''Ticoa'' is an extinct genus originally assigned to the Cycadales from the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

. Other authors view this genus as a member of the

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of converg ...

seed ferns A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...

Taxonomy

The genus was erected by

Sergio Archangelsky Sergio Archangelsky (27 March 1931 – 10 July 2022) was an Argentine paleobotanist and palynologist. He was a pioneer of modern paleobotany in Argentina, as well as of cuticular morphology and ultrastructure. He was also a corresponding member o ...

based on material from the

Anfiteatro de Ticó formation The Anfiteatro de Ticó Formation is a geological formation from the Deseado Massif in the province of Santa Cruz, Argentina. Paleobiology The Anfiteatro de Ticó preserves a rich and diverse flora including macrofossils, mesofossils, and micro ...

. The genus first comprised two species, ''T. harrisii'' and ''T. magnipinnulata,'' with ''T. lamellata'' being described from the Bajo Grande locality in

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...

, Argentina. The species ''T. magallanica'' was described from the Springhill formation in Chile. ''T. jeffersonii'' was described from

Hope Bay Hope Bay (Spanish: ''Bahía Esperanza'') on Trinity Peninsula, is long and wide, indenting the tip of the Antarctic Peninsula and opening on Antarctic Sound. It is the site of the Argentinian Antarctic settlement Esperanza Base, established i ...

. ''T. lanceolata'' was described much later from the

Description

''Ticoa'' includes large,

bipinnate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

tripinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in ...

leaves with pecopteroid

pinnules A leaflet (occasionally called foliole) in botany is a leaf-like part of a compound leaf. Though it resembles an entire leaf, a leaflet is not borne on a main plant stem or branch, as a leaf is, but rather on a petiole or a branch of the leaf. Co ...

and a robust

rachis In biology, a rachis (from the grc, ῥάχις [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In vertebrates, ''rachis'' can refer to the series of articulated vertebrae, which encase the spinal cord. In this c ...

. The cuticle, either hypostomatous or amphistomatous, presents large

stoma In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bor ...

ta sunken in a pit formed by multiple

subsidiary A subsidiary, subsidiary company or daughter company is a company owned or controlled by another company, which is called the parent company or holding company. Two or more subsidiaries that either belong to the same parent company or having a s ...

and encircling cells.

References

Pteridospermatophyta Controversial plant taxa {{paleo-gymnosperm-stub