Bibliographic Detail
Cavalier-Smith, T. & Chao, E.E., 2004
Reference:
Cavalier-Smith, T. & Chao, E.E. (2004). Protalveolate phylogeny and systematics and the origins of Sporozoa and
dinoflagellates (phylum Myzozoa nom. nov.). European Journal of Protistology 40(3): 185-212, 7 figures, 2 tables.
Publication Date:
6 September 2004
Abstract:
The protozoan infrakingdom Alveolata comprises the phyla Ciliophora and Miozoa. The name Myzozoasucking
lifeis introduced here to replace Miozoa (protalveolates, dinoflagellates, Sporozoa, apicomonads) as both subphyla
(Dinozoa, Apicomplexa) are commonly or ancestrally myzocytotic feeders. We studied ultrastructurally two
contrasting myzocytotic flagellates: Colpodella tetrahymenae sp. n. (predatory on Tetrahymena), with an inner
membrane complex like Sporozoa, and Voromonas (=Colpodella) pontica gen. et comb. nov., with discrete cortical
alveoli like Dinozoa; we also sequenced 18SrDN A of both of these flagellates and of two highly divergent isolates of
Oxyrrhis. Phylogenetic analysis shows early divergence between Colpodella, Voromonas and Alphamonas edax and
supports the independent origin of dinoflagellates, Perkinsea and Apicomplexa (Sporozoa, Apicomonadea) from
myzocytotic protalveolate flagellates. Oxyrrhis is probably a highly modified dinoflagellate, not a protalveolate with
primitive chromatin and ciliary organization. The rapid basal radiation of Myzozoa is poorly resolved; the predatory
colpodellids sensu stricto are probably sisters of Sporozoa. We discuss early cellular diversification of Myzozoa
(=Miozoa) and revise its classification, establishing a new class Myzomonadea for Voromonas, Alphamonas and
Chilovora (=Bodo) perforans gen. et comb. nov., three new peridinean subclasses (Oxyrrhia, Gonaulacoidia,
Suessioidia), and five new orders: Acrocoelida for Acrocoelus; Voromonadida for Voromonas and Alphamonas;
Chilovorida for Chilovora; Rastromonadida for Rastromonas and Parvilucifera; and Algovorida for Algovora, a new
genus for Colpodella turpis and Colpodella pugnax sensu Simpson and Patterson. We suggest that the flattened inner
membrane complex of Apicomplexa evolved in association with trichocyst loss by fusion of already flattened
myzomonad cortical alveoli as an adaptation for actomyosin-based host penetration and gliding motility.
