A reassessment of the type-materials of Ostracoda (Crustacea, Oligostraca) lost in the “Museu Nacional” Great Fire of September 2, 2018

On September 2, 2018, a catastrophic fire occurred at the “Museu Nacional” in Rio de Janeiro, Brazil, nearly destroying its once rich scientific collections. That accident latter generated a movement from the museum and the scientific community to restore their collections, either by bringing new specimens to the institution or by providing information about the ones lost in the tragedy. Herein we present our contribution to that effort: high-resolution scanning electron microscope images of holotypes and paratypes of 23 fossil ostracod species and subspecies that were destroyed by the “Museu Nacional” fire. These taxa occur in several Brazilian and central West African Lower Cretaceous lithological units, and some of them (Cypridea [Pseudocypridina] faveolata and Sebastianites fida minor) are even guide fossils to these strata. The present images and taxonomical updates of species – including new combinations for Sebastianites fida minor, Sebastianites? minima, Sebastianites? sostensis granulata and Theriosynoecum ventrostriatum – will also enable future studies of ostracod species from Brazilian and central West African Lower Cretaceous basins, as they provide an accurate system of identification in absence of direct observation of these type specimens once housed at the “Museu Nacional” scientific collections.