Centroctenus varzea Brescovit & Torres & Rego & Polotow 2020, sp. nov.
Creators: name: Brescovit, Antonio D.
name: Torres, Richard A.
name: Rego, Felipe N. A. A.
name: Polotow, Daniele
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Ctenidae
Centroctenus
Centroctenus varzea

description: Centroctenus varzea sp. nov.
Figures 9–11, 12C
Type material. Male holotype from Nossa Senhora de Fátima (2°46’55”S, 57°55’01”W), Ilha Grande Cucuiari, Urucurituba, Amazonas, Brazil, 04.XI.2003, F. Rego & C. A. Rheims coll., sample A698 (IBSP 162675). Paratypes: 1 female from Vila do Jacaré (3°37’41”S, 60°50’28”W), Paranã do Jacaré, Manacapuru, 29.IX.2003, F. Rego & E. Venticinque coll., sample A128 (MPEG 1187); 1 male and 2 females from Nossa Senhora de Fátima (2°46’55”S, 57°55’01”W), Ilha Grande Cucuiari, Urucurituba, 4.XI.2003, F. Rego & C. A. Rheims coll., sample A594 (MPEG 1182), 1 male, ditto, sample A600 (MPEG 1186), 1 male from Nossa Senhora do Perpétuo Socorro (3°09’14”S, 59°19’26”W), Matinha, Itacoatiara, 7.XI.2003, F. Rego & C. A. Rheims coll., sample A57 (IBSP 162627); 1 female from Recreio (2°04’34”S, 55°57’58”W), Malagueta, Juruti, Pará, 30.X.2003, F. Rego & C. A. Rheims coll., sample A663 (IBSP 162671), all from Brazil.
Additional material examined. BRAZIL: Amazonas. Tabatinga, Terra Firme Palmares, Palmares (4°00’50”S, 69°27’50”W), 11.IX.2003, sample A221, 1 female (IBSP 162641); Santo Antônio do Içá, Lago Chicotuba / Paranã Canini, Presidente Vargas (3°10’23”S, 68°01’52”W), 15.IX.2003, sample A225, 1 male (IBSP 162642); Tefé, Guariba-Solimões, São João do Catuá (3°39’50”S, 64°10’12”W), 22.IX.2003, samples A319, A338, A369, A311, A175; 4 males, 3 females (MPEG 1178; IBSP 162640; 162648; 162649; 162651); Tefé, Lago do Jacaré, São Francisco do Capivara (3°15’36”S, 64°37’41”W), 21.IX.2003, sample A262, A317, A344; 2 males, 2 females (MPEG 1183; IBSP 162645; 162650); Codajás, Lago Cuxuara, Urucurizinho (3°58’19”S, 61°57’36”W), 26.IX.2003, sample A111, A136, A151, A161; 5 females (MPEG 1185; IBSP 162631; IBSP 162634; IBSP 162639); Manacapuru, Paranã do Jacaré, Vila do Jacaré (3°37’41”S, 60°50’28”W), 29.IX.2003, sample A112, A137; 3 males, 2 females (IBSP 162632; 162635), all collected by F. Rego & E. Venticinque; Itacoatiara, Matinha, Nossa Senhora do Perpétuo Socorro (3°09’14”S, 59°19’26”W), 07.XI.2003, sample A85, A96; 4 females (MPEG 1180; IBSP 162630); Itacoatiara, Trindade, São José (3°18’32”S, 58°42’36”W), 6.XI.2003, samples A63, A92; 4 females (IBSP 162628; IBSP 162629); Urucurituba, Ilha Grande Cucuiari, Nossa Senhora de Fátima (2°46’55”S, 57°55’01”W), 4.XI.2003, 6 males, 8 females, samples A607, A646, A715, A744, A641, A612, A628, A604, A681, A593, A600 (MPEG 1184; 1186; IBSP 162673 [automontage]; 162659; 162660; 162661; 162663; 162667; 162669; 162676; 162678); Parintins, Ilha do Meio, Menino Deus (2°31’19”S, 56°31’44”W), 1.XI.2003, sample A654, A723; 2 females (IBSP 162670; 162677), all collected by F. Rego & C. A. Rheims; Pará. Almeirim, Munguba, Arumanduba (1°28’48”S, 52°26’31”W), 1 male, 1 female, 20.X.2003 sample A519 (IBSP 162655); Gurupá, Furinho, São José (1°12’14”S, 51°49’05”W), 1 female, 18.X.2003, sample A566 (IBSP 162658); Juruti, Malagueta, Recreio (2°04’34”S, 55°57’58”W), 30.X.2003, samples A666, A616, A663; 3 females (IBSP 162662; 162671; 162672), all collected by F. Rego & C. A. Rheims.
Etymology. Várzea is a Portuguese noun for freshwater swamp forest or flooded forest. The Amazon River Basin and its tributaries are characterized by extensive forested areas that become flooded every rainy season, where specimens listed above have been collected.
Diagnosis. Males of Centroctenus varzea sp. n. resemble those of C. acara (Brescovit 1996: figs 25–26) by the size and position of median apophysis, but can be distinguished by median apophysis curved at tip, non-sinuous embolus, cymbium basally narrow, and by the large tip of the RTA (Fig. 9A). Females of Centroctenus varzea sp. n. resemble those of C. acara (Brescovit 1996: fig 27) by the lateral lobes conic, but can be distinguished by the lateral lobes projected posteriorly and the subquadrangular median sector of the epigynum (Fig. 9B).
Description. Male (holotype). Carapace reddish brown, with a subpentagonal white setae area around the fovea, in the cephalic area, lateral areas and in both sides of the median eyes; the remaining carapace is covered by black setae; chelicerae dark reddish brown, covered with white setae prolaterally; palp, legs and sternum light reddish brown, covered with short black setae; legs also covered with short and long white setae; abdomen yellow dorsally and laterally, covered by short black and white setae and elongated white setae; venter of abdomen black, covered with black setae and with white setae in the central area (Fig. 11A, B, E). Total length 16.7. Carapace 9.10 long and 7.2 wide. Clypeus 0.37 high. Eye diameters: AME 0.35, ALE 0.25, PME 0.4, PLE 0.45. Chelicerae with 3 promarginal teeth, median larger; 4 retromarginal teeth, basal small; with intermarginal denticles. Leg measurements: I: femur 7.9/ patella 3.6/ tibia 7.3/ metatarsus 6.8/ tarsus 2.3/ total 27.9; II: 7.5/ 3.5/ 6.4/ 6.25/ 2.2/ 25.85; III: 6.1/ 2.9/ 5.10/ 5.50/ 1.8/ 21.4; IV: 8.7/ 3.25/ 7.3/ 9.3/ 2.5/ 31.05. Leg formula 4123. Leg spination: tibia I v2-2-2-2-2, r1-1-0, p1-1-0, II v2-2-2-2-2, r1-1-0, p1-1-0, III v2-2-2, r1-1-0, p1-1-0, VI v2-2-2, r1-1-0, p1-1-0; metatarsus I v2- 2-2, r1-1-1, p1-1-0, II v2-2-2, r1-1-1, p-1-1-0, III v2-2-2, r1-1-1, p1-1-1, VI, v2-1-1-1-2, r1-1-1, p1-1-1; metatarsus IV unmodified. Palp (Fig. 9A): tibia as long as cymbium; RTA close to tibial apex, elongated, cylindrical proximally and laminar and wide distally; cymbium elongate, with basal excavation; tegulum not projected; embolus with large base, with retrolateral basal projection and cylindrical distally; median apophysis cup-shaped and short; conductor hyaline, round and laminar.
Female (paratype, MPEG 1187). Coloration as described in male, excepted by the venter of the abdomen entirely yellow, covered by short black and white setae and elongated white setae (Fig. 11C, D, F). Total length 22.0. Carapace 9.7 long and 7.2 wide. Clypeus 0.42 high. Eye diameters: AME 0.37, ALE 0.25, PME 0.42, PLE 0.42. Chelicerae with 3 promarginal teeth, median larger; 4 retromarginal teeth, with same size, and 2 small proximal teeth; with intermarginal denticles (Fig. 10D). Leg measurements: I: femur 6.6/ patella 3.7/ tibia 5.9/ metatarsus 5.5/ tarsus 1.8/ total 23.5; II: 6.5/ 3.7/ 5.5/ 5.1/ 1.8/ 22.6; III: 5.6/ 3.0/ 4.2/ 4.8/ 1.7/ 19.3; IV: 7.2/ 3.3/ 6.2/ 8.0/ 2.1/ 26.8. Leg formula 4123. Leg spination: tibia I-II v2-2-2-2-2, r0, p0, III v2-2-2, r1-1-0, p1-1-0; metatarsus I-II v2-2-2, r0, p0, III v2-2-2, r1-1-1, p1-1-1; IV v1-1-1-1-2, p1-1-1, r0-1-1. Tarsal trichobothria hood with transversal ridges (Fig. 10E). Capsulate tarsal organ with oval aperture (Fig. 10F). Female genitalia (Figs 9B, C, 10 A–C): median sector of epigynum subquadrangular, with a pair of excavations anteriorly; lateral lobes elongated, pointed posteriorly; copulatory ducts sinuous; head of spermathecae small, with large pores, and base of spermathecae round; short fertilization ducts.
Variation. Males (n=10): total length: 15.8–16.9; carapace length: 8.8–9.4; femur I length: 7.5–8.1. Females (n=10): total length: 21.2–23.9; carapace length: 9.2–10.6; femur I length: 5.1–6.9.
Natural history. Centroctenus varzea sp. n. is one of the most abundant spiders in the flooded forests (várzea) of the Amazon River (Rego et al. 2009). Eighty-nine specimens were collected in samples scattered approximately 3,000 km along the river, at both margins and at the end of the flood season (from September to early November/2003). C. varzea sp. n. is a nocturnal wandering spider, found foraging at the leaf litter near rivers, lakes and streams. Few specimens were collected at night on beaches and ravines, and three individuals (less than 4% of the total) were caught during the daylight on shrubs and bare soil in non-flooded forest (terra-firme). The high abundance of juveniles and adults even in wet soil after flooding suggests that C. varzea sp. n. returns to flooded forests as the water descends into the Amazon River and its tributaries.
Distribution. North of Brazil in the Amazon River basin (Fig. 12C).
description: Published as part of Brescovit, Antonio D., Torres, Richard A., Rego, Felipe N. A. A. & Polotow, Daniele, 2020, Six new species of the spider genus Centroctenus Mello-Leitão from the Neotropical region (Ctenidae, Cteninae), pp. 311-328 in Zootaxa 4877 (2) on pages 322-327, DOI: 10.11646/zootaxa.4877.2.5, http://zenodo.org/record/4424235