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
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.