Changyuraptor

''Changyuraptor '' is a genus of "four-winged", predatory dinosaurs. It is known from a single fossil specimen representing the species ''Changyuraptor yangi'', which was discovered from Early Cretaceous (125 million year old) deposits in Liaoning Province, China. ''C. yangi'' belongs to the group of dromaeosaurid theropod dinosaurs called the Microraptoria.

At the time of its discovery, ''C. yangi'' was the largest four-winged dinosaur known and among the largest Mesozoic flying paravians, volant true birds seldom approaching its size.Nicholas R. Longrich; David M. Martill; Brian Andres (2018). "Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary". PLOS Biology. 16 (3): e2001663.

Description

Analysis of the fossil at the University of Cape Town, South Africa reveals that the specimen was a fully grown adult, approximately long and estimated to weigh , roughly the size of a turkey. These dimensions make ''Changyuraptor'' the largest four-winged microraptorine known, exceeding previously known specimens in size by at least 60%.

Like other microraptorines, ''Changyuraptor'' had feathers all over its body, including forelimbs and hindlimbs, which gives the appearance of having two pairs of wings. The presence of long feathers on all four limbs also suggests that these dinosaurs could fly.

The dinosaur's tail is long and feathered, with end feathers up to long, equalling approximately 30% of the length of the animal's skeleton. This length exceeds the previous record length of for feathers from non-avian dinosaurs. The elongated tail feathers are thought to have helped provide softer and safer landings. They could have controlled pitch, a feature useful for a heavier animal, that would have attained a faster gliding speed.

While elongated feathers on the hindlimbs were present in many early birds, such as ''Archaeopteryx'', the morphology of microraptorines suggests a different aerodynamic model from that of modern birds, which have characteristically bald legs and exhibit stable flight using two wings only.

''Changyuraptor'' is thought to have existed alongside a variety of predatory and herbivorous dinosaurs of the Jehol Biota, including ''Yutyrannus'', in moist temperate forest, primarily vegetated by ginkgos and conifers, with hot, dry summers and frosty winters.

Discovery

The fossil, holotype HG B016, was discovered by farmers near Xijianchang in the Early Cretaceous fossil deposits, the Yixian Formation, of the Jehol Biota, located in the Liaoning province of China. From 2012 it was studied by an international team of scientists led by Dr. Luis Chiappe, Director of the Dinosaur Institute Department at the Natural History Museum of Los Angeles County. The holotype consists of a rather complete skeleton with skull, compressed on a plate and counterplate. It shows extensive remains of the integument in the form of pennaceous feathers. In 2014, the specimen was described as the new genus and species ''Changyuraptor yangi''. The generic name of the dinosaur combines the Chinese words for "long feather", 長羽 (''cháng yǔ''), with Latin ''raptor'' ("robber", "seizer"). The specific name honours researcher Professor Yang Yandong.

The Jehol Biota are found in the richest fossil beds for feathered dinosaurs in the world which have yielded notable species such as '' Yutyrannus huali'', a feathered tyrannosauroid with a length of and the largest feathered dinosaur known to date.

In 2003 ''Microraptor'', a raven-sized dinosaur, approximately in weight, was the first of the microraptorines to be discovered. It shared with species such as ''Anchiornis'' and ''Xiaotingia'' large feathered limbs and elongated bony tails with long tail feathers. These features caused experts to hypothesize that miniaturisation was an essential evolutionary step to enable flight. ''Changyuraptors larger size and weight contradicts that hypothesis. ''Changyuraptor'' is also the second four-winged dinosaur to be discovered after ''Microraptor''. ''Changyuraptor'' and other microraptorines add to the evidence that dinosaurs had evolved a host of morphological features and behaviours such as feathers, hollow bones, nesting behaviour, and possibly flight, before they evolved in birds.

See also

* Timeline of dromaeosaurid research

References

{{Taxonbar, from=Q17363721

Early Cretaceous dinosaurs of Asia
Microraptorians
Feathered dinosaurs
Fossil taxa described in 2014
Paleontology in Liaoning