Pterospermella sp. (Fig. 13P)

OCCURRENCE. — Ashikajima Fm (rare).

DISTRIBUTION. — This genus is known from the Precambrian to possibly Holocene.

DESCRIPTION

Flattened lenticular body. The central body is biconvex and darker than the folded equatorial membrane that surrounds it. Length = 38 µm; width = 30 µm; central body (length × width) = 15 × 10 µm; equatorial membrane width = 10 µm.

BOTANICAL AFFINITIES

Pterospermatales, Pterospermellaceae of marine environment.