The families of British spiders

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L. Watson and M. J. Dallwitz

Conventional key

If you are serious about identification, you should use the interactive key. It is far superior, with flexible choice of characters, character notes and illustrations, error tolerance, full taxon descriptions, and taxon illustrations.

1(0).
  • The adult spiders with six eyes ... 2
  • The adult spiders with eight eyes... 3

2(1).
  • The eyes clustered almost in a circle ... Dysderidae
  • The eyes all large, closely aggregated anteriorly on the cephalothorax, with the median pair oval and contiguous, flanked by a pair on either side ... Oonopidae
  • The eyes arranged as a pair of separate medians and two pairs of smaller laterals ... Segestriidae
  • The eyes in pairs at the front of the cephalothorax, the two lateral pairs placed obliquely, and the median pair larger and situated transversely ahead of them ... Scytodidae

3(1).
  • Metatarsus IV of the females with a dorsal series of curved bristles (the calamistrum, which is reduced in the males); the abdomen of the females furnished with a plate-like cribellum anterior to the spinnerets (this being reduced in the males) ... 4
  • Metatarsus IV of the females without a calamistrum; the abdomen of the females without a cribellum... 7

4(3).
  • The adults constructing orb webs ... Uloboridae
  • The adults constructing tangled webs... 5
  • The adults constructing horizontal sheet webs... 6

5(4).
  • The eyes in two horizontal rows of 4; the adults constructing neither a terrestrial silken retreat nor an underwater diving-bell; widespread ... Amaurobiidae
  • The eyes comprising four small ones at the extremities constituting a large quadrilateral, with the other four in a small, anterior-median, trapezoid arrangement whose anterior side is shorter and the inner pair of which are the largest of all; the adults constructing a terrestrial retreat in the form of a silk tube; confined to southern England ... Eresidae

6(4).
  • The eyes in two horizontal rows of 4; the adults constructing neither a terrestrial silken retreat nor an underwater diving-bell; widespread ... Dictynidae
  • The eyes comprising four small ones at the extremities constituting a large quadrilateral, with the other four in a small, anterior-median, trapezoid arrangement whose anterior side is shorter and the inner pair of which are the largest of all; the adults constructing a terrestrial retreat in the form of a silk tube; confined to southern England ... Eresidae

7(3).
  • The females carrying egg sacs attached to their spinnerets ... Lycosidae
  • The females carrying egg sacs via their chelicerae and palps... 8
  • The females not carrying egg sacs... 9

8(7).
  • The adults making snare-webs; the eyes in two horizontal rows of 4; the chelicerae fused at the base ... Pholcidae
  • The adults not making snare-webs; the eyes ostensibly in three rows of 4+2+2, the anterior row of four more or less recurved; the chelicerae free at the base ... Pisauridae

9(7).
  • Tarsal claws 2 ... 10
  • Tarsal claws 3... 18

10(9).
  • The tarsi with claw tufts ... 11
  • The tarsi without claw tufts... 17

11(10).
  • The eyes in two horizontal rows of 4 ... 12
  • The eyes ostensibly in three rows of 4+2+2, the anterior row of four more or less recurved ... Zoridae
  • The eyes ostensibly in three rows of 4+2+2, the anterior row of 4 incorporating two enlarged medians, and facing forwards on the square-fronted caput like a battery of car headlamps, with the two rows behind each comprising a pair of small eyes borne dorsilaterally on the top of the caput ... Salticidae

12(11).
  • The eyes all clear and glassy; the first two pairs of legs not laterigrade, the stance and locomotion not crab-like ... 13
  • The eyes all dark; the first two pairs of legs laterigrade... 16

13(12).
  • The anterior spinnerets wide apart ... 14
  • The anterior spinnerets close together... 15

14(13).
  • The tracheal spiracles more or less equidistant from the epigastric furrow and the spinnerets ... Anyphaenidae
  • The tracheal spiracles close to the spinnerets ... Gnaphosidae

15(13).
  • The adults constructing a terrestrial retreat in the form of a silk tube ... Clubionidae
  • The adults constructing neither a terrestrial silken retreat nor an underwater diving-bell ... Anyphaenidae

16(12).
  • The eyes conspicuously ringed with white hairs; the adults lying in wait for their prey; the adult females bright green ... Sparassidae
  • The eyes not ringed with white hairs; the adults actively pursuing their prey; the adult females not bright green ... Philodromidae

17(10).
  • The adult spiders markedly crab-like in stance and locomotion; the eyes all dark; the first two pairs of legs laterigrade; the abdomen angular in shape; the adults lying in wait for their prey ... Thomisidae
  • The adult spiders not crab-like in stance and locomotion; the eyes all clear and glassy; the first two pairs of legs not laterigrade, the stance and locomotion not crab-like; the abdomen smoothly rounded; the adults actively pursuing their prey ... Liocranidae

18(9).
  • the spinnerets all unsegmented ... 19
  • the posterior spinnerets 3-segmented ... Atypidae
  • with one pair of spinnerets 2-segmented... 34

19(18).
  • terrestrial; the adults constructing neither a terrestrial silken retreat nor an underwater diving-bell ... 20
  • fully aquatic, living and hunting in slow-moving or still water, and maintaining a submerged, air-filled bell web as home base; the adults constructing a retreat in the form of an underwater diving-bell, which is kept filled with air ... Cybaeidae

20(19).
  • The adults making snare-webs ... 21
  • The adults not making snare-webs... 30

21(20).
  • The adults constructing orb webs ... 22
  • The adults constructing tangled webs... 26
  • The adults constructing horizontal sheet webs... 27
  • The adults constructing funnel-shaped or tubular webs ... Mimetidae

22(21).
  • The abdomen exhibiting red or pink colour, but neither predominantly bright red and black nor predominantly bright red and yellow; the first two pairs of legs having the tibia and metatarsus armed with long spines, these forwardly-curved towards their tips and increasing in length acropetally along the row, between which are single rows of shorter curved spines ... Mimetidae
  • The abdomen without any red coloration; the first two pairs of legs without the spines characteristic of Mimetidae... 23

23(22).
  • The maxillae longer than broad ... 24
  • The maxillae about as long as broad... 25
  • The maxillae shorter than broad ... Araneidae

24(23).
  • The epigastric furrow nearly straight ... Metidae
  • The epigastric furrow pro-curved between the lung slits ... Tetragnathidae

25(23).
  • The male palps with a well developed paracymbium; the female palps with a claw ... Araneidae
  • The male palps without a paracymbium; the female palps without a claw ... Theridiosomatidae

26(21).
  • The first two pairs of legs having the tibia and metatarsus armed with long spines, these forwardly-curved towards their tips and increasing in length acropetally along the row, between which are single rows of shorter curved spines; the female palps without a claw ... Mimetidae
  • The first two pairs of legs without the spines characteristic of Mimetidae; the female palps with a claw ... Theridiidae

27(21).
  • The male palps with a well developed paracymbium ... 28
  • The male palps without a paracymbium... 29

28(27).
  • Tarsus IV with a ventral row of serrated bristles constituting a ‘comb’ ... Nesticidae
  • Tarsus IV without a ventral ‘comb’ ... Linyphiidae

29(27).
  • The first two pairs of legs having the tibia and metatarsus armed with long spines, these forwardly-curved towards their tips and increasing in length acropetally along the row, between which are single rows of shorter curved spines; the female palps without a claw ... Mimetidae
  • The first two pairs of legs without the spines characteristic of Mimetidae; the female palps with a claw ... Theridiidae

30(20).
  • The first two pairs of legs having the tibia and metatarsus armed with long spines, these forwardly-curved towards their tips and increasing in length acropetally along the row, between which are single rows of shorter curved spines; the abdomen exhibiting red or pink colour, but neither predominantly bright red and black nor predominantly bright red and yellow ... Mimetidae
  • The first two pairs of legs without the spines characteristic of Mimetidae; the abdomen without any red coloration... 31

31(30).
  • The male palps with a well developed paracymbium; widespread ... 32
  • The male palps without a paracymbium; confined to southern England... 33

32(31).
  • The maxillae longer than broad ... Tetragnathidae
  • The maxillae about as long as broad ... Linyphiidae
  • The maxillae shorter than broad ... Linyphiidae

33(31).
  • The eyes comprising a pair of large, circular anterior medians and three smaller laterals in a curved-longitudinal row on either side; the abdomen plain dorsally ... Zodariidae
  • The eyes in a distinctive hexagonal pattern; the abdomen conspicuously patterned dorsally ... Oxyopidae

34(18).
  • The spinnerets in a more or less transverse row ... Hahniidae
  • The spinnerets clustered and superposed ... Agelenidae

To view the illustrations with detailed captions, go to the interactive key. This also offers 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.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. The families of British spiders. Version: 4th January 2012. http://delta-intkey.com’.

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