Rariglanda jerseyensis, a new ericalean fossil flower from the late cretaceous of New Jersey

Abstract

A new species, Rariglanda jerseyensis, is described from well-preserved fusainized fossil flowers collected from the Late Cretaceous of New Jersey. Phylogenetic analyses and comparisons with extant and extinct taxa place R. jerseyensis within the monophyletic Ericales, sister to Clethraceae. The most distinctive feature of R. jerseyensis is a dense covering of conspicuous multicellular trichomes on the abaxial surface of the calyx. These multicellular trichomes appear to be glandular, and similar trichomes are found in several other, unrelated, Late Cretaceous fossils. In particular, the ericalean fossil Glandulocalyx upatoiensis bears the most similarity to R. jerseyensis, although differences in androecium and trichome characters clearly separate the two taxa. In addition, phylogenetic analyses confirm the position of G. upatoiensis within the Ericales, but place it within the sarracenioid clade, in a polytomy with Actinidiaceae and Roridulaceae. Past ecological studies associating trichomes with defense against herbivores and pathogens, coupled with the prevalence of multicellular trichomes on flowers among different lineages of fossils in the Cretaceous, suggest that glandular trichomes could have been an important adaptation against herbivore feeding during the Cretaceous.