First evidence of the deep-sea fungus Oceanitis scuticella Kohlmeyer (Halosphaeriaceae, Ascomycota) from the Northern Hemisphere
2016
Dupont, Joëlle | Schwabe, Enrico
We report on a collection of the deep-sea fungus Oceanitis scuticella from recently sunken wood at abyssal depth in the Northwest Pacific Ocean. The fungus was originally described as wood-associated from the Angola Basin. Subsequently, it was also found on sunken wood in the Southwest Pacific Ocean. Ascomata and ascospores of O. scuticella were examined by scanning electron microscopy and light microscopy. The phylogenetic affiliation of the fungus within the Halosphaeriaceae was demonstrated using partial nuclear internal transcribed spacer (ITS) regions and large subunit (LSU) rDNA sequencing. Slight morphological differences between this collection and previously described material were observed concerning ascomata shape, namely the drop-shaped cavity, the form of the hypostroma and the thickness of the peridium. In addition, the ascospores were smaller than those reported in previous collections. LSU rDNA phylogeny provided a good support for the placement of the NW Pacific Ocean sample within O. scuticella. The ITS rDNA sequence of the present collection differed from those of the earlier collections by 2.5–3%, a value accepted for intraspecific variation in fungi. Based on the present material, some factors interpreted as indicators for true deep-sea fungi, such as the absence of bark or co-existing xylophagic bivalves in sunken wood, are discussed and their importance is considered as limited.
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