(Before I get to my comments on this manuscript, I would like to note that I have not reviewed an earlier version of this manuscript. In trying to remain unbiased, I only read through the main comments made by the Editors and the two Reviewers in the previous round of review after I wrote down my main comments.)

In this study, the authors investigate the effect of species coexistence on phenotypic variation of sexual and non-sexual traits in often co-occurring species of newts across Europe. The results indicate that some traits converged in sympatry (notably dorsal and caudal coloration), possibly related to local adaptation or phenotypic plasticity in both species. However, the authors also found evidence for divergence in sympatry in some variables associated with sexual coloration, indicative of reproductive character displacement. Because the data are derived from wild-caught individuals, the phenotypic variation documented also includes an environmental component. By including bioclimatic variables and a local environmental variable, the authors contrast the expected phenotypic distribution (based on species-specific phenotypic plasticity) with the observed level of convergence or divergence.
This study stands out by combining an interesting and relevant evolutionary question with large geographical sampling and the measurement of many different sexual and non-sexual traits in the field. In principle, I think that this study should thus be of interest to evolutionary ecologists. However, I have two major comments.

1) Evolutionary trait divergence or convergence is typically assessed using common garden designs (or any other ‘genetic’ assessments). The authors use a different route and statistically account for environmental variation in their descriptive data. I think this approach is fine, albeit it is critical for the interpretation to thoroughly demonstrate that the variables included in the statistical analysis capture the main environmental components. While the manuscript does this to some extent, it also hints at other environmental variables that could not be accounted for. This includes substrate coloration and the presence of predators, both of which have been shown to elicit strong plastic responses in coloration (and other traits) in other species. Because the interpretation hinges on whether most relevant local environmental conditions have been taken into account or not, I think a more careful discussion of these drawbacks would be appropriate.
For instance, is argued in the Discussion (lines 492-511) that convergence is likely caused by shared plastic responses to environmental variables not measured in this study. However, in the next paragraph, the authors argue that divergence in ventral coloration is likely to represent evolved character displacement because the effects remain significant after accounting for environmental variables. If the variables used to account for environmental variation do not capture then main ecological conditions (as argued in the preceding paragraph), then the conclusion that character displacement is likely seems problematic. It, to me, further implies that divergence could as well be driven by species-specific plastic responses to unmeasured variables.
I therefore think a more carefully articulated discussion would help readers unfamiliar with newt biology to assess how likely it is that these patterns are evolved, rather than driven by environmental variation.

2) The description of some of the analyses was difficult to follow. It was, for instance, unclear to me how body size variation was accounted for. I assume snout-to-vent length was used as body size estimate (although this is not mentioned in the manuscript). However, on line 188, snout-to-vent length is referred to both as a morphological character as well as a body size estimate used for standardization. It was also not clear how body size was accounted for in the context of the PCA described on line 186. Was body size variation removed prior to PCA? Or was the PCA run in a way that controls for most of the overall size variation? Or were residual PC scores used for further analysis? It would also help mentioning the size-correction later when models are described and discussed.

minor comments:
line 38: variation (not variations)
line 79ff: traits involved in resource acquisition such as size or morphology of the feeding apparatus, provides (delete a) powerful support for…
line 268: It is not immediately clear to be why convergence/divergence cannot be inferred from an interaction? Would the sign of the parameter estimates not suffice?
Throughout: The variable describing sympatry/allopatry is initially introduced as “context”. For consistency, I therefore suggest sticking to ‘species-by-context’ interactions, not ‘species-by-sympatry’ interactions.
First paragraph of Discussion: Here, I suggest mentioning that there were specific patterns associated to sexual vs. nonsexual traits. This only hinted at now by mentioning that the patterns depend on the body region investigated, but I think this could be made more explicit. I consider this a major finding and one of the strengths of this study.
Line 526: Couldn’t the observation that there are very few hybrids in the field also suggest particularly strong hybridization avoidance?