Aequitriradites sp.

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 : 110

Aequitriradites sp. ( Fig. 12E )

OCCURRENCE. — Ashikajima Fm.

DESCRIPTION

Zonate trilete microspore. Amb rounded subtriangular. Central body subcircular. Laesurae are not visible. Central body verrucate; verrucae are very small and contiguous (about 1-2 µm in diameter). The exine thickens near the periphery of the central body (about 3-3.5 µm). The zona is thin, granulate, radially folded, with irregular and more or less transparent margins. It is wider in three areas (about five times wider), which gives to the spore a subtriangular shape. No hilum is visible. Equatorial diameter = 45-70 µm; zona width = 2-12 µm.

BOTANICAL AFFINITIES

Bryophyta, Marchantiopsida.

Figures

FIG. 12. — Spores and pollen grains from the Barremian of south-west Japan:A, Cingulatisporites sp.2, proximal face, Ashikajima Fm, SEM-II2c; B, C, Distaltriangulisporites sp., proximal and distal faces, Ashikajima Fm, II2c-N53; D, Contignisporites cooksonii (Balme, 1957) Dettmann, 1963, distal face, Kimigahama Fm, I1a-O51/1; E, Aequitriradites sp., Ashikajima Fm, II2c-Y59/2; F, Aequitriradites verrucosus (Cookson & Dettmann,1958) Cookson & Dettmann,1961,Ashikajima Fm,II2h-J66/4;G, M, Contignisporites burgeri Filatoff, McKellar & Price in Filatoff & Price, 1988, proximal and distal faces, Ashikajima Fm, II2d-P47/4; H, I, Polycingulatisporites reduncus (Bolkhovitina, 1953) Playford & Dettmann, 1965, proximal and distal faces, Kimigahama Fm, I1a-Z52; J, Laevigatosporites sp., lateral view,Ashikajima Fm,II2e-Y60; K, Laevigatosporites ovatus Wilson & Webster,1946,lateral view,Kimigahama Fm,I1c-P35/3;L, Exesipollenites tumulus Balme, 1957, distal view, Kimigahama Fm, I1a-R60/3; N, Callialasporites sp. cf C. ugensis Takahashi & Sugiyama, 1990,Ashikajima Fm, II2f-Y42/3;O, Eucommiidites troedssonii (Erdtman,1948) Potonié, 1958,Kimigahama Fm, I1b-R39; P, Cerebropollenites mesozoicus (Couper,1958) Nilsson,1958, lateral view,Ashikajima Fm,II2a-J61/1d; Q, Alisporites sp., polar view, Ashikajima Fm, II2d-Q59/2; R, Callialasporites dampieri (Balme, 1957) Sukh-Dev, 1961, Ashikajima Fm, II2b-T46/4m. Scale bar: 10 μm.