thin-spined jumping spider

not listed

NNR - Unranked

SNR - Unranked

not listed

Thin-spined jumping spider is a relatively small jumping spider. It occurs in the United States east of the Rocky Mountains and in adjacent Canadian provinces. Adults are found all summer on bushes and tall grasses, and under stones and boards.

The male is ⅛″ to 3 ⁄16″ (4.5 to 5 mm) long not including the legs. The entire body is densely covered with greenish iridescent scales and a few white hairs. The scales are iridescent and may appear light or dark depending on the angle of the light. The front part of the body (cephalothorax) is larger than the abdomen. The plate covering the cephalothorax (carapace) is reddish-brown, about two thirds as long as wide, and is slightly overlapped by the abdomen so that the body does not appear ant-like. When viewed from above the sides of the carapace are nearly parallel. When viewed from the side it is of moderate hight, more than half as tall as wide at its widest point, but only moderately convex.

There are four pairs of eyes arranged in what appears to be three rows occupying less than half of the carapace. The first row of four eyes, consisting of the anterior median eyes (AME) and anterior lateral eyes (ALE), is curved backward. The AME is the middle and forward-most pair of these. They are by far the largest of all of the eyes and can be moved. The AME are about twice as large as the ALE. The second row of two eyes are the posterior median eyes (PME). They are very small and are barely or not at all noticeable on most photos. The third row of eyes is the posterior lateral eyes (PLE). The PLE is set far back on the head and is only slightly wider than the first row of four eyes (AME and ALE together). The PME and ALE form a wide rectangle. The AME is closer to the ALE than to the PLE. The PME is closer to the ALE than to the PLE. There is a tuft of mostly brown and a few white hairs above each AME.

The legs are short, longitudinally striped, oriented forward, and adapted for jumping. The front legs are the longest and are only slightly enlarged. The fourth leg segment (patella) is about twice as long as the fifth segment (tibia). The patella and tibia on the front legs have a long white fringe on the underside. The tibia on the front legs have two pairs of spines and on the underside a tuft of black hairs. There are two pairs of spines on the tibia of the second pair of legs, and two pairs on the sixth segment (metatarsus) of all legs except the second pair, which has only a single pair of spines. All of the spines are fine and are difficult to see.

The female is larger, 3 ⁄16″ to ¼″ (5 to 6 mm) with a legspan of ¼″ to ⅜″ (6 to 9 mm). The carapace is darker but the color is otherwise similar to the male. The abdomen is larger than the carapace and there is a white band around the base. The legs are more distinctly longitudinally striped. There is no tuft of hairs above each AME.

Female Body Length: 3 ⁄16″ to ¼″ (5 to 6 mm)

Male Body Length: ⅛″ to 3 ⁄16″ (4.5 to 5 mm)

Legspan: ¼″ to ⅜″ (6 to 9 mm)

No web

Bushes and tall grasses, under stones and boards

All summer

Sources

Location: Woodbury, Minnesota