Ticoa is an extinct genus originally assigned to the Cycadales[1] from the Early Cretaceous of Argentina, Chile, and Antarctica. Other authors view this genus as a member of the polyphyletic "seed ferns".[2]

Taxonomy

The genus was erected by Sergio Archangelsky based on material from the Anfiteatro de Ticó formation.[1] The genus first comprised two species, T. harrisii and T. magnipinnulata, with T. lamellata being described from the Bajo Grande locality in Patagonia, Argentina.[3] The species T. magallanica was described from the Springhill formation in Chile.[4] T. jeffersonii was described from Hope Bay in Antarctica.[5] T. lanceolata was described much later from the Anfiteatro de Ticó formation .[6]

Description

Ticoa includes large, bipinnate or tripinnate leaves with pecopteroid pinnules and a robust rachis. The cuticle, either hypostomatous or amphistomatous, presents large stomata sunken in a pit formed by multiple subsidiary and encircling cells.

References


No tags for this post.