Fruits of Sabia (Sabiaceae) from the Miocene of western North America and their biogeographic significance.

Distinctive, reticulately sculptured ellipsoidal endocarp impressions have been discovered in Middle Miocene lake deposits of Idaho and eastern Oregon in the northwestern USA. We describe a new species based on these endocarp impressions and compare them morphologically with previously described extinct and extant species of Sabia (Sabiaceae) using light microscopy and micro-CT scanning. Sabia megacarpa sp. nov. endocarps are distinguished by their large size but resemble other species of Sabia in their asymmetric elliptical shape, reticulate surface ribs, unilocular morphology and gland-dotted endocarp surface. Although Sabia is now native to Southeast Asia and Malesia, the fossil record indicates this genus was formerly present in Europe and North America. The new species indicates that Sabia survived until at least 16 million years ago in western North America. [ABSTRACT FROM AUTHOR]