Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotion

The locomotion strategies of fossil invertebrates are typically interpreted on the basis of morphological descriptions. However, it has been shown that homologous structures with disparate morphologies in extant invertebrates do not necessarily correlate with differences in their locomotory capabili...

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Main Authors: Elizabeth G. Clark, John R. Hutchinson, Peter J. Bishop, Derek E. G. Briggs
Format: Article
Language:English
Published: The Royal Society 2020-06-01
Series:Royal Society Open Science
Subjects:
Online Access:https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.200191
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author Elizabeth G. Clark
John R. Hutchinson
Peter J. Bishop
Derek E. G. Briggs
author_facet Elizabeth G. Clark
John R. Hutchinson
Peter J. Bishop
Derek E. G. Briggs
author_sort Elizabeth G. Clark
collection DOAJ
description The locomotion strategies of fossil invertebrates are typically interpreted on the basis of morphological descriptions. However, it has been shown that homologous structures with disparate morphologies in extant invertebrates do not necessarily correlate with differences in their locomotory capability. Here, we present a new methodology for analysing locomotion in fossil invertebrates with a rigid skeleton through an investigation of a cornute stylophoran, an extinct fossil echinoderm with enigmatic morphology that has made its mode of locomotion difficult to reconstruct. We determined the range of motion of a stylophoran arm based on digitized three-dimensional morphology of an early Ordovician form, Phyllocystis crassimarginata. Our analysis showed that efficient arm-forward epifaunal locomotion based on dorsoventral movements, as previously hypothesized for cornute stylophorans, was not possible for this taxon; locomotion driven primarily by lateral movement of the proximal aulacophore was more likely. Three-dimensional digital modelling provides an objective and rigorous methodology for illuminating the movement capabilities and locomotion strategies of fossil invertebrates.
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spelling doaj.art-06979b58323f401d8b94cc427ac7bf7d2022-12-21T19:37:59ZengThe Royal SocietyRoyal Society Open Science2054-57032020-06-017610.1098/rsos.200191200191Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotionElizabeth G. ClarkJohn R. HutchinsonPeter J. BishopDerek E. G. BriggsThe locomotion strategies of fossil invertebrates are typically interpreted on the basis of morphological descriptions. However, it has been shown that homologous structures with disparate morphologies in extant invertebrates do not necessarily correlate with differences in their locomotory capability. Here, we present a new methodology for analysing locomotion in fossil invertebrates with a rigid skeleton through an investigation of a cornute stylophoran, an extinct fossil echinoderm with enigmatic morphology that has made its mode of locomotion difficult to reconstruct. We determined the range of motion of a stylophoran arm based on digitized three-dimensional morphology of an early Ordovician form, Phyllocystis crassimarginata. Our analysis showed that efficient arm-forward epifaunal locomotion based on dorsoventral movements, as previously hypothesized for cornute stylophorans, was not possible for this taxon; locomotion driven primarily by lateral movement of the proximal aulacophore was more likely. Three-dimensional digital modelling provides an objective and rigorous methodology for illuminating the movement capabilities and locomotion strategies of fossil invertebrates.https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.200191echinodermstylophoraaulacophorethree-dimensional digital modellingrange of motion
spellingShingle Elizabeth G. Clark
John R. Hutchinson
Peter J. Bishop
Derek E. G. Briggs
Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotion
Royal Society Open Science
echinoderm
stylophora
aulacophore
three-dimensional digital modelling
range of motion
title Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotion
title_full Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotion
title_fullStr Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotion
title_full_unstemmed Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotion
title_short Arm waving in stylophoran echinoderms: three-dimensional mobility analysis illuminates cornute locomotion
title_sort arm waving in stylophoran echinoderms three dimensional mobility analysis illuminates cornute locomotion
topic echinoderm
stylophora
aulacophore
three-dimensional digital modelling
range of motion
url https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.200191
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AT peterjbishop armwavinginstylophoranechinodermsthreedimensionalmobilityanalysisilluminatescornutelocomotion
AT derekegbriggs armwavinginstylophoranechinodermsthreedimensionalmobilityanalysisilluminatescornutelocomotion