Terebratalia transversa or the North Pacific Lampshell is a species of marine brachiopod in the family Terebrataliidae.

[1][2] A two-valved shelled species, they are most frequently found in tidal habitats in the Pacific Northwest of the United States.

[4] Researchers find that the mesoderm found in Terebertalia larvae comes from the endomesoderm and develops close to the vegetal blastopore.

[6] During the development of this apical organ, the ciliated sections form together into a tuft with recessed rootlets that is made up of acetylated α-tubulin.

[6] Juveniles develop quickly after their A-P axis emerges due to Hox gene expression in the event referred to as "metamorphosis."

The point at which they are referred to as adults is when they have a clearly separated body from their old two-valved juvenile shell attached via a posterior pedicle.

The most significant muscle morphology in the species is referred to as the mantle margin, the tissues responsible for the development of their adult shell.

The outermost part of the shell is the primary layer which contains transversal sections of fibers pointing in various directions.

[11] Significant populations of Terebratalia transversa are located in the waters near the Pacific Northwest in the United States.

Specifically, scientists have collected the species by dredging in the area around the San Juan Channel off the coast of Washington, USA.

The shells of this species, when fossilized, help researchers find preserved isotopic signals that aid in uncovering molecular compositions of an old Paleozoic ocean.