Ctenus nigritus F.O. Pickard-Cambridge 1897
Creators: name: Polotow, Daniele
name: Brescovit, Antonio D.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Ctenidae
Ctenus
Ctenus nigritus

description: Ctenus nigritus F.O. Pickard-Cambridge, 1897
Figs 3 A–D
Ctenus nigritus F. O. Pickard-Cambridge, 1897: 81, pl. 3, figs 6a, 7a (male holotype from Santarém, 2°26ˏ34ʺS, 54°42ˏ28ʺW, Pará, Brazil, 1896, E.E. Austen col., deposited in BMNH 1896.12.13.98, examined).
Diagnosis. Males of Ctenus nigritus resemble those of C. manauara (Höfer et al. 1994: fig. 7a–b) by the prominent ventral tegular projection, but can be distinguished by the larger RTA, which is truncated at the apex, and the shape of the retrolateral tibial apophysis (Figs 3 A–B). Females resemble those of C. manauara (Höfer et al. 1994: fig. 8a) by the shape of the epigynal median sector, but can be distinguished by the visible ovoid projection and the apical position of the lateral sector processes (Fig. 3 C).
Note. The holotype is faded; the colour description is based on the male and female deposited in MPEG 6939.
Description. Male (holotype). Colouration: carapace reddish brown, pars thoracica pale brown, thoracic groove dark brown; black rings around eyes; legs reddish brown, with ventral faces of coxae and femora lighter; chelicerae reddish brown; endites and labium reddish brown, lighter at tips; sternum reddish brown; abdomen gray with several small black spots, with dorsal anterior light area and two gray dark spots in dorsal median area; ventral abdomen with V-shaped black area, from epigastric furrow to spinnerets, with two white spots near epigastric furrow. Total length 14.50. Carapace 8.00 long and 6.20 wide. Clypeus 0.32 high. Eye diameters: AME 0.40, ALE 0.25, PME 0.42, PLE 0.50. Chelicerae with 3 promarginal teeth, median larger; 4 retromarginal teeth, basal small; with intermarginal denticles. Leg measurements: I: femur 9.00/ patella 3.60/ tibia 8.80/ metatarsus 8.60/ tarsus 2.80/ total 32.80; II: 8.70/ 3.30/ 8.60/ 8.20/ 2.40/ 31.20; III: 7.40/ 3.00/ 6.30/ 7.40/ 2.00/ 26.10; IV: 9.60/ 3.20/ 8.20/ 12.00/ 2.90/ 35.90. Leg formula 4123. Leg spination: tibia I and II v2-2 -2-2-2, r1-1-0, p1-1-1-0, III and IV v2-2 -2, r1-1-0, p1-1-0; metatarsus I, II v2-2 -2, r1-1-0, p-1-1-0, III v2-2 -2, r1-1-1, p1-1-1; metatarsus IV unmodified. Palp: tibiae as long as cymbium; RTA on apical margin of tibia, short, broad and flattened, pointed ventrally; cymbium elongate, without basal projections; tegulum projected; embolus with large base, short tip and with laminar basal projection; median apophysis cup-shaped, bimarginate and short; conductor hyaline, C-shaped in retrolateral view (Figs 3 A–B).
Female (MPEG 6889). Colouration as in male. Total length 15.60. Carapace 6.80 long and 5.60 wide. Clypeus 0.22 high. Eye diameters: AME 0.28, ALE 0.17, PME 0.34, PLE 0.36. Chelicerae with 3 promarginal teeth, median larger; 4 retromarginal teeth, basal small; with intermarginal denticles. Leg measurements: I: femur 6.10/ patella 3.00/ tibia 5.70/ metatarsus 5.10/ tarsus 1.70/ total 21.60; II: 5.80/ 2.90/ 5.00/ 4.90/ 1.70/ 20.30; III: 5.20/ 2.60/ 3.90/ 4.70/ 1.60/ 18.00; IV: 6.40/ 2.50/ 5.60/ 8.10/ 2.10/ 24.70. Leg formula 4123. Leg spination: tibia I and II v2- 2 -2-2-2, r0, p0, III and IV v2-2 -2, r1-1, p1-1; metatarsus I, II v2-2 -2, r0, p0, III v2-2 -2, r1-1, p1-1, IV v1-1 -1-2-2, r1-1, p1-1. Epigynum: median sector subrectangular, invaginated anteriorly; with two projecting ovoid lobes; lateral spurs originating medially in lateral sector (Fig. 3 C); oval spermathecae; copulatory ducts, long, large and curved; fertilization duct short, originating from retrolateral side of spermathecae (Fig. 3 D).
Variation. 10 males: total length 14.50–24.50; carapace 8.00–13.70 long; femur I 9.00–14.20. 10 females: total length 15.60–26.70; carapace 6.80–12.60 long; femur I 6.10–10.30.
Additional material examined. BRAZIL. Pará: Almeirim, Laranjal do Jari (00o35'27.94271"S 52o44'9.24822"W), 3 females (MPEG 6893, 6908); 1 female (MPEG 6926); (00o41'25.93745"S 52o49'9.21553"W) 4 males and 5 females (MPEG 6894, 6895, 6914, 6927, 6932, 6939, 6951); (00o41'45.28868"S 52o48'32.29253"W), 1 female (MPEG 6935); 2 males (MPEG 6899, 6901); (00o42'33.18001"S 52o46'57.49371"W), 11 females (MPEG 6913, 6915, 6920); 1 male and 11 females (MPEG 6898, 6902, 6906, 6936, 6945, 6949); (00o42'42.64747"S 52o40'0.86094"W), 1 female (MPEG 6943); (00o42'8.76351"S 52o38'8.94836"W), 1 male and 3 females (MPEG 6888, 6942, 6954, 7595); (00o49'58.65601"S 52o39'29.69148"W), 1 female (MPEG 6934); (00o53'16.53963"S 52o50'41.59495"W), 1 female (MPEG 6950); (01o01'32.45885"S 52o54'17.27678"W), 2 females (MPEG 6918, 6937); 5 males and 4 females (MPEG 6911, 6925, 6931, 6938, 6953); (01o01'33.12220"S 52o34'2.78573"W), 2 males and 3 females (MPEG 6886, 6940, 6947); (01o11'28.30705"S 52o38'51.85530"W), 2 males and 4 females (MPEG 6892, 6896, 6904, 6941, 6952); (01o35'13.05213"S 52o39'31.63974"W), 2 females (MPEG 6889, 6897, 6929); (01o36'14.72106"S 52o39'9.44026"W), 1 female (MPEG 6916); Melgaço (Estação Científica Ferreira Penna, FLONA Caxiuanã, 0 1o 44'15.5" S 51o26'42.0"W), 1 male and 1 female (MPEG 9322); Juruti (Ramal Pacoval, km 2, 0 2o 28'0.6" S 56o12'42.2"W), 1 male (MPEG 14930); (Comunidade Café Torrado), 3 males and 1 female (MPEG 14004, 14931, 14932).
Distribution. North of the State of Pará, Brazil (Fig. 7).
description: Published as part of Polotow, Daniele & Brescovit, Antonio D., 2012, Redescription of five Amazonian species of Ctenus Walckenaer (Araneae, Ctenidae, Cteninae), pp. 49-59 in Zootaxa 3338 on pages 52-54, DOI: 10.11646/zootaxa.3338.1.3, http://zenodo.org/record/281372