Ancient enamel peptides recovered from the South American Pleistocene species Notiomastodon platensis and Myocastor cf. coypus.

We used two fossil teeth from South American Pleistocene mammals to obtain subsuperficial acid etching samples. We employed samples from the species Notiomastodon platensis and Myocastor cf. coypus for the enamel etchings. The controls included an extant rodent (rat). After the first etching was discarded, a second 20-s etching (i.e. , subsuperficial) was directly collected with a ZipTip and injected into an LTQ Orbitrap Velos for MS analysis. The peptides were identified with different software programs that used Peptide Spectrum Match (PSM) and de novo sequencing including similarity search strategies. Most of the peptides that were recovered from the enamel of the fossils belonged to enamel-specific proteins. To our knowledge, this is the first study that has described the recovery of enamel peptide molecules from extinct South American taxa, indicating that enamel peptide data from late Pleistocene fossils can be employed as an additional parameter for phylogenetic analysis, and that the sample can be obtained by a very conservative acid etching, with almost no damage to the fossils. This study shows that it is possible to obtain information based on plenty of ancient peptides recovered from subsuperficial enamel of fossil teeth from South American Pleistocene. The quality of the data suggests that peptides are likely the best preserved biomolecules under certain harsh environmental conditions. The recovery procedure only lasted 20 s and was minimally destructive to the fossils. This opens a myriad of new possibilities for the study of the past. [Display omitted] • Enamel-specific peptides were recovered from South American Pleistocene mammals • Recovery was extremely simple, lasted only 20 s, and consisted of diluted acid etching followed by direct peptide collection from the enamel surface • This procedure allowed dozens of peptides to be recovered from enamel proteins, with minimal contamination by unexpected peptides • This procedure will enable access to ancient biomolecules that have been stored in enamel for thousands to millions of years with minimal damage to fossils [ABSTRACT FROM AUTHOR]