Four new species of Resupinatus (Agaricales, Basidiomycota) on coniferous trees in Northeast China

Resupinatus species are widely distributed worldwide and are characterized by pleurotoid, cupulate-lamellate, cyphelloid, poroid, and merulioid basidiomata forms. Although numerous species have been described from subtropical to tropical regions in recent years, the species diversity of Resupinatus in temperate-boreal coniferous forests remains poorly investigated. In this study, four new species are described on the basis of morphological observations and molecular phylogenetic analyses.

Resupinatus angulatus is characterized by angular isolated pores, fusiform cystidioles, and curved cylindrical to allantoid basidiospores, and it occurs on fallen branches of Larix olgensis and Pinus koraiensis. Resupinatus latemarginatus is distinguished by circular to subcircular isolated pores, a wide sterile margin, fusiform cystidioles, ellipsoid basidiospores, and growth on fallen branches of Abies nephrolepis and P. koraiensis.

Resupinatus sinoapplicatus is characterized by sessile basidiomata with a lamellate hymenophore, globose basidiospores, and growth on fallen branches of P. koraiensis. Resupinatus sinuosus is recognized by its sinuous to irregular isolated pores, fusiform cystidioles, and ellipsoid basidiospores, and it occurs on rotten wood of A. nephrolepis. This study expands knowledge of wood-decaying fungal diversity associated with temperate-boreal coniferous trees and highlights that fungal species diversity in this region remains insufficiently explored, warranting further investigation.