Chileotrecha argentinensis Iuri new species

Figs. 3–6, 7, 8, 11–12, 17–28; Table 1

Type material. Holotype ♂ MACN (31210): Argentina, San Luis, Sierra de las Quijadas National Park, 705 m asl, [32,46900ºS 66,96085ºW]. 3–7-XI-2013. H. A. Iuri, A. A. Ojanguren-Affilastro, C. J. Grismado, C. Mattoni and R. Botero-Trujillo coll.

Paratypes: 4 ♂ MACN (31211 to 31214): Same data as the holotype; 2 ♀ MACN (31215 and 31216): Same data as the holotype; 1 immature MACN (31217): Same data as the holotype; Other examined material: 1 ♂ MACN (31218): Argentina, Catamarca, Andalgalá. 27-II-1972. F. Enders coll.; 1 ♀ MACN (31219). Argentina, San Juan, Astica. 13-IV-1979. A. Roig-Alsina coll.; 1 immature MACN (31220). Argentina, San Juan, 50 km N of Marayes. 12-IV-1979. A. Roig coll.

Etymology. The name of the species refers to Argentina, where it was collected. This is the first record of genus Chileotrecha for this country.

Diagnosis. Males of C. argentinensis n. sp. can be separated from males of C. atacamensis because the apex of flagellum of C. argentinensis n. sp. bears few spicules and is placed over a furrow at the fixed finger tip (Fig. 4), whereas in C. atacamensis it bears several spicules and is placed above the fixed finger tip (Fig. 2). Additionally in C. argentinensis n. sp. the ventral border of the flagellum is almost straight and the attachment ring is located between the principal and first ectal fondal teeth (Fig. 4), whereas in C. atacamensis the ventral border of the flagellum is concave and its attachment ring is placed at the level of the second ectal fondal tooth (Fig. 2). In C. argentinensis n. sp. the fixed finger tip is less inclined and the anterior teeth less prominent than in C. atacamensis (Figs. 1 and 3). Chileotrecha argentinensis n. sp. presents a yellowish pedipalp tarsus (Fig. 8), whereas in C. atacamensis it is dark brown. In C. argentinensis n. sp., the posterior edges of lateral lobes of female genital plate, are more convex than in the female specimens from Chile that we have studied (not assigned to any species) (Fig. 6).

Description. Male Holotype. Measurements in mm in Table 1.

Color in 96 % ethanol. Prosoma: Propeltidium dark brown with central portion pale brown. Lateral lobes dark brown. Ocular tubercle black. Insertion of setae yellowish. Para-, meso- and metapeltidium dark brown, insertion of setae yellowish.

Chelicerae: dark brown with three longitudinal oval areas pale brown. Insertion of setae yellowish.

Pedipalps: Femur and tibia brown with apical portion pale yellowish. Metatarsus dark brown. Tarsus pale yellowish. Insertion of setae pale yellowish.

Legs: Legs I, II and III; coxae and trochanter pale yellowish. Femur, tibia and metatarsus brown with apical portion pale yellowish. Tarsus yellowish. Leg IV; with a similar color pattern, but the brown portion is darker.

Malleoli: Brown with external margin darker.

Opisthosoma: Tergites dark brown with insertion of setae yellowish. Pleurites dark grey in the dorsal half and yellowish in ventral half. Sternites yellowish.

Morphology and Chaetotaxy: Prosoma: Propeltidium wider than long with some short spiniform blunt setae, separated from lateral lobes by dorsal grooves. Peltidium narrow, with a transverse row of different-sized spiniform blunt and bifurcated setae. Parapeltidium smooth. Meso and metapeltidium wider than long, with spiniform blunt and bifurcated setae.

Chelicerae (Figs. 3, 4, 23): Ectal and dorsal surfaces covered by spiniform blunt and bifurcated setae. Mesal surface covered by small bristles, with two rows of plumose setae behind the teeth line and one posterior row of blunt setae. Stridulatory apparatus with eight parallel ridges (Fig. 23). Movable finger with one row of plumose setae, and two rows of blunt setae. Dentition: Movable finger with one anterior (I), one intermediate (II), and one principal tooth (III) arranged in increasing size: II, I and III. Fixer finger with three anterior (I–III), one intermediate (IV), and one principal tooth (V), arranged in increasing size IV=II, I, III=V; four ectal fondal teeth arranged in increasing size II=IV, I=III, and four mesal fondal teeth arranged in increasing size II, IV, III, I with I and II separated from III and IV by a diastema (similar to mesal fondal teeth arrangement in fig. 2). Fixed finger tip slightly curved downward (Fig. 3).

Flagellum (Figs. 4, 23, 24): A thin translucent drop-shaped membrane, with nearly straight ventral border. The folded edge presents several rows of spicules that become more prominent in the apical area. The inner surface is covered by several spicules (Fig. 24). The attachment ring of the flagellum is located at the level between principal and first ectal fondal teeth (Fig. 4).

Pedipalps (Figs. 11, 12, 28): All segments coated with several small truncated tip setae with pore (Fig. 11), some blunt setae of different sizes, and small ventral spines. Metatarsus with a few clubbed setae (Fig. 12). Tarsus short, with some clubbed setae, bifurcated setae and dorsal pores (Fig. 28). The clubbed setae are twice as long as the truncate setae with pore. The blunt setae present different sizes, but are always equal or longer than clubbed setae. Tibia with five paired short spines and metatarsus with six paired short spines; the basal pair is the weakest in both segments.

Legs: Leg I (Figs. 17–20): Without claws and spines, covered with small blunt setae; metatarsus with some clubbed setae; tarsus with some clubbed and some bifurcated setae (Fig. 19), and with an apical structure (Fig. 20) that could be a vestigial remnant of the claw. Legs II, III and IV covered with some robust bifurcated setae, and some blunt setae with different sizes. The trochanters possess robust dorsal spiniform setae. Legs II and III: Tibia with two apical ventral spines; metatarsus with 1.1.1 retrolaterodorsal spines, 1.1 retrolateral spines intercalated with the retro-latero-dorsal being 1.(1).1.(1).1, and 1.1.2 ventral spines; tarsus bi-segmented with 1.2.2/2.2 ventral spines. Leg IV (Figs. 21–22): Tibia with 1.1.2 ventral spines; metatarsus with 1.1.1.2 ventral spines; tarsus bisegmented with pseudo segmentation on basal segment (Fig. 22), and 2.2.2-2/2.2 ventral spines.

Opisthosoma: Tergites with some spiniform blunt and bifurcated setae. Sternites (Figs. 25–27) with several bifurcated and a few tapered setae (Fig. 27). Two pairs of microsetae (Fig. 26) are placed in the posterior margin of genital plate (Figs. 25, 26) and in the posterior margin of spiracular sternites I and II, whereas in postspiracular sternite I there is only one microseta on each side.

Female paratypes: Measurements in mm in Table 1.

Similar to male, but more glabrous, especially on the pedipalp. Prosoma and dorsal surface of trochanters with some spiniform bifurcated setae. Propeltidium notably wider than long. The spines of pedipalps are longer than in males. Chelicerae with a dorsal hump on the fixed finger (Fig. 5). Genital plate as in Figure 6.

Distribution: Chileotrecha argentinensis n. sp. occurs in central-western Argentina (Fig. 7), in areas of Monte and ecotonal zones of Monte and arid Chaco; in an altitude range from 700 to 1000 m asl. Most of the studied specimens were collected in Sierra de las Quijadas National Park, in a rocky area at the base of some low hills in the park main entrance. The environment corresponds to the Argentine Monte de Llanuras y Mesetas ecoregion (Burkart et al., 1999). The climate in the area is warm and dry, with large daily thermal range and low rainfall (80–300 mm annually). The predominant vegetation is high shrub steppe (Pol et al, 2006).