SUAVITAS IMBRICATA GEN ET SP-NOV, AN ANATOMICALLY PRESERVED SEED ANALOG OF PUTATIVE LYCOPHYTE AFFINITIES FROM UPPER PENNSYLVANIAN MARINE DEPOSITS

A megasporangiate fructification has been discovered in dysoxic, offsh ore marine shales from Upper Pennsylvanian deposits of northcentral Te xas. This specimen, described as Suavitas imbricata gen. et sp. nov., consists of imbricating, helically arranged sporophylls that diverge f rom a stout axis. The axis is characterized by parenchymatous pith and weakly developed vascular tissue. Sporangia are terminal with a horiz ontally elongated, apical dehiscence slit. There is one large function al megaspore in each sporangium, and the megaspore wall is constructed of interconnected rodlets. Parsimony analysis indicates that Suavitas may be related to rhizomorphic lycophytes. The unique combination of characters displayed by this species illustrates the central role play ed by extinct species in characterizing overall patterns of plant rela tionships, and emphasizes the uniqueness of plant communities from ext rabasinal habitats during the late Paleozoic.