The species diversity of early-diverging fungi has long lagged behind that of higher fungi, posing a significant obstacle to our comprehensive understanding of the fungal kingdom. Our ongoing research endeavors aim to address this gap by exploring the species diversity of early-diverging fungi in China. In this study, we describe three novel species within the Backusella, namely B. ellipticasp. nov., B. fujianensissp. nov., and B. variisporasp. nov., based on phylogenetic and morphological analyses. In the phylogenetic analysis of the ITS (internal transcribed spacer), LSU (large subunit of ribosomal RNA gene), and RPB1 (RNA polymerase II largest subunit gene) regions, the B. elliptica and B. fujianensis cluster closely with B. gigacellularis, B. ovalispora, and B. solicola, and the B. variispora is closely related to B. locustae and B. pernambucensis. Morphologically, B. elliptica is distinguished by elliptical sporangiospores, as well as cylindrical and hemispherical columellae. The B. fujianensis is characterized by elliptical sporangiospores, and various types of columellae such as hemispherical, subglobose, depressed globose and conical. The B. variispora is characterized by subglobose to globose sporangiospores, as well as hemispherical, subglobose to globose columellae. Additionally, the sporangiophores are long and monopodially branched in B. elliptica and B. fujianensis, while short and simple or sympodially branched in B. variispora. Physiologically, the maximum growth temperatures of B. elliptica (32 °C), B. fujianensis (35 °C), and B. variispora were (35 °C) were determined. With the inclusion of these newly described taxa, the total number of Backusella species known from China now stands at 12. Finally, we provide a key to facilitate the morphological identification of Backusella species from Asia.

Fungi of the Conidiobolus group belong to the family Ancylistaceae (Entomophthorales, Entomophthoromycotina, Zoopagomycota) and include over 70 predominantly saprotrophic species in four similar and closely related genera, that were separated phylogenetically recently. Entomopathogenic fungi of the genus Batkoa are very close morphologically to the Conidiobolus species. Their thalli share similar morphology, and they produce ballistic conidia like closely related entomopathogenic Entomophthoraceae. Ballistic conidia are traditionally considered as an efficient tool in the pathogenic process and an important adaptation to the parasitic lifestyle. Our study aims to reconstruct the phylogeny of this fungal group using molecular and genomic data, ancestral lifestyle and morphological features of the conidiobolus-like group and the direction of their evolution. Based on phylogenetic analysis, some species previously in the family Conidiobolaceae are placed in the new families Capillidiaceae and Neoconidiobolaceae, which each include one genus, and the Conidiobolaceae now includes three genera. Intermediate between the conidiobolus-like groups and Entomophthoraceae, species in the distinct Batkoa clade now belong in the family Batkoaceae. Parasitism evolved several times in the Conidiobolus group and Ancestral State Reconstruction suggests that the evolution of ballistic conidia preceded the evolution of the parasitic lifestyle.

Absidia is widely distributed in soil, koji, and various types of feces. A multi-locus phylogeny covering the small subunit (SSU), internal transcribed spacer (ITS), and large subunit of ribosomal RNA gene (LSU rDNA), translation elongation factor 1-alpha (TEF1α), and actin (Act), combined with morphological characteristics, revealed five new species in this genus. This study provides their descriptions and illustrations and discusses their differences from morphological allies and phylogenetic relatives. Absidia collariatasp. nov. is distinguished from other species in terms of the length of collars. A. hainanensissp. nov. is named after the geographical location Hainan, distinctive with a higher maximum growing temperature. A. pyriformissp. nov. is different from other species in terms of sporangial shape. A. tardivasp. nov. is characterized by slow growth. And A. tibetensissp. nov. is named after the geographical location Tibet and differentiated by more ampulliform swellings. This study further enriches the species diversity of Absidia as the latest discovery of early-diverging fungi in China.

The genus Conidiobolus s.s. (Conidiobolaceae, Entomophthorales) has been delimited to accommodate members that produce microspores. Herein, morphological studies, combined with phylogenetic analysis based on the nuclear large subunit of rDNA (nucLSU), the mitochondrial small subunit of rDNA (mtSSU), and the elongation-factor-like gene (EFL) revealed two Conidiobolus s.s. species isolated from plant debris in China. Conidiobolus longiconidiophorus sp. nov. is mainly characterised by its long primary conidiophores, while Conidiobolus polysporus sp. nov. is diagnosed by 2–3 primary conidia arising from branched primary conidiophores. Phylogenetically, the former is grouped into a separate clade, while the latter is closely related to C. incongruus, but is morphologically distinguished by its larger primary conidia and branched conidiophores.

Neoconidiobolus pseudothromboides is proposed as a species new on the basis of morphological characteristics, physiological feature and molecular phylogeny. This new species is morphologically allied to N. thromboides. However, the maximum growth temperature of this new species is lower than that of N. thromboides and it grows slower than N. thromboides. The phylogenetic analysis of mitochondrial small subunit (mtSSU), nuclear large subunit (nucLSU) and translation elongation-factor-like (EFL) reveals that Neoconidiobolus is divided into three clades, and N. pseudothromboides sp. nov. is closely related to N. lachnodes rather than N. thromboides. Morphological comparisons between N. pseudothromboides sp. nov. and its affinities are provided herein.