Acantholichen galapagoensis, commonly known as the Galapagos spiny gladiator lichen,[1] is a species of basidiolichen in the family Hygrophoraceae.

Found in the Galápagos Islands, it was formally described as a new species in 2016 by Manuela Dal-Forno, Frank Bungartz, and Robert Lücking.

The type specimen was collected in Isla Santa Cruz at an elevation of 684 m (2,244 ft).

Here in a dense forest of Cinchona pubescens it was found growing over Frullania liverworts.

[2] In 2017, Acantholichen galapagoensis was assessed for the global IUCN Red List as vulnerable due to its fragmented population, and because population control of the invasive Cinchona trees has a direct, detrimental impact on the lichen populations associated with it.