Lobizon humilis Mello-Leitao 1944, comb.nov.
Creators: name: Piacentini, Luis N.
name: Grismado, Cristian J.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Lycosidae
Lobizon
Lobizon humilis

description: Lobizon humilis (Mello-Leitão, 1944) comb.nov.
(Figs 6–8, 11–12, 33–38, 79, 81, 85)
Alopecosa humilis Mello-Leitão 1944: 338 –339 (fig. 28); male holotype from Argentina, Buenos Aires, Tigre, Guayracá, Prosen coll. in MLP 16015, examined.
Alopecosa unguiculata Mello-Leitão 1944: 339 –341 (fig. 29); female holotype from Argentina, Buenos Aires, Tigre, Guayracá, Prosen coll., deposited in MLP number 16020, examined. New synonymy.
Other material examined. ARGENTINA: Corrientes: Parque Nacional Mburucuyá, 27°58’– 26°05”S, 57°59’– 58°08’W, specimens examined by Rubio et al. (2008, under Alopecosa), 1 male, 9 female. Santa Fe: Las Gamas, 20 km W Vera, ca. 29°25’S, 60°21’W, 27.X.1994, Ramírez M. & Faivovich J., 1 female, 1 immature (MACN-Ar 16275); same data, 1 male (MACN-Ar 16278); same locality, 25.III.1995, Ramírez M. Goloboff P. Szumik C. & Faivovich J., 1 female (MACN-Ar 16264). San Luis: Merlo, ca. 32°09’S, 65°31’W, XI.1970, 1 female (MACN-Ar 16265). Córdoba: Cura Brochero, ca. 31°23'S, 64°11'W, IV.1994, Ramírez M., 1 female, 5 immatures (MACN-Ar 16263); Calamuchita, ca. 31°29'S, 64°13'W, I.1955, Viana J. M., 1 female (MACN-Ar 16274). Buenos Aires: Otamendi, ca. 34°13’S, 58°54’W, 25.IV.1998, Fuentes B., 1 female (MACN-Ar 16251); same locality and collector, 27.XII.1997, 1 female (MACN-Ar 16253); same locality and collector, 18.X.1997, 1 female (MACN-Ar 16258); same locality and collector, 1 female (MACN-Ar 16252); same locality and collector, 3 males (MACN-Ar 16250); same locality and collector, 4 females (MACN-Ar 16254); same locality and collector, 25.X.1997, 2 females (MACN-Ar 16256); same locality and collector, 9.I.1998, 3 females (MACN-Ar 16255); same locality and collector, 27.XII.1997, 1 female (MACN-Ar 16259); same locality and collector, 14.XII.1997, 3 females (MACN-Ar 16260); same locality and collector, 2 males (MACN-Ar 16257); Reserva Natural Otamendi, ca. 34°13’S, 58°54’W, pitfall traps, 25.X.1997, Fuentes B. & di Iorio O., 4 females (MACN-Ar 16240); same locality and collector, 28 males (MACN-Ar 16246); same locality and collector, 21.II.1998, 5 females (MACN-Ar 16239); same locality and collector, 15.XI.1997, 23 males (MACN-Ar 16237); same locality and collector, 18.X.1997, 4 females (MACN-Ar 16241); same locality and collector, 14 males (MACN-Ar 16247); same locality and collector, 1 male (MACN-Ar 16245); same locality and collector, 24.I.1998, 7 females (MACN-Ar 16243); same locality and collector, 1 male (MACN-Ar 16242); same locality and collector, 9.I.1998, 2 females (MACN-Ar 16248); same locality and collector, 1 male (MACN-Ar 16244); same locality and collector, 15.XI.1997, 1 female (MACN-Ar 16249); same locality and collector, 15.II.1998, 2 males (MACN-Ar 16238); Reserva Natural Otamendi, Est. Río Luján, 34°16'45.1"S, 58°53' 15.1 W, 4m., 25–7.III–IV.2007, Grismado C., Damer L., López N., Olejnik N., Crudele I., 1 female, 1 immature (MACN-Ar 12342); same locality, 19.V.2007, C. Grismado, S. Trivero, N. Olejnik & I. Crudele, 1 male (MACN-Ar 12514); same locality, 30.VI.2007, C. Grismado, L. Damer, N. López, S. Trivero & N. Olejnik, 1 male, 22 immature (MACN-Ar 12662); same locality, 30–28.VI–VII.2007, Grismado C., Damer L., Crudele I., Olejnik N., Trivero S., López N., de Biase S., 1 female (MACN-Ar 12827); Atucha, ca. 33°58’S, 59°17’W, 15.IX.1999, Ramírez M., 1 female, 4 immatures (MACN-Ar 16266); same locality, 27.VIII.1991, Ramírez M., 1 female (MACN-Ar 16261); Bella Vista, ca. 34°35’S, 58°42’W, IV.2003, Piacentini L., 2 males, 3 females (MACN-Ar 16262); General Madariaga, ca. 37°00’S, 57°08'W, XII.1952, De Carlo and D´Amico, 1 male, 7 female (MACN-Ar 3743); Isla Martín García, ca. 34°09'S, 58°15'W, 1940, Viana J. M., 1 male, 1 female, 2 immatures (MACN-Ar 16273); San Fernando, ca. 34°26’S, 58°33’W, XII.2002, Piacentini L., 1 female, 1 immature (MACN-Ar 16236); same locality, 1 female (MACN-Ar 16269); Don Torcuato, ca. 34°30'S, 58°39'W, X.2002, Piacentini L., 1 male, 1 female (MACN-Ar 16268); same locality, 1 female (MACN-Ar 16267); same locality, VIII.2002, Piacentini L., 2 males, 2 females (MACN-Ar 16271); same locality, I.2002 Piacentini L., 2 males, 1 female (MACN-Ar 16277); Sierra de los Padres, ca. 37°56'S, 57°46'W, XI.1962, Galiano M. E., 2 females (MACN- Ar 16279); Tigre, 2.XI.1951, Viana J. M., 4 females (MACN-Ar 16272); same locality and collector, 17.VII.1951, 2 males, 1 females, 2 immatures (MACN-Ar 16270); same locality and collector, 2.X.1950, 1 female (MACN-Ar 3052).
Diagnosis. Males of L. humilis differ from L. corondaensis and L. ojangureni by a narrower palp with a shorter embolus, and by the shorter median apophysis that barely surpasses the ventral part of the tegulum; the median apophysis converges with the terminal apophysis, which has a pointed, not strongly curved tip (Figs 6–8, 43–44). The male palp resembles those of L. otamendi sp. nov., but L. humilis have a less conspicuously peaked projection on the retrolateral tegular lobe, and a less curved profile of the cymbium (Figs 43–44). Lobizon humilis is larger and lacks the contrasting pattern on the opisthosoma (Figs 33–38). Females resemble those of L. minor and L. ojangureni sp. nov. in their rounded copulatory openings with elevated borders, but the median field is straight, not projecting in a lip (Figs 11, 39); the copulatory ducts have a different trajectory (Figs 12, 40, 42), passing usually between the spermathecal heads, not diverging laterally as in L. minor and L. ojangureni sp. nov.
Description. Male (MACN-AR 16257). Dorsal shield of prosoma brown with grey radial pattern, light brown median band narrowing posteriorly and pale submarginal bands. Dorsal shield of prosoma median band with few long black bristles from the fovea to the PLE; four long black bristles on the clypeal condyle anteriorly of AER. Sternum yellow, sparsely covered with brown bristles, more abundant on the margins.
Labium dark grey. Chelicerae darker than labium, reddish-brown, covered with brown bristles. Colour and pattern of the opisthosoma in dorsal view as in L. corondaensis; venter yellow with some dusk patches; spinnerets yellow. Legs brown with dark annulations. Leg formula IV> I> III> II; spination of leg I: femur, three dorsal, one apico-prolateral; tibia, three ventral pairs, and one prolateral; metatarsus, three ventral pairs and two prolateral spines (one in the centre, one apical). Palp with a dense retrolateral patch of bristles on the femur. Bulb with short embolus of prolateral apical origin, tegulum subdivided, the retrolateral tegular lobe have a conspicuous peaked projection (Figs 8, 43–44), terminal apophysis long with the terminal part slightly curved retro-dorsally, median apophysis small and laminar, longitudinal. The basal embolic lateral outgrowth is folded, seemingly a roll (Figs 6–8, 41, 43). The sperm ducts run ventrally from the retrolateral to prolateral, and make a loop in the middle of the ventral side of the tegulum.
Female (MACN-Ar 16239).
Colouration and setae arrangement as in male. Leg formula IV> I> III> II; spination of leg I: femur, three dorsal, one apico-prolateral; tibia, three ventral pairs, one prolateral; metatarsus, three ventral pairs. Epigyne with rounded copulatory openings with elevated borders, the posterior margin is straight (Figs 11, 39); copulatory ducts passing between the spermathecal heads. Dictynoid pore conspicuous, located on common base of vulval chambers and stalk of the spermathecae (Fig. 12).
Measuraments. Female, MACN-Ar 16239 (male, MACN-AR 16257): TL 5.16 (4.87), PL 2.83 (2.70), PW 2.00 (2.00), PH 0.93 (0.90), OL 2.33 (2.17). Eyes: AME 0.07 (0.07), ALE 0.07 (0.07), PME 0.28 (0.28), PLE 0.21 (0.21). Row of eyes: AM 0.50 (0.50), PME 0.67 (0.69), PLE 0.86 (0.86). Sternum (length/width) 1.30/1.07 (1.23/1.07). Labium (length/width) 0.39/0.40 (0.34/0.36). Legs: length of segments (femur + patella/tibia + metatarsus + tarsus = total length): Pedipalp 1.00 + 0.93 + - + 0.77 = 2.70, I 1.80 + 2.30 + 1.30 + 0.73 = 6.13, II 1.67 + 2.13 + 1.30 + 0.77 = 5.87, III 1.67 + 1.80 + 1.50 + 0.77 = 5.74, IV 2.17 + 3.80 + 2.33 + 0.97 = 9.27 (Pedipalp 1.00 + 0.93 + - + 0.70 = 1.80, I 1.80 + 2.37 + 1.40 + 0.77 = 6.34, II 1.67 + 2.13 + 1.40 + 0.77 = 5.97, III 1.57 + 1.87 + 1.47 + 0.77 = 5.68, IV 2.13 + 2.60 + 2.37 + 0.97 = 8.07).
Variation. Females (males) (range, mean±s.d.): TL 3.17 – 5.24, 4.27±0.70; CL 1.73 – 2.50, 2.20±0.28; CW 1.27 – 1.80, 1.60±0.17; n = 10; (TL 2.82 – 5.20, 4.03±0.65; CL 1.62 – 2.73, 2.29±0.31; CW 1.17 – 1.97, 1.60±0.23; n = 10). The female specimens from Santa Fe and Córdoba are considerably smaller, have shorter copulatory ducts and relatively smaller vulval chambers (as in Fig. 42), but their epigynes are almost identical to those from Buenos Aires Province. The male from Santa Fe is also comparatively small, but the palp is identical to those of the typical specimens.
Synonymy. The type of A. unguiculata was compared with large samples of females of A. humilis and we found no significant morphological differences.
Distribution. Central and central-eastern Argentina (San Luis, Córdoba, Santa Fe, Corrientes and Buenos Aires Province) (Fig. 85).
Natural history.The data from the Mburucuyá National Park, Corrientes (Rubio et al. 2008) suggests that, unlike L. corondaensis, this species prefers open grasslands. In the Reserva Natural Otamendi, where the largest series was collected, most spiders were found beating the bases of grasses in a halophilous grassland near Río Luján, and by pitfall traps in the “chilcal” (Baccharis sp.), although several specimens were also caught by the same method in the “talar” (forest of Celtis tala). The specimens from Atucha were collected with Berlese funnels (data from the label), and the specimens from Don Torcuato (Buenos Aires metropolitan area) were caught under moist vegetation in suburban gardens.
description: Published as part of Piacentini, Luis N. & Grismado, Cristian J., 2009, Lobizon and Navira, two new genera of wolf spiders from Argentina (Araneae: Lycosidae), pp. 1-33 in Zootaxa 2195 on pages 19-21, DOI: 10.5281/zenodo.189469