Cryptomonas paramecium
(Ehrenberg, 1832) Hoef-Emden & Melkonian, 2003
Most likely ID: n.a.
Synonym: Chilomonas paramecium
Sampling location: Ulmisried, Simmelried, Bussenried, Bündtlisried, Purren pond
Phylogenetic tree: Cryptomonas paramecium
Diagnosis:
- body elongate-ovate, broader anteriorly than posteriorly
- length 14–28 µm
- two flagella equal in length, slightly shorter than cell
- anterior cytopharynx surrounded by refractile ejectisomes
- nucleus is located posteriorly to the cytopharynx
- small extrusomes under cell membrane
- contractile vacuole is located anteriorly
- often two refractile Maupas’ bodies
- rotates while swimming, can also swim backwards, occasionally jumps backwards
- frequently cell is filled with starch grains
- cell colorless, without chloroplasts
Cryptomonas paramecium (until 2003 Chilomonas paramecium) is a heterotrophic cryptomonad that has all the characteristics of the genus Cryptomonas except for the chloroplasts. The colorless flagellate feeds on dissolved nutrients (saprophytically) and on bacteria. It can also be grown in pure nutrient solutions. The species is common in all my localities where there are decaying plant masses. Mass development sometimes occurs in old samples.
Fig. 1: Cryptomonas paramecium. L = 21 – 27 µm. A sample with a mass development. Obj. 100 X.
Fig. 2 a-c: Cryptomonas paramecium. L = 26 µm. A freely swimming specimen in frontal view (a, b) and lateral view (c). CV = contractile vacuole, EJ = cytopharynx with ejectisomes, MB = Maupas’ bodies, SG = starch grains. Obj. 100 X.