New fossil leaves of Araceae from the Late Cretaceous and Paleogene of western North America

Abstract

The fossil record of Araceae is expanded by three new leaf species from the Upper Cretaceous and Paleogene of North America: 1) Orontium wolfei BOGNER, K. JOHNSON, KVACEK & UPCHURCH sp. nov. (Lower–Middle Eocene, northern Washington and southern British Columbia); 2) Orontium mackii BOGNER, K. JOHNSON, KVACEK & UPCHURCH sp. nov. (Maastrichtian, New Mexico); and 3) Symplocarpus hoffmaniae BOGNER, K. JOHNSON, KVACEK & UPCHURCH sp. nov. (uppermost Maastrichtian of North Dakota and lowermost Paleocene of Colorado). A fourth representative of Orontioideae, Lysichiton austriacus (J. KVACEK & A.B. HERMAN ) BOGNER, K. JOHNSON, KVACEK & UPCHURCH comb. nov., is based on a leaf fossil described from the lower Campanian of Grunbach, Austria, central Europe, and its name is re-combined herein from Araciphyllites. All species can be assigned to Araceae, subfamily Orontioideae, based on their distinctive patterns of venation, which are directly comparable to those of extant genera. This indicates that the Orontioideae originated sometime during the Cretaceous, and that the lineages related to extant genera were present by the Campanian-Maastrichtian. Climatic analysis of associated leaf assemblages indicates that the thermal tolerances of fossil Orontioideae mostly fall within the range of living representatives.