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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

Trace evidence for melanin pigmentation in an Eocene fossil feather (USNM 584927).(a). The dark material towards the distal tip of the feather was examined under a scanning electron microscope. (b–d). Small clusters of elongate, rounded structures within the dark region are morphologically consistent with fossil melanosome casts5. Parameters for scanning electron micrographs: (b). 12 kv accelerating voltage, 5.5 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure; (c). 13 kv accelerating voltage, 5.3 spot size, 8.5 mm working distance, 1.4 torr water vapor pressure; (d). 13 kv accelerating voltage, 5.3 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure. Contrast and brightness have been altered for image clarity.
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f4: Trace evidence for melanin pigmentation in an Eocene fossil feather (USNM 584927).(a). The dark material towards the distal tip of the feather was examined under a scanning electron microscope. (b–d). Small clusters of elongate, rounded structures within the dark region are morphologically consistent with fossil melanosome casts5. Parameters for scanning electron micrographs: (b). 12 kv accelerating voltage, 5.5 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure; (c). 13 kv accelerating voltage, 5.3 spot size, 8.5 mm working distance, 1.4 torr water vapor pressure; (d). 13 kv accelerating voltage, 5.3 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure. Contrast and brightness have been altered for image clarity.

Mentions: A compression fossil feather from the Green River Formation was imaged with a scanning electron microscope (Fig. 4). The fossil feather had a fractured surface, and the fracture edges and valleys contained elongate structures with long axis lengths of 2–3 μm (Fig. 4). The elongate textures were visually-consistent with negative casts of melanosomes described elsewhere5.


Seeking carotenoid pigments in amber-preserved fossil feathers.

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

Trace evidence for melanin pigmentation in an Eocene fossil feather (USNM 584927).(a). The dark material towards the distal tip of the feather was examined under a scanning electron microscope. (b–d). Small clusters of elongate, rounded structures within the dark region are morphologically consistent with fossil melanosome casts5. Parameters for scanning electron micrographs: (b). 12 kv accelerating voltage, 5.5 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure; (c). 13 kv accelerating voltage, 5.3 spot size, 8.5 mm working distance, 1.4 torr water vapor pressure; (d). 13 kv accelerating voltage, 5.3 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure. Contrast and brightness have been altered for image clarity.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Trace evidence for melanin pigmentation in an Eocene fossil feather (USNM 584927).(a). The dark material towards the distal tip of the feather was examined under a scanning electron microscope. (b–d). Small clusters of elongate, rounded structures within the dark region are morphologically consistent with fossil melanosome casts5. Parameters for scanning electron micrographs: (b). 12 kv accelerating voltage, 5.5 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure; (c). 13 kv accelerating voltage, 5.3 spot size, 8.5 mm working distance, 1.4 torr water vapor pressure; (d). 13 kv accelerating voltage, 5.3 spot size, 8.4 mm working distance, 1.4 torr water vapor pressure. Contrast and brightness have been altered for image clarity.
Mentions: A compression fossil feather from the Green River Formation was imaged with a scanning electron microscope (Fig. 4). The fossil feather had a fractured surface, and the fracture edges and valleys contained elongate structures with long axis lengths of 2–3 μm (Fig. 4). The elongate textures were visually-consistent with negative casts of melanosomes described elsewhere5.

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