Rhigus

Abstract: The Neotropical entimine weevil genus Rhigus Schoenherr, 1823, one of eight genera belonging to the tribe Entimini Schoenherr, 1823 (AlonsoZarazaga and Lyal 1999; Vanin and Gaiger 2005), presently consists of 13 recognized uniquely South American species (Gaiger 2001). All but one of these species are distributed in the Atlantic forest biotopes of eastern (and especially southeastern) Brazil, Argentina, and Paraguay (Alonso-Zarazaga and Lyal 1999; Blackwelder 1947; Gaiger 2001), although two of these also occur in the Caatinga and Cerrado habitats of northeastern and southern Brazil (Gaiger 2001). The single remaining species, Rhigus speciosus (Linnaeus, 1758), is a denizen of tropical forest biotopes in the Amazon basin, where it is widely recorded from Brazil (states of Acre, Amapá, Amazonas, Mato Grosso, Pará, and Rondônia) (Gaiger 2001), French Guiana (Wibmer and O’Brien 1986), and, recently, Colombia (departments of Amazonas and Tolima) (Girón and Cardona-Duque 2018). During recent fieldwork conducted by the authors and their students and associates during a tropical ecology field course in the Peruvian Department of Madre deDios, a single specimen ofR. speciosuswas found, revealing for the first time the presence of both the genus Rhigus and that species in Peru. The specimen was identified using the keys in Vaurie (1951) and Gaiger (2001), closely matching the characters and descriptions given in those keys. One specimen: Peru, Madre de Dios, c. 20 km northeast of PuertoMaldonado, 12.4519°, 69.0795°, c. 250 m elevation, 14.iv.2019, on low roadside vegetation (plant species not noted) in secondary lowland tropical rainforest. The Peruvian locality is a new country record for the genus and species. It fits within the Amazonian subregion distribution pattern for Neotropical Entimini as defined through the generalized track analysis of the tribe by Romo and Morone (2011). The Peruvian locality (Fig. 1) represents both the most westerly and (marginally) the most southerly known distributional limits for the species, with the closest previously recorded locality being Tarauacá in the Brazilian state of Acre, approximately 510 km to the northwest. While the presence of R. speciosus (Figs. 2–3) in Peru is unsurprising given its very wide distribution across lowland Amazonia, formally recording it represents a small contribution towards documenting the incredible insect biodiversity of that megadiverse country.