Cladophora coelothrix Kutzing 1843

3. Cladophora coelothrix Kützing (1843a: 272.). Map 1; Figs. 1F–G Thalli dark green to olive-colored, forming tufts or dense stiff cushions. Specimens (1 –) 3 (– 4) cm high (in some cases, reaching 9 cm in height). Species attachment by unicellular rhizoids sprouting from basal cells, formed at the basal poles of the main axis cells. Ramification pseudo-dichotomous or unilateral. Apical cells with rounded tips, measuring (81 –) 98 (– 118) µm wide and (520 –) 786 (– 1054) µm long with L/W ratio of (6 –) 8 (– 11). Cells of ultimate branches (83 –) 99 (– 116) µm wide and (496 –) 627 (– 792) µm long with L/W ratio (5 –) 7 (– 9). Cells of the main axes (92 –) 109 (– 123) µm wide and (618 –) 818 (– 1067) µm long with L/W ratio (6 –) 8 (– 11). Representative specimens examined: BRAZIL: Piauí: Luís Corrêa, Praia do Coqueiro, 14/V/1999, Batista (PEUFR 42547); Paraíba: João Pessoa, Ponta do Cabo Branco, 07 Oct. 2002, Gestinari & Kanagawa (PEUFR 42548); Jacumã, Praia do Conde, 31 Jan. 1982, Kanagawa (JPB 10677; SPF 25045); Pernambuco: Goiana, Praia de Carne de Vaca, 20 Jul. 2001, Gestinari & Torres (PEUFR 42549); Recife, Praia de Boa Viagem, 30 Sept. 2000, Gestinari & Torres (PEUFR 42564); 11 Mar.2001, Gestinari & Torres (PEUFR 42565); Ipojuca, Praia de Cupe, 21 Jun.2001, Gestinari & Torres (PEUFR 42553); Praia de Porto de Galinhas, 29 Sept. 2000, Gestinari & Torres (PEUFR 42557); Praia de Serrambi, 13 Nov.2000, Gestinari & Torres (PEUFR 42560); Alagoas: Maceió, Praia das Sereias, 04 Oct. 2002, Gestinari & Guedes (PEUFR 42569); Bahia: Uruçuca, Praia de Serra Grande, 08 Oct. 1995, Nunes et al. (ALCB 49394, 34788); Mata de São João, Praia do Forte, 05 May 2000, Nunes et al. (ALCB 49402); Ilha de Itaparica, Barra do Gil, 28 Nov. 1981, Ugadim (SPF 29737)); Espírito Santo: Aracruz, Praia de Portocel, 30 Jun. 2003, Nassar (PEUFR 42570); Rio de Janeiro: Búzios, Praia Rasa, 09 Jan. 2001, Gestinari & Torres (PEUFR 42571); Santa Catarina: Laguna, Ponta do Iró, 05 Nov. 1952, Joly (SP 115280). Additional representative specimens examined: TRINIDAD: Chakachacane: Perruquier Bay, 09 Mar. 1958, Richardson (L 0441639). PUERTO RICO: Guajataca: North Coast, 01 Jan. 1962, Bernatowicz (L 0441732). Comments: The specimens formed tufts or dense cushions on rocky shores (PI, ES, RJ, SC) and formed dense cushions on reef plateaus (PB, PE, AL). Some specimens grew epiphytic on Phyllodictyon anastomosans, Valonia macrophysa Kützing (1843a: 307), Jania adhaerens, Bryocladia thyrsigera (J.Agardh) F.Schmitz in Falkenberg (1901: 169) and Laurencia sp. Among the accompanying species, we most commonly found Ulva spp., Cladophora dalmatica, C. montagneana, C. prolifera, Cladophoropsis membranacea (Hofman Bang ex C.Agardh) Børgesen (1905: 289), Valonia macrophysa, Dictyota pulchella, Padina gymnospora, Hypnea musciformis, Acanthophora spicifera (M.Vahl) Børgesen (1910: 201) and Palisada perforata. In addition, we observed that C. coelothrix was a host to Ulva sp., Erythrotrichia carnea (Dillwyn) Agardh (1883: 15), Pneophyllum fragile, Gayliella flaccida (Harvey ex Kützing) T.O.Cho & L.J.McIvor in Cho et al. (2008: 723), C. vagans, diatoms and cyanobacteria. Molecular phylogentic studies reveal that C. coelothrix is placed in the Siphonocladales-clade, along with a number of other Cladophora species, including C. aokii Yamada (1925: 85), C. prolifera, C. socialis Kützing (1849: 416), C. liebetruthii Grunow in Piccone (1884: 53), C. catenata and C. sibogae Reinbold (1905: 146) (Bakker et al. 1994, Leliaert et al. 2003 & 2007, Brodie et al. 2007), and according to recent phylogenetic studies based on LSU rDNA C. coelothrix is not a monophyletic taxon (Leliaert et al. 2007). Cladophora coelothrix is distributed from Piauí to the coast of Santa Catarina, being a very common species in intertidal zones. We found little variation in cell width and in L/W ratio. Samples from Espírito Santo had the highest values. The specimens that we analyzed fit descriptions of species in the Mediterranean (Hoek 1963), the North Atlantic (Hoek 1982), the west coast of tropical Africa (Lawson & John 1982), South Australia (Hoek & Womersley 1984) and the coast of Japan (Hoek & Chihara 2000). According to Hoek & Chihara (2000), C. coelothrix has a worldwide distribution in tropical seas and it penetrates into subtropical and warm-temperate margins of the southern and northern hemispheres. In Europe, a cold water-adapted ecotype reaches the shores of the British Channel.Published as part of Gestinari, Lísia Mônica De Souza, Pereira, Sonia Maria Barreto & Yoneshigue-Valentin, Yocie, 2010, Distribution of Cladophora Species (Cladophorales, Chlorophyta) along the Brazilian Coast, pp. 22-42 in Phytotaxa 14 on pages 27-28, DOI: 10.11646/phytotaxa.14.1.2, http://zenodo.org/record/477872