protochordaten.adj.
/ˌprəʊtə(ʊ)ˈkɔːdeɪt/, /ˌprəʊtə(ʊ)ˈkɔːdət/, U.S. /ˌproʊdoʊˈkɔrdət/, /ˌproʊdoʊˈkɔrˌdeɪt/ Zoology.
A. n.
Any of the small marine animals belonging to the phylum Hemichordata or to either of the chordate subphyla Urochordata and Cephalochordata, characterized (at some point in the life cycle) by a hollow dorsal nerve cord, a notochord, and gill slits; a hemichordate, urochordate, or cephalochordate, or a hypothetical ancestral form of any of these.The protochordates lack a skull and vertebrae and are believed to resemble the ancestors of the vertebrates.
ΘΚΠ
the world > animals > invertebrates > subkingdom Metazoa > grade Triploblastica or Coelomata > phylum Hemichordata > [noun] > other types of
protochordate1894
1894 A. Willey Amphioxus & Ancestry of Vertebrates v. 242 Of the free-living protochordates, the lowest type of organisation is undoubtedly presented by the Enteropneusta (Hemichorda).
1918 H. F. Osborn Orig. & Evol. Life viii. 246 The principal..secretory glands..doubtless had their beginnings among the ancestors (protochordates) of the vertebrated animals.
1951 C. K. Weichert Anat. Chordates ii. 12 The animals included in this category are believed to show similarities to the ancestors of the chordates and for this reason are sometimes called the protochordates.
2002 Proc. National Acad. Sci. U.S.A. 99 16841/2 Only one Snail gene is present in protochordates.
B. adj.
Of or designating a protochordate.
ΘΚΠ
the world > animals > invertebrates > subkingdom Metazoa > grade Triploblastica or Coelomata > phylum Hemichordata > [adjective] > of other types of
protochordate1894
1894 A. Willey Amphioxus & Ancestry of Vertebrates v. 282 There is no a priori reason for doubting that the Vertebrate mouth is completely homologous with the Protochordate mouth.
1937 Philos. Trans. (Royal Soc.) B. 228 308 This is not to suggest that the diverticulum of the ammocoete..actually evolved directly from the diverticulum of a Protochordate ancestor.
2000 Proc. National Acad. Sci. U.S.A. 97 6926/2 Early attempts failed to identify the protochordate histocompatability genes by homology to vertebrate MHC receptors.
This entry has been updated (OED Third Edition, September 2007; most recently modified version published online March 2022).
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n.adj.1894