Barremian palynofloras from the Ashikajima and Kimigahama formations (Choshi Group, Outer Zone of south-west Japan) Author Legrand, Julien Author Pons, Denise Author Nishida, Harufumi Author Yamada, Toshihiro text Geodiversitas 2011 2011-03-31 33 1 87 135 http://dx.doi.org/10.5252/g2011n1a6 journal article 7707 10.5252/g2011n1a6 31ed99a5-9135-40a2-92a4-64217d9de577 1638-9395 4597011 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 . FIG. 14. — Percentages of nine palynomorph groups: A , Ashikajima Formation; B , Kimigahama Formation, south-west Japan. BOTANICAL AFFINITIES Pterospermatales, Pterospermellaceae of marine environment.