| Calculus six-eyed ground spider | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Arachnida |
| Order: | Araneae |
| Infraorder: | Araneomorphae |
| Family: | Orsolobidae |
| Genus: | Calculus Purcell, 1910 [1] |
| Species: | C. bicolor |
| Binomial name | |
| Calculus bicolor Purcell, 1910 [1] | |
Calculus bicolor, the sole species of the genus Calculus, is a South African spider in the family Orsolobidae. [1]
Individuals are 4 mm in length, although only juveniles have been described. The abdomen is pale yellow with a broad brown patch and black markings on the sides of the spinnerets. [2] Calculus bicolor was described in 1910 by William F. Purcell, and long assigned to the Oonopidae (goblin spiders), until a 2012 study assigned Calculus to the family Orsolobidae on the basis of sensory organs that differed from those of oonopids. [3]