Wikipedia:Main Page history/2020 December 19
From today's featured articleAchelousaurus was a ceratopsid dinosaur that lived about 74.2 million years ago, during the Late Cretaceous. The first fossils of the genus were collected from the Two Medicine Formation in the U.S. state of Montana in 1987. Mainly known from skull material, Achelousaurus was about 6 m (20 ft) long, with a weight of about 3 tonnes (3.3 short tons). It had a large head with a hooked beak, and a bony neck-frill with a pair of long, curved spikes. In the places where other centrosaurines often had horns, Achelousaurus had bosses (roundish protuberances) above the eyes and on the snout that may have been used in fights and for display. It has been suggested that Achelousaurus was a transitional form between Einiosaurus (which had spikes but no bosses) and Pachyrhinosaurus (which had larger bosses), though this is debated. As a ceratopsian, Achelousaurus would have been a herbivore. It appears to have had a high metabolic rate, though lower than that of modern mammals and birds. (Full article...)
Recently featured:
Did you know ...
|
In the news
On this day
More anniversaries:
|
Today's featured picture
NGC 6357 is a diffuse nebula in the constellation Scorpius. This composite image of the nebula contains X-ray data from the Chandra X-ray Observatory and the ROSAT telescope (purple), infrared data from the Spitzer Space Telescope (orange), and optical data from the SuperCosmos Sky Survey (blue). Radiation from hot, young stars is energizing the cooler gas in the clouds that surround them. Often known as the Lobster Nebula, the astronomical object has also been termed the Madokami Nebula by fans of the anime Madoka Magica due to its supposed resemblance to the main character. Scientists at the Midcourse Space Experiment prefer the name War and Peace Nebula, because the bright, western part resembles a dove, while the eastern part looks like a skull in infrared images. Photograph credit: NASA
Recently featured:
|
Other areas of Wikipedia
- Community portal – Bulletin board, projects, resources and activities covering a wide range of Wikipedia areas.
- Help desk – Ask questions about using Wikipedia.
- Local embassy – For Wikipedia-related communication in languages other than English.
- Reference desk – Serving as virtual librarians, Wikipedia volunteers tackle your questions on a wide range of subjects.
- Site news – Announcements, updates, articles and press releases on Wikipedia and the Wikimedia Foundation.
- Village pump – For discussions about Wikipedia itself, including areas for technical issues and policies.
Wikipedia's sister projects
Wikipedia is hosted by the Wikimedia Foundation, a non-profit organization that also hosts a range of other projects:
Free media repository
Wiki software development
Wikimedia project coordination
Free textbooks and manuals
Free knowledge base
Free-content news
Collection of quotations
Free-content library
Directory of species
Free learning resources
Free travel guide
Dictionary and thesaurus