Nilssoniopteris crassiaxis Yi Zhao et S.H.Deng in Zhao, Deng, Shang, Leng, Lu, Fu & Ma

Plant Fossil Names Registry Number: PFN000198


Authors: Y. Zhao & S. Deng

Rank: species


Reference: Zhao, Y., Deng, S., Shang, P., Leng, Q., Lu, Y., Fu, G. & Ma, X. (2018): Two new species of Nilssoniopteris (Bennettitales) from the Middle Jurassic of Sandaoling, Turpan-Hami Basin, Xinjiang, NW China. – Journal of Paleontology 92(4): 525–545.

Page of description: 535

Illustrations or figures: figs 9-12


Holotype SDL-98-L2, Research Institute of Petroleum Exploration and Development, Beijing, China
Figures: fig. 9.13

Note: Paratypes: SDL-98-4-11 (Fig. 9.1), SDL-98-409 (Fig. 9.3), SDL-98-4-13 (Fig. 9.6), SDL-98-L14 (Fig. 9.10), and SDL-98-L1 (Fig. 9.11).

Original diagnosis/description

Leaves petiolate, entire-margined, long strapshaped, but with the widest part at the apical portion. Petiole stout. Lamina gradually and very slowly narrowing from the widest part to the base while narrowing towards the apex more quickly. Leaf base cuneate, apex likely obtuse to obtuserounded. Midrib at leaf base stout, accounting for one-third to one-half width of leaf base, tapering gradually towards leaf apex. Midrib surface bearing irregular transverse corrugations. Lamina attached to the adaxial side of midrib but leaving the central part exposed. Secondary veins thin, conspicuous, simple or forked once, twice, or even three times, with a few veins forking and then merging and a few others merging with their neighboring veins. Leaf hypostomatic. Epidermal areas along veins and between veins distinct on both surfaces. Epidermal cells on the adaxial surface square, rectangular, or more or less isodiametric, with anticlinal walls sinuous, U-shaped, or Ω-shaped. Epidermal cells along veins on the abaxial surface rectangular or elongated, between veins irregularly shaped, with anticlinal walls strongly sinuous, U- or Ω-shaped. Stomata syndetocheilic, mostly vertical or oblique to veins but occasionally parallel to veins. Trichome bases consisting of 1–3 cells occurring numerously along veins and between veins of the abaxial epidermis. Epidermal cells on the abaxial surface of midrib having straight anticlinal walls, with numerous trichome bases present.


Specific epithet is taken from the Latin crass, strong, and axis, midrib.


Jurassic, Middle Jurassic
Xishanyao Formation


Sandaoling Coal Mine, Xinjiang Uygur Autonomous Region

Plant fossil remain

macro- and meso-fossils-embryophytes except wood


Use comments to notify PFNR administrators of mistakes or incomplete information relevant to this record.