New petrified gymnosperms from the Permian of Maranhão (Pedra de Fogo Formation), Brazil: Novaiorquepitys and Yvyrapitys

Abstract

Anatomically preserved gymnosperm stems are relatively abundant in the Permian outcrops of the Parnaíba Basin, but their anatomy has rarely been studied in detail. Here we describe two new fossil gymnosperm trunks from the Lower Permian (Cisuralian) strata of the Pedra de Fogo Formation in the municipality of Nova Iorque, southern Maranhão State, northeastern Brazil. Two new genera et species are described, Novaiorquepitys maranhensis and Yvyrapitys novaiorquensis. These taxa have a broad, non-septate pith containing sclerenchyma and secretory cells, a parenchyma sheath, and a system of lacunae. Pycnoxylic secondary xylem with growth interruptions and the radial bordered pits on the tracheid walls are araucarian and mixed types. The recognition of two endemic forms indicates both a high degree of endemism for the flora of the Pedra de Fogo Formation and a higher taxonomic diversity of gymnosperm woods than hitherto noted. In addition, the anatomical characters of these taxa, together with sedimentological data and the presence in the same area of plants that live on the banks of water bodies or in wetlands (e.g., tree ferns and tree-calamitaleans), indicate that these woody plants lived near the shores of large lakes. These findings show that studies of Paleozoic woods in this region are potentially valuable.