From today's featured articleOnychopterella was a predatory aquatic arthropod of the order of eurypterids, often called sea scorpions. Fossils of the species O. kokomoensis (pictured) and O. pumilus have been found in the United States, and fossils of O. augusti in South Africa. Onychopterella (from Greek for 'claw wing') lived from the Late Ordovician to the Late Silurian, from 444 to 422 million years ago. The head was almost rectangular, with bean-shaped compound eyes. The limbs were generally long and narrow with a spine on the tip, and the body was ornamented with small, pointed scales. Lengths ranged from 16 cm (6.3 in) for O. kokomoensis to 4 cm (1.6 in) for O. pumilus. Onychopterella was able to swim, and probably able to walk on the seabed with its spines and dig with its head. The best-preserved specimens of O. augusti show similarities to modern scorpions in their alimentary canal, limb musculature and respiratory system. (Full article...)
Recently featured:
Did you know ...
|
In the news
On this day
Anna Morandi Manzolini (b. 1714) · Joseph Wolf (b. 1820) · Cecil B. DeMille (d. 1959)
More anniversaries:
|
Today's featured picture
The underground station Rochusplatz on the Cologne Stadtbahn, a light rail system in the German city of Cologne. The station entrance is at the junction of Venloer Straße with Äußere Kanalstraße in the district of Ehrenfeld. It was opened in 1992 and consists of a mezzanine and one island platform with two rail tracks. The station was previously known as Äußere Kanalstraße, but was renamed to its present title on 15 December 2019. The system uses pairs of K5000/K5200 units built by Bombardier Transportation, which are almost identical to the M5000 trams used by Metrolink in Manchester, England. Photograph credit: Martin Falbisoner
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 materials and activities
Free travel guide
Dictionary and thesaurus