A new marine intracellular parasite Euduboscquella n. sp. (Dinoflagellata, Syndinea) infecting the planktonic ciliate Schmidingerella arcuata

Abstract

The syndinean dinoflagellate Euduboscquella n. sp., an intracellular parasite of the tintinnid ciliate Schmidingerella arcuata was discovered from Korean coastal water and described based on morphology and nuclear 18S ribosomal gene sequences. Euduboscquella n. sp. shared its development process of trophnot with congeners, but differed from these species by (1) shield of the trophont with 25&#8211 40 grooves converging toward the center of the shield (2) persistence of grooves during extracellular development (3) single food vacuole during sporogenesis and (4) dinospores ca. 14 &micro m in size. After sporogenesis, Euduboscquella n. sp. produced four different types of spore morphology that showed completely identical 18S nucleotides sequences. In addition, the 18S sequences were completely identical with the previously reported population of Euduboscquella sp. ex Schmidingerella arcuata from Assawoman Bay, USA. It is assumed that the two populations are likely conspecific. When Euduboscquella n. sp. was detected, Favella ehrenbergii, a widely recorded tintinnid co-occurred with the host Schmidingerella arcuata. However, the parasite failed to shift to the alternative host, F. ehrenbergii, during a cross-infection experiment.es. Euduboscquella n. sp. shared its development process of trophnot with congeners, but differed from these species by (1) shield of the trophont with 25&#8211 40 grooves converging toward the center of the shield (2) persistence of grooves during extracellular development (3) single food vacuole during sporogenesis and (4) dinospores ca. 14 &micro m in size. After sporogenesis, Euduboscquella n. sp. produced four different types of spore morphology that showed completely identical 18S nucleotides sequences. In addition, the 18S sequences were completely identical with the previously reported population of Euduboscquella sp. ex Schmidingerella arcuata from Assawoman Bay, USA. It is assumed that the two populations are likely conspecific. When Euduboscquella n. sp. was detected, Favella ehrenbergii, a widely recorded tintinnid co-occurred with the host Schmidingerella arcuata. However, the parasite failed to shift to the alternative host, F. ehrenbergii, during a cross-infection experiment.