The Crato Formation palaeoentomofauna from the Lower Cretaceous (Aptian) of northeast Brazil is extremely well preserved. Crato insects are often complete with abdomen, thorax, head, legs, wings articulated and fragile cuticle details observed at the macro and micro scale. The Crato Formation stands out for the high diversity of fossil insects with at least 386 described species, so far. We investigate the preservation pathways through SEM-EDS and Raman spectroscopy, which give fundamental insights regarding the understanding of this complex theme. Our study compared cuticle soft-tissue preservation of Ensifera in different layers of the Crato limestone. The results of our analyses confirmed that the anaerobic bacterial respiration processes influenced the labile-tissues preservation. Ensifera fossils display preservational stages ranging from kerogenization to pyritization. Kerogenization represents the partial or complete chemical transformation of organic material into aliphatic and cyclic hydrocarbons in situ during mesodiagenesis, while pyritization occurs during the decaying of carcass in the early diagenesis. Here, we followed the previous hypothesis of fish tissue preservation that these processes are governed principally by variations in the positioning and residence time of the carcasses in different microbial zones within the sediment column. Besides early/mesodiagenetic modifications, oxidation processes during recent weathering led to some mineral transformations that played a key role in the preservation of Ensifera.

A new specimen of a stick grasshopper (Orthoptera: Proscopioidea: Proscopiidae) is described from the Early Cretaceous (Late Aptian -Early Albian) Crato Formation of southern Ceará, northeastern Brazil. This is only the second formal description of Proscopiidae in the fossil Record. Unfortunately, LP/UFC CRT 2698 is poorly preserved as a faint impression due to post-diagenetic processes. However, the discovery of this new taxon enhances the diversity of Proscopiidae in the Gondwana, and it confirms the South America as a dispersion zone for this family.

The first representative of the genus Mastotermes Froggatt, 1897 from the Cenozoic of the South America is described here based on seven specimens from the Fonseca Formation, Eocene-Oligocene boundary, Minas Gerais State, southeastern Brazil. Today, Mastotermes is geographically restricted to northern Australia, with only one relict species, Mastotermes darwiniensis Froggatt, 1897. However, its fossil record clearly shows a global distribution, with species ranging from the Cretaceous of Myanmar, Russia, Mongolia and China, throughout Cenozoic of mainland Europe and Miocene of Africa, Mesoamerica and the Caribbean. Along with Spagotermes costalimai Emerson, 1965, Mastotermes brasiliensis sp. n. is the second fossil termite recorded in the Fonseca strata. This discovery extends the paleo-distribution of this genus into Neotropical South America during the Paleogene.

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