subzonaladj.
/ˌsʌbˈzəʊnl/, U.S. /ˌsəbˈzoʊn(ə)l/ 1. Embryology. Located or occurring beneath the zona pellucida of an ovum.
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the world > life > biology > biological processes > procreation or reproduction > reproductive substances or cells > [adjective] > ovum > fertilized ovum and parts
segmented1875
stirpal1875
subzonal1875
1875 Lancet 19 June 863/1 Beneath this was subsequently formed the subzonal membrane, corresponding to the serous layer of anatomists.
1877 W. Turner Introd. Human Anat. II. 864 The formation of the amnion and sub-zonal outer layer of the persistent chorion.
1922 E. J. Menge Gen. & Professional Biol. xlvi. 621 The sub-zonal layer is only one cell in thickness, so it is easily distinguished from the inner cell mass.
1980 Copeia No. 2. 211/2 A few investigators claim to have observed a subzonal radially striated layer at the oocyte surface in some species.
2000 Cutting Edge: Encycl. Adv. Technol. 158/1 Subzonal insemination (SUZI) involves the injection of a single sperm cell between the outer coat of the egg and the cell's plasma membrane.
2. Chiefly Palaeontology and Ecology. Of or relating to a subzone.
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1905 A. Vaughan in Q. Jrnl. Geol. Soc. 61 185 A series of subzonal indices was next adopted, to designate the parts of a zone, whenever a marked change of fauna naturally called for the subdivision of a zone.
1952 Jrnl. Ecol. 40 55 Fig. 6 demonstrates clearly the presence of a Betula-dominated subzonal belt fringing the main drove.
2005 M. B. Aguirre-Urreta et al. in G. D. Viega et al. Neuquén Basin, Argentina 60/2 Examples of each zonal/subzonal index fossil are illustrated in Figs 4–7.
This entry has been updated (OED Third Edition, June 2012; most recently modified version published online March 2022).
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adj.1875