Agnostoidea

Agnostidae is a family of Agnostida trilobites. Like all Agnostina, they were eyeless and had only two thoracic segments. These trilobites inhabited benthic waters worldwide from 508 to 461 million years ago. The family includes the following genera, among others:

Geragnostus is a genus of very small agnostid trilobites whose fossils are found Ordovician-aged marine strata from Eurasia, North America and Argentina.