Discovery of Flabellia petiolata (Halimedaceae, Chlorophyta) in the southern British Isles: A relict population or a new introduction?

Historical biogeographical analysis of the Udoteaceae (Bryopsidales, Chlorophyta) elucidates origins of high species diversity in the Central Indo-Pacific, Western Indian Ocean and Greater Caribbean regions

“…The group is distributed worldwide, in tropical to warm temperate seas, including the tropical Atlantic, Indian and Pacific Oceans, as well as in the Mediterranean and Red Sea. Some genera are widely distributed, spanning different oceans, while others are more range-restricted, such as Rhipocephalus, which only occurs in the tropical western Atlantic (Littler and Littler, 2003) or Flabellia, which is only found in the Mediterranean Sea and northeastern Atlantic (Díaz-Tapia et al, 2020b). Next to a high diversity in the Indo-Pacific, species diversity in the Udoteaceae is particularly high in the Greater Caribbean region (Bermuda, Bahamas, Florida, Gulf of Mexico and Caribbean sensu stricto).…”

Genetic Diversity and Phylogeography of a Turf-Forming Cosmopolitan Marine Alga, Gelidium crinale (Gelidiales, Rhodo-Phyta)

“…One notable result is a continuous distribution of haplotype C1 from the Eastern Atlantic (England, northern France, and Spain) to the Mediterranean Sea (southern France, Italy, and Slovenia), suggesting northern expansion from the warm Mediterranean population because G. crinale occurs more commonly in warm waters than cold waters. However, a disjunct distribution of Flabellia petiolata (Turra) Nizamuddin, a green alga in Halimedaceae, between southern England and the Mediterranean Sea, is considered a relict population that once occurred probably during warmer periods (about 11,700 years ago) [ 31 ].…”

Non-indigenous seaweeds in the Northeast Atlantic Ocean, the Mediterranean Sea and Macaronesia: a critical synthesis of diversity, spatial and temporal patterns

“…Eventually, the possibility of introductions needs to be evaluated against historic and ongoing natural dispersal events. The recent observation of Flabellia petiolata from the south coast of England confronts researchers with exactly this question (Díaz-Tapia et al, 2020). Despite a long tradition of seaweed studies and regular surveys, F. petiolata was never recorded from the British Isles prior to 2013.…”