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Centropyxis

Family Centropyxidae Jung, 1942

Diagnosis: Lobose testate amoebae with shell of granular organic material, dorsally with more or less mineral particles or diatoms, ventrally smooth or with much smaller grains; dorsal surface rounded, ventral side flat to concave, with a ventral aperture, which may be circular to uneven, but displaced towards one end; shell may be flattened at the apertural end; at the posterior end or all around the periphery some spines may be present.

Type genus: Centropyxis.

Key to the genera
1
Aperture surrounded by a funnel-shaped construction
Conicocassis
Aperture not surrounded by a funnel-shaped construction
2
2
Aperture invaginated
3
Aperture not invaginated
Proplagiopyxis
3
Anterior walls of the aperture are not attach to the dorsal side
Anterior walls of the aperture are attached to the dorsal side by one or more struts
Armipyxis **)

*) For the time being I will consider all species with internal struts as belonging to this genus.
**) The genus Armipyxis was created by Dekhtiar (2009) to accommodate all species with internal struts. In my opinion that is not correct, because if you use this morphological character, you leave strut-less species in the Centropyxis group that are morphologically much closer to species with internal struts than many other Centropyxis species.

Centropyxis discoides
Test of Centropyxis discoides, see detail below
Centropyxis discoides
The test consists of an organic layer of granular structure with embedded xenosomes, here several kind of diatoms, some with remnants of the chloroplast still present.
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