Kladistamuos golondrinensis nov. gen. et comb., a fertile foliage from the mid to late Permian of Patagonia, Argentina

• Eremopteris golondrinensis leaves with attached reproductive organs have been found.
• Eremopteris is no longer available for these Gondwanan specimens.
• Therefore, a new genus Kladistamuos is here proposed.
• As a consequence the new combination Kladistamuos golondrinensis is required.
• Kladistamuos is a Permian plant fossil from Gondwana with pteridospermous affinity.

Dichotomous rachises bearing Eremopteris golondrinensis Archangelsky foliage in organic connection with probable microsporangiate structures were collected in the mid to late Permian La Golondrina Formation at Laguna Castellanos locality in southern Patagonia. The fertile bodies are receptacles slightly curved distally that bear 4–5 sessile, erect and oblong to elliptic sporangia-like bodies parallel to each other. They are fused laterally and apparently are enveloped by a delicate layer of conjunctive tissue that holds them together and have no visible dehiscence marks. These structures are here interpreted as putative microsporangiate organs. The novel information allows the emendation of the diagnosis of E. golondrinensis by adding new data on the morphology of the frond and its reproductive organs. As the genus Eremopteris has recently been emended excluding this species, a new genus, Kladistamuos with a new combination, K. golondrinensis is proposed here. Kladistamuos is therefore considered to be another SW Gondwana plant fossil of a putative ‘pteridospermous’ affinity, having distally attached fertile organs that differentiate it from the Euramerican species of Eremopteris.