Study Suggests Early Cretaceous Bird Had Flashy Feathers

Fossils from the Jiufotang Formation of Liaoning Province (China), have provided scientists with an extensive data set that records life in the Early Cretaceous.  The highly fossiliferous strata (referred to as a Lagerstätte), has given palaeontologists a deep understanding of the fauna of a forested habitat with many large lakes.  Numerous fossils of turtles, pterosaurs, fish, mammals and dinosaurs have been described, but perhaps the Jehol Biota’s greatest contribution to our understanding of vertebrate evolution has come from the large numbers of bird fossils that have been found.  A team of international researchers have studied the ancient feathers of one such bird and deduced that it had sparkly, iridescent feathers probably for display in a bid to attract a mate.

Ancient Prehistoric Bird Provides Evidence of Iridescent Feathers

Ventral view and line drawing of the bohaiornithid bird specimen.

Ventral view of the new bohaiornithid specimen (CUGB P1202, primary slab). A, photograph of the primary slab. B, interpretive drawing.

Picture Credit: Jennifer A. Peteya (University of Akron)

A Bohaiornithid Bird with Bling

Scientists from Akron University (Ohio), the University of Texas at Austin in association with Chinese colleagues have studied the slab and counter slab of a beautifully preserved primitive bird.  Using high magnification and a non-destructive chemical technique to identify molecule signatures (Ramon spectroscopy), the team have identified melanosome structures that are associated with iridescent colouration in modern birds.

The image above shows a view of the primary slab showing the bird fossil (A), whereas (B) shows an interpretative line drawing of this enantiornithine.  The bird has been classified as a basal member of the Enantiornithes clade and the teeth in the tiny beak have led to the fossil being assigned to the Bohaiornithidae family (predatory birds).  As far as we at Everything Dinosaur are aware, no genus name has been assigned as yet.

The Rich and Diverse Early Cretaceous Forests of Northern China

The rich and diverse Daohugou Biota.

A rich and diverse environment dominated by small mammals, Pterosaurs, primitive birds and feathered Theropods.

Picture Credit: Julia Molnar

What are Melanosomes?

Using electron microscopes to look inside the feathers of the ancient bird, the research team were able to identify strange shapes and structures.  These are melanosomes, which when the animal was alive would have contained the pigment melanin.  This light-absorbing pigment is what gives colour to human hair and animal fur, as well as to the feathers of dinosaurs and birds.  The shape of the melanosome suggests the colour.  The crown, neck, and body contour feathers retain elongate melanosome structures associated with weakly iridescent colouration in living birds, so the team have concluded that this prehistoric bird was also iridescent.

Identifying Melanosomes in a Fossil Bird

Evidence of preserved melanosomes in Early Cretaceous bird.

The right wing and body contour feathers of the primitive bird (specimen CUGB P1202). Photographs B and C are highly magnified sections showing preserved melanosomes.

Picture Credit: Jennifer A. Peteya (University of Akron)

The photograph above shows part of the fossil from the primary slab (specimen number CUGB P1202).  Part (A) shows a close up of the right wing and the long contour feathers next to the tibia (lower leg bone).  The white triangle and white circle show the location of melanosome sampling sites.  Long, linear structures can be seen under high magnification in (B), the scientists have concluded that these are melanosomes, Photograph B is a highly magnified section or contour feathers near the tibia – the white triangle sampling spot.  Photograph (C) shows potential degraded melanosomes from the right wing sampling site – the white circle.  Scale bars represent 1 cm (A); 1 μm (B, C).

A Showy Sub-Adult Specimen

Colourful displays are commonplace in extant birds and many species use bright feathers for courtship display.  This specimen provides evidence of potential intraspecific communication using plumage in a member of the Bohaiornithidae.  Unfused bones in the skeleton indicate that this individual was a sub-adult, it seems these primitive birds did not hang about when it came to finding a mate.

Commenting on the significance of the study, lead researcher Dr Jennifer Peteya (University of Akron) stated:

“Many enantiornithine birds possessed ornate feathers.  This new specimen shows that some enantiornithines also had iridescent feathers and unlike most modern birds, these flashy ornaments developed before the animal was fully grown.”

The scientific paper: “The Plumage and Colouration of an Enantiornithine Bird from the Early Cretaceous of China”, published in the journal “Palaeontology”.

To read an article on the discovery of melanosome structures in a Chinese dinosaur fossil: Sinosauropteryx – A Ginger Dinosaur!

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