Desmostraca (lit. "bundled shells") is a clade of Diplostoma.
Desmostraca first emerged from the Stenostraca branch around 4187ma, evolving in response to the first Coleostracans. The first Desmostracans were generalist omnivores, but the evolution of Platydonts resulted in many species going extinct, and the surviving species becoming dedicated malacavores.
The defining trait of Desmostracans is their banded shell, which grants them greater protection without impeding their movement. Their top pair of tentacles are antennae lined with scent organs, allowing them to search for food through leaf litter.