Trachelomonas lacustris
Dreżepolski, 1925
Most likely ID: n.a.
Synonym: Trachelomonas cylindrica var. gordeievii, Trachelomonas cylindrica var. hispidula
Sampling location: Simmelried
Phylogenetic tree: Trachelomonas lacustris
Diagnosis:
- lorica ellipsoidal to cylindrical, poles rounded
- length 25–30 µm, width 12–15 µm
- apical pore without or with flat, smooth collar
- lorica yellowish-brown
- lorica densely punctate, sometimes with short papillae
- several chloroplasts with pyrenoids
- eyespot large
- flagellum of body length
I find Trachelomonas lacustris only sporadically at Simmelried. So far, I have not been able to record this species at any of my other sites.
A characteristic feature of Trachelomonas lacustris is the punctate structure of the lorica, which bears no spines. A collar around the pore is not developed; at most, there is a thickening, but it is smooth. The lorica has a yellowish-brown color. Several disc-shaped chloroplasts are present, appressed to the lorica (s. fig. 1 d). Each chloroplast contains a pyrenoid (s. fig. 1 c). The paramylon grains are small and broadly oval or somewhat angular in shape (s. fig. 1 d). The nucleus is centrally located (s. fig. 1 c).
Fig. 1 a-e: Trachelomonas lacustris. L = 30 µm. Different focal planes of a specimen which has shed off the flagellum. Note the pyrenoids (PY) in the chloroplasts (Chl) and the punctate surface of the lorica (e). ES = eyespot, Nu = nucleus, PG = paramylon grains. Obj. 100 X