The morphology of Catenellopsis (Catenellopsidaceae, fam. nov.; Rhodophycota)

Abstract

Catenellopsis oligarthra, a small caespitose red alga endemic to New Zealand, is currently classified with the Gymnophloeaceae (Gigartinales), but it exhibits patterns of vegetative and reproductive morphology previously unknown in the Rhodophycota that suggest the removal of Catenellopsis to a new monotypic family. The plants originate from a basal pulvinus that includes rhizoidal and other secondary filaments. Numerous erect triaxial reproductive branches that lack any capacity for secondary development arise from individual filaments of the pulvinus. Gametophytic branches develop a single constriction, within which superficial cells fuse to form a reticulum that gives rise to an external annulus composed of catenate sporangia. Cruciate tetrasporangia are transformed from terminal cells throughout the cortex of unconstricted tetrasporophytes.