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Seeking carotenoid pigments in amber-preserved fossil feathers.

Thomas DB, Nascimbene PC, Dove CJ, Grimaldi DA, James HF - Sci Rep (2014)

Bottom Line: Plumage colours bestowed by carotenoid pigments can be important for visual communication and likely have a long evolutionary history within Aves.With reference to a modern feather, we sought chemical evidence of carotenoids in six feathers preserved in amber (Miocene to mid-Cretaceous) and in a feather preserved as a compression fossil (Eocene).Significantly, we show that carotenoid plumage pigments can be detected without sample destruction through an amber matrix using confocal Raman spectroscopy.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA [2].

ABSTRACT
Plumage colours bestowed by carotenoid pigments can be important for visual communication and likely have a long evolutionary history within Aves. Discovering plumage carotenoids in fossil feathers could provide insight into the ecology of ancient birds and non-avian dinosaurs. With reference to a modern feather, we sought chemical evidence of carotenoids in six feathers preserved in amber (Miocene to mid-Cretaceous) and in a feather preserved as a compression fossil (Eocene). Evidence of melanin pigmentation and microstructure preservation was evaluated with scanning electron and light microscopies. We observed fine microstructural details including evidence for melanin pigmentation in the amber and compression fossils, but Raman spectral bands did not confirm the presence of carotenoids in them. Carotenoids may have been originally absent from these feathers or the pigments may have degraded during burial; the preservation of microstructure may suggest the former. Significantly, we show that carotenoid plumage pigments can be detected without sample destruction through an amber matrix using confocal Raman spectroscopy.

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Related in: MedlinePlus

Raman spectra from a fossil feather preserved in amber and from a carbonised compression fossil.Amber matrix, epoxy resin and fossil feather each had a distinct spectral signature. Near-identical spectra were collected from the fossil feathers and from the Green River Formation sediment. Yellow bars indicate locations where peaks are expected in spectra from carotenoids (see Fig. 1), showing that evidence for carotenoid pigmentation was not recovered from AMNH DR-14-32 (feather in amber) or USNM 584927 (compression fossil). Spectra have been baseline-corrected and smoothed. Spectral intensities have been normalized against the minimum and maximum values. Epoxy was only around the outside of the amber matrix, as oriented in the image, and not above and below the amber.
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f2: Raman spectra from a fossil feather preserved in amber and from a carbonised compression fossil.Amber matrix, epoxy resin and fossil feather each had a distinct spectral signature. Near-identical spectra were collected from the fossil feathers and from the Green River Formation sediment. Yellow bars indicate locations where peaks are expected in spectra from carotenoids (see Fig. 1), showing that evidence for carotenoid pigmentation was not recovered from AMNH DR-14-32 (feather in amber) or USNM 584927 (compression fossil). Spectra have been baseline-corrected and smoothed. Spectral intensities have been normalized against the minimum and maximum values. Epoxy was only around the outside of the amber matrix, as oriented in the image, and not above and below the amber.

Mentions: Five fossil feathers preserved in amber had been embedded in an epoxy resin. The epoxy resin had a distinct Raman spectrum with bands at 1110, 1181, 1220, 1289, 1450 and 1610 cm−1 (Fig. 2). Raman spectra from the amber matrices had bands at 1193, 1436, 1452 and 1647 cm−1. Note that carotenoid-identifying Raman bands were not observed in spectra collected from amber matrices (electronic supplementary information). All spectra from all analyses of the feathers in amber contained the 1078 cm−1 band, and many spectra contained amber spectral bands (Fig. 2). The 1078 cm−1 band was also the only feature in spectra from the Green River Formation fossil feather, and in spectra from the Green River Formation sedimentary matrix. Raman spectral evidence for carotenoid pigmentation was not recovered from the fossil feathers.


Seeking carotenoid pigments in amber-preserved fossil feathers.

Thomas DB, Nascimbene PC, Dove CJ, Grimaldi DA, James HF - Sci Rep (2014)

Raman spectra from a fossil feather preserved in amber and from a carbonised compression fossil.Amber matrix, epoxy resin and fossil feather each had a distinct spectral signature. Near-identical spectra were collected from the fossil feathers and from the Green River Formation sediment. Yellow bars indicate locations where peaks are expected in spectra from carotenoids (see Fig. 1), showing that evidence for carotenoid pigmentation was not recovered from AMNH DR-14-32 (feather in amber) or USNM 584927 (compression fossil). Spectra have been baseline-corrected and smoothed. Spectral intensities have been normalized against the minimum and maximum values. Epoxy was only around the outside of the amber matrix, as oriented in the image, and not above and below the amber.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048910&req=5

f2: Raman spectra from a fossil feather preserved in amber and from a carbonised compression fossil.Amber matrix, epoxy resin and fossil feather each had a distinct spectral signature. Near-identical spectra were collected from the fossil feathers and from the Green River Formation sediment. Yellow bars indicate locations where peaks are expected in spectra from carotenoids (see Fig. 1), showing that evidence for carotenoid pigmentation was not recovered from AMNH DR-14-32 (feather in amber) or USNM 584927 (compression fossil). Spectra have been baseline-corrected and smoothed. Spectral intensities have been normalized against the minimum and maximum values. Epoxy was only around the outside of the amber matrix, as oriented in the image, and not above and below the amber.
Mentions: Five fossil feathers preserved in amber had been embedded in an epoxy resin. The epoxy resin had a distinct Raman spectrum with bands at 1110, 1181, 1220, 1289, 1450 and 1610 cm−1 (Fig. 2). Raman spectra from the amber matrices had bands at 1193, 1436, 1452 and 1647 cm−1. Note that carotenoid-identifying Raman bands were not observed in spectra collected from amber matrices (electronic supplementary information). All spectra from all analyses of the feathers in amber contained the 1078 cm−1 band, and many spectra contained amber spectral bands (Fig. 2). The 1078 cm−1 band was also the only feature in spectra from the Green River Formation fossil feather, and in spectra from the Green River Formation sedimentary matrix. Raman spectral evidence for carotenoid pigmentation was not recovered from the fossil feathers.

Bottom Line: Plumage colours bestowed by carotenoid pigments can be important for visual communication and likely have a long evolutionary history within Aves.With reference to a modern feather, we sought chemical evidence of carotenoids in six feathers preserved in amber (Miocene to mid-Cretaceous) and in a feather preserved as a compression fossil (Eocene).Significantly, we show that carotenoid plumage pigments can be detected without sample destruction through an amber matrix using confocal Raman spectroscopy.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA [2].

ABSTRACT
Plumage colours bestowed by carotenoid pigments can be important for visual communication and likely have a long evolutionary history within Aves. Discovering plumage carotenoids in fossil feathers could provide insight into the ecology of ancient birds and non-avian dinosaurs. With reference to a modern feather, we sought chemical evidence of carotenoids in six feathers preserved in amber (Miocene to mid-Cretaceous) and in a feather preserved as a compression fossil (Eocene). Evidence of melanin pigmentation and microstructure preservation was evaluated with scanning electron and light microscopies. We observed fine microstructural details including evidence for melanin pigmentation in the amber and compression fossils, but Raman spectral bands did not confirm the presence of carotenoids in them. Carotenoids may have been originally absent from these feathers or the pigments may have degraded during burial; the preservation of microstructure may suggest the former. Significantly, we show that carotenoid plumage pigments can be detected without sample destruction through an amber matrix using confocal Raman spectroscopy.

Show MeSH
Related in: MedlinePlus