PREMISE OF THE STUDY: Noeggerathiales are an extinct group of heterosporous shrubs and trees that were widespread and diverse during the Pennsylvanian–
Permian Epochs (323–252 Ma) but are of controversial taxonomic affi nity. Groups proposed as close relatives include leptosporangiate ferns, sphenopsids,
progymnosperms, or the extant eusporangiate fern Tmesipteris . Previously identifi ed noeggerathialeans lacked anatomical preservation, limiting taxonomic
comparisons to their external morphology and spore structure. We here document from the upper Permian of China the fi rst anatomically preserved
noeggerathialeans, which enhance the perceived distinctiveness of the group and better indicate its systematic affi nity.
METHODS: We describe in detail the newly discovered, anatomically preserved heterosporous strobilus Dorsalistachya quadrisegmentorum , gen. et sp. nov.,
and redescribe its suspected foliar correlate, the pinnate leaf Plagiozamites oblongifolius .
KEY RESULTS: Plagiozamites possesses an omega ( Ω )-shaped vascular trace and prominent cortical secretory cavities—a distinctive anatomical organization
that is echoed in the newly discovered strobili. Dorsalistachya strobili bear highly dissected sporophylls alternately in two vertical rows, suggesting
that they are homologs of leaf pinnae. If so, the “strobilus” is strictly a pseudostrobilus and consists of sporangium-bearing units that are one hierarchical
level below true sporophylls. The “sporophylls” bear four microsporangia on the lower (abaxial) surface, occasionally interspersed with short longitudinal
rows of megasporangia. A single functional megaspore develops within each winged megasporangium, suggesting adaptation for dispersal as a
single unit.
CONCLUSIONS: Dorsalistachya presents a unique combination of reproductive features that amply justifi es establishment of a new family, Dorsalistachyaceae. Noeggerathiales
represent a distinct taxonomic Order of free-sporing plants that most resembles early-divergent eusporangiate ferns and the more derived among the
extinct progymnosperms. By the early Permian, noeggerathialeans had attained levels of reproductive sophistication similar to the most derived among the Paleozoic
sphenophytes and lycophytes, but their heterosporous life history may have contributed to their extinction during the Triassic climatic aridifi cation.