Aureoscheda, a new genus of marine Pelagophyceae

from the Bahamas, Caribbean Sea

MICHAEL J. WYNNE1*, ROBERT A. ANDERSEN

2, LOUIS GRAF3

AND HWAN SU YOON3

1University of Michigan Herbarium, University of Michigan, Ann Arbor, MI 48108 USA2Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250 USA3Department of Biological Sciences, Sungkyunkwan University, Suwon 440–746, Korea

ABSTRACT: A new pelagophyte genus and species, Aureoscheda bahamensis, were described from a shallow marine habitaton the north shore of San Salvador Island Bahamas, Caribbean Sea. The alga typically appeared as small, delicate goldensheets that reached ~ 10 mm; however, earlier stages may have been sacs that ultimately split open into the flatmonostromatic blades. Cells were ~ 5 lm wide and 10 lm long in dried material that was re-hydrated. There were twochloroplasts per cell, and each cell was surrounded by a thin cell wall. Cells were held together in a gelatinous matrix, andcells were regularly arranged in rows. Molecular phylogenetic analyses were conducted using the plastid encoded psaA,psaB and rbcL genes. Results placed the new alga in the class Pelagophyceae, order Sarcinochrysidales. Aureoschedabahamensis was a sister to CCMP1410 (undescribed coccoid organism), Chrysoreinhardia and Aureoumbra in a combinedmolecular phylogenetic analysis.

KEY WORDS: Aureoscheda, Chrysocystis, Chrysonephos, Chrysoreinhardia, Heterokont, New genus, psaA, psaB, rbcL,Saccate, Thallus

INTRODUCTION

The Sarcinochrysidales (Chrysophyceae) was established byGayral & Billard (1977) as an order of the class Chrys-ophyceae, with two suborders, the Sarcinochrysidineae andChrysomeridineae. Some 20 years later, based upon molec-ular evidence, Saunders et al. (1997) transferred the orderfrom the Chrysophyceae to the recently established classPelagophyceae (Andersen et al. 1993). Sarcinochrysis Geitlerwas the sole genus in the suborder Sarcinochrysidineae whenit was first established by Gayral & Billard; since then,Ankylochrysis Billard (in Honda & Inouye 1995); Aureoum-bra Stockwell, De Yoe, Hargraves & Johnson (De Yoe et al.1997); Chrysocystis Lobban, Honda & Chihara (Lobban etal. 1995); Chrysonephos W.R. Taylor (Taylor 1952; Boddi etal. 1999) and Chrysoreinhardia Billard (in Hoffmann et al.2000) have been added. Finally, Chrysophaeum Lewis &Bryan may belong in the order Sarcinochrysidales (D.Honda, personal communication). From the most recentanalyses of the stramenopiles, the Pelagophyceae belong toClade S3 of the heterokont algae (Yang et al. 2012).

Gayral & Billard (1977) also placed three other ‘chryso-phyte’ families in a second suborder, Chrysomeridineae.Specifically, Chrysomeris N. Carter, Chrysowaernella Gayral& Lepailleur, Giraudyopsis Dangeard (invalidly published,Wynne & Furnari 2014), Rhamnochrysis Wilce & Markeyand ChrysonephosW.R. Taylor (with a query) were placed inthe family Chrysomeridaceae; Antarctosaccion Delepine andPhaeosaccion Farlow were placed in the family Phaeosac-cionaceae; Nematochrysopsis Chadefaud was placed in thefamily Nematochrysopsidaceae. Using molecular phyloge-

netic analyses, Chrysowaernella and Giraudyopsis weretransferred to the class Chrysomerophyceae based upongene sequence analyses (Clade S1, heterokont algae; Yang etal. 2012). From our unpublished work, we also know thatAntarctosaccion and Phaeosaccion belong in Clade S1(unpublished results). Thus, the previously mentioned generado not belong in the Sarcinochrysidales. Four remainingfilamentous genera, Chrysomeris, Chrysonephos, Nemato-chrysopis and Rhamnochrysis, have not been examined usingmolecular phylogenetic analysis, and therefore their modernclassification remains unknown.

In March 2006, a sheet-like golden alga was foundgrowing on dead coral in the shallow subtidal beach areanext to the Gerace Research Center, San Salvador IslandBahamas. The alga resembled Chrysocystis and Chryso-reinhardia (Sarcinochrysidales, Pelagophyceae). Specimenswere dried on herbarium sheets; the alga was not collectedagain, and therefore we have not conducted transmissionelectron microscope (TEM) observations. Light-microscopicobservations were not sufficient to accurately classify thealga, but we were able to extract DNA twice, once each fromtwo different herbarium sheets. In this paper, we reportplastid encoded gene sequences (psaA, psaB, rbcL) from thetwo DNA extractions, we provide morphological observa-tions, and we describe a new genus and species belonging tothe Pelagophyceae.

MATERIAL AND METHODS

Material was collected on 25 March 2006 by MJW fromdead corals, shallow subtidal zone, near the Gerace ResearchCenter, San Salvador Island, Bahamas. Specimens weredried on herbarium sheets and deposited in the University ofMichigan Herbarium (MICH), Ann Arbor, Michigan USA,

*Corresponding author (mwynne@umich.edu).DOI: 10.2216/14-055.1� 2014 International Phycological Society

Phycologia Volume 53 (5), 513–522 Published 27 October 2014

513

and that of Sunkyunkwan University (SKK), Suwon Korea.Cells were examined using an Olympus BH-2 microscopeequipped with differential interference contrast (DIC) andphase contrast lenses (Olympus Corp., Tokyo Japan).Photographs were taken using a Canon EOS Rebel T2idigital single-lens reflex camera (Canon USA, Melville, NewYork USA).

Genomic DNA was extracted (twice) from the herbariumsheets (Aureoscheda) and from cultures (other heterokontalgal taxa) using either a Dneasy Plant Mini Kit (Qiagen,Hilden Germany) or a Tissue Miniprep Kit (CosmoGenetech, Seoul Korea) according to the manufacturer’sinstructions. Polymerase chain reaction (PCR) and sequenc-ing were performed with various combinations of publishedand newly designed primers sets. The psaA gene wasamplified using the psaA130 F (AAC WAC WAC TTGGAT TTG GAA) and psaA1600R (GCA TGA ATA TGRTGW ACC AT) primers (Yoon et al. 2002). The rbcL genewas amplified using the NdrbcL2 (AAA AGT GAC CGTTAT GAA TC) forward primer (Daugbjerg & Andersen1997) and rbcLS3R (GAT CAT CTG TCC ATT C) reverseprimer (Bailey et al. 1998). The psaB gene was amplifiedusing psaB500F (TCW TGG TTY AAA AAT AAY GA),psaB1760R (CCR ATY GTA TTW AGC ATC CA) fromYoon et al. (2004) and newly designed primers set psaB513F(AAT AAY GAR TCM CGH TTM AAY CAY CA) andpsaB1761R (ACC CAT CCA ATW GTA TTT AAC ATCC). PCR amplifications were performed on a total volume of20 ll. PCR mix of 1 ll of each primer and 5–50 ng oftemplate DNA were added to the AccuPower PCR Premix(Bioneer, Daejeon Korea) containing 1 U Top DNApolymerase, 250 lM of each deoxynucleotide triphosphate(dNTP), 10 mM of Tris-HCl (pH 9.0), 30 mM of KCl, 1.5mM of MgCl2. Standard cycling parameters were an initialdenaturation at 958C for 5 min, 35 amplification cycles(denaturation at 958C for 30 s, annealing at 42–558Cdepending on the primer set for 30 s, elongation at 728Cfor 30 s), followed by a final elongation at 728C for 10 min.Post-cycling, samples were held at 48C.

PCR products were loaded onto a 0.8% standard agarosegel for electrophoresis (15–25 min at 200 V). Unsuccessfullyamplified samples were subjected to multiple amplificationsat various template DNA and/or MgCl2 concentrations.Amplified DNA was purified with the PCR purification Kit(Cosmo Genetech, Seoul, Korea) and sent to Macrogen Inc.(Seoul, Korea) for sequencing. Electropherogram outputsfor each specimen were carefully read and edited if necessaryusing the program 4Peaks version 1.7.2 (http://nucleobytes.com/index.php/4peaks). Finally, forward and reverse se-quences for the three genes were combined using Se-Alversion 2.0 (http://tree.bio.ed.ac.uk/software/seal/). Newlydetermined sequences were deposited in the GenBank (TableS1).

Published sequences were obtained from GenBank andaligned with newly acquired sequences using MAFFT

version6 (Katoh et al. 2002), set to G-INS-i strategy andwith an offset value of 0.1 and subsequently carefully refinedby eye using Se-Al version 2.0. Any ambiguous positions(e.g. N) were treated as missing during the subsequentanalyses. The latest published evolutionary models forindividual gene analysis were chosen. They were the generaltime reversible (GTR) substitution with a four-class gammadistributed rate heterogeneity (G) for the nucleotide analysisand the LG (Le & Gascuel 2008) with empirical basefrequencies (F) and G (LG þ F þ G) model for the aminoacid sequences. An independent model for each partition ofthe concatenated data was used.

Maximum likelihood analysis was performed using anewly developed R script (R core team 2012). First,bootstrap analyses [maximum likelihood bootstrap (MLB)]were conducted using RAxML version 8.0.0 (Stamatakis2014) and 1000 replications with the same evolution modelsetting as the best topology search. Second, the maximumlikelihood (ML) tree search was performed using ExaMLversion 1 (Stamatakis & Aberer 2013) using the best scoringMLB tree as a starting point. Finally, bipartition informa-tion from the MLB analyses was written on the besttopology tree using RAxML version 8.0.0.

Genetic divergence between the genera Aureoscheda,Chrysoreinhardia and Aureoumbra was estimated for theplastid encoded genes psaA, psaB and rbcL by counting thenumber of nucleotide differences and by generating matricesof uncorrected (p-) distances (number of nucleotide differ-ences/total number of nucleotides compared) using the Rimplemented dist.dna function from the ape package(Paradis et al. 2004).

RESULTS

We generated 39 new sequences of the plastid encoded psaA,psaB and rbcL that have been deposited in GenBank (TableS1). Preliminary molecular analysis (data not shown) placedthe new sheet-like alga (Aureoscheda bahamensis gen. et sp.nov.) within the heterokont algal S3 clade (i.e. Bolidophy-ceae, Bacillariophyceae, Dictyochophyceae and Pelagophy-ceae). Detailed molecular phylogenetic analyses wereaccomplished by building a three-gene dataset, combiningpublicly available and newly determined sequences from 42taxa representing the diversity among this clade (Table S1).

Maximum likelihood phylogenies using the concatenatedthree-gene datasets of both nucleotide and amino acidsequences recovered the four classes of the S3 clade with98–100% bootstrap support (Fig. 1). The tree was rootedbetween the clade of the Bolidophyceae/Bacillariophyceaeand the Dictyochophyceae/Pelagophyceae based on thecurrent view of the heterokont phylogeny (Yang et al.2012). Inside the class Pelagophyceae, two distinct groupswere strongly supported, globally corresponding to the

�Fig. 1. Maximum likelihood tree of the concatenated three-gene DNA sequence dataset of psaA, psaB and rbcL inferred using ExaML.Bootstrap values using RAxML are shown above the node for the nucleotide analysis and under the node for the amino acid analysis.Independent models were used for each selection (GTRþG for the nucleotide analysis and LGþGþ F for the amino acid analysis). Scalebar ¼ 0.05 substitutions per site.

514 Phycologia, Vol. 53 (5)

Wynne et al.: A new pelagophyte Aureoscheda gen. nov. 515

orders of Pelagomonadales (MLB 92%) and Sarcinochrysi-dales (MLB 100%). The Pelagomonadales was formed by thegenera Aureococcus, Pelagococcus and Pelagomonas andincluded three unidentified taxa. The Sarcinochrysidalesincluded the genera Aureoscheda, Aureoumbra, Chrysocystis,Chrysoreinhardia, Sarcinochrysis and two unidentified taxa.The genus Ankylochrysis was placed in an ambiguousintermediate position, which grouped with a strong supportwith the Pelagomonadales in the DNA tree (MLB 92%),while this position was weakly supported in the amino acidtree (MLB 33%).

Within the Sarcinochrysidales, two strongly supportedsister groups were identified. The genera Chrysocystis andSarcinochrysis formed a monophyletic group (MLB 94%),while the genera Aureoumbra, Chrysoreinhardia, Aureoschedaand an unidentified coccoid taxon were grouped together(MLB 94%) (Fig. 1).

Tree topologies using three single-gene datasets (Figs 2–4)were basically congruent with the tree based on a concate-nated dataset. At the class level, only the rbcL tree (Fig. 2)did not recover the sister group relationship between theclasses Bacillariophyceae and Bolidophyceae, although deepinternal relationships were very weak. Inside the Pelagophy-ceae, the monophyletic orders Pelagomonadales and Sarci-nochrysidales were recovered, while the position ofAnkylochrysis remained unclear. In the rbcL tree, Anky-lochrysis grouped with other Sarcinochrysidales species(MLB 57%); however, in the psaA and psaB trees, theposition of Ankylochrysis was within the Pelagomonadaleswith bootstrap supports of 98% and 80%, respectively (Figs3, 4). Within the order Sarcinochrysidales, the relationshipsamong the different genera were not resolved as clearly as inthe phylogeny based on the concatenated dataset. In therbcL tree (Fig. 2) the monophyletic Sarcinochrysis, with theunidentified taxon CCMP 292, was recovered (MLB 72%),while a paraphyletic Sarcinochrysis was sister to the othergenera in the psaA (Fig. 3) and psaB tree (Fig. 4).Chrysocystis was sister to Aureoscheda bahamensis butwithout strong support in the rbcL tree (Fig. 2). In the psaBtree (Fig. 4) Aureoumbra, Chrysoreinhardia and Aureoschedaformed a monophyletic group with strong support (MLB92%). Despite the low internal resolutions, all the single-genetrees recovered Aureoscheda within the Sarcinochrysidales.

Pairwise genetic distances

Genetic distances between the genera Aureoscheda, Chrysor-einhardia and Aureoumbra were estimated using the exactnumber of nucleotide differences and p-distances matrices(Table 1). The inter-generic distances estimated from theplastid markers psaA, psaB and rbcL ranged from 12.9 to15.2%, 16.5 to 19.8% and 12.8 to 16%, respectively. Incontrast, the intra-generic distances were considerably lower.

The two DNA extractions from herbarium sheets ofAreoumbra had identical gene sequences for the psaA andpsaB genes.

Morphology

The dried herbarium material was removed, re-hydrated andobserved using light microscopy. The thalli were composed ofdistinctly monostromatic layers in the form of a sheet thatarose from an attachment point (Fig. 5). The cells were notconnected to each other; instead the cells were discrete andembedded in a gelatinous matrix (Figs 6, 7). Two or four cellswere frequently contained within a distinct layer, and the layerappeared to be either a gel layer or a gelatinized old mothercell wall (Fig. 8). Some cells appeared to be surrounded by athin cell wall that separated from the cytoplasm in the re-hydrated herbariummaterial (Fig. 9). Each cell had one or twoparietal chloroplasts, and these appeared golden in colour.Other cellular features (e.g. nucleus, pyrenoid) were notdistinguished in the re-hydrated material. The alga wasmorphologically compared to other similar taxa belonging,or suspected to belong, in the order Sarcinochrysidales, classPelagophyceae (Table 2).

Aureoscheda bahamensisM.J. Wynne & R.A. Andersen gen. et sp. nov.

Figs 5–9

DESCRIPTION: mature thalli monostromatic sheets, up to 10 mmacross; cells scattered, embedded in a gelatinous matrix, often inpackets of 2–4 surrounded by a gelatinous layer or remnant parentalcell wall. Cells ovoid, approximately 5–8 lm 3 6–9 lm; thin cell wallor gel layer around some cells; each cell with one to two parietalchloroplasts. Zoospores and sexual reproduction unknown.

HOLOTYPE: M. Wynne 11675 deposited in MICH (1210562).

ISOTYPE: SKK 004000 deposited in the herbarium, SungkyunkwanUniversity, Korea

ETYMOLOGY: Aureoscheda from Latin aureus¼ golden yellow; andscheda, ¼ a sheet of paper; bahamensis, from the Bahamas.

TYPE LOCALITY: beach next to Gerace Research Center (24870N,748270W), San Salvador Island Bahamas; in the drift and on deadcoral substrate in shallow water; 25 March 2006.

DISCUSSION

The sheet-like thallus of mature Aureoscheda bahamensis isunique for the Pelagophyceae, but it is possible that thethallus is tubular or saccate in more immature forms.Because of the limited herbarium material and the lack ofadditional material from subsequent collecting trips, the

�Figs 2–4. Maximum likelihood trees inferred using ExaML. Bootstrap values using RAxML are shown above the node for the nucleotideanalysis and under the node for the amino acid analysis. Independent models were used for each selection (GTR þ G for the nucleotideanalysis and LG þG þ F for the amino acid analysis).

Fig. 2. ML tree of the plastid encoded rbcL. Scale bar ¼ 0.07 substitutions per site.Fig. 3. ML tree of the plastid encoded psaA. Scale bar ¼ 0.05 substitutions per site.Fig. 4. ML tree of the plastid encoded psaB. Scale bar ¼ 0.07 substitutions per site.

516 Phycologia, Vol. 53 (5)

Wynne et al.: A new pelagophyte Aureoscheda gen. nov. 517

gene sequences play an important role in the description andclassification of this alga. Taxa such as Sarcinochrysis andChrysoreinhardia were first placed together based uponmorphology. Currently, all known representatives of thePelagophyceae have at least one gene sequence, and manyhave multiple gene sequences (e.g. Yang et al. 2012). Formany of these taxa, their placement in the class came afterthe gene sequence data were obtained because the morphol-ogy alone does not allow class assignment for someheterokont algae. Other taxa such as Chrysophaeum orChrysonephos may belong in the Pelagophyceae, butcurrently gene sequence data are lacking for these taxa.

Two saccate genera, Chrysocystis and Chrysoreinhardia,share with Aureoscheda a morphology of scattered cellsembedded in a gelatinous matrix and a more or lessmonostromatic cell layer, i.e. the centre of the thalluscontains only a watery gelatinous substance. Chrysoreinhar-dia is a close relative of Aureoscheda in our phylogenetictrees based on three independent genes (Figs 2–4) and acombined gene analysis (Fig. 1). Chrysocystis, however, isgrouped together with Aureoscheda only in the rbcL andpsaB trees with low bootstrap supports (39% and 63%,respectively). In the psaA tree, Chrysocystis shows a strongmonophyletic relationship (MBL 90%) with two Sarcinochr-ysis strains (i.e. CCMP 3189 and CCMP 3191) that may leadto the monophyly of Chrysocystis and Sarcinochrysis in thecombined gene phylogeny (MLB 68%). Chrysocystis, basedon the single species Chrysocystis fragilis C.S. Lobban, D.Honda & M. Chihara, was described by Lobban et al. (1995)as a marine alga forming saccate macroscopic colonies. Itwas described from Guam in the western Pacific Ocean butwas later reported to occur in Hawaii, Palau, Pohnpei andon the Great Barrier Reef (Lobban & Tsuda 2003; Lobban &N’Yeurt 2006). In fact, it has been occasionally formingblooms on the Great Barrier Reef, where it can blanket tensof square meters of reef (Schaffelke et al. 2004). From theAtlantic Ocean, it has been reported from Puerto Rico(Ballantine et al. 2009). Molecular characterization of thespecies is currently limited to cultures established frommaterial collected in Guam. Chrysocystis cells are larger thanthose of Aureoscheda, and they contain four to eightchloroplasts (Table 2).

Billard (in Hoffmann et al. 2000) proposed the substitutename Chrysoreinhardia for Pulvinaria algicola Reinhard(Reinhard 1885) because the generic name Pulvinaria waspreoccupied as a fungal genus (Bonorden 1851). Pulvinariaalgicola was found growing on an alga identified asCeramium nodosum C. Agardh during the summer, 1883, inSevastopol, Crimea, in water at a depth of about 15–30 cm,but it may have been present as deep as 10 m (Reinhard1885). The colonies were small (1–2 mm), yellow-olive incolour and appeared to be somewhat transparent althoughnot hollow. Zoospores had two polar flagella.

Billard (in Hoffmann et al. 2000) made a new combinationfrom Tetraspora giraudii Derbes & Solier to Chrysoreinhar-dia giraudii (Derbes & Solier) Billard. The description of T.giraudii by Derbes & Solier (1851) lacked detail but theydescribed a bubble-like thallus with cells embedded in a

Table 1. Estimated genetic divergence between the plastid encoded psaA, psaB and rbcL sequences of the genera Aureoscheda,Chrysoreinhardia, Aureoumbra and an unidentified pelagophycean coccoid unicellular alga, CCMP1410. The number of differences and the p-distances are shown above and under, respectively.

Genetic divergence (psaA, 1596 nt)/(psaB, 1318 nt)/(rbcL, 1395 nt)

Aureoschedabahamensissample 1

Aureoschedabahamensissample 2

Chrysoreinhardiagiraudii

CCMP 2349

Aureoumbralagunensis

CCMP 1507

Aureoumbralagunensis

CCMP 1510 CCMP 1410

Aureoscheda bahamensis sample 1 — 0/0/— 45/129/— 39/116/— 39/116/— —/—/—Aureoscheda bahamensis sample 2 0.000/0.000/— — 45/129/96 39/116/106 39/116/106 —/—/94Chrysoreinhardia giraudii CCMP 2349 0.149/0.198— 0.149/0.198/0.145 — 46/108/85 46/108/85 —/—/79Aureoumbra lagunensis CCMP 1507 0.129/0.178/— 0.129/0.178/0.160 0.152/0.165/0.128 — 0/0/0 —/—/81Aureoumbra lagunensis CCMP 1510 0.129/0.178/— 0.129/0.178/0.160 0.152/0.165/0.128 0.000/0.000/0.000 — —/—/81CCMP 1410 —/—/— —/—/0.142 —/—/0.119 —/—/0.122 —/—/0.122 —

Fig. 5. Aureoscheda bahamensis. An image of the holotype specimenWynne 11675 deposited in MICH. Note the thalli formed asmonostromatic sheets.

518 Phycologia, Vol. 53 (5)

gelatinous matrix; from their illustrations, it appears that thecells were not peripheral but scattered throughout thethallus. They reported that the cells were nearly impossibleto observe even with a good microscope, but they did statethat the zoospores were yellowish and probably had twoflagella. Lagerheim (1893) suggested that T. giraudii may bea species of his new genus Phaeocystis but made no formalnomenclatural change. Two years later, De Toni (1895)transferred this species to Phaeocystis. While details are verylimited as to whether T. giraudii is a haptophyte orheterokont, Derbes & Solier (1851) suggested that there isone forward flagellum and one trailing flagellum; acceptingthis observation, one must conclude that their alga was aheterokont, not a haptophyte. It is only by convenience thatwe accept placement of these two old and poorly describedtaxa, Pulvinaria algicola and T. giraudii, together in thegenus Chrysoreinhardia. However, there is some evidencethat T. giraudii is a member of the Pelagophyceae becauseDerbes & Solier (1851) described a tuberculate cell surfacecaused by numerous hyaline granules. These granules arecommon in the Sarcinochrysidales, and similarly Reinhard(1885) reports small grainy inclusions.

Chrysobotrys feldmannii, originally described as a memberof the class Chrysophyceae, produces an irregular mass ofcells, a few cubic millimetres in size, perhaps with a hollowcentre. The cells are 8–20 lm in size and have a firm pectic

cell wall with a tuberculate surface, and there are 4 to 12chloroplasts per cell, each with a distinct stalked pyrenoid(Bourrelly & Magne 1953). Bourrelly (1957) made Chrys-obotrys a synonym of Chrysosphaera and proposed the newcombination Chrysosphaera feldmannii (Bourrelly & Magne)Bourrelly. This alga was subsequently recombined asChrysoreinhardia feldmannii (Bourrelly & Magne) Billard &Fresnel (in Hoffmann et al. 2000). The placement of thismarine alga in the Pelagophyceae is justifiable despite thelack of ultrastructure and gene sequence data; generally,members of the Chrysophyceae are freshwater algae, theyrarely have more than two chloroplasts, and stalkedpyrenoids are unknown for ‘true’ Chrysophyceae.

Sarcinochrysis marina Geitler produces a sarcinoid thallushaving a solid mass of regularly organized cells (Geitler1930). Cells are about the same size as Aureoscheda, andSarcinochrysis has two chloroplasts per cell. We included anumber of unidentified Sarcinochrysis spp. in our analysisbecause material of the generitype S. marina (type localityCanary Islands) was not available. In addition, Aureoschedais related to the unicellular brown tide organism, Aureoum-bra lagunensis D.A. Stockwell, H.R. De Yoe, P.E. Hargraves& P.W. Johnson (De Yoe et al. 1997) and an undescribedcoccoid alga strain CCMP1410. Aureoumbra was based on asingle species that was isolated from the Laguna Madre(278280N, 978180W), Gulf of Mexico, Texas USA. Culture

Figs 6–9. Aureoscheda bahamensis. Re-hydrated wet-mount preparations from herbarium sheets.Fig. 6. Monostromatic sheet-like thallus with cells embedded in a gelatinous matrix. Scale bar ¼ 50 lm.Fig. 7. Enlarged view of herbarium material showing cells in packets of two or four. Scale bar ¼ 10 lm.Fig. 8. Cells showing the gelatinous layers (old mother cell walls?) surrounding cells (arrow). Scale bar ¼ 5 lm.Fig. 9. Enlarged view of cells showing the gelatinous layer (arrow) and cell walls (arrowheads). Scale bar ¼ 5 lm.

Wynne et al.: A new pelagophyte Aureoscheda gen. nov. 519

Table

2.ComparisonofmulticellularspeciesofthePelagophyceaebasedupontheoriginaltypedescriptions.

Taxon

Thallussize

Thallusshape

Veg.cellsize

Veg.cellshape

Plastids

Pyrenoid

Zoospore

Cellwall

Saccate

taxa

Aureoscheidabahamenesis1

upto

10cm

monostromatic

sheet,cells

peripheral

5–8

36–9

lm

ovoid

2/cell;parietal

platelike

unknown

unknown

thin

Chrysocystisfragilis2

3–5cm

long,0.5

cmwide;

occasionally30

cmlong

cylindricalor

fingerlikebut

branched,cells

peripheral

8–14

lmspherical

4–8/cell;elliptical

andsaucer-

shaped

1–2projecting

pyrenoids

4–5

lmlong,2–3

lm

wide;

single

chloroplast

none

Chrysophaeum

taylorii3

1–6cm

high

centralgel

stalks,

pendentcells

49–118

lm

long,

24–38

lmwide

ovate–cylindrical,

anteriorwith

deeptube-like

invagination

30–60/cell

possibly

the

‘granule

of

anabolite’?

9lm

long,ca.4

lm

wide;

single

chloroplast

pellicle

Chrysoreinardia

algicola

40.1–0.2

cmsphericalto

oblong–oval;

transparent,not

hollow

~7–10

lmspherical?

4/cell

??6

lm

long,4.3

lm

wide

upto

1lm

thick

Chrysoreinhardia

feldmannii5

few

cubic

mm

irregularmass,

centreprobably

hollow

83

20

lm

hem

isphericalto

spherical

4–12/cell

yes

unknown

firm

,pectic

(not

cellulosic)

Chrysoreinhardia

giraudii6

1.5

cmirregularmass,

centreprobably

hollow

7–10

lmdiam.

hem

isphericalto

spherical

2/cell

yes

unknown

unknown

Sarcinochrysismarina7

microscopic??

solidmass

ofcells,

nohollow

centre

5–9

lm

hem

isphericalto

spherical

2/cell;parietal

notreported

6–7.5

lmlong

wall;

gelatinous

matrix

Filamentoustaxa

Chrysonephoslewisii8

1–3cm

high

(mostly)uniseriate

branched

filaments

4–5–7.7

lmnear

tip,30–38

lmnear

attachment

cylindrical;

broader

than

long

2–4/cell,ovalto

band-shaped

toirregularand

lobed

none

7–8

38–9

lm,

twoplastids

verythin

Nem

atochrysopsisroscoffensis9

filamentheight

notgiven

unbranched

uniseriate

filaments

made

withH-shaped

pieces

8lm

diameter

cylindrical,

slightlylonger

thanwide

2/cell

none

notreported

thick,H-

shaped

1Thispaper.

2Lobbanet

al.(1995).

3Lew

is&

Bryan(1941).

4Reinhard

(1885).

5Bourrelly

&Magne(1953).

6Hoffmannet

al.(2000).

7Geitler

(1930).

8Taylor(1951,1952).

9Chadefaud(1947).

520 Phycologia, Vol. 53 (5)

strain CCMP1410 was collected from the Sargasso Sea nearBermuda (29858007 00N, 63851034 00W) from a depth of 84 m(0.5% light level).

Chrysonephos lewisii (W.R. Taylor) W.R. Taylor wasdescribed from the Dry Tortugas, Florida, USA andBermuda (Taylor 1951, 1952), and it has been found inMicronesia (Lobban et al. 1995), Puerto Rico (Ballantine &Aponte 1997), the Mediterranean Sea (Sartoni et al. 1995)and Hawaii (Huisman et al. 2007). Chrysonephos, however, isa uniseriate to multiseriate branching filament, whereasAureoscheda forms a monostromatic sheet. Chrysophaeumtaylorii Lewis & Bryan was first reported from the DryTortugas, Florida USA, and it superficially resemblesAureoscheda; however, cells of this species are 49–118 lmlong, 24–38 lm broad, much larger than those of Aureocheda(Table 2) (Lewis & Bryan 1941). Although Chrysophaeumtaylorii was first classified in the Cryptophyceae, unpublishedTEM observations and an 18S rRNA sequence placeChrysophaeum, collected from Okinawa, Japan, in thePelagophyceae (D. Honda, pers. comm.). Chrysophaeum isalso known from Bermuda (Taylor 1960), Sardinia (Cortes-Altamirano et al. 2008; Caronni et al. 2010, 2014) and theAegean Sea (Aktan & Topaloglu 2011).

If one considers the morphological features of these algae,no previous golden alga has been described as a mono-stromatic sheet. The molecular analyses show that Aureo-scheda is distinct from all members of the classPelagophyceae. Therefore, we conclude that Aureoschedarepresents a new genus and species with a unique morphol-ogy and a phylogenetic position near the colonial goldenalgae Chrysoreinhardia, Chrysocystis, Sarcinochrysis and theunicellular alga Aureoumbra.

ACKNOWLEDGEMENTS

We thank Maria Lindseth for translating the Reinhard 1885paper, and we thank Eun Chan Yang, Hee Jeong Kim andSu Yeon Kim for technical assistance. This work wassupported by the Korean Rural Development Administra-tion Next-generation BioGreen21 (PJ009525), by the Na-tional Research Foundation of Korea (NRF) (MEST, No.2014R1A2A2A01003588) and by a grant from the USNational Science Foundation (1317114) to HSY.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be foundonline at http://dx.doi.org/10.2216/14–055.1.s1

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Received 19 June 2014; accepted 20 August 2014Associate Editor: John Huisman

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