Phylogenetic analyses clearly demonstrate that novel character mosaics of Cretaceous cornaleans play a critical role in resolving deep-node relationships within Cornales. The post-Cretaceous increase of cornalean disparity is associated with a shift in morphospace occupation, which can be explained from ecological and developmental perspectives.

BackgroundCornaceae consists of 58 species, all within the genus Cornus. The Cenozoic record of Cornus is extensive and well documented. Molecular divergence-time studies suggest that crown-group Cornus may have originated by the Late Cretaceous. However, there has been no formal report of Cornus from Cretaceous deposits. Here, we characterize a permineralized fossil fruit assignable to Cornus subg. Cornus from the Upper Cretaceous (Campanian) Shelter Point locality of Vancouver Island, British Columbia, Canada.MethodsSerial sections of the specimen were made using the cellulose acetate peel technique. Peels were mounted onto microscope slides and studied by light microscopy.ResultsThe fossil fruit consists of a tri-locular woody endocarp with dorsal germination valves. The locules are sub-triangular to ellipsoidal in transverse section and are separated by thin septa. Endocarp tissue consists of elongated and isodiametric sclereids and secretory cavities. Internal vascular tissue was not observed, but is interpreted to have been located along the outer periphery of the septa for some length, common in many cornalean taxa. There is one seed in each locule, one of which was found to have endosperm and a dicotyledonous embryo.DiscussionWoody endocarps with germination valves, without central vascular bundles, and with one seed per locule are characteristic of several families within the order Cornales. The interpreted vascular pattern and presence of secretory cavities indicates that the fossil fruit is assignable to Cornus subg. Cornus. Comparative analysis suggests that the fossil is most similar to Cornus piggae, a species described from the Paleocene of North Dakota. This fossil is the first evidence of crown-group Cornaceae from the Cretaceous and sheds light on both the plesiomorphic fruit characters and the timing of the initial diversification of the family and basal asterid lineage, Cornales.

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.

Two permineralized cornalean fruits from the Campanian of the state of Washington in the northwestern United States were studied using the cellulose acetate peel technique. One specimen was reconstructed three-dimensionally using ImageJ software. Fruits are ellipsoidal and consist of valvate endocarps. Valves are restricted to the apical third of the endocarp. Endocarps are tetralocular and each locule is crescent-shaped in cross section. The valve tissue consists of isodiametric sclereids and secretory cavities. Septae are composed of transversely elongated sclereids and secretory cavities. In each septum there are roughly two rows of vascular bundles that extend the length of the fruit. There is one apically attached seed per locule. These fossil fruits display a unique mosaic of characters indicative of Cornaceae, Nyssaceae, Davidiaceae, and Mastixiaceae, but not conforming to any one of these extant families. Therefore, they are assigned to a new genus and species within Cornales, Suciacarpa starrii gen. et sp. nov. The novel combination of characters of Suciacarpa sheds light on the early evolution of Cornales and supports previous phylogenetic hypotheses.Key words: Cornales, Cornus, Cretaceous, Davidia, fossils.Résumé : Deux cornouilles perminéralisées du Campanien de l'état de Washington dans le nord-ouest des Etats-Unis ont été étudiées à l'aide de la technique de pelliculation à l'acétate de cellulose. Un spécimen a été reconstruit en trois dimensions par le logiciel ImageJ. Les fruits sont ellipsoïdaux et consistent en endocarpes valvés. Les valves sont restreintes au tiers apical de l'endocarpe. Les endocarpes sont tétra-loculaires et chaque loge a la forme d'un croissant en coupe transversale. Le tissu de la valve consiste en sclérites isodiamétriques et en cavités sécrétoires. Les cloisons sont composées de sclérites transversalement allongées et en cavités sécrétoires. Dans chaque cloison se trouvent à peu près deux rangées de faisceaux vasculaires qui prolongent la longueur du fruit. On trouve une graine par loge attachée à l'apex. Ces fruits fossiles présentent une mosaïque unique de caractères représentatifs des Cornaceae, Nyssaceae, Davidiaceae et Mastixiaceae, mais qui ne se conforment à aucunes de ces familles existantes. Ainsi, ils sont assignés à un nouveau genre et espèce à l'intérieur des Cornales, Suciacarpa starrii gen. et sp. nov. Cette combinaison inédite de caractères de Suciacarpa fait la lumière sur l'évolution précoce des Cornales, et corrobore les hypothèses phylogéné-tiques précédentes. [Traduit par la Rédaction]

The unique combination of characters shown by these fruits is found in Cornaceae, Curtisiaceae, and Davidiaceae and allows us to describe a new taxon of Cornales, Eydeia hokkaidoensis gen. et sp. nov., with many similarities to extant Davidia involucrata. These fossils underscore the phylogenetic diversification of Cornales that was underway during the Late Cretaceous and support the hypothesis that a Davidia-like fruit morphology is plesiomorphic within Cornales.

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This study documents a new extinct species of cunninghamioid conifers, Hughmillerites vancouverensis, expanding the record of the genus from the Late Jurassic to the Early Cretaceous. This new extinct species emphasizes the important role that conifers from subfamily Cunninghamioideae played in the initial evolutionary radiation of Cupressaceae. In light of recent findings in conifer regulatory genetics, we use H. vancouverensis to hypothesize that variations of expression in certain gene homologues played an important role in the evolution of the cupressaceous ovuliferous scale.