Which branchiopod groups are known only from fossils?

Within the class Branchiopoda, there are two orders that are extinct and known only from the fossil record:

• Order Lipostraca: Known exclusively from the Devonian period, this order contains only the fossil species Lepidocaris rhyniensis. It is characterized by having 18 segments behind the head, no carapace, and 13 pairs of trunk limbs in the female.12
• Order Kazacharthra: Appearing in the Early Jurassic epoch, these branchiopods were significantly larger than Lepidocaris. They featured a large carapace covering part of the trunk, a body with more than 40 segments, and six pairs of complex, flattened limbs that projected beyond the carapace.12