northern long-toothed sheetweaver

not listed

NNR - Unranked

not listed

Northern long-toothed sheetweaver is a small sheetweb spider. It occurs in North America from Maine south to North Carolina and west to Minnesota, in Colorado, New Mexico, Montana, and Washington, and across southern Canada. It is common in Minnesota but often overlooked due to its small size and cryptic coloration. Adults are found almost exclusively on the bark of a tree, where its color and markings provide excellent camouflage. Spiderlings mature in leaf litter on the ground.

Females are ⅛″ to 3⁄16″ (4.0 to 4.5 mm) in length. Males are smaller, ⅛″ (3.2 to 3.8 mm) in length.

The front part of the body (cephalothorax) is egg-shaped when viewed from above and flat when viewed from the side. There are eight eyes arranged in two parallel rows of four eyes each. All of the eyes are on black spots. The anterior median eyes (AME) are smaller than the posterior median eyes (PME). The jaw-like mouthparts (chelicerae) have five or six strong teeth on the forward-facing margin and four or five teeth on the rearward facing margin. On the female, the spines on the finger-like sensory mouthparts (palps) are long and conspicuous. The median ocular area (MOA), the area defined by the middle four eyes, is narrower in front than behind. The top of the cephalothorax (carapace) is light with dark brown or black markings, including a Y-shaped mark in the middle, a thin line on the margins, three spots on each side between the middle mark and the margin, and a short stripe behind each posterior lateral eye (PLE).

The abdomen is broadly oval, highest in front, and pointed at the rear. It is light with several pairs of gray or black spots.

The legs are long, thin, and spiny. They are light with dark rings. There are three minute claws at the end of the last segment (tarsus) but these are not visible without magnification.

Female Body Length: ⅛″ to 3⁄16″ (4.0 to 4.5 mm)

Male Body Length: ⅛″ (3.2 to 3.8 mm)

The web is a flat sheet pressed closely against the tree trunk, making it difficult to see. There is no retreat.

Woodlands

July through September

Adults are sedentary hunters.

Spiderlings disperse in the fall by “ballooning”. They climb a branch, blade of grass, or fencepost, and release a long thread of silk. The silk thread catches the wind or even a light breeze and the spiderling floats to a new site.

Small insects and smaller spiders.

Sources

24, 29, 30, 82.

Common

Some authors place sheetweb spiders in the subfamily Linyphiinae, while others place it in the subfamily Micronetinae.

Location: Albany, NY

Location: Woodbury, MN