New species, new combinations, and morphological notes of South American Ambrysinae (Heteroptera: Naucoridae)

Although recent studies have been published on Ambrysinae (Naucoridae) from the Neotropical region, few efforts have been made to improve the taxonomic knowledge of this subfamily in Brazil. Two genera of Ambrysinae containing the greatest number of species in South America were recently established to accommodate species previously classified as Ambrysus Stål: Australambrysus Reynoso & Sites and Maculambrysus Reynoso & Sites. The subgeneric classification of Ambrysus has also changed, including the elevation of Melloiella De Carlo back to full generic status. In the present study, three new species of Ambrysinae from Brazil are described, two belonging to Australambrysus and one to Maculambrysus: Australambrysus minutus n. sp., A. tuberculatus n. sp., and Maculambrysus transversus n. sp. In addition, morphological notes are provided for Australambrysus planus (La Rivers) and A. partridgei (De Carlo), the placement of A. fraternus (Montandon) is confirmed, and the following new combinations are proposed: Maculambrysus attenuatus (Montandon) n. comb., and Maculambrysus obscuratus (Montandon) n. comb., species that are transferred from the genus Australambrysus and Ambrysus, respectively. Two of the species treated here (A. fraternus and A. tuberculatus) are included in the Australambrysus plax (La Rivers) species complex, and a morphological redefinition of the complex is presented. Also, the macropterous form and male genitalia of Melloiella truncaticollis De Carlo are described, including new records from southern Brazil.