Anelosimus studiosus (Hentz, 1850)

Agnarsson, Ingi, 2006, A revision of the New World eximius lineage of Anelosimus (Araneae, Theridiidae) and a phylogenetic analysis using worldwide exemplars, Zoological Journal of the Linnean Society 146 (4), pp. 453-593 : 471

THE STUDIOSUS GROUP – CLADE 5

F. O. P.- Cambridge (1902) described a variable and widespread A. studiosus , but commented that the variation could indicate several similar species (see quote at beginning of this chapter). Levi (1956) agreed with F. O. P.- Cambridge’s (1902) previously suggested synonymies, and added Enoplognatha dubia and A. fraternus . The species thus became even more variable and widespread, from Argentina to northeastern United States (e.g. Washington, DC), and from a wide range of altitudes (0–4000 m) and habitats (e.g. tropical forest, temperate scrub). In a section called ‘subspecies’ Levi (1956: 419) commented on, and illustrated, the considerable geographical variation in size and genitalic, especially palpal, morphology of his A. studiosus . Given the complexity of Anelosimus taxonomy, and virtual absence of behavioural data, Levi understandably preferred to treat all these taxa as one species. However, in addition to differences in morphology, recent studies indicate differences in behaviour (including different levels of sociality) and barriers to breeding (failed breeding experiments) between several geographically separated populations ( Brach, 1977; Furey, 1998; Jones & Parker, 2002; L. Avilés, pers. comm.). With access to much more material, and armed with new behavioural observations, it seems now that Levi’s (1956) A. studiosus is rather a species complex, including at least eight species. The studiosus group (see Fig. 59 , clade 5) is here supported by two unambiguous synapomorphies: closely arranged sclerotized copulatory ducts (10 -1, Fig. 44D ), and a snout-like Eb (75 -1, Figs 44A, F , 49B, H, K, L ).

Figures

Figure 44. The ‘studiosus group’. A–E, Anelosimus elegans. A, male palp mesal; B, same ventral; C, epigynum; D, internal epigynum dorsal; E, digital photograph of male holotype. F–O, Anelosimus guacamayos. F, male palp mesal; G, same ventral; H, male palp lacking distal E fork; I, epigynum; J, epigynum, female collected with ‘forkless’ male; K, internal epigynum dorsal; L, female habitus dorsal; M, male habitus dorsal; N, female habitus ectal; O, subadult male habitus ectal.

Figure 49. The studiosus group. A–F, Anelosimus studiosus. A, mesal view of male palp; B, ventral view of male palp; C, epigynum; D, internal epigynum dorsal; E, male habitus dorsal; F, female abdomen dorsal. G–J, Anelosimus pantanal. G, male palp mesal; H, same ventral; I, epigynum; J, internal epigynum dorsal. K–N, Anelosimus fraternus. K, male palp (holotype) mesal; L, same ventral; M, epigynum; N, internal epigynum dorsal.

Figure 59. The preferred phylogeny with informal clade names and clade numbers in circles at the nodes.