Sphacelaria rigidula

Sphacelaria rigidula Kützing

Sphacelaria rigidula Kützing, 1843:292; Kützing, 1855:25, pl. 86: fig. 1; De Toni, 1895a:50; Prud’homme van Reine, 1982:203, figs. 508–554; R. Aguilar-Rosas and Machado Galindo, 1990:188; Yoshida et al., 1990:281; Stewart, 1991:51; González-González, 1993:443; León-Tejera and González-González, 1993:498; León-Tejera et al., 1993:200; Mateo-Cid et al., 1993:50; Prud’homme van Reine, 1993:149; Servière-Zaragoza

et al., 1993:482; Kitayama, 1994:72, figs. 22–28; González-González et al., 1996:300; Yoshida, 1998:200, fig. 2-3 D; L. Aguilar-Rosas et al., 2000:132; Mendoza-González et al., 2000:27, figs. 34–37; L. Aguilar-Rosas et al., 2002:235; Lipkin and Silva, 2002:41; Abbott and Huisman, 2004:190, fig. 72C; López et al., 2004:10; R. Aguilar-Rosas et al., 2005b:35; Keum et al., 2005:4, figs. 1–12; Riosmena-Rodríguez et al., 2005:101; Mateo-Cid et al., 2006:49, 57; Servière-Zaragoza et al., 2007:8; Pedroche et al., 2008:33.

Sphacelaria furcigera Kützing, 1855:27, pl. 90: fig. 2; Setchell and Gardner, 1924a:724, pl. 19: fig. 58; Setchell and Gardner, 1925:396, pl. 37: fig. 29; Setchell and Gardner, 1930:138; Dawson, 1944:224; Dawson, 1951:52; Dawson, 1954d:400, fig. 14h; Dawson, 1957b:9; Dawson, 1959a:18; Dawson, 1959c:4; Dawson et al., 1960a:10; Dawson, 1966a:10; Dawson and Neushul, 1966:174; van den Hoek and Flinterman, 1968:193; Abbott and Hollenberg, 1976:218, fig. 181; Pacheco-Ruíz, 1982:70; Stewart, 1982:54; Schnetter and Bula Meyer, 1982:59, pl. 8: fig. I; Stewart and Stewart, 1984:141; Huerta-Múzquiz and Mendoza-González, 1985:44; Sánchez-Rodríguez et al., 1989:41; González-González et al., 1996:299; Hoffmann and Santelices, 1997:138, fig. 34.

Algae small filamentous tufts, up to 1 cm tall; axes and branches uniseriate near tips, each with a conspicuous apical cell; cells below multiseriate with 1–7 longitudinal walls per segment in side view; attached by rhizoidal filaments or discoid base. Axes sparsely, irregularly branched; axes and branches of similar diameter, (16–)25–45 µm in diameter; segments as long as or longer than wide. Secondary transverse cell walls occasional within longitudinal sections of segments. Phaeophycean hairs present.

Propagules Y-shaped; stalk basally narrowed, terminally with a slightly protruding central apical cell, and 2(–3) lateral, long, slender, cylindrical arms of more or less the same length (170–400 µm) and diameter (20–25 µm); each arm with a conspicuous apical cell. Unilocular sporangia on 1-cell pedicel, mostly spherical, 55–80 µm in diameter. Plurilocular sporangia on 1-cell pedicel, elongate-ovoid, 55–63 µm long and 40–50 µm in diameter; two kinds, one with numerous small locules, another with fewer and larger locules (“male and female gametangia” of Setchell and Gardner, 1924a:pl. 19, fig. 58).

HABITAT. Partially endophytic within host cells and epiphytic above host surface; on various algae, notably on Sargassum and Padina, and epizoic on a parrotfish “beak” (Dawson, 1959a); mid intertidal to shallow subtidal.

DISTRIBUTION. Gulf of California: El Coloradito to Ensenada de San Francisco (vicinity of Guaymas); La Paz to Punta Palmilla (vicinity of San José del Cabo). Pacific coast: Alaska to southern California; Isla Guadalupe; Punta de la Asunción, Baja California Sur to Oaxaca; Isla San Benedicto (Islas Revillagigedo); Clipperton Island; Costa Rica; Colombia; Chile; Hawaiian Islands; Korea; Japan.

TYPE LOCALITY. On Cystoseira triquetra, Nuweiba, Sinai, on the Gulf of Aqaba, Red Sea, Egypt.