Abstract
The Araneidae is a speciose family including web-spirming spiders that are very abundant in various terrestrial ecosystems. Sixty-five araneid species from 20 genera were collected during an inventory of riparian forests in southem Brazil. Among thesewere one new species, described here as Mangora piratini sp. nov. Also discovered were the previously unknown males of Alpaida citrina (Keyserling, 1893), A. octolobata Levi, 1988 and Testudinaria lemniscata (Simon, 1895), which are described here for the first time. Metazygia floresta Levi, 1995, Ocrepeira malleri Levi, 1993 and Testudinaria quadripunctata Taczanowski, 1879 are recorded for the first time for Rio Grande do Sul State, Brazil.