A new species of Goeldia (Araneae: Titanoecidae) with notes on its natural history

Abstract

A new species of Goeldia Keyserling, 1891 is described. Goeldia is the only genus of Titanoecidae with species in the Neotropical region and includes eight species diagnosed by the presence of a patellar process in the male palp. The new species, Goeldia zyngierae sp. nov., was found living inside the Casa de Pedra cave, Ribeira, Itabaiana, Sergipe, Brazil. Goeldia zyngierae sp. nov. is diagnosed by the tegular process with a small constriction near the base of the dorsal part and by a distal narrowing, more visible in the dorsal side of the patellar process of the male palp. The female epigynum shows a pair of sinuous depressions and a large mid field that does not close the copulatory openings as in Goeldia luteipes Keyserling, 1878. The vulva presents a narrow and straight copulatory duct in comparison with those of Goeldia mexicana Pickard-Cambridge, 1896 and a narrow spermathecae. The description includes illustrations of the genital organs, measurements of the body and legs and leg spination. Notes on the natural history show that inside the cave the spiders live farther than the first 40 m, in the aphotic zone, under stones or on the wall. They were never observed alone or walking on the ground, and the webs contained two to thirty spiders of different life stages, living together, suggesting a possible cooperative behavior. Further field work is needed to confirm and understand the degree of sociability of this new species, if this species is restricted to caves, and if this behavior occurs only inside the caves

Convergence on reduced stress behavior in the Mexican blind cavefish

“…Caves throughout the world have similarities with one another, including perpetual darkness, cooler and more consistent water temperatures, and a lack or reduction in the number of primary producers (Poulson and White, 1969). As such, many cave animals have converged on a suite of behavioral modifications such as loss of sleep and altered locomotor rhythms (Duboué and Borowsky, 2012; Duboué et al, 2011; Hervant et al, 2000; Jegla and Poulson, 1968), altered feeding (Dorigo et al, 2017; Kowalko et al, 2013a; Mammola and Isaia, 2017), loss of social behavior (Almeida-Silva et al, 2009; Kowalko et al, 2013b; Yap et al, 2011), and reduced aggression (Elipot et al, 2013; Manenti et al, 2015; Stritih and Kosi, 2017). The functional significance of reduced stress in cavefish is not clear, yet it may be related to the lack of predators in the cave environment.…”

Spiders in caves

“…Documented observations in spiders-mostly anecdotal [27]-primarily refer to reproductive behaviour [13,66,68,72]. Complex courtships were documented in troglophiles [13,68], whereas maternal care was observed in troglobiont Nesticidae [66,73]. Sociality in cave spiders was never documented [14].…”

“…A reduced number of eggs/cocoons (less than 10) was also documented for several troglobionts [28,50,[65][66][67]. For comparison, a number of eggs/eggsacs one order of magnitude higher was documented for troglophile species able to disperse outside the cave habitat [68,69]. Deeleman-Reinhnold [51] provided a comprehensive analysis on this topic focusing on the genus Troglohyphantes, comparing size and number of eggs/eggsacs in 20 regressed and nonregressed species.…”

“…Little is known about the behaviour of subterranean species, as in most cases the rarity of species often precludes anything but sporadic observations. Documented observations in spiders-mostly anecdotal [27]-primarily refer to reproductive behaviour [13,66,68,72]. Complex courtships were documented in troglophiles [13,68], whereas maternal care was observed in troglobiont Nesticidae [66,73].…”

“…Sociality in cave spiders was never documented [14]. Non-territorial 'subsociality', in the form of free movements of the spiders inside and between interconnected webs, was tentatively proposed for Goeldia zyngierae Almeida-Silva, Brescovit & Dias (Titanoecidae), a troglophile inhabiting Brazilian caves [68].…”