Ichnofossils attributed to phytophagous arthropods in silicified wood of Missão velha formation, upper Jurassic - Lower Cretaceous, Araripe Basin, Brazil

• Grant number: 18/05824-5
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2018
• Effective date (End): October 31, 2019
• Field of knowledge: Biological Sciences - Zoology - Paleozoology
• Principal Investigator: Marcelo Adorna Fernandes
• Grantee: Viviane Querollaine Pires Turman
• Home Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The Missao Velha Formation, Araripe Basin, Upper Jurassic - Lower Cretaceous, is notorious for the occurrence of silicified fossil trees, which indicates the possibility of the region having supported forests of gymnosperms. Some of these fossilized woods allowed the inference of phytophagic activity in conifers during the period, because perforations and other damages were found with morphological patterns typical of the activity of arthropods in the silicified wood. These structures are simple, a few millimeters wide and were therefore attributed to termites as the main producers. However, drillings different from those previously reported were identified in samples of mineralized wood of the same geological formation. From the observation and comparison of these structures with other current excavations, it is possible to suggest a second group of phytophagous arthropods as responsible for injuries. In these perforations tunnels and galleries, with structural complexities similar to characteristic patterns, maybe resulting from the behavior of numerous insect families. However, the great diversity of Insecta makes it difficult to infer a genus or even a species, relying solely on the observation of its fossil traces. Therefore, a more in-depth study is necessary to make it possible to describe the ichnofossil, as well as the identification of the producer organism, since there are no somatofossils of insects in the Missao Velha Formation. Thereby, it will be possible to increase the knowledge about the entomologycal diversity and the ecological relations in the Brazilian northeast, at the transition from the Jurassic to the Cretaceous period.