Paleontologists are always looking for vast new caches of clues about ancient life but rarely expect to find them. Fossil discoveries tend to come piece meal, one fragment at a time, so we were unprepared for the onslaught of fossils from Liaoning Provincein northeastern China.
The story began in the early 1990s, when Chinese researchers began unearthing intriguing land animals: first a primitive toothed bird, then a more advanced one. Then rumors began to circulate about strange dinosaurs covered with birdlike feathers. Now it seems as if there are more kinds of these creatures than we can count. Dinosaurs everywhere have been reevaluated, even to the extreme of considering that such familiar ones as Tyrannosaurus rex were probably feathered, at least for part of their lives.
During the Early Cretaceous, between 110 million and 140 million years ago, Liaoning was a remarkable place—covered by forests, riddled with lakes, and populated with a rich variety of animal and plant life. Distant volcanoes rained down fine-grained ash that deposited on the bottoms of ponds and lakes, yielding exceptionally well-preserved fossils. Local eruptions, meanwhile, may have triggered catastrophic die-offs, as suggested by the large groups of animals found together in some rocks. Collectively, the remains displayed on these pages tell much about the lives that dinosaurs lived, the origin of bird flight, the ecosystems during the ageof the reptiles, and the nature of evolution itself.
Dave the Dinosaur, a 2.5-foot-long dromaeosaurfrom Liaoning Province, China, is one of the finest dinosaur specimens ever discovered. The creature’s remains were trapped between two layers of fine paper shale, preserving the feathers that covered its entire body. Such dinosaurs could not fly, since their forelimbs were too short; their feathers most likely evolved as thermal insulation. Recent fossil discoveries have resonated throughout Chinese culture, as evidenced by the giant reconstruction of Sinraptor posed outside the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing.
Sinosauropteryx, unearthed from Liaoning in 1996, was the first dinosaur to show clear signs of feathers. It soon sparked a controversy. Some skeptics interpreted the outline above the skull as a fleshy crest, not a covering of protofeathers, but close examination revealed similar featherlike filaments over the animal’s entire body. The discovery of feathered dromaeosaurs clinched the direct link between birds and dinosaurs.
Archaeoraptor is an unfortunate product of the cottage industry of fakery spawned by the brisk trade in fossils from Liaoning. This bizarre creation, looking like a hungover rooster, is a composite of 88 pieces taken from several different fossils. It fooled the private Dinosaur Museum in Blanding, Utah, which paid $80,000 for the smuggled fossil. A reconstruction appeared in the pages of National Geographic; the magazine issued a retraction two months later. The main parts of Archaeoraptor are the tail of a Microraptor and the body and skull of a previously unknown bird, named Yanornis in a 2002 Nature paper entitled “Archaeoraptor’s Better Half.”
Shenzhousaurus is a spectacularly preserved example of an ostrich dinosaur—bipedal, long-legged, long-necked, usually toothless animals that resemble modern ostriches. This specimen has teeth, suggesting it is a very primitive form. It lies in a classic death pose, with the head pulled back over the body because of the contraction of the strong nuchal ligament in the neck. Identical poses occur among modern birds. A long neck accentuates the effect.
A fossil store in the village of Lingyuan is one of many that have sprung up since China’s fossils garnered fame. Such large dealers have a sophisticated network of contacts in the countryside, and some operate on both sides of the law. Anticorruption efforts are aimed at dismantling a complex web of smugglers who sell Chinese fossils around the world. Meanwhile, new small museums have sprung up in Dalian, Beipiao, and other cities; some of them are sending people abroad to study international curatorial standards and apply those standards locally. The new Liaoning Protection Bureau is also making it somewhat easier for farmers to be lawfully reimbursed for any specimens they find.
Fine FurMaotherium, a mouse-size primitive mammal, resembles a flattened rat on a New York street. Volcanic ash settling at the bottom of a pond turned into fine-grained paper shale, squashing the creature’s remains while preserving such fine details as the impression of its fur. Some would argue that many of the mammals of Liaoning are not really mammals at all because they are only distantly related to modern mammal groups.
Hyphalosaurus, a lizardlike aquatic predator with big eyes, a small head, and a ridiculously long neck and tail, is the most common nonfish fossil souvenir on China’s curio market. Liaoning’s rocks have yielded thousands of these creatures. Often, many hyphalosaurs are found on the same slab—a sure sign of a catastrophe. Somehow this one met its fate along with a baby turtle.
The extinct insect Ephemeropsis is probably the most abundant fossil in the Yixian Formation, a mile-thick layer of sediment containing most of the great finds from Liaoning. This is an aquatic larval form. Nearby rocks have yielded ants, dragonflies, cicadas, cockroaches, spiders, and beetles.
Fossil hot zone
Rich, fossil-bearing rocks extend from North Korea through China’s Liaoning Province and into Inner Mongolia. Within Liaoning, the hottest discoveries have come from the regions between the cities of Shenyang, Jinzhou, Chaoyang, and Beipiao. Fossil organisms found there are known as the Jeholbiota, named after the city that was the seat of the Qing emperors’ summer palace.
Herringlike Lycoptera and other ancient fish were discovered in Liaoning by Japanese scientists during the occupation of northern China. Most fish fossils are flat, monochromatic carcasses, but the ones here often preserve stripes, spots, and body outlines. The presence of pattern and color on many Liaoning fossils is one of their most spectacular attributes. What we see is a film laid down by the bacterial decomposition of different pigments in the scales, skin, feathers, and internal organs of the animal.
Frogs are plentiful in today’s China but are rare in the fossil beds of Liaoning. The few examples uncovered so far do not fit cleanly into familiar evolutionary sequences. This strange-looking creature is Mesophryne, a frog so unusual that it cannot be definitely assigned to any known group.