[1] Later, the same author treated this group as class Perkinsasida within the phylum Apicomplexa, suggesting that Perkinsus is the most primitive apicomplexan.

[11] In 1999, with the discovery of Parvilucifera, biologists Fredrik Norén and Øjvind Moestrup separated the class Perkinsea into a new phylum Perkinsozoa, within the Alveolata, to accommodate these two genera.

[14][15] Apicomplexa Chrompodellids Squirmida Perkinsozoa Dinoflagellata Ciliophora Colponemids Perkinsids are a monophyletic group (or clade) of Alveolata, a large group of ecologically diverse protists such as dinoflagellates, ciliates, apicomplexans and chrompodellids, all characterized by the presence of cortical alveoli below their cell membrane.

[12] Similarly, the genus Acrocoelus, assigned directly to the order Acrocoelida without a family,[17] is also excluded due to the absence of molecular data.

[18] Shown below is the commonly accepted scheme, omitting order-level taxa: 'NAG01' clade Maranthos Pararosarium Xcellia Notoxcellia Gadixcellia Salmoxcellia Cryoxcellia Perkinsus Parvilucifera Snorkelia Dinovorax Tuberlatum As mentioned above, two genera have uncertain placement because they have never been genetically sequenced, but they have been assigned to Perkinsea on the basis of their morphology:[13]