An overview of bladed Bangiales (Rhodophyta) from the Levantine basin in the eastern Mediterranean Sea, with the first record of Neopyropia elongata from the Israeli intertidal

Compared to other marine eco-regions, the Levantine basin in the eastern Mediterranean Sea is characterized by elevated average temperatures, salinities and solar radiation. Such conditions coupled with ongoing climate changes pose a bleak future for the native marine biota, particularly for species already at the limits of their upper temperature tolerance. In the Israeli Mediterranean Sea, the diversity of marine macroalgae is estimated to be approximately 300 species, a number similar to neighbouring countries within the Levantine basin. In the Israeli Mediterranean Sea, an annual bladed Bangiales herein Porphyra sensu lato (s.l.), typically thrives in the rocky intertidal zone during late winter-early spring. Despite its unique prevalence and distinct seasonality, the exact taxonomic status of this species is unclear. Furthermore, based on morphological features of specimens collected over time, we have speculated that there might be more than one species present on local shores. Hence, we aimed to clarify the taxonomic identity of this Porphyra s.l. within the Israeli Mediterranean Sea and subsequently determine its relationship with other bladed Bangiales species within the Levantine basin. We analysed 16 DNA samples from morphologically distinct specimens collected between 2007 and 2021, and constructed phylogenetic trees for rbcL, COI, ITS1 and SSU molecular markers. Our results revealed that all samples examined belonged to a previously defined ‘Porphyra leucosticta complex’, specifically to the cryptic species Porphyra rosengurttii, a current synonym of the newly accepted name Neopyropia elongata. GenBank data mining and a literature review suggested five bladed Bangiales taxa in the Levantine basin, namely Neopyropia leucosticta, Porphyra atropurpurea, N. koreana, P. umbilicalis and P. linearis, but their precise taxonomic identification is unconfirmed, pending molecular and morphological studies.