#arcidae

Another Australian endemic, although the sources I checked disagree on whether it grows attached to the seafloor with byssus threads, or embedded in sponges.

The genus has been around since the Jurassic, in most parts of the world.

The strange curved shell of Trisidos tortuosa. A closed shell can be seen in this (example)

17/09/23 - Gastropoda: Trisidos tortuosa

AKA tūroro in te reo Māori.

First described by Edgar Albert Smith in 1915. Smith (1847 – 1916) was a British zoologist and malacologist, and his gravestone is distinguished by the Giant Clam shell on top of it.

Arcid clams endemic to New Zealand and the Chathams, where they live down to a depth of about 90m, usually attached to the underside of stones by byssus threads.