Angiosperm leaves from the Kachaike Formation, Lower Cretaceous of Patagonia, Argentina

Several angiosperm leaf morphotypes are studied for the first time from the late early Cretaceous Kachaike Formation of southern Argentina. The angiosperm component of the flora is totally overlapped by other non-angiosperm groups such as conifers and ferns, which dominate in number of taxa and specimens the plant assemblage. Two new genera, Kachaikenia and Thorphyllum, a new species Rogersia australis, and four unnamed leaf morphotypes represent the angiosperm component of the Kachaike flora. All of them show primitive morphological traits such as microphyllous leaves with entire unlobed margins, pinnate brochidodromous/camptodromous venation patterns with irregular intercostal areas, and relatively disorganized higher venation orders. Comparisons are made with coeval regional and extra-regional floras in order to establish a proper context assessing for a possible angiosperm morphological trend in the Cretaceous of southern South America.