Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates

Rossi, Valentina; McNamara, Maria E.; Webb, S. M.; Itô, Shôsuke; Wakamatsu, Kazumasa

doi:10.1073/pnas.1820285116

Cited by 40 publications

(67 citation statements)

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“…A comparison of the chemical mapping of DLXH 1218 and other vertebrate fossils not only shows consistent patterns of chemical accumulation in the bones and feathers, but also indicates that elements behave differently depending on the chemical composition of the surrounding rocks, as previously reported. 8,31,41 Rossi and co-workers 14 concluded that the elemental signature of vertebrate fossils is tissue-specific and controlled by many biological and environmental factors, which is in agreement with our findings for DLXH 1218, namely, that the similarities and differences in the elemental distribution in the feathers and bones can be compared with finding for other vertebrate fossils. Since the composition of bones is representative of a particular depositional environment and most likely also the local condition where fossilization occurred, this variation of local compositional fingerprint could be used to assign poorly or not correct documented fossil to certain location.…”

Section: Comparisons With Chemistry Of Other Fossil Materialssupporting

confidence: 92%

“…1,[5][6][7][8][9][10][11][12] The chemistry of exquisitely preserved fossil animals, including several iconic flying/gliding theropods, have been investigated to reveal information on their paleobiology and the fossilization process. 1,6,9,10,[12][13][14] Various chemical imaging techniques, e.g. Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray spectroscopy, and secondary-ion mass spectroscopy (SIMS), have been employed to track the molecular, elemental and isotopic information.…”

Section: Introductionmentioning

confidence: 99%

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Micro-XRF Study Of The Troodontid Dinosaur Jianianhualong Tengi Reveals New Biological And Taphonomical Signals

Li¹,

Pei²,

Xu³

2020

At.Spectrosc.

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Jianianhualong tengi is a key taxon for understanding the evolution of pennaceous feathers as well as of troodontid theropods. It is known by only the holotype, which was recovered from the Lower Cretaceous Yixian Formation of western Liaoning, China. In this study, we carried out a large-area micro-X-Ray fluorescence (micro-XRF) analysis of the holotype of Jianianhualong tengi via a Brucker M6 Jetstream mobile XRF scanner. The elemental distribution measurements of the specimen show an enrichment of typical bone-associated elements, such as S, P and Ca, which allows to visualize the fossil structure. Additionally, the bones are enriched with several heavier elements, such as Sr, Th, Y and Ce relative to the surrounding rocks. The enrichment is most likely associated to secondary mineralization and the phosphates from the bones. Interestingly, the plumage shape correlates with an enrichment in elements, such as Cu, Ni and Ti, consistent with the findings of a previous study 1 on Archaeopteryx using synchrotron imaging. Elemental variations among the skeleton, the unguis and the sheath blade further indicate their possible compositional or ultrastructural differences, providing new biological and taphonomic information on the fossilized keratinous structures. An in-situ and nondestructive micro-XRF analysis is currently the most ideal way to map the chemistry of meter-sized fossils and has so far been mainly restricted to small samples. Micro-spatial chemical analysis of larger samples usually required a synchrotron facility. Our study demonstrated that a laboratory-based large-area micro-XRF scanner can provide a practical tool for the study of large specimens, thus allowing to collect full chemical data in order to obtain a better understanding of evolutionary and taphonomic processes.

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Section: Comparisons With Chemistry Of Other Fossil Materialssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Micro-XRF Study Of The Troodontid Dinosaur Jianianhualong Tengi Reveals New Biological And Taphonomical Signals

Li¹,

Pei²,

Xu³

2020

At.Spectrosc.

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“…Comparisons of chemical mappings of DLXH 1218 and other vertebrate fossils not only show consistent patterns of chemical accumulation in bones and feathers, but also indicate elements behave differently depending on the chemical composition of surrounding rocks, as previously noticed [8,30,37]. Rossi and co-workers [14] concluded that elemental signature of vertebrate fossils is tissue-specific and is controlled by many biological and environmental factors, which is congruent with our findings in DLXH 1218 that both similarities and differences could be recognized in the elemental distributions on feathers and bones compared with other vertebrate fossils. As the composition of the bones is representative for the depositional environment and most likely local condition of fossilization, this variation of local compositional fingerprint could be used to assign poorly or not correct documented fossil to certain location.…”

Section: Comparisons With Chemistry Of Other Fossil Materialssupporting

confidence: 63%

Micro-XRF study of the troodontid dinosaurJianianhualong tengireveals new biological and taphonomical signals

Pei

Teng³

et al. 2020

Preprint

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Jianianhualong tengi is a key taxon for understanding the evolution of pennaceous feathers as well as troodontid theropods, and it is known by only the holotype, which was recovered from the Lower Cretaceous Yixian Formation of western Liaoning, China. Here, we carried out a large-area micro-X-Ray fluorescence (micro-XRF) analysis on the holotypic specimen of Jianianhualong tengi via a Brucker M6 Jetstream mobile XRF scanner. The elemental distribution measurements of the specimen show an enrichment of typical bones couponing elements such as S, P and Ca allowing to visualize the fossil structure. Additionally, to this, the bones are enriched in several heavier elements such as Sr, Th, Y and Ce over the surrounding rocks. The enrichment is most likely associated to secondary mineralization and the phosphates from the bones. Interestingly the plumage shape correlates with an enrichment in elements such as Cu, Ni and Ti, consistent with a previous study [1] on Archaeopteryx using synchrotron imaging. The analysis presented here provide new biological and taphonomic information of this fossil. An in-situ and nondestructive micro-XRF analysis is currently the most ideal way to map the chemistry of fossils, so far this is manly restricted to small samples. Larger samples usually required a synchrotron facility for analysis. Our study demonstrated that laboratory-based large-area micro-XRF scanner can provides a practical tool for the study of large large-sized specimens allowing collect full chemical data for a better understanding of evolutionary and taphonomic processes.

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“…Integumentary coloration in fossils has been inferred from the visual tone of fossil tissues, melanosome geometry, distributions of melanin-associated metals and/or potential molecular fragments of melanin [3,4]. In the bird Confuciusornis [19], clusters of melanosomes of different morphologies (resembling eumelanosomes and pheomelanosomes of extant birds) and within-feather variations in Table S1 in the supplemental information online) [7,9,23,24,27,28,53,56,57,126,127]. Internal melanosomes are less common in extant birds and mammals than other vertebrate groups.…”

Section: Integumentary Coloration and Visual Signalingmentioning

confidence: 99%

Decoding the Evolution of Melanin in Vertebrates

McNamara

Rossi

Slater

et al. 2021

Trends in Ecology & Evolution

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Melanins are widespread pigments in vertebrates, with important roles in visual signaling, UV protection, and homeostasis. Fossil evidence of melanin and melanin-bearing organellesmelanosomesin ancient vertebrates may illuminate the evolution of melanin and its functions, but macroevolutionary trends are poorly resolved. Here, we integrate fossil data with current understanding of melanin function, biochemistry, and genetics. Mapping key genes onto phenotypic attributes of fossil vertebrates identifies potential genomic controls on melanin evolution. Taxonomic trends in the anatomical location, geometry, and chemistry of vertebrate melanosomes are linked to the evolution of endothermy. These shifts in melanin biology suggest fundamental links between melanization and vertebrate ecology. Tissue-specific and taxonomic trends in melanin chemistry support evidence for evolutionary tradeoffs between function and cytotoxicity. Melanin in Vertebrates Melanins (see Glossary) are dark to rufous pigments that are widespread in vertebrates and underpin critical functions in physiology and behavior [1]. Fossil evidence of melanin extending to over 300 million years ago has triggered a paradigm shift in paleobiology, prompting remarkable reconstructions of the coloration and behavior of extinct vertebrates [2-6]. New discoveries of internal melanins in vertebrate fossils have broadened our understanding of the functional diversity of ancient melanins [7-9] and invite a re-evaluation of the macroevolutionary history of melanin and its functions. Here, we synthesize trends in the fossil record of melanin and explore fossil evidence for the evolution of melanin function and the genetic basis of melanization. This highlights the value of the fossil record as a resource for tracking melanin evolution through deep time. Functions of Melanin in Ancient Vertebrates In extant vertebrates, melanin occurs as micron-sized organelles, melanosomes, in the integument, eyes and internal tissues and functions in photoprotection, visual signaling, thermoregulation, immunity, antioxidation, mechanical strengthening, and abrasion resistance [6,10,11] (Figure 1, Box 1). It is unclear which functions evolved first and which selection pressures dominate [11,12]. Fossils preserving evidence of melanin offer a unique temporal perspective. Melanin has been reported from fossil vertebrates from >25 localities from the Carboniferous to the Pliocene (Table S1 in the supplemental information online). The fossils include cyclostomes, fish, frogs, lizards, and other squamates, ichthyosaurs, plesiosaurs, turtles, pterosaurs, feathered and nonfeathered dinosaurs, birds, and mammals. This phylogenetically and temporally broad dataset yields evidence for ancient functions of melanin (Figure 2). Highlights In extant vertebrates melanin fulfils diverse roles including visual communication, photoprotection, antioxidation, and mechanical strengthening of tissues, but the evolution of these functions is debated. The discovery that melanosomes in fossil and modern ve...

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Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates

Cited by 40 publications

References 54 publications

Micro-XRF Study Of The Troodontid Dinosaur Jianianhualong Tengi Reveals New Biological And Taphonomical Signals

Micro-XRF Study Of The Troodontid Dinosaur Jianianhualong Tengi Reveals New Biological And Taphonomical Signals

Micro-XRF study of the troodontid dinosaurJianianhualong tengireveals new biological and taphonomical signals

Decoding the Evolution of Melanin in Vertebrates

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