"Leaf fossils of "Ziziphus" fibrillosus were for a while incorrectly classified in the pepper family Piperaceae, and therefore thought to be a climber or herb. It is since been tentatively returned to the buckthorn family, but not as a true Ziziphus."

― Saurian encylopedia

"Ziziphus" fibrillosus belongs to the buckthorn family Rhamnaceae. Just like the name suggests, many members of the buckthorn family have thorns, and this could be true in the "Ziziphus" as well. One modern member of the family, the jujube, produces a brown-red berry that is commonly used as a food source.