Phylogeography of the Red Algal Laurencia Complex in the Macaronesia Region and Nearby Coastal Areas: Recent Advances and Future Perspectives

Abstract

Since the conception of the genus Laurencia by Lamouroux in 1813, several red macroalgal species have been included in it. In recent decades, the development of modern molecular tools has resulted in multiple taxonomic modifications, and presently, eight related genera are recognized in the so-called Laurencia complex. In the Macaronesian Region (Central East Atlantic Ocean), species from the Laurencia complex are keystone elements of the benthic communities, especially in the intertidal zone. In this review, we consolidate the existing knowledge about the Laurencia complex within the Macaronesian archipelagos and nearby areas. Morphological descriptions and phylogeographic remarks of the 16 currently accepted species-whose records were molecular or morphologically confirmed-are included together with an identification key for the Macaronesian Region. The phylogeographic data allowed us to re-visit the role of the Macaronesian archipelagos as a bridge area for the marine flora of the Mediterranean and Caribbean Seas (remnants of the former Thetyan Sea) or contemplate their marine flora as the result of successive processes of recolonization after the Quaternary glaciations from those donor areas. Finally, some comments about the frontiers of the research in the Laurencia complex in the Macaronesian Region and nearby coastal areas are included.

Restructuring of the ‘Macaronesia’ biogeographic unit: A marine multi-taxon biogeographical approach

“…A number of studies based on marine coastal fishes and gastropods from Cabo Verde concluded that the community structure and biogeographic relationships of its marine biota differ significantly from the other Macaronesian archipelagos 5,8,46–55 .…”

Melanothamnus macaronesicus Rodríguez-Buján & Díaz-Tapia, sp. nov. (Rhodomelaceae, Rhodophyta): A New Turf-Forming Species from the Azores and the Canary Islands

“…failed to detect this taxon. Likewise, the new species was not found in molecular diversity surveys of this group in Central American coasts (Stuerke & Freshwater 2008, 2010Mamoozadeh & Freshwater 2011, even if this region and Macaronesia often share the occurrence of species (Haroun & Prud'homme van Reine 1993;Machín-Sánchez et al 2018). While we cannot rule out that the new species could have remained unnoticed in these or other undersampled regions (e.g.…”

Validated Inventories of Non-Indigenous Species (NIS) for the Mediterranean Sea as Tools for Regional Policy and Patterns of NIS Spread

“…Out of 65 data deficient species 12 were macroalgae, whose alien status is debated among experts due to complexities in taxonomic identification, the existence of species complexes (e.g., the Laurencia complex [94,95]) or the possibility of Tethyan relicts (e.g., Acanthophora nayadiformis and Spyridia aculeata [96]). On the other hand, one characteristic example of a macroalgal species which was revised in the current inventory is Halophila decipiens.…”