Phylogenetic systematics of the Gigasporales

The classification, phylogeny, and evolutionary pathways of the Gigasporales are re-evaluated based on concomitant morphological and molecular phylogenetic analyses. Only Cetraspora was not supported in the morphology-based tree, while Quatunica formed a monophyletic group with its sister genus Dentiscutata. Only a few taxa were not completely supported in the SSU rDNA phylogenetic analyses, namely Dentiscutata and Fuscutata (Dentiscutataceae) and Racocetra and Cetraspora (Racocetraceae). However, all trees generated by the LSU, SSU (rDNA), and beta-tubulin genes supported the existence of the families with strong support for all genera represented in the LSU rDNA and beta-tubulin analyses. In conclusion, the current classification of the Gigasporales has a strong morphological and molecular congruency.