world of amoeboid organisms

Cryptodifflugia oviformis
Cryptodifflugia oviformis
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

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