Bolbea parasitica A.T. Buaya & Thines, sp. nov.
MycoBank number: MB 833723; Index Fungorum number: IF 833723; Facesoffungi number: FoF; Figs 1–2.
Etymology: Named for its parasitic behaviour in ostracods.
Description: Thallus holocarpic in ostracods, killing the host while growing, finally consuming it entirely; hyphae regular, but cytoplasm fragmentation observable in older hyphae or upon contact with water, with infrequent constrictions, usually 5–15 µm broad on modified MEA, with their cytoplasmic contents maturing into zoospores; zoospores roundish within hyphae, about 6 µm diam, diplanetic with secondary zoospores being more elongate in shape and forming after a rest period, without pronounced cyst development; zoospore discharge from mature hyphae by the dissolution of hyphal apices and the formation of short discharge tubes; growth on modified MEA of intermediate density with contorted hyphae, slowing down growth after several days; upon contact with water producing zoospores; resting spores and oospores not observed.
Typus: Germany, Hessen, Frankfurt am Main, Rebstocksee, July 2018, A.T. Buaya (holotype FR-0046116, ex-type partial nrSSU sequence MN688695).
Fig. 1. Morphology and asexual cycle of the parasitoid. A Open carapace of the host containing an almost mature parasitoid thallus. B. Mature parasite thallus. C. Detail of an older, mature hyphal branch with some fragmentation of the cytoplasm. D. Zoospores differentiation. E. Just-differentiated zoospores inside a hyphal branch. F. Empty hyphae with discharge tubes.
Fig. 2. Cultural characteristics and fulfilment of Koch’s postulates. A. Top view of a culture plate. B. Bottom view of the same plate. C. Close-up of the colony margin with contorted hyphae. D. Re-inoculation to living individuals of a clonal ostracod culture for fulfilling Koch’s postulates. E. Sacrificed individuals with abundant zoospores attached to the host carapace.