Hypnea yokoyana Nauer, Cassano & M.C. Oliveira, 2016

Nauer, Fabio, Cassano, Valéria & Oliveira, Mariana C., 2016, Hypnea wynnei and Hypnea yokoyana (Cystocloniaceae, Rhodophyta), two new species revealed by a DNA barcoding survey on the Brazilian coast, Phytotaxa 268 (2), pp. 123-134 : 128-129

Hypnea yokoyana Nauer, Cassano & M.C. Oliveira , sp. nov. ( Figs 8–12 )

Plants erect, epilithic, reddish-pink when fresh, terete, fleshy in texture, 1–3.5 cm long ( Figs 8, 9 ), attached to the substratum by several discoid holdfasts and by rare secondary discoid holdfasts at the apices of lateral branches ( Fig. 10 ). Anastomoses absent. Main axis distinguishable, 500–725 μm in diameter in the middle portions. Branching irregular at acute or right angles, with 1–2 (–3) orders of branches. First-order branches more slender than the main axis, 200–500 μm wide. Lateral branches may be more slender than main axes, tapering toward the apices, 200–275 μm wide ( Fig. 10 ). Apices straight without hooks or tendrils. Spine-like branchlets straight, at acute or right angles, sparse, irregular to alternately scattered throughout the thalli, 80–900 μm long and 70–210 μm in diameter. Thalli with 1–2 layers of pigmented cortical cells and 1–2 layers of hyaline medullary cells ( Fig. 11 ). Cortical cells rounded, 7–12 μm long and 5–12 μm in diameter. Axial cells rounded, smaller than periaxial cells, 35–52 μm long and 45–57 μm in diameter ( Fig. 12 ). Each axial cell is surrounded by 4–5 periaxial cells; periaxial cells rounded to elliptical, 75–225 μm long and 80–162 μm in diameter. Lenticular thickenings not observed. Fertile plants not observed.

Type:— BRAZIL. Bahia: Porto Seguro, Praia de Mutá, 16.211°S, 039.004°E, intertidal, coll. F. Nauer, tetrasporangial plant, 18 April 2012 (holotype SPF 57602), GenBank accession numbers for rbc L KX426554, COI-5 P KX426540, and UPA KX426560.

Distribution and habitat:— BRAZIL: Rio de Janeiro: Angra dos Reis, Ilha Grande, Laje Branca, 18 April 2012, F. Nauer (SPF57519). São Paulo: Laje de Santos, 24 February 2011, R. Rocha-Jorge (SP365689). Santa Catarina: Bombinhas, Ilha do Arvoredo, 25 February 2012, F. Nauer, B. Torrano-Silva & C.A. Azevedo (SPF57488).

Etymology: The specific name honors Dr Nair S. Yokoya from the Institute of Botany, São Paulo, Brazil, for her important contribution to the knowledge of the physiology of marine benthic algae, especially the genus Hypnea .

Figures

FIGURES 8–12. Holotype of Hypnea yokoyana. 8. Habit of the thallus. 9. Detail of the apical portion showing thinner lateral branches. 10. Detail of a lateral branch showing secondary discoid holdfast (arrow). 11. Transverse section of the thallus. 12. Transverse section of the thallus showing axial cell (a) and periaxial cells (p).