Response to Comment on "Protein Sequences from Mastodon and Tyrannosaurus rex Revealed by Mass Spectrometry"

We sequenced six endogenous collagen peptides from Tyrannosaurus rex bone fragments using mass spectrometry. Five sequences match birds, but only two match amphibians, supporting dinosaur-bird relationships. Buckley et al. reinterpret and misinterpret our data and question sequence authenticity, but they used a suboptimal phylogenetic algorithm to analyze only a subset of reported sequences and they suggest analyses that are less sensitive and less specific than mass spectrometry. We disagree and use data to explain.