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Physella acuta is a species of small, air-breathing freshwater snail in the family Physidae of North American origin. Like other physids, P. acuta presents a sinistral (left-coiling) shell as well as a unique set of muscles called the physid musculature that allows it to rapidly twist the shell as a defence mechanism. Physella acuta is invasive outside its native range. Its first introduction outside North America likely occurred through the 18th-century cotton trade to Europe, with later spread mainly through the aquarium trade. The species can occupy diverse freshwater habitats and tolerates polluted as well as oxygen-poor environments. Due to its high reproductive rate and tolerance to habitat degradation, it frequently outcompetes native snail species. In aquariums, P. acuta is usually introduced through ornamental plants and can become a "nuisance snail" due to its rapid reproduction. However, a controlled population can help clean up organic leftovers and control algae. (Full article...)

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Did you know ...

Statue of Pope John Paul II

... that a monument to Pope John Paul II (pictured) was cast using more than seven million donated keys?
... that the United States Armed Forces funded a radio station on Ascension Island that transmitted from an extinct volcano?
... that John Laugharne suddenly died the night after his re-election in 1715?
... that The Fantod Pack, a set of divination cards, predicts only misfortune for its users, including "unstable furniture", "misplaced confidence", and "worms"?
... that author and sugarcane cutter John Naish was critical of the sugar industry's role in the oppression of Indigenous Australians?
... that 2,920 gold coins, a gold chain from the Renaissance period, three gold medals, and an engraved copper casket were found by a construction worker?
... that less than a year after the owner of a Missouri TV station declared that "cancellation of a network affiliation is almost unheard of", his station's affiliation was canceled?
... that one journalist said that the only reason to go to Bastardstown is to say that you have been there?
... that a Golkar official claimed that he "would run around town naked" if Laurentius Say survived two terms as regent of Sikka?

In the news

Annita Demetriou

The Democratic Rally, led by Annita Demetriou (pictured), wins the most seats in the Cypriot legislative election.
American jazz saxophonist Sonny Rollins dies at the age of 95.
In auto racing, Felix Rosenqvist wins the Indianapolis 500.
A suicide bombing targeting a shuttle train in Quetta, Balochistan, Pakistan, kills at least 47 people.
In association football, the Women's Champions League concludes with Barcelona defeating OL Lyonnes in the final.

On this day

May 28: Menstrual Hygiene Day; Republic Day in Armenia (1918); Independence Day in Azerbaijan (1918)

William Knox D'Arcy

621 – Tang forces led by Li Shimin defeated and captured Dou Jiande at the Battle of Hulao in the civil war that followed the collapse of the Sui dynasty.
1608 – Italian composer Claudio Monteverdi debuted his second opera L'Arianna, now one of his lost works, at a royal wedding in Mantua.
1901 – Mozaffar ad-Din, Shah of Persia, granted exclusive rights to prospect for oil in the country to businessman William Knox D'Arcy (pictured).
1940 – Second World War: Belgium surrendered to Nazi Germany, ending the Battle of Belgium.
2016 – Harambe was shot and killed after grabbing a three-year-old boy in his enclosure at the Cincinnati Zoo and Botanical Garden, drawing widespread criticism and inspiring internet memes.

Li Jiji and Kong Qian (d. 926)
Jacopo Riccati (b. 1676)
Liam O'Brien (b. 1976)
Risi Pouri-Lane (b. 2000)

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Today's featured picture

The hoatzin (Opisthocomus hoazin) is a tropical bird found in the Amazon basin and the Orinoco Basin in South America. It is the only extant species in the family Opisthocomidae. A folivore, the hoatzin eats the leaves of the plants that grow in its marshy and riverine habitat. Its digestive system supports fermentation and effective breakdown of plant matter, a trait typically found in ruminants such as cattle. Because of aromatic compounds in the leaves it consumes and the fermentation required to digest them, the hoatzin has a manure-like odor, giving it a local nickname of stinkbird. It is a noisy bird and makes a variety of hoarse calls, including groans, croaks, hisses and grunts. Its chicks feature primitive claws on two of their wing digits, which they use immediately after hatching to move around tree branches. The hoatzin is believed to remain fairly common in a large part of its range, but its population is likely decreasing due to habitat loss. It is the national bird of Guyana. This hoatzin was photographed on a branch above the Napo River, a tributary of the Amazon River, in northeastern Ecuador.

Photograph credit: Charles J. Sharp

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