More Original Protein Found in Older Bird Fossil
The new discovery from China dates back 130 million years on the evolutionary timeline.
A few days ago, we reported the discovery of melanin from a fossil bird found in the Liaoning Province, China, that was dated at 120 million years (early Cretaceous) in the evolutionary scheme. Now, another discovery from the Jehol strata of China is said to be 10 million years older: 130 million years.
The discovery by Pan et al., “Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis,” is published in the Proceedings of the National Academy of Sciences. Once again, Mary Schweitzer from North Carolina State is listed as a co-author. A laymen’s writeup is on Science Daily, taken from an NC State press release. Schweitzer has been in the thick of reports about soft tissue in dinosaur bones and other dinosaur-era fossils.
New research from North Carolina State University, the Chinese Academy of Sciences and Linyi University has found evidence of original keratin and melanosome preservation in a 130-million-year-old Eoconfuciusornis specimen. The work extends the timeframe in which original molecules may preserve, and demonstrates the ability to distinguish between ancient microstructures in fossils.
Eoconfuciusornis, crow-sized primitive birds that lived in what is now China around 130 million years ago, are the earliest birds to have a keratinous beak and no teeth, like modern birds. Previous studies argued that the feathers of these and other ancient birds and dinosaurs preserved small, round structures interpreted to be melanosomes – pigment-containing organelles that, along with other pigments, give feathers their color.
Electron micrographs and gold-tipped antibodies that bind to melanin were used to make the identification. Another technique clinched the identity of original protein:
Finally, they mapped copper and sulfur to these feathers at high resolution. Sulfur was broadly distributed, reflecting its presence in both keratin and melanin molecules in modern feathers. However copper, which is only found in modern melanosomes, and not part of keratin, was only observed in the fossil melanosomes. These findings both support the identity of the melanosomes and indicate that there was no mixing or leaching during decomposition and fossilization.
The paper describes how they avoided contamination. The antibody tests confirm that the proteinaceous is original. In modern feathers, melanosomes are “always surrounded by and embedded in keratin.” The scientists demonstrate this was true in the fossil as well.
Our work represents the oldest ultrastructural and immunological recognition of avian beta-keratin from an Early Cretaceous (∼130-Ma) bird. We apply immunogold to identify protein epitopes at high resolution, by localizing antibody–antigen complexes to specific fossil ultrastructures. Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils.
Confuciusornis was clearly a strong flyer. Artist renditions of Eoconfuciusornis (“dawn Confuciusornis“) show it also equipped for flying.
So how did “normally labile tissues” last for 130 million years? The researches speculate about needle-like crystals of calcium they found on the fossil:
These Ca-concentrated needle-shaped structures are absent in extant feathers. Thus, we hypothesize that precipitation of calcium, possibly mediated by microbes during the fossilization process, facilitated ultrastructural and molecular preservation of the feathers by stabilizing them at the molecular level before they could completely degrade. It has long been known that the association with mineral substrates greatly enhances the preservation potential of biomolecules. Furthermore, it has been proposed that calcium may incorporate into molecular fragments, conferring stability, and that this process may be microbially mediated. Because the surrounding sediments of this Eoconfuciusornis specimen consist mainly of Al silicates, with little or no calcium detected, the source of the calcium observed in these feathers remains unknown.
So while the presence of calcium crystals could “possibly” stabilize the proteins (for support, the team references a 1999 paper by Schweitzer), they don’t know where it came from. They propose another stabilizing influence:
Another factor that may contribute to the unique biomaterial properties of feathers is the epidermal differentiation cysteine-rich protein. This molecule has the same gene structure as beta-keratins, and is coexpressed with them at certain stages of development in most keratinized tissues of living birds. However, it is only in feathers that this protein continues to be detected throughout life. The greatly elevated cysteine levels in this protein facilitate intramolecular cross-linking, and contribute to the stability and resistance of feathers to degradation. Further molecular recovery of ancient feather materials may allow direct testing of these hypotheses.
It should be possible to measure degradation rates of feather keratin and melanosomes due to the presence of calcium or cysteine. But if either of these processes are so efficient, it would seem original feather material should be common in bird fossils, and we should find preserved fossils over a wide range, from recent kills all the way back. 130 million years is a long, long time to have to account for the preservation of original protein material.
Creationists are winning this case. Why? (1) Evolutionists did not predict this, and (2) they are scrambling to explain it away. You just heard them call these proteins “normally labile tissues.” Labile means easily altered, broken down or degraded. But the team hollered, It tastes like chicken!
Indeed, if both microbodies and matrix are preserved, tests can be conducted to chemically characterize the composition of each. If these bodies are melanosomes, they should be contained within a keratinous matrix; if they are microbial in origin, this matrix should consist of exopolymeric substances secreted by the microbes and subsequently mineralized. To distinguish between these alternative hypotheses, we applied multiple methods, well-established for molecular and chemical characterization of modern materials, to chicken (Gallus gallus) feathers and to preserved feathers of a new specimen of the bird Eoconfuciusornis [Shandong Tianyu Museum of Nature (STM) 7-144] (Pygostylia: Confuciusornithiformes) (Fig. 1A) from the 130-Ma Protopteryx horizon of the Huajiying Formation in Fengning, northern Hebei, China. Our results are consistent with the retention of original organic components derived from both keratin and melanin, thus supporting a melanosome origin for these ancient microstructures.