Morphology and molecular phylogeny of Euduboscquella n. sp. (Dinoflagellata, Syndinea), an endoparasite of the ciliate Schmidingerella arcuata

Abstract

The syndinean dinoflagellate Euduboscquella n. sp., an intracellular parasite ofthe planktonic ciliate Schmidingerella arcuata was discovered from Koreancoastal water and described based on morphology and nuclear 18S ribosomalgene sequences. The intracellular development process of Euduboscquella n. sp.was consistent with its congeners, but differed from closely related species by(1) shield of the trophont with 25&#8211 40 grooves converging toward the center ofthe shield (2) persistence of grooves during extracellular development (3)single food vacuole during sporogenesis and (4) dinospores ca. 14 μm in size.After sporogenesis, Euduboscquella n. sp. produced 4 morphologically distinctspore types that showed completely identical 18S nucleotides sequences. Inaddition, the 18S sequences were completely identical with the previouslyreported population of Euduboscquella sp. ex Schmidingerella arcuata fromAssawoman Bay, USA. It is assumed that the two populations are likelyconspecific. When Euduboscquella. n. sp. was detected, Favella ehrenbergii, awidely recorded planktonic ciliate species co-occurred with the hostSchmidingerella arcuata. However, the parasite failed to shift to the alternativehost, F. ehrenbergii, during a cross-infection experiment.uences. The intracellular development process of Euduboscquella n. sp.was consistent with its congeners, but differed from closely related species by(1) shield of the trophont with 25&#8211 40 grooves converging toward the center ofthe shield (2) persistence of grooves during extracellular development (3)single food vacuole during sporogenesis and (4) dinospores ca. 14 μm in size.After sporogenesis, Euduboscquella n. sp. produced 4 morphologically distinctspore types that showed completely identical 18S nucleotides sequences. Inaddition, the 18S sequences were completely identical with the previouslyreported population of Euduboscquella sp. ex Schmidingerella arcuata fromAssawoman Bay, USA. It is assumed that the two populations are likelyconspecific. When Euduboscquella. n. sp. was detected, Favella ehrenbergii, awidely recorded planktonic ciliate species co-occurred with the hostSchmidingerella arcuata. However, the parasite failed to shift to the alternativehost, F. ehrenbergii, during a cross-infection experiment.