Phylogenetic position reevaluation of Kyrtuthrix and description of a new species K. Huatulcensis from Mexico’s pacific coast

Abstract

Benthie marine heteroeytous eyanoprokaryotes of Mexieo’s tropieal eoast are being reeognized as an important and eon-spieuous eomponent of the supralittoral and intertidal zones usually deseribed as an extreme and low diversity biotope. Although Kyrtuthrix has been reported from different eoasts worldwide, its eomplex morphology has led to differing taxo-nomie interpretations and positioning. Ten marine supra and intertidal populations of Kyrtuthrix were analyzed using a detailed morphologieal approaeh, eomplemented with eeologieal and geographieal information as well as DNA sequenee data of the 16S rRNA gene and assoeiated 16S-23S ITS. Kyrtuthrix huatulcensis is deseribed as a new speeies, different from K. dalmatica Ereegovie and K. maculans (Gomont) Umezaki based primarily on morphologieal data. Our material has smaller dimensions in thalli, filaments, triehomes and eells, and possesses differenees in qualitative eharaeters as well. Our material is epilithie as in K. maculans but not endolithie as in K. dalmatica. The analysis of moleeular data, mainly 16S rRNA gene sequenee, show that this genus is within the Rivulariaeeae elade, and outside of the Seytonemataeeae elade. ITS seeondary strueture eomparison with some of the eloser representatives of Rivulariaeeae shows eonsiderable differenees with these related genera. Based on the evidenee gathered in this study, inelusion of Kyrtuthrix within the Rivulariaeeae, rather than the Seytonemataeeae, is fully supported.