Cyst morphology of a chain‐forming unarmored dinoflagellate Gyrodinium impudicum Fraga et Bravo

Cysts of a chain‐forming dinoflagellate Gyrodinium impudicum Fraga et Bravo (Gymnodiniales) were found in surface sediments of Harima‐Nada and Nakaumi, western Japan. The detailed morphology of living and empty cysts is described. The living cysts are roundish to ellipsoidal in polar view, and hemispherical in lateral view. Among three empty cysts obtained, two different archeopyles were observed; either a long slit with an operculum, or a hole with irregular zigzag outline. The living cysts of Gyro. impudicum are morphologically similar to those of the genus Chattonella antiqua (Hada) Ono and Chattonella marina (Subrahmanyan) Y. Hara et Chihara (Raphidophyceae), except cyst color and contents. The living cysts of Gyro. impudicum were rarely encountered, and their density was always less than 1 cell in 1 cm−3 in the present samples.

[1]  G. Hallegraeff,et al.  Gymnodinium microreticulatum sp. nov. (Dinophyceae): a naked, microreticulate cyst-producing dinoflagellate, distinct from Gymnodinium catenatum and Gymnodinium nolleri , 1999 .

[2]  M. Ellegaard,et al.  Fine structure of the flagellar apparatus and morphological details of Gymnodinium nolleri sp. nov. (Dinophyceae), an unarmored dinoflagellate producing a microreticulate cyst , 1999 .

[3]  J. Sonneman,et al.  A Taxonomic Survey of Cyst-producing Dinoflagellates from Recent Sediments of Victorian Coastal Waters, Australia , 1997 .

[4]  S. Fraga,et al.  Gyrodinium impudicum sp. nov. (Dinophyceae), a non toxic, chain-forming, red tide dinoflagellate , 1995 .

[5]  Y. Fukuyo,et al.  Geographical Distribution of the Toxic Dinoflagellate Gymnodinium catenatum Graham in Japanese Coastal Waters , 1994 .

[6]  Satoru Kobayashi,et al.  Motile cell-like cyst of Gyrodinium instriatum Freudenthal et Lee (Dinophyeeae) , 1992 .

[7]  G. Hallegraeff,et al.  The resting cyst of the red-tide dinoflagellate Alexandrium minutum (Dinophyceae) , 1991 .

[8]  G. Hallegraeff,et al.  Dinoflagellate Cysts in Recent Marine Sediments from Tasmania, Australia , 1990 .

[9]  D. Anderson,et al.  THE UNIQUE, MICRORETICULATE CYST OF THE NAKED DINOFLAGELLATE GYMNODINIUM CATENATUM 1 , 1988 .

[10]  Y. Fukuyo,et al.  Cyst and motile morphology of a colonial dinoflagellate Pheopolykrikos hartmannii (Zinunermann) comb. nov. , 1986 .

[11]  K. Matsuoka.  Archeopyle structure in modern gymnodinialean dinoflagellate cysts , 1985 .

[12]  D. Anderson,et al.  SEXUAL PROCESSES IN THE LIFE CYCLE OF GYRODINIUM UNCATENUM (DINOPHYCEAE): A MORPHOGENETIC OVERVIEW 1 , 1984 .

[13]  G. Morey-Gaines,et al.  Encystment and reproduction of the predatory dinoflagellate, Polykrikos kofoidi Chatton (Gymnodiniales)* , 1980 .

[14]  H. Iwasaki,et al.  Studies on the Red Tide Dinoflagellates-II , 1969 .

[15]  B. Dale,et al.  Modern dinoflagellate cysts and evolution of the Peridiniales , 1968 .

[16]  H. Iwasaki.  THE LIFE-CYCLE OF PORPHYRA TENERA IN VITRO , 1961 .