Molecular or morphological species? Myxomycete diversity in a deciduous forest in northeastern Germany
Feng, Yun; Schnittler, Martin
To compare morphological and molecular diversity for lignicolous myxomycetes, DNA samples of all specimens found within a survey covering the late-autumn aspect of myxomycete fructifications on coarse woody debris were sequenced, using partial sequences of the nuclear smallsubunit ribosomal RNA gene (SSU) as a barcode marker. A total of 161 logs, mostly from European beech (Fagus sylvatica) in the old-growth forest of Eldena in northeastern Germany, was surveyed from early October to early December 2012, resulting in 530 collections representing 27 morphospecies (26 species and one variety) from 14 genera. Bright-spored taxa were far more abundant (508 records /17 taxa/50 ribotypes) than dark-spored ones (22 records/10 taxa/15 ribotypes). Accumulation curves constructed from morphospecies and ribotypes both converged, resulting in figures of 32.6 ± 4.9 / 90.0 ± 11.1 for taxon / ribotype diversity to be expected according to the Chao2 estimator. A phylogeny based on partial SSU sequences for bright-spored myxomycetes revealed morphospecies to be largely consistent with phylogenetic groups. Most but not all intensely sampled morphospecies contain multiple ribotypes that cannot be differentiated by light microscopy. The study demonstrates that SSU sequences can function as reliable barcode markers for myxomycetes, but these also reveal a significant, yet not infinite, amount of hidden diversity.