Yuzurua, 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 : 16-17

THE GENUS YUZURUA IN BERMUDA

Reports of the species currently known as Yuzurua poiteaui appear in the earliest literature for Bermuda as Laurencia gemmifera Harvey ( Rein 1873; Dickie 1874; Hemsley 1884). This species was archived pro parte as P.B.-A. no. 1937 (as L. tuberculosa ; Collins et al. 1913), and as mentioned above, represents Y. poiteaui in a heterotypic collection; however a specimen of the same P.B.-A. number in another fascicle can be attributed to L. intricata . Collins & Hervey (1917)

first reported the species in Bermuda as Laurencia poiteaui (J.V.Lamouroux) M.Howe. This name was later transferred to Chondrophycus ( Nam 1999) and then to Palisada ( Nam 2006, 2007) based on phylogenetic and morphological evidence. Using the rbc L sequences of Y. poiteaui (as Chondrophycus poiteaui (J.V.Lamouroux) K.W.Nam ) and C. gemmiferus (Harvey) Garbary & J.T.Harper, Díaz-Larrea et al. (2007) concluded that the latter species, different only in minor anatomical characters and should be reduced to a synonym of Palisada poiteaui (J.V.Lamouroux) K.W.Nam ( Sentíes & Diaz-Larrea 2008) . Molecular data have also prompted the elevation of Yuzurua , initially a subgenus of Chondrophycus recognized by Nam (1999), to the generic level ( Martin-Lescanne et al. 2010) with Y. poiteaui as the generitype. This species appears to be relatively rare in Bermuda at present, with only one collection confirmed with molecular data (intraspecific divergence of 0.2% in rbc L). Yuzurua poiteaui specimens were far more abundant in our Florida Keys and US Virgin Islands collections.

Sequence data have shown that Palisada iridescens (M.J.Wynne & D.L.Ballantine) K.W.Nam was closely related to Yuzurua , and the new combination, Y. iridescens was proposed ( Sentíes et al. 2015). Our data agree with this transfer, as previous records of this species in Bermuda ( Schneider & Lane 2007, as Chondrophycus iridescens ) grouped with the Yuzurua clade in both our COI-5P and rbc L barcode analyses ( Table 1) and rbc L phylogeny ( Fig. 1). While sequence data for Y. iridescens from Guadeloupe, Mexico and St. Kitts are available in GenBank, we chose to exclude these data from our analysis. The sequences of Y. iridescens from St. Kitts and Guadeloupe were short (886 bp and 660 bp, respectively) and only overlapped by 173 bp with our rbc L sequences, an inadequate number for meaningful comparison. Furthermore, the three sequences of Y. iridescens from Senties et al. (2015) deposited in GenBank are quite variable, despite their stating that the divergence among them was extremely low at 0.01-0.02%. Our analysis shows much larger distance values of 1.4-5.5%. It is clear that the L. iridescens complex needs reassessment so these issues can be resolved. Additional genes and longer sequences from specimens at or near the type locality will be imperative for definitive phylogenetic results.

Our analysis has also resolved a unique sequence from a Bermuda specimen in this clade sister to Yuzurua poiteaui (4.3% divergence). Thus far, we are able to confirm only a single specimen representing this entity and will require additional collections before we can verify that these represent a unique third species in the genus. At present, this taxon will be regarded as Yuzurua sp. 1 Bda ( Fig. 1; Appendix 1).