Two New Species of Tricoma (Tricoma) (Nematoda: Desmoscolecidae) from Korean Subtidal Sediments, with Notes on Labial Ultrastructure^†

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is a very meaningful research paper. It describes and illustrates two new species of the genus Tricoma using detailed observations from light and scanning electron microscopy. The descriptions and illustrations are very good. The discussion is sufficiently comprehensive, and the conclusions are very clear.

Line 29-31: Suggest deleting the follow three lines in Abstract.

“Although superficially similar to T. (T.) setosa Soetaert & Decraemer, 1989, the new species differs in the number of main rings, head morphology, configuration of somatic setae, and copulatory structures.”

Line 35: “Desmoscolecidae” is changed to Desmoscolecida.

Line 217: 345, relationship is changed to Relationship.

Figure caption:

Figure 1, 6: Add “Line drawings of…”

Figure 2-4, 7-8: Add “Scanning electron microphotographs of…”

Figure 5, 9: Add “DIC microphotographs of …”

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors describe two new species of Tricoma found off Korean Waters. They provide adequate background history of the genus being studied and provide in-depth taxonomic (morphological) accounts to back up their claims. There are many species belonging to the genus Tricoma, but the two new species belong to subgenus Tricoma (Tricoma), allowing authors to compare the new species to reasonable number of potentially close species. I have left main comments within the pdf, but there are several concerns which must be addressed before the paper can be accepted for publication.

1. Methods section, especially regarding SEM prep requires much more details.
2. Labels on the SEM figures must be fixed so that it is more readable.
3. While the morphological analysis conducted by the authors are of high quality (good illustration, inclusion of SEM and micrograph figures), the authors did not include molecular analysis (18S/28S rRNA sequence and consequent phylogenetic analysis). While Tricoma does in fact have limited sequences available online for any meaningful comparative analysis, it would be a step to the right direction to include molecular sequences of these supposed new species, so that the foundation for future analysis can be established. It is highly encouraged for the authors to attempt obtaining molecular sequences of future descriptions if possible.
4. In its current state, there are some parts of the manuscript which feels redundant/repetitive. Some are marked within the pdf, but the authors should go over the manuscript once more to reduce these repetitive sections.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The Manuscript ID: jmse-4029526 addresses identification of two new species of Tricoma (Tricoma) (Nematoda: Desmoscolecidae) from Korean subtidal sediments, with notes on labial ultrastructure and somatic setae diversity. The main question addressed by the research was clear in terms of offering a detailed description of 2 new species of Tricoma. The topic is quite relevant to the journal field as it provides additional fauna to marine nematodes. Compared with other published material, this paper offers broaden understanding of Tricoma diversity in the northwestern Pacific. The ultrastructure of the labial region emphasizes additional morphological variation within Desmoscolecidae. Both DIC and SEM analyses provide important diagnostic characters for species-level discrimination. Although the methodology of the study is classical, additional and updated techniques should have enhanced its solidity and rigor.
It is an interesting article on novel characterization of such two new species. However, some notes to improve the paper are as follows:
1)
The methodology of the study is relatively classic, additional and updated techniques should have enhanced its solidity and rigor. Clearly, upgrading these methods generally remains inevitable. This is especially important as polymerase chain reaction (PCR)-based techniques can be incorporated to offer more accurate, distinct, and reliable identification of the two new species.
2)
Likewise, a few modern devices and tools could be used to precisely isolate, count, identify, and separate such microorganisms in a high-throughput, high-resolution, non-destructive, and reproducible manner; for example: https://doi.org/10.1016/j.bios.2022.114417
3)
If the authors are not able to satisfy the two above-mentioned terms, they should at least discuss their usage and benefits for such identification procedures.
4)
In the text, before abbreviations, related phrases should be written in full (should be spelled out in full at first mentioning). For example, “based on detailed Differential Interference Contrast and Scanning Electron Microscope analyses.” instead of “based on detailed DIC and SEM analyses.”, …etc..
5)
It seems to me that Table 3 was mentioned in the text before Table 2; it is better to take care of the order of tables in the text, if possible.
Therefore, I would suggest accepting it after minor revision.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf