Ohelopapa Fexilis (Setch.) F.Rousseau, Martin-Lescanne, Payri & L.Le Gall

Florence Rousseau, Delphine Gey & Akira Kurihara, 2017, Molecular phylogenies support taxonomic revision of three species of Laurencia (Rhodomelaceae, Rhodophyta), with the description of a new genus, European Journal of Taxonomy 269, pp. 1-19 : 9-10

Ohelopapa Fexilis (Setch.) F.Rousseau, Martin-Lescanne, Payri & L.Le Gall comb. nov.

Fig. 3 ; Table 2

Basionym

Laurencia fexilis Setch. , University of California Publications in Botany 12: 101, pl. 19, fgs 1–6 ( Setchell 1926) (in Tahitian algae collected by Setchell W.A., Setchell C.B. & Parks H.E., 1926).

Type material

Holotype

FRANCE: French Polynesia, Tahiti, UC261333 deposited at the Jepson Herbaria (JEPS, University of California, Berkeley).

Original material is also preserved in SAP fde Masuda et al. (1999, 2006).

Type locality

Reef at Tahara Mountain, Tahiti.

Other material examined

FRANCE: French Polynesia, Tahiti, reef at Tahara Mountain [type locality], 24. Mar. 2007, André Pham 01A-07/UPF4223 (UPF).

Distribution

Tropical regions in the Pacifc ( Setchell 1926; Cribb 1983; Masuda et al. 1999), in the Indian Ocean ( Silva et al. 1996) and on coasts of Japan ( Masuda et al. 2006).

Remarks

Ohelopapa fexilis ( Fig. 3A ) specimens included in this study matched previous descriptions where anatomical features were thoroughly illustrated ( Setchell 1926; Masuda et al. 1999, 2006). Notably, we observed, in the outermost cortical layer, translucent cells without secondary pit connections, whereas the inner cortical layer (just below this) consisted of pigmented cells with secondary pit connections ( Fig. 3B ). This anatomical character was highlighted by Fujii & Cordeiro-Marino (1996) for C. translucidus (M.T.Fujii & Cord.-Mar.) Garbary & J.T.Harper. Based on molecular data, Fujii et al. (2006) showed that C. translucidus pertains to genus Laurencia rather than to Chondrophycus . Interestingly, Masuda et al. (2006) used the absence of secondary pit connections between superfcial cortical cells as a new argument to support the distinction between L. fexilis and another morphologically similar species, L. tropica Yamada. It would be interesting in the future to test with molecular characters whether L. tropica belongs to the genus Ohelopapa and also to analyse the taxonomic signifcance of the presence of an outermost cortical layer formed of translucent cells without secondary pit connections.

Figures

Fig. 3. Ohelopapa fexilis (Setch.). A. Voucher specimen (01 A 07  /  UPF 4223) collected at Tahiti (type locality). B. Transversal section through outer cortex showing a translucent outermost cortical layer lacking secondary pit connections between cells.