Yoldia

Yoldia is a genus of marine bivalve mollusks belonging to the family Yoldiidae. These clams are characterized by their elongated, equivalve, and inequilateral shells, which are typically smooth and glossy. The shell's anterior end is usually rounded, while the posterior end tapers to a point. Yoldia species are found in a variety of marine environments worldwide, inhabiting soft sediments on continental shelves and slopes.

The genus Yoldia was described by William John Swainson in 1840. While many species have been described, the exact number and validity of some are subject to ongoing taxonomic research. Common characteristics include a prominent posterior gape, which allows for the extension of the siphons. These siphons are used for respiration and feeding, with Yoldia clams being deposit feeders that ingest organic matter from the seafloor. They play a role in bioturbation, mixing the sediment as they burrow.

Several species of Yoldia are of ecological importance, serving as a food source for various marine organisms. Some species may also have economic significance in certain regions, although they are not as widely harvested as other clam species. The distribution and abundance of Yoldia species can be influenced by factors such as water temperature, salinity, and substrate type. Their life cycle generally involves a planktonic larval stage before settling to the benthos.