Microthyriacites sp., 1947

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 : 117-118

Microthyriacites sp. ( Fig. 13Q )

OCCURRENCE. — Ashikajima and Kimigahama Fm.

DESCRIPTION

Disc-like body, brown-colored, with radially arranged cell rows; the margins of the body are thin and irregular. The “ostiole” is not distinct, but a hole in the center of the disc is present, formed by dissolving of the central cells. Cells are square to elongated, without pore, 3-10 µm long and 2.5 µm wide. Cells of the central part of the disc are thicker. Equatorial diameter = 65-70 µm.

BOTANICAL AFFINITIES

Dothideomycetes, Microthyriales . Epiphyllous fungi.

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. Burger, 1965 (F, distal polar view, Ashikajima Fm, SEM-II2a; G, distal polar view, Ashikajima Fm, II2c-H32/1; H, tetrad, Ashikajima Fm, SEM-II2a); I, Cycadopites minimus (Cookson, 1947) Pocock, 1970, Ashikajima Fm, II2e-U64; J, Cycadopites sp., Kimigahama Fm, I1a-X30; K, Ephedripites montanaensis Brenner, 1968, Ashikajima Fm, II2c-N35/4h; L, Gnetaceaepollenites sp., Ashikajima Fm, II2a-S47/1a; M, Corollina sp.,tetrad,Kimigahama Fm, I1a-X42; N, O, Incertae sedis sp. 1, group with detail,Ashikajima Fm,SEM-II2a; P, Pterospermella sp., Ashikajima Fm, II2b-O65; Q, Microthyriacites sp., Ashikajima Fm, II2e-R63/4. Scale bars: 10 μm.