More than 120 million years ago, a small feathered dinosaur lived in what is now Liaoning Province, China. Fossils from this region have provided scientists with an extraordinary look at feathered dinosaurs and the evolutionary history connecting dinosaurs and modern birds.
Now, paleontologists have described another microaptorine from the region. Known from an almost complete skeleton, this little raptor provides another fascinating piece of the dinosaur-bird puzzle.
Meet a Microaptorine
Microaptorines were small theropod dinosaurs closely related to the evolutionary lineage that eventually produced modern birds.
Some members of this group are especially famous for having long flight feathers associated with both their forelimbs and hind limbs, giving them what is sometimes described as a four-winged appearance.
These unusual dinosaurs lived during a remarkable period in bird evolution, when many different combinations of feathers, wings, body shapes, and other birdlike characteristics were appearing among small theropods.
A Remarkably Complete Skeleton
The newly described raptor from Liaoning is known from an almost complete skeleton, giving paleontologists an opportunity to examine a large number of anatomical characteristics.
Researchers compared more than 200 traits preserved in its skeleton and found numerous characteristics shared with modern birds.
These similarities are important because modern birds did not suddenly appear with an entirely new collection of features. Instead, many characteristics we associate with birds developed gradually among their dinosaur ancestors and close relatives.
Dinosaurs Were Becoming Birdlike
The fossil record has revealed an increasingly complex picture of the transition between non-avian dinosaurs and birds.
Feathers, for example, appeared among dinosaurs before the origin of modern birds. Over evolutionary time, feathers took on different forms and functions, eventually becoming part of the sophisticated flight systems seen in birds today.
Other birdlike characteristics also appeared at different points in theropod evolution.
Rather than a single moment when a dinosaur suddenly became a bird, scientists see a long evolutionary history in which different traits accumulated and changed across many dinosaur groups.
Why Four-Winged Dinosaurs Matter
Microaptorines are particularly interesting because their anatomy helps scientists investigate the early evolution of flight.
Their feathered forelimbs and hind limbs show that dinosaurs experimented with body plans very different from those of living birds. Studying these animals can help paleontologists explore how behaviors such as gliding and eventually powered flight may have developed.
Each newly discovered species provides another opportunity to compare these anatomical features and better understand how flight evolved.
Dinosaurs Never Completely Disappeared
Perhaps the most remarkable part of the dinosaur-bird story is that dinosaurs are not entirely extinct.
Modern birds are the surviving descendants of theropod dinosaurs.
From tiny hummingbirds to enormous ostriches, the birds living around us today represent the continuation of an evolutionary story that began deep in the age of dinosaurs.
And fossils of small feathered raptors from places like Liaoning are helping scientists uncover more of that story, one skeleton at a time.
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