Phycophthorum isakeiti B.T. Hassett, sp. nov.

MycoBank number: MB 837516; Index Fungorum number: IF 837516Facesoffungi number: FoF;

ZooBank: urn:lsid:zoobank.org:act:E4526C74-9FD2-4B30- A3BE-1898806851FE

Late disposita. Symbiotica diatomo marina Pleurosigmate. Zoospora, sporangia,et cellulavegetativa hyalina. Cellularumepibioticarumet endobioticarum. Reproductio endobiotica divisione binaria. Cellulae endobioticae vegetativae sphaeroes (II–X micrometrorum diametri) atque infrequenter indigestae. Reproductio epibiotica divisione binaria. Sporangium epibioticum habent zoospororum. Zoospora motila biflagellata aliquantum forma ellipsis (II micrometrorum diametri) atque subfusiformae aspectu laterali oblongaque microscopia electrorum perscrutantium. Zoospora fila longa habent quae migrationem.Cellulae motilia residet atque frustulum actionis cavae penetrat. Cellula bothrosomia, mitochondria cristis cavis, vacuolia, et complexus lipidos continet. Murus cellulae lamellarum concretus quae actionem cavam coniunctam creare possunt.

Widely distributed. Symbiotic with the marine diatom Pleurosigma. Zoospores, sporangia, and vegetative cells hyaline. Cells epibiotic and endobiotic. Epibiotic and endo- biotic reproduction by binary division. Vegetative cells spheroidal (2–10 lm diameter) and infrequently amorphic. Motile biflagellate zoospores slightly oval (2 lm diameter) and appear subfusiform in lateral view and oblong with scanning electron microscopy. Motile cell settles and penetrates frustule with tubular process. Cell contains bothrosomes, mitochondria with tubular cristae, vacuoles, and lipid inclusions. Cell wall comprised of lamellae that can form a contiguous tubular process.

Type material: The name-bearing type (hapanotype) is Smithsonian Institute, catalog number: USNM1613222; consisting of cells fixed and embedded in a transmission electron microscopy block.

Type host: Pleurosigma sp. diatoms

Etymology: Named in honor of the plant pathologist Dr. Thomas Isakeit.

Holotype locality: Tromsø, Norway (N69.632 E18.906)

Habitat: From nearshore marine sediment. Molecularly from northern Atlantic water, Arctic Ocean sea ice, and Arctic Ocean seawater

NCBI Accession: MN382127