This paper presents 20 species of the genus Blaberus (Blaberidae) included in the atropos, brasilianus and giganteus groups. A new group is defined, and 12 new species are described. The genitalia of the eight known species are described. The descriptions are based on the morphology of the head, thorax and abdomen, illustrating the structures of the genitalia and variations in the form of the structures, some within the same species. New records for five known species are discussed. All material is deposited in the collection of the Museu Nacional Resumo: Este trabalho apresenta vinte espécies do gênero Blaberus incluídas nos grupos atropos, brasilianus e giganteus. Um novo grupo é apresentado. Dessas espécies são descritas doze como novas espécies. São descritas as genitálias de oito espécies já conhecidas. As descrições são baseadas em caracteres morfológicos de cabeça, tórax e abdomen com ilustração das estruturas das genitálias e variações na forma de suas estruturas em algumas delas dentro da mesma espécie, bem como novos registros para cinco espécies já conhecidas. Todo o material está depositado na coleção do Museu Nacional do Rio de Janeiro. Palavras-chave: Blattaria, morfologia, diversidade, novo táxon, taxonomia.
Material and MethodsThe specimens were analyzed morphologically according to the usual techniques, as described by Lopes & Oliveira (2000). The terminology of the genital parts, the basic bibliography, and the taxonomic classification are based on the concepts proposed by Roth (1969Roth ( , 1970Roth ( , 1976Roth ( and 2003. The phylogenetic position of the genus follows Kambhampati (1995) and Klass & Meier (2006). After analysis, the plates and the genital parts were placed in microvials containing glycerin and stored with their respective specimens, mounted on insect pins according to the technique developed by Gurney et al. (1964). All material deposited in the collection will be assigned MNRJ catalog numbers. The material can be found in the Blattaria collection of the Museu Nacional.
Results
1) Atropos GroupBlaberus amazonensis sp. nov. Head subtriangular with vertex covered by pronotum; space narrow, measuring about one-sixth of distance between bases of antennal sockets; ocellus large, deflected in relation to the face; antennae long, overreaching base of abdomen.Thorax. Pronotum elliptical, transverse, with lateral tips slightly deflected and apical surface in relief. Developed legs. Cephalic femur with ventro-cephalic margin bearing three robust spines extending from base to near midlength, followed by dense row of small cilia extending to apex, plus robust apical spine; ventro-caudal margin with sparse cilia and robust apical spine; middle and posterior femurs with ventro-cephalic margin bearing sparse cilia plus robust apical spine; ventro-caudal margin with dense row of cilia extending from base to apex, plus robust apical spine. A genicular spine is present; pulvilli on all tarsal articles; nails symmetrical and simple; arolia absent. Tegmen with narrow marginal field, d...