This is a systematic analysis of bioluminescence phenomena in Anthozoa combined with field collection data, and the results show a plausible scenario that bioluminescence arose in MRCAs of Octocorallia and was lost in some lineage. The bioluminescence could arise for detoxification and be maintained in the current species for interaction with other species.
Some revisions will help the clarity of this research:
(1) Add a supplementary figure that shows the proportion of bioluminescent octocorals with depth distributions. Although the counts and depth distribution have been drawn in Fig2, it is clearer that using proportion when you explain the octocorals is overwhelmingly bioluminescent at depths greater than 2000 m in Line250-257.
(2) Please add a label of the 542 Ma in Fig1 because it is important in your main results in which the origin of bioluminescence in Octocorallia.
(3) Is there any typo, mislabeling or miscalculated in Line278 the “The ancestral state of the order Malacalcyonacea, which diverged approximately 440 Ma” and “The ancestral state for the order Scleralcyonacea (460 Ma CI: 376-542 Ma) ?
The Fig1 and Fig3 both show the ancestral state for the order Scleralcyonacea is younger than ancestral state of the order Malacalcyonacea.
If this is my misunderstanding, please label it clearly in Fig.

(4) Iine 107, “Thus, for bioluminescent taxa inhabiting shallow depths, we
hypothesize that bioluminescence evolved before shallow-water colonization. ” What do you mean “shallow-water colonization” ? Do we know the timing of shallow- or deep-water colonization?
Maybe rephrase this sentence.

(5) In Fig3. Some explanations are missing. Purple for Malacalcyonacea? Red for scleralcyonacea?
(6) About the limitation of detecting bioluminescence in Line 343, list the methods for detecting the trait in those species discussed in this study. Because the sensitivity of each method is different. For instance, different sensitivity of the camera, naked eye, luminescent machine, or sequence survey.

(7) Please check the grammar or typo again. Some minor revisions:
Line 282 “However, unless bioluminescence was lost early on in Malacalcyonacea,”, remove “on”
Line89: (i.e., scyphozoans, hydrozoans, ctenophores) => “and” ctenophores