12/3/2023 0 Comments Feathered dinosaurs muse magazine![]() ![]() Since the late 1990s, a steady stream of discoveries has changed our image of dinosaurs from slow and reptile-like to agile and, most surprisingly, feathery creatures. In extant birds, iridescent feathers play a role in sexual selection and display (think of the magnificent birds of paradise), and this may have been the case in early birds as well.įrom enanthiornithines we hop down the evolutionary tree to a different yet equally feathered branch, that of the non-avian theropods, a group of theropods that is closely related to, yet not ancestral to living birds. Unfortunately, it is impossible to determine the specific hue of the iridescent feathers in this specimen, since the nanostructures through which the light scatters, such as layers of β-keratin, are not preserved. Althought this is not the first finding of iridescent fossil feathers (for instance, see Vinther et al., 2010 and Li et al., 2012), it is the oldest evidence of iridescent feathers in enanthiornithines. In addition, the elongated shape and the slight parallel organisation of the melanosomes in the fossil samples is also seen in iridescent feathers of living birds.īoth the Raman spectra and the organization of the melanosomes in the fossil specimen suggest that this extinct bird had iridescent feathers. Peteya and colleagues found that Raman spectra of samples of the fossil specimen show two peaks, similar to spectra of eumelanin, a melanin pigment found in black, brown and iridescent feathers. The vibrational spectrum of the light scattered off the sample allows you to identify the different molecules in the sample. Curious to see if the fossil melanosomes still contained melanin, Peteya and colleagues used Raman spectroscopy, a technique in which a sample is illuminated by a laser beam. Melanin is visible in feathers (and the skin) of living birds as small granules, and produces a range of colours from black to brown and yellow. ![]() Melanosomes are organelles in the cells of animals that produce melanin, one of the three main categories of pigments in bird feathers. These granules are similar in size, shape and chemistry to melanosomes in living birds, which led Peteya and her colleagues to believe that the granules in the fossil specimen must be melanosomes as well. Upon closer look, Jennifer Peteya and her colleagues noticed that the feathers contain three-dimensionally preserved elongated granules. Inset: elongate three-dimensional melanosomes are visible in feathers from the crown. The skull of the new bohaiornithid with feathers clearly visible around the head and neck. But what’s most remarkable about this specimen is that the feathers contain traces of their original colours, which means that we can reconstruct the coloration of this extinct lineage of early birds. The specimen displays exceptional feather preservation: the head is surrounded by a halo of dark feathers, the flight feathers are clearly visible along the side of the body, and two elongated (and probably ornamental) feathers emerge from the tail. The latest discovery from the Jehol concerns a new (yet unnamed) species of the basal enanthiornitine family Bohaiornithidae (Peteya et al., 2016). ![]() These finds have contributed greatly to our understanding of the dinosaur-bird transition and the rise of early birds, and new discoveries continue to today. Over the years, we have seen a highly diverse assemblage of avian and non-avian dinosaurs with skeletons preserved fully articulated, with visible soft tissue traces and stomach contents, and most stunningly, evidence for feathers in both avian and non-avian dinosaurs. Early Cretaceous (approximately 131-120 million years ago) in age, the Jehol biota covers a period with a high diversity of fossils, including plants, invertebrates, dinosaurs and mammals, but it is best known for its exquisitely preserved feathered dinosaurs. The Jehol Biota from Northeastern China has proven to be a fossil treasure trove. ![]()
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