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.

Background: Understanding the patterns of species richness across elevational gradients is a key concept for contemporary research in ecology and evolution, and critical to understanding large-scale trends in biodiversity, global change and conservation. However, patterns of elevational species richness between taxonomic groups, regions and latitudes are inconsistent, so that various, sometimes conflicting hypotheses exist. Several scholars have pointed out that research on elevational distribution patterns is often biased by the sampling design employed. To test this hypothesis, we analyzed species richness of Nematode-Trapping Fungi (NTF) across an elevation gradient at two mountainous sites in western Yunnan Province, P.R. China. We tested for potential differences in the results when using different sampling designs.Results: A total of 3 genera, 17 species, 222 strains of NTF were isolated and identified from Gaoligongshan and Cangshan. Species accumulation curves for both sites and sampling modes had acceptable leveling, demonstrating sufficient sampling effort. At Gaoligongshan, the elevation distribution patterns of NTF were different under two sampling patterns. When reducing the analyzed altitude range in Gaoligongshan, the elevation distribution pattern of the NTF changed. A similar elevation distribution pattern was observed in Cangshan when testing the same altitude range. In general, when treating the same dataset using different sampling designs, the resulting distribution patterns of species richness and occurrence frequencies were clearly different. Moreover, after removal of the samples located within lower-altitude zones affected by anthropogenic interferences, the distribution pattern of NTF in the two sites tended to become uniform.Conclusion: The sampling design, and in particular the elevation interval between plots, has a significant effect on the assessment of species distribution in mountainous regions. Other factors such as human activities and the multi-dimensionality of biodiversity also contribute to result biases. It is recommended that sampling design is given careful consideration in future studies on the elevational gradients of species richness, using stratified approaches according to the most relevant factors.

Soil microbes’ response to sudden environmental changes is very complicated and has been lively debated. There are a handful of questions yet to answer: are there any succession rules for different soil microbial species to fit in the suddenly changed environment? And what is the correlation between the community succession and the habitat recovery? These questions remain unanswered yet. Nematode-trapping fungi (NTF) play a very important role in the soil ecosystem and can be studied by traditional culture method easily. So, in this study, the NTF community in two burned sites at two depths (0–10 and 10–20 cm) was investigated in comparison with adjacent unburned sites. While the original NTF community structure was rather different in the two unburned sites, the NTF community presented a consistent pattern in the two burned sites: (1) considerable amount of NTF in the shallow soil (0–10 cm) was killed by the extremely high temperature of fire and the vacant niches were subsequently replaced with NTF communities that were originally distributed in the deep soil (10–20 cm); (2) dominant species in the community changed from Arthrobotrys fungi which showed stronger saprophytic ability to Dactylellina fungi which showed stronger capturing ability; and (3) the vacant niche caused by the movement of Dactylellina fungi was taken by Drechslerella fungi. The study shows that microbes inhabited in the deep soil played a critical role in the after-fire process to recovery of the soil ecological system.

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.