Cryptodifflugia oviformis – 26 and 25 µm long
Genus Cryptodifflugia Penard, 1890
Diagnosis: Shell oval, egg-shaped, pyriform with a short neck, circular or oval cross-section, with adhering foreign particles or smooth surface, colorless, yellow or brown, composed of an outer proteinaceous material usually lined, aperture terminal, circular or oval. Pseudopods are in the form of ectoplasmic anastomosing reticulolobopods.
Type species: Cryptodifflugia oviformis Penard, 1890.
Ecology: Fresh water, soil and mosses.
Key to the species
1 | Shell distinctly compressed laterally | 2 |
– | Shell not or slightly compressed laterally | 7 |
2 | Oval aperture | 3 |
– | Circular aperture | C. compressa angustioris |
3 | Shell length 45–63 µm | C. angustastoma |
– | Shell length 32–45 µm | C. paludosa |
– | Shell is smaller than 25 µm | 4 |
4 | Shell width > length | C. compressa australis |
– | Shell width < length | 5 |
5 | Shell lanceolate | C. lanceolata |
– | Shell pyriform | C. brevicolla |
– | Shell ovate | 6 |
6 | Thick organic lip around the aperture | C. compressa |
– | No lip around the aperture | C. compressa ovata |
7 | Shell surface crenulate | 8 |
– | Shell surface not crenulate | 10 |
8 | Shell shape ovoid | 9 |
– | Shell shape globose or subglobose | C. crenulata globosa |
9 | Shell length < 20 µm | C. crenulata |
– | Shell length > 23 µm | C. splendida |
10 | Shell pyriform with prominent neck; surface covered by rare sand grains | 11 |
– | Shell ovoid or globular, without prominent neck | 13 |
11 | Shell surface covered by rare sand grains | 12 |
– | Shell surface smooth | C. collum |
12 | Shell length 16–26 µm; aperture 4–5 µm; neck 1/3 of shell length | C. sacculus |
– | Shell length 27–30 µm; aperture 10–13 µm; neck 1/4 of shell length | C. sacculus sakotschawi |
13 | Lateral sides conical (angular) | C. angulata |
– | Lateral sides rounded | 14 |
14 | Aperture diameter equal to shell width | 15 |
– | Aperture diameter considerably smaller than shell width | 16 |
15 | Shell width equal to shell length | C. pusilla |
– | Shell width considerably smaller than shell length | C. pusilla conica |
16 | Shell length > 40 µm | 27 |
– | Shell length < 40 µm | 17 |
17 | Shell length 8–12 µm | 18 |
– | Shell length higher | 20 |
18 | Shell length higher than shell width | C. minuta |
– | Shell length considerably smaller than shell width | 19 |
19 | Shell surface covered by scarce sand grains | C. patinata |
– | Shell surface smooth | C. bassini |
20 | Shell surface covered by scarce sand grains | 25 |
– | Shell surface smooth | 21 |
21 | Aperture large, its diameter about 1/3–1/4 of maximal shell width | 23 |
– | Aperture small, its diameter about 1/6–1/8 of maximal shell width | 22 |
22 | Aperture diameter 1.5–2.5 µm | C. leachi |
– | Aperture diameter 3.5–4.5 µm | C. vulgaris |
23 | Shell ovoid | 24 |
– | Shell pyriform | C. crenulata glabra |
24 | Shell colorless | C. oviformis |
– | Shell yellowish-brown, oval | C. oviformis fusca |
25 | Shell subsphaerical, width/length ratio > 0.8 | C. horrida |
– | Shell elongated, width/length ratio < 0.7 | 26 |
26 | Shell length 24–27 µm | C. voigti |
– | Shell length 20–24 µm | C. psammophila |
– | Shell length 17–21 µm | C. angusta |
27 | Shell length 40 µm, broadest width at the middle of the shell | C. apiculata |
– | Shell length 55 µm, broadest width at the upper third of the shell | C. valida |
After Bobrov and Mazei, 2017