PHOLCOMMATINAE, 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 : 468

PHOLCOMMATINAE : CLADE 42

Pholcommatinae (see Kaston, 1981: 94) is based on Simon’s (1894) tribal group Pholcommateae, and here includes Enoplognatha , Selkirkiella , Cerocida , Phoroncidia , Stemmops , Pholcomma , Carniella and Robertus .

Unambiguous synapomorphies of the Pholcommatinae include: cymbial hook pointing upwards (34, Figs 66B , 67D, E ), cymbial hook on ectal margin (35, Figs 66B, C , 67E , 92L ), TTA grooved (83, Figs 44C , 60B, C ), portions of E spiral entirely enclosed in TTA (87, Fig. 44C ), E base shifted ectally and partially hidden by cymbium (89, Fig. 60A–C ), AME small (104), PLS AG parallel (218, Figs 45B , 63C, D ).

The composition of this subfamily is uncertain: Phoroncidia , Stemmops and Cerocida all lack some of the unambiguous synapomorphies of the clade, and may be misplaced here (see also Arnedo et al., 2004). Phoroncidia , indeed, lacks many of the theridiid synapomorphies, while some characteristics associate it with the Hadrotarsinae (if all other pholcommatines are removed from the analysis Phoroncidia moves sister to Hadrotarsinae ).

Implied weighing, bootstrapping and taxon removal experiments showed that the Pholcommatinae is the one major clade most sensitive to data perturbations. Thus the current phylogenetic position of at least Phoroncidia , Stemmops and Cerocida should be considered likely to change. Phoroncidia has an unusual combination of characters and sits on a long branch (18 steps, Fig. 103 ). This may in part explain its instability, but the placement of Phoroncidia does not alter when its sister taxon ( Stemmops ) and other closely related taxa (one or more at the time) are removed (but see above). Pholcommatinae may be limited to those taxa with the ectal cymbial hook moderately ( Enoplognatha ) or strongly tapered ( Figs 66B , 67D, E ; in this matrix present in Carniella , Pholcomma , Selkirkiella and Robertus ). Note, however, that Phoroncidia and Stemmops are extremely morphologically diverse and quite possibly nonmonophyletic genera. Given that the exemplar species used in this study are not types, these conclusions may only apply to the species included here.

Based on the synapomorphies of the group it is likely that Craspedisia Simon, 1894 , Helvidia , Proboscidula , Styposis , Theonoe and Wirada belong to this subfamily. All have cymbial hook on ectal margin, pointing upward, and distinctly tapered, and an ectally shifted embolus. Many members of this group have cephalic modifications (proboscis) and prosomal warts.

Figures

Figure 44. Enoplognatha ovata, male. A–E, palp. A, mesial. B, ventral. C, ectal. D, BC-lock mechanism. E, dorsal tibia with three trichobothria (arrows). F, epiandrous gland spigots. G, ridged stridulatory picks. H, stridulatory ridges on prosoma. I, chelicera. Scale bars: A, E, G–I, 100 Mm; B, C, F, 50 Mm; D, 10 Mm.

Figure 45. Enoplognatha, females. A, G–J, E. ovata. B-F, E. latimana. A, spinnerets. B, spinnerets. C, PLS and PMS. D, ALS. E, colulus. F, epigynum, the round, wide openings plugged. G, palpal claw. H, fourth tarsal claws. I, cheliceral retrolateral margin. J, cheliceral prolateral margin. Scale bars: A–E, 50 Mm; F, 100 Mm; G-J, 10 Mm.

Figure 60. Pholcomma hirsutum, male. A–D, palp. A, mesial. B, ventral. C, ectal. D, CB-lock mechanism; note scoop shaped hood of MA (79-1) and tapering tip of cymbial hook (CHk, 37-1). E, pedicel area of abdomen; note a pair SP (arrows). F, stridulatory ridges of the prosoma. G, prosoma. H, cheliceral teeth. Scale bars: A–C, E, F, H, 50 Mm; D, 10 Mm. G, 100 Mm.

Figure 63. Phoroncidia sp. A–C, female. A, epigynum. B, spinnerets; note sclerotized ring around them (202-1). C, close-up of spinnerets. D-H, male. D, spinnerets. E, fourth tarsus. F, leg I; short and sturdy legs are typical for the genus. G, colular setae. H, abdominal apodeme. I, tip of female palpal tarsus, claw absent (176-1). Scale bars: A, 20 Mm. B, F, 100 Mm. C, D, 10 Mm. E, G-I, 50 Mm.

Figure 66. Robertus lividus. A–C, male palp; note that nomenclature of palpal sclerites is uncertain. A, mesial. B, ventral; note strongly tapered tip of the cymbial hook (Chk, 37-1). C, ectal; note single trichobothrium on tibia (arrow, 18-2, 19-2). D, male prosoma. E, male fourth tarsal claws. F, male chelicera. G, prosomal stridulatory ridges. H, female spinnerets. Scale bars: A–D, G, 100 Mm. E, F, H, 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 92. Schematic illustrations of palpal cymbia. A, Argiope argentata. B, Tetragnatha extensa. C, Nesticus reclusus. D, Steatoda americana. E, Argyrodes argyrodes. F, Anelosimus studiosus. G, Thymoites sp. H, Anelosimus vittatus. I, Ameridion nr. petrum. J, Euryopis sp. K, Thwaitesia sp. L, Selkirkiella alboguttata. M, Spintharus flavidus. Note that trichobothria are omitted in G, H and M.

Figure 103. Cladogram of outgroups and basal theridiids. Clade numbers in circles at nodes; other Pholcomma numbershirsutum indicate characters changing on those nodes; underlined characters have perfect fit to the cladogram. Numbers on terminal branches are branch lengths (steps) when different from zero. All changes are shown cf. chickeringi