Mesabolivar aurantiacus
Creators: name: Huber, Bernhard A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Mesabolivar
Mesabolivar aurantiacus

description: Mesabolivar aurantiacus (Mello-Leitão, 1930)
Figs 78–81, 98–99, 106–107
Blechroscelis aurantiacus Mello-Leitão, 1930: 61, fig. 13 (♂, Brazil: Pará).
Blechroscelis irroratus Mello-Leitão, 1947a: 160, figs 4–5 (♂♀, Brazil: Pará). Synonymized in Huber 2000: 206.
Blechroscelis virescens Mello-Leitão, 1947a: 161, fig. 6 (♂, Guyana). Synonymized in Huber 2000: 206.
Psilochorus cambridgei Mello-Leitão, 1947a: 163 (♂♀, Brazil: Pará); name preoccupied (Psilochorus cambridgei Gertsch & Davis, 1937).
Psilochorus browningi Roewer, 1951: 455; new name for Psilochorus cambridgei Mello-Leitão, 1947a. Synonymized in Huber 2000: 206.
Mesabolivar aurantiacus: Huber 2000: 206, figs 42, 43, 81, 801–810.
Autana autanensis González-Sponga, 2011b: 40, pl. 1, figs 1–7 (♂, Venezuela). Synonymized in Huber et al. 2014a: 419.
Misidentification
Mesabolivari pseudoblechroscelis: González-Sponga 1998: 27, figs 40–41 (♀ paratype only).
Diagnosis. (amendments; see Huber 2000). Easily distinguished from similar congeners (M. spinosus, M. cyaneus, M. macushi) by male procursus (distinctive ventral process and sclerite embedded in membrane; Figs 98–99), by tip of male bulbal process (Figs 106–107; mostly membranous with slender process, similar to M. macushi), and by epigynal pocket continuing anteriorly into long furrow (Huber 2000: fig. 808). From M. spinosus also by much more slender palpal femur.
Type material. Blechroscelis aurantiacus Mello-Leitão, 1930: BRAZIL: Pará: 2♂ syntypes, MNRJ, Cuminá [1.35°S, 56.05°W], no further data, examined (Huber 2000).
Blechroscelis irroratus Mello-Leitão, 1947: BRAZIL: Pará: 1♀ type (? – see Huber 2000), BMNH (1897.9.21 501–508), Breves [1.68°S, 50.47°W], leg. F.O. Pickard-Cambridge, examined (Huber 2000).
Blechroscelis virescens Mello-Leitão, 1947: GUYANA: 1♂ type (? – see Huber 2000), BMNH (1897.8.5.3.8), Higher Potaro River [~ 5.1°N, 59.5°W], examined (Huber 2000).
Psilochorus cambridgei Mello-Leitão, 1947: BRAZIL: Pará: 1♀ type, BMNH (1897.9.20 501–508), Breves [1.68°S, 50.47°W], no further data, examined (Huber 2000).
Autana autanensis González-Sponga, 2011: VENEZUELA: Amazonas: ♂ holotype, MIZA (MAGS 1162), Municipio Autana, Rio Autana (4°55’N, 67°24’W, 250 m), iii.1989 (S. Obispo), not examined.
New material examined. BRAZIL: Pará: 10♂ 4♀, ZFMK (Ar 18963), Belém, Parque Estadual do Utinga, ‘site 1’ (1.424°S, 48.429°W), 25 m a.s.l., 5.x.2016 (B.A. Huber, L.S. Carvalho); 3♀ in pure ethanol, ZFMK (Br 16- 234), same data. 14♂ 9♀, ZFMK (Ar 18964–65), Belém, Parque Estadual do Utinga, ‘site 2’ (1.433°S, 48.410°W), 25 m a.s.l., 5–6.x.2016 (B.A. Huber, L.S. Carvalho); 1♂ 2♀ in pure ethanol, ZFMK (Br 16-228a), same data. 8♂ 3♀, ZFMK (Ar 18966), Marabá, forest near road, ‘site 1’ (5.414°S, 49.074°W), 140 m a.s.l., 7–8.x.2016 (B.A. Huber, L.S. Carvalho); 1♂ 1♀ in pure ethanol, ZFMK (Br 16-237), same data. 3♂ 9♀, ZFMK (Ar 18967), Serra Pelada (5.931°S, 49.674°W), 140 m a.s.l., rocky hill, 9.x.2016 (B.A. Huber, L.S. Carvalho); 2♀ 1 juv. in pure ethanol, ZFMK (Br 16-242), same data. 3♂ 4♀, ZFMK (Ar 18968), Floresta Nacional de Tapajós, km 67, ‘site 1’ (2.847°S, 54.972°W), 180 m a.s.l., 15.x.2016 (B.A. Huber, L.S. Carvalho). 3♂ 3♀, ZFMK (Ar 18969), Floresta Nacional de Tapajós, km 67, ‘site 2’ (2.875°S, 54.941°W), 190 m a.s.l., 15.x.2016 (B.A. Huber, L.S. Carvalho). 1♀, ZFMK (Ar 18970), Floresta Nacional de Tapajós, km 72, ‘site 2’ (2.940°S, 54.933°W), 140 m a.s.l., 17.x.2016 (B.A. Huber, L.S. Carvalho). 2♂ 2♀, ZFMK (Ar 18971), Floresta Nacional de Tapajós, km 83 (3.049°S, 54.928°W), 95 m a.s.l., 14–18.x.2016 (B.A. Huber, L.S. Carvalho). 5♂ 3♀, ZFMK (Ar 18972), Floresta Nacional de Tapajós, km 221 (4.046°S, 54.938°W), 80 m a.s.l., 16.x.2016 (B.A. Huber, L.S. Carvalho); 1♂ in pure ethanol, ZFMK (Br 16-276), same data.
Amapá: 7♂ 10♀, ZFMK (Ar 18973), forest SW Macapá, ‘site 1’ (0.051°S, 51.136°W), 25 m a.s.l., 12.x.2016 (B.A. Huber, L.S. Carvalho); 2♂ 2♀ in pure ethanol, ZFMK (Br 16-246), same data. 3♂ 2♀, ZFMK (Ar 18974), forest SW Macapá, ‘site 2’ (0.051°S, 51.123°W), 20 m a.s.l., 12.x.2016 (B.A. Huber, L.S. Carvalho). 2♂ 3♀, ZFMK (Ar 18975), forest SW Macapá, ‘site 4’ (0.057°S, 51.234°W), 25 m a.s.l., 13.x.2016 (B.A. Huber, L.S. Carvalho); 1♀ 2 juvs in pure ethanol, ZFMK (Br 16-254), same data.
Amazonas: 9♂ 11♀, ZFMK (Ar 18976), Manaus, Reserva Ducke (2.932°S, 59.970°W), 80 m a.s.l., 5– 6.xi.2016 (B.A. Huber, L.S. Carvalho); 1♀ in pure ethanol, ZFMK (Br 16-332), same data. 9♂ 6♀, ZFMK (Ar 18977), Presidente Figueiredo, Maroaga Cave and surrounding forest (2.050°S, 59.972°W), 110–150 m a.s.l., 7.xi.2016 (B.A. Huber, L.S. Carvalho); 1♂ 2♀ in pure ethanol, ZFMK (Br 16-340), same data. 6♂ 7♀, ZFMK (Ar 18978–79), forest near Humaitá, ‘site 2’ (7.563°S, 63.116°W), 65 m a.s.l., 20–21.x.2016 (B.A. Huber, L.S. Carvalho); 2♀ in pure ethanol, ZFMK (Br 16-287), same data. 7♂ 1♀, ZFMK (Ar 18980), forest near Humaitá, ‘site 3’ (7.512°S, 63.393°W), 80 m a.s.l., 22.x.2016 (B.A. Huber, L.S. Carvalho); 1♂ 2 juvs in pure ethanol, ZFMK (Br 16-293), same data. 12♂ 9♀, ZFMK (Ar 18981), forest near Tabatinga (4.244°S, 69.92–69.93°W), 90 m a.s.l., 2–4.xi.2016 (B.A. Huber, L.S. Carvalho); 1♀ in pure ethanol, ZFMK (Br 16-324), same data.
Rondônia: 1♀, ZFMK (Ar 18982), Floresta Nacional do Jamari, ‘site 1’ (9.193°S, 63.107°W), 130 m a.s.l., 23.x.2016 (B.A. Huber, L.S. Carvalho); 1 juv. in pure ethanol, ZFMK (Br 16-294), same data. 3♂, ZFMK (Ar 18983), Floresta Nacional do Jamari, ‘sites 2 & 3’ (9.22°S, 62.93°W – 9.26°S, 62.92°W), 110 m a.s.l., 24.x.2016 (B.A. Huber, L.S. Carvalho). 2♂, ZFMK (Ar 18984), Floresta Nacional do Jamari, ‘sites 4 & 5’ (9.193°S, 63.037°W – 9.195°S, 63.082°W), 110–150 m a.s.l., 25.x.2016 (B.A. Huber, L.S. Carvalho).
Acre: 1♂ 3♀, ZFMK (Ar 18985), Rio Branco, Fazenda Experimental Catuaba (10.08°S, 67.625°W), 225 m a.s.l., 26–27.x.2016 (B.A. Huber, L.S. Carvalho); 2♂, ZFMK (Ar 18986), same locality at 10.078°S, 67.619°W, 200 m a.s.l., 29.x.2016 (B.A. Huber, L.S. Carvalho). 3♀, ZFMK (Ar 18987), Rio Branco, Reserva Florestal Humaitá (9.749°S, 67.666°W), 180 m a.s.l., 28.x.2016 (B.A. Huber, L.S. Carvalho); 1♂ in pure ethanol, ZFMK (Br 16-308), same data.
VENEZUELA: Bolívar: 1♂ 1♀, ZFMK (Ar 18988), km 102 from El Dorado (6°04’N, 61°24’W), ~ 500 m a.s.l., near ground, 2.xii.2002 (B.A. Huber). 3♂ 1♀, ZFMK (Ar 18989–90), km 44 from El Dorado (6°25’N, 61°38.5’W), ~ 200 m a.s.l., near ground, 2.xii.2002 (B.A. Huber).
GUYANA: Upper Takutu-Upper Essequibo: 1♀ in pure ethanol, ZFMK (G010), 4.42 km S Gunn's Strip, bank of Essequibo river (1.613°N, 58.638°W), 240 m a.s.l., 6–15.vii.1999 (J.A. Coddington et al.).
TRINIDAD AND TOBAGO: Trinidad: 6♂ 2♀ in pure ethanol, ZFMK (G001), Arena Forest [10.56°N, 61.23°W], 29.vi.2002 (C.K. Starr, J.N. Sewlal).
Description (amendments; see Huber 2000). Tibia 1 in 108 newly examined males: 10.5–18.9 (mean 15.2); in 85 newly examined females: 8.1–13.6 (mean 10.8). Femora 3 in most males strongly enlarged and of different color than other legs (reddish rather than dark brown to black; Fig. 78); only very small males with barely enlarged femora 3 (e.g., diameters of femora in male with tibia 1 length 16.7: 0.24, 0.24, 0.43, 0.24; in male with tibia 1 length 13.6: 0.19, 0.19, 0.23, 0.19); femora 3 in males from Maroaga Cave near Presidente Figueiredo not or only slightly lighter than other femora. Most males with spines on metatarsi 2 and 3, rarely only on metatarsi 2, only on metatarsi 3, or without spines (very small males); prolateral trichobothrium present on tibia 1. Coloration of males usually similar to females (Figs 78, 80), abdomen sometimes more reddish but with same pattern of dark internal marks; only in males from Reserva Ducke abdomen strongly reddish with few indistinct darker marks (Fig. 79). Most females with pair of anterior epigynal humps (cf. Huber 2000: figs 808–809), barely visible or absent in females from Reserva Ducke, Tabatinga, and Catuaba; anterior margin of epigynal plate in females from these localities more rounded than in females from other localities.
Natural history. The spiders were found in large domed webs with a diameter of up to 50 cm, usually among buttresses of trees and under large tree logs, but sometimes also under large dead leaves on the ground (e.g., palm leaves; Manaus), or higher among the vegetation (especially juveniles). There seemed to be a locality-specific tendency with respect to the degree of exposure: at some localities the webs were mostly hidden in large sheltered spaces (Marabá, Tapajós, Jamari, Rio Branco), in others, most webs were rather exposed, often with the sun directly reaching the spiders (Belém, Humaitá, Tabatinga). They were also found in the twilight zone of caves, where they occupied the lower spaces up to 1 m above the ground (Maroaga Cave near Figueiredo; unnamed cave in Serra Pelada). At some localities, the spiders were extremely abundant. When disturbed, they started swinging strongly, moving the entire webs with them. In Arena Forest (Trinidad), Sewlal & Starr (2008) found ~25% of M. aurantiacus webs containing the nabid bug Arachnocoris trinitatis.
Distribution. Widely distributed in northern South America (Fig. 724).
description: Published as part of Huber, Bernhard A., 2018, The South American spider genera Mesabolivar and Carapoia (Araneae, Pholcidae): new species and a framework for redrawing generic limits, pp. 1-178 in Zootaxa 4395 (1) on pages 29-30, DOI: 10.11646/zootaxa.4395.1.1, http://zenodo.org/record/1202519