Epipyxis
[ref. ID; 4878]
Type species; Epipyxis utriculus Ehrenberg (ref. ID; 4878)
- Epipyxis alaskana Hilliard & Asmund (ref. ID; 4878)
- Epipyxis cf. kenaiensis (ref. ID; 4878)
- Epipyxis ramosa (Lauterborn) Hilliard & Asmund (ref. ID; 4878)
- Epipyxis thamnoides Ikavalko, Thomsen & Carstens, 1996 (ref. ID; 4878 original paper)
- Epipyxis utriculus Ehrenberg (ref. ID; 4878)
Descriptions
This species is characterized by a smooth lorica and outwardly flaring scales forming a collar-like structure at the opening of the lorica. In overall morphology and dimensions (25.5x7.2 um; opening 12.8 um) the Greenland specimens is in general agreement with type material of E. alaskana (26-32x4.6-7.4 um; opening 8.5-12.4 um; Hilliard & Asmund). (ref. ID; 4878)
Epipyxis cf. kenaiensis (ref. ID; 4878)
Descriptions
The empty lorica is in overall morphology reminiscent of E. kenaiensis Hilliard & Asmund. However, the Greenland specimen (23.5x8-10.5 um) is significantly wider than E. kenaiensis (4.5-8 um). (ref. ID; 4878)
Epipyxis thamnoides Ikavalko, Thomsen & Carstens, 1996 (ref. ID; 4878 original paper)
Diagnosis
Phototrophic species with heterokont flagellation. The cell inhabits a long, tube-like, morphologically highly variable lorica (55-112x9-10.5 um) formed by circular-elliptical scales. The lorica is less wide (5.6-6.4 um) at the proximal end. Colony formation of ca. 40 cells observed once. (ref. ID; 4878)
Remarks
This taxon is distinguished by its long, tube-like lorica constructed of large, circular-elliptical scales. Dimensions of the lorica are 55-112x9-10.5 um. The lorica attenuates towards the proximal end (width 5.6-6.4 um). Due to the considerable overall length and the apparent flexibility of the wall, the lorica shows pronounced morphological variability. The cell is located within the upper one third of the lorica. Colony formation (ca. 40 cells) was observed once. All other cells were either solitary or occuring in doublets. This is likely to be an artefact caused by the preparational procedures. The species was seen only in dried whole mounts for light microscopy. The presence of a choloroplast was verified by means of epifluorescence microscopy. Nygaard (1978) recorded a bush-like, colony forming species, E. ramosa (Lauterborn) Hilliard & Asmund, from a South Greenland lake. However, this taxon differs from Epipyxis thamnoides in having irregularly arranged, more or less elliptical or elongate scales forming a somewhat smaller lorica (Hilliard & Asmund 1963): Length 42-73 um, width 2.5-3.5 um (distal end), 4-6.5 um (middle pat), 4.8-8.5 um (proximal end). (ref. ID; 4878)
Etymology
"thamnoides"=bush-like. (ref. ID; 4878)
Descriptions
The cells are solitary and dwell in a lorica that narrows towards the apical end. The sturdy, funnel-shaped lorica consists of elliptical scales and carries a conspicuous three-lobed holdfast. Epipyxis utriculus is the type species of the genus, and known to have a highly variable lorica morphology (Hilliard & Asmund 1963). (ref. ID; 4878)