Recent occurrence of Ripartites metrodii in Scotland

DNA barcoding, phylogenetic reconstruction and implications for conservation

Abstract

Ripartites metrodii, a saprotrophic basidiomycete, has seldom been recorded in Britain (two records currently available on the Global Biodiversity Information Facility (GBIF), both from England, and none on the NBN Atlas database). The 2005 Checklist of the British & Irish Basidiomycota (CBIB) recognised only a single Ripartites species, R. tricholoma, following a widely held view that this was a ‘very polymorphic’ species. R. metrodii was cited only as one of several synonyms variously recognised at species level elsewhere in Europe. The FRDBI database currently follows CBIB. There have been five previous Scottish collections reported as R. tricholoma, but none of these appear to correspond to R. metrodii as now understood.

Here we report on the recent occurrence of R. metrodii in a coniferous forest in the Scottish Highlands, present its barcoding sequence, and discuss the implications for conservation of this species.  Morphological and molecular analyses, including DNA barcoding and phylogenetic reconstruction, confirmed the identity of the specimens. Our material fitted into a well supported cluster treated as R. metrodii in the UNITE database and distinctly separate from a cluster treated as R. tricholoma. This supports the view that they should be treated as two different species, albeit with the names provisionally assigned until such time as sequences are obtained for type material. The findings also underscore the importance of mature conifer plantations, traditionally considered low in biodiversity, in supporting valuable fungal communities. These plantations, while often overlooked, contribute significantly to the conservation of ectomycorrhizal and saprotrophic fungi, highlighting the need for their inclusion in biodiversity management plans.