protostomen.adj.
/ˈprəʊtə(ʊ)stəʊm/, U.S. /ˈproʊdəˌstoʊm/ Zoology.
A. n.† 1. = protostoma n. at proto- comb. form 2a. Obsolete. rare.
ΚΠ
1884 Amer. Naturalist 18 81 Just as the umbilicus is the remnant of the protostome or primordial mouth, so the pineal body and its connections are the remnant in the vertebrate of the neurally situated mouth of the arthropod or mollusk.
2. An animal belonging to any of the phyla in which the mouth is typically derived during development from the embryonic blastopore or primary opening of the gastrula. Contrasted with deuterostome.The protostomes comprise most invertebrates with a more complex organization than coelenterates, including molluscs, arthropods, and most kinds of worm (but excluding echinoderms and chordates). Formerly they were often grouped together under the name Protostomia.
ΘΚΠ
the world > animals > invertebrates > [noun] > specific groups of
Mollusca1661
Acrita1823
microzoon1859
microzoary1863
malacozoic series1877
protostome1958
acoelomate1964
protostomian1968
1958 G. Moment Gen. Zool. 226/1 The protostomes are an immense group divided into many important phyla.
1974 Systematic Zool. 23 494/1 The three lophophorate phyla..superficially appear to bridge the gap between the protostomes and the deuterostomes.
2003 A. Ménez Subtle Beast vi. 53 (caption) Protostomes have ventral nerve cords whereas deuterostomes often have a dorsal neural tube.
B. adj.
Of, relating to, or characteristic of protostomes.
ΚΠ
1959 AIBS Bull. 9 45/1 Part IV..takes up the phyletic review, covering the protostome branch of the animal kingdom.
1987 M. S. Laverack & J. Dando Lect. Notes Invertebr. Zool. (ed. 3) xxi. 103/2 The nerve cord [of pogonophorans]..may be dorsally or ventrally placed depending upon whether a deuterostome or protostome relationship is considered.
2002 S. J. Gould Struct. Evolutionary Theory x. 1149 Comparisons..support the growing consensus..that the protostome phyla split into two great genealogical groups, the ecdysozoans or molting phyla..and the lophotrochozoans.
Derivatives
protoˈstomatous adj. = protostomous adj.
ΚΠ
1958 Q. Rev. Biol. 33 35/1 We are ignorant of the origin of the priapulids; and even the position of these three species of protostomatous, wormlike animals is uncertain.
1994 Ann. Rev. Ecol. & Systematics 25 359 In development, they [sc. nemertines] exhibit spiralian cleavage and are protostomatous.
protoˈstomous adj. = sense B.; (of an animal's mouth) derived from the embryonic blastopore.
ΚΠ
1961 Jrnl. Paleontol. 35 1073/2 Some zoologists believe that there must have been, in remote pre-Cambrian time, a trochophore phylum which was ancestral to all of the modern protostomous phyla.
1989 C. M. Lent & S. L. Adams in A. D. Woodhead Nonmammalian Animal Models for Biomed. Res. iii. 30 The protostomous developmental patterns of leech embryos facilitate fate-mapping experiments.
1997 Proc. National Acad. Sci. U.S.A. 94 8002/2 The phoronid celom can be interpreted as a schizocel and the mouth is, literally, protostomous. The mouth is not protostomous in the other lophophorates.
This is a new entry (OED Third Edition, September 2007; most recently modified version published online March 2022).
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n.adj.1884