Rideriana amazonica gen. nov. and sp. nov. of Pentatomini (Heteroptera, Pentatomidae) Author Grazia, Jocélia Universidade Federal do Rio Grande do Sul, Instituto de Biociências, Departamento de Zoologia, Prédio 43435. Av. Bento Gonçalves 9500, 91501 - 970. Porto Alegre, RS, Brasil. jocelia@ufrgs.br Author Frey-da-Silva, Angélica Universidade Federal do Rio Grande do Sul, Instituto de Biociências, Departamento de Zoologia, Prédio 43435. Av. Bento Gonçalves 9500, 91501 - 970. Porto Alegre, RS, Brasil. angelzi@zipmail.com.br text Revista Brasileira de Zoologia 2003 2003-09-01 20 3 507 510 journal article 10.1590/S0101-81752003000300023 f8ccd15f-6063-45e2-82ff-6fd9cc63f07f 3583048 Rideriana gen. nov nov. Type species: Rideriana amazonica Grazia & Frey-da-Silva , here described. Dorsal surface of body intense and uniformly punctured; ventral surface of the thorax with more sparse and bigger punctures. Head wider than long. Juga longer than and confluent before tylus; lateral margins of juga slightly emarginate; dorsal surface with transverse furrows. Antennal tubercles with rhomboid lateral spine. Antennal segment I surpassing apex of head, densely punctured; segment II extremely reduced. Relative length of antennal segments: V> III ≈ IV> I> II. Bucculaesubrectilinear, evanescentatbase of head with well developed anterior tooth. Rostrum short, attaining mesosternum. Rostral segment Ishorter than bucculae; segments II and III subequal in length, longer than I and IV. Pronotum subtrapezoidal, anterior 2/3 strongly declivent. Anterolateral margins subrectilinear, scarcely deflected and with angles distinctly toothed; posterolateral margins sinuous. Humeral angles not developed, rounded. Posterior margin subrectilinear. Dorsal surface with scattered yellowish maculae; 1+1 maculae at lateral angles of cicatrices. Prosternum flat between crests limiting this area; mesosternum carinate, anteriorly acute and projected between procoxae; metasternum elevate, anteriorly acute and projected between mesocoxae, posteriorly bifurcate. Ostiolar rugae short, clavate, length 1/4 of evaporatory areas width. Evaporatory areas infuscate, slightly rugose near ostiolum, covering 3/4 of metapleura and almost apical half of mesopleura. Scutellum longer than wide at base; basal angles foveate, apex slightly acute reaching connexival segment VI at middle. Posterior angle of corium subacute, reaching posterior margin of connexival segment VI; posterior margin of corium subrectilinear. Apex of vein Radius with small pale yellow callus followed by dark-castaneous macula. Hemelytra surface with scattered yellowish maculae; membrane infuscate. Femur toothed at limits of apical fourth; tibia dorsally sulcate. Femur and tibia with dark castaneous punctures; tarsi immaculate. Connexivum scarcely exposed. Postero-lateral angles in black tine spines. Abdominal spine extending between metacoxae, apposed to posterior margin of metasternum. Spiracles sided entad by yellowish callus. Trichobothria placed laterad to the imaginary longitudinal line tangential to the spiracles. Abdominal median third, sutures and pseudo-sutures with black maculae; disc with scattered punctures. Figure 1. Habitus. Rideriana amazonica sp. nov. , holotype. Scale: 1 mm . Male. Pygophore quadrangular, posterolateral angles produced posteriorly; dorsal rim (dr) shallowly escavate; ventral rim (vr) escavate with strongly developed hypandrium. Segment X (proctiger) pyriform in dorsal view, apex ventrally directed. Parameres (pa) well developed. Phallus . Basal plate (bp) well developed longer than phallotheca (ph). Phallotheca opened postero-ventrally; postero-lateral angles produced. Processus capitati (pc) wide, almost twice the length of dorsal connective (dc). Vesica (v) well developed, almost twice the length of phallotheca, with processes ventrally projected. Conjunctiva absent. Ductus seminis distalis (dsd) long, twice the length of phallotheca, slightly wider at basal half. Comments. Rideriana gen. nov. has the “facies” of three known genera belonging to Section 3 of ROLSTON et al . (1980) : Serdia , Elsiella Froeschner, 1981 , and Similiserdia . It can be separated from these genera by the extremely reduced second antennal segment, and, at least from Similiserdia and Serdia , by the presence of well-developed hypandrium on ventral rim of pygophore ( Elsiella is known only from females). In Serdia and one of the species of Similiserdia ( S. aciculata ) the antennal segment II is almost equal in length with segment I, and never surpassing 1/3 of III; in Rideriana gen. nov. the antennal segment II corresponds to 1/3 of antennal segment Iand almost 1/9 of segment III. Also Rideriana gen. nov. can be distinguished from Similiserdia by the presence of mesosternal carina, and jugae with lateral margins slightly deflected. In Similiserdia the mesosternum is sulcate and the lateral margins of jugae are not deflected. From Serdia and Elsiella , the new genus can be separated by the antennal segment Isurpassing apex of head; both genera have antennal segment I not, or at least, reaching apex of head. Finally, Rideriana gen. nov. has short rostrum, attaining mesosternum, a character shared with Similiserdia and Serdia ; in Elsiella the rostrum just surpasses the anterior margin of third abdominal sternite. Etymology. The genus is named in honour to Dr. David Rider for his continued effort in cataloguing the pentatomids.