Arthrobotrys is the most complex genus of Orbiliaceae nematode-trapping fungi. Its members are widely distributed in various habitats worldwide due to their unique nematode-trapping survival strategies. During a survey of nematophagous fungi in Yunnan Province, China, twelve taxa were isolated from terrestrial soil and freshwater sediment habitats and were identified as six new species in Arthrobotrys based on evidence from morphological and multigene (ITS, TEF, and RPB2) phylogenetic analyses. These new species i.e., Arthrobotrys eryuanensis, A. jinpingensis, A. lanpingensis, A. luquanensis, A. shuifuensis, and A. zhaoyangensis are named in recognition of their places of origin. Morphological descriptions, illustrations, taxonomic notes, and a multilocus phylogenetic analysis are provided for all new taxa. In addition, a key to known species in Arthrobotrys is provided, and the inadequacies in the taxonomic study of nematode-trapping fungi are also discussed.

Nematode-trapping fungi are widely studied due to their unique morphological structure, survival strategy, and potential value in the biological control of harmful nematodes. During the identification of carnivorous fungi preserved in our laboratory, five novel nematode-trapping fungi were established and placed in the genera Arthrobotrys and Drehslerella based on morphological and multigene (ITS, TEF, and RPB2) phylogenetic analyses. A. hengjiangensis sp. nov. and A. weixiensis sp. nov. are characterized by producing adhesive networks to catch nematodes. Dr. pengdangensis sp. nov., Dr. tianchiensis sp. nov., and Dr. yunlongensis sp. nov. are characterized by producing constricting rings. Morphological descriptions, illustrations, taxonomic notes, and phylogenetic analysis are provided for all new taxa; a key for Drechslerella species is listed; and some deficiencies in the taxonomy and evolution study of nematode-trapping fungi are also discussed herein.

Arthrobotrys jindingensis and A. tongdianensis, two new species isolated from the freshwater sediment and terrestrial soil in Lanping county, Yunnan, China, are introduced based on morphology and multi-locus phylogenetic analysis (ITS, TEF and RPB2). A. jindingensis is characterized by its branched conidiophores with irregularly swollen nodular apex, pyriform or obovoid, and 1-septate conidia. A. tongdianensis is characterized by its branched conidiophores, and ellipsoid or obovate, 1-septate conidia. Phylogenetic analysis supports them as two new species within Arthrobotrys with high support. The descriptions and illustrations of these two species are provided in this paper.

During the investigation of nematode-trapping fungi in Yunnan Province, four strains were isolated from the soil collected in Nujiang City, Yunnan Province, China and were identified as two new Arthrobotrys (Orbiliaceae) species based on morphology and multigene (ITS, EF1-α, and RPB2) phylogenetic analysis. Arthrobotrys gongshanensis is characterized by conidiophores producing 1–5 short denticles near the apex, bearing a single conidium on each denticle and obovoid to fusiform, 1–4-septate conidia. Arthrobotrys luzhangensis is characteristics by its obovoid to fusiform, 1–4-septate macroconidia, and clavate or obovoid, aseptate microconidia. These two new species both capture nematodes using adhesive networks. The multigene phylogenetic analyses further confirmed the taxonomic positions of these two new species within Arthrobotrys. This paper described them with illustrations and compared them with similar taxa.

The evolution of carnivorous fungi in deep time is still poorly understood as their fossil record is scarce. The approximately 100-million-year-old Cretaceous Palaeoanellus dimorphus is the earliest fossil of carnivorous fungi ever discovered. However, its accuracy and ancestral position has been widely questioned because no similar species have been found in modern ecosystems. During a survey of carnivorous fungi in Yunnan, China, two fungal isolates strongly morphologically resembling P. dimorphus were discovered and identified as a new species of Arthrobotrys (Orbiliaceae, Orbiliomycetes), a modern genus of carnivorous fungi. Phylogenetically, Arthrobotrys blastospora sp. nov. forms a sister lineage to A. oligospora. A. blastospora catches nematodes with adhesive networks and produces yeast-like blastospores. This character combination is absent in all other previously known modern carnivorous fungi but is strikingly similar to the Cretaceous P. dimorphus. In this paper, we describe A. blastospora in detail and discuss its relationship to P. dimorphus.

The diversity of nematode-trapping fungi (NTF) holds significant theoretical and practical implications in the study of adaptive evolution and the bio-control of harmful nematodes. However, compared to terrestrial ecosystems, research on aquatic NTF is still in its early stages. During a survey of NTF in six watersheds in Yunnan Province, China, we isolated 10 taxa from freshwater sediment. Subsequent identification based on morphological and multigene (ITS, TEF1-α, and RPB2) phylogenetic analyses inferred they belong to five new species within Arthrobotrys. This paper provides a detailed description of these five novel species (Arthrobotrys cibiensis, A. heihuiensis, A. jinshaensis, A. yangbiensis, and A. yangjiangensis), contributing novel insights for further research into the diversity of NTF and providing new material for the biological control of aquatic harmful nematodes. Additionally, future research directions concerning aquatic NTF are also discussed.