To increase transparency, PeerJ operates a system of 'optional signed reviews and history'. This takes two forms: (1) peer reviewers are encouraged, but not required, to provide their names (if they do so, then their profile page records the articles they have reviewed), and (2) authors are given the option of reproducing their entire peer review history alongside their published article (in which case the complete peer review process is provided, including revisions, rebuttal letters and editor decision letters).
Thank you for making revisions to your fine paper. I appreciate that you included the conservation evaluation for the species treated in this paper. It is timely, and hopefully it will have a positive impact on the conservation of this enigmatic groups of salamanders.
Thank you for submitting a fine MS to PeerJ. Two of the referees suggested minor revision, while the third referee suggested accept. I have opted for minor revision so that you have the opportunity to implement the reviewers’ suggestions.
In addition to the comments of the reviewers 1 and 2, I would like to see a conservation assessment of each of the newly described species plus Thorius minutissimus and Thorius narisovalis, and a final short section on conservation species of the genus as a whole (or at least species from southern Oxaca). This should not be too much additional work, and although the scope of this MS is taxonomy, the implications of these descriptions and redescriptions together with the field collecting trends and landscape changes are profound for these species. Few people have such extensive and long-term data, thus I think there is also a certain amount of social responsibility of interpreting these data from a conservation perspective and making this information available in a clear form.
This manuscript is well-written and includes the relevant background information and literature, all appropriately referenced.
See my later comments regarding Figure 1 and the legend for Figure 1.
The study is well-designed and contains a variety of evidence, with excellent figures, analyses and discussion of the validity of the species and the evidence for the new species in the context of previous work and new evidence.
I think the declines or possible extinction needs to be emphasized more. Either in the introduction or the abstract, you could mention the proportion of material collected long ago --
Something like "[Nearly all or most or X%] of the specimens analyzed in this study were collected more than X years ago because living specimens have become nearly impossible to find"
Why exclude sp. 2 and sp. 3? I think the paper is fine as it is, but in the conclusions somewhere it would be useful to stress the paradox presented here of the 3 new species presented here, plus [4?] additional ones to be described soon increasing the taxonomic diversity while the species in the wild are in peril.
sp. 4 (longicauda) is not monophyletic in the mtDNA tree in Rovito et al, 2013 - this is mentioned in the text, but I would like to see that the morphology between the 2 localities is not separate in morphospace (Figure 2) - if the 2 populations are discrete, then it needs to be mentioned, if not, that fact should be mentioned.
Figure 1 - What is white versus black symbols inside of the symbols?- this needs to be clear in Figure legend.
The inset is too enlarged to be useful for someone not familiar with Mexican geography.
Is the mintissimus locality the same one as the 2013 one? - They don't match up.
In addition, the legend mentions that T. pulmonaris is not shown, but sp. 2 and sp. 3, and possibly sp. 7 are not shown, but occur on the map. This is important because of the discussion of sympatry and the fact that the map as it is suggests a lack of sympatry for many samples, but sp. 2, and sp. 3 are sympatric with narisovalis.
Figure 2: More discussion and examination of sympatry is needed in the paper:
If character displacement occurs for sympatric species, then the prediction would be that allopatric species can overlap in morphospace, but sympatric forms should be divergent.
Is that true at all? If so, it needs to be mentioned.
T. pinicola overlaps with other species, but is not sympatric with any of them, as would be expected with character displacement.
For the two individuals of longicaudus and tlaxiacus that are similar to each other in morphospace - are these allopatric or sympatric? The same question for narisovalis and tlaxiacus apply.
Even if there is no pattern, this lack of pattern should be mentioned.
The only two changes I see as necessary are:
1) Improve and clarify Figure 1 and
2) an examination and discussion of sympatry as it relates to the individuals shown in Figure 2
Parra - Olea et al. described three new species of Thorius and redescribed two species. The article is well written and I think that the three new salamander species described are new.
The evolutionary characteristic used by the authors to distinguish the new species as well as the diagnostic features and comparisons with other species are well done.
The title: I think it would need to change to be more specific (see comments),
the principal reason of my suggestion is beacuse the authors not access to review all species of the genus under study to said: Taxonomy of minute salamanders (thats mean that you are gonna revised all the species of the genus).
Although based largely on the work of Rovito et al. 2013 for the molecular references, the authors do not report the genetic distances (it would be interesting as evidence) to differentiate species. Also is important report the support the branches obtained by Rovito et al. 2013 in each clade of the species and report which genes were used.
i detected some imprecise terms that need to be improve: e.g. moderate (without mention of measures); long tail (without measure), genetic distances was 0.15 (that mean high or low for the group?; etc..(see the comments)
In addition to the background distribution mentioned by the authors, is necessary to highlight the importance of conservation of these small
organisms. Add a sub part of conservation in each described species would be important to draw the attention of readers.
some paragraphs in the discussion not discuss the results, but rather only tell the taxonomic history of the species ( that should be in redescriptions as remarks).
The authors use morphologic, morphometric, phylogenetic and Osteological characteres to describe the new species.
I think that the experimental design are very complete and the evolutionary tools that were used are efficient and informative
I consider this work important to reveal the hidden species diversity within the genus.
This manuscript provides a very thorough and detailed description of three new species of plethodontid salamander from the genus Thorius, and clarifies the taxonomy and distribution of a fourth species from which the other species are split and described. The authors provide substantial morphological information for these species descriptions, which are backed up by sufficient genetic data. The strength of the genetic evidence comes from previously published allozyme data, which even in an era of genomic sequence data, have substantial information about cryptic species boundaries. The DNA sequence evidence used here is a bit more limited, but is largely in line with the allozyme-based insights. This paper is very well written, especially given the level of detail provided in these descriptions. How many more species of plethodontid salamanders are there to describe? Clearly at least three more.
All text and materials provided via this peer-review history page are made available under a Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.