pentameren.
/ˈpɛntəmɪə/, U.S. /ˈpɛn(t)əˌmɪ(ə)r/ Zoology.
Each of the five divisions of an animal having fivefold symmetry.
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the world > animals > animal body > general parts > [noun] > regions comprising segments > segment > of a pentamerous animal
pentamere1900
1900 E. R. Lankester Treat. Zool. iii. 99 The whole animal can be divided into 5 corresponding and almost symmetrical sections, ‘pentameres’, by 5 imaginary ‘perradial planes’.
1946 H. Woods Palæontol. Invertebr. (ed. 8) 161 In the course of evolution,..the stem at first consists of cycles of five plates (pentameres) alternating in position; subsequently the five plates of a cycle become horizontal, and afterwards fuse to form a single columnal.
1992 Jrnl. Paleontol. 66 129 Ontogenetic development of the column of encrusting crinoids indicates that the evolution of holomeric columnals..need not have included gradual alignment of offset pentameres as intermediate steps.
This entry has been updated (OED Third Edition, September 2005; most recently modified version published online March 2022).
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n.1900