Ticoa

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]

Ticoa Temporal range: Aptian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Plantae
(unranked):	?Cycadophyta
(unranked):	?Cycadopsida
Order:	?Cycadales
Genus:	†Ticoa S.Archang.[1]
Species
†T. harrisii (type species) †T. magnipinnulata †T. lamellata †T. magallanica †T. jeffersonii †T. lanceolata

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.