| | The spider families of Britain and Ireland |
Excluding Metidae
Long-jawed Orb Weavers.
Morphology. The adult spiders 2.5–11 mm long; of medium build, or decidedly plump-bodied; diverse in form, decidedly short-legged, or with legs of medium length, or decidedly long-legged; with eight eyes. The eyes in two horizontal rows of 4; all clear and glassy. The maxillae longer than broad. The palpal organs of the male of complex structure and enclosed by the specialized, hollowed tarsal segment (the cymbium). The male palps with a well developed paracymbium. Metatarsus IV of the females without a calamistrum. Tarsal claws 3. Tarsus IV without a ventral ‘comb’. The abdomen conspicuously patterned dorsally (sometimes green). The epigastric furrow pro-curved between the lung slits. The abdomen of the females without a cribellum. The reproductive openings of the females associated with an epigyne (but very simple in form).
The adults making snare-webs, or not making snare-webs (Pachygnatha); when web-forming, constructing orb webs (with an open hub, often in damp marsh vegetation, strung horizontally or at an angle); in Pachygnatha, actively pursuing their prey (ground running).
Representation in Britain and Ireland. 9 species in Britain; in the genera Pachygnatha and Tetragnatha.
Comments. The posterior margin of the chelicerae exhibits one or more teeth, the labium is swollen distally except in Pachygnathus, and the male palpus has an elongate, hairy paracymbium which is sometimes branched.
Illustrations. • Pachygnatha clercki. Pachygnatha clercki Sundevall: a, male; b, female, c, profile of cephalothorax and chelicera; d, falcae, maxillae, labium and sternum; e, front view of chelicerae and eyes; f and g, two views of the palpus of the male. From Blackwall (1864). • Pachygnatha listeri. Pachygnatha listeri Sundevall. a, male; b, female; c, the palpus of the male. From Blackwall (1864). • Pachygnatha degeeri. Pachygnatha degeeri Sundevall: a, male; b, female; c, the palpus of the male. From Blackwall (1864). • Tetragnatha sp.. Tetragnatha sp., aff. T. extensa (Linn.). a, male; b, a variety of the male; c, female in its natural posture. See the next image for dissections. From Blackwall (1864: according to Bristowe, there is uncertainty over Blackwall's interpretation of T. extensa). See the next image for dissections. • Tetragnatha sp., dissections. Tetragnatha sp., aff. T. extensa (Linn.). e and f, two views of the palpus of the male; g, chelicerae, maxillae, labium and sternum. From Blackwall (1864; see the previous image).
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’.
