The specific epithet subargenteum refers to its similarity to another species, T. argenteum, which has been found in Costa Rica and Argentina.

Another species, T. africanum, shares some similarities but differs in having smaller perithecia and spores, with bristles that are white in the entire upper half.

However, it can be differentiated by its distinct algal arrangement, smaller perithecia with purely black bristles forming a horizontal, shiny crown, and slightly narrower spores.

These subtle but consistent differences in morphological features, particularly in the structure of perithecia and the characteristics of spores, are crucial for accurate identification and classification within the genus Trichothelium.

[1] As of its initial description, Trichothelium subargenteum had only been found in one location: near the village of Nuevos Reyes in the Beni Department of Bolivia (José Ballivián Province).