Chiodecton xanthonosorediatum is a species of corticolous (bark-dwelling), crustose lichen in the family Roccellaceae.

The type specimen was collected by the author from Serra da Bodoquena (Mato Grosso do Sul) at an altitude of 460 m (1,510 ft).

The lichen has a crustose, granular thallus with a pale greenish-white hue and an uneven, dull surface.

Thin-layer chromatography analysis detects the presence of lichexanthone, a lichen product found in the cortex.

Chiodecton xanthonosorediatum shares similarities with C. complexum, particularly in the structure of the soralia, but its distinguishing feature is the presence of lichexanthone.