Review Reports

Round 1

Reviewer 1 Report

This is a good quality manuscript and the findings of the study seem sound. I recommend a number of grammatical changes, and suggest some additions to the manuscript. I strongly recommend that these changes are followed in order to improve the clarity of the text and transparency of the research.

 

The Introduction should mention early on that locomotion is the main vital activity of interest.

 

A sampling table should be added to the Introduction or the Description of the traces, or a new Methods section. The table should specify the number of composite trace fossils per study genus, as well as the provenance and age estimate for each fossil. The table could also briefly list each vital activity observed.

 

The Conclusions section contains a list of points, which should be remade into a paragraph.

 

The authors frequently omit a noun at the start of the sentence, typically when using ‘This’ at the start of a sentence. In doing so, the authors are expecting a reader to supply an implied noun from the previous sentence, and in many cases this is not at all obvious. The authors should include a noun in every sentence so that the topic is clear.

I provide an examples of such lines below:

Line 28: “they” Line 34: “their” Line 43: “They”, i.e. change to “These genera” Line 133: “They” – this is especially confusing Line 134: “This” – this is especially confusing Line 139: “This” Line 149: “This” Line 265: “This” Line 328: “This”

Additionally, sentences should not start with ‘and’, which affects the lines listed below:

Line 34 Line 51

Further comments by line:

Line 30: “lifeform” is one word, not two. Line 33: I suggest changing “vital activity” to “vital or biological activity” here. Line 39: Please provide the time range for the Vendian, perhaps specifically for the deposits from European Russia and southern Australia. Figure 1: Is there a way to reformat the figure so that the letters flow directionally from A – G? I appreciate that effort has been made to make the images fit within a rectangle, but it is confusing that d comes before c. Figure 1, Line 69: instead of using a question mark, I suggest saying: “…(perhaps the organism had move from the bedding plane into the overlying sediment)…” Line 71: “The composite imprints” needs to be clarified – does this refer to only composite imprints of the three study genera, or does it also include other organisms? Line 72: Please provide time range for Late Precambrian. Line 75: Please clarify what is meant by “heterogenous” in this sentence, or rephrase. Line 80: Please explain evidence and cite literature for the microbial textures. Line 87: I would use a more speculative tone here, i.e. “…remains that are hypothesized to not be directly related to food gathering.” Line 95: “creeping structure” is vague, please rephrase and clarify meaning here. Line 97: I recommend using a more speculative tone, i.e. “which the animal is believed to have repeatedly passed over the microbial mat during food gathering.” Lines 105-106: “only by analysing the pattern of the distribution of the feeding grooves over the surface area” does not really make sense. Please rephrase this sentence. I think the authors are trying to state that the pattern and distribution of grooves in the trace fossil indicate that Kimberella could move? Lines 107-110: I recommend explaining in a short sentence what the resting trace of Kimberella looked like. Line 139: It would be interesting to know the length of these imprint chains. Line 135: I would modify this sentence to make it clear what is meant by a ‘deep impact’. Be specific. Line 145: Change “arms’ tentacles” to “tentacle arms” or “tentacles.” Line 148: Please clarify what the “linear structures” are. Are these the radial grooves and ridges previously described, earlier in the paragraph? Line 149: Change to “This [noun] potentially indicates…” Line 263: Please rephrase this sentence as it is confusing. Line 263: Please define “detalization” or rephrase, not sure what this means. Line 265: Change “means” to “indicates”, in order to adopt a more speculative tone. Line 293: I recommend clarifying this sentence, changing it to “The fact that the shield imprint of the sole Tribahidium specimen is slightly larger than the trace…” Line 306: I am not sure what is meant by “of a different genesis”. Do the authors mean that these grooves were likely made by a different biological process? Lines 327-328: I am confused what is meant by the second half of this sentence. What is demonstrating an ability? Please rephrase.

Author Response

The authors are grateful to the Reviewer for helpful and constructive comments. Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This is very well written and important paper on the traces associated with certain Ediacaran body fossils. I liked the paper very much and suggest a rapid publication. I would also suggest to explore an alternative scenario for formation of described traces. Could these rare traces be tool marks or scratch marks made by dead animal or living animals which were carried by water currents along the bottom? For references and cases see: Vinn, O. and Toom, U. 2016. Rare tool marks from the Upper Ordovician of Estonia (Baltica). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 281, 221-226.

Best wishes,

 

Author Response

The authors are grateful to the Reviewer for helpful and constructive comments. Please see the attachment.

Author Response File: Author Response.pdf