Frenelopsis callapezii, a New Cheirolepidiaceous Conifer from the Lower Cretaceous (Upper Aptian–Lower Albian) Sedimentary Deposits of Lusitanian Basin in Western Portugal: Systematic and Palaeoenvironmental Implications

Abstract

Premise of research. Cheirolepidiaceous plants are particularly abundant and diverse in Lower Cretaceous strata of the Iberian Peninsula. These include vegetative shoots, reproductive structures, and dispersed pollen grains. The new material described here is from the upper Aptian–lower Albian of the Figueira da Foz Formation in western Portugal. Methodology. The fossil specimens were isolated from sedimentary rock samples by sieving in water and then cleaned with hydrofluoric and hydrochloric acids, following standard techniques. Cuticle analysis was carried out to distinguish the new species from similar taxa previously described from the Iberian Peninsula and elsewhere. Light microscopy and scanning electron microscopy were used to study morphological and anatomical features. Pivotal results. The new species Frenelopsis callapezii is described based on morphological characters and cuticular features of vegetative leafy axes. Its ecological conditions are reconstructed and discussed in comparison with those of other Cheirolepidiaceae species. Conclusions. Frenelopsis callapezii supports previous interpretations that frenelopsids were a common and diversified group of conifers in Early Cretaceous floras occurring in coastal areas of the Tethys Ocean. They were able to flourish in a wide range of habitats. Frenelopsis callapezii is interpreted to have grown in alluvial plain environments, where wildfires occurred infrequently.