3.3. 5. Euathlus tenebrarum Ferretti, 2015

Figures 16, 17, 18, Table 7

Type material.

Holotype: ARGENTINA • 1 ♂; Neuquén, Huiliches Department, next to Curruhué Chico lake; 39.9078°S 71.3328°W; 1042 m a. s. l.; 28 Oct. 2011; L. Schwerdt leg.; MACN -Ar 32687 .

Other material.

ARGENTINA • 4 ♀♀; Neuquén, Huiliches Department, Junín de los Andes; 39.9461°S 71.0730°W; 27 Feb. 1968; Maury and N. Mullet leg.; MACN -Ar 45254, 47712, 47781, 47806 . • 1 ♂; same data as preceding; MACN -Ar 46231 .

Amended diagnosis.

Male differs from the other Euathlus species by a tibial apophysis with slightly developed branches almost of equal sizes (Fig. 16 A – C) and by the strong curvature of the embolus, reaching almost 90 ° between embolus and tegulum (Fig. 16 D – H). The PB has three strong spines, two internal ones, one of which is located more basally and the other subapical, and one external spine. Females differ from other congeners by the shape of the spermathecae, consisting of two high sub-quadrate seminal receptacles with upper margin slightly mounded; each with a lateral wide oval chamber connected with a wide duct (Fig. 17).

Description female.

Female (MACN -Ar 47712). — Coloration (in alcohol): reddish brown, two yellowish lines on femora, patella, and tibia of palps and legs I-IV. Total length 25.52. — Prosoma: Carapace length 10.60, width 9.46 (Fig. 16 A). Anterior eye row procurved, posterior one recurved. Eyes sizes and interdistances: AME 0.16, ALE 0.31, PME 0.12, PLE 0.39, AME - AME 0.42, AME - ALE 0.16, PME - PME 0.74, PME - PLE 0.08, ALE - PLE 0.23, OQ length 1.19, width 1.60. Clypeus absent. Fovea transverse, slightly procurved, width 1.55. Labium length 1.46, width 1.73 with 91 cuspules. Sternum length 4.87, width 4.56 (Fig. 16 B). Chelicerae with 6 well-developed teeth on promargin of furrow and 7 teeth on the proximal area on retromargin. — Appendages: Tarsi I – IV densely scopulated and entire. Metatarsi I fully scopulated, II 2 / 3 scopulated, III 1 / 2 scopulated, IV 1 / 4 apically scopulated. Leg and palpal segments lengths in Table 7. Spination: Femora, patellae, and tarsi of palps and legs I – IV, 0. Tibiae: palp 0-0 - 0 - 2 (ap) V, 1-0 - 1 - 1 (ap) P; I 0-0 - 1 - 2 (ap) V, 0-0 - 0 - 1 (ap) P; II 0-1 - 0 - 3 (ap) V; III 0-1 - 0 - 3 (ap) V, 0-0 - 1 - 0 P; IV 0-1 - 0 - 0 V, 0-1 - 0 - 1 (ap) P, 0-1 - 1 - 1 (ap) R. Metatarsi: I 1-0 - 0 - 1 (ap) V; II 0-1 - 0 - 0 V; III 1-2 - 0 - 3 (ap) V, 0-1 - 0 - 1 P, 0-0 - 0 - 1 R; IV 1-2 - 1 - 3 (ap) V, 0-1 - 0 - 1 P, 1-1 - 3 - 1 R. — Opisthosoma: Types III and IV urticating setae present. Four spinnerets, PMS 0.92 long and PLS three segmented, basal segment 1.94 long, medial segment 1.26 long and apical segment 1.12 long. — Genital organs: Spermatheca consisting of two high seminal receptacles, sub-quadrate, with upper margin not straight, with a few small mounds; each with a lateral wide oval chamber connected with a wide duct (Fig. 16 D).

Remarks.

The female specimen previously designated as a paratype of Euathlus tenebrarum (MACN -Ar 32688) is herein reassigned to Euathlus basalticus sp. nov. This decision is based on a comparative analysis of additional specimens deposited in the MACN collection, including three females (MACN -Ar 47712, 47806, 47781) and one male (MACN -Ar 46231) (Fig. 17) from Junín de los Andes. The male matches with the morphology described for E. tenebrarum by Ferretti (2015), while the females show clear morphological differences. Furthermore, during a field campaign conducted in November 2023, we surveyed localities near the record of the aforementioned paratype female collecting one adult male (UNS M 1122), whose morphology differs considerably from that of E. tenebrarum and is consistent with the diagnosis of Euathlus basalticus sp. nov.

Distribution.

Previously known from the Huiliches Department, Neuquén province, Argentina. The species has been recorded near Curruhué Chico Lake (type locality) (Ferretti 2015). From this work, recorded in Junín de los Andes, Neuquén province (Fig. 18).