Isoctenus guadalupei ( Mello-Leitão, 1941 ),

Polotow, Daniele & Brescovit, Antonio D., 2019, Almost eight decades later: description of the male of Isoctenus guadalupei (Mello- Leitão, 1941) comb. nov. and redescription of the female, Zootaxa 4683 (2), pp. 291-294: 292-293

publication ID

publication LSID


persistent identifier

treatment provided by


scientific name

Isoctenus guadalupei ( Mello-Leitão, 1941 )

comb. nov.

Isoctenus guadalupei ( Mello-Leitão, 1941)  comb. nov.

Figures 1−3View FIGURE 1View FIGURE 2View FIGURE 3

Ctenus guadalupei Mello-Leitão, 1941: 215  , figs 23–24 (female holotype from Guadalupe Norte [-28.9408, -59.5624], Província de Santa Fé, Argentina, M. Birabén coll., deposited in MLP 15180View Materials, examined); World Spider Catalog 2019.

Note. Type specimen with faded coloration and missing leg IV segments, except the femur and coxae. The male was matched by similarities of size and coloration, and by the close proximity from the type locality.

Additional material examined. ARGENTINA. Corrientes: Mburucuyá, Parque Nacional Mburucuyá (Sendero Che Roga, -28.0049, -58.0365, 85 m. a.s.l., manual collecting), 1 male, 27–30.V.2011, G. Rubio, M. Izquierdo & L. Piacentinni coll. (MACN-Ar 30496)GoogleMaps  .

Diagnosis. Males of Isoctenus guadalupei  comb. nov. ( Fig. 2AView FIGURE 2) resemble those of I. ordinario  ( Polotow & Brescovit, 2009: fig. 9A–B) by the elongated dorsal branch of RTA, bifid tip of embolus and shape of median apophysis, but it can be distinguished by the presence of a basal retrolateral projection of embolus (RPE), shorter tibia of palp and cymbium, and embolus with larger base. Males of Isoctenus guadalupei  also present a projection on each coxae IV ( Fig. 1CView FIGURE 1), which is absent in I. ordinario  . Females of Isoctenus guadalupei  resemble those of I. ordinario  by the cordiform shape of the median field of epigynum and anterior position of lateral fields projections, but can be distinguished by the median field less excavated apically ( Fig. 2BView FIGURE 2) and the larger spermathecae and copulatory ducts ( Fig. 2CView FIGURE 2).

Description. Male (MACN-Ar 30496). Prossoma uniformly orange, darker in the dorsum; with brown thoracic groove and black rings around eyes; greyish dorsal opistossoma with light brown dorsal, folium-like marking ( Fig. 1View FIGURE 1 A−B). Total length 10.20. Carapace 5.60 long and 4.35 wide. Eye diameters: AME 0.20, ALE 0.20, PME 0.25, PLE 0.24. Leg measurements: I: femur 6.90/ patella 2.80/ tibia 7.10/ metatarsus 6.87/ tarsus 3.00/ total 26.67; II: 5.93/ 2.55/ 5.80/ 5.90/ 2.55/ 22.73; III: 5.16/ 2.00/ 5.00/ 5.65/ 2.15/ 19.96; IV: 7.00/ 2.25/ 6.70/ 8.90/ 2.90/ 27.75. Leg spination: tibia I-II v2-2-2-2-2, r0, p0, III-IV v2-2-2, r1-1, p1-1; metatarsus I-II v2-2-2, r0, p0, III v2-2-2, r1-1-1, p-1-1-1, IV v1-1-1-1- 1-2, r1-1-1, p1-1-1. Coxa IV with a ventral projection ( Fig. 1CView FIGURE 1). Palp ( Figs 1DView FIGURE 1, 2AView FIGURE 2): tibia approximately two thirds of cymbium length; RTA with ventral branch subtriangular; tibia with short and curved ventral apophysis; cymbium with ventral retrolateral projection reduced and dorsal retrolateral projection rounded; short and laminar embolus, with bifid tip and short basal projection; robust median apophysis, with conical anterior and posterior projections.

Female ( MLP 15180View Materials). Coloration faded, ranging from light brown to beige in the whole specimen. Total length 11.60. Carapace 5.50 long and 4.20 wide. Clypeus 0.17 high. Eye diameters: AME 0.26, ALE 0.20, PME 0.31, PLE 0.27. Leg measurements: I: femur 5.20/ patella 2.50/ tibia 5.00/ metatarsus 4.20/ tarsus 1.80/ total 18.70; II: 4.70/ 2.60/ 4.40/ 3.80/ 1.60/ 17.10; III: 4.20/ 2.00/ 3.50/ 3.70/ 1.50/ 14.90; IV: 5.60/ -/ -/ -/ -/ -. Leg spination: tibia I-II v2-2-2-2-2, r0, p0, III-IV v2-2-2, r1-1, p1-1; metatarsus I-II v2-2-2, r0, p0, III v2-2-2, r1-1-1, p-1-1-1. Epigynum ( Fig. 2View FIGURE 2 B−C): subrounded median field; lateral spurs short, partially covered by the median field and with a pointed tip. Spermathecae with rounded head and large base.

Distribution. Corrientes and Santa Fé Provinces, northeastern Argentina ( Fig. 3View FIGURE 3). Isoctenus ordinario  is commonly found in the Parana Dominion of Brazil and Argentina, while I. guadalupei  is only found in the Chacoan province (part of the Chacoan Dominion) ( Fig. 3View FIGURE 3).














Isoctenus guadalupei ( Mello-Leitão, 1941 )

Polotow, Daniele & Brescovit, Antonio D. 2019

Ctenus guadalupei Mello-Leitão, 1941: 215

Mello-Leitao, C. F. de 1941: 215