Fossil Santanmantis Insect Cretaceous Period, circa 110 million years B.P. A Santanmantis axelrodi fossil insect in matrix. 178 grams, 10 cm (4 in.). Crato formation, near Ceara, Brazil. Acquired 1980s. Old Lincoln collection. The Crato Formation of Brazil is a world-famous site for an incredible diversity of outstanding fossil insects, rare invertebrates including arachnids (spiders and scorpions, centipedes), amazing fish fossils (many preserved in concretions as complete three-dimensional fish), plants and even pterosaurs. [No Reserve]