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.

Mygalomorph Spider Community of a Natural Reserve in a Hilly System in Central Argentina

“…Other nemesiids, such Stenoterommata spp. in Uruguay and Brazil, also showed sexual activity peaks in the fall and spring ( PérezMiles et al 1993 ; Indicatti et al 2008 ). However, S. platensis on Martin Garcia Island (Argentina) has their reproductive period in summer and fall ( Ferretti et al 2010a ).…”

Spiders (Arachnida: Araneae) in Agricultural Land Use Systems in Subtropical Environments

“…Knowledge of spider diversity in the South of Brazil relies on only a few specific studies, including those of Indicatti et al (2008), Ott (2003), Poeta et al (2010), and Preuss and Lucas (2012), which are nevertheless limited and lack a systemic perspective. Furthermore, these studies do not include environmental variables, which are of paramount importance for understanding the ecological mechanisms of distribution and establishment of spider populations.…”

Climatic Conditions Drive the Abundance and Diversity of Spiders Community in an Atlantic Forest Fragment

“…Inventory studies on spiders diversity and biogeography have fastly improved in the last decades (Nogueira et al 2006, Podgaiski et al 2007, Ricetti & Bonaldo 2008, Rodrigues 2011. However, few studies have been conducted in the Brazilian mixed ombrophilous forest (also known as the Araucaria Forest; Baldissera et al 2004, Baldissera et al 2008, Indicatti et al 2008. The Brazilian mixed ombrophilous forest is considered one the most threatened phytophysiognomy in Brazil (Medeiros 2005), and we must improve our data of spiders abundance and diversity in this phytophysiognomy.…”