You claim that the identification of a 160,000-year-old Denisovan jawbone from its proteins alone is a first for palaeoproteomics (Nature 570, 433–436; 2019). This is not entirely true.
Jerold Lowenstein pioneered the detection and identification of proteins by immunological methods in fossils of hominins (a 0.5-million-year-old Homo erectus and a 1.9-million-year-old Australopithecus robustus) and other animal species (J. M. Lowenstein Phil. Trans. R. Soc. Lond. B 292, 143–149 (1981); see also C. Borja et al. Am. J. Phys. Anthropol. 103, 433–441; 1997).
Those immunological techniques relied on protein-binding information and so were less precise than mass spectrometry, which can directly provide the amino-acid sequence of fossil proteins such as collagen from the Denisovan mandible. Nevertheless, they were an important milestone in the history of molecular methods used to identify hominin fossils.
Nature 573, 196 (2019)