The oldest definitive ant fossil, a 113-million-year-old "hell ant" (Vulcanidris cratensis), has been discovered in northeastern Brazil. This remarkable find, preserved in limestone, pushes back the known fossil record of ants and provides insights into early ant evolution. The discovery highlights the importance of examining existing collections and sheds light on Brazilian paleontology.
Hell Ant Discovery
The newly identified hell ant, belonging to the extinct subfamily Haidomyrmecinae, existed during the Cretaceous period. These ants are characterized by their unique, scythe-like mandibles, which they likely used to capture and impale prey. Unlike modern ants, hell ants had jaws that moved vertically. The fossil represents the first hell ant discovered in rock, rather than amber, suggesting a wider distribution than previously known.
Dirt Ant Evolution
In related news, scientists have uncovered a 16-million-year-old dirt ant fossil (Basiceros enana sp. nov.) in Dominican amber. This discovery challenges previous assumptions about dirt ant evolution, indicating that these ants evolved to be larger, not smaller. The ancient dirt ant, though smaller than its modern counterparts, already possessed the specialized hairs used for camouflage.
Modern dirt ants can grow up to 9 millimeters in length, while the fossil ant measured just 5.13 millimeters. This suggests a trend towards increasing body size over millions of years. Despite their adaptations, Basiceros enana disappeared from the Caribbean around 5.3 million years ago, likely due to ecological changes.