Protozoa behind animals and fungi: Cavalier-Smith’s 1998 Neomonada chapter
Thomas Cavalier-Smith’s 1998 chapter on the protozoan phylum Neomonada and the origin of animals and fungi appeared in a Systematics Association volume. No open copy is available, so this record draws on how other papers describe the chapter, explains why Wikispecies links to it and follows its groupings into the genome era.
What the study did and found
The record is “Neomonada and the origin of animals and fungi”, a 33-page chapter by Thomas Cavalier-Smith in Evolutionary Relationships Among Protozoa, a 1998 Systematics Association volume edited by Coombs, Vickerman, Sleigh and Warren (Cavalier-Smith, 1998a). Its content is best known from the author’s companion paper of the same year (Cavalier-Smith, 1998b).
That paper places phylum Neomonada in kingdom Protozoa with three subphyla, Apusozoa, Isomita and Choanozoa, and cites the chapter for placing the parasitic Ichthyosporea and the fonticulid social amoebae in Choanozoa (Cavalier-Smith, 1998b). A 2000 paper credits the chapter with proposing the name Ichthyosporea (Fredricks et al., 2000).
Why it is cited
The one referring page recorded here is the Wikispecies page “Protozoa”, which lists the chapter under “Cavalier-Smith (1998a)” among historical classifications of the kingdom and links to this record.
That use is accurate but thin: Neomonada did sit inside kingdom Protozoa in the author’s 1998 system, yet the entry shows nothing of the phylum, its subphyla or the name Ichthyosporea.
In his companion paper the author called Neomonada a broad paraphyletic assemblage, some of whose lineages were closer to a higher kingdom than to one another. His 1998 Apusozoa also held Jakoba and Ebria, which are now placed far from the apusomonads.
By 2002 the author had made Apusozoa a phylum of its own and dropped Neomonada (Cavalier-Smith, 2002). Later molecular studies put apusomonads beside the opisthokonts and supported choanoflagellates as the sister group of animals (Adl et al., 2019).
The topic today
Animals and fungi now sit in Opisthokonta, and the protist specialists’ consensus classification of 2019 uses no formal ranks (Adl et al., 2019). Ichthyosporea is an accepted class with at least 50 described species by a 2024 count (Shabardina et al., 2024).
For the current picture, see our explainer Animals, Fungi and Protozoa: How a 1998 Idea Held Up.