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By looking at this newly emerged bird, a 精品SM在线影片-led research team found an 鈥榚volutionary shortcut鈥� for speciation

Not all species may travel the same path to existence, at least according to new findings from the 精品SM在线影片 and collaborators.

This new research, , looked at a newly discovered, endangered songbird located only in South America鈥攖he Iber谩 Seedeater鈥攁nd found that this bird followed a very rare evolutionary path to come into existence at a much faster pace than the grand majority of species.

By comparing this bird to a closely related neighbor (the Tawny-Bellied Seedeater) in the same group (the southern capuchino seedeaters), the researchers determined that genetic shuffling of existing variations, rather than new random mutations, brought this species into existence鈥攁nd their own behaviors are keeping them apart.

This species is one of only two known examples across the globe to have traveled this path, challenging the typical assumptions of how new species form.听

鈥淥ne of the aspects of this paper that makes it so cool is that we were able to address this question of how the Iber谩 Seedeaters formed from multiple different perspectives,鈥� said Sheela Turbek, a graduate student in ecology and evolutionary biology (EBIO) at 精品SM在线影片 and the study鈥檚 lead author.

鈥淣ot only did we collect on-the-ground data on who mated with one another and the identity of their offspring, but we also generated genomic data to examine how similar these two species are on a genetic level. We then zoomed out further to look at where the Iber谩 Seedeater fits in the context of the broader capuchino group.鈥�

鈥淢any studies will address one of these aspects or questions but not combine all of these different pieces of information into a single study.鈥�

The southern capuchino seedeaters are a group of recently evolved songbirds found throughout South America that is branching rapidly, with many of its species in the early stages of evolution. This family is best known for the dramatic variation with the males in terms of songs and plumage color, while the females are largely indistinguishable even to the most familiar researchers.

The Iber谩 Seedeater, the most recent member of this family, was first discovered in the remote, swampy grasslands of Iber谩 National Park in northern Argentina by study co-authors Adri谩n S. Di Giacomo and Cecilia Kopuchian from Centro de Ecolog铆a Aplicada del Litoral, Argentina, in 2001, and then described in scientific literature in 2016.

In that national park, though, are six other closely related species of capuchinos, including the Tawny-Bellied Seedeater, that breed closely beside each other. These species, despite occupying the same environment and eating the same food, rarely interbreed.

And so, researchers wondered why鈥攁nd how鈥攖he Iber谩 Seedeater even came to be.

They explored these questions in two ways: First, they looked at how this new species may have formed by examining the ways in which its DNA differs from the Tawny-Bellied Seedeater, and second, looking at what mechanisms might be preventing it from interbreeding with the other species that occur in the park.

To do that, Turbek went down to Argentina for the breeding season for three years, staying two and a half to three months at a time, searching for and monitoring nests, collecting blood samples from adults and nestlings, and then, in the final year, performed a behavioral experiment to see whether plumage or song played a role听in terms of species recognition.

鈥淭he field work involved in collecting the assortative mating and behavioral data is extraordinarily hard, which is why these kinds of datasets rarely exist. This study and publication are a testament to Sheela's skill and hard work in the field,鈥� said Scott Taylor, an assistant professor in EBIO at 精品SM在线影片, an author on the paper, and Turbek鈥檚 advisor.

What they found is that the two birds are closely related genetically, only distinguishable by the genes involved in plumage coloration. As well, they found that the males responded most aggressively to songs and plumage variations aligning with their own species.

This all means that the species could very well reproduce and hybridize鈥攖hey just choose not to, therefore reinforcing their own reproductive barriers.

On a broader level, though, when comparing the Iber谩 Seedeater to other capuchino species, the researchers found that the Iber谩 Seedeater shares genomic variants with other capuchinos in these regions, but the variants have been shuffled to form a unique combination, which, the researchers argue, could be an evolutionary shortcut that most likely underlies much of the diversity among the different subspecies of this family.听

"This is a really beautiful story about a process that we have never seen in quite this way before,"听says co-author Irby Lovette, director of the Fuller Evolutionary Biology Program at the Cornell Lab of Ornithology.听

"The classic and most common evolutionary model for new species is the accumulation of genetic mutations when those species are separated by a geographic barrier over perhaps millions of years. But here we found that genetic shuffling can happen quickly and without geographical isolation. It鈥檚 almost like 'instant speciation.'"

Leonardo Campagna, a research associate at the Cornell Lab of Ornithology and the senior author on the paper, agrees:

鈥淭his is the clearest example in birds of how reshuffling of genetic variation can generate a brand-new species."

The only other organism where this type of evolution has been seen, according to Turbek, is a group of fish found in Africa called the Lake Victoria cichlids.

鈥淚t鈥檚 interesting to see this mechanism operating in something as different as birds,鈥� Turbek commented.

While this study focused in part on the role of male behaviors, the researchers are very interested in taking it one step further, examining the role that female choice may also play in reproduction.

鈥淭here are many more questions that we have to address,鈥� Turbek said.

This research was funded by National Geographic, the American Genetics Association, the American Philosophical Society, the American Society of Naturalists, the Wilson Ornithological Society, the British Ornithologists鈥� Union, the American Ornithological Society, the Society of Systematic Biologists and the National Science Foundation.

Other researchers on the project include Melanie Browne with Centro de Ecologia Aplicada del Litoral in Corrientes, Argentina; Wesley M. Hochachka with the Cornell Lab of Ornithology; Dario A. Lijtmaer and Pablo L. Tubaro with Museo Argentino de Ciencias Naturales Bernardino Rivadavia, Buenos Aires, Argentina; Luis Fabio Silveira with Museu de Zoologia da Universidade de Sao Paulo, Sao Paulo, Brazil; and Rebecca J. Safran with 精品SM在线影片.