An article published in the “Journal of Systematic PalaeontologyJournal of Systematic Palaeontology” reports a study of Helmetia expansa, a species of arthropod that lived about 505 million years ago, in the Middle Cambrian period. Sarah Losso, Jean-Bernard Caron, and Javier Ortega-Hernández examined the fossils discovered over the years in the famous Burgess Shale site for a total of 36 specimens comparing them with species considered close relatives of Helmetia expansa, as they’re included in the Conciliterga group. Over a century after the discovery of the first fossils, this is the first real description of these arthropods that were probably quite close relatives of trilobites.