DNA barcoding and phylogenetics of Ramicrusta and Incendia gen. nov., two early diverging lineages of the Peyssonneliaceae (Rhodophyta)

Secondary pit-connections were previously known from only two species in a single genus of the Peyssonneliaceae, Ramicrusta nanhaiensis and Ramicrusta textilis. However, during ongoing surveys for representative Peyssonneliaceae in Australia and Vanuatu, we uncovered a diversity of peyssonnelioid collections that displayed this anatomical feature. We combined DNA barcoding, using the COI-5P mitochondrial marker to recognize genetic species groups and assign replicate samples to those same groups, with traditional anatomical observations to characterize 11 distinct species with secondary pit-connections. A diverse sampling of the genetic groups was included in molecular phylogenetic analyses using rbcL, EF2 and COI-5P individually and in various combinations to resolve the evolutionary affinities of these species among other Peyssonneliaceae. Our results indicated that peyssonnelioid species with secondary pit-connections resolved in two distinct lineages, necessitating description of Incendia gen. nov. for six new species from Vanuatu Incendia crenata sp. nov., Incendia regularis sp. nov., Incendia cryptotricha sp. nov., Incendia glabra sp. nov., Incendia basilii sp. nov. and Incendia undulata sp. nov. We additionally expand Ramicrusta, recognizing five species from Vanuatu, Ramicrusta textilis, Ramicrusta lateralis sp. nov., Ramicrusta appressa sp. nov., Ramicrusta trichaurea sp. nov. and Ramicrusta aranea sp. nov., one from southern Australia, Ramicrusta australica sp. nov. and one from New Guinea, Ramicrusta calcea comb. nov.