Morphological and Multigene Phylogenetic Evidence Supports Thyronectria pseudocaudata sp. nov., a New Species From Iran

A microfungal specimen collected from the dead branches of Berberis integerrima in North Khorasan Province, Iran, was investigated using morphological and multilocus phylogenetic approaches. Phylogenetic analyses based on combined ITS, LSU, ACT1 , TEF1 , and TUB2 sequence data, employing maximum likelihood and Bayesian Inference methods, supported the placement of the fungus within Thyronectria and revealed it as a previously undescribed species. Thyronectria pseudocaudata sp. nov. is distinguished by blackish perithecial ascomata arising from a bark‐erumpent stroma, unitunicate cylindrical to clavate asci, and eight oblong to clavate, muriform, hyaline ascospores with 5–14 transverse septa and a single longitudinal or oblique septum. The ascospores produce suballantoid ascoconidia by budding within the asci, and a pycnidial asexual morph is formed in culture. Detailed morphological descriptions, illustrations, and a multilocus phylogenetic tree inferred from combined ITS–LSU– ACT1 – TEF1 – TUB2 sequence data are presented to substantiate the taxonomic novelty and phylogenetic position of T. pseudocaudata .