Winged fruits of Pteleoidea gen. nov. from the Paleocene of Wyoming, USA

Winged fruits formerly attributed to Koelreuteria from the Paleocene Fort Union Formation of southwestern Wyoming are reevaluated. Numerous additional specimens have been collected to supplement the original treatment of K. annosa Brown, which was based on only one specimen. Differences from extant and fossil species of Koelreuteria lead us to recognize a new genus. Pteleoidea annosa (Brown) gen. et comb. nov. is characterized by elliptical fruits with a pair of wings lying in a common plane, with an apical style and borne on a long, narrow pedicel. The fruit possesses a hypogynous nectary disk and perianth. The central fusiform locular region sometimes preserves elongate elliptical seeds, borne in axile attachment. Although the fruits do not conform precisely to an extant genus, sapindalean affinity, possibly with the Rutaceae, is suggested. Glanddotted serrate leaflets found in association with the fruits are also inferred to be of sapindalean affinity. These remains add to the diversity of extinct eudicots encountered in the Paleocene of North America.