Organic molecules extracted from a 48-million-year-old fossilized bird are the remains of lipids produced by a gland involved in feather maintenance.
Previous studies have suggested that structures found in fossilized birds from Germany’s Messel Pit fossil site are preserved uropygial glands, which secrete oil for preening the feathers.
Shane O’Reilly at the Massachusetts Institute of Technology in Cambridge and his colleagues analysed one bird fossil using mass spectroscopy, and identified a range of alkenes, alkanes and complex lipid molecules in the purported gland. Comparisons with uropygial secretions from modern birds suggest that the preserved molecules are the chemically altered remains of wax esters used to maintain feathers. This shows that even lipid-rich soft tissues can be preserved over geological time scales, the authors say.