The mid-Paleocene fruit and seed flora from the Fort Union Formation of Newell’s Nook, southeastern Montana, USA

The middle Paleocene Newell’s Nook biota of the Tongue River Member Fort Union Formation, southeastern Montana, is best known for its early Tiffanian mammalian fauna. Here, we describe an informative fruit and seed assemblage from this locality. These records refine lower stratigraphic boundary several plant genera more widely paleobotanical localities less certain assignment within upper help to fill a gap in our knowledge about mid-Paleocene floristic composition Rocky Mountain Great Plains region. Recognized taxa belong families Characeae, Taxaceae, Menispermaceae, Sabiaceae, Hamamelidaceae, Cercidiphyllaceae, Vitaceae, Cucurbitaceae Juglandaceae. Several morphotypes remain uncertain as familial position. Based on dispersal syndromes extant relatives, 2/3 these fruits were adaptive animal dispersal, with hard seeds or endocarps covered by fleshy outer layer. Dry nuts likely part diet small mammals. locality presents another rare example North American provides insights dietary habits ecology co-occurring fauna time.