Ulva clathrata (Roth) Agardh, 1811

Santos, Alana Araujo Dos & Moura, Carlos Wallace Do Nascimento, 2011, Additions to the epiphytic macroalgae flora of Bahia and Brazil, Phytotaxa 28, pp. 53-64 : 59-61

Ulva clathrata ( Figs 3 A–E )

Conferva clathrata Roth (1806: 175–178) .

Thallus erect, cylindrical, flaccid to rigid, densely branched, olive-green, up to 4 cm long, fixed by extensions of rhizoid cells originating from the basal portion of the thallus, forming a small holdfast. Principal axis (100.0–)108.5(–115.0) µm width, with long branches from the basal region to the apex, (55–)71(–100) µm width; short, spiny multiseriate proliferations along the thallus. Cells square to polygonal, without any apparent organizing pattern, (20.0–)28.5(–40.0) µm long and (20–)33(–40) µm in diameter along the principal axis, and branches (15.0–)18.5(–27.5) µm in diameter. Chloroplast parietal, margin lobed, 6 to 9 pyrenoids.

Representative specimens examined:— BRAZIL. Bahia: Ilha de Itaparica, Vera Cruz , Praia da Penha , 25/ XI/2007, Santos & Alves ( HUEFS 130889 ) . Praia da Barra Grande , 19/III/2007, Santos ( HUEFS 147560 ) ; 18/ V/2007, Santos ( HUEFS 147561 ) ; 14/VII/2007, Santos ( HUEFS 147562 ) .

Geographic distribution along the west coast of Atlantic Ocean:— Canada to Georgia, Bermuda, Cuba, Puerto Rico, Venezuela, Brazil ( Taylor 1960, Kanagawa 1983, Santos 1983, Ganesan 1989, Schneider & Searles 1991, Littler & Littler 2000, Suárez 2005, Dawes & Mathieson 2008).

Comments:—The general aspects of the thalli (which are densely ramified, with multiseriate proliferations, spiny along their entire length) ( Figs 3A–C ) as well as the great numbers of pyrenoids are important characteristics for delimiting this species ( Fig. 3E ). Some authors have reported variations in the numbers of pyrenoids per cell within the different regions of the thallus of U. clathrata . Brodie et al. (2007) reported 5–15 pyrenoids in cells in the basal region of the thallus, and (1–)2–3 pyrenoids in cells in the apical region. Kraft (2007) reported 5–9 pyrenoids in cells in the basal region and 2–4 pyrenoids in cells in the apical region of the thallus. In the specimens analyzed here, the numbers of pyrenoids were not observed to vary between the basal and apical regions of the thallus, with 6–9 pyrenoids per cell being uniformly found. This data was similar to that published by Burrows (1991; 5–10 pyrenoids per cell) for the British Islands and Kanagawa (1983; 2–8 pyrenoids per cell) for São Paulo.

The general aspect of the thallus of specimens of U. clathrata from Australia, as described and illustrated by Kraft (2007), with branches with bulbous apices, differed from the other references consulted that described the species as having densely ramified thalli with spiny proliferations ( Kanagawa 1983, Burrows 1991, Brodie et al. 2007).

This is the first citation of U. clathrata for the coast of Bahia State, although the species is widely distributed along the Brazilian coast with records from the states of Maranhão ( Ferreira-Correia & Brandão 1974), Ceará ( Pinheiro-Joventino et al. 1998), Alagoas ( Muniz 1983), Espírito Santo ( Barata 2004), Rio de Janeiro (Reis & Yoneshigue-Valentin 1996), São Paulo ( Kanagawa 1983), Paraná ( Shirata et al. 1991), Santa Catarina ( Santos 1983), and Rio Grande do Sul ( Horta 2000).

Ulva flexuosa subsp. paradoxa ( Figs 3 F–K )

Conferva paradoxa Dillwyn (1809 : xxii).

Thallus erect, cylindrical, flaccid, delicate, light green, (0.6–)3.0(–10.0) mm long, fixed by prolongations of rhizoidal cells at the base, forming a small holdfast. Principal axis (60–)115(–150) µm width, with dense ramifications, opposite to irregular, with pluriseriate branches and short uniseriate branchlets (up to 900 µm long) along the thallus. Cells square or rectangular, organized longitudinally, (15.0–)26.5(–37.5) µm long and (10–)24(–45) µm width; branches uniseriate with isodiametric cells (5.0–)9.5(–15) µm width. Chloroplast parietal, laminar, lobed, with (4–)6–7 pyrenoids.

Representative specimens examined:— BRAZIL. Bahia: Vera Cruz, Ilha de Itaparica, Praia da Penha, 18/ III/2007, Moura ( HUEFS 130885 ) ; 19/V/2007, Santos ( HUEFS 130886 ) ; 14/VII/2007, Alves & Peixoto ( HUEFS 130887 ) ; 27/IX/2007, Santos & Peixoto ( HUEFS 130888 ) ; 23/I/2008, Santos ( HUEFS 147558 ) ; 08/ III/2008, Santos ( HUEFS 147559 ) ; Praia da Barra Grande , 19/III/2007, Santos ( HUEFS 147560 ) ; 18/V/2007, Santos ( HUEFS 147561 ) ; 14/VII/2007, Santos ( HUEFS 147562 ) ; 27/IX/2007, Oliveira & Oliveira ( HUEFS 130890 ) .

Geographic distribution along the west coast of Atlantic Ocean:— Canada to South Carolina, Florida, Gulf of Mexico, Cuba, Venezuela, Brazil, Uruguay ( Taylor 1960, Kanagawa 1984, Ganesan 1989, Schneider & Searles 1991, Littler & Littler 2000, Suárez 2005, Dawes & Mathieson 2008).

Comments:— Ulva flexuosa subsp. paradoxa was cited for Paraíba State along the Brazilian coast by Kanagawa (1984, as Enteromorpha paradoxa (Dilwin) Kützing (1845: 247) , for Espírito Santo State by Barata (2004, as E. paradoxa ), for São Paulo State by Coto (2007, as Ulva paradoxa Agardh (1817 : xxii)), and for Rio de Janeiro by Reis & Yoneshigue-Valentin (1996, as E. paradoxa ). This is the first reference of this taxon for the coast of Bahia State.

Of all of the descriptions and illustrations presented by Brazilian authors, apparently only Kanagawa (1984) was referring to Ulva flexuosa subsp. paradoxa . The specimens described by Barata (2004) and Coto (2007) are morphologically similar to the specimens of U. flexuosa subsp. flexuosa , although the numbers of pyrenoids are similar to those reported by Kanagawa (1984) and in the present study ( Fig. 3K ). Additionally, these authors did not mention the characteristic uniseriate branches of this taxon ( Figs 3G–H ); both described the presence of spiny branches along the thallus, although these are not evident in their illustrations. In light of these discrepancies, it will be necessary to review the citations of this taxon for the Brazilian coast.

Bliding (1963), Wynne (2011) and Kraft (2007) referred to this taxon as a subspecies of Ulva flexuosa , a designation that was adopted in the present study; all of the citations of this subspecies for Brazil are referred to as Enteromorpha paradoxa or U. paradoxa as these authors considered the morphological differences between U. flexuosa subsp. flexuosa (as U. flexuosa ) and U. flexuosa subsp. paradoxa (as E. paradoxa or U. paradoxa ) consistent, delimiting it as a distinct species ( Kanagawa 1984, Barata 2004, Coto 2007).

Figures

FIGURES 3 A–E: Ulva clathrata. A: General aspect of the thallus. B: Detail of the multiseriate branches along the plant axis. C: Detail of a branch with short, spiny branchlets. D: Cells without any pattern of organization. E: Cells with parietal chloroplasts, with lobed margin and pyrenoids. FIGURES 3 F–K: Ulva flexuosa subsp. paradoxa: F: General aspect of the thallus. G–H: Branch with uniseriate branchlets. I. Base of the thallus with rhizoidal cells. J. Cells with longitudinal organizational patterns. K. Parietal chloroplast with pyrenoids.