: The centerpiece of Chatterjee's work is Protoavis texensis , a fossil found in Texas in 1983. He argues this creature pushes the origin of birds back to the Late Triassic, approximately 225 million years ago—predating the famous Archaeopteryx by 75 million years.
: Chatterjee advocates for the "trees-down" (arboreal) theory , suggesting that flight evolved from gliding between trees rather than running on the ground ("ground-up"). Evolutionary Timeline The Rise of Birds: 225 Million Years of Evolution
: Flight refinement and global diversification during continental breakup, including detailed analysis of feathered dinosaur finds in China. : The centerpiece of Chatterjee's work is Protoavis
: A sudden decline and near-extinction of most bird lineages alongside dinosaurs roughly 65 million years ago. The Rise of Birds: 225 Million Years of Evolution