found in Cross River State in 1980. It has also been found in other areas in the state, generally in vegetation, both plantations and rainforest. The genus prefers darker areas away from sunlight, except at times of courtship when vision plays an important role.