Euathlus tenebrarum Ferretti, 2015

Allegue, Maite, Peralta-Seen, Nicolás & Ferretti, Nelson, 2025, Integrative systematics of the tarantulas Euathlus Ausserer, 1875 from Argentina: cladistics, molecular phylogeny and new species (Araneae: Theraphosidae), Arthropod Systematics & Phylogeny 83, pp. 713-736 : 713-736

publication ID	https://doi.org/10.3897/asp.83.e171040
publication LSID	lsid:zoobank.org:pub:90DE5EC9-FEFB-4E43-B496-FDD96A39B50C
DOI	https://doi.org/10.5281/zenodo.17866508
persistent identifier	https://treatment.plazi.org/id/00FBD712-3979-53D8-88B9-0F43108BE2A9
treatment provided by	Arthropod Systematics & Phylogeny by Pensoft
scientific name	Euathlus tenebrarum Ferretti, 2015
status

Treatment

3.3. 5. Euathlus tenebrarum Ferretti, 2015 View in CoL

Figures 16 View Figure 16 , 17 View Figure 17 , 18 View Figure 18 , Table 7 View 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 GoogleMaps .

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 GoogleMaps . • 1 ♂; same data as preceding; MACN -Ar 46231 GoogleMaps .

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 View Figure 16 ) and by the strong curvature of the embolus, reaching almost 90 ° between embolus and tegulum (Fig. 16 D – H View Figure 16 ). 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 View Figure 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 View Figure 16 ). 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 View Figure 16 ). 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 View 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 View Figure 16 ).

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 View Figure 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 View Figure 18 ).