An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics

Predator-prey dynamics are an important evolutionary driver of escalating predation mode and efficiency, and commensurate responses of prey. Among these strategies, camouflage is important for visual concealment, with countershading the most universally observed. Extant terrestrial herbivores free o...

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Main Authors: Brown, Caleb M., Henderson, Donald M., Vinther, Jakob, Fletcher, Ian, Sistiaga Guiterrez, Maria Ainara, Herrera Bethencourt, Jorsua, Summons, Roger E
Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Format: Article
Published: Elsevier BV 2018
Online Access:http://hdl.handle.net/1721.1/118950
https://orcid.org/0000-0002-7144-8537
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author Brown, Caleb M.
Henderson, Donald M.
Vinther, Jakob
Fletcher, Ian
Sistiaga Guiterrez, Maria Ainara
Herrera Bethencourt, Jorsua
Summons, Roger E
author2 Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
author_facet Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Brown, Caleb M.
Henderson, Donald M.
Vinther, Jakob
Fletcher, Ian
Sistiaga Guiterrez, Maria Ainara
Herrera Bethencourt, Jorsua
Summons, Roger E
author_sort Brown, Caleb M.
collection MIT
description Predator-prey dynamics are an important evolutionary driver of escalating predation mode and efficiency, and commensurate responses of prey. Among these strategies, camouflage is important for visual concealment, with countershading the most universally observed. Extant terrestrial herbivores free of significant predation pressure, due to large size or isolation, do not exhibit countershading. Modern predator-prey dynamics may not be directly applicable to those of the Mesozoic due to the dominance of very large, visually oriented theropod dinosaurs. Despite thyreophoran dinosaurs’ possessing extensive dermal armor, some of the most extreme examples of anti-predator structures, little direct evidence of predation on these and other dinosaur megaherbivores has been documented. Here we describe a new, exquisitely three-dimensionally preserved nodosaurid ankylosaur, Borealopelta markmitchelli gen. et sp. nov., from the Early Cretaceous of Alberta, which preserves integumentary structures as organic layers, including continuous fields of epidermal scales and intact horn sheaths capping the body armor. We identify melanin in the organic residues through mass spectroscopic analyses and observe lighter pigmentation of the large parascapular spines, consistent with display, and a pattern of countershading across the body. With an estimated body mass exceeding 1,300 kg, B. markmitchelli was much larger than modern terrestrial mammals that either are countershaded or experience significant predation pressure as adults. Presence of countershading suggests predation pressure strong enough to select for concealment in this megaherbivore despite possession of massive dorsal and lateral armor, illustrating a significant dichotomy between Mesozoic predator-prey dynamics and those of modern terrestrial systems.
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spelling mit-1721.1/1189502022-10-03T11:13:11Z An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics Brown, Caleb M. Henderson, Donald M. Vinther, Jakob Fletcher, Ian Sistiaga Guiterrez, Maria Ainara Herrera Bethencourt, Jorsua Summons, Roger E Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Sistiaga Guiterrez, Maria Ainara Herrera Bethencourt, Jorsua Summons, Roger E Predator-prey dynamics are an important evolutionary driver of escalating predation mode and efficiency, and commensurate responses of prey. Among these strategies, camouflage is important for visual concealment, with countershading the most universally observed. Extant terrestrial herbivores free of significant predation pressure, due to large size or isolation, do not exhibit countershading. Modern predator-prey dynamics may not be directly applicable to those of the Mesozoic due to the dominance of very large, visually oriented theropod dinosaurs. Despite thyreophoran dinosaurs’ possessing extensive dermal armor, some of the most extreme examples of anti-predator structures, little direct evidence of predation on these and other dinosaur megaherbivores has been documented. Here we describe a new, exquisitely three-dimensionally preserved nodosaurid ankylosaur, Borealopelta markmitchelli gen. et sp. nov., from the Early Cretaceous of Alberta, which preserves integumentary structures as organic layers, including continuous fields of epidermal scales and intact horn sheaths capping the body armor. We identify melanin in the organic residues through mass spectroscopic analyses and observe lighter pigmentation of the large parascapular spines, consistent with display, and a pattern of countershading across the body. With an estimated body mass exceeding 1,300 kg, B. markmitchelli was much larger than modern terrestrial mammals that either are countershaded or experience significant predation pressure as adults. Presence of countershading suggests predation pressure strong enough to select for concealment in this megaherbivore despite possession of massive dorsal and lateral armor, illustrating a significant dichotomy between Mesozoic predator-prey dynamics and those of modern terrestrial systems. Suncor Energy Royal Tyrrell Museum Cooperating Society National Geographic Society (U.S.) 2018-11-08T15:04:51Z 2018-11-08T15:04:51Z 2017-08 2017-05 2018-10-02T18:06:45Z Article http://purl.org/eprint/type/JournalArticle 0960-9822 http://hdl.handle.net/1721.1/118950 Brown, Caleb M., et al. “An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics.” Current Biology, vol. 27, no. 16, Aug. 2017, pp. 2514-2521.e3. © 2017 The Authors https://orcid.org/0000-0002-7144-8537 http://dx.doi.org/10.1016/J.CUB.2017.06.071 Current Biology Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf Elsevier BV Elsevier
spellingShingle Brown, Caleb M.
Henderson, Donald M.
Vinther, Jakob
Fletcher, Ian
Sistiaga Guiterrez, Maria Ainara
Herrera Bethencourt, Jorsua
Summons, Roger E
An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics
title An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics
title_full An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics
title_fullStr An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics
title_full_unstemmed An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics
title_short An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics
title_sort exceptionally preserved three dimensional armored dinosaur reveals insights into coloration and cretaceous predator prey dynamics
url http://hdl.handle.net/1721.1/118950
https://orcid.org/0000-0002-7144-8537
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