A preliminary study on life history of Erythrotrichia bohanensis (Erythropeltales, Rhodophyta)

Erythrotrichia bohanensis Huang, Chu et Ding is a recently reported new species, with the type specimen originating from Qinhuangdao, China. Being a lower filamentous red alga, it lives an epiphytic life. In this study, E. bohanensis was isolated from red and brown macroalgae collected in Qinhuangdao, Hebei, in spring 2023. They were cultured under laboratory conditions, and their life cycle was an alternation of sporophyte and gametophyte generations. Thalli are monoecious, with mature gametophytes producing carpogonia and spermatangia. Spermatangia release spermatia through “post-maturation” (maturation after detachment from the thallus) and “over-maturation” (maturation within the thallus). Fertilization occurs between sperms and ova outside the thallus or on the thallus surface, and the zygote germinates to form the sporophyte. Mature sporophytes release monospores, which germinate into gametophytes outside the thallus. This study first reports the life cycle of the new species E. bohanensis, supplementing the sexual reproductive structures and early life history pathways of the genus Erythrotrichia. It also enriches understanding of the diverse reproductive strategies and life history processes that characterize the adaptive capabilities of lower marine red algae to their environments.