| | The spider families of Britain and Ireland |
Including Dolomedididae
Nursery-web Spiders, Raft Spiders.
Moving across the surface of still water to take victims from it (Dolomedes), or terrestrial.
Morphology. The adult spiders 9–22 mm long; slender-bodied, or of medium build; decidedly short-legged, or with legs of medium length (less than twice the body length); with eight eyes. The eyes ostensibly in three rows of 4+2+2, the anterior row of four more or less recurved (comprising a recurved front row of four small, equal-sized members, and two pairs of larger, equal-zized eyes forming a trapezium behind). The palpal organs of the male of complex structure and enclosed by the specialized, hollowed tarsal segment (the cymbium). The trochanters of all the legs notched. Metatarsus IV of the females without a calamistrum. Tarsal claws 3. Tarsus IV without a ventral ‘comb’. The abdomen conspicuously patterned dorsally. The abdomen of the females without a cribellum. The reproductive openings of the females associated with an epigyne.
The adults not making snare-webs (but the females construct nursery webs for the protection of their young); actively pursuing their prey (ground running, and in the case of Dolomedes moving over still water to take prey, the movements of which are detected by a submerged leg as the spider lies in wait at the water’s edge. Dolomedes sometimes takes small fish, as well as invertebrates). The females carrying egg sacs via their chelicerae and palps.
Representation in Britain and Ireland. 3 species in Britain; in the genera Dolomedes and Pisaura.
Illustrations. • Dolomedes fimbriatus and Pisaura mirabilis. 18, Pisaura mirabilis (Clerck): a, female; b, male; c, eyes; d, mouthparts, sternum and palpus of the female; e, outline of the cephalothorax and abdomen, from above; f, palpal organs of the male, from below; g; the latter in profile. 19, Dolomedes fimbriatus (Clerck), juvenile female. 20, Dolomedes fimbriatus (Clerck), mature female. From Blackwall (1861, with approximate lengths of females added).
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’.
