ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Accepted by R. Sites: 7 Nov. 2023; published: 22 Nov. 2023 193 Zootaxa 5375 (2): 193–213 https://www.mapress.com/zt/ Copyright © 2023 Magnolia Press Article https://doi.org/10.11646/zootaxa.5375.2.2 http://zoobank.org/urn:lsid:zoobank.org:pub:A8646101-9E84-4BB4-AA68-2DDD27BBD309 Pelocoris Stål, 1876 of northeastern Brazil (Hemiptera: Heteroptera: Naucoridae): first records and a key to the species RENATA SANTOS VIANA 1,6* , CLEILTON L. FRANCO 2,3 , AIALA ALANA P. RAMOS 4,7 , RODOLFO MARIANO 4,8 , CARLOS A. SILVA DE AZEVÊDO 1,5,9 & FABIANO STEFANELLO 5,10 1 Universidade Estadual do Maranhão, Pós-graduação em Biodiversidade, Ambiente e Saúde, Centro de Estudos Superiores de Caxias, Maranhão, Brazil. 2 Universidade Federal Rural do Rio de Janeiro, Programa de Pós-graduação em Biologia Animal, Seropédica, Rio de Janeiro, Brazil. � cleiltonubc@hotmail.com; https://orcid.org/0000-0003-1827-773X 3 Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Entomologia, Rio de Janeiro, Rio de Janeiro, Brazil. 4 Universidade Estadual de Santa Cruz (UESC), Laboratório de Organismos Aquáticos (LOA), Ilhéus, Bahia, Brazil. Laboratório de Organismos Aquáticos, Ilhéus, Bahia. 5 Universidade Estadual do Maranhão, Departamento de Química e Biologia, Laboratório de Entomologia Aquática, Caxias, Maranhão, Brazil. 6 � renathasanthus@gmail.com; https://orcid.org/0000-0002-5465-3125 7 � aialaalana@gmail.com; https://orcid.org/0000-0003-4031-9000 8 � rodolfomls@gmail.com; https://orcid.org/0000-0001-7304-2007 9 � casazevedo08@gmail.com; https://orcid.org/0000-0002-0503-3843 10 � stefanellof@gmail.com; https://orcid.org/0000-0002-9622-8311 *Corresponding author Abstract Naucoridae is a family of aquatic bugs, distributed in tropical and subtropical regions of the world, and comprises 437 species, 47 genera, and eight subfamilies. Five subfamilies, 10 genera and 68 species have been recorded from Brazil. Pelocoris Stål is a genus exclusive to the New World, with 14 species described; eight species and two subspecies have been recorded from Brazil. For the northeastern region, there are no records of occurrence for any species in this genus. The objective of this work was to survey the fauna of Pelocoris in the northeastern region and map the distribution of the species. We examined 180 specimens belonging to six species: Pelocoris binotulatus nigriculus Berg, 1879, P. bipunctulus (Herrich-Schäffer, 1853), P. magister Montandon, 1898, P. poeyi (Guérin-Méneville, 1835), P. politus Montandon, 1897, and P. subflavus Montandon, 1898. This work contributes directly to reducing the Wallacean and Linnean gaps in Naucoridae diversity for northeastern Brazil and highlights the diversity in the region, which is still poorly studied and poorly known. Key words: Aquatic insects, geographical distribution, morphology, saucer bugs, taxonomy Introduction Naucoridae (Insecta: Hemiptera: Heteroptera) is the most diverse family of Nepomorpha in terms of genera and the third in number of species (Polhemus & Polhemus 2008). Naucoridae is divided into eight subfamilies, 47 genera and 437 species are distributed worldwide (Sites 2022; Sites & Bergsten 2022). The fauna of aquatic bugs from Brazil is poorly known in most of the country. So far, 10 genera and 68 species of Naucoridae have been recorded from Brazil, with species records concentrated in the southeastern, especially in Minas Gerais and Rio de Janeiro states, and northern regions, mainly in Pará and Amazonas states (Moreira et al. 2011; Ribeiro et al. 2023). The genus Pelocoris is a New World genus with 14 species (Nieser 1969; Davis 1986; Manzano et al. 1995; Polhemus & Sites 1995; Reynoso-Velasco & Sites 2021). Only eight species and two subspecies have been recorded from Brazil (Moreira et al. 2011; Ribeiro et al. 2023): Pelocoris binotulatus (Stål, 1860) [P. binotulatus binotulatus