Paralycopodites Morey & Morey, From the Carboniferous of Euramerica—a Reassessment of Generic Affinities and Evolution of “Lepidodendron” Brevifolium Williamson

A study of the morphologies and evolutionary relationships of Upper Carboniferous coal swamp lycopods indicated that plants traditionally treated as Lepidodendron hrevifolium were distinct from Lepidodendron at the generic level, and were not part of a morphological cline between Lepidodendron and Lepidophloios. The description of a new genus and species by Morey and Morey (1977), based on a specimen identical to L. brevifolium distal branches, results in the inclusions of L. brevifolium in Paralycopodites, in which it has nomenclatural priority over P. minutissimus. The small trees or shrubs had deciduous lateral branches and permanently retained leaves; in these characters, Paralycopodites is most similar to the compression‐impression genus Ulodendron as delimited by Thomas. Bisporangiate Lepidostrobus cones are closely associated with the vegetative remains; the cones can be assigned to three stratigraphically complementary species throughout the range of Paralycopodites—Visean to Westphalian D (Middle Pennsylvanian). Extreme evolutionary conservatism is indicated by the low vegetative morphological variability and the great similarities in morphology of associated cones; in combination with the sudden Visean appearance of P. brevifolius and the lack of intermediates among major lycopod genera, this lends support to punctuated equilibria hypotheses. Paralycopodites was generally rare in coal swamps, possibly related to its production of megaspores lacking specialized adaptations for flotation. Its pattern of late Middle Pennsylvanian extinction parallels Lepidodendron and Lepidophloios.