Reassessment of the cheirolepidiaceous conifer Frenelopsis teixeirae Alvin et Pais from the Early Cretaceous (Hauterivian) of Portugal and palaeoenvironmental considerations

Frenelopsis teixeirae Alvin et Pais is reported from the Lower Cretaceous (Hauterivian) of the Vale Cortiço clay pit, Santa Susana Formation, near Torres Vedras, western Portugal. This is the second occurrence of F. teixeirae, previously known from a single specimen from the Valanginian of the Vale de Lobos Formation exposed at the beach cliff near Sesimbra. The diagnosis is emended and the description is completed based on well preserved leafs and twigs compressions. The specimens consist of leafy axes with whorls of either two or three leaves, each of the abaxial and adaxial surfaces showing a central horseshoe-shaped notch at the base, a trichome of both long hairs and massive papillae covering both outer cuticle surfaces, and stomata also borne on the adaxial cuticle. The dark grey mudstone bed with F. teixeirae is interpreted as a tidal-flat to estuarine deposit. In Portugal Frenelopsis species are known from a wide variety of deposits from the Valanginian to the Maastrichtian reflecting specific habitats.