Thaida chepu Platnick, 1987

Michalik, Peter & Ramirez, Martin J., 2013, First description of the male of Thaida chepu Platnick, 1987 (Araneae, Austrochilidae) with micro-computed tomography of the palpal organ, ZooKeys 352, pp. 117-125 : 118-120

Thaida chepu Platnick, 1987

Material examined.

CHILE: Region de Los Lagos (X), Chiloé province, Isla de Chiloé, Lago Huillinco, N margin, 4.6 km (air) ESE Cucao, 42.64117°S, 74.04763°W (GPS, ± 100m), elev. 12 m (MJR-loc-86), 16 February 2012, 1 male, coll. K. Huckstorf, M. Izquierdo, P. Michalik, M. J. Ramirez, C. S. Wirkner (ZIMG II/28126).

Diagnosis.

Similar to Thaida peculiaris by the clypeus about three times the diameter of the anterior median eyes (Fig. 3); males distinguished from Thaida peculiaris by the copulatory bulb, which has the median apophysis longer than the embolus (Figs 5-10; about half the length of the embolus in Thaida peculiaris , Forster et al. 1987, figs 155-157), a stout and curved process of the subtegulum (slender and straight in Thaida peculiaris , Forster et al. 1987, figs 155-157), and the bent embolus with a curved tip (embolus of Thaida peculiaris without distinct tip, Forster et al. 1987, figs 155-157). Diagnosis of the female in Forster et al. (1987).

Description.

Male (ZIMG II/28126). Carapace 5.59 long and 4.38 wide; clypeal height 0.68 (in the middle about three times AME diameter in height; Fig. 3); coloration as depicted in Fig. 4. Eye sizes and interdistances: AME 0.24, ALE 0.31, PME 0.25, PLE 0.30; AME-AME 0.05, AME-ALE 0.15, PME-PME 0.26, PME-PLE 0.22, ALE-PLE 0.06; MOQ length 0.77, median ocular quadrangle width 0.78. Spination: femora: I d 1-0-1, p 2-3-3, r 2-3-3; II d 1-2-1, p 2-2-2, r 2-2-2; III d 1-2-1, p 1-2-2, r 2-2-2; IV d 2-2-1, p 0-1-2, r 0-1-3; tibiae: I p 2-3-2, v 3-3-4, r 2-2-2; II p 2-2-2, v 3-4-3, r 1-1-2; III d 1-0-1, p 0-2-2, v 1-1-4, r 0-2-1; IV missing; metatarsus: I p 3-1-2, v 1-1-1, r 2-2-2; II d 0-1-2, p 1-2-2, v 0-1-2, r 1-1-0; III p 1-1-2, v 2-3-2, r 2-2-1; IV missing. Palp (Figs 5-10): cymbium slender, median apophysis slender and spine-shaped with serrated tip, embolus broad with twisted, membranous flange and slit-like opening, membranous spermophor as depicted in Figs 8-10, m29 and m30 originating in tibia. The 3D reconstruction revealed that the spermophor fills most of the subtegulum and is flattened and thin within the embolus (Video 1). Abdomen missing.

Appendages measurements:

Natural history.

The webs of Thaida chepu are very similar to those described for Thaida peculiaris Karsch 1880 and Austrochilusforsteri Grismado, Lopardo & Platnick, 2003 by Lopardo et al. (2004) (Fig. 2).