punctated ground crab spider

(Xysticus punctatus)

Conservation Status
punctated ground crab spider
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Punctated ground crab spider is a small crab spider. It occurs in the northern United States and across southern Canada. It is uncommon in Minnesota. It is found from May through August on tree foliage forests and woodlands.

Adults are hard-bodied and bristly. The female is 316 to (5.4 to 8.7 mm) in length and has a legspan of ½ to 1116 (12 to 18 mm). The male is much smaller, to 316 (3.5 to 5.0 mm) in length.

The plate (carapace) covering the front part of the body (cephalothorax) is moderately high, slightly longer than wide, and smoothly rounded on the sides when viewed from above. When viewed from the side it is slightly convex, highest near the front, and it drops down toward the back near the base of the third pair of legs. The sides of the carapace are dark brown. There is a broad pale stripe in the middle that narrows toward the rear, and there is a narrow pale line on each lateral margin. The area around the eyes is pale. The rear of the carapace is overhung by the abdomen.

There are eight eyes arranged in two curved rows of four. The front (anterior) row is curved forward and the rear (posterior) row is curved backward. The lateral eyes are larger than the median eyes and are on low raised projections (tubercles). The anterior median eyes (AMEs) are closer to the anterior lateral eyes (ALEs) than to each other. The posterior median eyes (PMEs) are closer to each other than to the posterior lateral eyes (PLEs). The median ocular area (MOA), the area defined by the middle four eyes is broader than long and slightly narrowed in front. The plate on the face above the mouth (clypeus) is armed with several long spines. The jaws (chelicerae) are small and have no teeth.

The abdomen is large, broadly oval, widest toward the rear, and flattened above. It is mostly brown with a broad, sharply irregular stripe in the middle. It is pale around the outside edges and there are also short black bands on the rear half.

The legs are stout and fairly long. The first and second pairs of legs are long, strong, spiny, and nearly equal in length. They are normally held out and forward, like a crab. This is the feature that gives the family Thomisidae its common name. The third and fourth pairs are shorter and nearly equal in length. On the first pair, the third segment (femur) is slender and about four times longer than wide, and the fifth segment (tibia) has 3 or 4 pairs of stiff hairs on the upper side. The last leg segment (tarsus) on each leg has two claws at the end but these are not visible without magnification. The tarsi on all legs do not have a brush of hairs (scopula) on the underside, and there is no tuft of hairs (claw tuft) at the end on any leg.

 
     
 

Size

 
 

Female Body Length: 316 to (5.4 to 8.7 mm)

Male Body Length: to 316 (3.5 to 5.0 mm)

Legspan: ½ to 1116 (12 to 18 mm)

 
     
 

Web

 
 

Crab spiders do not make webs.

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Forests and woodlands

 
     
 
Biology
 
 

Season

 
 

May through August

 
     
 

Behavior

 
 

When the legs are held out to the side the spider is able to walk forward, backward, or sideways (laterigrade).

The female does not build webs, snares, or retreats. To protect its egg sac it will fold over the edge of a leaf and secure it with silk.

 
     
 

Life Cycle

 
 

 

 
     
 

Food

 
 

Insects and other spiders

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 29, 30, 82.

 
  4/16/2022      
         
 

Occurrence

 
 

Uncommon in Minnesota

 
         
 
Taxonomy
 
  Class Arachnida (arachnids)  
 

Order

Araneae (spiders)  
 

Suborder

Araneomorphae (true spiders)  
 

Superfamily

Thomisoidea (crab and running crab spiders)  
 

Family

Thomisidae (crab spiders)  
 

Genus

Xysticus (ground crab spiders)  
       
 

Synonyms

 
 

Misumenops punctatus

 
       
 

Common Names

 
 

punctated ground crab spider

 

 

 

 

 

 

 

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.

 

Clypeus

On insects, a hardened plate on the face above the upper lip (labrum).

 

Femur

On insects and arachnids, the third, largest, most robust segment of the leg, coming immediately before the tibia. On humans, the thigh bone.

 

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.

 

Tibia

The fourth segment of an insect leg, after the femur and before the tarsus (foot). The fifth segment of a spider leg or palp.

 

Tubercle

On plants and animals: a small, rounded, raised projection on the surface. On insects and spiders: a low, small, usually rounded, knob-like projection. On slugs: raised areas of skin between grooves covering the body.

 

 

 

 
 
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Alfredo Colon

 
    punctated ground crab spider   punctated ground crab spider  
           
 
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ysticus punctatus
Andree Reno Sanborn
  Xysticus punctatus  

 

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  Alfredo Colon
8/2/2019

Location: Woodbury, MN

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Created: 4/16/2022

Last Updated:

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