Transfer Alert

This paper was transferred from another journal. As a result, its full editorial history (including decision letters, peer reviews and author responses) may not be present.

PONE-D-22-08636A novel endocast technique providing a 3D quantitative analysis of the gastrovascular system in Rhizostoma pulmo: an unexpected through-gut in CnidariaPLOS ONE

Dear Dr. Avian,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

Both reviewers found your study imformative and technically sound, but they have raised a number of important points that you will need to address satisfactorily. Particular attention should be paid to what findings of your study are novel and which ones were already known.  You also need to avoid overstating the impact of your findings, as pointed out by Reviewer 2.  ==============================

Please submit your revised manuscript by Jun 02 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Robert E. Steele, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at 

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and 

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. In your Methods section, please provide additional information regarding the field permits you obtained for the work. Please ensure you have included the full name of the authority that approved the field site access and, if no permits were required, a brief statement explaining why.

3. Thank you for stating the following financial disclosure: 

"The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."

At this time, please address the following queries:

a) Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution. 

b) State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

c) If any authors received a salary from any of your funders, please state which authors and which funders.

d) If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

4. We note that Figure 12 in your submission contain [map/satellite] images which may be copyrighted. All PLOS content is published under the Creative Commons Attribution License (CC BY 4.0), which means that the manuscript, images, and Supporting Information files will be freely available online, and any third party is permitted to access, download, copy, distribute, and use these materials in any way, even commercially, with proper attribution. For these reasons, we cannot publish previously copyrighted maps or satellite images created using proprietary data, such as Google software (Google Maps, Street View, and Earth). For more information, see our copyright guidelines: http://journals.plos.org/plosone/s/licenses-and-copyright.

We require you to either (1) present written permission from the copyright holder to publish these figures specifically under the CC BY 4.0 license, or (2) remove the figures from your submission:

a. You may seek permission from the original copyright holder of Figure(s) [#] to publish the content specifically under the CC BY 4.0 license.  

We recommend that you contact the original copyright holder with the Content Permission Form (http://journals.plos.org/plosone/s/file?id=7c09/content-permission-form.pdf) and the following text:

“I request permission for the open-access journal PLOS ONE to publish XXX under the Creative Commons Attribution License (CCAL) CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). Please be aware that this license allows unrestricted use and distribution, even commercially, by third parties. Please reply and provide explicit written permission to publish XXX under a CC BY license and complete the attached form.”

Please upload the completed Content Permission Form or other proof of granted permissions as an "Other" file with your submission.

In the figure caption of the copyrighted figure, please include the following text: “Reprinted from [ref] under a CC BY license, with permission from [name of publisher], original copyright [original copyright year].”

b. If you are unable to obtain permission from the original copyright holder to publish these figures under the CC BY 4.0 license or if the copyright holder’s requirements are incompatible with the CC BY 4.0 license, please either i) remove the figure or ii) supply a replacement figure that complies with the CC BY 4.0 license. Please check copyright information on all replacement figures and update the figure caption with source information. If applicable, please specify in the figure caption text when a figure is similar but not identical to the original image and is therefore for illustrative purposes only.

The following resources for replacing copyrighted map figures may be helpful:

USGS National Map Viewer (public domain): http://viewer.nationalmap.gov/viewer/

The Gateway to Astronaut Photography of Earth (public domain): http://eol.jsc.nasa.gov/sseop/clickmap/

Maps at the CIA (public domain): https://www.cia.gov/library/publications/the-world-factbook/index.html and https://www.cia.gov/library/publications/cia-maps-publications/index.html

NASA Earth Observatory (public domain): http://earthobservatory.nasa.gov/

Landsat: http://landsat.visibleearth.nasa.gov/

USGS EROS (Earth Resources Observatory and Science (EROS) Center) (public domain): http://eros.usgs.gov/#

Natural Earth (public domain): http://www.naturalearthdata.com/

5. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Table 2 in your text; if accepted, production will need this reference to link the reader to the Table.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This paper is novel and the findings provide important implications to the study of micro-anatomy and differential development of function and organ system in cnidarians. The method in this paper is obviously important for the related research in the future, I, therefore suggest to publish. Below are some concerns to be considered maybe in the revised manuscript or reply to reviewers.

I really like the novel method to endocast the jellyfish. I think this method could be applied to study other transparent or translucent animals not just jellyfish, e.g. ctenophores. However, I have some comments on the "a through-gut" of Rhizostomeae. As the authors stated: "The inflow involves only the “mouth” openings on the internal wing of the oral arm and relative inner hemi-canals while the outward flow involves only the two outermost wings’external hemi-canals and relative“anal”openings on the external oral arm. "; and indeed the innovative method clearly shows the double-direction of water flows. However, the author should firstly discuss this topic within the scope of cnidarians and then extend to the bilaterians, and then we will have a better understanding of the origin of such double-direction flows in jellyfishes. The double-direction water flows (in and out) driven by gastric cillia in siphonoglyph, are well known in gastric cavity of anthozoans. The hemi-canal flows, equivalent to the roof and floor flows, are well known in other jellyfishes. The radial canals seen in living jellyfishes, however, were absent in Cambrian benthic medusozoans (Han et al., 2016; Wang et al., 2017), and were most probably derived from the reduction of broad gastric pouches by closing of endoumbrella and exumbrella(endodermic perradial fusion in Han et al., 2016). The arm canals of Rhizostomeae, were developed from the closure of the oral groove. Thus the "through gut with oral anus", is not strange in cnidarians and should be a specialized structure independently acquired in Rhizostomeae.

Han, J., Kubota, S., Li, G.X., Ou, Q., Wang, X., Yao, X.Y., Shu, D.G., Li, Y., Uesugi, K., Hoshino, M., Sasaki, O., Kano, H., Sato, T., Komiya, T., 2016. Divergent evolution of medusozoan symmetric patterns: Evidence from the microanatomy of Cambrian tetramerous cubozoans from South China. Gondwana Research 31, 150-163.

Wang, X., Han, J., Vannier, J., Ou, Q., Yang, X., Uesugi, K., Sasaki, O., Komiya, T., Sevastopulo, G., 2017. Anatomy and affinities of a new 535-million-year-old medusozoan from the Kuanchuanpu Formation, South China. Palaeontology 60, 853-867.

Reviewer #2: In this paper, Avian et al. use resin endocasts to describe the gastrovascular system of the jellyfish Rhizostoma pulmo. The beautiful endocast imagery is paired with detailed morphometric work. It was interesting to see what kind of data could be collected from the endocast, but most of the details are not directly pertinent to the main argument in this manuscript—that there is directional flow in the hemi-canals and therefore a through-gut. Despite the emphasis on novel endocast techniques and 3D X-ray computed microtomography, the main argument is primarily supported by more traditional stain injection experiments (Figures 9-11 and the associated videos). Unfortunately, I was unable to take that data and reconstruct the model the authors provide. I detail my concerns below; if they can address these issues, I would find the paper markedly stronger:

1) I am personally unable to see how the authors go from the photo in Figure 9a to the model in 9b. A photo of comparable parts of the oral arm might help. I watched the associated video but was still unable to tell what data to take from it.

2) Figure 10c is one of the more compelling images. It shows how stain is concentrated in the outer hemi-canal but not the inner hemi-canal. It is unclear though how this image relates to the staining experiments illustrated in Figs. 9-11. Is this part of the same set of experiments? Is it from one of the experiments where the oral arms were cut off? If so, it seems plausible that directional flow could be a behavioral response to tissue damage.

3) Assuming the model proposed here is correct, there is nothing in the manuscript to demonstrate that directional flow in the hemi-canals is related to food digestion. The movement of dye demonstrates how water circulates through the animal, but how important this current is to the intake or excretion of food remains unknown. It therefore feels premature to call these pores “mouths” or “anuses” as the authors do.

4) My next point is a matter of stylistic choice. The authors use strong language to describe the significance of their results, often referring to the blind-gut model of cnidarian anatomy as a “paradigm” or “dogma” they have overthrown. They call their results “astonishing”, with “huge consequences” for our understanding of bilaterian gut evolution. But the authors never explain exactly how this new information from Rhizostoma impacts current hypotheses of bilaterian bodyplan evolution. As the authors note, anal pores have been described in ctenophores as well as the medusozoan Aequorea, so through-guts are not unheard of outside of the Bilateria. Presnell (2016), which is cited several times in this paper, serves as a bit of a cautionary tale. Although Presnell’s description of a through-gut in ctenophores is described in this manuscript as paradigm shaking, anal pores in ctenophores had already been reported by Louis Agassiz in 1850, and some scientists were surprised anyone found Presnell’s finding remarkable (see Tamm, Sidney L. "No surprise that comb jellies poop." Science 352.6290 (2016): 1182-1182). The authors are free to discuss their results in terms they choose, but I think most readers will find these results interesting but far from paradigm shifting.

5) The authors rightly mention that one benefit of their new technique is that “3D X-ray imaging becomes easily sharable in multiple copies all over the world”. In that spirit, I think this paper would be stronger if the authors provided the actual 3D model as a supplemental or otherwise accessible file.

6) One final, minor point. The authors call the Medusozoa “a remarkable homogeneous group.” I cannot think of anything further from the truth. Consider the dramatic differences in body plan between box jellies, siphonophores, and myxozoans, just to name a few!

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Jian Han

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

A novel endocast technique providing a 3D quantitative analysis of the gastrovascular system in Rhizostoma pulmo: an unexpected through-gut in Cnidaria

PONE-D-22-08636R1

Dear Dr. Avian,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Robert E. Steele, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

I am happy to make the decision to accept your manuscript. Note that Reviewer 2 suggests two minor edits to the text. I believe these suggestions clarify the work and ask that you make these edits when you submit the final version of your manuscript. I agree with Reviewer 2 regarding putting your data in a public database, but I will not make this a requirement for acceptance.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: No

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I am satisfied with the authours's substantial revision according to my suggestion, I am glad to see this article published in PLoS One.

Reviewer #2: The changes the authors have made address the concerns that I had. Congratulations on an interesting read!

I would still prefer that the authors make the raw data available on a public database instead of providing it upon request. I will leave it up to the editor to decide what is appropriate in this case.

In addition, I have two minor suggestions that the authors are welcome to accept or not:

1) In the abstract and the discussion, the authors try to nuance their main argument by invoking their specific taxon (i.e. "the gastrovascular system in Rhizostoma...partially invalidates the paradigm (at least for this taxon) of a single oral opening with both the uptake and excrete function"; "...we can partially refuse the bias (at least in this taxon) of a single oral opening with both the uptake and excrete function"). I appreciate the attempt at nuance, but I think this phrasing doesn't quite work, since it is already known that Rhizostomae lack a single oral opening. I think removing the parenthetical will make these sentences clearer.

2) In my initial review, I disagreed with the authors' description of Medusozoa as a "homogenous" group, given the high degree of morphological diversity. The authors countered that the Medusozoa are monophyletic, and wrote a sentence in the paper to state as much ("Regarding gut anatomy and digestive mechanisms, the Subphylum Medusozoa, even if comprising morphologically heterogeneous taxa, from the phylogenetic point of view it is anyway considered monophyletic"). I personally think this sentence reads awkwardly, and would be confusing to a reader who wasn't familiar with our back-and-forth. I certainly never meant to suggest that medusozoans are not monophyletic. Perhaps the following change?:

"The Medusozoa are a monophyletic groups with a wide range of gut anatomies and digestive mechanisms."

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Jian Han

Reviewer #2: Yes: David A. Gold

**********