northern long-toothed sheetweaver

(Drapetisca alteranda)

Conservation Status
northern long-toothed sheetweaver
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

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 to 316 (4.0 to 4.5 mm) in length. Males are smaller, (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 (AMEs) are smaller than the posterior median eyes (PMEs). 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.

 
     
 

Size

 
 

Female Body Length: to 316 (4.0 to 4.5 mm)

Male Body Length: (3.2 to 3.8 mm)

 
     
 

Web

 
 

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

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Woodlands

 
     
 
Biology
 
 

Season

 
 

July through September

 
     
 

Behavior

 
 

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.

 
     
 

Life Cycle

 
 

 

 
     
 

Food

 
 

Small insects and smaller spiders.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 29, 30, 82.

 
  5/21/2022      
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
  Class Arachnida (arachnids)  
 

Order

Araneae (spiders)  
 

Suborder

Araneomorphae (typical spiders)  
 

Infraorder

Entelegynae (entelegyne spiders)  
 

Superfamily

Araneoidea  
 

Family

Linyphiidae (sheetweb and dwarf spiders)  
 

Subfamily

Linyphiinae (sheetweb spiders)  
 

Genus

Drapetisca  
       
 

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

 
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

northern long-toothed sheetweaver

 

 

 

 

 

 

 

Glossary

Carapace

The hard, upper (dorsal), shell-like covering (exoskeleton) of the body or at least the thorax of many arthropods and of turtles and tortoises. On crustaceans, it covers the cephalothorax. On spiders, the top of the cephalothorax made from a series of fused sclerites.

 

Cephalothorax

The front part of the body of various arthropods, composed of the head region and the thoracic area fused together. Eyes, legs, and antennae are attached to this part.

 

Chelicerae

The pair of stout mouthparts, corresponding to jaws, in arachnids and other arthropods in the subphylum Chelicerata.

 

Palp

Short for pedipalp. A segmented, finger-like process of an arthropod; one is attached to each maxilla and two are attached to the labium. They function as sense organs in spiders and insects, and as weapons in scorpions. Plural: palpi or palps.

 

Tarsus

On insects, the last two to five subdivisions of the leg, attached to the tibia; the foot. On spiders, the last segment of the leg. Plural: tarsi.

 

 

 

 

 

 

 
 
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Alfredo Colon

 
    northern long-toothed sheetweaver      
           
 
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Other Videos
 
  Ecology, Diversity, & Life History 16: Michael Draney
American Arachnological Society
 
   
 
About

Jul 3, 2021

Spatial Distribution of a Tree Trunk Specialist Spider (Linyphiidae: Drapetisca alteranda): Landscape Versus Microhabitat Drivers

 

 

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  Alfredo Colon
8/21/2019

Location: Woodbury, MN

northern long-toothed sheetweaver  
           
 
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Created: 5/21/2022

Last Updated:

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