Komlopteris: A persistent lineage of post-Triassic corystosperms in Gondwana

Abstract

Komlopteris is a genus that includes the youngest representative of the so-called ‘seed ferns’, an informal group of gymnosperms that were prevalent during the Mesozoic but largely went extinct at the end of the Cretaceous. New fossil material, morphological data, and an extensive literature review allowed us to clarify the systematics of Gondwanan post-Triassic leaves of the Komlopteris lineage that were formerly assigned to diverse genera. Trends in diversity and distribution were identified. Ten species of Komlopteris were recognized in Jurassic to Eocene strata across Gondwana. Earliest records of the genus derive from South America soon after the end-Triassic extinction event. The genus reached its peak diversity and range in the Late Jurassic and Early Cretaceous and declined markedly after the Aptian. Its youngest representation is in mid-Cretaceous to Eocene deposits of southeastern Gondwana. Although never dominant, Komlopteris represents an important subsidiary component of austral Jurassic–Paleogene plant fossil assemblages. Striking morphological similarities to Dicroidium and Kurtziana, and co-occurrence with low concentrations of Alisporites/Falcisporites-type pollen, suggest that Komlopteris was a gymnosperm belonging to Umkomasiales (=Corystospermales) that survived the end-Triassic and end-Cretaceous biotic crises in climatically buffered humid habitats of high southern latitudes. Arthropod induced leaf damage was rare on Komlopteris foliage and recognized only in two Late Jurassic–Early Cretaceous species.