Nilssonia BRONGN., 1825

Čepičková, Jana & Kvaček, Jiří, 2020, Two Cycads Nilssonia Mirovanae Sp. Nov. And Pseudoctenis Babinensis J. Kvaček From The Cenomanian Of The Bohemian Cretaceous Basin (The Czech Republic) As Indicators Of Water Stress In The Palaeoenvironment, Fossil Imprint 76 (2), pp. 315-324 : 317

Genus Nilssonia BRONGN., 1825

T y p e. Nilssonia brevis BRONGN., 1825, p. 218, pl. 12, fig. 4.

R e m a r k s. This genus was revised by Van Konijnenburg-van Cittert et al. (2017); ortography of the name was discussed and conserved as Nilssonia (with double ‘s’) by Wang (2011).

The studied material is a fragment of an isolated straplike entire-margined pinna showing parallel arrangement of simple veins, and cuticle with papillae on subsidiary cells. These characters indicate genera Zamites BRONGN, 1828 , Pseudoctenis , Nilssonia or Tilingia WATSON et CUSACK, 2005 , nom. illegit. (non Tilingia REGEL etTILING 1859, Nouv. Mém. Soc. Imp. Naturalistes Moscou 11: 97). Other genera, such as Ctenis , Jirusia and Dioonopsis J.HORIUCHI et T.KIMURA differ from the studied material more profoundly in venation pattern and the presence of marginal teeth. The studied material differs from Zamites (and all bennettites) in absence of syndetocheilic stomata. The material in hand differs from the genus Tilingia in having stomata irregularly scattered across the pinna width. The pinna of the studied material does not differ in macromorphology from Pseudoctenis , but according to other observations, Pseudoctenis does not have papillae on subsidiary cells. This character does occur in some species of Nilssonia ( Daber 1957, Van Konijnenburgvan Cittert and van der Burgh 1989, Barbacka 2001).