Monosulcites scaber Kimyai, 1966

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 : 116

Incertae sedis sp. 2

( Fig. 13C )

Incertae sedis sp. G, Legrand, Palynologie des dépôts Jurassique supérieur et Crétacé inférieur du Japon, et provinces paléofloristiques du sud-est asiatique: 195, pl. XXI, fig. 7 (2009).

OCCURRENCE. — Ashikajima Fm.

DESCRIPTION

Pollen grain. Amb oval in polar view. An eight shape wide median sulcus with rounded ends, runs through the grain. In the middle part of the grain, the edges of the sulcus strongly widen (until 10-12 µm), and can fold one over the other. This thickening can widen progressively or quite abruptly. The exine is psilate (about 1.5 µm thick). Length × width = 40-50 × 30- 35 µm; longitudinal thickenings (length × width) = 25 × 10-12 µm.

REMARKS

These grains have similarities with Cycadopites, but the folded lips that can be observed here on some grains are much more developped. The genus Entylissa Naumova ex Ischenko, shows developped lips, but slenderer and more ornamented than in Incertae sedis sp. 2. McGregor (1965) figured a pollen grain similar to our species: cf. Ginkgocycadophytus caperatus (Luber, 1941) Samoilovich, 1953 (pl. 5, fig. 25), from the Upper Jurassic of Canada. Monosulcites scaber Kimyai, 1966 reported from the Cretaceous of New Jersey, USA ( Kimyai 1966), also shows great similarities to our species.

BOTANICAL AFFINITIES

Gymnosperms.

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.