Bassaniana utahensis

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Current valid name

Bassaniana utahensis (Gertsch) (family Thomisidae)

Recognition and diagnostic features

Crab-like in appearance with front two pairs of legs much longer than hind two pair, carapace flattened in lateral view for entire length.

Related or similar species

Xysticus locuples, Xysticus californicus


Body lengths when mature: male: 4.6 - 6.0 mm, female: 6.3 - 8.0 mm

Immatures resemble miniature adults.

Egg sac

No egg or egg sac information is available for this species


In California: much of the state

Elsewhere: throughout North America

Native to North America

This species has not been transported or become established outside of its range.


Found under bark, stones, natural debris like leaf-litter; will rarely be found in grape clusters. Males collected May through October, females collected year-round.

Status in table grapes

Level of Incidence: uncommon

Level of Concern in New Zealand: WPNZ (May 2010) nr, BORIC (Dec 2011) nr (not listed), MAF-BPRA (2002) nr (coding definition)

Level of Concern in Australia: WPAU (2006) nr (coding definition)

Level of Medical importance: none

Common name

None for species, crab spiders for family

Taxonomic history

Recently transferred to Bassaniana from Coriarachne, by which it was known for many decades.

Commonly encountered synonyms

Coriarachne utahensis

Selected references

Dondale, C. D., and J. H. Redner. 1978. The insects and arachnids of Canada, part 5: The crab spiders of Canada and Alaska (Araneae: Philodromidae and Thomisidae). Agriculture Canada, Ottawa.

Schick, R. X. 1965. The crab spiders of California (Araneida, Thomisidae). Bull. Am. Mus. Nat. Hist. 129: 1-180.