Phylogenetic evidence reveal a close relationship between Amphichorda and Ovicillium in Bionectriaceae (Hypocreales).

Abstract

Animal excrement serves as the primary substrate for Amphichorda, which is found in a wide range of habitats. Based on evolutionary relationships, the genus is currently classified within the Bionectriaceae. However, the phylogenetic position of Amphichorda and its associated taxa remains unresolved due to limited sampling in previous studies. Here, we discovered and identified five Amphichorda species, significantly advancing our understanding of this genus. Using six genomic loci (ITS, nrSSU, nrLSU, tef1α, rpb1, and rpb2) to expand taxonomic sampling, we reconstructed a phylogenetic framework for the Bionectriaceae, with a focus on Amphichorda and related taxa. Phylogenetic analyses revealed a close genetic connection between Amphichorda and related genera, yet they formed distinct clades within the Bionectriaceae and were clearly differentiated. The extensive sampling demonstrated stable phylogenetic relationships among Amphichorda, Hapsidospora, Ovicillium, Proxiovicillium, and Bulbithecium. Furthermore, we described two new species, A.guizhouensis sp. nov. and O.pseudoattenuatum sp. nov., supported by DNA data and morphological characteristics. A comprehensive comparison of morphological traits across all members of Amphichorda and Ovicillium was conducted. This study clarifies taxonomic boundaries and evolutionary relationships within the two genera and contributes to the overall understanding of the biodiversity and systematics of the Bionectriaceae.