Newhousia yhaga C.W.Vieira, De Clerck et Payri, 2016

Vieira, Christophe, De Clerck, Olivier & Payri, Claude E., 2016, First report of the Hawaiian genus Newhousia (Dictyotales, Phaeophyceae) from Madang, Papua New Guinea and description of the new species N. yhaga sp. nov., Botanica Marina (Warsaw, Poland) 59 (1), pp. 31-37 : 34-35

Newhousia yhaga C.W.Vieira, De Clerck et Payri sp. nov.

( Figure 2A–O ).

Description

Thalli tightly adherent to and following the contours of dead-coral substrata ( Figure 2A, B ), fronds ovoid to irregularly lobed in surface outline ( Figure 2C–E ), to 3–4 mm in diameter, green khaki-gray ( Figure 2A, B, D ) or reddishbrown ( Figure 2C ) in color, consisting of multiple layers of imbricated, marginally meristematic encrusting blades ( Figure 2F, G ) cemented to the substratum and to each other ( Figure 2C ) across the whole of the undersurfaces and without anchoring rhizoids; stack of blades to 1 mm thick. Blades extend peripherally from a continuous marginal meristem ( Figure 3E, H–J ), 45.7±5.1 µm thick, bilayered, cells of the epidermal and hypodermal layers 11.3±2.4 µm and 34.3±3.9 µm thick respectively. Epidermal cells rectilinear in surface ( Figure 2H–K ), cross-sectional ( Figure 2N ). Hypodermal cells cuboidal in cross-section ( Figure 2N ), rectilinear or in long section ( Figure 2O ), 32.3±3.2 µm in width by 59.7±3.9 µm in length. Juvenile hairs ( Figure 2L, M ) clustered. Oogonia, antheridia and sporangia unknown. Differing from N. imbricata by (1) the distinctive radial development of surface blades from points of origin and (2) the 4% difference in rbc L nucleotide sequences [PC0063019 ( IRD 11128) and IRD 11129].

Ethymology

The epithet “yhaga ” comes from the word “Yhag”, which is the general name for brown algae in Bel language that is spoken by the villages surrounding Madang Lagoon and in other areas in Madang province.

Holotype

PC0063019 ( IRD11128 ), leg. C. Payri (13.xi.2012). Figure 2A, B .

Type locality

Paeowa Island , Madang Lagoon, Papua New Guinea (05.1745° S; 145.833° E), thalli on dead coral at - 10 m.

Distribution

Endemic so far to the northeastern shore of Papua New Guinea ( Figure 1 ).

Habitat

Thalli consisting of multiple layers of tightly adhering crusts several cm 2 in surface area and cemented to hard substrata, intermixed with encrusting coralline algae ( Figure 2B, D ) at upper levels of inner and outer reef slopes from low intertidal to depths of 10 m in areas of strong to moderate water movement.

Specimens examined

1) Paeowa Island (PCT29; 5.1745° S; 145.833° E), (C. Payri, 13.xi.2012; IRD11128 ). Malamal Anchorage, Madang, Papua New Guinea (PCT12; - 5.11995° S; 145.823° E), Madang, Papua New Guinea, 18 November 2012, leg. C. Payri (C. Payri, 18.xi.2012; IRD11129 ) .

Figures

Figure 1: Map showing the location of Madang, Papua New Guinea, where Newhousia yhaga C.W.Vieira, De Clerck et Payri, sp. nov. was collected.

Figure 2: Newhousia yhaga sp. nov. habit and anatomical features. (A, B) Two aspects of the holotype specimen, showing its predominantly olive-green hue. A coralline red alga (Figure 2B, arrow) is epiphytic on the Newhousia crust. (C) Detail of radially growing adjacent and overlapping blades on the surface of the holotype. (D) Fracture of the Newhousia crust exposing underlying blades (arrow). (E) Detail of one of the single surface blades irregularly spreading from the central point (arrow) that initiated its growth. (F, G) Medium and high-power magnifications of banding shown by overlapping layers of blades (dark lines) and calcium carbonate (white lines) that comprise the consolidated crusts of a Newhousia thallus. Newhousia is cemented to coral substratum (Figure 2F, arrow). (H–J) Stages in radial development of surface blades from points of origin (arrows). (K) Surface view of aligned, rectilinear cells of the epithallus. (L, M) Low- and high-power details of cluster of erumpent filaments that may represent juvenile hairs. (N) Cross section of single blade showing double row of rectilinear epithallial cells overlying each cuboidal hypothallial cell. (O) Longitudinal section of single blade showing aligned epithallial row overlying a rectilinear hypothallial cell.

Figure 3: Bayesian tree, generated with MrBayes, based on the concatenation of cox3, psbA and rbcL gene sequences of Phaeophycean species including Newhousia imbricata and Newhousia yhaga sp. nov. The values shown at each node represent the maximum likelihood (left) and posterior probability (right) values. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site.