Note on the preservational nature of ornamentation in sphaeromorphs assignable to Tapajonites Sommer & van Boekel, 1963 (Prasinophyta?)

Abstract. Assemblages of Middle Devonian (Givetian) phytoplankton from the Holy Cross Mountains include sphaeromorphs possessing blister-like ornamentation typical of the genus Tapajonites Sommer & van Boekel, 1963. Study of the sculptural elements under high magnification indicates the presence of patterns resembling impressions of pyrite crystals. It is suggested that ornamentation in Tapajonites, or at least in some sphaeromorphs assignable to that genus, is of a secondary nature.