Dinema platysomum (Skuja 1939) Lee et Patterson 2000

Aydin, Esra Elif & Lee, Won Je, 2012, Free-living Heterotrophic Flagellates from Intertidal Sediments of Saros Bay, Aegean Sea (Turkey), Acta Protozoologica 51 (2), pp. 119-137 : 125

Dinema platysomum (Skuja 1939) Lee et Patterson 2000 ( Figs 1o , 2n )

(= Anisonema platysomum Skuja 1939 )

Observation: Cell is elliptical, about 24 μm long, flattened and flexible with a chisel-shaped ingestion apparatus and pellicular striations on ventral and dorsal faces of the cell. The ventral striations are more distinct than the dorsal ones. The two flagella are of unequal length. The anterior flagellum is slightly thickened, is about 1.5 times the cell length and sweeps from side to side. The posterior flagellum is thicker, is most strongly developed proximally, is about 2.8 times the cell length and trails. The flagellar pocket is located in the left side of the cell and the nucleus is located in the right. The cell moves by gliding and may jerk to change the direction. One cell observed.

Remarks: This species had been described under the name of Anisonema platysomum Skuja 1939 , but was transferred to Dinema by Lee and Patterson (2000) because it is metabolic, and has an ingestion apparatus and thick pellicle. Dinema inaequale Larsen et Patterson 1990 is a junior synonym of D. platysomum ( Lee and Patterson 2000) . Our observation is in agreement with the observations of Larsen and Patterson (1990) and Lee and Patterson (2000). Dinema platysomum resembles some species of the genus Anisonema like A. acinus and A. glaciale in genaral appearence, but can be distinguished by the flexible body which is the most reliable character for distinguishing Anisonema and Dinema . It was found in marine sites in tropical Australia and Fiji and the cell length was reported to be 20 to 30 µm ( Larsen and Patterson 1990, Ekebom et al. 1996, Lee and Patterson 2000, Lee 2001).

Figures

Fig. 1. a – Actinomonas mirabilis/Pteridomonas danica; b – Amastigomonas mutabilis; c – Ancyromonas micra; d – Bicosoeca conica; e – Bordnamonas tropicana; f – Caecitellus parvulus; g – Cafeteria minuta; h – Cafeteria roenbergensis; i – Cyranomonas australis; j – Developayella elegans; k – Discocelis saleuta; l – Goniomonas amphinema; m – Goniomonas pasifica; n – Kiitoksia ystava; o – Dinema platysomum; p – Anisonema acinus; q – Heteronema exaratum; r – Heteronema ovale; s – Kathablepharis remigera; t – Notosolenus canellatus; u – Massisteria marina; v – Metromonas grandis; w – Neobodo designis; x – Neobodo saliens; y – Percolomonas similis. Scale bar: 10 μm for all figures.

Fig. 2. a – Actinomonas mirabilis/Pteridomonas danica; b – Amastigomonas mutabilis; c – Ancyromonas micra; d – Bicosoeca conica; e – Caecitellus parvulus, note the mouth on the left-hand side; f – Bordnamonas tropicana; g – Cafeteria roenbergensis; h – Cyranomonas australis; i – Developayella elegans; j – Discocelis saleuta; k – Goniomonas amphinema; l – Cafeteria minuta, feeding cell; m – Anisonema acinus, dorsal view, note the ingestion organelle; n – Dinema platysomum, ventral view showing surface striations; o – Goniomonas pacifica; p – Heteronema exaratum, ventral view, general appearance of cell; q – Kathablepharis remigera; r – Massisteria marina; s – Neobodo saliens; t – Neobodo designis; u–v – Heteronema ovale, same cell; u – general appearance; v – extended cell. All micrographs are DIC images. Scale bar: 5 μm for all figures.