Revision of the Lower Cretaceous ovulate cone Pinus belgica Alvin (1960), one of the oldest representatives of Pinus

Pinaceous ovulate cones have an abundant fossil record since the middle Lower Cretaceous. Pinus belgica Alvin (1960) is considered the second oldest representative of the genus Pinus. This taxon has thus often been included in phylogenetic and molecular dating analyses although its age and stratigraphy are uncertain. We redescribe this important species and discuss its spatiotemporal occurrence (middle Barremian to late Albian of the Mons Basin, Belgium). Several anatomical features are updated (resin canals abaxial to vascular bundles, bract and ovuliferous scale separating medially first, resin canals distributed at the edge between pith and vascular cylinder). We show that the species does possess the diagnostic characters of Pinus (e.g. thick apophysis, dorsal umbo, resin canals abaxial to vascular tissue, bract and scale traces united at origin) and there are currently no arguments to question its inclusion within the genus Pinus. Yet, this species should be considered with caution in molecular dating analyses, as the broad temporal uncertainty is likely to affect the precision of deep nodes within Pinaceae.