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

description: Mesabolivar brasiliensis (Moenkhaus, 1898)
Figs 274–279, 298–299
Litoporus brasiliensis Moenkhaus, 1898: 110, pl. 5, figs 6, 6a–c (♂, Brazil: São Paulo). Mello-Leitão 1918: 95, figs 5–6 (copy of Moenkhaus 1898).
Blechroscelis viridis Mello-Leitão, 1918: 105, figs 19–20 (♂, Brazil: Rio de Janeiro). Mello-Leitão 1947c: 2 (dubious record, see Notes below). Synonymized in Huber 2000: 217.
Mesabolivar brasiliensis: Huber 2000: 217, figs 843–850 (Brazil: São Paulo, Rio de Janeiro, Paraná). Ramalho et al. 2008: 454 (São Paulo). Huber & Rheims 2011: 281 (São Paulo, Rio de Janeiro). Castanheira et al. 2016: 13 (Rio de Janeiro).
Diagnosis. Distinguished from similar congeners (M. kathrinae, M. azureus, M. pallens) by shape of procursus (Figs 274–279; without distal spine-like process; bent rather than evenly curved as in M. azureus; with widened rather than slender tip as in M. kathrinae and M. pallens); from M. kathrinae also by male chelicerae (Huber 2000: fig. 843; distal apophyses in more distal position; presence of indistinct proximal processes) and by epigynum with median pocket (pocket absent in M. kathrinae). Females of M. brasiliensis, M. pallens, and M. azureus may be indistinguishable externally (Figs 292, 294, 298–299).
Type material. Litoporus brasiliensis Moenkhaus, 1898: BRAZIL: São Paulo: ♂ lectotype, 1♀ paralectotype (designated in Huber 2000), MZSP, Poço Grande, “margem do Rio Juquiá” [23.756°S, 46.667°W], i.1898 (W. Moenkhaus), examined (Huber 2000).
Blechroscelis viridis Mello-Leitão, 1918: BRAZIL: Rio de Janeiro: 3♂ syntypes, MNRJ, Pinheiro [22.52°S, 44.00°W], no further data, examined (Huber 2000).
New records. BRAZIL: São Paulo: 2♂ 3♀ 1 juv., ZFMK (Ar 19105), Ubatuba, Fazenda Angelim (23.394°S, 45.063°W), 16–18.xii.2003 (B.A. Huber); 1♂ in pure ethanol, ZFMK (Br03/100-7), same data. 1♂ 1♀, ZFMK (Ar 19106), São Paulo City, Parque Estadual de Cantareira (23.417°S, 46.617°W), 20.xii.2003 (B.A. Huber); 1♂ 1♀ in pure ethanol, ZFMK (Br03/100-16), same data. 5♂ 4♀ in pure ethanol, ZFMK (G002), São Paulo City, Parque Estadual de Cantareira, 28.vi.2001 (R. Pinto da Rocha, C. Rheims).
Rio de Janeiro: 3♂, ZFMK (Ar 19107–08), Reserva Ecológica Rio das Pedras (22°59.5’S, 44°06.0’–06.8’W), 50–200 m a.s.l., 26.ix.2009 (B.A. Huber, A. Giupponi). 3♂ 1♀, ZFMK (Ar 19109), Cachoeira da Pedra Branca near Paraty (23°11.8’S, 44°46.0’W), forest near river, ~ 230 m a.s.l., 22.viii.2007 (B.A. Huber).
Assigned tentatively (see Notes below). BRAZIL: Rio de Janeiro: 4♂ 3♀, ZFMK (Ar 19110), Cachoeiras de Macacu, Reserva Ecológica de Guapiaçú (22°24.4’–25.3’S, 42°44.2’–44.3’W), 140–300 m a.s.l., 25.ix.2009 (B.A. Huber); 3♀, ZFMK (Ar 19111), same locality at 140–280 m a.s.l., 23.ix.2009 (B.A. Huber, A. Giupponi). 1♂ 7♀, ZFMK (Ar 19112), Reserva Ecológica Rio das Pedras (22°59.5’S, 44°06.0’W), 50 m a.s.l., 25.ix.2009 (B.A. Huber); 6♂ 4♀, ZFMK (Ar 19113–14), same locality at 50–200 m a.s.l. (22°59.5’S, 44°06.0’–06.8’W), 26.ix.2009 (B.A. Huber, A. Giupponi); 3♂ in pure ethanol, ZFMK (Br 09-113), same locality, 25–26.ix.2009 (B.A. Huber). 4♂ 3♀, MNRJ (14317), Reserva Ecológica Rio das Pedras (22°59.5’S, 44°06.0’–06.8’W), 50–200 m a.s.l., night, 25.ix.2009 (A. Giupponi, A. Kury); 1♀, MNRJ (14318), same data but day. 4♂ 2♀ 2 juvs, ZFMK (Ar 19115), ~ 3.5 km NW Paraty (23°11.5’S, 44°43.9’W), degraded forest, ~ 50 m a.s.l., 21.viii.2007 (B.A. Huber); 1♂ 1♀ in pure ethanol, ZFMK (Br 07/100-19), same data. 4♂ 1♀ 2 juvs, ZFMK (Ar 19116), Cachoeira da Pedra Branca near Paraty (23°11.8’S, 44°46.0’W), forest near river, ~ 230 m a.s.l., 22.viii.2007 (B.A. Huber). 1♀ in pure ethanol, ZFMK (G005), Itatiaia [22.496°S, 44.561°W], 8–15.vi.2001 (H.F. Japyassú).
Description (amendments; see Huber 2000). Tibia 1 in 32 newly examined males: 8.8–13.1 (mean 11.3); in 30 newly examined females: 6.8–10.4 (mean 8.7). Male femora 2 usually wider than other femora, especially distal thirds. Femora significantly longer than tibiae (e.g., male tibia 1 length 83% of femur 1 length). Prolateral trichobothrium present on tibia 1. Tip of procursus variable, possibly indicating presence of more than one species (Figs 274–279; see Notes below). Proximal processes on male chelicerae sometimes distinct, sometimes barely visible in dissecting microscope. Female femora all about same diameter. Epigynum slightly variable in size and shape, depending on degree of sclerotization of anterior plate and on distinctness of internal ‘valve’ visible through cuticle.
Natural history. The spiders were found in domed webs freely suspended among the vegetation, mostly ~ 0.5– 1 m above the ground. The webs seemed to consist of two sheets: a domed upper sheet where the spider rested (diameter ~ 20 cm), with a tangle of silk lines above the dome, and a lower rather flat sheet slightly below the dome.
Distribution. Widely distributed from eastern Paraná state to Rio de Janeiro state, Brazil (Fig. 731) (but see Notes below).
Notes. As already noted previously (Huber 2000), two species might be included: the ‘true’ M. brasiliensis with a procursus as shown in Figs 274–276 (slender, with distinct dorsal widening), and a possible second species with a procursus as shown in Figs 277–279. The male chelicerae and the epigyna do not seem to differ between these two ‘morphs’ or ‘species’.
‘True’ M. brasiliensis also seem to have a consistently shorter abdomen and shorter legs. Tibia 1 length in ten males of ‘true’ M. brasiliensis: 8.8–11.5 (mean 9.9); in 22 males of the possible second species: 10.8–13.1 (mean 11.8). Tibia 1 length in seven females of ‘true’ M. brasiliensis: 6.8–8.1 (mean 7.6); in 23 females of the possible second species: 8.0–10.4 (mean 9.0).
Geographically, the ‘true’ M. brasiliensis is more southern, the possible second species more northern, but there is considerable overlap in southern Rio de Janeiro state, where both ‘morphs’ or ‘species’ were found to even share localities (Reserva Ecológica Rio das Pedras, Cachoeira da Pedra Branca near Paraty).
The species is not formally split here because I have not (re)examined all material available in collections. Ideally, a much denser sampling combined with molecular species delimitation methods should be done before splitting (or not splitting) this species.
Mello-Leitão (1947c) reported the species (under Blechroscelis viridis) from Minas Gerais, Carmo do Rio Claro. I have not seen his specimens (not specified) but consider the record dubious because of the distance to confirmed records. Ramalho et al. (2008) reported the species from “Estação Ecológica de Boracéia (22°11’S, 48°46’W), Salesópolis” but give wrong coordinates (of the town Boracéia: 22.18°S, 48.77°W; instead of the Ecological Station near Salesópolis: ~23.63°S, 45.83°W).
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 69-71, DOI: 10.11646/zootaxa.4395.1.1, http://zenodo.org/record/1202519