A new interpretation of the Jurassic seed cone Pararaucaria patagonica

ROTHWELL, GAR; ESCAPA, IGNACIO; STOCKEY, RUTH; CÚNEO, RUBÉN

Columbus, Ohio

Congreso; Botany 2012; 2012

The genus Pararaucaria was erected by for permineralized seed cones from the historic Jurassic Cerro Cuadrado Petrified Forest in Santa Cruz Province, southern Argentina (Patagonia). Pararaucaria has been systematically linked to several conifer families including Araucariaceae, Cheirolepidiaceae, Pinaceae, Taxodiaceae, and Voltziaceae, while other authors have suggested that P. patagonica represents a distinct conifer family. A reexamination of both previously described and newly studied specimens reveals previously unknown systematically informative characters (e.g., distal scale lobes) and allows for new homology interpretations of previously described tissues (e.g., putative seed wings). Together, these newly interpreted characters demonstrate that Pararaucaria represents the conifer family Cheirolepidiaceae, thus providing The first anatomical information for seed cones of this important Mesozoic conifer clade. Newly developed information also emphasizes the dependence of conifer taxonomy on homology hypotheses, and on structural interpretations of the different seed cone structures.