The first dinosaur egg was soft

Pushing Raman spectroscopy over the edge: purported signatures of organic molecules in fossils are instrumental artefacts

“…The transmission properties of the edge filter induce ripples on the measured spectra when luminescence is intense, making it challenging to identify Raman features without appropriate data processing for background subtraction [33] . The data provided in the publications questioned here [15][16][17][18][19][20] are only the baseline-subtracted spectra, not the raw data, which makes it impossible to precisely assess the impact of non-Raman processes and sample composition on the corrected spectra from which the presence of organic molecules was inferred. To address these issues, we collected Raman microspectroscopy data on modern and fossil crustaceans in analytical conditions similar to those of the aforementioned studies (for details, see Material and Methods in SI).…”

“…Recently, preservation of diverse organic degradation products of biomolecules in more than a hundred different metazoan fossils was inferred from spectroscopy data collected with a Raman microspectrometer using a 532 nm laser as the excitation source under continuous illumination [15][16][17][18][19][20] . The reported spectroscopic data were interpreted as evidence for the preservation of organic pigments in eumaniraptoran dinosaur eggshells [15] and in a non-avian dinosaur skin [18] , as well as of protein, lipid and/or sugar fossilization products in fossil bones [16] , dinosaur eggshells [20] , and vertebrate and invertebrate soft-tissues [17,19] .…”

Hard evidence from soft fossil eggs

“…By contrast, soft-shelled eggs, such as those of most lizards and snakes, have leathery outer coverings that decay rapidly and thus are only rarely preserved. Now, Norell et al 1 (page 406) and Legendre et al 2 (page 411) describe multimillion-year-old softshelled eggs that might alter the prevailing view of dinosaur reproduction, and possibly also change current thinking about ancient marine reptiles.…”

“…A few dinosaur groups, including sauropods, laid hard-shelled eggs. Norell et al 1 report the discovery that two types of dinosaur laid soft-shelled eggs. The authors analysed Mussaurus eggs that are between 227 million and 209 million years old, and Protoceratops eggs of between 84 million and 72 million years old.…”

“…It is estimated that SARS-CoV-2 has already infected more than 9 million people and claimed more than 450,000 lives worldwide, and this pandemic has paralysed economies globally. On page 437, Zhang et al 1 present data on the evolution of two major lineages of SARS-CoV-2, together with information regarding human-host determinants of disease severity from their analysis of 326 people in Shanghai, China, who were infected with SARS-CoV-2. SARS-CoV-2, which caught the world by surprise, was initially thought to have 'jumped' to humans from an animal host at the Huanan Seafood Wholesale Market in Wuhan, China.…”