Changchengia is a genus of possible alga from the early-mid Proterozoic.

In C. stipitata the thallus is usually ribbon-shaped or lanceolate with folded and lamellose margins, with the widest point in the middle and tapering towards the base and tip.

However, fossils from the Chuanlinggou Formation are more ovoid or obcordate in shape, alongside tapering holdfasts.

The base is obtuse and contacts with a long and linear parastem, which itself connects to a holdfast.

[2] However, a conspicuous difference between the two is that Tuanshanzia has no parastem, and instead its thallus slowly narrows towards the holdfast.