![\"Life](\"https:\/\/cdn.sci.news\/images\/enlarge13\/image_14899_1e-Zhengheornis-buyu.jpg\")
<\/a><\/p>\nLife reconstruction of Zhengheornis buyu. Image credit: Chung-Tat Cheung.<\/p>\n
Modern birds are unique among vertebrates in having a short tail capped by a fused clump of bone called the pygostyle, which anchors their fan of tail feathers and is essential to flight.<\/p>\n
Their dinosaur ancestors, by contrast, had long, bony tails with dozens of vertebrae.<\/p>\n
How and when that transition happened has been difficult to pin down, largely because so few fossils capture birds in an intermediate stage.<\/p>\n
The newly-identified bird species, Zhengheornis buyu, appears to be one of those missing pieces.<\/p>\n
\u201cBecause long-tailed and short-tailed birds appeared nearly simultaneously in the early fossil record without clear intermediates, evolutionary biologists have long argued that a transitional species having an abbreviated but entirely unfused bony tail was biologically improbable and unlikely to have ever existed,\u201d said Dr. Zhonghe Zhou, a paleontologist with the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences.<\/p>\n
The holotype specimen of Zhengheornis buyu was found in 2024 in the Nanyuan Formation near Yangyuan village in Zhenghe country in China\u2019s Fujian province.<\/p>\n
The fossil dates 148-150 million years back to the end of the Jurassic period, when some of the earliest birds were beginning to diversify.<\/p>\n
It is the fourth bird taxon now known from what paleontologists call the Zhenghe Fauna, joining Fujianvenator<\/a>, Baminornis<\/a> and an incomplete specimen represented by a single furcular (wishbone).<\/p>\n Based on the circumference and length of its thigh bone, the authors estimate a body mass of 74 to 163 grams \u2014 smaller than the diminutive specimen long held up as the smallest known Archaeopteryx<\/a>.<\/p>\n \u201cThe holotype of Zhengheornis buyu is, to our knowledge, the smallest adult individual of non-pygostylian theropods known thus far,\u201d they said.<\/p>\n The holotype specimen of Zhengheornis buyu. Image credit: Wang et al., doi: 10.1126\/sciadv.aeb5202.<\/p>\n Zhengheornis buyu\u2019s tail contains just 15 vertebrae \u2014 far fewer than the 23 to 24 found in Archaeopteryx or the more than 30 in other early bird relatives \u2014 yet those vertebrae remain separate rather than fused into a pygostyle.<\/p>\n<\/a><\/p>\n