Anelosimus, Simon, 1891

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 : 469-470

ANELOSIMUS : CLADE 24

As predicted by Forster et al. (1990), the results strongly refute the monophyly of Anelosimus sensu lato (which included Kochiura and Selkirkiella ) ( Fig. 102 ). None of the 17 Chilean species currently placed in Anelosimus seem to belong there; they differ in many key characteristics from the type species A. eximius , such as plesiomorphic retention of the hooked cymbial notch ( Fig. 67B, D, E ), hooded MA ( Fig. 67D ), and colulus ( Fig. 68F ). Some Chilean ‘ Anelosimus ’ are clearly pholcommatines ( A. alboguttatus and A. magallanes are here transferred to the resurrected pholcommatine Selkirkiella , clade 39), based for example, on cymbial hook position and its structural details (34, 35, 37, Fig. 67D ), embolus position (89, Fig. 67B ), and spinneret spigot morphology (216, Fig. 68D, E ) (see Taxonomy section). Others belong to a clade containing the European A. aulicus , whose placement in Anelosimus is also refuted ( A. aulicus and A. roseus are sister to the lost colulus clade and are here transferred to the resurrected Kochiura , clade 26; see Taxonomy section).

As circumscribed here, the monophyly of Anelosimus rests on only one unambiguous synapomorphy: ridges on the surface of the epigynal plate (3, Figs 19B , 21G , 93F ). Bremer support for the clade is low (1), the clade is sensitive to data perturbation, and making clade 23 sister to Theridiinae involves only one step. On the other hand, clade 18, which contains the ‘classical’ new world Anelosimus , is well supported (Fig. 104). Many new species have come to light (for example, from Madagascar; pers. observ.), and the taxonomy will probably change as new data are added.

Theridiinae is well defined (see below) and easily diagnosed, including all nonhadrotarsine theridiids without any trace of colulus. The inclusion of Anelosimus in Theridiinae would muddle the diagnosis of the subfamily and add to what is already the largest theridiid subfamily. As the position of Anelosimus outside the lost colular setae clade is corroborated by molecular evidence ( Arnedo et al., 2004), I do not include it in Theridiinae . The placement of Kochiura is uncertain; here it is outside the lost colulus clade, while in Arnedo et al. (2004) it is sister to Anelosimus . The subfamily placement of Kochiura and Anelosimus thus awaits future combined analysis. The results suggest dual origin of quasisociality within Anelosimus (see ‘Sociality’, below).

THERIDIINAE (LOST COLULAR SETAE CLADE): CLADE 15

Yoshida (2001a: 158) defined Theridiinae based on two synapomorphies: ‘paracymbium of male palpus hooded’ and ‘colulus usually absent’ and synonymized Spintharinae with it. Yoshida’s Theridiinae is apparently not monophyletic and is redefined here, while Spintharinae is again recognized (see above).

Theridiinae (including at least Achaearanea , Ameridion , Chrysso , Helvibis , Nesticodes , Theridion , Theridula, Thymoite and Tidarren ) is well supported in this study. It is unambiguously defined by: a reduction in both retrolateral (18, with some reversals within the subfamily) and prolateral trichobothria (19) on the male palpal tibia ( Figs 85B , 86B ), epiandrous gland spigots spread over genital plate (169, Figs 58E , 76F , 77G ), and absence of colular setae (no trace of colulus, 174, Fig. 78A ). In addition, most species in this clade have notably long and thin legs.

Other nonhadrotarsine theridiid genera lacking the colulus probably belong here, including Achaearyopa Barrion & Litsinger, 1995 , Cabello Levi, 1964 , Cephalobares O. P.-Cambridge, 1870, Cyllognatha L. Koch, 1872 , Echinotheridion Levi, 1963 , Exalbidion Wunderlich, 1995 , Histagonia Simon, 1895 , Jamatid- ion Wunderlich, 1995, Keijia , Macaridion Wunderlich, 1992 , Molione Thorell, 1892 , Neottiura , Nipponidion Yoshida, 2001 , Paratheridula Levi, 1957 , Propostira Simon, 1894 , Rugathodes Archer, 1950 , Sardinidion Wunderlich, 1995 , Simitidion Wunderlich, 1992 , Takayus Yoshida, 2001 , Tekellina Levi, 1957 , Wamba O. P.-Cambridge, 1896, and perhaps others.

This group is similar to the colulus-less group discussed by Levi & Levi (1962). About half of theridiid species belong to Theridiinae ; the group is therefore relatively poorly understood. Most genera still have no identified synapomorphies and relatively few appear to be monophyletic. The name Theridiinae refers to Simon’s tribal group Theridieae, which was based on Theridion and related genera.

Figures

Figure 19. Anelosimus eximius. A, epiandrous gland spigots. B, epigynum; note ridges on epigynal plate (arrows, 3-1). C, prolateral cheliceral margin. D, retrolateral cheliceral margin. E, male fourth tarsal claws. F, female prosoma. Scale bars: A, C–E, 20 Mm; B, 50 Mm; F, 100 Mm.

Figure 21. Anelosimus cf. jucundus. A–F, male. A, SPR. B, sternum. C, fourth tarsal claws. D, posterior margin of prosoma, lacking regular stridulatory ridges, but with patches of irregular rugosity (128-0). E, details of the irregular, possibly stridulatory, surface. F, epiandrous gland spigots. G, epigynum. Scale bars: A, C, 50 Mm; B, D, G, 100 Mm; E, F, 20 Mm.

Figure 58. Nesticodes rufipes. A, B, male palp. A, mesial. B, ventral. C, stridulatory picks (pedicel area artificially shaded). D, stridulatory ridges. E, epiandrous gland spigots. F, male fourth tarsal claws. G, female palpal claw. Scale bars: A–D, 100 Mm; E–G, 20 Mm.

Figure 67. Selkirkiella sp. A–D, male palp. A, mesial; note knob on the TTA (lowest arrow, 82-1). B, ventral, left arrow shows TTA knob. C, ectal; note two trichobothria on tibia (arrows, 18-2, 19-1). D, subapical; note hood on MA (78-1) and the complementary cymbial hook (Chk, 33-0), on the cymbial margin (35-1). The highly tapered tip (37-1) is a synapomorphic condition for a group within Pholcommatinae (tapered cymbial hook clade). The E is visible tightly wrapped by the C, and the TTA (87-1). E, details of the upward pointed (34-1), tapered, cymbial hook. F, stridulatory area of abdomen; note a pair of SP, and numerous nubbins and ridges (155-1). G, H, S. magallanes. G, prosoma stridulatory ridges. H, pedicel; note slit sensilla (Ss) and nubbins. Scale bars: A–D 100 Mm. E, F, 20 Mm. G, H, 50 Mm.

Figure 68. Selkirkiella magallanes. A, B, D–F, female. A, labium (la) and tips of chelicera. B, cheliceral promarginal teeth. C, epiandrous gland spigots. D, spinnerets. E, PLS. F colulus (arrow). G, epigynum. Scale bars: A, D–G, 100 Mm. B, 20 Mm. C, 50 Mm.

Figure 76. Theridion frondeum. A, male SPR. B, male prosoma front view; note humps on chelicera (arrow, 115-1). C, female fourth tarsal claws; note elongated central claw (200-1) and the similarity of the serrated bristles of the tarsal comb (Tc, 195-1) to the accessory claws (Acl). D, palpal claw. E, promarginal cheliceral teeth. F, epiandrous gland spigots. G, male spinnerets; note absence of a functional triplet (arrows, 219-0). Scale bars: A, B, 100 Mm. C, 10 Mm. D, F, 20 Mm. E, G, 50 Mm.

Figure 77. Theridion longipedatum, male. A–C, palp. A, mesial; note multifurcated MA (76-1, 77-1). B, ventral; note placement of the C apically on T (69-1), as opposed to the more common placement on T margin (69-0). C, ventral close-up; note outgrowth of T, harbouring the tegular pit (Tp, 49-1), the embolus has an apophysis fitting under it (arrow, 50-1, 98-1). D, prosomal stridulatory ridges. E, abdominal SPR. F, abdomen venter, with ‘sclerotized ring around pedicel’ (147-1, 148-1) swollen area around pedicel reaching to the epigastric furrow. G, epiandrous gland spigots. Scale bars: A–F, 100 Mm. G, 50 Mm.

Figure 78. Theridion longipedatum. A–D, spinnerets. A, all. B, PMS. C, ALS; note unusual presence of two major ampullate spigots (MAP), no doubt teratological, as other specimens inspected had a single MAP, see e.g. D. D, male left field, arrows indicate AG scars (nonfunctional triplet, 219-0). E, female fourth tarsal comb. F, cheliceral promarginal teeth (arrows, 106-1). G, anterior part of male prosoma; note basal protrusions on chelicera (arrow, 115-1), a feature of many Theridion spp. and also, e.g. Coleosoma. Scale bars: A, D, G, 100 Mm. B, C, E, 20 Mm. F, 50 Mm.

Figure 85. Thymoites unimaculatum. A, B, male palp. A, ventral; note membranous Cb (67-1), rising from the apical part of the T. B, ectal; note single trichobothrium on tibia (arrow, 18-2, 19-2). C, male SPR left side. D, ditto, both sides; note asymmetry in numbers. E, epiandrous gland spigots. F, epigynum. G, spinnerets. Scale bars: G, 100 Mm; A, B, F, 50 Mm; C, D, 20 Mm; E, 10 Mm.

Figure 86. Tidarren sisyphoides. A–F, highly modified male palp. A, ventral, close-up. B, ectal from below; note single trichobothrium (arrow). C, ectal. D, apical; note extremely modified cymbium. E, dorsal. F, details of cymbial ridges (23-2), and the tarsal organ. G, epigynum. Scale bars: A, 50 Mm; B–E, G, 100 Mm; F, 20 Mm.

Figure 93. A–D, models of male sperm duct trajectory. A, Anelosimus eximiu: ectal view, numbers indicate where the duct completes loops 1-3. B, A. eximius, dorsal view. C. Theridion. D, Faiditus. E-J, schematic illustrations. E, Faiditus chickeringi, ducts. F, Anelosimus rupununi, epigynum. G, Kochiura aulica, epigynum. H, A. rupununi, internal female genitalia. I, Dipoena nigra, internal female genitalia. J, Kochiura aulica, internal female genitalia. (F–H & J, drawn by Sarah Crews.)

Figure 102. Single most parsimonious cladogram (L = 759, CI = 37, RI = 73) and preferred phylogenetic hypothesis of theridiid spiders with major groups identified and the family Theridiidae shown with thick lines. Numbers above branches indicate Bremer support; below branches are bootstrap values (above 50%). Parsimony jackknife scores were nearly identical and are not shown.