Ellisella sp.

Chen, Jei-Ying & Williams, Gary C., 2015, X-ray Microanalysis and the Chemical Elemental Composition of Gorgonian and Pennatulacean Axial Structures (Anthozoa, Octocorallia), Proceedings of the California Academy of Sciences 62 (16), pp. 399-415 : 404-406

Ellisella sp.

Figures 5A–B , 6A–D.

From the linescan BSE image and the element linescan graph (Figure 6A and 6B) a high amount of calcium in the blue line can be seen spread through the horizontal axis surface, with an apparently declining pattern in the central axis region; the same trends can be observed in carbon (in red, 23.75 wt%), oxygen (in orange, 37.69 wt%) and magnesium (in light green, 2.14 wt%), which suggests that the core region of the axis contains lower amounts of the three major elements carbon (23.75 wt%), oxygen (37.69 wt%) and calcium (31.89 wt%), as well as magnesium (2.14 wt%), one of the two minor elements other than fluorine (3.40 wt%). All other trace elements like sodium (0.36 wt%), aluminum (0.05 wt%), sulfur (0.30 wt%), chlorine (0.23 wt%), iron (0.04 wt%), strontium (0.13 wt%) and REE ytterbium (0.14 wt%) have a more evenly distributed pattern with much flatter overall trends along the line. The weight percentage of all twelve identified elements is given in Table 3.

TABLE 3. EDS results of the sum spectrum for the gorgonian Ellisella sp. axial cross-section surface from Figure 6A. (All results are in weight%)

Element ਖ F Na Mg Al S Cl Ca Fe Sr Yb Total

Sum Spectrum

23.75 37.69 3.4 0.36 22.14 0.05 0.3 0.23 31.89 0.04 0.13 0.01 100 (Weight%)

C

FIGURE 6. Energy dispersive spectrometer (EDS) linescan dataset. (A) EDS linescan site of interest BSE image in a cross-sectional view of a gorgonian Ellisella sp. axial skeleton acquired by INCA Energy software using same region as Figure 5 , horizontal linescan through the middle of the axis was applied for EDS analysis to examine the distribution of elements along the line. Scale bar = 700 μm. (B) Element linescan result displaying grouped linescans as colored: carbon (red), oxygen (orange), fluorine (yellow), sodium (light green), magnesium (green), aluminum (pink), sulfur (aqua), chlorine (light blue), calcium (blue), strontium (indigo), ytterbium (purple), iron is not shown in the graph. (C) Sum spectrum of the linescan. (D) Bar chart of the quantitative results from the sum spectrum.

406 PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES Series 4, Volume 62, Part 2, No. 16

Figures

FIGURE 5. Scanning electron microscope (SEM) micrographs of a cross-sectional view of a gorgonian Ellisella sp. axial skeleton. (A) Secondary electron (SE) image. The axis of Ellisella sp. is featured by the concentric growth rings resembling that in trees, also by the slightly radiating patterns on the surface. These characters are useful for comparative morphology studies on calcaxonian gorgonians and sea pens. Scale bar = 200 μm. (B) Back-scattered electron (BSE) image. The compositional change is minute since again no detectable contrast is observed in the image though the topographical contrast is apparent like that in the SE image. Scale bar = 200 μm.