Vagabond but elusive: two newcomers to the Eastern Amazon (Araneae: Cithaeronidae; Prodidomidae).

The spider clade Gnaphosoidea gathers dionychans with obliquely angled posterior median eyes with flat lenses (Platnick, 1990), which would be part of a compass mechanism rather than being used to form images (Dacke et al., 2001). Besides the Gnaphosidae Pocock, by far the most diverse family of the group (with over 2,000 species), the clade includes six other spider families, mostly recorded from Australia and Africa, such as Ammoxenidae Simon, Lamponidae Simon, Gallieniellidae Millot (with a single species from South America) and Trochanteriidae Karsch (also in Asia and two genera in South America) (Platnick, 1990; 2013). The remaining two families, Cithaeronidae Simon and Prodidomidae Simon, represent the least and the second richest gnaphosoid families, respectively. Cithaeronids are fast-moving nocturnal spiders that hunt actively on the ground. The family comprises two genera and seven species originally from Members of the family resemble those of Ammoxenidae, Gallieniellidae and Trochanteriidae for still having the distal article of the anterior lateral spinnerets (Platnick, 2002). Among these, cithaeronids can be recognized by the long legs with pseudosegmented tarsi (Platnick 1991: fig. 7; Fig. 3 hereof). This character also evolved in Ammoxenus Simon (Ammoxenidae), but this genus can be distinguished from cithaeronids by the reduced female palpal claw (Platnick, 2002). These were found wandering on inside walls of the Institute of Biological Sciences building at the Federal University of Pará (ICB-UFPA) and in the first author's apartment, in downtown Belém. This is the second record of Cithaeron praedonius from the Neotropics, but the species has already been reported from many places around the world, The presence of this species in the Amazon is clearly a case of accidental introduction. Our second record of introduction in the Eastern Amazon concerns the Prodidomidae. The family is widespread, occurring in all continents, except Antarctica, and is the second largest gnaphosoid family, with over 300 species, most Along with Gnaphosidae and Lamponidae, Prodidomidae can be recognized by the loss of the distal article of the anterior lateral spinnerets (Platnick, 2002). They differ from lamponids and gnaphosids by having greatly elongated piriform gland spigots (Platnick et al. 2005; see Figs 9, 11 hereof). Of the 31 genera proposed for the family, about 11 have been reported from the Neotropics, mainly from Chile. (Figs 9–15) from several localities in Brazil, with adults apparently present throughout the year: Salvador (Bahia), Manaus (Amazonas) and Aracajú (Sergipe, coordinates published do not match).