Microthorax Engelmann, 1862 (ref. ID; 2013)
Class Kinetofragminophora: Subclass Hypostomata: Order Nassulida: Suborder Microthoracina (ref. ID; 2013)

Synonym Kreyella Kahl (ref. ID; 1618)

[ref. ID; 1601]
Microthoracina with normal cilia, anchor-like extrusomes, and granular or fine-meshed silverline system, and fewer than 10, usually 6 partly interrupted somatic and three preoral kineties. (ref. ID; 1601)

[ref. ID; 2013]
Body outline shape irregular to oval to almost triangular, anterior more or less pointed, posterior end rounded. Flattened with delicate keeled armour, some species with spines. Somatic ciliature reduced, ventral surface with 3 longitudinal ciliary rows. Opening to cytostome in a depression situated in the posterior ventral region, without cytopharyngeal basket. On right of oral depression is a stiff ectoplasmic lip below which there is a small membranelle. There is a tooth-like projection on the left side of the cytostome. Macronucleus spherical and centrally placed. There are usually 2 contractile vacuole which are more or less centrally placed.
Quote; Colin R. Curds "British and other freshwater ciliated protozoa Part I Ciliophora: Kinetofragminophora" Cambridge University Press, 1982 (ref. ID; 2013)

Microthorax simulans Kahl, 1926 (ref. ID; 1308, 1622, 3593) reported year? (ref. ID; 1618)
Description; Decaying plant infusion, also in moss. (ref. ID; 1618)
Measurements; 30-35 um long. (ref. ID; 1618)