Magelonidae Cunningham & Ramage, 1888 (Annelida, Polychaeta)—Worldwide Identification Keys and the Re-Establishment of Maea Johnston, 1865

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors presented a very thorough historical taxonomic account of the Magelonidae group which is very essential in the current taxonomic climate. The authors provided detailed accounts, an appropriate key and great visuals to enrich the taxonomic guide which is important when taxonomists are declining and the need for non-specialists to conduct identifications are becoming prevalent. However, in some cases, it would have been desirable for the authors to include figure references to some of the key characteristics mentioned in the dichotomous key to help gravitate readers to what is actually being discussed. These terms can be confusing even to a polychaete taxonomist that focuses on different families. The authors should consider at least including figure references to things like mucronate chaetae, crenulate chaetae/prostomium etc.  

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Some of the english can be improved. comments are made although not extensive. 

Author Response

Reviewer	Comments	Edit made
1	It would be desirable for the authors to include figure references to some of the key characteristics mentioned in the dichotomous key.	References have been made in the text as requested by the reviewer. However, as we don’t have images for every species included in the key, it could cause confusion to refer readers to a specific figure which is of another species. Nonetheless, we do agree with the reviewer on how important it is to help readers visualise characters. Therefore, we have added references at the start of the key for Figures 1 and 2 which show all morphological characters and have additionally improved Figure 2 to include labels of all of the morphological characters to help readers interpret the structures. We have additionally added figure references to all morphological characters in Table 1.
	Edits throughout document	All edits have been made as requested
	When constructing phylogenetic trees, the outgroup must always be in the basal position, i.e., at the bottom of the tree to show evidence of derived taxa from that outgroup which serves as the most recent common ancestor for the ingroup taxa.	It has been argued that outgroups determine the contrastive form of our why-questions (see, https://doi.org/10.1111/j.1463-6409.2006.00229.x). However, as the reviewer correctly noted, the phylogenetic tree originates from previously published work and therefore cannot be modified in the present manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

this is a very well written manuscript with nice figures and a much needed key to species. I do have some comments, see below, of which my biggest concern is if your next manuscript (47 in your reference list) is going to change any of the names in this key, and thus render it very difficult to use in the future.
Comments:

Page 3 - in Figure 1 and Figure 2 figure texts, all the taxa are labelled with ”M. …” Since this paper is about re-erecting another genus that also begins with an M, it would be good to always write out the whole genus name. It only states ”Magelonid morphology”, and with this manuscript, Magelonidae is no longer monotypic.

Page 5 - regarding reference 47 - according to the reference title, it seems the reference only contains Magelona, not Magelonidae (...”within the family”). More importantly, as I understand it, more genera need to be erected within Magelonidae in the future if the authors follow the tree in Figure 6 and use that among other things to justify the re-erection of Maea. If the different groups in this manuscript would be allocated to different genera in the future reference 47, maybe it would be good to change the publication order and get ref. 47 out first, as many of the names used in this much needed taxonomic key might change (as I understand it. Sorry if I have misunderstood this).

Page 5 - First sentence of ”Principle taxonomic work…”: says that the content of Table 1 is "Key taxonomic contributions and revisions”, Table 1 contains useful morphological characters. Table 2 on the other hand would fit better here.

Page 5 - In same part, next paragraph - reference 43 seems to be unpublished, should it be included here if it’s not publicly available?

Page 6 - in paragraph starting with ”A series of papers…” later down says ”…highlighted in Table 2” - should be Table 1?

Page 11 - in the Thorax part, I don’t really understand how figure 2R can show both entire absent superior dorsal lobes AND those lobes occurring on some or all thoracic chaetigers. Maybe it would be useful with arrows also in this figure (as in Figure 1), pointing at the important characters?

Page 11 in Chaetae part - discussions is misspelled. Furthermore, no figure number in (Figure L-M)

Page 13 first sentence ”…may be absent”, and Gender misspelled in ”Gener: Feminine”

Page 19 and onwards - all taxa in the key is listed as ”M. …”, but in the list for Figure 7 they’re named either Magelona or Maea. I suggest the full genus name is written out everywhere in the key (as it is under the Western Indo-Pacific key, although there using Magelona all over and ignoring the Maea species from Figure 7) to avoid confusion.

Page 21 - under point 15. in first statement says ”chaetiger nine” and in second statement ”chaetiger 9”. Not very important, but good to be consistent.

Under Remarks it says Magelona sachalinensis, but again, in the list of Figure 7 there’s Maea sachalinensis.

Table 1 - characters to detail in descriptions: Burrowing organ Everted/not everted? Is it species dependent if the worm evert the burrowing organ upon death or not?

Author Response

2	Biggest concern going forward is if names in this key are likely to change and thus render it very difficult to use in the future.	It is probable that additional genera within Magelonidae will be established in the future; however, those revisions remain some way off. Taxonomic progress takes time yet reliable identification tools are required in the interim to support ongoing research and species recognition. For this reason, we considered it essential to complete and provide this resource at the present time.
	It is confusing as both genera begin in M, as to which genus is being referred to.	We agree with the reviewer and a similar comment made by one of the other reviewers. Therefore, we have ensured that genus names are written in full through the manuscript.
	Table 1 and Table 2	As pointed out by the reviewer the citations of the tables in the text were the wrong way around and this has been corrected.
	Reference 43 seems to be unpublished should it be included here if it is not publicly availably?	Brasil (2003) is a thesis, and as such should be available from the University. Additionally, this work is an important resource for work on the Magelonidae and therefore the authors feel it is vital that it is included.
	Table 1: burrowing organ everted/not everted, is it dependent if the worm everts it upon death or not	Yes, the most important character to record is the shape and any ridges. We have adapted the text to make that clear.

Reviewer 3 Report

Comments and Suggestions for Authors

General comments

The paper by Mortimer et al. represents a comprehensive state-of-the-art regarding the current taxonomic knowledge of the family Magelonidae. While emphasizing the recent substantial advancements in species delineation, authors show a still uneven geographic coverage of taxonomic studies that hamper a worldwide revision of representatives of this group. Of real help in addressing this latter taxonomic challenge is the provision of a standardized framework for morphological characterization of magelonids. Based on morphology and phylogenetic data, the authors resurrect the genus Maea Johnston, 1865. The identification keys for all currently recognized species of magelonids presented in the paper in two formats (a dichotomous key by marine biogeographic realms and a pictorial key) are intended to serve as useful tools for reliable identification of shovel head worms across the globe. The paper also envisages further research to be carried to overcome the still insufficient taxonomic resolution within the group. 

 

Specific Comments

Though the authors reinstate the genus Maea, there is no a separate dichotomic key to species of this genus. In the dichotomic key they are treated together as one genus, what is confusing. The confusion is amplified in the first part of the key where the generic names are abbreviated to M. and the reader don't know whether the authors refer to Magelona or to Maea. Therefore, I suggest to provide a key to both genera and then provide separate identification keys to species within each genus. Also, it is pity that some of the images on the plates (especially those illustrating chaetal morphology) that might be important in accurate identification are too small to be visualized.

Some minor edits have been made directly in the manuscript.

Final comments

In my opinion, the study represents an excellent model for how taxonomy should be conducted. I commend the authors on their valuable and comprehensive work, and I believe this paper will serve as an important resource for the scientific community.

Comments for author File: Comments.pdf

Author Response

3	Suggestion to provide dichotomous keys for both genera to avoid confusion, particularly as both genera start with the letter M.	As the dichotomous key is broken down into marine realms, the resulting keys for Maea in many areas would end up with only one species. Additionally, users who are not familiar with magelonids may not know which genera key they need to start with. However, we do agree with the reviewer that it is particularly confusing as both genera start with M, therefore we have gone through the whole key and ensured that the genus is written out in full to reduce this confusion.
	Some of the images could be larger.	Given the large number of figures required for inclusion in the manuscript, their dimensions were reduced to ensure appropriate layout and formatting. Nevertheless, the underlying image resolution is sufficient to allow clear visualisation when examined at higher magnification on screen
	Minor edits made directly in the manuscript	All edits have been made
	Final comments	The authors would like to thank the reviewer for their comments

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,
thank you for clearing up some of my questions before, and again, my compliments on the beautiful worm pictures.
I still have a problem though:

In my previous review I suggested that the phylogeny sorting out Magelona into possibly new genera should be published before this key. I understand that the authors see this in the future, but there is a problem phylogenetically with erecting a genus within the Magelona clade as pictured in the tree figure, re-naming one clade to Maea and yet still call all the surrounding taxa Magelona.

My suggestion would be to either re-name the groups discussed in this ms into proper genera OR to wait with the re-erecting of Maea until all the groups can be sorted, to avoid making Magelona paraphyletic.

Author Response

"In my previous review I suggested that the phylogeny sorting out Magelona into possibly new genera should be published before this key. I understand that the authors see this in the future, but there is a problem phylogenetically with erecting a genus within the Magelona clade as pictured in the tree figure, re-naming one clade to Maea and yet still call all the surrounding taxa Magelona." - Following the reviewer's comment we have revisited and updated Figure 6 to make the current situation clearer. We have removed the annotations, so that it is clear that Maea is not within the Magelona clade. We appreciate the reviewer's comment.