Эрдэмтэд 150 сая жилийн тэртээ амьдарч байсан, шувуу болон үлэг гүрвэлийн шинжийг хослуулсан шинэ зүйлийн махчин амьтны үлдэгдлийг илрүүлжээ.
Хятадын зүүн өмнөд нутгийн Жэнхэ бүсээс олдсон Yuezhuornis yangyuanensis хэмээх энэхүү амьтан нь хэрээний дайтай хэмжээтэй, ойролцоогоор 0.8 кг жинтэй байсан болохыг аравдугаар сарын 14-нд нийтлэгдсэн судалгаагаар тогтоов. Уг олдвор нь шувуудын хувьсал болон нисэх чадвар хэрхэн хөгжсөнийг ойлгоход чухал ач холбогдолтой юм. Судлаачдын үзэж буйгаар, уг амьтан нь нисэх чадваргүй, харин газар дээр гүйж ангуучлахад бүрэн зохицсон махчин байжээ.
Хятадын Шинжлэх ухааны академийн судлаач Мин Ван болон түүний баг уг олдворыг Velociraptor зэрэг махчин үлэг гүрвэлийн шинж чанаруудтай төстэй болохыг тэмдэглэжээ. Тухайлбал, энэ амьтан нь хөлийн хуруундаа хадуур хэлбэрийн хүчирхэг хумстай, урд мөч нь хойд мөчөөсөө гуравны нэгээр богино байсан нь орчин үеийн шувуудын нисэхэд зориулагдсан урт далавчтай эрс ялгаатай юм. Мөн гавлын яс болон шүдний бүтэц нь махчин амьдралын хэв маягтай байсныг гэрчилж байна.
Судалгааны баг уг амьтны биеийн бүтцийг одоо амьдарч буй 377 зүйлийн шувуудтай харьцуулан судалсны дүнд түүнийг нисэх чадваргүй, газрын амьдралд илүү дасан зохицсон гэж дүгнэжээ. Гэсэн хэдий ч эволюцийн хувьд энэ амьтан нисэх чадвартай гэж үздэг Archaeopteryx-ээс илүүтэйгээр орчин үеийн шувуудтай холбогддог байна.
Палеонтологич Фернандо Новасын тайлбарласнаар, нисэх чадвар нь шувуудын өвөг дээдэс болох махчин үлэг гүрвэлийн бүлгүүдэд нэг бус удаа, харилцан адилгүй хэлбэрээр үүссэн байж болох юм. Энэхүү олдвор нь эртний шувуудын экологийн болон морфологийн олон талт байдал нь урьд өмнө төсөөлж байснаас илүү өргөн хүрээтэй байсныг харуулж байна. Эрдэмтэд шувууд болон үлэг гүрвэлийн хоорондох ялгаа нь эртний төсөөллөөс хавьгүй бага болохыг энэ судалгаагаар онцоллоо.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
A small, crow-sized bird that lived about 150 million years ago in what is now southeastern China seems to have been a land-based hunter with a formidable toe claw. Named Yuezhuornis yangyuanensis, it mixed traits of birds with those of predatory dinosaurs such as Velociraptor. Its description, published in Nature, suggests the earliest birds led more varied lives than anyone had recognized.
Jurassic birds first emerged between 150 million and 148 million years ago, and their fossils are rare. For that reason, experts are only starting to understand how early birds diversified and developed the ability to fly.
The new species turned up in 2024 in the Upper Jurassic Zhenghe Fauna, a fossil assemblage in southeastern China. It lived roughly when birds began to show up in the fossil record, and the team reported its findings on Wednesday, October 14.
A Small Hunter with a Sickle Claw
Analysis of the fossilized skeleton showed an animal of about 1.8 pounds (0.8 kilograms). Min Wang, a researcher at the Chinese Academy of Sciences, told Live Science by email: “It was probably as large as a crow.”
The creature shared features with predatory Deinonychosauria such as Velociraptor, famous for sickle-shaped toe claws. It had hyperextensible toes, and its forelimbs were roughly one-third shorter than its hind limbs. Its short forelimbs ran against the trend. Modern birds and many Jurassic paravians, which include bird-like dinosaurs, bird ancestors and modern birds, have long forelimbs that help wings generate lift for takeoff.
Slender cranial elements and sparsely spaced teeth point the same way, and so do curved, claw-like toes able to secure prey. Together, they suggest meat was on the menu.
Part Bird, Part Dinosaur
According to Wang, the teeth, the pectoral girdle and above all the hyperextensible second toe resemble those of dinosaurs, while the slender skull bones and the bird-like pelvis are comparable to early birds. This mix of features suggests, he added, that:
“The morphological gap between birds and dinosaurs is much smaller than we thought.”
The study also compared its limb proportions with those of 377 living bird species. The closest matches were terrestrial birds. Wang suggested the animal was flightless, but not specialized for life in trees or for wading in the region’s swamps. It was a small carnivore with pheasant-like proportions and well adapted for running. “I think there are no directly comparable modern birds,” he said.
A New Way to Take Flight
The mosaic of features hints that the bird occupied an ecological niche rarely used by early birds, and that there was no systematic progression toward flight optimization, Wang said. Despite being flightless, the animal is placed closer on the evolutionary tree to modern birds than to Archaeopteryx, one of the world’s first proto-birds, which lived about 150 million years ago and is thought to have been able to fly.
That adds to a wider picture. As explained by Fernando Novas, a paleontologist at the Felix de Azara Natural History Foundation in Buenos Aires who was not involved in the study:
“The ability to fly arose not once, but several times among disparate groups of carnivorous dinosaurs that are closely related to birds.”
Y. yangyuanensis seems to have taken a different road, Novas noted, avoiding the flying ways of its relatives. In his accompanying Nature article, he listed early birds, the scansoriopterygid dinosaurs, which had membranous folds like the wings of bats, and the four-winged microraptors as groups in which flight appeared.
“It highlights the extraordinary breadth of ecological and morphological diversification that took place close to the origins of avialans,” said Wang.
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