Caecitellus parvulus ( Griessmann 1913 ) Patterson et al. 1993

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 : 124

Caecitellus parvulus ( Griessmann 1913) Patterson et al. 1993 ( Figs 1f , 2e )

(= Bodo parvulus Griessmann 1913 )

Observation: Cell is about 3 μm long and somewhat triangular or rounded. There is a mouth protruding on the left ventral side of the cell. The cell has two flagella of unequal length. The acronematic anterior flagellum beats slowly and inserts apically. It is slightly longer than the cell length. The non-acronematic posterior flagellum is about 2.5 times the cell length, emerges from the ventral face of the cell and trails posteriorly. The cell glides slowly with the anterior flagellum in close contact with the substrate. One cell observed.

Remarks: The species was first assigned to Bodo parvulus Griessmann 1913 , but Patterson et al. (1993) revealed ultrastructural features which are not compatible with a bodonid flagellate and placed it in the new genus Caecitellus . O’Kelly and Nerad (1998) reconstructed the kinetid architecture of this species and found a high similarity with the Bicosoecida. But unlike Bicosoecida, Caecitellus lacks flagellar hairs and due to this Al-Qassab et al. (2002) placed this taxa under a new group named Hamatores with pseudodendromonads, which also does not have flagellar hairs and has similar ultrastructural characters to Caecitellus ( Al-Qassab et al. 2002) . Recently, Hausmann et al. (2006) made a molecular and ultrastructural study and added two new species into this genus: Caecitellus pseudoparvulus and Caecitellus paraparvulus . According to Hausmann et al. (2006), these species including C. parvulus are distinguished primarily by the number of microtubules in flagellar root 3 forming the cytoskeleton of the feeding basket ( C. parvulus : 24, C. pseudoparvulus : 35, C. paraparvulus : 29). The microtubule numbers determine the size of the feeding basket, but may not be a good character for identifying morphospecies under a light microscope. Thus, in this study, we prefer to follow the previous works ( Larsen and Patterson 1990, Lee and Patterson, 2000, Al-Qassab et al. 2002)’ criterion for this morphospecies. This species is one of the most commonly encountered heterotrophic flagellates worldwide ( Patterson and Lee 2000).

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.