A new cheirolepidiaceous conifer Pseudofrenelopsis salesii sp. nov. from the Early Cretaceous of Brazil (Romualdo Formation, Araripe Basin): Paleoecological and taphonomic significance

Pseudofrenelopsis is a genus of the conifer family Cheirolepidiaceae, whose temporal distribution was restricted to the Early Cretaceous. Its set of features correspond to adaptive responses to rather unstable and stressful environmental conditions, such as aridity and/or groundwater salinity. In this paper, we describe Pseudofrenelopsis salesii sp. nov. from the Albian Romualdo Formation of the Araripe Basin, northeastern Brazil, based on anatomical analyses of the stem and leaf epidermis of a new specimen using scanning electron microscopy. The unique combination of features of P. salesii sp. nov., such as internodes of uniform sizes, completely sunken stomatal apparatuses, non-papillate subsidiary cells, and multi-layered hypodermis, distinguishes it from the remaining species of the genus, including Pseudofrenelopsis capillata from the late Aptian Crato Formation of the same basin. The new fossil species represents both an additional record of Cheirolepidiaceae in the Araripe Basin and the first representative of Pseudofrenelopsis formally described from the Romualdo Formation.