New South American Cenozoic records of osteophagus insects: New ichnotaxa and paleoecological implications for the Paleogene and Quaternary of South America

Bioerosions by insects on fossil skeletal remains reveal interactions between these organisms and past faunas. Here, we present the first records of bioerosion by insects in metatherian dentaries from the Itaboraí Basin (upper Paleocene-lower Eocene), southeastern Brazil, and in megafaunal postcranial remains from Pleistocene natural tank deposits in the Northeastern Brazil. Four new ichnotaxa: Asteroichnus radialis igen. et isp. nov. and Maiandroichnus igen. et isp. nov., with three identified ichnospecies, Maiandroichnus titanicus isp. nov., M. osteophagus isp. nov., and M. depressus isp. nov., are described. These ichnotaxa were likely made by colonial insects (termites and ants), with A. radialis attributed to mound-building termites. These findings represent the first indirect evidence on bone substrate of termites during the early Paleogene of Brazil, indicating that these animals occupied an important scavenging role in South America since the late Paleocene-early Eocene. In addition, the Late Pleistocene findings expand the occurrence of bioerosions made by insects in the Brazilian Intertropical Region, with Maiandroichnus nov. suggesting the exploitation of megafauna carcasses by termites or ants.