protoctistn.adj.
/prəʊˈtɒktɪst/, U.S. /proʊˈtɑktəst/ Biology.
A. n.
An organism of the kingdom Protoctista; a eukaryote which is not an animal or a plant (or, in most schemes, a fungus).
ΚΠ
1968 L. Margulis in Science 6 Sept. 1021/2 (figure) Kingdom 2. Protoctists.
1983 Paleobiology 9 204 Siliceous skeletons, developed by some sponges and, later, protoctists.
1991 New Scientist 23 Mar. 49/3 If an organism is neither animal nor plant nor fungus, yet has more than one membrane-bound genome, it is a protoctist.
2004 H. J. Morowitz Emergence of Everything xvi. 107 There is clearly a complex evolutionary pathway from the ancestral protoctist to the coelenterates.
B. adj.
Of or relating to the Protoctista.
ΚΠ
1969 Science 10 Jan. 157/1 True fungi and slime molds are not best treated as two phyla, their designation as such is in part a consequence of the effort to treat these groups within the plant or the protoctist kingdom.
1989 L. Margulis in L. Margulis et al. Handbk. Protoctista p. ix We consider the ultrastructure and sexual patterns of the cytoplasmic (heterotrophic) components of protoctist cells of paramount importance for determination of phyla, classes and the other higher taxa.
2000 Q. Rev. Biol. 75 423/2 Karyomastigont MTOCs [= microtubule organizing centres] were replaced by newly evolved structures such as those described here in protoctist, animal, plant, and fungal cells.
This is a new entry (OED Third Edition, September 2007; most recently modified version published online March 2022).
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n.adj.1968