Ammonitellaとは 意味・読み方・使い方

名詞

ammonitella (複数形 ammonitellas)

1. The initial part of a spiral shell, originating from a central chamber, in ammonoid molluscs
   • 2016 January 14, “Paleobiology of the Latest Tithonian (Late Jurassic) Ammonite Salinites grossicostatum Inferred from Internal and External Shell Parameters”, in PLOS ONE‎^[1], DOI:10.1371/journal.pone.0145865:

     The embryonic stage, consisting of a small ellipsoid protoconch and ammonitella, ends at about 0.6 mm.

   • 2017, Danna Staaf, Squid Empire, ForeEdge, →ISBN, page 61:

     Sure, ammonoid shells as a whole got progressively more coiled over the Devonian. But so did the tiniest part of each ammonoid shell, the ammonitella.