標題: Photo Gallery: Triassic Period [打印本頁] 作者:
路人甲 時間: 2008-4-24 08:10 PM 標題: Photo Gallery: Triassic Period
An artist's rendering shows hatchling nothosaurs heading for the safety of water as a hungry but terrestrial Ticinosuchus attacks near a lagoon in ancient Switzerland. Nothosaurs lived during the mid- and late Triassic period and were among the earliest reptiles to take to the sea. Because nothosaurs may have had to come ashore to lay eggs, the eggs and hatchlings would have been vulnerable to Ticinosuchus. Yet once the hatchlings reached deeper waters, they were safe—for the moment.
An artist's depiction shows a Herrerasaurus lurking in a forest in what is now Argentina as smaller animals hide in the undergrowth. Herrerasaur fossils are among the oldest ever discovered, dating back about 228 million years to the mid-Triassic.
An artist's depiction captures the burst of new life that occurred in the early- to mid-Triassic period. Massive extinctions at the end of the preceding Permian period allowed the plants and animals that survived to grow and diversify relatively free of competition and predators. These conditions gave rise to the dinosaurs, pterosaurs, and early crocodilians.
Chunks of petrified wood lay strewn in Arizona's Petrified Forest National Park. Most petrified trees here are of the species Araucarioxylon arizonicum, a towering conifer that grew in the humid, tropical lowlands of this region during the middle Triassic period, about 220 million years ago. Trees that fell here often landed in deep rivers, where they were quickly buried by sediment. Lack of oxygen inhibited decay, and heat and pressure over millennia turned the wood into solid quartz colored by impurities like iron, carbon, and manganese.
This middle-Triassic reptile found in Switzerland measures only about 9 inches (23 centimeters) in length. Called Pachypleurosaurus edwardsi, these primitive amphibious reptiles were nothosaurs, among the first reptiles to venture into the shallow seas of the Triassic.
Ichthyosaurs were big-eyed, dolphin-shaped marine reptiles that lived during the Triassic, Jurassic, and Cretaceous periods. This specimen, uncovered in the hills of Guizhou Province, China, was an early species that had a rather reptilian look; later species took on a more fishlike form.
A carver in Guizhou Province, China, sculpts a Keichousaurus hui fossil, referred to locally as "sea dragons," into a chunk of stone. The remains of these diminutive Triassic-era reptiles and many others are prominent and well-preserved in this region—one small mountain rich in fossils has been dubbed "Lurking Dragon Hill." In China, the dragon is a symbol of good luck, and replicas like these help to curb illicit fossil collecting.
From : Nationalgeographic作者:
Franco仔 時間: 2008-4-24 10:10 PM
