Measurements taken using ImageJ (version 1.44p; National Institute of Health, USA). Specimens settled individually in a cylindrical tube of 155mm depth and 140mm diameter. A high-speed camera (Vision Research Phantom v.9.1, sampling rate=10pps, pixel resolution:1440x720, exposure=3000µs) was used to record settling, and calculation of settling velocity from 20 consecutive image frames in the lowest 30mm confirmed terminal velocity.