Molecular data support rejection of the generic concept in the Coccotremataceae (Ascomycota)

Abstract

The Coccotremataceae is a small family including two genera: Coccotrema with a crustose, granulate to verrucose thallus and Lepolichen with terete lobes and rhizines. The generic concept based on this morphological difference was re-evaluated using three molecular markers, mt SSU rDNA, nu LSU rDNA, and the nu ITS region. The analysis of the ITS region does not provide sufficient resolution within the Coccotremataceae, while the other two data sets contradict the current generic concept. The mt SSU and nu LSU data sets and the combined analysis of the two data sets all place Lepolichen within Coccotrema. However, an alternative topology with monophyletic Coccotrema cannot be rejected when the ITS data set is included in the combined analyses. This shortcoming of the ITS data set can be overcome by the combined analysis of all three data sets, where monophyletic Coccotrema can be rejected using parametric bootstrapping, as in the mt SSU and nu LSU data sets and combination thereof. It is proposed to reduce Lepolichen into synonymy with Coccotrema. The correct name for the only species previously placed in Lepolichen is Coccotrema coccophontm (Mont.) I. Schmitt, Messuti & Lumbsch.