Oligocene
Guides
Cryptorhynchina
hidden-snout weevils
Cryptorhynchina is a subtribe of weevils within the subfamily Cryptorhynchinae, commonly known as hidden-snout weevils. The group has gained scientific attention through fossil evidence showing that at least one extinct species within this lineage served as an orchid pollinator approximately 20–45 million years ago. No present-day members of this subtribe have been documented carrying orchid pollinaria, though this absence may reflect their secretive behavior rather than lack of ecological interaction.
Hygrotini
Hygrotini is a tribe of small diving beetles in the subfamily Hydroporinae. The tribe contains approximately 137 species, most of which inhabit freshwater environments. Multiple lineages have independently evolved tolerance to saline and hypersaline conditions, with some species surviving in concentrations more than double that of seawater.
Sessilia
acorn barnacles, sessile barnacles
Sessilia is an order of barnacles (Cirripedia) characterized by the absence of a stalk (peduncle), with the body attached directly to the substrate by a calcified base. The group comprises two orders: Verrucomorpha (two families) and Balanomorpha (14 families). Sessilia is considered monophyletic and likely derived from stalked ancestors. The Australasian region preserves the earliest stratigraphic records for several families including Pachylasmatidae, Tetraclitidae, Archaeobalanidae, and Verrucidae.