- An international team of scientists has created the largest and most detailed bird family tree ever, spanning 93 million years and representing 92% of bird families species, using cutting-edge computational methods and a supercomputer to analyze vast amounts of genomic data.
- The study revealed that modern bird groups appeared within a 5-million-year window after the dinosaur extinction 66 million years ago, with early birds experiencing rapid increases in population size, evolution speed and brain size during this time.
- The researchers identified a new group of birds called Elementaves, which includes diverse birds found in the air, on land, and in the sea, but couldn’t resolve the evolutionary position of the unique hoatzin bird from South America.
- The ongoing research aims to sequence the genomes of all living bird species and has important implications for conservation efforts, particularly for evolutionarily distinct and endangered bird species.
Scientists have created the largest and most detailed bird family tree ever, showing how various species are related to each other and how they evolved over the past 93 million years.
The study, published in Nature, looked at the genomes of 363 bird species, representing 92% of all bird families.
“Our goal is to reconstruct the entire evolutionary history of all birds,” said study co-author Siavash Mirarab, a professor of electrical and computer engineering at the University of California, San Diego.
To build this family tree, the team used genomic data from more than 60,000 genomic regions, cutting-edge computational methods developed by engineers at UC San Diego, and a supercomputer.
Modern bird groups, it turns out, appeared within a small window of 5 million years after the mass extinction of dinosaurs 66 million years ago. The researchers found that these early birds experienced rapid increases in population size, evolution speed and brain size during this time.
“After an asteroid hit the Earth, birds made the most of the opportunities that opened up after these extinctions to become one of the most diverse and successful groups of animals,” study co-author Jacqueline Nguyen, a paleontologist at Flinders University in Australia, told Mongabay.
The scientists also found it was more important to study many genes from each bird species than to study fewer genes from more species. However, studying more species did help them figure out when different bird groups evolved.
“We found that it was more important to sample many genetic sequences from each organism than it was to sample from a broader range of species, although the latter method helped us to date when different groups evolved,” Josefin Stiller, a professor of biology at the University of Copenhagen and lead author of the Nature paper, said in a statement.
The study also identified a new group of birds called Elementaves, which includes birds that are successful on land, in the air and in the water. This group includes penguins, pelicans, swifts, hummingbirds and shorebirds.
The name Elementaves “is inspired by the four ancient elements of air, earth, water, and fire,” Nguyen said. “We named this group Elementaves because it includes birds that are found in the air, on the land, and in the sea. Some of the birds in this group have names relating to the sun, which represents fire.”
Despite the huge amount of data used in the study, one mystery remains unsolved: The researchers couldn’t figure out how the hoatzin (Opisthocomus hoazin), a unique bird found only in South America, is related to other birds. It’s “the sole survivor of its lineage,” Nguyen said. “Even with huge amounts of genome data, its position in the bird family tree has been challenging to resolve and remains a mystery.”
The research is part of the Bird 10,000 Genomes (B10K) Project, which aims to sequence the genomes of all living bird species and involves scientists from many countries working together for nearly a decade now.
The team plans to continue its efforts to construct a complete picture of bird evolution. Biologists are working on sequencing the genomes of additional bird species in the hopes of expanding the family tree to include thousands of bird genera.
Having a good understanding of how birds are evolutionarily related to each other is important for conservation, Nguyen said. “Bird species that are evolutionarily distinct and endangered could be prioritized for conservation efforts,” she said, “because if these species go extinct, their entire branch of the bird family tree would be lost.”
Banner image of a Hoatzin in the Amazon. Photo by Rhett Ayers Butler.
Liz Kimbrough is a staff writer for Mongabay and holds a Ph.D. in ecology and evolutionary biology from Tulane University, where she studied the microbiomes of trees. View more of her reporting here.
Citation:
Stiller, J., Feng, S., Chowdhury, A. A., Rivas-González, I., Duchêne, D. A., Fang, Q., … Zhang, G. (2024). Complexity of avian evolution revealed by family-level genomes. Nature, 1-3. doi:101038/s41586-024-07323-1