Morphology, epidermal features and δ13C signature of Lopingian (late Permian) conifers

Abstract

Conifers, the most successful group of Permian gymnosperms, dominate the famous Bletterbach (Dolomites, NE-Italy) plant fossil assemblage, a highly diverse and well-documented late Permian (Lopingian) flora. An integrated analysis of morphology, cuticles and isotope geochemistry was carried out on approximately 50 conifer shoots across five genera (Ortiseia, Majonica, Dolomitia, Pseudovoltzia and Quadrocladus) and eight species, including three (Pseudovoltzia sjerpii, Quadrocladus solmsii, Quadrocladus cf. orobiformis) described for the first time from Bletterbach. Taxon-specific carbon isotope analyses reveal intra-specific and/or intra-generic variability, identifying a unique geochemical composition for Majonica alpina, which may reflect a possible species-specific geochemical signature or adaptation to particular environmental conditions. The isotopic differences observed between leaves and axes indicate the preservation of distinct isotopic ratios in photosynthetic versus heterotrophic tissues, underscoring the importance of sampling multiple plant parts to accurately capture individual and taxonomic isotopic variability. The study of stable isotopes of organic carbon on well-preserved plant remains is enhanced the paleoenvironmental reconstruction of the Bletterbach flora.