Reevaluating hydrodynamic performance of Late Triassic–Early Jurassic ammonoid shells with a 1D trajectory model

Hebdon, Nicholas; Ritterbush, Kathleen A.; Choi, Yoon Ji; Peterman, David J.

doi:10.1016/j.geobios.2022.02.002

Cited by 5 publications

(2 citation statements)

References 37 publications

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“…Unfortunately, some of these fundamental questions in ammonoid paleobiology remain unanswered. For example, the morphology of the arm crown remains largely unknown and long-standing hypotheses about the connection between shell shape, hydrodynamics, and ecology have only recently begun to be quantified and tested (13)(14)(15)(16)(17)(18) since earlier work in the late 1900s (19)(20)(21)(22)(23)(24). Nevertheless, what might be the longest-lasting question with regard to ammonoid biology, the question of the function of the fractal-like septa, remains open.…”

Section: Introductionmentioning

confidence: 99%

Fractal-like geometry as an evolutionary response to predation?

Lemanis

Zlotnikov

2023

Sci. Adv.

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Fractal-like, intricate morphologies are known to exhibit beneficial mechanical behavior in various engineering and technological domains. The evolution of fractal-like, internal walls of ammonoid cephalopod shells represent one of the most clear evolutionary trends toward complexity in biology, but the driver behind their iterative evolution has remained unanswered since the first hypotheses introduced in the early 1800s. We show a clear correlation between the fractal-like morphology and structural stability. Using linear and nonlinear computational mechanical simulations, we demonstrate that the increase in the complexity of septal geometry leads to a substantial increase in the mechanical stability of the entire shell. We hypothesize that the observed tendency is a driving force toward the evolution of the higher complexity of ammonoid septa, providing the animals with superior structural support and protection against predation. Resolving the adaptational value of this unique trait is vital to fully comprehend the intricate evolutionary trends between morphology, ecological shifts, and mass extinctions through Earth’s history.

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Section: Introductionmentioning

confidence: 99%

Fractal-like geometry as an evolutionary response to predation?

Lemanis

Zlotnikov

2023

Sci. Adv.

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“…However, apart from very recent contributions (e.g., refs. [11][12][13]) and calculations and measurements of the drag force [6,14], less attention has been paid to simulating ammonoid swimming and locomotion. Another reason is that locomotion is crucially linked not only to the usually well-conserved shell but also to the soft body parts, the funnel and the mantle cavity.…”

Section: Introductionmentioning

confidence: 99%

The Hydrodynamics of Ammonoid Swimming: Equations of Motion and Rocking Resonances

De Blasio

2023

Fossil Studies

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This work explores the swimming of ammonoids, cephalopods related to living squids, octopuses, and nautilids and, like the latter, equipped with a coiled external shell. A mathematical model is introduced for theoretical ammonoid conchs. The two differential equations of motion (one for the centre of mass, including the drag force and the added mass coefficient, and one for the roll angle) are solved numerically for the theoretical conchs, and the results are analysed in terms of velocity and rocking angle. Destabilising resonances occur when the rocking motion is in phase with the propelling water jet. It is suggested that the ammonoids partly evolved avoiding the occurrence of such resonances in their construction.

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Theoretical morphological analysis of differential morphospace occupation patterns for terrestrial and aquatic gastropods

Araki

Noshita

2023

Evolution

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Despite the morphological diversity of organisms, they only occupy a fraction of the theoretically possible spectrum (i.e., morphospace) and have been studied on several taxa. Such morphospace occupation patterns are formed through evolutionary processes under multiple constraints. In this study, we discovered a differential morphospace occupation pattern between terrestrial and aquatic gastropods, and subsequently attempted to quantitatively understand these differences through morphospace analysis. These differential occupation patterns between terrestrial and aquatic species were observed in the morphospace of spire height and aperture inclination, including a bimodal distribution of shell height in terrestrial species alongside an absence of high-spired shells with high aperture inclination. Although terrestrial species were distributed along optimal lines of shell instability and shell hindrance to locomotion, aquatic species were distributed not only along this line but also within a suboptimal region of the low spire with low inclination. Based on numerical simulation and biometric analysis, here we propose the hypothesis that this difference was caused by the aquatic species being able to adopt a posture with the growth direction perpendicular to the substrate due to reduced functional demands. Our results provided an ultimate explanation for the differential occupation patterns between habitats alongside an overview of the morphospace.

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Reevaluating hydrodynamic performance of Late Triassic–Early Jurassic ammonoid shells with a 1D trajectory model

Cited by 5 publications

References 37 publications

Fractal-like geometry as an evolutionary response to predation?

Fractal-like geometry as an evolutionary response to predation?

The Hydrodynamics of Ammonoid Swimming: Equations of Motion and Rocking Resonances

Theoretical morphological analysis of differential morphospace occupation patterns for terrestrial and aquatic gastropods

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