Laurencia, IN

Popolizio, Thea R., Schneider, Craig W., Jongbloed, Walter M., Saunders, Gary W. & Lane, Christopher E., 2022, Molecular analysis resolves the taxonomy of the Laurencia complex (Rhodomelaceae, Ceramiales) in Bermuda and uncovers novel species of Chondrophycus and Laurenciella, Cryptogamie, Algologie 20 (1), pp. 1-30 : 10-12

THE GENUS LAURENCIA IN BERMUDA

COI-5P and rbc L sequence data support the recognition of two species for collections long called Laurencia obtusa in Bermuda, both of which are distantly related to true L. obtusa from Europe. These species represent examples of western Atlantic entities with a misassigned European binomial placed upon them by phycologists of the 19th and early 20th centuries (see Popolizio et al. 2013). The rbc L barcode gap analysis presents support for the conspecificity of Bermuda specimens with Laurencia dendroidea and L. catarinensis from Brazil ( Cassano et al. 2012a; Machín-Sánchez et al. 2012). Intraspecific divergences in rbc L for the two are 0.5% and 0.3%, respectively, compared with interspecific divergences of 5.5% and 3.7% ( Table 1). These species herein represent new reports for Bermuda. Our collections of these two species had previously been assigned to L. obtusa , but our molecular data suggest L. obtusa is not found in Bermuda and likewise may not be present in the tropical western Atlantic. These data also show that both species are present in the Florida Keys and St. Croix

Mateo-Cid, Mendoza-Gonzalez, Sentíes & Díaz-Larrea and L. venusta Yamada.

in the US Virgin Islands. Notably, specimens we have identified as having “red” habits in our collections group only within the L. dendroidea clade, along with green and purple-green morphs of this species. All specimens that were noted as ‘green with pink tips’ in our field notes fall within the L. catarinensis clade. It is likely that Howe (1918) was examining collections of L. catarinensis when describing ‘ L. obtusa ’ from the islands as “subglobose tufts’’ that are “often greenish with red tips,” features that appear to characterize the habit of this species based on our observations and genetic sequences.

The presence of Laurencia intricata in Bermuda also has been verified with molecular data. Sequence data show that this species, first reported for the islands by Howe (1918), is conspecific with specimens from the Caribbean Antilles, the type locality of this species. Intraspecific divergence values are 0.1% in COI-5P and 0.3% in rbc L ( Table 1). We have discovered a specimen of L. intricata among Hervey’s archived