Centropyxis minima, after Bonnet, 1959
Centropyxis minima Bonnet, 1959 *)
Basionym: Centropyxis deflandriana Bonnet var. minima Bonnet, 1959
Diagnosis: Ovoid test, light gray, with circular cross section. Pseudostome in position as eccentric as in the type, with visor strongly thrown back. Wall covered with amorphous siliceous particles, and, in general, more regular than in the type.
Dimensions: Long axis 35-40 µm, small axis 28-34 µm, visor height 5-7 µm, total height 40-47 µm.
Ecology: Like the type, this species is extremely aerophilic. It is very common in the rhizosphere of rupicolous grasses on limestone, rarer on siliceous rocks. Its optimum pH is around 7, compared to 6 for C. deflandriana which is also very rare on limestone substrate.
*) Centropyxis deflandriana Bonnet var. minima Bonnet, 1959 changed to Centropyxis minima Bonnet, 1959.
Note: No new name needs to be established in this case under the International Code of Zoological Nomenclature. Because the name was published before 1961 using the abbreviation var., it is deemed subspecific under Article 45.6.4, unless explicitly proposed as infrasubspecific. As a species-group name, it is simultaneously established at both species and subspecies rank under the Principle of Coordination (Art. 46.1), with the same author, date, and name-bearing type. Accordingly, when treated at species rank, the correct name is Centropyxis minima Bonnet, 1959.