A new cheirolepidiaceous microsporangiate cone Classostrobus archangelskyi with in situ pollen from the Lower Cretaceous of Figueira da Foz Formation, central-western mainland Portugal

Abstract

A new cheirolepidiaceous conifer microsporangiate cone Classostrobus archangelskyi is described from the Carregueira opencast clay pit complex near the village of Juncal, in the Lusitanian Basin of central-western mainland Portugal. The plant-bearing horizon belongs to the Famalicão Member of the Figueira da Foz Formation, considered to be of Lower Cretaceous (upper Aptian–lower Albian) age. The new microsporangiate cone is characterised by the presence of distinctive and unusual pollen assigned to the genus Classopollis. The microsporangiate cone is ovoid and small, comprising only a few microsporophylls, each with a stalk and deltoid head bearing 4–5 pollen sacs. The new Portuguese species is compared to other microsporangiate cones attributed to the genus Classostrobus. The Classopollis pollen grains found in situ are characterised by a microechinate sculpture and typical ultrastructure. The pollen grains were studied using SEM, TEM and transmitted light microscopy. The studied pollen shares strong similarities with Classopollis martinotii, Classopollis torosus, but particularly with Classopollis noelii. The new microsporangiate cone Classostrobus archangelskyi co-occurs with frenelopsid leafy shoots of Frenelopsis antunesii, and their common association is suggested.