Hubbardiastrobus cunninghamioides gen. et sp. nov., Evidence for a Lower Cretaceous Diversification of Cunninghamioid Cupressaceae

Abstract

Premise of research. The occurrence of six ovulate cones and six leafy branching systems, two of which show attachment of the ovulate cone, reveals a new cunninghamioid fossil conifer from the Cretaceous Apple Bay locality of Vancouver Island, Canada. This anatomically preserved plant expands our understanding of basal Cupressaceae in the fossil record. Methodology. Specimens were studied from anatomical sections prepared by the classic cellulose acetate peel technique. Pivotal results. Vegetative shoots have helically arranged Cunninghamia-like leaves with a single vascular bundle and one to three resin canals. Ovulate cones consist of numerous helically arranged bract/scale complexes with a large bract and a small ovuliferous scale with three separate tips. There are three inverted seeds/ovules attached adaxially, immediately proximal to the free scale tips. Conclusions. This discovery reveals the presence of a new genus and species of basal Cupressaceae, Hubbardiastrobus cunninghamioides, in the Early Cretaceous (Valanginian; ∼136 Ma) of the Northern Hemisphere. These data expand the species richness of fossil Cupressaceae and further document the Cretaceous evolutionary radiation of subfamily Cunninghamioideae.