The following new corticolous species are described. Thelopsis cruciata Aptroot & M. Cáceres, with an olive-green thallus, immersed red-brown perithecia and c. 50–100 cruciate ascospores per ascus, 7–10×4–7 µm, from Brazil. Topelia argentinensis Aptroot, L. I. Ferraro & M. Cáceres, with a verrucose, partly almost isidiate, greenish grey thallus, immersed pinkish perithecia and 8 uniseriate muriform ascospores per ascus, 12–17×7–11 µm, from Argentina. Topelia tetraspora Aptroot & M. Cáceres, with a c. 0·1–0·6 mm thick layer of coralloid to usually flattened, irregularly palmately branched isidia c. 0·05 mm diam., ascospores 15–19×2–6-septate, muriform, ellipsoid, 39–50×11–16 µm, only up to 4 per ascus maturing, from Brazil. Thelopsis inordinata is reported for the first time from South America, from Guyana. A key is given to all currently known species of Topelia and Thelopsis. The distinction between these genera has become arbitrary with the recent addition of more or less intermediate species.