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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

Carotenoid feather pigments can be detected through an amber matrix with Raman spectroscopy.Band assignment symbols: a – amber; c – carotenoid; k – keratin; m – ‘melanin'; * – spectral noise. Although the spectrum from the melanin-pigmented black feather barbs contained a single spectral band (m), this band is not unequivocal evidence for the presence of melanin (see Fig. 2). Spectra have been baseline-corrected and smoothed; feather from a European greenfinch Carduelis chloris.
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f1: Carotenoid feather pigments can be detected through an amber matrix with Raman spectroscopy.Band assignment symbols: a – amber; c – carotenoid; k – keratin; m – ‘melanin'; * – spectral noise. Although the spectrum from the melanin-pigmented black feather barbs contained a single spectral band (m), this band is not unequivocal evidence for the presence of melanin (see Fig. 2). Spectra have been baseline-corrected and smoothed; feather from a European greenfinch Carduelis chloris.

Mentions: Raman spectra from the yellow barbs of a European greenfinch (Carduelis chloris i.e. modern bird) feather had distinctive carotenoid-informative bands at 1530 and 1153 cm−1681011 (Fig. 1). A third prominent band at 1001 cm−1 identified both the carotenoid pigment and the feather keratin. Bands at 1444 cm−1 and 1657 cm−1 also identified keratin. The spectrum from the black barbs of the same European greenfinch feather had a single band at 1078 cm−1 as the only discernible feature; assignments for the 1078 cm−1 band have not been found in published sources. The 1078 cm−1 band was evident alongside the 1530 cm−1, 1153 cm−1 and 1001 cm−1 bands in the yellow-black barb from the European greenfinch feather. The 1078 cm−1 band was not observed in spectra collected from the yellow feather barbs or the three instrument standards (acetaminophen, calcite, cyclohexane). Spectra from the black and yellow-black feather barbs were collected at low laser powers and consequently had high levels of spectral noise, which manifested as spectral artifacts after baseline correction and spectral smoothing (Fig. 1).


Seeking carotenoid pigments in amber-preserved fossil feathers.

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

Carotenoid feather pigments can be detected through an amber matrix with Raman spectroscopy.Band assignment symbols: a – amber; c – carotenoid; k – keratin; m – ‘melanin'; * – spectral noise. Although the spectrum from the melanin-pigmented black feather barbs contained a single spectral band (m), this band is not unequivocal evidence for the presence of melanin (see Fig. 2). Spectra have been baseline-corrected and smoothed; feather from a European greenfinch Carduelis chloris.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Carotenoid feather pigments can be detected through an amber matrix with Raman spectroscopy.Band assignment symbols: a – amber; c – carotenoid; k – keratin; m – ‘melanin'; * – spectral noise. Although the spectrum from the melanin-pigmented black feather barbs contained a single spectral band (m), this band is not unequivocal evidence for the presence of melanin (see Fig. 2). Spectra have been baseline-corrected and smoothed; feather from a European greenfinch Carduelis chloris.
Mentions: Raman spectra from the yellow barbs of a European greenfinch (Carduelis chloris i.e. modern bird) feather had distinctive carotenoid-informative bands at 1530 and 1153 cm−1681011 (Fig. 1). A third prominent band at 1001 cm−1 identified both the carotenoid pigment and the feather keratin. Bands at 1444 cm−1 and 1657 cm−1 also identified keratin. The spectrum from the black barbs of the same European greenfinch feather had a single band at 1078 cm−1 as the only discernible feature; assignments for the 1078 cm−1 band have not been found in published sources. The 1078 cm−1 band was evident alongside the 1530 cm−1, 1153 cm−1 and 1001 cm−1 bands in the yellow-black barb from the European greenfinch feather. The 1078 cm−1 band was not observed in spectra collected from the yellow feather barbs or the three instrument standards (acetaminophen, calcite, cyclohexane). Spectra from the black and yellow-black feather barbs were collected at low laser powers and consequently had high levels of spectral noise, which manifested as spectral artifacts after baseline correction and spectral smoothing (Fig. 1).

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