Archostemata

Archostemata is the smallest suborder of beetles. There are less than fifty known species.
Archostemata is an ancient lineage with a number of primitive characteristics. They are similar to the first beetles, which appear in the fossil record about 250 million years ago. The suborder contains the only paedogenic beetles, "Micromalthus debilis".
These beetles are rare. Fossil deposits from the Permian suggest that Archostemata were once much more common and were widespread over the globe. The species which remain are just scattered vestiges of their former population.
"Abundant cladistic and fossil evidence shows the Archostematans are the basal suborder of [true] beetles",