Drechslerosporium cornellii gen. et sp. nov. within the Basidiobolaceae exhibiting unique conidial discharge and digitate chlamydospores

We describe Drechslerosporium cornellii gen. et sp. nov., a phylogenetically distinct fungal genus isolated from decaying plant litter at Cornell Plantations, Ithaca, New York, USA. This novel monotypic genus is assigned to the family Basidiobolaceae and is characterized by two unique morpho-developmental traits: (1) retention of prominent conidiophore appendages on discharged conidia following circumscissile rupture of the apical swelling and (2) direct ontogeny of digitate chlamydospores from primary conidia, a trait unrecorded in related genera.

Multilocus phylogenetic analysis of nuclear ribosomal 28 S, ITS, and RPB 2 sequences robustly resolves Drechslerosporium as a sister lineage to Basidiobolus within Basidiobolaceae, yet forming a distinct evolutionary clade. This phylogenetic placement, coupled with its unique morphological characteristics, necessitates formal recognition of Drechslerosporium as an independent genus. Accordingly, a revised taxonomic circumscription of the Basidiobolaceae is provided to accommodate the newly discovered phenotypic and phylogenetic diversity.

These findings clarify specialized discharge mechanisms driving spore dispersal evolution and expand our understanding of structural diversification within early-diverging lineages of fungi.