Ctenopoda is a suborder of the order Cladocera, comprising the three families Holopediidae, Pseudopenilidae & Sididae. Its members mostly live in fresh water, but Penilia is marine. ...
(from the article `branchiopod`) ...and used in filter feeding; nauplius larvae; fossils known from Cretaceous; recent forms worldwide in temporary fresh waters but not in polar ...