Canrightia resinifera gen. et sp. nov., a new extinct angiosperm with Retimonocolpites-type pollen from the Early Cretaceous of Portugal: missing link in the eumagnoliid tree?

Abstract

Canrightia resinifera gen. et sp. nov. is based on numerous fossils from several Early Cretaceous localities of western Portugal (Arazede, Buarcos, Catefica, Famalicão, Juncal, Vale de Agua, Vila Verde 2). Scanning electron microscopy (SEM) combined with non-destructive synchrotron radiation-based X-ray tomographic microscopy (SRXTM) has revealed critical external and internal features. Flowers are bisexual with a single whorl of tepals, laterally fused to form a hypanthium. The ovary is semi-inferior and syncarpous formed from two to five carpels, each carpel with a single pendant and orthotropous ovule. Ovules are endotestal-endotegmic with a distinct crystalliferous endotesta and an endotegmen that develops into a prominent endothelium. Pollen is of the Retimonocolpites-type with long extended colpus, semi-tectate reticulate pollen wall, homobrochate reticulum and columellate infratectal layer. Canrightia is in many respects similar to the extinct genus Zlatkocarpus, but is distinguished by its syncarpous organisation and up to five ovules per ovary. Pollen characters and many floral features in Canrightia are plesiomorphic indicating a basal position in the angiosperm phylogenetic tree. Comparison with extant and extinct taxa shows that Canrightia belongs to an extinct lineage and character optimisation suggests a position of Canrightia close to the root of the eumagnoliid tree with particular similarities to Chloranthaceae and Piperales.