Mediothele nahuelbuta, T, Duniesky Rios & Goloboff, Pablo A., 2012

T, Duniesky Rios & Goloboff, Pablo A., 2012, New species of Chilean Hexathelidae (Araneae, Mygalomorphae), Zootaxa 3422, pp. 32-51 : 45-47

Mediothele nahuelbuta sp. nov.

Figures 47–52

Type. Female Holotype (6811 MNHN) from Parque Nacional Nahuelbuta [37°47'47"S 72°59'43"W], Malleco , Chile. 13 Feb 1992 (M. Ramírez–N. Platnick–P. Goloboff).

Etymology. The specific name is a noun in apposition taken from the type locality.

Diagnosis. Females of M. nahuelbuta can be distinguished from those of M. lagos by their wider labium and shorter spermathecae, and from those of all the other congeners by the spination of leg I and the narrower sternum. They also differ from those of M. minima by their larger size, from those of M. australis by the shorter spermathecae, and from M. linares by their wider cephalothorax.

Female (Holotype). Total body length 8.52. Cephalothorax wide, slightly arched, length 3.60, width 2.76. Cephalic region, length 2.28, width 2.28. ALE largest, anterior ocular row straight, posterior recurved, with 8 thick setae before, and 6 thick setae behind, ocular group. Fovea straight; dorsal midline of cephalothorax with series of 7 setae reaching fovea. Chelicerae robust, with rastellum-like thick setae on anterior edge, with 7 large promarginal teeth and 8 denticles in basal part of fang furrow. Palpal coxae with 4–7 cuspules. Labium length 0.32, width 0.68, without cuspules. Sternum rounded, 1.96 long, 1.76 wide, with three pairs of marginal sigilla. Opisthosoma length 4.08, light brown with lighter transverse bands forming chevron interrupted in center. PLS with basal: medial: apical articles of lengths 0.64: 0.40: 0.44; PMS monoarticulate, length 0.48; ALS biarticulate, basal article 0.20 long, apical article very small, 0.08 long, with 6–7 spigots. Tarsi I 0.84 long, 0.32 wide, metatarsi I length 1.32. C haetotaxy: Patellae, tibiae and metatarsi III–IV with many small spine-like setae from P edge to dorsal midline. Femora: I, 1–1–1–1–1–1 d; II, 1–1–1 d (1: 2 b); III, 0; IV, 1–1–1–1–1–1 d; palp, 1 p a sup, 1 p a inf. Patellae: I, 2 v a; II, 0; III, 0–1–2 P; IV, 0; palp, 1 P. Tibiae: I, 1–1– 1 V POST; II, 1–2– 1 V POST; III, 1–1–2 P, 1 D B, 1 R A; IV, 1–1– 1 V ANT (thin); palp, 1–0–2– 2 V ANT, 2–0–1– 2 V POST. Metatarsi: I, 0–1–1– 1 V ANT, 1–1– 1 V POST, 1 V B, with apical preening comb (of 2 bristles); II, 1 V A ANT, 1–1– 2 V POST, with apical preening comb (of 2 bristles); III, 0–1–1 R SUP, 1–1–1 P SUP, 1 V A ANT, 1 V A, 1 V A POST, with 3 apical preening combs (of 5–2–3 bristles); IV, 1–1–1–0–1 P, 0–1–0–1 R SUP, 1–0–1– 1 V ANT, 1 V (thin), 2 V A POST, with 2 apical preening combs (of 7–5 bristles). Tarsi: I, 1–1–1–0 V POST; II, 1–1–0 V; III–IV,0; palp, 1–1–1–1–1 P INF, 1–1–0–1–1 R INF, 1 V M. Trichobothria: tarsi I–III with 4, IV with 5; metatarsi I–III with 5, IV with 7; all tibiae with two rows of 4.

Variation in other females. Patellae: II, 1 p a; III, 1–1– 2 P. Tibiae: II, 1–1– 1 V POST; III, 1 D B, 0–1–1 R SUP, 1–0–1 P SUP, 0–1–1 P INF. Metatarsi: I, 0–1–1–1– 1 V ANT, 0–1–1–1– 2 V POST, 1–1–1– 1 V (thin); II, 1–1– 1– 2 V POST, 1 V ANT, 0–1–0–1 P SUP, with 2 apical preening comb (of 2–3 bristles); III, 0–1–1– 1 V ANT, 1 V A POST, 0–1–1–1 P SUP, 0–1–0–1 R SUP, with 3 apical preening combs (of 4–3–4 bristles); IV, 0–1–0–1 R SUP, 1– 1–1–0–1 P INF, 0–1–1– 1 V ANT, 1 V A POST, with 2 apical preening combs (of 6–3 bristles). Tarsi: I, 2–1–1–0 R INF, 1 P M INF; II, 1–1–1 P INF (the two basal ones thinner). Trichobothria: Tarsi I, II, and IV with 4, III with 3; metatarsi I, II with 5, III with 4, IV with 7; tibiae I–IV with two rows of 4.

Male. Unknown.

Distribución. Known only from Region IX (de la Araucanía), province of Malleco .

Other specimens examined. Chile: Región IX (de la Araucanía): Malleco: Monumento Natural Contulmo [38° 1'41"S 73°12'10"W], 12 Jan 1989 (M. Ramírez – Maury) 5 Ƥ, 1 juv ( MACN). 11–12 Feb 1992 (P. Goloboff – N. Platnick – M. Ramírez) 4 Ƥ ( MACN) 1 Ƥ ( AMNH), 2 juv., Parque Nacional Nahuelbuta [37°47'47"S 72°59'43"W], 13 Feb 1992 (M. Ramírez – N. Platnick – P. Goloboff) 2 Ƥ ( MACN).

Observations. Specimens from Contulmo present small differences from other specimens (the cephalothorax is shorter, with the fovea procurved, and the spermathecae are slightly different, see Fig. 52 , right). They share the peculiar spination of the anterior tarsi and metatarsi. When more adults are known, the specimens from Contulmo may prove to belong to a different species.

Figures

FIGURES 47 – 52. Mediothele nauhelbuta sp. nov., female. 44 – 48. Right leg I, retrolateral and ventral views. 49. Sternum and maxillae. 50 – 51. Spinnerets. 52. Spermathecae, holotype (left) and variation (right – Malleco: Monumento Natural Contulmo, 12 Jan 1989).