New insect records from La Cantera Formation (Lower Cretaceous), San Luis Province, mid-western Argentina

LARA, M.B.; SIERRA, MELINA; ARCUCCI, ANDREA; MANCUSO, ADRIANA C.

Buenos Aires

Congreso; XII Congreso de la Asociación Paleontológica Argentina; 2021

APA

The Cretaceous Period was a significant stage for the history of insects given that the climatic, environmental, and floristic changes provided new available ecological niches across many habitats that strongly influenced the evolution of the group. The Lower Cretaceous La Cantera Formation (El Gigante Group, San Luis Basin), San Luis province, in central-western Argentina, includes an abundant and diverse biota characterized by mixed terrestrial and freshwater components (e.g., plants, palynomorphs, fishes, insects, spinicaudatans, ostracods) in an excellent state of preservation. From the type section, we report here new fossil insects and the first occurrences of Reduviidae, Cicadellidae (Hemiptera), and putative Histeroidea (Coleoptera). The described materials, housed at the Museo Interactivo de Ciencias (MIC), Universidad Nacional de San Luis (UNSL), comprise impressions of complete insect bodies with some delicate structures preserved (e.g., antennae, legs, setae, eyes, mouthparts, etc.). These new records, along with previously described endemic aquatic heteropterans (e.g., notonectids, corixids) collected from the studied area illustrate the occurrence of a modern entomofauna in the La Cantera Formation integrated by aquatic and terrestrial insects represented by adult and immature stages. The entomofauna inhabited lakes developed in fluvial floodplains (as autochthonous elements) or in association to terrestrial vegetation (e.g., pteridophytes, equisetaleans, gnetophytes, and angiosperms) that grew close to a lacustrine environment (as allochthonous elements) under warm and arid climatic conditions during the Early Cretaceous. Despite the fact that the La Cantera Formation does not contain spectacular fossil insects compared to those recorded in well-known coetaneousdeposits worldwide (e.g., Crato Formation), these new findings are important because they enrich our knowledge about entomological associations and ecological roles that insects played within Early Cretaceous environments, during an important evolution time of the angiosperms.