Expanding the Inventory of Seven Unrecorded Marine Penicillium with Morphological Descriptions and Phenotypic Variability.

Penicillium species are widely distributed across both terrestrial and marine environments. However, their morphological plasticity often complicates species-level identification, necessitating the use of multigene phylogenetic approaches. In this study, we investigated 11 Penicillium strains isolated from diverse marine substrates and deposited in the Marine Fungal Resource Bank (MFRB). These strains had previously shown ambiguous phylogenetic placements and were re-identified using an updated reference dataset. Through an integrative taxonomic approach combining multi-locus phylogenetic analyses (ITS, BenA, and CaM) with detailed morphological characterization, the strains were identified as seven species: P. aurantioviolaceum, P. fusisporum, P. yezoense, P. nudgee, P. taii, P. sajarovii, and P. neoherquei. All seven species are newly recorded from Korean marine environments. Furthermore, this study provides the first recommended morphological descriptions for several species that previously lacked valid diagnoses, facilitating future taxonomic comparisons and contributing to a more comprehensive understanding of marine Penicillium diversity.