Agathoxylon santanensis sp. nov. from the Aptian Crato fossil Lagerstätte, Santana Formation, Araripe Basin, Brazil

The study of a petrified twig under high-resolution optical microscopy allowed for the first formal record of the morphogenus Agathoxylon for the late Aptian Crato Member (Santana Formation, Araripe Basin, northeastern Brazil) and the description of a new species, Agathoxylon santanensis. The wood is characterized by mostly (95%) araucarian triseriate alternate bordered pits with hexagonal boundaries in a compact arrangement, and cross-field pits with araucarioid organization. In addition to Agathoxyon-type of xylem, the preservation of a belt of stone cells and axial resin ducts in the non-functional phloem, and an attached leaf with parallel venation showing longitudinally oriented stomata point to a probable Araucariaceae affinity. The presence of Agathoxylon xylem associated with phloem of Araucariaceae affinity in the Tropical-Equatorial Hot Arid belt indicate that the parent plants survived in different climatic zones in the Early Cretaceous of Western Gondwana, from periequatorial to warm and cool-temperate belts. The general growth pattern suggests that the growth interruptions zones were caused by temporary water stress, which was the limiting factor for favorable growing. •Agathoxylon is reported for the first time for the Aptian Equatorial Arid belt.•Agathoxylon santanensis amplifies the paleobiogeography of the genus.•Bark and leaf patterns indicate probable Araucariaceae affinity.