Admesturius bitaeniatus (Simon, 1901)

Barry J. Richardson, 2010, A Review of the Jumping Spider Fauna (Araneae: Salticidae) of Chile, Zootaxa 2418, pp. 1-49 : 8-9

Admesturius bitaeniatus (Simon, 1901)

Figs 4–10

Admestina bitaeniata Simon, 1901a: 615 , 624; 1902: 28; Galiano, 1962a: 68; 1963: 283, pl. 3, figs 1–3, 9; 1988: 295, figs 5, 9–10, 19.

Material examined. CHILE: 2♀, 10km E Los Quenes , 70.80°W, 35.02°S, 10 March 2003, J.E. Barriga, fogging ( BJR978 , CAS) ; 1♀, Curico, El Coihue, 20km E Potrero Grande , 70.97°W, 35.18°S, 28 September 2003, J.E. Barriga-Tunon et al., fogging ( BJR1055 , CAS) ; 1♀, Curico, El Coihue, 20km E Potrero Grande , 70.97°W, 35.18°S, 7 November 2003, J.E. Barriga-Tunon et al., fogging ( BJR1000 , CAS) ; 13, Curico, El Coihue, 20 km E Potrero Grande , 70.97°W, 35.18°S, 7 November 2003, J.E. Barriga-Tunon et al., fogging ( BJR977 , CAS) ; 3♀, 63, Curico, El Coihue, 20 km E Potrero Grande , 70.97°W, 35.18°S, 23 November 2003, J.E. Barriga-Tunon et al., fogging ( BJR104 , CAS) ; 1♀, Curico, El Coihue, 20km E Potrero Grande , 70.97°W, 35.18°S, 25 November 2003, J.E. Barriga-Tunon et al., fogging ( BJR967 , CAS) ; 13, Curico, El Coihue, 20km E Potrero Grande , 70.97°W, 35.18°S, 25 November 2003, J.E. Barriga-Tunon et al., hand collecting ( BJR997 , CAS) ; 13, Curico, El Coihue, 20km E Potrero Grande , 70.97°W, 35.18°S, 25 November 2003, J.E. Barriga-Tunon et al., fogging ( BJR1052 , CAS) ; 13, Curico, El Coihue, 20km E Potrero Grande , 70.97°W, 35.18°S, 30 December 2003, J.E. Barriga-Tunon et al., fogging ( BJR971 , CAS) ; 3♀, Curico, El Coihue, 20km E Potrero Grande , 70.97°W, 35.18°S, 26 March 2007, J.E. Barriga-Tunon et al., fogging ( BJR1045 , CAS) ; 1♀, 13, Cauquenes, Los Rules, 20 km W Cauquenes , 72.35°W, 35.88°S, 1 October 2003, J.E. Barriga-Tunon et al. ( CAS, BJR969 ) ; 4♀, 43, 5imm, Malalcahuello Way, Lonquimay , 71.52°W, 38.43°S, 19 January 2007, fogging, Araucaria ( BJR1010 , CAS) ; 1♀, Comunidad Indigena Quinquen , 71.38°W, 38.63°S, 6 March 2008, E. Arias et al., fogging, Araucaria ( BJR1090 , CAS) ..

Diagnosis. The two species of this genus are most simply distinguished by the markedly different patterns on the abdomens found in both sexes. In A. bitaeniatus , this consists of a pair of parallel lines of dark patches ( Figs 4–5 ) unlike the pattern of scattered patches seen in A. schajovskoyi ( Figs 11–12 ). The area between the parallel lines is occasionally so dark as to give the impression of a single large dark area. In the males the shapes of the more ventral of the two apophyses has a club-shaped end sometimes tending to hook-shaped. In the females, the epigynum has two straight, slit-like fossae, angled away from the median line and distinctive, well separated copulatory openings. Insemination ducts are long and convoluted, spermathecae subdivided into compartments.

Description. Male: Body form flattened. Cephalothorax tan colour with its lower margin darker. A pair of darker patches on the pars cephalica, often in an underlying background of extensive white guanine deposits. A lateral band of white hairs along each side of the cephalothorax. Surrounds of ALE, PME and PLE, black. Clypeus short, mid-dark brown with a white fringe of hairs. Chelicerae vertical, yellow-orange, with five promarginal teeth and one retromarginal tooth. Endites and labium yellow-brown. Sternum yellow. Abdomen yellow, with two dorsal parallel longitudinal bands made from darker semi-contiguous patches ( Fig. 5 ) and with an overall pattern of small black spots ( Fig. 5 ). Often a faint pattern of inverted V shaped bands posteriorly and a distinct brown scutum. The area between the parallel lines is occasionally so dark as to give the impression of a single large black area. Ventral surface light with a scatter of darks spots and extensive white guanine deposits, occasionally entire surface of abdomen darker. Spinnerets yellow with dark spots on the undersurface. L1 much larger and heavier than the other legs, femur, patella, tibia dark brown, without spines. Metatarsus yellow with two pairs of ventrolateral spines. Other legs yellow with brown markings, tibia and metatarsus with three and two pairs of ventrolateral spines, respectively. Palp ( Figs 8–9 ): tibia with two apophyses, ventral one with distinctive club shaped end sometimes tending to hook shape. Tegulum without lobe, rounded, embolus medium length, not coiled, set in crater-like depression. Dimensions: CL 1.540.0 5 (5), EFL 0.64+0.03 (5), CW 1.00+0.07 (5), AEW 0.85+0.07 (5), AMEW 0.61+0.05 (5), PEW 0.90+0.06 (5), SL 0.66+0.07 (5), (P4+T4) 0.91+0.06 (4).

Female: Colouration as in the male, except abdominal band usually stronger and other markings missing ( Fig. 4 ). All legs yellow with occasional darker markings. L1 not as heavily built as in the male and tibia and metatarsus with one and two pairs of ventrolateral spines, respectively. Spination on other legs as in the male. Epigynum ( Figs 6–7 ): a sclerotised, distinct, dark brown plate with a median posterior notch and a pocket in the posterior edge of the epigynum. Two straight, slit-like fossa angled away from the median line with distinctive, well separated copulatory openings. Insemination ducts long and convoluted, spermathecae subdivided into compartments ( Fig. 6 ). Dimensions: CL 1.61+0.06 (5), EFL 0.71+0.03 (5), CW 1.050 (5), AEW 0.930 (5), AMEW 0.63+0.03 (5), PEW 0.97+0.03 (3), SL 0.680 (5), (P4+T4) 1.03+0.09 (5).

Biology and distribution. The flattened body form and reduced spination implies that the species lives under bark. In general form it is similar to the Australian genus Holoplatys ( Zabka 1991) . The species is distributed widely in Chile ( Fig. 10 ) and was found on Araucaria and Nothofagus trees. An earlier report of the species in Argentina ( Galiano 1962a) is of A. schajovskoyi ( Galiano 1988) .

Figures

FIGURES 4 – 10. Admesturius bitaeniatus. 4 – 5 dorsal view (4 female, 5 male); 6 – 7 female genitalia (6 dorsal view of cleared specimen, 7 ventral view of external characteristics); 8 – 9 male palp (8 ventral view, 9 lateral view); 10 known distribution. Scales: total body 1 mm; remainder 0.2 mm

FIGURES 11 – 17. Admesturius schajovskoyi. 11 – 12 dorsal view (11 female, 12 male); 13 – 14 female genitalia (13 dorsal view of cleared specimen, 14 ventral view of external characteristics); 15 – 16 male palp (15 ventral view, 16 lateral view); 17 known distribution. Scales: total body 1 mm; remainder 0.2 mm