#ostreidae

[uncharismatic-fauna]

Uncharismatic Fact of the Day

Get ready, get set, filter! Oysters are masters of removing algae, detritus, and plankton from the water, and none do it faster than the Hong Kong oyster. Despite reaching only 20 cm (7.8 in) in length, each individual is capable of filtering up to 30 L (7.9 gal) of water every hour!

(A Hong Kong oyster (Magallana hongkongensis) reef by Marine Thomas)

[animalids]

Cockscomb oyster (Lopha cristagalli)

Photo by Nick Hobgood

[drhoz]

#3814 - Flemingastrea wollastoni

A widespread genus of large extinct oyster, sometimes considered a subgenus of Ostrea, and named after British paleontologist and naturalist Andrew Fleming (1822–1892), who did a lot of work on the geology of India, which is just one of the places the oysters have been found. I don't know who Wollaston was. His oyster could reach 160mm in size.

This one was endemic to the shallow seas around New Zealand, but the various species were widespread around the world, from the Upper Cretaceous to the Eocene, and are quite useful index fossils, and markers for when sea levels rose to flood freshwater habitat. Although the way the shape and spikyness of the shells differs between young and old specimens doesn't help with ID.

Museum of the Vanished World, Duntroon,  Aotearoa New Zealand.

[drhoz]

#3052 - Dendostrea folium - Foliate Oyster

Also known as the Leaf Oyster.

Found on coastlines of the Indo-West Pacific, growing to up to 100 mm in length. Often found growing in stacks on coral branches, mangrove sticks, or other elongate material intertidally and subtidally. Floating ropes and drift nets are also popular. The lower valve develops small finger-like extensions like to clasp elongate substrate items.

Leighton Beach, WA Naturalists Club Centenary Beach Walk, Perth, WA

[drhoz]

While confronting head-on the conflicting claims about the calamities that struck down the world's richest oyster grounds, this fresh perspective re-evaluates the roles of three groups that combined to kill off most of the oysters in the Chesapeake Bay. The roles of watermen who fish the oysters, oyster farmers who grow them, and scientists who study them, are illuminated by recent research in science labs, along the bottom of the Bay and deep in long-forgotten historical archives. Directed and produced by Michael W. Fincham, Maryland Sea Grant College. Presented by Maryland Public Television.

[drhoz]

#2498 - Crassostrea ingens - Giant Oyster

A giant oyster species, with shells exceeding 30cm in length, that was abundant in shallow seas around New Zealand 2.5 million years ago. Despite the age, many of the fossils still have a reddish-purple mark where the adductor muscle was attached.

Whanganui Regional Museum, New Zealand

[crudlynaturephotos]

[drhoz]

#993 - Ostrea angasi - Southern Mud Oyster

Also known as Southern Flat Oyster. Native to southern Australia, with triangular to round, unequal-shaped valves. The upper valve is thick, heavy, rounded but compressed, flat to concave, and is sculptured with irregular, scaly, concentric growth-scales called lamellae that often form a wavy shell margin. They get up to 180mm across - this is just a baby.

Grows in sheltered coasts or silty estuaries, from 1 to 30m depth, either attached to rocks and shells or simply sitting on the muddy seafloor. These days the species is farmed, after the extensive oyster reefs that had existed prior to European colonisation were mostly eradicated due to over-exploitation during the 19th and early 20th Centuries, although an epidemic of unknown cause also made the population crash in some areas. Prior to that, they must have been very common around Sydney, given how big the giant midden mounds left by the Aboriginal inhabitants are.

Ostrea angasi is named after George Fife Angas, an businessman associated with the early foundation and prosperity of South Australia.

Munster, Perth