Epipyxis leickii
(Gessner) Hilliard & Asmund, 1963
Most likely ID: n.a.
Synonym: Hyalobryon leickii
Sampling location: Pond of the convent Hegne
Phylogenetic tree: Epipyxis leickii
Diagnosis:
- cells spindle-shaped
- anterior end hyaline and obliquely truncated
- cells attached with tapered end to base of lorica
- lorica 25–30 µm long, cylindrically, with 1–3 growth rings
- aperture of lorica funnel-shaped
- two chloroplasts of different size
- 1–2 contractile vacuoles near mid-body
- one eyespot
- two flagella of different length
- solitary or in spherical colonies, epiphytical
Epipyxis leickii was first found by Gessner (1932) in a eutrophic pond on the island of Hiddensee (Germany). He described the species as Hyalobryon leickii. The genera Epipyxis and Hyalobryon were later united, with the generic name Epipyxis having priority.
So far I have only found Epipyxis leickii in the pond at the convent Hegne. In the samples I usually find small colonies of 10–20 specimens growing epiphytically on filamentous algae (s. fig. 2). Only rarely do I find solitary specimens (s. fig. 1).
In contrast to the genus Dinobryon, the loricae of the genus Epipyxis are composed of individual growth rings. In Epipyxis leickii, the rings that form the aperture of the lorica are widened in a funnel shape. The spindle-shaped cells have a clear, hyaline apical end, which sometimes appears snout-shaped.
Fig. 1: Epipyxis leickii. L = 30 µm (of lorica). A solitary specimen attached to the gelatinous tube of Encyonema leibleinii. CV = contractile vacuole, Chl = chloroplast. Obj. 100 X.
Fig. 2: Epipyxis leickii. L = 26–28 µm (of loricae). A colony of several specimens attached to an filamentous alga. CV = contractile vacuoles, Nu = nucleus. Obj. 100 X.