Published online by Cambridge University Press: 31 May 2012
Male and female adults of Paenecalyptonotus fontinalis n. gen., n. sp., are described. This is the second known species of Acalyptonotidae, and is unique in that adults have the idiosomal dorsum nearly covered by a sclerotized plate rather than mostly membranous, have 3 pairs of genital acetabula rather than 7 to 16 pairs, and inhabit cold water seepage areas and springs rather than lakes. Discovery of this species contributes to the elucidation of the relationship of Acalyptonotidae to other Arrenuroidea.