Dictyota falklandica sp. nov. (Dictyotales, Phaeophyceae) from the Falkland Islands and southernmost South America

Abstract

Surveys of the seaweed flora of the Falkland Islands and of Tierra del Fuego revealed the presence of a new species of brown alga. Dictyota falklandica sp. nov. inhabits the shallow rocky infralittoral in sheltered localities and the lower intertidal in more exposed sites. Dictyota falklandica has a regular to irregular habit of dichotomously branched blades, forming erect thalli composed of a single-layered cortex and medulla, with margins in the apical parts dotted with dormant apical cells. Sporangia occur in irregular groups or longitudinal lines on the thallus surface. Molecular phylogenies based on chloroplast psbA and rbcL and mitochondrial cox1 sequences showed that the species from the Falkland Islands is sister to a clade formed by D. korowai, recently described from New Zealand and D. kunthii known from both the Pacific coast of South America and New Zealand. Temperature tolerance experiments, showing mortality at 25°C but survival at 20°C, confirm the cold-temperate affinity of this taxon. Its relationship to other cold-temperate Southern Hemisphere species is discussed, with its closest relatives living in regions with sea surface temperatures of at least 7-10°C higher.

Fucoxanthin and Phenolic Contents of Six Dictyotales From the Tunisian Coasts With an Emphasis for a Green Extraction Using a Supercritical CO2 Method

“…The genus Dictyota showed significant differences in the PCA (Figures 3, 4), particularly between Dictyota spiralis and Dictyota fasciola (formerly Dilophus genus) on the one side and D. dichotoma on the other side. Hörnig et al (1992) merged Dilophus genus in Dictyota, based on morphological features; however, recent phylogenetic results presented by Küpper et al (2019) argued in favor of a genus Dilophus, distinct from Dictyota. At the chemical level, since considerable variation has been observed between samples from the same Dictyota species taken at different localities and during different seasons, it is not possible to draw conclusions whether the chemical content is species-specific (Bogaert et al, 2020), though as fucoxanthin and polyphenols are dependent on environmental conditions including light exposure, the difference in their concentrations in closely related species might be due to differences among habitats (Heriyanto et al, 2017).…”

Global biogeography and diversification of a group of brown seaweeds (Phaeophyceae) driven by clade‐specific evolutionary processes

“…This study focuses on the biogeographical history and diversification of Dictyotales, one of the most diverse orders of brown algae (Bringloe et al., 2020). Unlike most other brown algal groups, Dictyotales form an important component of both temperate and tropical benthic marine floras (Küpper et al., 2019; Tronholm, Steen et al., 2010), making it an excellent case study for improving our understanding of latitudinal diversity patterns and the factors underlying diversification. Recent molecular phylogenies of the genera Dictyota , Padina and Lobophora (Silberfeld et al., 2014; Tronholm, Steen et al., 2010; Vieira et al., 2017) revealed rampant cryptic diversity as well as high species diversity.…”

Hidden in plain sight: Lindauera gen. nov.: a new genus of Dictyotales from New Zealand

“…The order Dictyotales is diverse and speciose (Bringloe et al . 2020), with peak diversity found in the tropical Indo-Pacific, and Australasia (Küpper et al 2019). There is a single family and two tribes recognised in the order; members of the Dictyoteae have a single apical cell, whereas members of the Zonarieae are characterised by having many localised or marginal apical cells.…”