Lauraceous flowers from the Late Cretaceous of North Carolina, U.S.A.

Abstract

Three new taxa with clear affinity to extant Lauraceae are described from the Santonian/Campanian (c.83 Myr, Late Cretaceous) Neuse River locality in North Carolina, U.S.A. A new lauraceous genus, Neusenia, is established to accommodate an excellently preserved flower with tetrasporangiate anthers and psilate pollen grains. Two additional lauraceous taxa are described but not named due to incomplete preservation. The fossil taxa described in this paper represent a variety of evolutionary lineages within Lauraceae with respect to inflorescence structure and anther morphology, including both distinctly pedicellate flowers and sessile, closely crowded flowers, as well as tetrasporangiate and disporangiate anthers. In light of the co-occurrence of both tetrasporangiate and disporangiate anthers in the Neuse River flora, the plesiomorphic state of lauraceous anthers is discussed. Mapped on a recent cladogram of Laurales, tetrasporangiate anthers appear to be primitive within Lauraceae. Thus, disporangiate 2-valvate anthers must have evolved independently at least three times in Laurales (in Lauraceae, Hernandiaceae, and Atherosperrnataceae/Gomortegaceae). In Hernandiaceae and Atherosperrnataceae/Gomortegaceae such anthers are interpreted to have originated from tetrasporangiate 2-valvate anthers through reduction of the septum in each theca, while in Lauraceae they may have originated in the same way and/or from reduction of two pollen sacs in a tetrasporangiate 4-valvate anther.