Phosphatocopina

The phosphatized bivalved carapace covered the entire body. Members typically grew to a maximum of in length, though Cyclotron grew up to . The earliest larval stages of phosphatocopines are known as "head larva", due to them only having the four pairs of cephalic appendages, a feature that is a shared groundplan with most other arthropod groups. == Ecology ==

Phosphatocopines are generally thought to have been nektobenthic (swimming close to the sediment), and have been suggested to have fed on small particulate organic matter, using the endites and spines on their limbs to trap particles. They are thought to have been tolerant of hypoxic environments, which was probably their preferred habitat. == Taxonomy ==

When phosphatocopines were first described, they were suggested to be ostracods, but this was rejected after their soft tissue was described. They have often been suggested to be close relatives of crustaceans, with the proposed clade containing the two groups dubbed Labrophora. However, their mandibles and maxillae are not strongly morphologically differentiated from the other trunk limbs, with differentiated mandibles and maxillae characterising most crown-group mandibulates, including crustaceans, and as such have been alternatively suggested to be stem-group mandibulates. The fact that specimens with preserved soft tissue all appear to be larval instars makes their exact placement uncertain. Several subgroups have been proposed, such as Hesslandonidae and Vestrogothiidae. Genera • Hesslandona Orsten, Sweden, China Upper Cambrian (Furongian) • Trapezilites Orsten, Sweden, Upper Cambrian (Furongian) • Cyclotron England, Poland, Upper Cambrian (Furongian) • Waldoria Orsten, Sweden, Upper Cambrian (Furongian) • Veldotron Orsten, Sweden, Upper Cambrian (Furongian) • Klausmuelleria Comley Limestone, England, Cambrian Series 2 • Vestrogothia Orsten, Sweden, China Upper Cambrian (Furongian) • Falites Orsten, Sweden, Upper Cambrian (Furongian) • Dabashanella China, Cambrian Stage 3 • Comleyopsis Comley limestone, England, Cambrian Series 2 • Bidimorpha Sweden, Denmark, Middle Cambrian == References ==