• Corpus ID: 195258934

12 Speculations on Buoyancy Control and Ecology in some Heteromorph Ammonites

  title={12 Speculations on Buoyancy Control and Ecology in some Heteromorph Ammonites},
  author={Herbert Christian Klinger},
Possible buoyancy control in some heteromorph ammonite groups is investigated in terms of the position of the siphuncle. Groups investigated include some torticones, ancylocones and orthocones. In Turrilitinae the •idapical position of the siphuncle causes rapid decoupling and may possibly permit the shell to retain significant amounts of cameral liquid, which may be lavourable to a vagile benthonic mode of life. Ancylocones have a very stable floating position in the adult stage, but lateral… 
Speculations on the ethology of some heteromorph ammonites
The mode of life of the turricones and colchicones are considered against the background of functional–morphological analyses of their shell modifications during ontogeny and transformation from helical to planispiral coiling indicates a transition to a more active, free-swimming mode oflife.
Stable hooks: biomechanics of heteromorph ammonoids with U-shaped body chambers
The biomechanics of uncoiled heteromorph ammonoids with body chambers that terminate in U-shaped hooks (ancylocones) were investigated with virtual and physical models of Audouliceras renauxianum to suggest that stability, orientation and directional efficiency are key selective pressures for some heteromorph shells, which may have primarily served as hydrostatic devices.
Syn vivo hydrostatic and hydrodynamic properties of scaphitid ammonoids from the U.S. Western Interior
Abstract Scaphitid ammonoids were ubiquitous and significant components of the Western Interior Seaway during the Late Cretaceous. This group is characterized by a recurved hook at maturity that
Mode of life and hydrostatic stability of orthoconic ectocochleate cephalopods: hydrodynamic analyses of restoring moments from 3D-printed, neutrally buoyant models
Theoretical 3D models were digitally reconstructed from a phragmocone section of Baculites compressus in order to investigate the hydrostatic properties of the orthoconic morphotype. These virtual
Recent advances in heteromorph ammonoid palaeobiology
An improved understanding of heteromorph ammonoid palaeobiology is reached, linking their small hatchling sizes, planktotrophic diets, and higher metabolic rates than in nautilids, which survived the K/Pg mass extinction event.
Heteromorph Ammonoids of the Triassic : A Review
Tiny heteromorphs that suddenly appeared ai the end of the Norian possessed semievolute, com­ pletely straight or slightly curved, twisted or lurriconic shells, with coarse ornamentation and a simple
The hydrostatics of Paleozoic ectocochleate cephalopods (Nautiloidea and Endoceratoidea) with implications for modes of life and early colonization of the pelagic zone
Understanding the hydrostatic properties of ectocochleate cephalopods is essential to study the functional morphology of their shells. The conditions for neutral buoyancy, static orientation of the
Getting hooked: the role of a U-shaped body chamber in the shell of adult heteromorph ammonites
Comparison of the adult mode of life with those of modern cephalopods suggested that ammonites of the suborder Ancyloceratina had developed a stationary brooding phase that could have several ecological advantages over free-swimming monomorph ammonites.
A New Species of Yezoceras (Ammonoidea, Nostoceratidae) from the Coniacian in the Northwestern Pacific Realm
Abstract. A nostoceratid ammonoid Yezoceras elegans sp. nov. is newly described from the Coniacian of the Haboro area in Hokkaido, northern Japan. Yezoceras elegans sp. nov. having loosely coiled
A new approach using high-resolution computed tomography to test the buoyant properties of chambered cephalopod shells
A technique using high-resolution computed tomography to quantify the buoyant properties of chambered shells without reducing the shell to ideal spirals or eliminating inherent biological variability is developed, which challenges past inferences of benthic life habits based solely on calculations of negative buoyancy.


A specimen of Buchiceras bilobatum is shown to have been able to maintain neutral buoyancy in water despite the ever increasing weight of epifaunal oysters which it carried on its shell. It is
On the buoyancy of the pearly Nautilus
It is concluded that the phragnocone-cameral liquid system is utilized for long term buoyancy adjustments rather than short term changes which might aid vertical ascent or descent.
Floatation Mechanisms in Modern and Fossil Cephalopods
This chapter discusses the floatation mechanisms in modern and fossil cephalopods with chambered shells and compares the buoyancy of different animals by expressing their weights in sea water as percentages of their weight in air.
Cephalopod Adaptations-The Record and Its Interpretation
  • E. Berry
  • Geography
    The Quarterly Review of Biology
  • 1928
Department of Geology, Johns Hopkins University IT SHOULD be recognized at the outset that the present paper is highly speculative in character. Not that the author has much faith in such a method of
Camouflage patterns in Nautilus, and their implications for cephalopod paleobiology
‘Ornament’ on ammonoids is seen as camouflage structure, and the principles of camouflage are used to re-assess some facets of cephalopod paleobiology; the life orientation of some early cyrtocones is re-interpreted.
The ammonite body-chamber, with special reference to the buoyancy and mode of Life of the living ammonite
  • A. E. Trueman
  • Geology
    Quarterly Journal of the Geological Society of London
  • 1940
I. Introduction In many works relating to the classification and morphology of ammonites reference has been made to the length of the body-chamber and to the form of the mouth border. There have been
Architecture and buoyancy of simple cephalopod phragmocones and remarks on ammonites
Abstracthydrostatic model of simple phragmocones consists of orthoconic shell wall and adorally concave, spherically curved septa acting as membranes, which requires correlation between apical angle, cameral length, and shell thickness.
The foundation of these ancient tales is based on giant squids defending itself against its main predator, a sperm whale, rather than octopuses, which has led to overestimates of squid body lengths of more than 100 m.