A new large hypercarnivorous crocodyliform from the Maastrichtian of Southern Patagonia, Argentina

Fernando E. Novas; Diego Pol; Federico L. Agnolín; Ismar de Souza Carvalho; Makoto Manabe; Takanobu Tsuihiji; Sebastián Rozadilla; Gabriel L. Lio; Marcelo P. Isasi

doi:10.1371/journal.pone.0328561

Peer Review History

Original SubmissionJanuary 27, 2025
15 Apr 2025 Decision Letter - Paolo Piras, Editor PONE-D-25-04716A new large hypercarnivorous crocodyliform from the Maastrichtian of Southern Patagonia, ArgentinaPLOS ONE Dear Dr. Pol, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. ============================== Please follow referee's suggestions mainly those about anatomical description and postcranial elements One referee asks, in partuclar, more adherence between descritptions and provided illustrations. A hypothetical life restoration could be of great benefit for the final publication. ============================== Please submit your revised manuscript by May 30 2025 11:59PM. 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Special thanks to Santiago Miner for assistance in scanning and threedimensional modeling of the fossils reported here. Thanks also to Federico Braun for allowing access to his property and Facundo Echeverría and his wife Daphne Fraser (Estancia La Anita) for their valuable help. We thank the Secretaría de Cultura for providing the permits to conduct our projects and explorations in Santa Cruz Province. This research is part of the Argentine-Japanese collaboration, and we thank funding provided by National Geographic Grant NGS 9282-R-22: The End of the Dinosaur Era in Patagonia, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (Faperj E-26/200.998/2024), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq 303596/2016-3). We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. 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We are unable to open your Figure file [Fig 11-textoutline.eps]. Please kindly revise as necessary and re-upload. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: N/A ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: The work is very well written and developed, and the specimen itself is extraordinary for the understanding of Notosuchia, without a doubt. However, some corrections and modifications are necessary to improve the work. I believe that future work focused on the taphonomic aspects of the material will be carried out. However, given the interesting fact that it was found in a concretion, it would be appropriate to report part of the process of discovery, collection and preparation of the specimen, even if briefly. In terms of the morphological description, I felt that more attention should have been paid to the palatal region of the skull, and its elements such as palatines, pterygoid, and ectopterygoids. As for the postcranium, the osteoderms (dorsal dermal shield) have practically not been described. In the discussions, when commenting on the differences in the paleofaunas of the southern and northern Patagonia and Brazil, it should be noted that Barreirosuchus franciscoi is also a broad-snouted taxon of Peirosauria with large body mass. There is also evidence of megaraptors in the southeastern region of Brazil. My comments and suggested changes are highlighted and are included in the attached files. Reviewer #2: I was requested to review the manuscript titled “A new large hypercarnivorous crocodyliform from the Maastrichtian of Southern Patagonia, Argentina” by Novas et al. The manuscript deals with a beautifully preserved new taxon (Kostensuchus) from the latest Cretaceous (Maastrichtian) of Southern Argentina. Besides the good preservation, this new taxon is very large and helps in the knowledge to a clade only known by very partial remains, “broad-snouted” peirosaurids. Furthermore, illustrations of the fossil materials are adequate and contribute to illustrate the specimen. The manuscript is clear and well-written. I made some comments (typos and some incomplete sentences), but those should be considered as suggestions by the authors as I am not a native English speaker. I think after some minor changes the manuscript could be accepted for publication. I mention, briefly some of these (which are minor): 1) Figures should be cited more often in the description. I added some cites to this, but only in the begging. 2) Some cites are missing when comparing the anatomy of Kostensuchus. E.g., “…unlike the condition of most notosuchians”. That should be followed by a cite or at least the mention of some taxa. See the comment (cites) or (e.g., MENTION SOME TAXA) throughout the text. 3) Some particular, even unique features, of Kostensuchus can not be seen in the figures (like the grooves on the premaxilla, mandible, or the lack/change of ornamentation near the antorbital fenestra). I don’t know if that is caused by the poor quality of images, if so label them on the figures. Regarding the unique condition of the lacrimal of Kostensuchus, that could be illustrated in a very simple one-column figure (especially considering it represent an autapomorphy of the new taxon). 4) Add more labels to the figures, in particular to the ones of the posterior view of the skull (some features are described but not marked like the siphonium) and the cervicodorsal block of vertebrae. In the later, if possible add the number of vertebrae (either D1, D2, D3) as it is useful to evaluate some transitions. 5) Finally, a small comment on the humeral anatomy of Kostensuchus. The authors infer a more sprawiling limb orientation during the locomotion of Kostensuchus, mostly based on the anatomy of the ilium. However, some of these features were used as criteria to infer a more parasagittal orientation of the limbs in sebecids and baurusuchians (Riff, 2007; Pol et al., 2012). Contrasting with those taxa, Kostensuchus has a much more robust humerus, which is not common un cursorial parasagittal reptiles. Thus, these features could have other putative functions here (i.e., supporting the weight if the anterior part of the body and head?)? ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy . Reviewer #1: No Reviewer #2: Yes: Juan Martín Leardi ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. 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Attachments Attachment Submitted filename: Review - PONE-D-25-04716.pdf Attachment Submitted filename: Review - Novas et al. - PONE - peirosaurian from Patagonia.pdf Attachment Submitted filename: PONE-D-25-04716.pdf https://doi.org/10.1371/journal.pone.0328561.r001
Revision 1
25 Jun 2025 Author Response Dear Editor, We thank the reviewers and the editor for their thorough evaluation of our manuscript. We have followed all suggestions except those for which we provide detailed response below in bold font: Reviewer #1: The work is very well written and developed, and the specimen itself is extraordinary for the understanding of Notosuchia, without a doubt. However, some corrections and modifications are necessary to improve the work. I believe that future work focused on the taphonomic aspects of the material will be carried out. However, given the interesting fact that it was found in a concretion, it would be appropriate to report part of the process of discovery, collection and preparation of the specimen, even if briefly. Whereas conducting a taphonomic research could be interesting, it lies outside the scope of this work and especially outside our expertise, as we do not have authors capable of conducting a proper taphonomic analysis. However, we follow the advice of the reviewer and we have now included a report on the process of discovery, collection and preparation of the specimen. Given the structure of the manuscript we have decided to include these details in the supplementary information. In terms of the morphological description, I felt that more attention should have been paid to the palatal region of the skull, and its elements such as palatines, pterygoid, and ectopterygoids. We have expanded the description of the palate, especially of the palatines and pterygoids that are better exposed than the ectopterygoids. As for the postcranium, the osteoderms (dorsal dermal shield) have practically not been described. We have included a new paragraph description of the osteoderms In the discussions, when commenting on the differences in the paleofaunas of the southern and northern Patagonia and Brazil, it should be noted that Barreirosuchus franciscoi is also a broad-snouted taxon of Peirosauria with large body mass. There is also evidence of megaraptors in the southeastern region of Brazil. Yes, good points, we have modified the text to emphasize the differences with northern Patagonia rather than with Brazil. Restricting the comparison to northern Patagonia makes also more sense because there is chronostratigraphic control that correlate the Chorrillo and the Allen formations, wheras the correlation with the Baurú Group of Brazil is less precise. My comments and suggested changes are highlighted and are included in the attached files. All changes in the marked-up file have been followed. Reviewer #2: I was requested to review the manuscript titled “A new large hypercarnivorous crocodyliform from the Maastrichtian of Southern Patagonia, Argentina” by Novas et al. The manuscript deals with a beautifully preserved new taxon (Kostensuchus) from the latest Cretaceous (Maastrichtian) of Southern Argentina. Besides the good preservation, this new taxon is very large and helps in the knowledge to a clade only known by very partial remains, “broad-snouted” peirosaurids. Furthermore, illustrations of the fossil materials are adequate and contribute to illustrate the specimen. The manuscript is clear and well-written. I made some comments (typos and some incomplete sentences), but those should be considered as suggestions by the authors as I am not a native English speaker. All changes in the marked up file have been followed. I think after some minor changes the manuscript could be accepted for publication. I mention, briefly some of these (which are minor): 1) Figures should be cited more often in the description. I added some cites to this, but only in the begging. Corrected, we have added more references to figures in the description. 2) Some cites are missing when comparing the anatomy of Kostensuchus. E.g., “…unlike the condition of most notosuchians”. That should be followed by a cite or at least the mention of some taxa. See the comment (cites) or (e.g., MENTION SOME TAXA) throughout the text. Corrected. 3) Some particular, even unique features, of Kostensuchus can not be seen in the figures (like the grooves on the premaxilla, mandible, or the lack/change of ornamentation near the antorbital fenestra). I don’t know if that is caused by the poor quality of images, if so label them on the figures. We have added a new figure (Figure 4) with anatomical details, see below. Regarding the unique condition of the lacrimal of Kostensuchus, that could be illustrated in a very simple one-column figure (especially considering it represent an autapomorphy of the new taxon). We have added a new figure (Figure 4) with anatomical details that were not well illustrated in the original figures. These include the maxillary groove, the lacrimal bulge, the autapomorphic depressed lateral surface of lacrimal, the lack of lacrimal antorbital fossa, and the extension of the jugal towards the antorbital fenestra. 4) Add more labels to the figures, in particular to the ones of the posterior view of the skull (some features are described but not marked like the siphonium) and the cervicodorsal block of vertebrae. In the later, if possible add the number of vertebrae (either D1, D2, D3) as it is useful to evaluate some transitions. Corrected. 5) Finally, a small comment on the humeral anatomy of Kostensuchus. The authors infer a more sprawiling limb orientation during the locomotion of Kostensuchus, mostly based on the anatomy of the ilium. However, some of these features were used as criteria to infer a more parasagittal orientation of the limbs in sebecids and baurusuchians (Riff, 2007; Pol et al., 2012). Contrasting with those taxa, Kostensuchus has a much more robust humerus, which is not common un cursorial parasagittal reptiles. Thus, these features could have other putative functions here (i.e., supporting the weight if the anterior part of the body and head?)? We have revised the relevant sentence to reflect a more nuanced interpretation. It now reads: “This shared feature has been interpreted as likely related to a parasagittal posture [40], but another possibility is that it reflects the presence of powerful forelimbs associated with prey capture or dismemberment during feeding.” We also added a sentence in the ilium discussion, where we discuss the possible orientation of the hindlimb to acknowledge the limitations of the current data and the need for further evidence: “More remains of the hindlimb, especially of the femur, however, would be needed to test this hypothesis.” Figure 9:You mention this distolateral feature. Label it We have labeled the anterior distal fossa already. Thank you for considering our manuscript. We look forward to the opportunity to share our findings with the scientific community through PLOS ONE. Please do not hesitate to contact me if additional information is required. Sincerely, Diego Pol Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN) Buenos Aires, Argentina Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0328561.r002
3 Jul 2025 Decision Letter - Paolo Piras, Editor A new large hypercarnivorous crocodyliform from the Maastrichtian of Southern Patagonia, Argentina PONE-D-25-04716R1 Dear Dr. %Pol%, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Paolo Piras Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0328561.r003
Formally Accepted
Acceptance Letter - Paolo Piras, Editor PONE-D-25-04716R1 PLOS ONE Dear Dr. Pol, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Paolo Piras Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0328561.r004

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