Scaling effects in caudal fin propulsion and the speed of ichthyosaurs

  title={Scaling effects in caudal fin propulsion and the speed of ichthyosaurs},
  author={Ryosuke Motani},
  • R. Motani
  • Published 17 January 2002
  • Environmental Science
  • Nature
Four unrelated groups of large cruising vertebrates (tunas, whales, lamnid sharks and parvipelvian ichthyosaurs) evolved tuna-shaped (thunniform) body plans. Stringent physical constraints, imposed by the surrounding fluids, are probably responsible for this example of evolutionary convergence. Here I present a mathematical model of swimming kinematics and fluid mechanics that specifies and quantifies such constraints, and test the model with empirical data. The test shows quantitatively that… 

Convergent evolution in mechanical design of lamnid sharks and tunas

It is demonstrated that not only have lamnids and tunas converged to a much greater extent than previously known, but they have also developed morphological and functional adaptations in their locomotor systems that are unlike virtually all other fishes.

Ontogenetic Scaling of Caudal Fin Shape in Squalus acanthias (Chondrichthyes, Elasmobranchii): A Geometric Morphometric Analysis With Implications for Caudal Fin Functional Morphology

The data suggest a combination of caudal fin morphology with other body morphology aspects, would refine, and better elucidate the hydrodynamic factors (if any) that underlie the significant shape changes reported here for S. acanthias.

Scaling of swimming performance in baleen whales

Motion-sensing tags attached to baleen whales paired with unoccupied aerial system (drone) imagery demonstrate that while oscillatory stroking frequency decreases with size, absolute swimming speed remains consistent over an order of magnitude body mass range.

Scaling of oscillatory kinematics and Froude efficiency in baleen whales

This work used data from whale-borne inertial sensors coupled with morphometric measurements from aerial drones to calculate the hydrodynamic performance of oscillatory swimming in six baleen whale species and found that mass-specific thrust increased with both swimming speed and body size.

Evolution of Fish-Shaped Reptiles (reptilia: Ichthyopterygia) in Their Physical Environments and Constraints

Ichthyosaurs were a group of Mesozoic marine reptiles that evolved fish-shaped body outlines that allowed estimation of such characteristics as optimal cruising speed, visual sensitivity, and even possible basal metabolic rate ranges.

Ontogenetic Scaling of Body Proportions In Waterfall-climbing Gobiid Fishes from Hawai'i and Dominica: Implications for Locomotor Function

The differing scaling patterns of sucker area and caudal-fin height relative to body length may reflect an increase in the importance of swimming over climbing in sicydiine gobies as they grow larger.

Flying and swimming animals cruise at a Strouhal number tuned for high power efficiency

Tuning cruise kinematics to optimize St seems to be a general principle of oscillatory lift-based propulsion of swimming and flying animals.

Ontogeny of head and caudal fin shape of an apex marine predator: The tiger shark (Galeocerdo cuvier)

Changes in the shape of the head and caudal fin of tiger sharks across ontogeny are interpreted as a result of two ecological transitions, which could have effects for other species that tiger sharks consume and interact with.

The locomotion of extinct secondarily aquatic tetrapods

  • Susana GutarraI. Rahman
  • Biology, Environmental Science
    Biological reviews of the Cambridge Philosophical Society
  • 2021
An overview of the latest research on the locomotion of extinct secondarily aquatic tetrapods, with a focus on amniotes, highlighting the state‐of‐the‐art experimental approaches used in this field and discussing the suitability of these techniques for exploring different aspects of locomotory adaptation.

Soft tissue preservation in a fossil marine lizard with a bilobed tail fin.

This fossil is reported from the Maastrichtian of Harrana in central Jordan, which preserves soft tissues, including high fidelity outlines of a caudal fluke and flippers, which provides the first indisputable evidence that derived mosasaurs were propelled by hypocercal tail fins.




  • DewarGraham
  • Environmental Science
    The Journal of experimental biology
  • 1994
Yellowfin tuna (Thunnus albacares) swimming kinematics was studied in a large water tunnel at controlled swimming velocities and the morphological and anatomical adaptations associated with the long propulsive wavelength act to minimize anterior resistance and maximize caudal thrust.

Comparative kinematics and hydrodynamics of odontocete cetaceans: morphological and ecological correlates with swimming performance.

  • F. Fish
  • Environmental Science
    The Journal of experimental biology
  • 1998
The results indicate that the kinematics of the propulsive flukes and hydrodynamics are associated with the swimming behaviors and morphological designs exhibited by the whales in this study, although additional factors will influence morphology.

Propulsion of a fin whale ( Balenoptera physalus) : why the fin whale is a fast swimmer

  • N. BoseJ. Lien
  • Engineering
    Proceedings of the Royal Society of London. B. Biological Sciences
  • 1989
A strip theory was developed to calculate the hydrodynamic performance of the whale’s flukes as an oscillating propeller and the effects of the different correction factors, and of the frictional drag of the fluke sections, are emphasized.


Summary The power output and propulsive efficiency of swimming bottlenose dolphins (Tursiops truncatus) were determined from a hydromechanica l model. The propulsive movements were filmed as dolphins

Tail kinematics of the chub mackerel Scomber japonicus: testing the homocercal tail model of fish propulsion.

The results suggest that the caudal fin of the chub mackerel is not functioning symmetrically according to the homocercal model and could produce upward lift during steady swimming.

Swimming speed estimation of extinct marine reptiles: energetic approach revisited

  • R. Motani
  • Environmental Science
  • 2002
The amended method successfully approximates published optimal speeds of several extant marine vertebrates, including cetaceans, showing that the basic framework of the energetic approach is valid and support previous inferences about the relative cruising capabilities of Mesozoic marine reptiles.

Swimming capabilities of Mesozoic marine reptiles: implications for method of predation

Estimating the total drag and the amount of energy available through metabolism, the maximum sustained swimming speed was calculated for 115 marine reptile specimens and suggests that the long-bodied forms probably used an ambush technique to capture prey, to maximize the range of possible prey and to minimize competition with the faster pursuit predators.

Fast Continuous Swimming of Two Pelagic Predators, Saithe (Pollachius Virens) and Mackerel (Scomber Scombrus): a Kinematic Analysis

Straight, forward, unrestrained swimming behaviour, with periodic lateral oscillations of body and tailfin, was described and compared for saithe and mackerel and yields a Froude efficiency close to the maximum value possible, given the observed amplitude increase in the posterior part.

The metabolic cost of swimming in marine homeotherms.

The work shows the metabolic Costs of propulsion and thermoregulation in a swimming homeotherm to be interlinked and suggests differing costs of propulsion for different modes of swimming.

The Use of Gait Transition Speed in Comparative Studies of Fish Locomotion

The pectoral-caudal gait transition speed, or any percentage thereof, is shown to be 'biomechanically equivalent' for swimmers of different size, and has the important implication that length-specific speeds may not induce comparable degrees of exercise from different fishes, and thus kinematic and physiological comparisons at such speeds can yield misleading results.