New petrified gymnosperms from the Permian of Maranhão (Pedra de Fogo Formation), Brazil: Ductolobatopitys nov. gen. and Kaokoxylon

Continuing the study of petrified gymnosperm trunks recovered from the Pedra de Fogo Formation, we identify here two new taxa from the Permian deposits of the Parnaíba Basin, northeastern Brazil. One taxon is an endemic form named Ductolobatopitys mussae Conceição, Neregato et Iannuzzi, nov. gen., nov. sp., characterized by solenoid, lobed and non-septate heterocellular pith, cauline bundles with endarch maturation, and secondary xylem with araucarian radial pitting on the tracheid walls. The other form is assigned to the genus Kaokoxylon, which has been recorded from most of Gondwana, including the Parnaíba Basin, but is recorded for the first time from the Pedra de Fogo Formation with the new species Kaokoxylon brasiliensis. It is characterized by solid, non-septate heterocellular pith with sclerenchyma cells, endarch cauline bundles, and uni-to triseriate radial pitting on the walls of the tracheids. The sedimentological interpretations of the outcrops where the fossils were collected indicate that these plants lived on the shores of large continental lakes, with relatively high humidity but possibly periods of drought. These inferences are supported by growth interruptions in the secondary xylem, the presence of calamitalean and tree-fern stems, and microbialites that crop in the same area. These new finds not only increase the known diversity of the flora in the Pedra de Fogo Formation, but also provide more accurate information for understanding the floristic elements that formed the subtropical flora during the Cisuralian in this basin in Western Gondwana.