1. Sand incorporated into outer column of polyps, polyps feel rough—-10.
2. Polyps feel smooth to the touch, lack sand —3.
3. Polyps embedded into coenenchyme forming a dense mat-like colony Zoanthus kuroshio (Indo-Pacific) Zoanthus aff. pulchellus (Caribbean)
4. Polyps are not embedded into coenenchyme—5.
5. Closed polyps have large white striped pattern and mouth is green in color —Zoanthus gigantus (Indo-Pacific) Zoanthus solanderi (Caribbean)
6. Closed polyps display only minor markings or no obvious markings at all — 7.
7. Open polyps display a radial pattern, often a variation of red, pink or purple with a white mouth — Zoanthus pulchellus (Caribbean) Zoanthus vietnamensis (Indo-Pacific)
8. Coloration of oral disk does not display a radial pattern— 9.
9. Oral disk may be a variety of colors displaying sometimes elaborate color patterns— Zoanthus sansibaricus (Indo-Pacific) Zoanthus sociatus (Caribbean)
10. Polyps may be unitary or interconnected but are not embedded into the coenechyme, tentacles appear straight, alternating up and down — Palythoa mutuki (Indo-Pacific) Palythoa grandiflora (Caribbean)
11. Polyps generally connected to several other polyps at base, tentacles appear curled—12.
12. Polyps are large and are brown or green in color but lack florescence—Palythoa grandis (Caribbean)
13. Polyps contain green florescent protein or display some other florescent coloration— Palythoa sp. “singapura” (Indo-Pacific).
Here’s a cool key
