Living-fossils
Guides
Enicocephalidae
unique-headed bugs, gnat bugs
Enicocephalidae, commonly known as unique-headed bugs or gnat bugs, is a family of approximately 300 species within the ancient and relictual infraorder Enicocephalomorpha. Members are small true bugs, typically around 4 mm in length, characterized by their elongated, constricted heads that give the family its common name. The family exhibits global distribution with greatest species richness in humid tropical and subtropical forests. Enicocephalidae are considered living fossils due to their evolutionarily conserved morphology. The family is classified into about 47 genera placed in five subfamilies, with notable polymorphism including winged males and wingless or short-winged females in many species.
Lymexylidae
ship-timber beetles
Lymexylidae, commonly known as ship-timber beetles, are a family of wood-boring beetles in the suborder Polyphaga. They represent the sole family in the superfamily Lymexyloidea. The family contains over 60 species across four subfamilies and approximately 15 genera, including both extant and fossil taxa dating to the Cretaceous. Many species form obligate symbiotic relationships with ambrosia fungi, which they cultivate and consume rather than feeding directly on wood. Some species are significant economic pests of timber and living trees.