Cameral Membranes, Pseudosutures, and Other Soft Tissue Imprints in Ammonoid Shells

摘要: Ammonoids occasionally show subtle structures linked with the attachment or contact of soft body shell. Only some these were mineralized and thus are rarely preserved. We describe mainly three different kinds structures, namely (i) cameral membranes, (ii) muscle imprints (excluding structures) (iii) blood vessels. Cameral membranes have been discovered only in a small fraction ammonoid species close to siphuncle cut off parts chambers separate chamber volumes vertically. Pseudosutures commonly run subparallel normal sutures, although they fainter. They likely formed during forward movement septal mantle prior insertion new septum. Drag lines also developed course this process may represent fibers. Blood vessels left shells.