Gnetaceaepollenites, Thiergart, 1938

Legrand, Julien, Pons, Denise, Nishida, Harufumi & Yamada, Toshihiro, 2011, Barremian palynofloras from the Ashikajima and Kimigahama formations (Choshi Group, Outer Zone of south-west Japan), Geodiversitas 33 (1), pp. 87-135 : 115

Gnetaceaepollenites sp.

( Fig. 13L )

Gnetaceaepollenites sp. B, Legrand, Palynologie des dépôts Jurassique supérieur et Crétacé inférieur du Japon, et

provinces paléofloristiques du sud-est asiatique: 191, pl. XX, fig. 15 (2009).

OCCURRENCE. — Ashikajima Fm.

DESCRIPTION

Polyplicate pollen grain. Amb ellipsoidal. The exine is constituted of about 15 ribs running through the grain, and describing a senestral “helix” of 180°. The ribs are 1.8-3 µm wide, separated by furrows less than 0.5 µm wide.The ends of the ribs closely gather at each end of the long axis of the grain without joining. Length = 38 µm; width = 27 µm.

BOTANICAL AFFINITIES

Gymnosperms, Gnetales.

Figures

FIG. 13. — Pollen grains, alga and fungus from the Barremian of south-west Japan: A, Pityosporites sp. cf. P. constrictus Singh, 1964, lateral view, Ashikajima Fm, II2b-J34/1; B, Alisporites thomasii (Couper, 1958) Pocock, 1962, polar view, Ashikajima Fm, II2b-O42/3; C, Incertae sedis sp. 2, Ashikajima Fm, II2c-W65/4; D, Balmeiopsis limbatus (Balme, 1957) Archangelsky, 1977, Ashikajima Fm, II2d- N41/2; E, Inaperturopollenites sp., Kimigahama Fm, I1b-U64/4; F-H, Classopollis torosus (Reissinger, 1950) Couper, 1958 emend.