Phylogenetics Support Tyrannosaurus Rex's Evolutionary Relationship with Birds

Tyrannosaurus rex peptide sequences are more similar to modern-day birds than to reptiles, according to new research, providing added evidence for a relatively close evolutionary relationship between dinosaurs and birds.

About a year ago, researchers from Harvard University and elsewhere first reported that they could tease minuscule amounts of protein from mastodon and T. rex bone samples that were up to 600,000 and 68 million-years-old, respectively, and analyze them by mass spectrometry.

Now, members of the same team report using molecular phylogenetics to group mastodon and T. rex based on their collagen protein peptide sequences. These latest results, appearing in today’s issue of Science, suggest T. rex is more closely related to chickens and ostriches than to alligators and seem to confirm the long-held suspicion that dinosaurs and birds have a common ancestor. They also corroborate a relationship between mastodons and modern day elephants.

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