NESTICIDAE, SIMON, 1894

Agnarsson, Ingi, 2004, Morphological phylogeny of cobweb spiders and their relatives (Araneae, Araneoidea, Theridiidae), Zoological Journal of the Linnean Society 141 (4), pp. 447-626 : 465

THERIDIOIDS ( NESTICIDAE , THERIDIIDAE ): CLADE 55

Theridioids are supported by several unambiguous synapomorphies, including: reduced number of epiandrous gland spigots (170, Figs 14F, G , 22F ), exactly two colular setae (175, Fig. 9D , reversed to three or more in latrodectines, Fig. 55H ), lobed PLS AG glands (217), cobweb (225, Figs 96D–F , 99A, B , 100A–F , 101A–F ), and sticky silk on gumfoot lines (227, Figs 96F , 97B–D , 101B, D ).

Figures

Figure 9. Euryopis and Emertonella. A–D, spinnerets. A, B, female Euryopis flavomaculata. A, all. B, ditto, left spinning field; note ridges on ALS (203-1) and the absence of FL on PLS (212-1). C, D, Emertonella funebris male. C, left field; note presence of functional AG (219-1). D, colular setae; note invagination of the colular area (vertical arrow, 172-2), and the pair of long colular setae (horizontal arrows). E, E. flavomaculata palpal claw; the palmate condition (177-1) is a synapomorphy of Hadrotarsinae. F, ditto, cheliceral fangs. Scale bars: A, B, E, F, 50 mm; C, D, 20 mm.

Figure 14. Ameridion nr. petrum. A, ventral side of abdomen; note SPR (arrow, 150-1). B, promarginal cheliceral teeth (106-0). C, front view of male prosoma; note enlarged AM eyes. D, female spinning field. E, female fourth tarsus. F, epiandrous gland spigots. G, Ameridion sp., epiandrous gland spigots. Scale bars: A, C, 100 mm; B, D–G, 10 mm.

Figure 22. Anelosimus rupununi. A–D, male palp. A, mesial; note bifurcated MA (75-1). B, ventral. C, ectal. D, distal tip. E, cheliceral promarginal teeth. F, epiandrous gland spigots. G, epigynum; note acute upper wall of bursa (arrow, 6-1). Scale bars: A–D, 100 Mm; G, 50 Mm; E, F, 20 Mm.

Figure 55. Latrodectus geometricus. A–E, female. A, epigynum. B, fourth tarsal claws and accessory claws (Acl). C, ALS. D, PMS and PLS. E, cheliceral claws. F–H, male. F, epiandrous gland spigots (arrows). G, right spinning field, the triplet is nonfunctional (arrow, 219-0). H, details of a fleshy, triangular colulus (172-0, 173-0), bearing two basal and one central setae (arrows, 174-0, 175-0). Scale bars: A, B, E, 100 Mm; C, D, 50 Mm; F, G, 20 Mm; H, 10 Mm.

Figure 96. Latrodectus female and web. A, Latrodectus sp., ventral view (Phinda, S-Africa). B, ditto, dorsal view. C–F, L. geometricus web (Berenty reserve, Madagascar). C, female in retreat of web, located in a crevice on a tree trunk about 1.5 m above the ground. D, the retreat opens to a domed sheet, that leads down nearer to the ground. E, 20-30 cm above the ground the sheet turns into a typical cobweb mesh, from which gumfoot lines lead to the ground. F, tips of gumfoot lines (227-1); this trapping area of the web is nearly 2 m away from the female’s retreat.

Figure 97. A, Episinus sp. in web (225-4), posterior line held with one leg IV; leg pairs I, II both holding on to the line in front of the animal (Perinét, Madagascar). B–D, Phoroncidia spp., simple line webs (225-6). B, typical posture of a single line web, the spider holding on to dry silk near substrate; note transition to sticky silk (Ranamofana, Madagascar). C, similar position to Episinus, but uses only single leg I to hold line in front of the animal (Puyehue, Chile). D, closer. E, Thwaitesia sp. habitus (Sodwana Bay, S. Africa). F, Tidarren sp. (Fanies Island, S. Africa); note characteristic thin white band on abdomen. G, ditto, web.

Figure 99. Webs and habitus of species all previously in Anelosimus. A, Kochiura attrita web (Puyehue, Chile, 225-3). B. Selkirkiella luisi web (Puyehue, Chile, 225-3, 226-1). C. Anelosimus eximius web (Kaieteur falls, Guyana, 225-1). D, A. eximius female, standing on the dense mat of silk which forms the dome of the web (Bartika, Guyana). E, Selkirkiella luisi, female habitus (Puyehue, Chile). F, Kochiura sp., female habitus (Puyehue, Chile).

Figure 100. Achaearanea spp. webs. The ‘star-shaped’ web (225-3, 226-0, 227-1) of all species displayed here is typical of many Achaearanea and has also been reported in some Theridion and Chrysso. A–C from Gunn’s Landing, Guyana. D from Ranamofana, Madagascar. E, F from Fanies Island, S. Africa. This web structure will no doubt be of use in further phylogenetic studies on Theridiinae. Some species consistently have a leaf retreat in the web’s centre (E, F).

Figure 101. A–D, ‘nonstar’ Achaearanea spp. webs (225-3, 226-0, 227-1). A, platform and gumfoot lines, surrounding a tree trunk (Ranamofana, Madagascar). B, ditto, gumfoot lines. C, gumfoot lines radiating in several directions, attached to a tree trunk and surrounding leaves (Ranamofana, Madagascar). D, ditto, gumfoot lines. E, Achaearanea sp. web covered with flies that use silk lines for resting (Fanies Island, S. Africa), the extremely simple, nonsticky, web of the argyrodine Ariamnes helps to lure nematocerous flies into proximity with the spider. F, Theridion sp., egg sac is protected in a special (nonsnare) web (Fanies Island, S. Africa). G, Chrysso sp. female and egg sac (Fanies Island, S. Africa).