Anelosimus nelsoni Agnarsson

Agnarsson, Ingi & Zhang, Jun-Xia, 2006, New species of Anelosimus (Araneae: Theridiidae) from Africa and Southeast Asia, with notes on sociality and color polymorphism, Zootaxa 1147, pp. 1-34 : 26-28

Anelosimus nelsoni Agnarsson n. sp.

( Figs 14A–C , 15A–F , 16A–G , 17A–F )

Types

Male holotype and paratype (1 Ψ) from South Africa, Kwazulu Natal St. Lucia Estuary, Fanies Island, 5 km S of Cape Vidal, 28°06’41”S, 32°25’51”E 5.iv. 2001,I. Agnarsson et al., deposited in NMNH

Diagnosis

Anelosimus nelsoni n. sp. males can be separated from other Anelosimus by the shape of the large and bifurcate ‘embolic division b’, and the conspicuous hook on the distal portion of the embolus base ( Figs 14A , 15B–D ). Females differ from all other Anelosimus by the copulatory duct wrapping the spermathecae ( Fig. 14C ).

Description

Male (holotype): Total length 2.08. Prosoma 1.20 long, 0.90 wide, pale yellowish, center and a narrow rim dark. Sternum 0.75 long, 0.60 wide,, pale yellowish, lightest in center. Opisthosoma 1.10 long, 0.90 wide, 0.90 high. Pattern other Anelosimus . Eyes subequal in size about 0.07 in diameter. Clypeus height about 2.3 times AME diameter. Leg I femur 1.60, patella 0.50, tibia 1.55, metatarsus 1.40, tarsus 0.62. Femur about 6 times longer than wide. Leg formula 1423. Leg pale yellowish, narrow dark rings near all joints (except coxae–trochanter). 4–7 small trichobothria dorsally on all tibia, 5–6 on tibia I, 6 on tibia III. 2 prolateral and 1 retrolateral trichobothrium on palpal tibia. Stridulatory pick row on opisthosoma distinctly curved, with distal setae compressed, consisting of approximately 27–32 modified setal bases ( Figs 16E–F ). Epiandrous gland spigots in two distinctly separate groups with approximately 6–7 fusules ( Fig. 16C ).

Palpal organ as in Figures 14A , 15A–F .

Female (paratype): Total length 2.60. Prosoma 1.40 long, 1.00 wide, pale yellowish, center and a narrow rim dark. Sternum 0.90 long, 0.65 wide, pale yellowish, lightest in center. Opisthosoma 1.45 long, 1.25 wide. Pattern as in other Anelosimus . Eyes subequal in size about 0.07 in diameter. Clypeus height about 2.5 times AME diameter. Leg I femur 1.60, patella 0.50, tibia 1.35, metatarsus 1.25, tarsus 0.60. Femur about 6 times longer than wide. Leg formula 1423. Leg pale yellowish, narrow dark rings near all joints (except coxae­trochanter). 5–6 small trichobothria dorsally on all tibia, 5–6 on tibia I, 5 on tibia III. 4 dorsal trichobothria on palpal tibia on one side ( Fig. 17E ), 3 on the other. Epigynum as in Figures 14B–C , 16A–B .

Distribution

Only known from the type locality.

Natural history

This species was collected beating bushes and trees during day. Webs were not seen. The habitat was a small, open, forest patch, situated on a small river island.

Phylogenetics

Anelosimus nelsoni n. sp. was included in the phylogenetic analyses of Agnarsson (2005, 2006) as Anelosimus sp. 5 South Africa. In these analyses A. nelsoni n. sp. was sister to the ‘epigynal scape clade’ (see Agnarsson 2006), together these form a clade here termed the ‘basal cymbial hood clade’ ( Fig. 1 ), referring to a synapomorphy shared by all species in it ( Fig. 15F ).

m.

Figures

FIGURE 1. Summary cladogram of Anelosimus species based on Agnarsson (2005, 2006). The approximate placement of the ‘ agnar group’ (A. agnar n. sp. and A. linda n. sp.), indicated with an arrow, is based on preliminary molecular data (Agnarsson unpublished). Alternatively the agnar group may belong to the filiform embolus clade. In Agnarsson (2005, 2006) A. sp. 2 Tanzania = A. biglebowski n. sp, A. sp. 3 Tanzania = A. dude n. sp., A. sp. 4 Singapore = A. kohi Yoshida, 1993, and A. sp. 5 South Africa = A. nelsoni n. sp. Preliminary morphological evidence such as filiform embolus, tegular ridge, and voluminous spermathecae (see Agnarsson 2006 for details) further indicate the placement of A. monskenyensis n. sp., A. sulawesi n. sp., A. chonganicus Zhu, 1998, A. crassipes (Bösenberg & Strand, 1906), A. dubius (Tullgren, 1910), A. exiguus Yoshida, 1986, A. iwawakiensis Yoshida, 1986, and A. taiwanicus Yoshida, 1986 in the ‘ filiform embolus clade’.

FIGURES 14 A – C. Anelosimus nelsoni n. sp. A, male pedipalpus, ventral (C conductor, E embolus, EB ‘ embolic division b’, MA median apophysis, TTA theridiid tegular apophysis); B, epigynum, ventral; C, epigynum cleared, dorsal (CD copulatory ducts, FD fertilization ducts, S spermathecae), line sketch above shows trajectory of the copulatory ducts to the spermathecae. Scale bars (left for pedipalpus, right for epigyna): 100 m.

FIGURES 15 A – F. Anelosimus nelsoni n. sp., male pedipalpus, slightly expanded (C conductor, E embolus, Eb ‘ embolic division b’, MA median apophysis, SC subconductor, ST subtegulum, T tegulum, TTA theridiid tegular apophysis). A, prolateral; B, prolateral­ventral; C, ventral; D, retrolateral­ventral; E, retrolateral; F, details of pedipalpus, retrolateral, showing basal cymbial hood (arrow), the saw­toothed edge may be a basal part of the TTA. Scale bars: A – E, 100 m; F, 50

FIGURES 16 A – G. Anelosimus nelsoni n. sp. A, epigynum, ventral; B, same, caudal; C, epiandrous gland fusules; D, female stridulatory pick row; E, male opisthosoma, pedicel area, ventral; F, male stridulatory pick row, left side; G, female left spinning field (ALS anterior lateral spinneret, PLS posterior lateral spinneret, PMS posterior median spinneret). Scale bars: A – B, D – E, G, 100 m; C, F, 10 m.

FIGURES 17 A – F. Anelosimus nelsoni n. sp. A, female prosoma, dorsal; B, same, lateral; C, male sternum, ventral; D, male tarsus I tip, lateral; E, female pedipalpal tibia, dorsal, with four trichobothria (the other pedipalpal tibia of the same animal had only three); F, female opisthosoma surface, near center laterally. Scale bars: A – C, F, 100 m; E, 50 m; D, 10 m.