Kingdom...... Animalia Anaptychus: one-valved Microconch: smaller form, Phylum...... Mollusca Ammonite Anatomy & Terms aptychus. usually male. Class...... Cephalopoda Subclass...... Ammonoidea Aptychus: pair of plates, Nacre: iridescent mother of Order...... Ammonitida aptychi, to close the aperture pearl. Palaeoammonoid Suborders..... Anarcestina, Clymeniina, Goniatitina, and Prolecanitina or possibly jaws. Mesoammonoids Suborder...... Ceratitina Ornament: external portion Neoammonoid Suborders...... Ammonitina, Ancyloceratina, Phylloceratina, and Lytoceratina Conch: one-piece shell of a of shell anatomy such as mollusc. spines, striations, ribs, Mollusc shells are made of calcite, aragonite, and conchiolin which is a tough, insoluble protein tubercles, bullae, and clavi. Heteromorph: ammonoid matrix within which calcium carbonate is deposited. shell that is any form except Planispiral: coiling in one planispiral with whorls plane. Involute: whorls overlapping, giving Evolute: whorls not overlapping touching. small or compressed umbilicus. or little overlapping. Whorl: one full revolution of Macroconch: larger form, the shell, 360 degrees. usually female. Siphuncle: tube that is on the shell’s outer rim Whorl connecting the chambers of the phragmocone to Width the living chamber. Flank: Lobe: suture Saddle: lateral wall line that suture line of shell, points away that points also called Whorl from the towards the whorl side. Height aperture. aperture. Suture: where the septa intersect the outer portion of the shell. Phragmocone: Siphuncle Goniatitic: usually 8 lobes chambered portion Umbilicus: around the conch, typical of of shell composed external Paleozoic ammonoids. of individual center Protoconch: first chamber of the shell. chambers called depressed camerae (singular portion of is called camera). the shell. The chambers are Umbilical Seam: attachment of the shell separated by septa wall with the preceding whorl. Ceratitic: lobes have saw (singular is septum). toothed appearance, typical Umbilical Wall: the portion between of Triassic ammonoids. umbilical seam and umbilical shoulder. Aperture: opening of Living chamber or body chamber. Umbilical Shoulder: the shell wall bends body chamber: portion toward the preceding whorl. of the shell from the phragmocone to the aperture where the live organism occupied. Ventrolateral Shoulder: the shell bends Ammonitic: lobes and saddles fluted, typical of Jurassic and Venter: outer rim toward the venter. © Cynthia Cassell 2020 Cretaceous ammonoids. of the shell, keel.