Beardia vancouverensis gen. et sp. nov. (Juglandaceae): permineralized fruits from the Eocene of British Columbia

Abstract

Large numbers of permineralized juglandaceous fruits were identified in calcareous nodules from the Eocene Appian Way locality on Vancouver Island, British Columbia, Canada. The fruits, small dorsiventrally flattened nutlets, 4.5-7.0 mm long and 5.5-9.0 × 3-5 mm in diameter, were studied using cellulose acetate peels. They are wingless, ribbed, and have a lobed epicarp that surrounds the nutlet. Cells of the inner epicarp are thin-walled and traversed by a system of branching vascular strands. The stony nutlet wall is composed of fibers, with an outer layer of distinctive idioblasts. The fruits have a symmetry like that in Juglandaceae, subfamily Juglandoideae, tribe Platycaryeae, while the fibrous nut walls are like those of subfamily Engelhardioideae. This unique combination of characters indicates that these fruits represent a new genus and species of Juglandaceae: Beardia vancouverensis gen. et sp. nov. The excellent preservation of the Appian Way specimens has allowed a unique view of the internal fruit anatomy and external morphology. As the only wingless, flattened nuts known in the family, they further extend the range of morphological variation in fruits in the family. These fossils further support the hypothesis that North America was an important center of generic diversity for Juglandaceae during the early Tertiary.