Figures 8–11
Type material. Holotype: Female from General Roca (39 o 02’S, 67 o 31’W), Province of Río Negro, Argentina, October 1963, Bachmann coll., deposited in MACN. Paratypes: Two females from the same locality as the holotype, deposited in MACN. Female from the same locality, deposited in IBSP 79531. Female from Los Altares (43 o 51’S, 68 o 48’W), Province of Chubut, Argentina, 3–5.XI.1990, L.E. Peña coll., deposited in AMNH. Female from Valle de las Ruinas (43 o 51’S, 68 o 15’W), Ruta Nacional 25, Province of Chubut, Argentina, 31.IX.1982, M.J. Ramírez coll., deposited in MACN.
Etymology. The specific name refers to Kóoch, a deity from the mythology of the Tehuelche Indians, the original inhabitants of the Argentinean Patagonia. According to the creation myths of this people, Kóoch created the primitive ocean with his tears after many ages of crying of loneliness in the dark. The name is to be treated as a noun in apposition.
Diagnosis. Platoecobius kooch can be recognized by the anterior pit of the epigynum half-moon shaped and located close to the copulatory openings (Figs. 9, 11). In P. floridanus the anterior pit is deeply incised, Vshaped and is located distant from the copulatory openings (Shear 1970: figs. 46, 47; Craig et al. 2005: fig. 43.8). The internal genitalia (Fig. 10) differ by the absence of the strongly sclerotised basal quarter of copulatory ducts, which is present in P. floridanus (Shear 1970: fig. 47) and is usually visible through translucent epigynal integument (Shear 1970: fig. 46; Craig et al. 2005: fig. 43.8). Additionally, P. kooch can be recognised by the retrolaterally bent fertilisation ducts and almost straight copulatory ducts (respectively straight and curved in P. floridanus, Shear 1970: fig. 47).
Description. Male, Unknown.
Female (holotype). Carapace dark grey, darker on the margins. Ocular mound with a posterior bird-shaped dark spot (Fig. 8). All eyes white, except anterior medians. Clypeus, chelicerae, labium, endites and sternum brownish. Coxae and trochanters cream-coloured, dark grey laterally. Femora cream-coloured, with a median and an apical dark rings. Patellae, tibiae, and metatarsi cream-coloured, dark grey in the distal half. Tarsi cream-coloured. Pedipalp cream-coloured, with all segments except tarsus darker in the distal half. Abdomen dorsally black with lateral, sinuous white stripes from the anterior margin to posterior second third. Posterior portion of abdominal dorsum white. Paler areas of abdomen with a few white guanine spots. Sides black, venter cream-coloured. Spinnerets grey, darker on retrolateral sides. Cribellum divided, calamistrum occupying the basal two-thirds of the length of metatarsus IV. Epigynum very simple, with only the transverse septum delimiting copulatory openings and anterior pit (Fig. 11) and the fertilisation duct sclerotised capsules visible by transparency through the cuticle (Fig. 9). Internal genitalia with spermathecae collapsed, probably due to manipulation or dehydration by ethanol preservation. Copulatory and fertilisation ducts widely attached to spermathecal median wall, CD clearly less sclerotised than FD. Sclerotised capsule with a wide and short dorsal duct, possibly connected to uterus externus (Fig. 10). Total length 2.8. Carapace 0.67 long, 0.97 wide. Tibia I length 0.57, II 0.57, III 0.53, IV 0.6. Abdomen 1.9 long, 1.4 wide.
Variation. Total length 2.27–2.93; carapace width 0.97–1.07 (N=5). Some specimens have the abdomen almost completely black, with a pair of lateral and a posterior cream-coloured spots (Fig. 8).
Distribution. Southern Argentina.
Natural history. The holotype was found under a stone (M.J. Ramírez, personal communication).