Cercomonas granulatus Lee and Patterson, 2000

Lee, Won Je & Patterson, David J., 2000, Heterotrophic flagellates (Protista) from marine sediments of Botany Bay, Australia, Journal of Natural History 34, pp. 483-562 : 541-542

Cercomonas granulatus Lee and Patterson , n. sp. (fi gures 21l -n, 22c -d. Type micrographs: fi gure 21l -m)

Diagnosis. Cercomonas , cell pyriform, 7-15 Mm long, with row of refractile bodies on the ventral side.

Description. Cell outline pyriform, 7-15 Mm long, fl exible, with two rows of refractile bodies on the ventral side of the cell. The anterior fl agellum is slightly longer than the cell, beats from side to side with entire length, and the basal part of the fl agellum adheres to a rostrum. The posterior fl agellum is about 2.5 -3.5 times the cell length, tapers posteriorly and appears to lie next to the row of the bodies on the ventral side of the cell or to lie in a ventral groove. The fl agellum adheres to the body surface for part of its length and beats slowly from side to side as cells glide. Flagella are of similar thickness and are not acronematic. During gliding the anterior part of the cell is elongated. Strands of cytoplasm were drawn from the posterior end of the cell. Glides with the fl agella in contact with the substratum and may swim like a snake. Rarely observed, but sometimes often observed in late cultures.

Remarks. This species has general characteristics of the genus Cercomonas in that two unequal fl agella emerge near the anterior end of a pliable body which can emit cytoplasmic threads; one is recurrent and adheres to the substratum, the other beats sti ffl y. This species can be distinguished from all other species of Cercomonas by its row of refractile bodies on the ventral side. The composition of the genus is uncertain and we make comparisons only with the most similar nominal taxa. Cercomonas granulatus is distinguished from C. agilis (Moroff, 1904) Lemmermann, 1914 because C. agilis does not have the bodies on the ventral side and has an elongated cell shape (see Lemmermann, 1914). It is similar to C. rhynchophoru s (see Skuja, 1939) in having a long posterior fl agellum and in cell length, but is distinguished by its refractile bodies. This species is also distinguished from Cercomonas ovata (Dujardin, 1841) Tong et al., 1997 by its cell shape, size and the ventral bodies; C. ovata at 12.5-30 Mm is rather larger than C. granulatus . Some species of the genera Amastigomonas, Cercomonas , Dimastigella and Procryptobia have a posterior fl agellum adhering to the ventral surface. This species is similar to Cryptobia coryphaenoideana (see Noble, 1968) found from the stomach of a bathypelagic marine fi sh ( Coryphaenoides acrolepis ) in general appearance and cell length, but is distinguished in having the ventral bodies. Cercomonas resembles Dimastigella , but is usually distinguished by having a ventral groove and strands of cytoplasm drawn from the posterior end of the cell; Dimastigella seems to be rather fl attened compared to Cercomonas . This species is similar in general shape and size to Dimastigella trypaniformis Sandon, 1928 but the basal part of the anterior fl agellum in that species is attached to a discrete rostrum and lacks the refractile bodies on the ventral side. Dimastigella trypaniformis is more spindle-shaped and has no strands of cytoplasm drawn from the posterior end of the cell, and the posterior fl agellum adheres to the cell surface along the entire length of the cell. Dimastigella mimosa ( Frolov et al., 1996) is distinguished from C. granulatus by the lack of ventral bodies.