Confirmation that Antevsia zeilleri microsporangiate organs associated with latest Triassic Lepidopteris ottonis (Peltaspermales) leaves produced Cycadopites-Monosulcites-Chasmatosporites- and Ricciisporites-type monosulcate pollen

Abstract

In reply to the commentary by N. Zavialova (Rev. Palaeobot. Palynol. 322, 105,065), we provide additional data and illustrations reaffirming that the Triassic peltaspermalean ‘seed-fern’ Lepidopteris ottonis produced the abnormal pollen Ricciisporites tuberculatus, solving a long-standing mystery in palaeobotany. The microsporangiate organ Antevsia zeilleri linked to Lepidopteris ottonis foliage produced polymorphic pollen ranging from smooth-walled monads that would normally be attributed to Cycadopites, Monosulcites and Chasmatosporites to strongly ornamented Ricciisporites tuberculatus-type grains occurring in permanent tetrads. Multiple microscopy techniques reveal that these in situ and associated dispersed pollen are represented by a complete continuum in exine ornamentation. Moreover, scanning electron microscopy and ultrastructural analyses reveal variation in the wall architecture between these pollen types that can be explained by aberrant developmental pathways within the pollen sac. Finally, the occurrence of Ricciisporites tuberculatus in at least 15 Antevsia zeilleri sacs and their co-occurrence with smooth-walled monosulcate pollen in an additional five pollen sacs, in the absence of any other palynomorphs, plant detritus or mineral matter, demonstrates their co-production by the parent plant and excludes the possibility of taphonomic mixing.