Phylogeny

An early (2002) phylogenetics study showed that the order Ostropales, as was then circumscribed, was paraphyletic, and proposed that the Ostropales sensu lato included the Gyalectales and Trapeliaceae.^[3] Although they had traditionally been considered to be only distantly related, molecular studies suggested a much closer phylogenetic relationship.^[4][5] As a result, of the molecular data, Kauff and Lutzoni subsumed the Gyalectales into the Ostropales, as the latter name was published earlier (1932 vs. 1986).^[3]

In 2018, Kraichak and colleagues used a recently developed "temporal phylogenetic" approach to identify temporal bands for specific taxonomic ranks. Based on this approach, clades that share a common ancestor between 176 and 194 Mya and a time window of 111–135 Mya correspond to order-level and family-level, respectively. The Gyalectales clade, consisting of the families Trichotheliaceae, Coenogoniaceae, Sagiolechiaceae, Gyalectaceae and Phlyctidaceae, has a crown node that falls within the temporal band for orders. For this reason the name Gyalectales was resurrected to represent the monophyletic clade.^[6] Gyalectales itself is placed in Ostropomycetidae, one of two major subclasses in the Lecanoromycetes.

This proposed classification has been accepted in a later review of the temporal banding method for fungus systematics,^[7] as well a 2020 update on ascomycete classification.^[8]