Upper Cretaceous Conifer Leaf Fossils from the Black Creek Formation with an Assessment of Affinities Using Principal Components Analysis

Abstract

Five types of fossil conifer foliage from the Upper Cretaceous Black Creek Formation of North Carolina have been reexamined from newly discovered material. The cuticular and gross morphology of Androvettia carolinensis, Brachyphyllum squammosum, Brachyphyllum sp., Geinitzia reichenbachii, and Moriconia cyclotoxon is described and illustrated. To determine the affinities of these nonreproductive remains, data for sixteen characters of leaf and cuticle morphology were gathered for the modern conifers and the fossil taxa and analyzed using Principal Components Analysis (PCA). Once characters were identified that caused known family members to sort into correct family groups with PCA, it was assumed that the fossil taxa scored for the same characters would cluster with family groupings, indicating affinities. This analysis indicates that A. carolinensis and Brachyphyllum sp. are members of the Hirmerellaceae and G. reichenbachii and B. squammosum are members of the Araucariaceae. The affinities of M. cyclotoxon are unresolved.