Late Paleozoic insects from the Konservat-Lagerstatte Mangrullo formation, Paraná basin, Uruguay

Abstract

The South American Paleozoic entomofauna is largely diverse, including a rather great number of previously described taxa. However, at the present day, if we compare with the North Hemisphere record and the Triassic entomofauna, the quantitative data available is scarce. More than 35 species have been collected and described as originated from distinct Late Paleozoic sequences: Bajo de Veliz Formation (Upper Carboniferous-Lower Permian, Paganzo Basin, San Luis Province) and Rio Genoa Formation (Lower Permian, Tepuel Genoa Basin, Chubut Province), Argentina; Mangrullo Formation (Upper Carboniferous-Lower Permian, Parana Basin), Uruguay; Iratí/Serra Alta formations (Lower Permian, Paraná Basin, State do Rio Grande do Sul and Sáo Paulo), Río do Rasto Formation (Middle Upper Permian, Paraná Basin, Sáo Paulo State), upper section ?Taciba Formation (Lower Permian), and uppermost Campo Mouráo Formation (Upper Carboniferous-Lower Permian), Itararé Group of the Paraná Basin, Brazil. As mentioned above, in Uruguay, the insects come from the Mangrullo Formation, an ancient Konservat-Lagerstátte of Late Paleozoic age (probably Gzhelian-Asselian), at the Estancia "El Barón" locality, Cerro Largo Department. Until now, three insect species have been formally described, Paracicadopsis mendezalzolai (Hemiptera: Cycadopsyllidae), Perlapsocus formosoi (Perlaria: Perlapsocidae), and Barona arcuata (Blattodea: Incertae sedis). However, other insects have been recently collected from the Mangrullo outcrops and currently are under study: blattids, beetles (? Permocupedidae), glosselytrodeans (Jurinidae), permopsocidans (Psocidiidae), and mecopterans (Permochoristidae). The fossils are housed in the paleontological collection at the Departamento de Paleontología of Facultad de Ciencias-Universidad de la República (UdelaR), Montevideo, Uruguay, under acronym FC-DPI. The insects are represented mainly by isolated forewing impressions and referred mainly to terrestrial and phytophagous groups. The Mangrullo Formation includes a moderately diverse entomofauna similar to Carboniferous-Permian entomofauna from Brazil, Argentina, Russia, France, USA, and China evidencing the influence of the Pangea supercontinent during this time. The Mangrullo insects were recorded in association with mesosaurian skeletons, plants (e.g., left cuticles, stems and reproductive organs, permineralized and probably silicified tree ferns), and pygocephalomorph crustaceans. This community developed in areas at the Mangrullo Lagoon with seasonally colder and arid climate alternating with warmed temperatures and humid climatic conditions typical of the Late Carboniferous-Early Permian times.