Phylogenomic analysis of pseudocryptic diversity reveals the new genus Deltalsia (Rhodomelaceae, Rhodophyta)

Abstract

Molecular analyses, in combination with morphological studies, provide invaluable tools for delineating red algal taxa. However, molecular datasets are incomplete and taxonomic revisions are often required once additional species or populations are sequenced. The small red alga Conferva parasitica was described from the British Isles in 1762 and then reported from other parts of Europe. Conferva parasitica was traditionally included in the genus Pterosiphonia (type species P. cloiophylla in Schmitz and Falkenberg 1897), based on its morphological characters, and later transferred to Symphyocladia and finally to Symphyocladiella using molecular data from an Iberian specimen. However, although morphological differences have been observed between specimens of Symphyocladiella parasitica from northern and southern Europe they have yet to be investigated in a phylogenetic context. In this study, we collected specimens from both regions, studied their morphology and analyzed rbcL and cox1 DNA sequences. We determined the phylogenetic position of a British specimen using a phylogenomic approach based on mitochondrial and plastid genomes. Northern and southern European populations attributed to S. parasitica represent different species. Symphyocladiella arecina sp. nov. is proposed for specimens from southern Europe, but British specimens were resolved as a distant sister lineage to the morphologically distinctive Amplisiphonia, so we propose the new genus Deltalsia for this species. Our study highlights the relevance of using materials collected close to the type localities for taxonomic reassessments, and showcases the utility of genome‐based phylogenies for resolving classification issues in the red algae.

Molecular analyses of turf algae reveal a new species and an undetected introduction in the Pterosiphonieae (Rhodomelaceae, Rhodophyta)

“…Beyond the systematics of the studied species, our work provides further evidence of the utility of phylogenomic approaches for resolving classification issues at various taxonomic levels (Costa et al, 2016; Díaz‐Tapia, Maggs, et al, 2017; Díaz‐Tapia, Pasella, et al 2019; Díaz‐Tapia, Rodríguez‐Buján, et al, 2022; Lyra et al, 2021). The topology of the rbc L and plastid genomes trees (Figure S1 vs.…”

“…phylogenomic approaches for resolving classification issues at various taxonomic levels (Costa et al, 2016;Díaz-Tapia, Pasella, et al 2019;Díaz-Tapia, Rodríguez-Buján, et al, 2022;Lyra et al, 2021). The topology of the rbcL and plastid genomes trees (Figure S1 vs.…”

“…To determine if any of the studied species could have been introduced by human activities on the European or Australian coasts, we have studied the biogeographic distribution of Pterosiphonieae lineages. Phylogenies in this group are challenging when based on one or a few molecular markers, so we have used a phylogenomic approach that has been proven useful to address this problem in the red algae (Costa et al, 2016; Díaz‐Tapia, Maggs, et al, 2017; Díaz‐Tapia, Pasella et al, 2019; Díaz‐Tapia, Rodríguez‐Buján, et al, 2022; Lyra et al, 2021).…”

On the track of unknown algae

“…As reported in this issue of the Journal of Phycology , Díaz‐Tapia and Verbruggen (2024) have carried out an extensive study of the biodiversity of turf‐forming red algae. Turfs are of particular interest in the context of global change, as they are globally seen to replace stands of larger canopy‐forming algae (Filbee‐Dexter & Wernberg, 2018).…”

“…Now, in this issue of the Journal of Phycology , Díaz‐Tapia and Verbruggen (2024) have provided the taxonomic and nomenclatural conclusions of their analyses. Struck et al.…”