| | The spider families of Britain and Ireland |
~Thomisidae
Running Crab Spiders.
Morphology. The adult spiders 4–7 mm long; of medium build to decidedly plump-bodied (mostly), or slender-bodied (e.g., conspicuously so in male Tibellus); decidedly short-legged, or with legs of medium length; not crab-like in stance and locomotion (at least, less obviously so than in the related Thomisidae); with eight eyes (black and beady). The eyes in two horizontal rows of 4; all dark; not ringed with white hairs. The palpal organs of the male of complex structure and enclosed by the specialized, hollowed tarsal segment (the cymbium). The first two pairs of legs forwardly directed, laterigrade; conspicuously longer and often stouter than the third and fourth pairs (but the stance and locomotion less obviously crab-like than in Thomisidae), or not markedly longer and stouter than the third and fourth pairs. Metatarsus IV of the females without a calamistrum. Tarsal claws 2. The tarsi with claw tufts. The abdomen conspicuously patterned dorsally. The abdomen of the females without a cribellum.
The adults not making snare-webs; actively pursuing their prey (active on foliage and ground vegetation, sometimes in buildings, and capable of rapid movement).
Representation in Britain and Ireland. 15 species in Britain; in the genera Philodromus, Thanatus, and Tibellus.
Comments. The form, posture and locomotion of these active hunters are less obviously crab-like than in the sedentary Thomisidae s. str., of which this family is a recent segregate.
Illustrations. • Philodromus dispar, Philodromus histrio. 55, Philodromus dispar Walck.: a, female; b, male; c, palpal organs of the male. 57, Philodromus histrio (Latr.), female. From Blackwall (1861). • Philodromus cespitum. Philodromus cespitum (Walck.). 58a and 59, female; 58b, male; c, eyes; d, maxillae and labium; e, caphalothorax and abdomen, from the side; f, claw and scopula; g, palpal organs of the male. Blackwall labelled his Fig 58 P. cespiticolis, this apparently referring to P. aureolus cespiticollis, which is now known as P. cespitum (Walck.). From Blackwall (1861). • Philodromus margaritatus, Tibellus sp.. 56, Philodromus margaritatus (Clerck). 60, Tibellus sp. (either T. oblongus (Walck.) or T. maritimus Menge, which are not distinguishable from Blackwall's representation): a, female; b, immature male. From Blackwall (1861).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. The spider families of Britain and Ireland. Version: 5th August 2019. delta-intkey.com’.
