Pileolus tuberosus
P. tuberosus from Coûteaux and Chardez, 1981

Genus Pileolus  Coûteaux and Chardez, 1981

Diagnosis: Test with arched acrosome. Pseudostome with an outwardly rolled collar formed at the periphery by elongated small scales and internally by a row of scales carrying a lateral hook (this hook scale structure also exists in the genus Trinema). Test composed as in the genus Trinema by scales of two types, large and small; the small scales filling the intervals between the large ones. Large scales have a large central thickening refracting in an optical microscope and giving the test a bumpy look.

Remarks: Despite its very original morphology, the genus Pileolus has a number of convergent characters with those of the genus Trinema, namely the dimorphism and disappearance of the parietal oral scales. It differs on the one hand by the shape of the pseudostome rolling outwards while the pseudostome of Trinema tends to wrap it towards the interior of the test and on the other hand, by the central thickening of the large parietal scales . Although no living organism has been observed, it is likely that this new genus belongs to the family Euglyphidae.

Type species: Pileolus tuberosus
One known species.

Ecology: rhizosphere of a Bromelia in primary forest, French Guiana.

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