Menemerus nigli Wesolowska & Freudenschuss 2012
Creators: name: Mariante, Rafael M.
name: Hill, David E.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Salticidae
Menemerus
Menemerus nigli

description: The adult male Menemerus nigli
(Figures 3-9, 18)
is similar to the female in color, but has a conspicuous fringe of white setae directed ventromedially on the medial side of each paturon. This fringe is also found on adult male M. bivittatus, also found in Brazil (Figure 22). Unlike the male M. bivittatus, the male M. nigli does not have a more-or-less linear tract of scales on the midline of the opisthosoma, but like the female has a more variegated pattern of scales on the dorsal opisthosoma that usually includes chevons toward the rear. The white clypeal band of the male M. bivittatus is also much wider than that of M. nigli. The dorsal cymbium of the pedipalp of M. nigli is covered with long off-white setae. In M. bivittatus the dorsal cymbium is dark brown.
The pedipalp of the adult male Menemerus nigli has a relatively long cymbium and a large, curved embolus to the medial side of a prominent, sclerotized ventromedial lobe of the tegulum situated over the spermaphore loop (Figure 9). Unlike some Menemerus, the embolus has a single (not bifurcated) apex.
Many of the photographs of M. fulvus (L. Koch 1878) that have been posted on the internet (e.g., iNaturalist 2020), all from south and southeast Asia, may actually represent M. nigli. Unfortunately more recent drawings of the pedipalp of that species (e.g., Bohdanowitz & Prószyński 1987) bear little resemblance to the drawing presented with the original description (L. Koch 1878). As noted by Wesołowska in her revision of the African Menemerus (1999), "the majority of species (except few widely distributed) are very poorly known, the descriptions in older publications are inadequate and not supplemented with figures. Numerous specimens in museum collections are misidentified or unidentified." Presently a revision of Menemerus that includes the Asiatic species is needed.
alcohol.
Penultimate males (Figure 10) were similar to adult females but darker in appearance with fewer lightcolored setae, but identifiable as males by the presence of club-shaped cymbium at the end of each pedipalp. They lacked the white setae on the medial side of each paturon as found in the adult male.
Adult female Menemerus nigli (Figures 11-18) were similar to penultimate in coloration, with shiny black chelicerae and lacking the white setae found on the medial side of each paturon of the adult male. Like males they have a band of white to off-white scales across the clypeus. In comparison, adult female M. bivittatus (Figure 23) have a solid cover of orange setae around the front eyes and covering the clypeus. Compared to M. bivittatus, adult female M. nigli have a more variegated (light or dark brown) rather than light brown array of dark setae on the dorsal opisthosoma, and lack dark lateral bands around the opisthosoma. The pedipalps of M. bivittatus females are also lighter in color rather than brown, with a more complete cover of white to off-white setae.
The epigynum of M. nigli, with wide atria open toward the front and a pair of posterior spermathecae (Figure 17), was first described by Ali et al. (2018).
Our study sites (1.1 and 1.2, located 260 meters apart from each other) where Menemerus nigli was found in Rio de Janeiro are shown in Figures 19-20. Another observer found Menemerus nigli at a third site (site 2), 2.4 km apart from our sites (Figures 2, 21). Previously, in Asia, this species was found either on or under stones, or on an indoor wall (Wesołowska & Freudenschuss 2012; Chatterjee et al. 2017; Seyfulina et al. 2020). In Rio de Janeiro it was found only in a synanthropic context, living on the same kind of painted concrete or stucco exterior walls where the cosmopolitan M. bivittatus (Figures 20, 22-23) is often found. Previously, we reported the occurrence of the African salticid Thyene coccineovittata in a synanthropic context, but living on garden plants in Rio de Janeiro and nearby areas (Mariante & Hill 2019). These observations support the view that species that can adapt to anthropogenic habitats may be more successful in finding a niche when introduced to a remote place.
Intercontinental spider introductions are now taking place at high rate as a result of international trade (Kobelt & Nentwig 2008). Introduced spiders are also known to displace native species (Jakob et al. 2011; Houser et al. 2014). Each major biogeographical province has its own distinct fauna of salticid groups, and some of these may be the result of single-species introductions many millions of years ago. For example, the subtribe Freyina is an endemic Neotropical salticid clade (Edwards 2015; Maddison 2015) that may have evolved from a single species of Afrotropical origin, just as the caviomorph rodents of South America represent a monophyletic group that evolved from a single introduction from Africa (Lessa et al. 2014). A single introduction could greatly alter the neotropical fauna of the future.
description: Published as part of Mariante, Rafael M. & Hill, David E., 2020, First report of the Asian jumping spider Menemerus nigli (Araneae: Salticidae: Chrysillini) in Brazil, pp. 1-21 in Peckhamia 205 (1) on pages 1-15, DOI: 10.5281/zenodo.3875200