The balancing act of Nipponites mirabilis (Nostoceratidae, Ammonoidea): Managing hydrostatics throughout a complex ontogeny

Autor: David J. Peterman, Tomoyuki Mikami, Shinya Inoue
Jazyk: angličtina
Rok vydání: 2020
Předmět:
0106 biological sciences
Models
Anatomic
Muscle Physiology
Physiology
Hydrostatic pressure
Density
Geometry
Nipponites
Rotation
01 natural sciences
law.invention
law
Materials Physics
Morphogenesis
Biomechanics
Nautilus
Thrust
Multidisciplinary
biology
Physics
Classical Mechanics
Eukaryota
Condensed Matter Physics
Biological Evolution
Buoyancy
Physical Sciences
Medicine
Geology
Research Article
010506 paleontology
Cephalopods
Science
Movement
Materials Science
Material Properties
Shell (structure)
Fluid Mechanics
010603 evolutionary biology
Continuum Mechanics
Animal Shells
Hydrostatic Pressure
Animals
0105 earth and related environmental sciences
Organisms
Biology and Life Sciences
Fluid Dynamics
Molluscs
biology.organism_classification
Invertebrates
Physical Properties
Neutral buoyancy
Cephalopoda
Hydrodynamics
Nostoceratidae
Hydrostatic equilibrium
Musculoskeletal Mechanics
Zoology
Developmental Biology
Zdroj: PLoS ONE
PLoS ONE, Vol 15, Iss 8, p e0235180 (2020)
ISSN: 1932-6203
Popis: Nipponites is a heteromorph ammonoid with a complex and unique morphology that obscures its mode of life and ethology. The seemingly aberrant shell of this Late Cretaceous nostoceratid seems deleterious. However, hydrostatic simulations suggest that this morphology confers several advantages for exploiting a quasi-planktic mode of life. Virtual, 3D models of Nipponites mirabilis were used to compute various hydrostatic properties through 14 ontogenetic stages. At each stage, Nipponites had the capacity for neutral buoyancy and was not restricted to the seafloor. Throughout ontogeny, horizontally facing to upwardly facing soft body orientations were preferred at rest. These orientations were aided by the obliquity of the shell's ribs, which denote former positions of the aperture that were tilted from the growth direction of the shell. Static orientations were somewhat fixed, inferred by stability values that are slightly higher than extant Nautilus. The initial open-whorled, planispiral phase is well suited to horizontal backwards movement with little rocking. Nipponites then deviated from this bilaterally symmetric coiling pattern with a series of alternating U-shaped bends in the shell. This modification allows for proficient rotation about the vertical axis, while possibly maintaining the option for horizontal backwards movement by redirecting its hyponome. These particular hydrostatic properties likely result in a tradeoff between hydrodynamic streamlining, suggesting that Nipponites assumed a low energy lifestyle of slowly pirouetting in search for planktic prey. Each computed hydrostatic property influences the others in some way, suggesting that Nipponites maintained a delicate hydrostatic balancing act throughout its ontogeny in order to facilitate this mode of life.
Databáze: OpenAIRE
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