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Published December 2009 | Supplemental Material + Published
Journal Article Open

Functional Morphology and Fluid Interactions During Early Development of the Scyphomedusa Aurelia aurita


Scyphomedusae undergo a predictable ontogenetic transition from a conserved, universal larval form to a diverse array of adult morphologies. This transition entails a change in bell morphology from a highly discontinuous ephyral form, with deep clefts separating eight discrete lappets, to a continuous solid umbrella-like adult form. We used a combination of kinematic, modeling, and flow visualization techniques to examine the function of the medusan bell throughout the developmental changes of the scyphomedusa Aurelia aurita. We found that flow around swimming ephyrae and their lappets was relatively viscous (1 < Re < 10) and, as a result, ephyral lappets were surrounded by thick, overlapping boundary layers that occluded flow through the gaps between lappets. As medusae grew, their fluid environment became increasingly influenced by inertial forces (10 < Re < 10,000) and, simultaneously, clefts between the lappets were replaced by organic tissue. Hence, although the bell undergoes a structural transition from discontinuous (lappets with gaps) to continuous (solid bell) surfaces during development, all developmental stages maintain functionally continuous paddling surfaces. This developmental pattern enables ephyrae to efficiently allocate tissue to bell diameter increase via lappet growth, while minimizing tissue allocation to inter-lappet spaces that maintain paddle function due to boundary layer overlap.

Additional Information

© 2009 Marine Biological Laboratory. Received 7 May 2009; accepted 1 September 2009. The authors are grateful for financial support for this research from the National Science Foundation and the Office of Naval Research (OCE 9103309, OCE 0623508, N000140810654 to JHC; OCE-0351398 and OCE-0623534 to SPC; OCE-0623475 to JOD). We are grateful to E. Abbott for her assistance with artwork. We also thank S. Spina and the jellyfish crew at the New England Aquarium for their generous support in providing animals for study.

Attached Files

Published - Feitl2009p6903Biol_Bull-Us.pdf

Supplemental Material - Feitle_et_al_video_supplement_1.mov

Supplemental Material - feitl_et_al_supplementary_video_2.mov


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August 19, 2023
October 19, 2023