Ditrema longicollis (de Saedeleer, 1934)

Most likely ID: n.a.

 

Synonym: Diplophrys longicollis

 

Sampling location: Simmelried 

 

Phylogenetic tree: n.a.

 

Diagnosis: 

  • shell hyaline, thin, without xenosomes, older cells yellowish or brown
  • in frontal view spherical or broad oval, sometime irregular
  • in lateral view dome-shaped
  • shell with two opposite necks
  • length of shell (inclusive necks) 22–32 µm
  • length of necks 1.7–3.4 µm
  • granofilopodia form a dichotomously branched network
  • nucleus central, with a single nucleolus, older cells numerous nucleoli
  • up to 10 contractile vacuoles
Ditrema-longicollis
Ditrema longicollis

This granulofilose testate amoeba was first described by De Saedeleer as Diplophrys longicollis, but later transferred to Ditrema by Siemensma (s. Ferry Siemensma – Ditrema longicollis). I have found Ditrema longicollis so far exclusively in the Simmelried. It colonizes floating coverslips, where it can be easily observed. The shell with two opposite necks looks spherical or oval, but it is actually dome-shaped, because the amoeba build it on the substrate (in this case the coverslip). In specimens grown on the coverslip, you are looking into the dome-shaped shell from below, so to speak. My specimens were between 24 and 26 µm long (from neck to neck), which is at the lower end of the range given by De Saedeleer.

 

More images and information of Ditrema longicollis: Ferry Siemensma-Microworld-Ditrema longicollis

Ditrema-longicollis

Fig. 1: Ditrema longicollis. L = 26 µm (from neck to neck). A fully extended specimen. CV = contractile vacuoles, Nu = nucleus. Obj. 100 X.

Ditrema-longicollis

Fig. 2: Ditrema longicollis. L = 26 µm (from neck to neck). A second specimen with shorter granofilopods. Note the two, opposite necks (NE 1, Ne 2). Obj. 100 X.

Ditrema-longicollis

Fig. 3: Ditrema longicollis. L = 24 µm (from neck to neck). A third, fully extended specimen with a oval, slightly irregular shell. The shell of this older specimen is colored brown. Obj. 100 X.

Ditrema-longicollis

Fig. 4: Ditrema longicollis. L = 24 µm (from neck to neck). A shell with two specimens after dell division. Obj. 100 X.