Dichotomaria marginata (J. Ellis et Solander) Lamarck 1816 , p. 146

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

publication ID

https://doi.org/ 10.1515/bot-2015-0068

DOI

https://doi.org/10.5281/zenodo.11354172

persistent identifier

https://treatment.plazi.org/id/83772245-D45E-D242-FF53-F995F6799637

treatment provided by

Felipe

scientific name

Dichotomaria marginata (J. Ellis et Solander) Lamarck 1816 , p. 146
status

 

Dichotomaria marginata (J. Ellis et Solander) Lamarck 1816, p. 146 ( Figures 3–6 View Figures 3–6 )

Basionym

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

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 View Figures 3–6 ), TRP / CEL / EDS 13-25-9 [ STX 054] (see Table 1 View 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 View Figure 1 and 2 View Figure 2 ) as true representatives of D. marginata in the West 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 View Figures 3–6 ). 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 View Figures 3–6 ), and appear circular to ellipsoidal in surface view ( Figure 6 View Figures 3–6 ). 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 View Figures 3–6 ). The subcortical cells are transversely ovoid to rectangular, and occasionally subspherical at the margins ( Figure 5 View Figures 3–6 ).

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 View Figure 1 and 2 View Figure 2 , Tables 1 View Table 1 and 2 View Table 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.

Table 1: Collection details for isolates included in the molecular analyses of this study with newly generated GenBank accession numbers in bold type.

Species Voucher nos. Collectors/date Collection site COI-5 P rbc L
Galaxauraceae Actinotrichia fragilis (Forsskål) BØrgesen GWS 000151 J. Huisman/ 17 Aug. 1995 Ningaloo Reef, Western Australia, Australia KT886155  
  T. Schils, K. Pauly and E. Demeulenaere/ 28 Oct. 2004 Bandar Khayran, Capital Area, Oman   EU 095253
  CNU 32154 View Materials 20 Jan. 2006 Bonbon, Cagayan de Oro, Philippines KC609385  
Actinotrichia robusta Itono S- L. Liu and S. M. Lin/ 1 Apr. 2003 3rd Nuclear Power Outlet, Kenting National Park , Taiwan   AY688011
  CNU 32279 View Materials K. Lewmanomont / 6 Apr. 2010 Similan I., Phang Nga, Thailand KC609386  
Dichotomaria apiculata (Kjellman) Kurihara et Masuda SAP 095732 16 Jun. 2002 Reihoku , Amakusa , Kumamoto Prefecture, Japan   AB117635
  TUNG 05369 S.- M. Lin and S.- L. Liu/21 Jul. 2002 Sail Rock, Kenting National Park, Taiwan   AY688020
  CNU 32163 View Materials 3 Dec. 2002 Sungsan, Jeju, South Korea KC768178  
Dichotomaria australis (Sonder) Huisman, J. T. Harper et G. W. SAP 101111 A. Kurihara and S. Shimada / 28 Nov. 2003 No. 16 Beach, Rye, Victoria, Australia   AB258443
Saunders SAP 101108 About SAP A. Kurihara and S. Shimada / 4 Dec. 2003 Jervis Bay, New South Wales, Australia   AB258440
Dichotomaria diesingiana (Zanardini) Huisman, J. T. Harper et G. W. Saunders M. Hommersand / 9 Jul. 1993 Sharks Bay, Port Alfred, Cape Province, South Africa   AY688026
Dichotomaria falcata (Kjellman) 24 Jul. 2001 Toji, Shimoda, Shizuoka Prefecture, Japan   AB117629
Kurihara et Masuda CNU 032192 View Materials K. M. Kim/ 31 Jul. 2009 Oura Bay, Shimoda, Japan KF752527  
Dichotomaria hommersandii S.- L. Liu et S.- M. Lin M. Hommersand / 20 Jul. 1993 Riet River, Port Alfred, Cape Province, South Africa KC253901 JX072968
Dichotomaria huismanii C. W. Schneider, Popolizio et CWS / CEL / TRP 10-5 - 13 About CEL [ BDA 0024 ] C. W. Schneider , C. E. Lane, T. R. Popolizio / 19 Aug. 2010 Off Frick’s Beach , Tucker’s Town, Bermuda I., Bermuda (10–12 m) KU321660  
Spagnuolo TRP 12-117- 5 [ BDA 1492 ] (holotype) T. R. Popolizio / 20 Sep. 2012 Hog Breaker , north shore Bermuda I., Bermuda (12 m) KU321661 KU321674
  TRP 12-151 - 11 [ BDA 1669 ] T. R. Popolizio / 16 Nov. 2012 Southwest of North Rock , Bermuda I., Bermuda (12 m) KU321659  
Dichotomaria intermedia WRT 1934 -164 W. R. Taylor / 17 Jan. 1934 Isabela Island , Galapagos I., Ecuador   KF752506
( R. C. Y. Chou) Wiriyadamrikul , M. J. Wynne et S. M. Boo CNU 032199 View Materials K. M. Kim / 24 Oct. 2009 Gerupuk, Lombok, Indonesia KF752532 KF752509
Dichotomaria latifolia ined. ( Galaxaura latifolia Tak. Tanaka) S.- L. Liu and W. L. Wang / 25 Jan. 2003 Tahsianglan, Taipei County, Taiwan KF752529 AY688021
T

Tavera, Department of Geology and Geophysics

R

Departamento de Geologia, Universidad de Chile

C

University of Copenhagen

E

Royal Botanic Garden Edinburgh

CEL

University of Illinois

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

L

Nationaal Herbarium Nederland, Leiden University branch

J

University of the Witwatersrand

K

Royal Botanic Gardens

EU

Hubei University

S-

Department of Botany, Swedish Museum of Natural History

S

Department of Botany, Swedish Museum of Natural History

M

Botanische Staatssammlung München

I

"Alexandru Ioan Cuza" University

TUNG

Tunghai University

G

Conservatoire et Jardin botaniques de la Ville de Genève

W

Naturhistorisches Museum Wien

A

Harvard University - Arnold Arboretum

Y

Yale University

V

Royal British Columbia Museum - Herbarium

H

University of Helsinki

US

University of Stellenbosch

O

Botanical Museum - University of Oslo

KNP

South African National Parks

KU

Biodiversity Institute, University of Kansas

B

Botanischer Garten und Botanisches Museum Berlin-Dahlem, Zentraleinrichtung der Freien Universitaet

SAP

Hokkaido University

Kingdom

Plantae

Phylum

Rhodophyta

Class

Florideophyceae

Order

Nemaliales

Family

Galaxauraceae

Genus

Dichotomaria

Loc

Dichotomaria marginata (J. Ellis et Solander) Lamarck 1816 , p. 146

Schneider, Craig W., Popolizio, Thea R., Spagnuolo, Dylan S. & Lane, Christopher E. 2016
2016
Loc

Dichotomaria marginata (J. Ellis et Solander)

Lamarck, J. B. A. P. de 1816: 146
1816
Loc

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

Ellis, J. & D. Solander 1786: 115
1786
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