Yonagunia taiwani-borealis S.-M.Lin, Y.-C.Chuang & De Clerck

Yonagunia taiwani-borealis S.-M.Lin, Y.-C.Chuang & De Clerck

( Fig. 1 View FIG )

Journal of Phycology 56: 1550, figs 6, 7 ( Lin et al. 2020).

SPECIMENS EXAMINED. — Indonesia • Bali, Nusa Lembongan Island, on the left side of Dream Beach ; 23.VI.2017; S.M. Boo leg.; PKNU00668 ( G76376 ); GenBank: PV030967 ; PKNU00669 ( G76377 ), GenBank: PV030968 ; PKNU00670 ( G76378 ), GenBank: PV030969 ; PKNU00671 ( G81651 ), GenBank: PV030970 .

DESCRIPTION

Thalli ( Fig. 1A View FIG ) were found epilithic on rocky intertidal beds and also to the shallow sublittoral zone, up to 12 cm in height, bushy, erect, bright to dark red. Single to several blades arise from discoidal to crustose holdfast. Main axes were terete basally and then gradually becoming compressed to flattened. Branches were feather-like to subdichotomously branched four to six orders. Blade structure was multiaxial, consisting of a cellular cortex and a compact medulla.Cortices were unilaterally thickened, while the medulla was filled with secondarily produced, densely entwined filaments.

Tetrasporangial sori were formed on the margins of blades and roundish, heart-shaped, or elongate ( Figs 1B, C View FIG ). Tetrasporangial initials were cut off from inner cortical cells and elongated. Tetrasporangia were ellipsoidal, cruciate or decussate, and 10-13 µm in width and 27-44 µm in length ( Fig. 1D View FIG ). Female and male thalli were not found in the present collections.

PLASTID rbc L ANALYSIS

Four rbc L sequences (1 205 bp) of Yonagunia tawaini-borealis generated in the present study were identical in sequence. The pairwise sequence difference between the southern Indonesia and the Taiwanese type material ( MT501503 View Materials ) was 0.08%. Phylogenetic analysis of the rbc L gene sequences revealed that Y. taiwani-borealis both Indonesian and Taiwanese specimens are positioned in a poorly resolved clade (70% MLBS, less than 0.9 BPP) with Y. zollingeri from Indonesia ( Fig. 2 View FIG ). The ancestor of these two species again formed a well resolved clade with Y. maillardii (92% MLBS, 1.0 BPP).