Maevia Inclemens - Description

Description

Carapace over cephalothorax Abdomen Eyes Legs Palps Chelicerae, housing fangs Main features of a jumping spider

Spiders are chelicerates, which differ from other arthropods in that the usual body segments are fused into only two tagmata, the cephalothorax and abdomen. Spiders' abdomens bear appendages that have been modified into spinnerets that extrude silk from up to six types of silk glands within their abdomen. The cephalothorax and abdomen are joined by a small, cylindrical pedicel, which allows the abdomen to move while spinning silk.:571-574 While most jumping spiders do not build webs to catch prey, they use silk for other purposes, including molting and laying eggs.:495

Jumping spiders have large forelegs and short, powerful back legs. Unlike most arthropods, spiders have no extensor muscles in their limbs and instead extend them by increasing their blood pressure. Jumping spiders can leap several times their own length by powerfully extending the third or fourth pairs of legs,:578 reaching up to 200 millimetres (7.9 in) with the forelimbs extended to grasp the prey. Spiders maintain balance when walking, so that legs 1 and 3 on one side and 2 and 4 on the other side are moving, while the other four legs are on the surface. To run faster, spiders increase their stride frequency.:328

In spiders and other chelicerates, there is only one pair of appendages before the mouth, and in spiders these are modified into fangs that inject poison into the prey. Behind the mouth is a pair of pedipalps ("palps" for short), and those of male spiders are quite large and are used for displaying and mating.

Spiders groom themselves regularly, and more often if wet or dirty. They moisten their fangs, draw the legs one at a time through the fangs, and "comb" the legs with the fangs and palps. The first and fourth pairs of legs are then used to groom other parts of the body, and the only place they appear not to reach is the dorsal surface of the carapace.:53

The body of M. inclemens is only sparsely covered with hairs and scales.:2 A female of Maevia inclemens is 6.5 to 8.0 millimetres (0.26 to 0.31 in) long,:3-4 her carapace is light brown, her legs are pale and unmarked. The top of her abdomen is chalky:3-4 or rusty colored, and along each side is a black band, often thinly covered with orange scales. Sometimes there is series of chevrons (V-shaped markings) along the middle of her abdomen.:3-4 She has a prominent white stripe below the foremost eyes. There are spines on the first and second pair of her legs, but her body never has tufts of hair.:3-4 Males are 4.75 to 6.50 millimetres (0.187 to 0.256 in) long, and their carapaces are light to dark brown, with a black line around the edge. There usually is a pair of large lighter areas between the last pair of eyes halfway down the back of the carapace. The eyes are surrounded by black. :3-4 Males occur in two forms, a very rare phenomenon in zoology. The "tufted" morph has a totally black body, black pedipalps, white legs and three tufts of bristles on the front part of the cephalothorax. The "gray" male morph has a black and white striped body, a prominent white stripe on the foremost eyes, striped legs and bright orange pedipalps, and no tufts.:161-162

Jumping spiders have a distinctive rectangular carapace,:51 and that of female Maevia inclemens average 2.30 millimetres (0.091 in) wide, while the carapaces of males average 2.10 millimetres (0.083 in).:1989 The carapace of M. inclemens is fairly high, between 60% and 70% of the width.:1