Colaconema ophioglossum comb. nov. and Liagorophila endophytica (Acrochaetiaceae, Rhodophyta) in the eastern Atlantic

Abstract

Two species of acrochaetioid algae (Rhodophyta) are reported from the Canary Islands for the first time. Both Colaconema ophioglossum comb. nov.,previously known from North Carolina and Puerto Rico in the Western Atlantic [as Audouinella ophioglossa Schneider and Acrochaetium ophioglossum (Schneider) Ballantine et Aponte], and Liagorophila endophytica Yamada,cited from several localities in the Pacific Ocean and with a single report from the Caribbean coast of Colombia,constitute new records for the eastern Atlantic Ocean. Colaconema ophioglossum was found growing epi-endophytically between the cortical fascicles of the recently described Canarian endemic Dudresnaya multiramosa Afonso-Carrillo,Sansón et Reyes,which constitutes a new host for this species. Its vegetative cells contain a single lobate parietal chloroplast with a single pyrenoid,a feature exclusive of Colaconema, and consequently the species is transferred to this genus. Liagorophila endophytica was discovered in the outer cortex of Liagora canariensis Børgesen. Data concerning geographical distribution and observations on vegetative and reproductive morphology,especially the development of the carposporophyte,are presented for the two species. In C. ophioglossum,the fertilized carpogonium divides transversely and gonimoblasts are monopodially branched. In L. endophytica the fertilized carpogonium divides longitudinally and the gonimoblasts are radially produced by successive longitudinal cells divisions. This distinctive type of gonimoblast development is regarded as a taxonomically significant feature,and suggests retention of Liagorophila as a separate genus. Conflicting reports of plastid morphology do not allow confident ordinal placement of Liagorophila and the genus is regarded as of uncertain affinity,but allied to the Acrochaetiales or Colaconematales