¿Cretaceous Montiaceae? Reevaluation of the classification of Kuprianovaites deccanensis Nambudiri & Thomas (Caryophyllales)

Kuprianovaites deccanensis Nambudiri & Thomas is a form species referring to fossil ovule/seed-bearing fructifications from the Cretaceous/Paleocene boundary of central India. It has been classified in Montiaceae based on similarities to fruits of Phemeranthus Raf. species, in particular a 3- valvate unilocular loculicidal capsule with free-central placentation and seeds with campylotropous ovules. Kuprianovaites is likewise similar to fruits of Talinum species (Talinaceae), but differs in lacking a conspicuously two-layered pericarp. At the same time, however, available seed images of Kuprianovaites show no evidence of an investing aril (pellicle) characteristic of Phemeranthus species. Lacking a clear synapomorphy with either Talinaceae or Montiaceae, the morphological and geographical evidence suggest that Kuprianovaites is better assigned to the Portulacineae stem group. This classification accords better with current molecular-based divergence estimates. The implications for Portulacineae historical biogeographic interpretation are discussed.