acritarch

Etymology
From.

Noun

 * 1)  Any small, non-acid-soluble (i.e. non-carbonate, non-siliceous) organic fossil that cannot be classified.

Translations

 * French:
 * Irish: acratarc
 * Occitan: acritarc
 * Portuguese: acritarca
 * Russian:
 * Spanish: acritarco