glossopterids

Glossopterids are an extinct group of seed plants belonging to the order Glossopteridales, commonly described as seed ferns, though they are not true ferns. They lived during the Permian period, roughly 299 to 251 million years ago, and were a dominant component of Gondwanan floras. Fossils have been found across the southern continents that once formed this supercontinent, including Antarctica, Australia, India, Africa, and South America.

As seed plants, glossopterids reproduced by seeds rather than spores and are regarded as early gymnosperms. The best-known members are the leaves assigned to Glossopteris, the type genus, though other genera are associated with the group, such as Gangamopteris and Vertebraria (the latter known from root structures).

Leaves are typically tongue- or oblong-shaped with a prominent midrib and a network of veins. They could be broad and leathery, with sizes ranging widely. Reproductive structures include megasporophylls bearing ovules and, in some fossils, clustered seed-bearing organs that indicate a seed-fern habit.

Biogeography and significance: The global distribution of glossopterid fossils across widely separated landmasses is a central line of evidence for the existence of the ancient supercontinent Gondwana and for plate-tectonic theory. The plants also provide information about Permian climates, which in many Gondwanan regions were cooler and more temperate than later in the Mesozoic.

Decline and legacy: Glossopterids largely disappeared by the end of the Permian, with the Permian–Triassic extinction event contributing to their decline. Their fossil record remains important for reconstructing ancient biogeography and the evolution of seed plants.