Corallina marginata J. Ellis et Solander 1786 , p. 115

Schneider, Craig W., Popolizio, Thea R., Spagnuolo, Dylan S. & Lane, Christopher E., 2016, Notes on the marine algae of the Bermudas. 15. Dichotomaria huismanii (Galaxauraceae, Rhodophyta), a new species in the D. marginata complex from the western Atlantic, Botanica Marina (Warsaw, Poland) 59 (1), pp. 13-29 : 17-23

Corallina marginata J. Ellis et Solander 1786, p. 115 , pl. 22 figure 6 ( Figure 3 ).

Description

Rosy-brown plants to 10 cm tall and 13 cm across, composed of dichotomously branched flattened axes with thickened margins, these showing faint annulations; axes mottled in appearance when dried; internodes 4.7–13.7 mm long and 1.6–2.6 mm wide; axes branching dichotomously at angles of 72–89°; cortex of sporophytes composed of two layers of cells, outer cortical assimilatory cells subspherical to ovoid, 20–40 µm long and (21–) 33–49 µm diameter, and an inner layer of flared stalk cells each bearing 1–2 assimilatory cells, 15–36 µm long and 5–10 µm diameter (at narrowest point); stalk cells borne typically in pairs though occasionally singly on the outer surface of the inner cortex; stalk cells most commonly unicellular, rarely two-celled; inner cortex consisting of typically one, occasionally two, layers of transversely ovoid to rectangular cells, 50–115 µm diameter and 25–68 µm high; subcortical cells subspherical at margins; medullary filaments extending from subcortical cells, 7–13 µm diameter; gametangia and tetrasporangia not seen in our sequenced specimens.

Type locality

“… on the shore of one of the Bahama islands”, West Indies, western Atlantic Ocean ( Ellis and Solander 1786).

Distribution

Formerly reported as pantropical, genetically verified specimens are known from Guadeloupe, Puerto Rico and St. Croix, USVI (West Indies).

Selected collections

St. Croix, Virgin Is. – T. R. Popolizio ( TRP)/ C. E. Lane ( CEL)/ E.D. Salomaki ( EDS) 13-24-1 [ STX 032] ( Figure 4 ), TRP / CEL / EDS 13-25-9 [ STX 054] (see Table 1 for collection details).

Remarks

As discussed above, two St. Croix collections genetically matched other sequenced specimens from Guadeloupe and Puerto Rico, as well as the description of Dichotomaria marginata provided by Papenfuss et al. (1982). This has allowed us to identify STX 032 and STX 054 ( Figures 1 and 2 ) as true representatives of D. marginata in the West

Species Voucher nos. Collectors/date Collection site COI-5 P rbc L

Galaxauraceae Actinotrichia fragilis (Forsskål) GWS 000151 J. Huisman/ 17 Aug. 1995 Ningaloo Reef, Western Australia, KT886155 BØrgesen Australia

– T. Schils, K. Pauly and E. Bandar Khayran, Capital Area, Oman EU 095253

Demeulenaere/ 28 Oct. 2004

CNU 32154 20 Jan. 2006 Bonbon, Cagayan de Oro, Philippines KC609385

Actinotrichia robusta Itono – S- L. Liu and S. M. Lin/ 3rd Nuclear Power Outlet, Kenting AY688011

1 Apr. 2003 National Park , Taiwan

CNU 32279 K. Lewmanomont / 6 Apr. 2010 Similan I., Phang Nga, Thailand KC609386

Dichotomaria apiculata (Kjellman) SAP 095732 16 Jun. 2002 Reihoku , Amakusa , Kumamoto AB117635 Kurihara et Masuda Prefecture, Japan

TUNG 05369 S.- M. Lin and S.- L. Liu/21 Jul. Sail Rock, Kenting National Park, Taiwan AY688020

2002

CNU 32163 3 Dec. 2002 Sungsan, Jeju, South Korea KC768178

Dichotomaria australis (Sonder) SAP 101111 A. Kurihara and No. 16 Beach, Rye, Victoria, Australia AB258443 Huisman , J. T. Harper et G. W. S. Shimada / 28 Nov. 2003 Saunders SAP 101108 A. Kurihara and S. Shimada / Jervis Bay, New South Wales, Australia AB258440

4 Dec. 2003

Dichotomaria diesingiana – M. Hommersand / 9 Jul. 1993 Sharks Bay, Port Alfred, Cape Province, AY688026 (Zanardini) Huisman , J. T. Harper et South Africa G. W. Saunders

Dichotomaria falcata (Kjellman) – 24 Jul. 2001 Toji, Shimoda, Shizuoka Prefecture, Japan AB117629 Kurihara et Masuda CNU 032192 K. M. Kim / 31 Jul. 2009 Oura Bay, Shimoda, Japan KF752527

Dichotomaria hommersandii S.- L. – M. Hommersand / 20 Jul. 1993 Riet River, Port Alfred, Cape Province, KC253901 JX072968 Liu et S.- M. Lin South Africa

Dichotomaria huismanii CWS / CEL / TRP 10-5 - 13 C. W. Schneider , C. E. Lane, Off Frick’s Beach , Tucker’s Town , KU321660 C. W. Schneider, Popolizio et [ BDA 0024 ] T. R. Popolizio / 19 Aug. 2010 Bermuda I., Bermuda (10–12 m) Spagnuolo TRP 12-117- 5 [ BDA 1492 ] T. R. Popolizio / 20 Sep. 2012 Hog Breaker , north shore Bermuda I., KU321661 KU321674

(holotype) Bermuda (12 m)

TRP 12-151 - 11 T . R. Popolizio / 16 Nov. 2012 Southwest of North Rock , Bermuda I., KU321659

[ BDA 1669 ] Bermuda (12 m)

Dichotomaria intermedia WRT 1934 - 164 W. R. Taylor / 17 Jan. 1934 Isabela Island , Galapagos I ., Ecuador KF752506 ( R. C. Y. Chou) Wiriyadamrikul , CNU 032199 K. M . Kim / 24 Oct. 2009 Gerupuk, Lombok, Indonesia KF752532 KF752509 M. J . Wynne et S. M . Boo

Dichotomaria latifolia ined. – S.- L. Liu and W. L. Wang / Tahsianglan, Taipei County, Taiwan KF752529 AY688021 ( Galaxaura latifolia Tak. Tanaka) 25 Jan. 2003

Species Voucher nos. Collectors/date Collection site COI-5 P rbc L Dichotomaria marginata – S. Mege / 27 May 1995 Anorde Rocks, St. Prorjono, Guadeloupe, AY688019 ( J. Ellis et Solander) J. V. Lamouroux West Indies

– J. Hughey/ 29 Jul. 1996 Puerto Libertad, Sonora , Gulf of AY688022 California, Mexico

GR 20002006 G. Richards / 26 Sep. 2000 Mirbat, Dhofar, Oman KF752510 – 19 Jul. 2001 Ookataura, Hachijo Island, Tokyo, Japan AB117630 – S. L. Liu and L. M. Liao /7 Nov. Sulpa I., Cebu, Philippines AY688017 2002

GWS 001893 H. Ruiz/ 20 Oct. 2003 Lajas, Turrumote Reef, La Parguera, KC130147 KC134339 Puerto Rico

CNU 032166 E. C. Yang / 14 Dec. 2003 Camotes I., Cebu, Philippines KF752533

ARS 02613 A. Sherwood / 21 Mar. 2007 Makapuu, Oahu I., Hawaii, USA HQ423119

CNU 032231 J. Wiriyadamrikul / 5 Apr. 2010 Similan I., Phang Nga, Thailand KF752534 KF752512 TRP / CEL 13-24 - 1 T. Popolizio , C. Lane and E. Alien Nation Reef, Frederiksted, St. Croix , KU360125

[ STX 032] Salomaki/ 19 Nov. 2013 US Virgin Is. (15–16 m)

TRP / CEL 13-25 - 9 T. Popolizio , C. Lane and E. Cables Reef, west end St. Croix , US Virgin KU321662 KU321676 [ STX 054 ] Salomaki / 20 Nov. 2013 Is. (13–14 m)

Dichotomaria cf. marginata ARS 03619 A. Sherwood / 23 Mar. 2008 Hale O Lono Harbor, Molokai I., Hawaii, USA HQ422899

Dichotomaria obtusata ( J. Ellis et – C.- S. Lin / 15 Jun. 2002 Tiaoshih, KNP, Taiwan AY688024 Solander) Lamarck

SAP 095741 15 Jul. 2002 Itoman , Okinawa Island, Japan AB117632 SAP 101115 A. Kurihara and S. Shimada / Parakeand Bay , Rottnest Island, Australia AB258447 13 Nov. 2003

CNU 021562 J. Wiriyadamrikul / 8 Apr. 2012 Surin Islands, Phang Nga, Thailand KF752536 KF752514 Dichotomaria obtusata v. major WRT 1949 - 288 W. R. Taylor / 15 May 1949 Tucker’s Town Bay , Hamilton I., Bermuda KF752537 KF752515 ( W. R. Taylor ) M. J. Wynne (holotype)

CWS / CEL / TRP 10-5-3 C. W. Schneider, C. E. Lane, Off Frick’s Beach, Tucker’s Town, KU 321671

[ BDA 0004 ] T. R. Popolizio / 19 Aug. 2010 Bermuda I., Bermuda (10–12 m)

TRP 12-42 - 7 [ BDA 0949 ] T. R. Popolizio / 14 Mar. 2012 Middle buoy, Eastern Blue Cut channel , KU321672

blue hole, north of Daniel’s Head,

Somerset Is., Bermuda (16 m)

TRP 12-160 - 2 [ BDA 1737 ] T. R. Popolizio/ 1 Dec. 2012 Wreck of the Hermes, south shore KU321673

Bermuda I., Bermuda (23 m)

Dichotomaria papillata (Kjellman) SAP 095740 18 Jun. 2002 Reihoku , Amakusa , Kumamoto AB117631 Kurihara et Masuda Prefecture, Japan

Dichotomaria spathulata (Kjellman) SAP 101113 A. Kurihara and Green Island, Rottnest I., W. A., Australia AB258445 Kurihara et Huisman S. Shimada / 16 Nov. 2003

Species Voucher nos. Collectors/date Collection site COI-5 P rbc L Dichotomaria tenera (Kjellman) – M. Hommersand / 24 Jul. 1993 Palm Beach , Natal, South Africa AY688023 Huisman , J. T. Harper et G. W. Saunders CNU 032161 S. M. Boo / 17 Aug. 2005 Rocky Bay , Kwazulu Natal, South Africa KF752540 Dichotomaria sp. 1 CNU 032178 S. M. Boo / 10 Mar. 2005 Pagudpud , Ilocos Norte, Philippines KF752522 Dichotomaria sp. 2 CNU 032180 S. M. Boo / 11 Mar. 2005 Pangil , Ilocos Norte, Philippines KF752523 Dichotomaria sp. 3 CNU 023023 S. M. Boo / 6 Jun. 2012 Lombok , Indonesia KF752520 Dichotomaria sp. 4 CNU 032175 S. M. Boo / 17 Aug. 2005 Rocky Bay , Kwazulu Natal, South Africa KF752524 Dichotomaria sp. 1 CRB MJW 10514 M. J. Wynne / 24 Nov. 1995 Sand Bank Bay , St. Kitts, Lesser Antilles KU321657 KF752521 TRP / CEL 13-29 - 2 T. Popolizio , C. Lane and Salt River Wall , north shore St. Croix , US KU321658 KU321675

[ STX 099] E. Salomaki/ 21 Nov. 2013 Virgin Is., Lesser Antilles (18–22 m)

Galaxaura cuculligera Kjellman SAP 095742 18 Jun. 2002 Reihoku , Amakusa, Kumamoto AB117633 Prefecture, Japan

Galaxaura divaricata (Linnaeus) ARS 00995 B. Pauahi / 18 Mar. 2004 Manele Bay, Lanai I., Hawaii, USA HQ422677 Huisman et R. A. Townsend Galaxaura filamentosa R.C.Y. Chou – S.- M. Lin / 17 Apr. 2001 Five Caves, Orchid Is., Taiwan AY688006 ARS 03487 A. Sherwood / 11 Oct. 2007 Sandy Beach, Oahu I., Hawaii, USA HQ422797

Galaxaura pacifica Tak. Tanaka SAP 095744 15 May 2002 Higashi Port, Haha-jima, Bonin I., Japan AB117638 – L.- M. Liao / 19 Feb. 2003 Bulusan, Sorsogon, Philippines AY688004

Galaxaura rugosa ( J. Ellis et GWS 000144 J. Huisman/ 28 Nov. 1995 Barrow I., Western Australia, Australia KT886158 Solander) J. V. Lamouroux – M . Hommersand /27 Feb . Las Playas Piedras, Bahia San Carlos, AY688003 1998 Mexico

– S.- L. Liu and C.- S. Lin/11 Apr. Chiupeng, KNP, Taiwan AY687998

2002

– L.- M. Liao/ 19 Feb. 2003 Bulusan, Sorsogon, Philippines AY688000

ARS 02608 A. Sherwood / 17 Mar. 2007 Kaaawa Beach Park, Oahu I., Hawaii, USA HQ423122

CWS / CEL / TRP 10-22-7 C. Schneider, C. Lane and Capt. Williams’ Bay, south shore KU 321663

[ BDA 0341 ] T. Popolizio / 23 Aug. 2010 Bermuda I., Bermuda (intertidal)

TRP 12-72 - 11 [ BDA 1180 ] T. R. Popolizio / 14 Jun. 2012 Annie’s Bay , St David’s I., Bermuda (0–3 m) KU321665

TRP 12-117 - 3 [ BDA 1490 ] T. R. Popolizio/ 20 Sep. 2012 Hog Breaker , north shore Bermuda I., KU321666

Bermuda (12 m)

CWS / CEL / TRP 13-12-9 C. Schneider, C. Lane and Sand Key Lighthouse Reef, Key West, FL, KU 321667 KU 321678

[ KW 176 ] T. Popolizio / 30 May 2013 USA (6–8 m)

CWS / CEL / TRP 13-12-19 C. Schneider, C. Lane and Sand Key Lighthouse Reef, Key West, FL, KU 321668

[ KW 186 ] T. Popolizio / 30 May 2013 USA (6–8 m)

TRP 13-20 - 1 [ BDA 1868 ] T. Popolizio / 18 Sep. 2013 Whalebone Bay , St. George’s I., Bermuda KU321664 KU321677

(0–1 m)

SAP 101116 A. Kurihara and S. Shimada Rottnest Island, Western Australia AB258448

Indies, a species with a type locality in the Bahamas ( Silva et al. 1996). All of the genetic collections made in St. Croix identified as D. marginata have the anatomy of sporophytes defined for the species, unfortunately none bearing tetrasporangia. Thus, we cannot provide tetrasporangial size and shape nor the anatomy or reproduction in gametophytes of these genetically significant D. marginata vouchers. Although there are reports about these features in earlier literature (e.g. BØrgesen 1916, Howe 1918b, Taylor 1960, Papenfuss et al. 1982), without a molecular tie to this species where crypsis is now reported, we are hesitant to link that information here.

Similar to what Huisman et al. (2004) found for the species, tetrasporic St. Croix representatives of D. marginata have “the presence of a distinctly thickened margin (particularly noticeable when dried)” and a “cortex of the tetrasporophyte bearing paired subspherical cells (at least some with a small terminal spine)” ( Figure 5 ). As was pointed out in the Ellis and Solander (1786) protologue, the flattened axes of D. marginata are more pronounced when removed from the water, the first collections being washed up and dried on a Bahamian beach. Our specimens have three, or occasionally four, layers of cells including stalk and outer assimilatory cells. The assimilatory cells of St. Croix D. marginata are subspherical to ovoid in cross-section ( Figure 5 ), and appear circular to ellipsoidal in surface view ( Figure 6 ). Some, but not a majority, of the assimilatory cells are apiculate, these cells usually paired on stalk cells that are mostly paired on outer subcortical cells ( Figure 5 ). The subcortical cells are transversely ovoid to rectangular, and occasionally subspherical at the margins ( Figure 5 ).

Howe (1918b) was the first to consider Galaxaura occidentalis BØrgesen (type locality= Virgin Islands) as the gametophyte generation of G. marginata , and BØrgesen (1920) and subsequent workers ( Taylor 1960, Papenfuss et al. 1982) followed his supposition. Howe (1918a) mentioned gametophytic specimens in his account of G. marginata in the Bermuda flora, but it remains unclear whether he was referring to actual Bermuda gametophytes or rather to the gametophytes he was working on at the same time from the West Indies ( Howe 1918b). We have been able to observe the gametophytic holotype of G. occidentalis [in C], most reasonably the alternate generation of the sporangial D. marginata , but this requires genetic confirmation. It would be helpful to find sporophytes and gametophytes of D. marginata in a single Bahamian or West Indian population to confirm this supposition, both generations matching genetic sequences already linked to this species from the West Indies.

A second genetic species, Dichotomaria sp. 1 CRB, was collected in St. Croix and St. Kitts ( Figures 1 and 2 , Tables 1 and 2), and the St. Croix isolate represents the gametophytic stage of an undescribed species in the D. marginata complex. The St. Croix specimen has anatomical similarities with the type of G. occidentalis ; unfortunately, it is genetically distinct from local and regional D. marginata . We only have two representatives of this species from the West Indies, thus until additional specimens are obtained and sequenced, Dichotomaria sp. 1 CRB will remain undescribed. Whether its gametophytic stage represents what was described as G. occidentalis requires further investigation. Nevertheless, its sequence demonstrates that there are at least two species in the D. marginata complex in the West Indies.

Figures

Figure 1: Species groups in the Galaxauraceae determined with UPGMA clustering of the COI-5P genetic barcode, with Scinaia and Liagora as outgroups. Sequences generated for this study are in bold text.

Figure 2: Phylogeny of the Galaxauraceae based on maximum-likelihood analyses of rbcL sequences. Branch values are bootstrap supports for ML (1000 replicates) followed by Bayesian posterior probabilities expressed as a percentage of support out of 1. An asterisk (*) indicates 100% support for both robustness metrics while a dash (-) indicates support values <60%. Sequences generated for this study are in bold text.

Figures 3–6: Dichotomaria marginata. (3) Lectotype of Corallina marginata (=Dichotomaria marginata): Ellis and Solander illustration (1786, pl. 22 figure 6). (4) Sample from St. Croix (STX032), scale bar=2 cm. (5) Section through outer cortex showing subcortical cell bearing a pair of assimilatory outer cortical cells, scale bar=25 µm. (6) Surface view of outer cortical assimilatory cells (STX054), scale bar=25 µm.