Electronic versions



  • Marilia Ragagnin
    Universidade de São Paulo
  • Daniel Gorman
    Universidade de São Paulo
  • Ian McCarthy
  • Bruno Sant'Anna
    Universidade Federal do Amazonas
  • Claudio Campi de Castro
    Universidade de São Paulo
  • Alexander Turra
    Universidade de São Paulo
Obtaining accurate and reproducible estimates of internal shell volume is a vital requirement for studies into the ecology of a range of shell-occupying organisms, including hermit crabs. Shell internal volume is usually estimated by filling the shell cavity with water or sand, however, there has been no systematic assessment of the reliability of these methods and moreover no comparison with modern alternatives, e.g., computed tomography (CT). This study undertakes the first assessment of the measurement reproducibility of three contrasting approaches across a spectrum of shell architectures and sizes. While our results suggested a certain level of variability inherent for all methods, we conclude that a single measure using sand/water is likely to be sufficient for the majority of studies. However, care must be taken as precision may decline with increasing shell size and structural complexity. CT provided less variation between repeat measures but volume estimates were consistently lower compared to sand/water and will need methodological improvements before it can be used as an alternative. CT indicated volume may be also underestimated using sand/water due to the presence of air spaces visible in filled shells scanned by CT. Lastly, we encourage authors to clearly describe how volume estimates were obtained.
Original languageEnglish
Article number440
JournalScientific Reports
Publication statusPublished - 11 Jan 2018

Total downloads

No data available
View graph of relations