FOSSIL ERICALES FROM THE UPPER CRETACEOUS OF NEW JERSEY

Premise of research. Fossil flowers and other related organs of Turonian age from Cretaceous Atlantic Coastal Plain deposits in northern New Jersey are remarkable in their degree of preservation and document important events in the radiation of eudicot angiosperms relatively early in their history. Methodology. Fossils isolated from silty clays have been examined with light microscopy, TEM, SEM, and micro-CT scan to illuminate their structural details. Fossil characters were placed in data matrices that included morphological and molecular genetic characters to place them phylogenetically in order to test the hypothesis that they are extinct representatives of the modern Ericales. Pivotal results. These fossils represent a clade of three species and include flowers, inflorescences, and leaves, constituting a genus that is unique relative to existing angiosperm genera but that nonetheless shares a significant number of characters with living families placed in the broader Ericales (APG III) including Ericaceae. Fossils representing this taxon include dispersed individual flowers, inflorescences, fruits, and leaves. Conclusions. These fossils are interpreted as representing a complex of at least three closely related ericalean species because of common morphological characters, including those shared by the flowers and fruits. These include five-merous, haplostemonous, hypogynous flowers; staminodes opposite the clawed petals; distinctive sessile abaxial sepal glands; papillate ovaries; five-lobed capitate stigmas; and numerous reticulate seeds in valvate loculicidal capsules. Variation among the three species as delimited here includes trichome form and distribution. Based on morphological cladistic analyses, the fossils are placed within Ericales near modern Clethraceae and Cyrillaceae, outside of but close to the clade of extant (core) Ericaceae. The flower fossils have some interesting characteristics suggestive of well-developed relationships with pollinating insects, including, in one of the species, pollen grains united by fine threads (interpreted as viscin threads) and anther spurs often associated with hymenopteran pollination in modern taxa.