Accepted by K. Williams: 21 Jun. 2018; published: 3 Aug. 2018 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2018 Magnolia Press Zootaxa 4455 (3): 499–512 http://www.mapress.com/j/zt/ Article 499 https://doi.org/10.11646/zootaxa.4455.3.6 http://zoobank.org/urn:lsid:zoobank.org:pub:60763C18-3E38-452C-9019-F16863B3106D A revision of the Neotropical eumenine wasp genus Stenosigma Giordani Soika, 1978 (Hymenoptera, Vespidae) WELLINGTON D. FERREIRA 1,2 , LETÍCIA A. DE OLIVEIRA 1 & MARCEL G. HERMES 1 1 Laboratório de Sistemática e Biologia de Insetos, Departamento de Biologia, Universidade Federal de Lavras, Caixa Postal 3037, Lavras, Brasil, 37200-000 2 Corresponding author. E-mail: wellingtondonizet@hotmail.com Abstract The Neotropical eumenine wasp genus Stenosigma Giordani Soika, 1978 is revised. Stenosigma mariae Ferreira & Hermes sp. nov. and S. panamensis Ferreira & Hermes sp. nov. are proposed as new. An updated identification key for species, new distributional records, and additional information on the species currently recognized within the genus are presented. Key words: Eumeninae, potter wasps, taxonomy Introduction Stenosigma Giordani Soika, 1978 is a small genus of Neotropical eumenine wasps, currently containing five recognized species (Giordani Soika, 1978; Hermes & Ferreira, 2016). The group belongs to the tribe Eumenini sensu Hermes et al. (2014) and is closely related to Pararhaphidoglossa von Schulthess, sharing with species of the latter a conspicuous pretegular carina and the lower posterior portion of the propodeum with a projecting apical lamella. Species of Stenosigma resemble those included in the genus Pachymenes de Saussure in shape, size, and coloration. For this reason, some species were originally described within Pachymenes, being transferred later when Giordani Soika (1978) recognized discrete morphological properties that led him to describe the group as a taxon of its own. Species of Stenosigma may be readily identified by the following combination of characters: first metasomal tergum petiolate, mid tibia with one apical spur, lateral pronotal carina present throughout the entire pronotal extension, mesosoma with pretegular carina, and preapical portion of the first metasomal tergum not thickened and with a well-developed fossa (Carpenter & Garcete-Barrett, 2003). The study of Hermes et al. (2014) included only two species of Stenosigma, recovering the group as monophyletic. Nevertheless, the combination of attributes mentioned above, especially the conformation of the first metasomal tergum, is unique among the Neotropical Eumeninae, probably being strong evidence for the group monophyly. We present a taxonomic revision of Stenosigma, including the description of two new species, distributional information, and an illustrated key to all species currently recognized within the group. Material and methods Material from the following institutions was examined: AMNH, American Museum of Natural History (New York, USA—Dr. James M. Carpenter); NHM, Natural History Museum (London, England—Dr. Gavin Broad); CMNH, Carnegie Museum of Natural History (Pittsburgh, USA—Dr. John Rawlins); ZMHB, Museum für Naturkunde (Berlin, Germany—Dr. Frank Koch); MNHN, Muséum National d’Histoire Naturelle (Paris, France—Dr. Claire