Xenoctenus unguiculatus Mello-Leitao 1938
Creators: name: Faustino-Magalhaes, Mayara D.
name: Piacentini, Luis N.
name: Santos, Adalberto J.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Xenoctenidae
Xenoctenus
Xenoctenus unguiculatus

description: Xenoctenus unguiculatus Mello-Leitão, 1938
Figs 1F, 2–6, 14, 15
Xenoctenus unguiculatus Mello-Leit „o, 1938: 101 (immature holotype from Argentina, San Luis, Desaguadero [33°24’3.05” S, 67°9’14.94” W, alt. 461 m], Bruch coll., deposited in MLP 14093, examined.
Xenoctenus marmoratus Mello-Leit „o, 1941: 160, pl. 8, fig. 38 (immature holotype from Argentina, Tucumán, Bañado [26°25’19.71” S, 65°57’44.99” W, alt. 1721 m], Birabén coll., Feb.1939, deposited in MLP 14835, examined. Prosen 1951: 57, figs 1–3; Lehtinen 1967: 457, fig. 407; Carcavallo & Martínez 1967: 78, figs 2, 6. Syn. Nov.)
Xenoctenus sp. — Ramírez 2014 (voucher specimens MACN-Ar 45040 and MACN-Ar 45039, examined).
Diagnosis. Males of X. unguiculatus are similar to X. kaatinga in the elongated, longer than wide cymbium and copulatory bulb (Figs 5, 11A–C), but can be distinguished by the thinner median apophysis and the acuminated apex of the retrolateral tegular projection (RTP, Figs 4B, 5B). Males of X. unguiculatus differ from X. vittatus by the presence of the RTA similar to a macrosetae and from X. kaatinga by the RTA with the pointed tip (Figs 5B, C). Females of X. unguiculatus resemble those of X. kaatinga in the elongated epigynum (Figs 6A, C, 12C), but can be differentiated by the presence of posterior, medially directed teeth on the lateral lobes extension (LLE, Fig. 6A, C).
Remarks. The holotype of X.unguiculatus are a small juvenile, too old and fragmented to allow the identification of the species (Fig. 2). We identified this species based on specimens collected throughout northern and northwestern Argentina, including samples taken around 60 km from the type-locality (Fig. 15). The holotype of X. marmoratus is also a juvenile, though at least with partially preserved color pattern (Fig. 3). We proposed the synonymy of this species with X. unguiculatus because the former type-locality is located within the distribution range of the latter (Fig. 15). Our decision is further supported by the absence of any Xenoctenus species in collection samples collected near the type locality, except for the one described and illustrated herein.
Description. MALE FROM PARQUE NACIONAL SIERRA DE LAS QUIJADAS, SAN LUIS, ARGENTINA (MACN-AR 45013; FIG. 4). Carapace light brown, with dark brown irregular bands at its margin, dark brown radial lines, enhanced by dark setae, and a median darker line (Fig. 4D). Paler area of the carapace covered with white setae, denser on the cephalic area and the border of the carapace (Fig. 4D). Opisthosoma dorsally light brown with irregular darker areas and patches of white setae dorsally (Fig. 4D). Venter light brown. Eight eyes in two recurved rows surrounded by a dark line, except for the smaller and pale ALE (Figs 2 B, 3 B, 4D). Chelicerae reddish brown. Labium, endites and sternum light brown. Legs yellowish, with darker dorsal markings on femora and patellae (Fig. 4D), with dense scopula on the tarsus and less dense on metatarsus and the apex of tibia. Pedipalps light brown, tibia with ventral macrosetae, with a small, inconspicuous RTA, which is covered by short, white setae (Fig. 5 B, C). Cymbium covered by setae and with an apical thick scopula (Fig. 5). Copulatory bulb sclerotized, dark-brown to black, longer than wide (Figs 4A– C, 5). Conductor membranous and translucent (Fig. 4 B, 5B). Embolus flat, with a basal locking lobe (ELL) connected to the subtegular locking lobe (StLL, Fig. 4B). Retrolateral tegular projection (RTP) thick and curved apically (Figs 4 B, 5B), followed by an additional retrolateral projection (Fig. 4 C, 5C). Tegular distal division (TDD) triangular (Figs 4 B, 5B) Median apophysis longitudinally oriented and flat (Figs 4 B, C, 5 B, C). Total length 17.82. Carapace length 8.78, width 7.18. Eye diameters: AME 0.30, PME 0.40, ALE 0.25, PLE 0.35. Femur of leg I: 11.97, II 11.70, III 10.77, IV 13.03.
FEMALE FROM PARQUE NACIONAL SIERRA DE LAS QUIJADAS, SAN LUIS, ARGENTINA (MACN-AR 45013; FIG. 6 C, D). Coloration as in male (Fig. 1F). Epigynum with lateral lobes very sclerotized, dark brown, median field membranous (Fig. 6A, C). Internal genitalia sclerotized, dark brown. Primary spermathecae long and secondary spermathecae shorter and rounded, located anteriorly (Fig. 6B, D). Total length 18.49. Carapace length 9.18, width 7.58. Eye diameters: AME 0.37, PME 0.38, ALE 0.30, PLE 0.42. Femur of leg I 9.31, II 8.78, III 8.78, IV 11.04.
Variation. Female body size exhibits significant variation, even among specimens collected from the same locality. Female epigyna vary in orientation of the lateral lobes, which can be near straight (Fig. 6A) to angled (Fig. 6C). Although males are also variable in body size, the palp does not show any significant variation. Total body length: females, 16.63–22.08 (n=10); males, 12.10–23.14 (n=24).
Distribution. Southern Brazil and Argentina, in Buenos Aires and the central and northern zones of western Argentina, in the Chaco, Monte and Pampean biogeographic provinces (sensu Morrone et al. 2022) (Fig. 15).
Additional material examined. BRAZIL. Rio Grande do Sul: Porto Alegre, P. Buck coll., VIII/1962, 1 ♀ (IBSP 1787). ARGENTINA. Buenos Aires: L. Coronel coll., VII/1988, 1 ♁ (IBSP 5022). Salta: Guachipas, Magnesita, La Salamanca, Valles Calchaquíes, 7 km de Alemanía [25°37’27.11”S, 65°36’46.49”W, 1184 m], Ramírez, M. J. & Goloboff, P.A., 17/VII/1995, 1 ♀ (MACN-Ar 17966). Formosa: Bermejo, Reserva Natural Formosa, Seccional RÍo Teuco [24°18’42.20”S, 61°48’44.50”W, 178 m], Izquierdo, M. A., 27/VI-05/VII/2010, 1 ♁ (MACN-Ar 27353). Chaco: General Ģemes, El Pintado [24°41’21.95”S, 61°25’37.28”W, 157 m], Bachmann, A., XI/1959, 1 ♁ (MACN-Ar 5444); Paraje La ArmonÍa [25°10’52.72”S, 61° 5’42.89”W, 138 m], Damer, L., 12/X/2013, 1 ♀ (MACN-Ar 33414). Catamarca: La Paz, Recreo [29°16’34.6’’S, 65°3’51.4’’W], 4/XII/1956, 1 ♁ (MACNAr 17983); Andalgalá, Andalgalá [27°35’30.88”S, 66°19’10.61”W, 1041 m], Enders, 19/X/1972, 2 ♁ (MACNAr 18002); Villavil, Frank A. Enders coll., 30/XII/1973, 3 ♁ 1 ♀ (NMNH); ditto, 30/XII/1974, 3 ♁ 1 ♀ 1 imm. (NMNH); 30/XII/1973, 4 ♀ 1 imm. (NMNH); 5–25/XII – I/1973 –1974, 3 ♀ 1 imm. (NMNH); 2/XII/1972, 2 ♀ 1 imm. (NMNH); 29/X/1972, 1 ♁ (NMNH); 1 ♁ (NMNH); 1 ♀ 1 imm. (NMNH); 29/X/1972, 2 ♀ 1 imm. (NMNH); 30/XII/1973, 1 ♀ 1 imm. (NMNH); 27/I/1972, 1 ♀ 1 imm. (NMNH); 23/XI/1972, 1 ♁ (NMNH); 5/I/1974, 1 ♁ (NMNH); 11/II/1974, 1 ♁ 4 imm. (NMNH); 30/XII/1973, 2 ♁ 2 ♀ (NMNH); 23/XI/1972, 2 ♀ 1 imm. (NMNH); 25/I/1974, 1 ♀ (NMNH – USNMENT 01458297). La Rioja: without exact locality, Viana, J. M., XI/1959, 1 ♁ (MACN-Ar 17975); Independencia, Patquía, Guayapa [30°2’41.34”S, 66°52’52.54”W, 434 m], Maury, E. A., III/1965, 1 ♁ (MACN-Ar 17970); Galiano, M. E., X/1963, 1 ♁ (MACN-Ar 17969); Capital, Dique Los Sauces [29°23’5.75”S, 66°58’47.90”W, 850 m], Maury, E., 7-8/X/1965, 1 ♀ 3 imm. (MACN-Ar 45040). Santiago del Estero: Guasayan, Santa Catalina [28° 7’18.31”S, 64°46’51.70”W, 436 m], Galiano, M. E., 26/X/1963, 1 ♁, 1 ♀ (MACN-Ar 45039); Moreno, Mercedes, 10 km E de Amamá [27°12’26.22”S, 62°56’7.47”W, 161 m], Vezzani, D., VII/1995, 1 ♀ 17 imm. (MACN-Ar 17971); Weisburd [27°19’22.55”S, 62°35’9.24”W, 153 m], 22/IX/1947, 1 ♀ (MACN-Ar 17997); Robles, Fernández [27°55’16.71”S, 63°53’30.37”W, 154 m], Salguero, J., IX/1960, 1 ♀ 1 imm. (MACN-Ar 17972); Choya, [28°29’42.56”S, 64°51’33.78”W, 384 m], Salguero, J., 12/X/1961, 1 ♁ 1 imm. (MACNAr 17982); Salguero, J., 05/V/1962, 6 ♁ 1 ♀ 4 imm. (MACN-Ar 18001); 1 ♀ (MACN-Ar 34165); Villa La Punta [28°22’12.76”S, 64°47’34.53”W, 389 m], Donado, O., 18/II/1981, 1 ♁ (MACN-Ar 17974). San Juan: Sierra pie de palo, vega, 25 km (por aire) W de El Bosque [LNP-loc-34] [31°22’50.27”S, 68°8’19.82”W, 996 m], Piacentini, L.N., Ojanguren, A. & Mattoni, C., 20/XII/2014, 1 ♀ (MACN-Ar 34662); Valle Fértil, Reserva Natural Provincial Valle Fértil, (JPA-Loc-03) [30°41’10.99”S, 67°30’15.97”W, 952 m], Pardó, J., 12/III/2014, 1 ♁ (MACN-Ar 35606); Caucete, Al costado de la Ruta Provincial Nº141, 25 km (por aire) NW de Caucete [LNP-loc-35] [31°45’30.71”S, 68° 3’6.01”W, 687 m], Piacentini, L.N., Ojanguren, A. & Mattoni, C., 20/XII/2014, 1 ♀ (MACN-Ar 35624). San Luis: Parque Nacional Sierra de las Quijadas [32°29’37.4’’S, 66°59’33.5’’W, 765 m], C. Grismado et al. coll., 7/ XI/2013, 1 ♀ (MACN-Ar 31091); Parque Nacional Sierra de las Quijadas, alrededores del área de servicios (CJGLoc-03a) [32°28’8.40”S, 66°57’39.06”W, 710 m], C.J. Grismado et al. coll., 04/XI/2013, 1 ♀ (MACN-Ar 33447); Parque Nacional Sierra de las Quijadas, al costado de la ruta, camping viejo [32°29’45.06”S, 67° 0’11.67”W, 817 m], A. Ojanguren et al. coll., 01/II/2022, 1 ♁ 1 ♀ (MACN-Ar 45013); Parque Nacional Sierra de las Quijadas, al costado de la ruta, camino al mirador [32°29’43.95”S 66°59’41.30”O, 794 m], A Ojanguren et al. coll., 01/II/2022 1 ♁ (MACN-Ar 45277); La Capital, San Gerónimo [33° 8’18.76”S, 66°31’20.13”W, 541 m], II/1977, 1 ♀ (MACNAr 18003). Mendoza: Lavalle, Reserva Natural y Cultural Bosques Telteca, 100 m a la redonda del puesto El Pichón (RBT-Loc-11) [32°22’32.11”S, 68° 2’46.78”W, 554 m], Botero Trujillo, R. & Carbajal, A. L., 14/XI/2015, 1 ♁ (MACN-Ar 35619); 3 imm. (MACN-Ar 38991); 1 ♁ (MACN-Ar 40932). Córdoba: Ischilin, Salinas Grandes [29°49’23.88”S, 64°47’34.17”W, 180 m], Equipo LABRE coll., 24/XI/2016 1 ♁ (LABRE 319); Pocho, Chancaní [31°24’59.78”S, 65°26’59.55”W 383 m] Izquierdo, M., pit fall traps, 15/XI/2005 1 ♁ (LABRE 246); 1 ♁ (LABRE 244); 1 ♁ (LABRE 245). La Pampa: Curacó, Gobernador Duval [38°43’33.95”S, 66°26’19.86”W, 222m], M. Izquierdo & H. Iuri coll., 19/01/2018, 1 ♁ (LABRE 350).
description: Published as part of Faustino-Magalhaes, Mayara D., Piacentini, Luis N. & Santos, Adalberto J., 2024, The desert wolf-spider genus Xenoctenus: two endemic species from the Brazilian Caatinga, and a redescription of the type-species, X. unguiculatus (Araneae: Xenoctenidae), pp. 517-539 in Zootaxa 5399 (5) on page 520, DOI: 10.11646/zootaxa.5399.5.3, http://zenodo.org/record/10517346