From Abundance to Extinction: Evolutionary History of European Aedemonini (Curculionidae) with a Description of the First Representative from Rovno Amber

Round 1

Reviewer 1 Report

The authors provide a taxonomical review of the European Aedemonini tribu, as well as they identify one fossil weevil holotype preserved in amber. This laborious task may help understand the ecological evolution of the large Curculionidae family.

In addition, they include a simple but interesting key to identify species of fossil Aedemonini.

Therefore, I suggest to accept it for publishing.

Author Response

Thank you!

Reviewer 2 Report

Morphologically, the Aedemonini are identified by the peculiar structure of their rostral channel, which is formed partly by a cavity of the mesoventrite and anteriorly by lateral ridges of the pronotum, both in front and behind the procoxa. The illustrations do not show this character. Instead, this body part appears obscured by preservation artefacts. The authors also mention ventrally sulcate femora as a diagnostic character of the genus Electrorhinus. This character does not fit well into Aedemonini. The representatives of Aedemonini I just checked have rounded, non-sulcate femora. However, many Cryptorhynchini have sulcate femora. Unless the character of an Aedemonini-style rostral receptacle has been confirmed and illustrated (maybe possible by µCT) I am somewhat reluctant to see sufficient evidence for this placement. The described species may belong to Aedemonini; it may just as well (or even more likely) be a member of Cryptorhynchini. The situation is similar with the new placement of Korystina Britton. The original illustration looks more like a Camptorhinus, while the description could point to a placement in Aedemonini or Cryptorhynchini. I feel, without additional data / re-examination of the type, this placement in Aedemonini is not justified.

Then, there arises the question, what “domination” (from the title) is? Does this refer to proportion of species relative to other weevil species at the time? Or, does this refer to ecological dominance, i.e. number of individuals in an ecosystem? In any case, in Baltic amber Aedemonini appear too rare (if present at all) to speak of “domination”. The same holds true for the London clay: since these fossils have been accumulated in water, there is likely a bias towards specimens that float / are robust enough not to get destroyed before being embedded. Quite different taphonomy from amber. This would need to be taken into account to arrive at ecological conclusions.

All in all, I am not convinced of this story, based on the weak evidence presented.

Here a few more minor suggestions:

lines 416-417: “Aedemonini make up 28% of the London clay weevils identified to the genus level…” does this refer to the number of specimens or the number of species?

Line 2: “Geological history of European Aedemonini” You could say “paleontological record of” or “evolutionary history of” a group of animals. But “Geological history” would rather refer to a continent, or a geological structure.

line 404: “Fossil Molytinae is presented by” should be “Fossil Molytinae are represented by”

line 405: “Chili” should be “Chile“

lines 415-416: “fossil records were all made” should be “fossil records have all been deposited”

line 451: “threedimensional” should be “three-dimensional”

line 499: say “weaver ant genus Oecophylla” to clarify the placement to the general reader

pages 11-12 of the discussion describing the flora of the London clay appears disproportionate to the discussion of Aedemonini.

Author Response

Morphologically, the Aedemonini are identified by the peculiar structure of their rostral channel, which is formed partly by a cavity of the mesoventrite and anteriorly by lateral ridges of the pronotum, both in front and behind the procoxa. The illustrations do not show this character. Instead, this body part appears obscured by preservation artefacts. The authors also mention ventrally sulcate femora as a diagnostic character of the genus Electrorhinus. This character does not fit well into Aedemonini. The representatives of Aedemonini I just checked have rounded, non-sulcate femora. However, many Cryptorhynchini have sulcate femora. Unless the character of an Aedemonini-style rostral receptacle has been confirmed and illustrated (maybe possible by µCT) I am somewhat reluctant to see sufficient evidence for this placement. The described species may belong to Aedemonini; it may just as well (or even more likely) be a member of Cryptorhynchini. The situation is similar with the new placement of Korystina Britton. The original illustration looks more like a Camptorhinus, while the description could point to a placement in Aedemonini or Cryptorhynchini. I feel, without additional data / re-examination of the type, this placement in Aedemonini is not justified.

- Baltic amber types and the new species were re-examined. All of them are characterized by a channel on the postcoxal portion of the prosternum bounded by carinae. Their femora are weakly sulcate. We looked through specimens of this tribe from Africa and the Oriental region. Some species from Thailand have weakly sulcate femora.

We agreed that the transfer of the genus Korystina to the tribe Aedemonini is premature and a re-study of the type is required.

Then, there arises the question, what “domination” (from the title) is? Does this refer to proportion of species relative to other weevil species at the time? Or, does this refer to ecological dominance, i.e. number of individuals in an ecosystem? In any case, in Baltic amber Aedemonini appear too rare (if present at all) to speak of “domination”. The same holds true for the London clay: since these fossils have been accumulated in water, there is likely a bias towards specimens that float / are robust enough not to get destroyed before being embedded. Quite different taphonomy from amber. This would need to be taken into account to arrive at ecological conclusions.

All in all, I am not convinced of this story, based on the weak evidence presented.

- Insects from the London CIay drifted out to sea with wood (Rundle et Cooper 1971)  This is further supported by the presence of numerous flightless larvae (Jarzembowski, 1992), together with beetles with their elytra in the rest position. Bognor remains the principal international source of pyritized insects, so the absolutely correct opinion of the reviewer concerned the fossils accumulated in water couldn't be applied for London Clay insects. 28% of all curculionid specimens in the ecosystem is prevalence, if not the domination, and we changed the title accordingly. And we absolutely agree that  Aedemonini appear too rare in the Baltic amber - it is just the case. 

Here a few more minor suggestions:

lines 416-417: “Aedemonini make up 28% of the London clay weevils identified to the genus level…” does this refer to the number of specimens or the number of species? Specimens – It was done

Line 2: “Geological history of European Aedemonini” You could say “paleontological record of” or “evolutionary history of” a group of animals. But “Geological history” would rather refer to a continent, or a geological structure. – It was done

line 404: “Fossil Molytinae is presented by” should be “Fossil Molytinae are represented by” – It was done

line 405: “Chili” should be “Chile“– It was done

lines 415-416: “fossil records were all made” should be “fossil records have all been deposited” – It was done

line 451: “threedimensional” should be “three-dimensional” – It was done

line 499: say “weaver ant genus Oecophylla” to clarify the placement to the general reader  – It was done

pages 11-12 of the discussion describing the flora of the London clay appears disproportionate to the discussion of Aedemonini. – It was done

Author Response File: Author Response.doc

Reviewer 3 Report

Please correct: 1) the title of the manuscript, 2) mental shortcuts and respond to the reviewer's comments, remarks, corrections and suggestions. Details in the "clouds" of the reviewed text in the attached file with the ending "...REV". After the indicated corrections, the manuscript is suitable for publication in "Diversity".

Comments for author File: Comments.pdf

Author Response

Please correct: 1) the title of the manuscript, 2) mental shortcuts and respond to the reviewer's comments, remarks, corrections and suggestions. Details in the "clouds" of the reviewed text in the attached file with the ending "...REV". After the indicated corrections, the manuscript is suitable for publication in "Diversity".

– It was done

Author Response File: Author Response.doc

Round 2

Reviewer 2 Report

Improved version looks much better - thanks for your efforts.

Author Response

Thank you!