Fig 1.
Sampling of Hirondellea gigas.
a) Sampling location represented by the red dot. b) H. gigas collected in the bait trap. More than 200 individuals were collected. c) A micrographic montage of H. gigas under stereomicroscopy.
Fig 2.
EDS maps of semi-thin sections of H. gigas.
a) Transverse section through a subsample of pereonite. b) Transverse section of the cephalic region showing the gastric mill. c) Magnified images of the gastric mill, the red rectangle area in (b). Images from the left are SEM images at (a,b) 1 kV and (c) 10 kV, total X-ray counts (grayscale), phosphorous (green), calcium (blue), and aluminum-like signals around 1.48 keV (silver). EDS spectra were acquired at 10 kV, thus the K-line of bromine was not observed.
Fig 3.
X-ray spectra and elemental maps of a semi-thin section of the gastric mill in Hirondellea gigas.
a) SEM image of the mapped area. b) Point analysis at the red point in (a). c) WDS elemental maps of the orange rectangle in (a). Note that Al K contrast is significantly weaker than that of Br K.
Fig 4.
SEM images and elemental maps of a semi-thin section of the pereonite in Hirondellea gigas.
a) Low-magnification SEM image. b) High-magnification SEM image of the red rectangle in (a). c) WDS elemental maps of the orange rectangle in (b).
Fig 5.
SEM/EDS images of the gastric mill of Hirondellea gigas.
a) Low-magnification SEM image. b) Magnified image of the spine, yellow rectangle in part (a). c) Magnified image of the filter setae, orange rectangle in part (a), d) EDS elemental mapping and sum spectrum of the red rectangle in part (a). e) Line profile of the Br K intensity in EDS map along with the longitudinal axis of the ossicle spines. Profiles were shifted to the intensity direction for visibility, and average ± standard deviation of the intensity of 60 μm from root and 50 μm from the tip are shown in green and blue bars, respectively. The line profile was measured with the line width of 10 μm.
Fig 6.
SEM/EDS images of maxilla 2 of Hirondellea gigas.
a) Low-magnification SEM image. b) Magnified image of the yellow rectangle in part (a). c) EDS elemental mapping and sum spectrum of the red rectangle in part (a).
Fig 7.
SEM/EDS images of an antenna of Hirondellea gigas.
a) Low-magnification SEM image. b) Magnified image of the yellow rectangle in part (a). c) EDS elemental mapping and sum spectrum of the red rectangle in part (a).
Fig 8.
SEM/EDS images of a pleopod of Hirondellea gigas.
a) Low-magnification SEM image. b) Magnified image of the yellow rectangle in part (a). c) EDS elemental mapping and sum spectrum of the red rectangle in part (a).
Fig 9.
SEM images and EDS maps of an uropod of Hirondellea gigas.
a) Low-magnification image. b) High-magnification image of the yellow square in (a). c) Sum spectrum and EDS maps of the red square in (a). The sum spectra at 10–15 kV were magnified and displayed in the inset above with the same energy scale for clarity.
Fig 10.
SEM/EDS images of a coxal plate of Hirondellea gigas.
a) Low-magnification SEM image. b) Magnified image of the yellow rectangle in part (a). c) EDS elemental mapping and sum spectrum of the red rectangle in part (a).