J. Rice et al., SUAVITAS IMBRICATA GEN ET SP-NOV, AN ANATOMICALLY PRESERVED SEED ANALOG OF PUTATIVE LYCOPHYTE AFFINITIES FROM UPPER PENNSYLVANIAN MARINE DEPOSITS, American journal of botany, 83(8), 1996, pp. 1083-1090
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.