Empirical 3D model of the conch of the Middle Jurassic ammonite microconch<i>Normannites</i>: its buoyancy, the physical effects of its mature modifications and speculations on their function

Tajika, Amane; Naglik, Carole; Morimoto, Naoki; Pascual-Cebrian, Enric; Hennhöfer, Dominik K.; Klug, Christian

doi:10.1080/08912963.2013.872097

Cited by 53 publications

(106 citation statements)

References 40 publications

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“…4.6). Similar shallow imprints can be seen in modern nautilids: In some Nautilus conchs, Klug et al (2008) found imprints of the left and right septal arteries, the siphuncular artery and the accessory siphuncular arteries (see also Deecke 1913, andStenzel 1964, who figured a Nautilus septum showing soft tissue imprints). Corresponding to this fact, the imprints on the septa of the Devonian ammonoids were interpreted as imprints of arteries, providing the septal mantle with arterial blood.…”

Section: Blood Vessel Imprintsmentioning

confidence: 77%

“…Some of these wrinkles lie in the plain of symmetry (septal furrow ;Stenzel 1964;Teichert 1964;Chirat and von Boletzky 2003) and some diverge from the plain of symmetry at a low angle, originating near the siphuncle (Fig. 4.6).…”

Section: Blood Vessel Imprintsmentioning

confidence: 99%

“…Taking the potentially large amount of chamber water (up to 30 % of phragmocone volume ;Heptonstall 1970;Mutvei and Reyment 1973;Reyment 1973;Ward 1979;Tajika et al 2014) in the phragmocone into account, water movement might have altered the orientation of the shell syn vivo. Cameral membranes would have limited the water movement within the phragmocone chambers and thus enhanced stability.…”

Section: Functionmentioning

confidence: 99%

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

Polizzotto

Landman

Klug

2015

Topics in Geobiology

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

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Section: Blood Vessel Imprintsmentioning

confidence: 77%

Section: Blood Vessel Imprintsmentioning

confidence: 99%

Section: Functionmentioning

confidence: 99%

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

Polizzotto

Landman

Klug

2015

Topics in Geobiology

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“…Several researchers assumed that the density of the ammonoid soft body (ca 1.055 g/cm 3 according to Shapiro 1986 andTajika et al 2015), was only slightly higher than that of seawater (1.020 to 1.029 g/cm 3 ). In this case, the influence of the mantle cavity and the effect of shifting of the head region outside of the body chamber may have been relatively small.…”

Section: B C Amentioning

confidence: 99%

“…In many taxa, this could have been a rather heavy part of the body including the head, jaw apparatus (with large calcified aptychi in the case of ammonites with aptychus-type jaws), hyponome and arms (although it is unknown what they looked like and whether they were muscular). At the same time, in most of all computations published to date, it is explicitly or implicitly assumed that the soft body of ammonoids with planispiral shells was located entirely within the body chamber (Trueman 1941, Raup & Chamberlain 1967, Saunders & Shapiro 1986, Westermann 1996, Naglik et al 2014, Tajika et al 2015. Since these authors did not take the protrusion of the cephalic region out of the body chamber into account, the apertures of many ammonites are located in a nearly horizontal position (Trueman 1941, figs 14, 15;Saunders & Shapiro 1986, fig.…”

Section: Supracephalic Attachment Area: Implications For Ammonoid Apementioning

confidence: 99%

Wrinkle layer and supracephalic attachment area: implications for ammonoid paleobiology

Mironenko¹

2015

Bull. Geosci.

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In many planispiral ammonoid shells, the dorsal wrinkle layer is located not only inside the body chamber, but also protruded beyond the apertural edge, covering the part of the penultimate shell whorl in front of the aperture (similar to the black layer of Recent Nautilida). This external (relative to the body chamber) part of the wrinkle layer was rarely the focus of research and its implications for ammonoid paleobiology have not been studied in detail. This paper deals with this area found on the shells of seven genera of planispiral Jurassic (Callovian and Oxfordian) ammonites from Central Russia. The size and shape of this area as well as the surface structure of well-preserved specimens are described. The proposed name "supracephalic attachment area" (SCAA) represents the location and presumed biological significance of this part of the wrinkle layer. The implications of the existence of this area for the ammonoid mode of life, soft body structure and aperture orientation are discussed. The location of the part of the wrinkle layer outside of the body chamber proves that some part of the ammonoid soft body (likely the cephalic region) moved forward beyond the aperture during active swimming. This forces a review of calculations of ammonite aperture orientation which were based on the postulate that the soft body was located largely within the body chamber. Aleksandr A. Mironenko, Kirovogradskaya st. 28, 117519 Moscow, Russia; paleometro@gmail.com The ammonoid wrinkle layer -a part of the shell with more or less prominent wrinkles on the surface -has been studied for more than 150 years. This organic-rich layer covers dorsal, ventral and lateral walls inside the ammonoid body chamber and forms part of the dorsal shell wall. It is well studied in different ammonoid genera (Quenstedt

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Finite Element Analysis as a Method to Study Molluscan Shell Mechanics

Lemanis

Zlotnikov

2017

Adv Eng Mater

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The clade Mollusca is a highly diverse and disparate group of terrestrial and aquatic invertebrates, the taxon containing over 100 000 known species including some of the most intelligent invertebrate animals. Their shells are exemplar systems in the study of biomechanics, biomineralization, and biomimetics. Research into understanding the superior biomechanical properties of the shell and how these properties relate to the animals ecology have required a diverse range of methods at multiple length scales; one particularly powerful method is finite element analysis. Finite element analysis is a robust engineering method that has a long-standing history in biomechanical research. This review summarizes the application of finite element analysis in the study of both the mechanical properties of different molluscan shell ultrastructures as well as macro-scale modeling of the shell. From the calculation of elastic constants to the origins of the strength of nacre and the relationship between shell folding and ecology, this article provides a window into how finite element analysis can further our understanding of mechanics and functional morphology.

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Empirical 3D model of the conch of the Middle Jurassic ammonite microconchNormannites: its buoyancy, the physical effects of its mature modifications and speculations on their function

Cited by 53 publications

References 40 publications

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

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

Wrinkle layer and supracephalic attachment area: implications for ammonoid paleobiology

Finite Element Analysis as a Method to Study Molluscan Shell Mechanics

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