Litter dwelling mygalomorph spiders (Araneae: Microstigmatidae, Nemesiidae) from Araucaria forests in southern Brazil, with the description of five new species

Abstract

Six mygalomorph spiders species belonging to two families, were collected in the Centro de Pesquisa e Conservação da Natureza Pró-Mata, São Francisco de Paula, state of Rio Grande do Sul, Brazil. Five of those species, five are new. Microstigmatidae: Xenonemesia araucaria sp. nov., males differ from those of X. platensis Goloboff, 1988 and X. otti Indicatti, Lucas & Brescovit, 2007 by the curved and very long embolus in the male palp. Females differ from the remaining species of the genus in the seminal receptacle very long and sinuous or twisted. Nemesiidae: Acanthogonatus ericae sp. nov. - males resemble those of A. tacuariensis (Pérez-Miles & Capocasale, 1982) and A. quilocura Goloboff, 1995 by the serrated, curved and long embolus but are distinguished by the presence of a flange on the apex of the embolus. Females differ from the remaining Acanthogonatus by the short copulatory ducts, arising from the apex of the basal dome. Stenoterommata arnolisei sp. nov. is distinguished from the remaining species of the genus by the large sub-apical area of bulb, with a great number of keels, extending to the median region in the male palp and by the long copulatory ducts and spermathecae arising from internal border of basal dome in the female genitalia. S. grimpa sp. nov.: males resemble those of S. arnolisei sp. nov. by the shape of the palpal bulb and by the short embolus, but differ in the keels, restricted to the apical region. Females differ from remaining Stenoterommata by the presence of two spermathecae in the rounded fused basal dome. S. curiy sp. nov.: males resemble those of S. grimpa sp. nov. by the shape of palpal bulb and the very short embolus, but differ by the translucid keels restricted to the larger distal region. The presence of S. palmar Goloboff, 1995 is confirmed for Brazil. Males of S. palmar are distinguished from the remaining species of the genus by the long, slender and slightly distally curved embolus. Females are distinguished by the single spermathecae arising from the basal third or median area of the long and triangular basal dome. All spiders were collected with pitfall trapping at six distinct areas (two Araucaria forest areas, two secondary forests and two Pinus spp. Silvicultural plantations) over a period of 20 months. Abundance data between areas was compared for S. arnolisei sp. nov. and X. araucaria sp. nov. based on the mean catches of spiders in each area. No clear habitat preference was shown for each of the species, suggesting broad habitat tolerances. Phenological data were obtained through the abundance in each trapping period; results suggest an overwintering reproductive pattern for S. arnolisei sp. nov. and a spring-summer pattern for X. araucaria sp. nov.